Quantitative Determination of Amorphous and Crystalline Drug in Polymer Microspheres. Leonard C. Thomas (TA Instruments, USA)

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1 Spring 2003 TECH Talk New Products New Product Brochures Training Courses New Staff at TA Instruments Conferences & Exhibitions The Lighter Side FREE Posters Rheology Software Update Finance with GE Vendor Financial Services CURRENT PROMOTIONS Quantitative Determination of Amorphous and Crystalline Drug in Polymer Microspheres Leonard C. Thomas (TA Instruments, USA) An important technology for controlling the release rate of a drug or protein within the body is through the use of biodegradable polymer microspheres. The release rate is controlled by several factors, three of which are the drug form (amorphous or crystalline), its concentration within the microsphere, and its crystalline structure. DSC, MDSC, and TGA are powerful tools in measuring these factors in a drug delivery system. Full Article Measuring the Glass Transition of Amorphous Engineering Thermoplastics Dr. Bruce Cassel (TA Instruments, USA) Advanced Tzero technology provides superior capabilities for the analysis of amorphous thermoplastic alloys, and their constituent homopolymers. These include improvements in specific heat data from a single run, and MDSC capability in glass transition detection and determination. Full Article Featured Technical Articles The Use of Tzero and Modulated DSC for the Characterization of Milk Powders Jacques Loubens, TA France Milk powders are biological samples that are complex mixtures of sugars, fats, and proteins. A knowledge of their thermal properties aids in product process control, the prediction of storage characteristics, and in nutrition. The advent of Tzero DSC technology permits improved analysis of milk powders due to its advantages over standard DSC in baseline flatness, sensitivity, and resolution. Full Article New Approach to Characterize Starch Dispersions A.J. Franck, TA Instruments The new Starch Pasting Rheometer and Smart Swap Starch Pasting Cell are designed for enhanced starch characterization, and minimizing water losses during the cooking cycle. Mounted on a sensitive rheometer, the starch cell provides an accurate and powerful tool to characterize the gelatinization of starch products as well as the properties of starch gels. Full Article Contact Us

2 Quantitative Determination of Amorphous and Crystalline Drug in Polymer Microspheres Leonard C. Thomas TA Instruments, 109 Lukens Drive, New Castle DE 19720, USA BACKGROUND One of the latest technologies for controlling the release rate of a drug or protein within the body is through the use of biodegradable polymer microspheres that have an average size of µm. This small size permits the microspheres to be inhaled as part of a spray or to be injected as they are held in suspension in a solution. The actual release rate is controlled by a variety of factors, including: Size and permeability of the particle Distribution of the drug within the particle Form of the drug: amorphous or crystalline Type of crystalline structure (polymorphs) Concentration of drug within the polymer microsphere The combination of differential scanning calorimetry (DSC), modulated DSC (MDSC ) and thermogravimetry (TGA) is used to measure the latter three factors on a drug delivery system using polymer microspheres. DETAILS It has been shown that multiple heating rates should be used to determine the tendency of the crystalline drug to undergo polymorphic transformations as the sample is heated (1). Figure 1 shows a plot of heat capacity versus temperature for three samples of drug microspheres heated at 1, 10 and 50 C/min. At the lower heating rates, multiple melting peaks are observed in the range from 70 to 180 C while the 50 C/min rate produces predominantly a single peak. The step change observed in all runs between 30 and 60 C is due to the glass transitions of the polymer and amorphous drug, which are completely miscible. Quantitative results for determining the amount of crystalline drug are shown in Figure 2 run at 50 C/min to eliminate or minimize polymorphic transformation. Since the pure drug has a heat fusion of 98 J/g (Figure 3), the total area of 12.6 J/g indicates that there is about 13 % crystalline drug in the sample. Note that the second heat of the same sample does not show any melting peak indicating that the drug is now only present in the amorphous form. Since the sample changes from a crystalline to an amorphous structure once it is heated, there should be a corresponding increase in the size of the glass transition on the second heat. This can be seen in Figure 4, a comparison of glass transitions from the first 1 TA303

3 and second heats obtained by modulated DSC. Using a value of 0.53 J/g C for the change in Cp due to a 100 % amorphous drug (Figure 3), an increase of 13 % ([ ] 100 %/ 0.53) in the amorphous content is seen in the second versus first heats. This agrees very well with the previous measurement of 13%, which used crystalline peak areas. Since the amorphous drug is completely miscible with the polymer microspheres, it is not possible to measure the total amount of drug in the microspheres from the size of the glass transition. Therefore, it is necessary to see if the decomposition of the drug microspheres is sufficiently different from the placebo microspheres in order to determine the drug concentration. Figure 5 shows TGA data on the placebo microspheres run at 10 C/min. The value of 98.7 weight percent at 150 C and the rate of weight loss of 0.04 %/min at 400 C are compared with the drug microsphere data seen in Figure 6. Since the drug is a monohydrate with 5 % water, the amount of crystalline monohydrate can be calculated from the difference in weights at 150 C. Just as with the DSC and MDSC measurements, a concentration of 13 % crystalline drug is found x 100 = 13 % Essentially the entire rate of weight loss at 400 C is due to the drug and not the polymer microspheres. Therefore, the percent drug can be calculated by the ratio of the rate of weight losses for a 100 % drug sample (2.24 %/min; not shown) and the drug microspheres with only a small correction (0.04) due to the polymer. SUMMARY % Drug = = 30% 2.24 DSC, MDSC and TGA data all show that the drug microspheres contain approximately 13 % crystalline drug monohydrate. TGA data shows the total drug concentration to be 30 %, which means that the drug microspheres contain 17 % amorphous drug. REFERENCES 1. L. C. Thomas, Characterization of Polymorphic Transitions in a Pharmaceutical Drug by DSC and MDSC, Proceedings of the 30 th Conference of the North American Thermal Analysis Society, 2002, pp KEYWORDS differential scanning calorimetry, glass transition, modulated differential scanning calorimetry, pharmaceuticals, thermogravimetry 2 TA303

4 Figure 1 Effect of Heating Rate on Polymorphic Conversion in Drug Containing Microspheres Figure 2 First and Second Heat of Pure Drug 3 TA303

5 Figure 3 Enthalpy of Pure Drug Figure 4 Glass Transition of Amorphous Drug 4 TA303

6 Figure 5 TGA Weight Loss of Placebo Microspheres Figure 6 TGA Weight Loss Curve of Drug Containing Microspheres 5 TA303

7 TA Instruments United States, 109 Lukens Drive, New Castle, DE Phone: Fax: United Kingdom Phone: Fax: Spain Phone: Fax: Belgium/Luxembourg Phone: Fax: Netherlands Phone: Fax: Germany Phone: Fax: France Phone: Fax: Italy Phone: Fax: Sweden/Norway Phone: Fax: Japan Phone: ) Fax: Australia Phone: Fax: steve_shamis@waters.com To contact your local TA Instruments representative visit our website at 6 TA303

8 The Use of Tzero and Modulated DSC for the Characterization of Milk Powders Jacques Loubens TA Instruments France, S.A, 1 rue Jacques Monod, Guyancourt, France ABSTRACT Milk powders are examples of biological samples that are often complex mixtures of sugars, fats and proteins. Thermal properties aid in product process control, the prediction of storage characteristics and in alimentation. Traditional limitations of DSC are overcome by the new Tzero technology along with its improvements in sensitivity, quality of baseline, resolution, and wider modulation conditions in MDSC experiments. Two examples from milk powders are studied here. INTRODUCTION Differential Scanning Calorimetry (DSC) is used widely to characterize biological materials. Typical observed transitions include the glass transition of the amorphous phase, melting and crystallization processes, denaturation, free and bound water, onset of oxidation, and heat capacity. Tzero DSC technology, with its attendant sensitivity and resolution, is ideal for examining these low energy processes. Modulated DSC is another useful tool that aids in the determination and interpretation of the complex DSC profiles typical of biological samples. EXPERIMENTAL Two dry milk powders were characterized using Tzero DSC and Modulated DSC, to identify and quantify the components, and the type (amorphous or crystalline) of structure present. The first sample, a whey (lactoserum) powder, is a biological liquid derived from milk by ultra-filtration and extraction of lipids. It is then concentrated by vacuum evaporation, and crystallization of lactose (alpha monohydrate form, MW = 360 g/mol). The sample is then dried by atomization. The result is a lactose crystallized dry powder containing a minor amorphous phase (2). Fats from original milk are no longer present, and the resultant powder is a non-fat milk powder. The glass transition temperature of the amorphous phase depends on the drying conditions. To examine the material for the glass transition, heat-only modulated conditions (10 C/min, amplitude ± 0.8 C, period 30 s) are chosen, keeping the heating rate equivalent to standard DSC. Aluminum hermetic pans are used. 1 TA304

9 Figure 1 Non-Fat Milk Powder The second sample is a fat containing milk powder. The fabrication process is the same as that for the non-fat milk powder except that before drying, a determined quantity of fat (here coconut oil) is added. The major components of this powder are alpha lactose and lipids. Thermal characterization includes the determination of the glass transition of the amorphous phase of lactose, and the quantitation of the melting endotherm of the lipids. The sample is examined at 10 C/min. The second sample is also run in Advanced Modulated DSC, at 10 C/min, in heat-only conditions (amplitude ± 0.8 C, period 30 s). RESULTS AND DISCUSSION Figure 1 shows the MDSC thermal curve for the non-fat milk powder. The upper curve represents the total heat flow, the middle curve the reversing heat flow and the lower curve, the nonreversing heat flow. The figure shows that the total heat flow curve is difficult to interpret because of the overlapping glass transition and enthalpic relaxation. The measurement by Modulated DSC of the non-fat milk powder (first sample) separates the glass transition (resolved in the reversing heat flow) from the enthalpic relaxation (in the nonreversing heat flow). The use of high heating rate and short period produces several cycles in the glass transition, a necessary condition for deconvolution of MDSC signals. This set of conditions is only available with Advanced Tzero technology. The change in specific heat capacity (0.29 J g -1 C -1 ) at the glass transition is directly measured upon first heating by Modulated DSC. The amount of amorphous phase may then be quantified, becoming a quick control quality check of the milk powder. 2 TA304

10 The measurement by DSC of the fat containing milk powder (second sample) is shown in Figure 2. The figure shows only a two-step endotherm, which is the melt of the fats in the same temperature region. But the glass transition of the amorphous phase of lactose is hidden (figure 2). The fat level is quantified by integration of the melt endotherm from the DSC baseline (about 12.4 J g -1 ). Figure 2 Fat Containing Milk Powder The measurement of the fat containing milk powder by modulated DSC gives a more complete understanding of the second sample, with the interpretation of reversing and nonreversing heat flows as shown in Figure 3. There is a clear separation of the glass transition of the amorphous phase of lactose (resolved in the reversing signal) from the melting of the fats (completely resolved in the nonreversing signal). The heat capacity change (0.17 J g -1 C -1 ) is then directly determined at first run, and also the correct quantification of the enthalpy of melting of fats in the nonreversing heat flow (10 J g -1 ). CONCLUSION The glass transition of milk powders is used to quantify the lactose content even in the presence of overlapping melting of fat. These biological examples confirm the accuracy and usefulness of the Tzero DSC and Modulated Tzero DSC. Sensitivity, baseline quality, wide range of modulation conditions are determinant for accurate characterization of samples of biological materials. 3 TA304

11 Figure 3 MDSC of Fat Containing Milk Powder REFERENCES 1. R. Danley, T. Kelly, and J. Groh, Improved DSC Performance Using Tzero Technology, International Laboratory, 2001, XXVI (April), pp P. Schuck, M. Piot, S. Méjean, J. Fauquant, G. Brulé and J.L. Maubois, Dehydratation of Milks Enriched with Micellar Casein by Microfiltration- Comparison of the Obtained Powder Properties, Lait, 1994, 74, pp KEYWORDS differential scanning calorimetry, biologicals, foods, glass transition, modulated differential scanning calorimetry 4 TA304

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13 Measuring the Glass Transition of Amorphous Engineering Thermoplastics R. Bruce Cassel, Ph.D. TA Instruments, Inc., 109 Lukens Drive, New Castle DE 19720, USA ABSTRACT DSC is a useful tool for characterizing the glass transition region of amorphous thermoplastics. The Q1000 DSC, with its Advanced Tzero Technology, provides improved specific heat data obtained directly from a single run. It also provides improvements in Modulated DSC capability for glass transition analysis of amorphous thermoplastic alloys and their constituent homopolymers. BACKGROUND Amorphous thermoplastics have especially desirable properties of optical clarity and impact resistance. For example, polycarbonate (PC) is used for eyeglasses and compact disk storage media, and acrylonitrile-butadiene-styrene terpolymer (ABS) is used for sports equipment and telephone housings. Unlike semi-crystalline ºC/min Heat Flow T4P (W/g) C(H) Exo Up Temperature ( C) Figure 1 Glass Transition of Polycarbonate TA 309

14 thermoplastics that derive their physical properties from a mix of amorphous and crystalline structures, amorphous thermoplastics derive their mechanical properties solely from the characteristics of their amorphous phases. The amorphous phase is obtained by cooling a liquid under conditions that do not permit crystallization. Such cooling produces a solid without the long-range molecular order of a crystal. When heated, an amorphous solid undergoes softening over the glass transition region. Over this temperature range (of several tens of Celsius degrees) typically, the strength, hardness, storage modulus, etc. change by several orders of magnitude. The glass transition also results in an increase in volume, heat capacity, coefficient of expansion and molecular mobility. The glass transition temperature range is often adjusted during formulation to improve the physical properties, e.g., strength, flexibility or impact resistance, at the service temperature of the finished product. Differential scanning calorimtery (DSC) has long been used to quantify the glass transition temperature range by analyzing the heat flow to the sample specimen resulting from the change in heat capacity as shown for PC in Figure 1. Typically, a single temperature, called the glass transition temperature (Tg), is taken to represent the temperature range over which the glass transition takes place. Various industries have different preferences for this point (midpoint, inflection point, onset, etc.) so that high quality data analysis software provides several options for performing this determination. Additionally, the glass transition has a kinetic component so the value of Tg depends on how the measurement is made and on which physical property is being measured (1). For DSC, the experimental variables include the heating (or cooling) rate, the previous thermal treatment of the sample, and the use of temperature modulation to separate thermodynamic and kinetic components ºC/min ºC/min Heat Flow T4P (W/g) ºC/min Exo Up Temperature ( C) Figure 2 The Glass Transition of Polycarbonate at Three Heating Rates. The 10 ºC/min Data is from Three Samples Cooled at 5, 10 and 20 ºC/min. TA 309

15 EXPERIMENTAL A TA Instruments Q1000 DSC, equipped with a Refrigerated Cooling System (RCS), is used to collect this data. The Q1000 uses a novel sensor and signal treatment that removes the distortion caused by the DSC cell itself on the heat flow to the sample specimen (2, 3). The result is straighter baselines, sharper transitions, less thermal lag error, and less dependence of the DSC results on the details of the experimental conditions, such as the heating rate, sample size, and encapsulation (4). The polycarbonate test specimen is cut from a commercial CD-ROM used for computer for data storage. The acrylonitrile-butadiene-styrene terpolymer and ABS-PC blends are obtained from a resin suppler in the form of mechanical analysis test bars. Sample size is 10 to 20 mg. Initial runs are performed on samples as received and rerun data is analyzed after ballistic cooling from the previous run. RESULTS AND DISCUSSION Figure 2 shows DSC results for polycarbonate obtained at three different, commonly used heating rates after creating a common thermal history by cooling at 10 ºC/min. The displacement from the zero heat flow line is proportional to the heating rate, as is the change in this signal upon traversing the glass transition interval. Thus, for weak or broad glass transitions a fast heating rate is preferred. For this sample the data could be taken equally well at slower rates thus avoiding possible temperature gradients in the sample. The middle curve also show the overlay of three test specimens cooled at 5, 10 and 20 C/min Heat Capacity (J/g/ C) Temperature ( C) Figure 3 Polycarbonate Heat Capacity at 5, 10 and 20 C/min One of the benefits of presenting experimental data in the form of specific heat capacity is that data taken at different heating rates can easily be compared as shown in Figure 3. Advanced Tzero Technology provides the ability to determine specific heat capacity directly so that there is no need to make multiple runs to obtain this data. Changing between the presentation in Figure 2 and Figure 3 is only a change of displayed units, not in data treatment. This is because the Q1000 DSC removes the slope, offset and curvature component that normally distorts the DSC data. The single curve Cp data in Figure 3 is obtained without subtracting a baseline and obtains the same Cp data before and after the transition shows that these deleterious baseline effects have all been TA 309

16 removed through the use of the Tzero signals. The fact that the Cp data varies with heating rate within the glass transition region is a predictable variation due to the kinetic aspect of the glass transition. In formulating an amorphous thermoplastic to obtained desired improvements in physical properties, it is possible to shift the glass transition region, or to add an additional amorphous phase. Shifting the glass transition is achieved by incorporating another miscible polymer (or monomer) into the amorphous phase through copolymerization or blending. When two polymers are partially miscible, the Tg of the mixed amorphous phase will shift between the Tg s of the two homopolymers more or less proportionally to the amount of each component in the mixture. When two polymers are not completely miscible there will be two glass transitions, one for each amorphous phase. By controlling the amount of the two components in the copolymer or polymer blend, the glass transition(s) can be shifted to adjust the physical properties of the formulation Initial Run 2.0 Rev Cp (J/g/ C) Tg Rerun Reversing Cp Tg Heat Capacity (J/g/ C) Baseline Temperature ( C) Figure 4 Heat Capacity of ABS, Initial Heat, Reheat and Reheat Reversing Signal Acrylonitrile-butadiene-styrene terpolymer is a high performance thermoplastic containing two amorphous phases; a rubbery phase provided by butadiene, and a strength-lending styrene-acrylonitrile (SAN) copolymer two-component phase. It has two glass transitions. The low temperature glass transition is due to the butadiene phase, and the high temperature one is due to the SAN phase. The ratio of A to B to S determines the properties of ABS from essentially a hard rubber to a shock-resistant highmodulus material. Bair and coworkers showed that careful glass transition measurements are useful for determining the amount of these components in the terpolymer and therefore provide a tool for assessing the quality of ABS formulations (5). Bair s work found limited utility, however, due to the need to straighten the instrumental baseline of the then available instruments and to manually generate the heat capacity data. Advanced Tzero TM Technology and/or MDSC meets these needs and renders Bair s approach practical. Figure 4 shows the use of the Q1000 DSC with an RCS cooling accessory to determine the transitions in ABS. Because the low temperature transition is around 80 ºC, it is (just barely) within the range of the mechanical refrigerator of the RCS, therefore it was TA 309

17 not necessary to use a liquid nitrogen-cooling accessory to make these measurements. Also shown on this plot at the bottom of the figure is the DSC baseline. One necessity for accurate Tg measurements is a flat baseline since any underlying instrumental curvature will introduce error in the Tg. The slope in the Cp data is due to the actual increase in the test specimens heat capacity with temperature and is not an instrumentinduced artifact. The dashed line in Figure 4 is the rapidly reversing Cp data taken from an MDSC experiment. The use of MDSC is recommended for interpreting complex DSC curves since it provides confirmation of the interpretation and isolates the Tg. That is, in Figure 4 the rapidly reversing curve shows an unambiguous sigmoidal change in Cp at the glass transition thus enabling the accurate determination of Tg. The third amorphous engineering thermoplastic analyzed is a PC-ABS alloy containing a blend of polycarbonate and ABS copolymer and other additives to improve the interface between the two. When run by traditional DSC, the thermal curve shows a superimposition of endotherms and glass transitions such that it is difficult to accurately determine Tg. To improve the accuracy of the Tg measurements the analysis was carried out by MDSC. In this way the kinetic components appear on the nonreversing signal while the heat capacity components, which are to be analyzed, appear on the reversing signal. The conventional heat capacity obtained at constant heating rate (without the MDSC modulation) is the sum of these two curves C(H) J/g/ C Nonrev Cp (J/g/ C) Reversing Additive C(H) J/g/ C Rev Cp (J/g/ C) 0.2 Volatiles Tg Tg 1.2 Non-Reversing Temperature ( C) 1.0 Figure 5 - MDSC of PC-ABS Alloy Based on the ratio of the specific heats capacities at 0 ºC this material is a 50/50 % mixture. If there were no miscibility between the phases then the blend would TA 309

18 look like a simple addition of the two DSC curves. If there were complete miscibility there would be one Tg roughly midway between the SAN and PC glass transitions. If there were partial miscibility then the glass transitions of the mixed amorphous phases would be between the two Tg s of the components, exactly what is observed ABS C(H) J/g/ C ABS-PC C(H) J/g/ C C(H) J/g/ C C(H) J/g/ C Rev Cp (J/g/ C) PC Temperature ( C) Figure 6 Reversing Heat Capacity for PC, ABS and PC-ABS Alloy 1.2 Assuming that the shift in Tg s is proportional to the amount of each component then the amorphous phase with the lower Tg is 8 % PC and 92 % SAN, and the amorphous phase with the higher Tg is 13 % SAN and 87 % PC. By improving the miscibility of the amorphous phases the formulation increases the bonding across the phase boundaries and improves the physical properties of the blend. The thermal curves showing the Tg determinations are shown in Figure 6. Further insight may be able to be obtained from use of the change in heat capacity, that occurs over each of the glass transition interval, be proportional to the amount of material in each of these phases. While this approach would be valid for the case where the ABS and PC components are from the same stock in the blend and homopolymers, in this case the analysis is only illustrative because the components are not known in detail. SUMMARY DSC is a useful tool for characterizing amorphous thermoplastics by determining the glass transition temperatures. This technique is especially useful in the characterization of copolymers and blends where this information may be directly applied to determining the formulation changes required to improve physical properties., The Q Series DSCs offer improved technology, namely, straighter baselines, improved sensitivity, compensated thermal lag and faster MDSC capability for making these determinations TA 309

19 REFERENCES 1. Assignment of the Glass Transition, Special Technical Publication 1249, R. J. Seyler (Ed.), American Society for Testing and Materials, West Conshohocken, PA, L. E. Waguespack and R. L. Blaine, Design of a New DSC Cell with Tzero TM Technology, Proceedings of the 29 th Conference of the North American Thermal Analysis Society, 2001, pp R. L. Danley and P. A. Caulfield, DSC Resolution and Dynamic Response Improvements Obtained by a New Heat Flow Measurement Technique, Proceedings of the 29 th Conference of the North American Thermal Analysis Society, 2001, pp R. L. Danley and P. A. Caulfield, DSC Baseline Improvements by a Heat Flow Measurement Technique, Proceedings of the 29 th Conference of the North American Thermal Analysis Society, 2001, pp X. Quan, H. E. Bair and G. E. Johnson, Macromolecules, 1989, 22, p KEY WORDS differential scanning calorimetry, glass transition, heat capacity, modulated differential scanning calorimetry, thermoplastic polymers TA 309

20 TA INSTRUMENTS United States, 109 Lukens Drive, New Castle, DE Phone: Fax: Spain Phone: Fax: United Kingdom Phone: Fax: Belgium/Luxembourg Phone: Fax: Netherlands Phone: Fax: Germany Phone: Fax: France Phone: Fax: Italy Phone: Fax: Sweden/Norway Phone: Fax: Japan Phone: ) Fax: Australia Phone: Fax: steve_shamis@waters.com To contact your local TA Instruments representative visit our website at TA 309

21 New approach to characterize starch dispersions A.J. Franck, TA Instruments Keywords: Starch, gelatinization, starch cell, heating/cooling cycle, pasting, viscoelasticity Scope Starch is a natural product already known to the Romans as food thickener. Wolfgang Oswald was first to measure the viscosity of starch during the pasting process. And starch is not only a food product, functionally modified starches are widely used in the industry including adhesives, paper coatings, wood, packaging, pharmaceutical, and many other. Because of the specific nature of starch, rotational rheometers with viscometric test geometries (concentric cylinders, cone-plate) are not really suitable for testing starch suspensions. Starch dispersions require continuous mixing during the measurement to prevent sedimentation of the starch granules. Therefore instruments for characterizing starch (for example the amylograph) measure the torque of a mixing element to follow the changes during gelatinization. In order to allow a systemic analysis and a more fundamental rheological characterization, a mixing chamber (starch cell) has been mounted on a sensitive rheometer. Standard rheological methods based on steady, transient and oscillatory measurements are available now to evaluate starch during the gelatinization process as well as the final product. 1. Introduction The gelatinization process of starch dispersions is characterized using torque rheometers. The first instrument of this kind is the amylograph, consisting of a temperature controlled mixing chamber. The torque introduced into the material via the mixing element is a measure of the viscosity. Instruments like the RVA (Rapid viscosity analyzer) are optimized mixing devices to determine the gelatinization as well as the retrogradation of native and modified starch products. During a heating/cooling cycle, the angular velocity is maintained. The viscosity is calculated as the Newtonian equivalent based on a calibration with a standard material. Since starch dispersions are non-newtonian fluids and as such shear rate dependent, this viscosity calibration is certainly not adequate for more fundamental testing. Another issue is the control of the water content during the heating/cooling cycle. The new Starch Pasting Rheometer SPR, with builtin pasting cell, and Smart Swap TM Starch PAsting Cell, SPC, are designed to minimize the water losses during the cooking cycle. Mounted on a sensitive rheometer and separately calibrated for stain (rate) and stress, the starch cell provides a more accurate and powerful tool to characterize the gelatinization of raw and modified starch products as well as the properties of the starch gels. 2. What is starch Starch is abundant in nature. All major agricultural crops contain starch. Modern technologies enable starch to be extracted with high yield from agricultural crops. The extracted starch granule is a compact package of pure glucose polymer. Starch is composed of two polymers - amylose and amylopectin. Amylopectin is a branched chain polymer with branches of 20 to 30 glucose residues long. Amylose is a linear polymer with glucose residues of 400 to 4000 units long. Within the granules the starch molecules are layered down in an organized manner. In order to withstand modern processing and storage conditions as well as to provide special functionality to the end product, native starch is chemically or physically modified. The modifications include mild degradation, cross-linking of chains, derivatization with phosphate or esters, pregelatinization, etc. The addition of chemical groups to the starch chain for example, improves the clarity and stability of the gel during cooking, mixing and freezing. Starch molecules become tailor made hydrocolloids which go into food products, are used as coating for paper, as adhesive for paperback, etc. 1

22 3. Why test starch - the significance of the pasting Viscosity [AU] Peak viscosity Final viscosity Pasting temperature Holding strength Temperature [ºC ] The cooked starch exhibits a non-newtonian behavior characterized by an intensive shear thinning. Most starches also show a reduction of viscosity over time as a function of shear rate (thixotropy). As such, there is no absolute measure of starch viscosity. Rates of heating and cooling, holding time, shear rate etc. affect the final viscosity. Standard test protocols are therefore required and used to compare test results. 4. The Starch Pasting Rheometer (SPR) and Starch Pasting Cell (SPC) 0 0 Time [min] 15 0 Figure 1: Generalized Pasting Curve curve Raw starch exists as microscopic granules. The size and shape of these granules is characteristic of the starch s botanic source. When starch is heated above a critical temperature, the starch granules undergo a irreversible process, known as gelatinization. The properties of the starch gels depend on the origin of the raw starch (crop, potatoes, etc.), the environmental conditions (seasons) or the modification. The viscosity curve (pasting curve) produced by heating and cooling starch generally has a similar characteristic shape as shown in figure 1. Unmodified raw starch is insoluble in water below 50ºC. Early in the pasting process, the starch granules absorb a large amount of water and swell to many times their original size. The viscosity increases because the swollen starch granules have to squeeze past each other. Oswald has defined the temperature at the onset of the rise in viscosity as the pasting temperature. With increasing temperature, the granules rupture and amylose leaches into solution followed by amylopectin. Granule rupture and polymer alignment due to mechanical shear reduces the viscosity. This process that follows the gelatinization is known as pasting. The peak temperature occurs at the equilibrium point between swelling and polymer leaching. During a hold period (typically 95ºC) the viscosity drops to a minimum value, referred to as holding strength or hot paste viscosity. As the starch mixture is subsequently cooled, re-associations between starch molecules occurs. This usually causes the formation of a gel and the viscosity increases to a final viscosity. This phase of the pasting curve involves retrogradation or re-ordering of the starch molecules. The final viscosity is the most commonly used parameter to define the quality of a particular starch sample. Figure 2: Starch Pasting Cell (SPC) The cell on the SPR and the SPC are temperature controlled using resistive elements placed concentrically to the cup for heating. Cooling is through water carried in a helical conduit in close proximity to the cup outer walls. The maximum temperature ramp rate is 15ºC per minute, the maximum cooling rate is 30ºC per minute. Figure 2 shows a cutaway drawing of the starch pasting cell attachment. The impeller is designed to closely fit the cup containing the starch suspension. The top of the mixing element shaft is gradually extended to provide a noncontact conical shape cover, which significantly prevents solvent evaporation. Since the impeller produces an illdefined flow, analytically derived factors used in the conversion of the angular velocity to shear rate and torque to shear stress do not exist. For Newtonian materials, the mixer geometries can be simply calibrated for the viscosity using a reference material. For non-newtonian fluids like the starch suspensions this is not possible and separate calibration constants for stress and strain (rate) need to be determined. A procedure for a quantitative analysis of torque and rotor speed data to extract viscosity shear rate 2

23 curves using non conventional geometries has been described by Ait-Kadi, Marchal, et al using a Couette Analogy for mixer elements. Once strain(rate) and stress geometry coefficients are determined for a given geometry, standard test protocols based on continuous rotation or oscillatory testing can be used to measure the viscosity as a function of shear rate or the dynamic moduli as a function of the frequency. 5. Test results Figure 3 shows two runs of a heating/cooling cycle for a waxy maize cook-up starch (ST01) and figure 4 two runs Temperature [ºC] rezista0022 [Pas] rezista0023 [Pas] Time [s] Viscosity [Pas] tests were performed at a rotation speed of the impeller of 160 rpm. The two pasting curves exhibit the typical shape characteristic for the two different types of starch. The final viscosity for the two starches is very similar, also the pasting curve is quite different. The reproducibility of the tests is excellent. The temperature plot does not show a sharp change between the steps. This is due to the temperature sensor, positioned close to the cup wall to reflect the sample temperature better. The curvature in the heating ramp for the hydroxyethylated dent corn starch could be an indication of a slight exothermal during the starch cooking. In order to check the evaporation of water in the new starch cell, a series of experiments was conducted using the waxy maize cook-up starch (Rezista), where evaporation is more of a problem. Figure 5 shows four plots, obtained with different impeller systems. Run #1, with the highest viscosity profile, was done with an impeller with no rim to give worst-case evaporation scenario. The middle runs (Run #2& #3) were done with a Staley paddle at two different gaps. The Run #4 was performed with the TA geometry shown in figure 2. The lower viscosity corresponds to the lowest moisture loss, which has been obtained for the TA starch cell with a tight gap between impeller and cup. The conical design of the impeller makes Figure 3: ST01 Waxy Maize Cook-up starch for a hydroxyethylated Dent Corn Starch (ST03). Cook-up starches are used widely as thickeners and stabilizers in products such as gravies, soups, dairy products, etc. All Temperature [ºC] run #1[Pas] run #2[Pas] run #3[Pas] run #4[Pas] 2 1 Viscosity [Pas] slight exotherm ethylex0010 [Pas] ethylex0019 [Pas] Time [s] Temperature [ºC ] Time [s] Figure 4: ST03 Hydroxyethylated Dent Corn Starch Viscosity [Pas] Figure 5: Pasting curves obtained with different impeller arrangementgs to study the effect of water evaporation evaporation less dependent on the vertical position. The moisture loss for run #4 was 0.7 as opposed to 1.15 & 1.7g using the Staley paddle arrangement in run #2& #3. Figure 6 and figure 7 show data obtained on the same two starch samples, however the steady shear has been stopped at 75ºC and the test was continued at an applied oscillating torque of 10 µnm. Under these conditions, the sample is experiencing negligible shearing. The complex viscosity is recorded to follow the gel formation during the 3

24 Dynamic Moduli [Pa] Time [s] G' [Pa] G'' [Pa] Figure 6: Storage and viscous modulus G, G for the waxy maize cook-up starch during pasting cooking cycle. Plotted are the G and G respectively. The storage modulus G of the waxy maize starch is considerable higher then the storage modulus of the hydroxyethylated dent corn starch, whereas the final viscosity under continuous shear conditions (figure 3 and 4) was approximately the same for both starches. The storage modulus of the waxy maize starch is higher than the viscous modulus throughout the heating and cooling phase and a gel like behaviour already established early in the pasting process. It may be concluded, that the continuous shearing in the standard pasting procedure affects the gel structure build-up differently for the two types of starches Temperature [ºC] 6. Conclusion The starch cell is an option for the AR2000 with excellent T-control during the heating and cooling cycle. The new design of the impeller minimizes moisture losses. The integration of the cell with a sensitive rheometer, allows in addition to conducting standard heating/cooling cycles, more advanced rheological characterization of the starch gels using oscillatory testing protocols. The evaluation of strain(rate) and stress coefficients provides an analysis in terms of correct shear rate and stress while using a mixing element to measure torque and not an ideal viscometric flow geometry typical for rotational rheometers. 7. References Quantitative Analysis of Mixer type rheometers using Couette analogy A. Ait-Kadi, P. Marchal, et al, Canadian J. Chem. Eng., 80, 2002 American Association of Cereal chemists (AACC) Method Use of a mixer geometry to determine the viscosity and linear viscoelastic properties of starch B. Costello, Proc. 3 rd Int l Symp. On Food Rheology and Structure, G' [Pa] G'' [Pa] Dynamic moduli [Pa] Temperature [º C] Time [s] Figure 7: Storage and viscos modulus G, G fr the hydroxyethylated dent corn starch during pasting 4

25 FINANCING APPLICATION To help us process your application as quickly as possible, please fill out this application completely. Please provide a copy of your quotation or product proposal, if applicable. Please fax completed application to (888) For more information please call 1(800) GE Vendor Financial Services 10 Riverview Drive Danbury, CT (800) FINANCING TRANSACTION OVERVIEW Equipment Description: New Used Upgrade Equipment Cost: $ Total Financed Amount: $ Term: Other Purchase Option: FMV $1 10% Other Deliver Documents to: Sales Rep Customer Delivery Method (if , be certain to fill in appropriate line): FedEx Fax COMPANY AND BILLING INFORMATION FLEXIBLE FINANCIAL OFFERINGS Full Legal Name: Federal ID #: DBA Name: Business Phone: ( ) Contact Name: Address: Phone: ( ) Fax: ( ) Equipment Location (# & Street): City: State: Zip: Billing Address (# & Street): City: State: Zip: (If different than equipment location) Type of Business: Corporation Partnership Proprietorship Non-Profit Sub S Municipality LLC LLP Time in Business: State of Incorporation: Organizational ID#: Exempt from State Sales & Use Tax : Yes No (if exempt, please attach sales tax exemption certificate) REFERENCES Primary Bank: Contact Name: Phone :( ) Checking Account #: Loan Account #: For transactions > $100,000, please include the last 2 years financial statements and the interim financial statement for the most recent period PRINCIPAL S INFORMATION (FOR PRIVATELY HELD COMPANIES ONLY) Principal: State of Residence: Social Security # Ownership %: # Years Industry Experience: Principal: State of Residence: Social Security # Ownership %: # Years Industry Experience: Principal: State of Residence: Social Security # Ownership %: # Years Industry Experience: AUTHORIZATION FOR DISCLOSURE OF CREDIT INFORMATION & INFORMATION REQUIREMENTS Applicant hereby authorizes the release of business and/or personal credit information to (1) General Electric Capital Corporation, its successors and assigns, from any source including credit bureau reporting agencies and Applicant's bank for the purpose of extending credit, (2) Any purchaser or potential purchaser of General Electric Capital Corporation's interest in this application and any resulting agreement between Applicant and General Electric Capital Corporation, and/or (3) any credit reporting agency. Applicant hereby represents all information contained in this application and authorization is true, correct and complete. A photostatic copy of this application and authorization shall be valid as the original. Signer represents and warrants that he or she is authorized to execute this authorization and release regarding credit information on behalf of the Applicant. Applicant hereby authorizes General Electric Capital Corporation to execute and file any UCC financing statements in its name upon approval of the application. Authorization to Obtain Consumer Credit Report: By signing below, each undersigned individual, who is either a principal of Applicant or a personal guarantor of its obligations, provides written instruction to General Electric Capital Corporation or its designee (and any assignee or potential assignee thereof) authorizing review of his or her personal credit profile from a national credit bureau. Such authorization shall extend to obtaining a credit profile in considering this application and subsequently for the purposes of update, renewal or extension of such credit and for reviewing or collecting the resulting account. A photostatic or facsimile copy of this authorization shall be valid as the original. Signature: X Date: Signature: X Date: (Authorizing Officer Signature) (Authorizing Officer Signature) Name: Title: Name: Title: (Please Print Here) (Please Print Here) The Federal Equal Credit Opportunity Act prohibits creditors from discriminating against credit applicants on the basis of race, color, religion, national origin, sex, marital status, age (provided the applicant has the capacity to enter into a binding contract), because all or part of the applicant s income derives from any public assistance program, or because the applicant has in good faith exercised any right under the Consumer Credit Protection Act. The federal agency that administers compliance with this law is the Federal Trade Commission, Equal Credit Opportunity, Washington, DC If your application for business credit is denied, you have the right to a written statement of the specific reasons for the denial. To obtain the statement, please contact Operations Manager, General Electric Capital Corporation, 10 Riverview Drive, Danbury, CT 06810, or call (800) within 60 days from the date you are notified of our decision. We will send you a written statement of reasons for the denial within 30 days of receiving your request for the statement. PLEASE FAX COMPLETED APPLICATION TO FOR MORE INFORMATION CONTACT YOUR LOCAL TA INSTRUMENTS REPRESENTATIVE

26 BENEFITS OF LEASING Regardless of the lease product you choose, leasing offers a variety of benefits that can help you grow your business. PROVIDES UP TO 100% FINANCING VFS finances up to 100% of your equipment costs. In addition to your hardware, VFS can finance your software, installation, training and service contracts. FINDING THE RIGHT LEASE PRODUCT VFS can help you determine the best lease solution for your needs. Here s a brief overview of the products we offer. If you don t see what you need, call your leasing professional to find a lease product that is right for you. Lease Product End of Lease Options Benefits WHY LEASE? Rheometers...Thermal Analysis Systems... regardless of product type, leasing is a fast, easy way to acquire the equipment you need now! CONSERVES CASH Lease financing allows you to take cash normally reserved for equipment purchases and use it for higher-return opportunities or critical short-term needs such as seasonal working capital. Fair Market Value Purchase Option Purchase equipment at fair market value Renew lease Return equipment Lowest monthly payments Ability to upgrade as technology changes Tax deductible payments* When you lease, you can stay current with advancing technology while maintaining affordable payments. Plus, you ll lighten your purchasing burden and conserve your working capital, which will help your business grow! WHY LEASE WITH GE VENDOR FINANCIAL SERVICES? GE Vendor Financial Services (VFS) is a worldwide leader in providing specialized equipment financing. Staffed with experienced leasing professionals, VFS can create a flexible financing solution that meets your needs and makes it simple for your business to upgrade or add equipment. Backed by the financial strength and resources of GE, VFS is a reliable financing source that provides the stability and expertise you need. CARRIES LOW MONTHLY PAYMENTS You can improve your cash flow with low monthly lease payments. VFS offers a variety of customized payment structures to meet your specific financial requirements. PRESERVES CREDIT LINES When you finance with VFS, your existing bank credit lines are preserved. This allows you to save those critical lines for other strategic business opportunities. OFFERS CONVENIENCE Leasing is easy and convenient. The fixed, low monthly payment amount covers everything. Payments are simple to budget and multiple purchases may be consolidated into one invoice. DELIVERS THE BENEFITS OF THE MOST 10% Fixed Purchase Option $1 Purchase Option Municipal Purchase equipment for 10% of the original equipment cost Renew lease Return equipment Purchase equipment for $1 Purchase equipment for $1 End-of-term flexibility Lower payments than the $1 Purchase Option Lease Depreciation benefits* Predictable purchase option price Equipment ownership at end of lease term Depreciation benefits* Low monthly payments Equipment ownership at end of lease term Tailored pricing and structuring for qualified state and local entities TA INSTRUMENTS AND GE VENDOR FINANCIAL SERVICES TWO WORLD LEADERS WORKING TOGETHER TO PROVIDE CUSTOM FINANCIAL SOLUTIONS ADVANCED TECHNOLOGY TODAY Don t delay acquire this innovative technology now! By leasing through VFS, you can defer your purchasing decision to the end of the lease when you are better positioned to assess both your company's equipment needs and the technological conditions in the marketplace. All leases subject to GE Vendor Financial Services credit approval. *Consult your tax or legal advisor regarding potential benefits VFS ALSO OFFERS QUALIFIED CUSTOMERS A VARIETY OF CUSTOMIZED LEASE STRUCTURES Zero percent financing Deferred payments Unique term lengths

27 Competitive Strategy? I ve Got It!!!!! Lets just lower prices and SAY we are as good as TA Instruments! I can t believe it s come down to this! Follman

28 Training Courses TA Instruments conducts a wide variety of training courses around the world. For more information on courses in your area click on the appropriate link below. North America Europe HOME

29 Theory & Applications Training Courses The TA Instruments Thermal Analysis and Rheology training courses (lecture-based) are designed to familiarize the user with applications, method development, and operating techniques of our thermal analysis and rheology instrumentation. Each course is specific to a particular technique and costs $400 per person, per day. New system purchases will include a waiver for one free class per instrument purchased. Typically, these courses should be attended within 3-6 months of purchase and assume the customer knows how to operate the instruments. To register visit (U.S. only) Certified User Training Courses The first in a series of Certified User Training Courses was held in March, and proved popular with the attendees. It represents the latest in our efforts to help our customers achieve a higher level of expertise. The course is designed for you to get the most from your DSC instrument. It is composed of four sections taught by our knowledgeable applications staff. These minutes sections will each cost $300, and consist of: DSC - Theory DSC - Calibration & Maintenance DSC Method Development DSC Data Interpretation An exam will be given at the end of each section. Upon passing all four sections, a Certificate will be issued stating that you have completed TA Instruments Certified DSC program. This certificate will be good for 2 years from the date of issuance. The next DSC Certified User Course is scheduled for June 18-19, Click here to register now for Live Courses. Theory and Applications Customer Training Course TA Instruments offers a continuing series of theory and applications training courses relating to thermal analysis and rheology. They are held regularly in Delaware. The courses are technique specific. Those wishing to attend any of them may view the schedule and register on line at the Support section at Link to U.S. Course Schedule e-training Courses If you, or your staff, need training but your schedule, or budget, doesn t permit you to visit Delaware, consider visiting our website and registering for our convenient e-training Courses. For a modest fee, you can take one or a series of them in the convenience of your location. All you need is a computer and telephone line. Click Here For Details On-Site Training Have one of our thermal or rheology experts provide training at your site. If interested, contact Louis Waguespack at or by at lwaguespack@tainst.com. Additional Training Courses May 7-8, 2003, Western Kentucky University Materials Characterization Center Thermal Analysis Short Course, a hands on DSC and TGA Training Course, "Using DSC and TGA for Characterizing Polymers and Pharmaceuticals". For more information and to download the course registration click here. June 8-13, 2003, University of Minnesota Rheological Measurements Short Course, Application to Polymers, Suspensions, and Processing, directed by Christopher W. Macosko. For details please visit HOME

30 Tech Talk This section provides technical notes, application briefs, helpful hints, and specific information on the use of thermal analysis and rheology instrumentation. The goal is to help you get the maximum value from your TA Instruments equipment. Technical Documents Available for easy download are a series of technical notes and applications briefs relating to various topics in thermal analysis and rheology. Thermal Analysis 1. Common PID Settings (TN049a) 2. ISO Thermal Methods (TN 46b) 3. ASTM International Thermal Methods (TN 21j) A list of American Society for Testing and Materials International (ASTM) standards that use thermal analysis or rheology 4. Weight Loss Determined from Mass Spectrometry Trend Data in a Thermogravimetric/ Mass Spectrometer System (TA306) Rheology 1. Using the DMA Q800 for ASTM International D 648 Deflection Temperature Under Load (RH086) 2. The Use of Low Shear-Stress Rheological Data in Settling of Particles in Paints (RH083) HINTS In DMA when performing a dynamic instrument calibration, you are asked to first load the compliance steel sample. Following this, you are prompted to load the thinner steel calibration samples one after another. To assure that the thin, flexible calibration samples are properly aligned, you may first reload the compliance steel, finger-tightening the fastening screws with the bearing in the floating mode. The bearing may then be locked, the compliance steel sample removed. and the thin calibration sample loaded torquing the fastening screws to 10 in-lb. This will ensure that the flexible steel is mounted straight. Thanks to Sujan Bid Wadud of TA Instruments for this Hint Occasionally, one wants to operate a thermal analysis module in a low moisture or oxygen environment. The quickest and least expensive way to do this for a few samples is by putting the module in a dry bag. These are available from a number of vendors but we get ours from Aldrich (Milwaukee, WI). Be sure to get a size that is big enough for the whole instrument and still leave room for sample manipulations through the glove holes. Thanks to Roger Blaine of TA Instruments for this Hint Today, most rheometers are equipped with the peltier plate system, because of its excellent temperature control, and fast response, for heating and cooling. Here are some tips to keep your peltier system (plate and circulator / water bath) in top condition. 1: Water baths - Keep the reservoir at least three quarters (3/4) full. Since the water provides heat exchange fluid for the peltier plate, this step allows enough volume in the bath to maintain the system as close as possible to ambient temperature. 2: Clean Water Water in the bath should be clean, since dirt build up could clog the peltier water line. Change the water if it appears dirty. Oil in the water indicates that the pump is leaking. If so, contact TA Service to check if a replacement pump is necessary. 3: Water Conditioner (PN ) this is recommended to condition the water in the bath, and prevent bubbles, and algae development. 4: Peltier plates used at high temperature (above 100 C) - Peltier plates operated above 100 C should be fed by a temperature controlled water circulator by running tap water. 5: Water lines should not leak If this occurs, changing of tubing or fittings may be necessary. 6: Good water flow This is important for good peltier system performance. The return water line from the Peltier plate to the bath, circulator, or drain (in case of running tap water) should have good flow. Make sure that water lines are not dirty or clogged. Low flow conditions will trigger a Peltier Overheat alarm, and may result in damage to the peltier plate. Thanks to Gerry Schnur of TA Instruments for this Hint REWARDS FOR HINTS This HINTS section, with its suggestions on how to do better or easier thermal analysis and rheology, has proven to be very popular. So we are looking for even more HINTS to pass along. Do you have one that you would like to offer? Send it to us and if we use it, we ll send to you a FREE TA shirt and pen. Send your hints to rblaine@tainst.com. HOME

31 Worldwide Technical Seminars TA Instruments is currently presenting a series of technical seminars on thermal analysis and rheology throughout the USA, Europe, and Japan. For the schedule, dates, cities, locations, and registration information, please visit our website ( The program emphasizes technical aspects of materials characterization, with sessions on measurement of the glass transition, melting and crystallization, reactions and processes, and physical properties. The applications will be multidisiplined, and will feature the optimum use of the entire thermal and rtheological techniques to best solve a material characterization problem. Registrations are already at record levels, but there is still time and space for any customer or prospect interested in attending SEMINAR SERIES HOME THERMAL ANALYSIS & RHEOLOGY

32 Rheology Advantage Software A new release of Advantage Rheology software (V 4.1) offers not only significant enhancements to our AR 2000 Mobius Drive technology (see below), but also data presentation improvements for all AR Series instruments (AR 2000, AR 1000, AR 550, AR 500). Updated versions of Rheology Advantage Navigator and Enhanced Polymer Library software are also available. Rheology Advantage V 4.1 software is free of charge to all existing AR Series Advantage software users, as are Navigator and the Enhanced Polymer Library if previously purchased. Download the form (RA4.1 .doc), complete it, and return it by to TA Instruments. You will also have the opportunity to order the Navigator and Polymer Library if you do not currently own them. Note: The CD containing the above software also includes the current Advantage Thermal Analysis Software. HOME

33 Updates Pittsburgh Conference North American Conferences and Exhibitions The 2003 Pittsburgh Conference held at the Orange County Convention Center, Orlando (FL, USA) from March 9-14, 2003 was a successful exhibition for TA Instruments, as judged by the very high level of quality leads uncovered during the four day exhibition. An expanded (600 sq.ft.) booth effectively displayed our full complement of leading Q Series thermal modules (Q1000, Q500, Q600, Q400, Q800), and Rheometrics Series rheometers (AR 2000, ARES, and RSA III). Many customers complemented the professionalism, and technical competence of our staff at the exhibit. ACS National Exposition This conference was held at the Morial Convention Center, New Orleans (LA, USA), from March 24-26, TA Instruments displayed our Q Series DSC and AR 2000 Advanced Rheometer. Upcoming Conferences A selected listing of conferences that should interest thermal analysis and rheology users is shown below. TA Instruments will be participating as lecturers and / or exhibitors showing our latest thermal analysis and rheology products. For more information on European conferences contact our specific country contacts. Exhibits/Conferences Pressure Sensitive Tape Council Conference: May 7-9, 2003 Washington Hilton & Towers, Washington, DC, USA. Please visit our booth, if you plan to attend. For more information on the conference, or to register on-line, visit: National Plastics Exposition Conference: June 23-27, 2003 McCormick Place, Chicago, IL, USA. Please visit our booth #10131, if you plan to attend. For more information on the conference, or to register on-line, visit: Institute of Food Technologies Conference: July 13-16, McCormick Place, Chicago, IL, USA. Please visit our booth #4668, if you plan to attend. For more information on the conference, or to register on-line, visit: ACS National Conference Conference: September 8-10, 2003 Jacob Javits Convention Center, New York, NY, USA. Please visit our booth #255, if you plan to attend. For more information on the conference, or to register on-line, visit: NATAS Conference on Thermal Analysis & Applications Conference / Short Course: September 20-24, 2003 Albuquerque Hilton Hotel, Albuquerque, NM, USA. Please visit our booth, if you plan to attend. For more information on the conference, or to register on-line, visit: Society of Rheology Conference / Short Course: October 12-16, 2003 Pittsburgh, PA, USA. Please visit our booth, if you plan to attend. For more information on the conference, or to register on-line, visit: societyofrheology.org AAPS Annual Meeting Conference: October 26-30, 2003 Salt Palace Convention Center, Salt Lake City, UT, USA. Please visit our booth, if you plan to attend. For more information on the conference, or to register on-line, visit: International Coatings Exposition Conference / Exhibition: November 12-14, 2003 Pennsylvania Convention Center, Philadelphia, PA, USA. Please visit our booth, if you plan to attend. For more information on the conference, or to register on-line, visit: HOME

34 New Staff at TA Instruments We are pleased to announce Wei Xie as our new Applications Engineer in our Chicago Office. Wei holds a Ph.D. degree in analytical/polymer chemistry. As a material scientist and analytical chemist, he has 10 years of R&D experience and 12 years of hands-on experience with thermal analysis instruments. He has strong research background in development, synthesis, and characterization of polymeric materials. He has been actively involved in the thermal analysis professional society and was the Conference Chairman of the 2002 North American Thermal Analysis Society Annual Conference. He has more than 50 publications in the interdisciplinary areas of thermal analysis and material science. HOME

35 New Product Introductions TA Instruments is committed to providing our customers with the latest technology. Highlighted below are new products and accessories now available: Advantage Integrity Archiving TA Instruments has issued an upgrade to our Advantage Integrity software that provides additional support for Integrity s archiving capability. Advantage Integrity is designed to enable customers to meet the requirements of the US Food and Drug Administration as expressed in their Title 21-CFR 11 regulations. New Starch Pasting Rheometer and Starch Pasting Cell TA Instruments introduces the Starch Pasting Rheometer (SPR) and Starch Pasting Cell (SPC); two new products in the Rheomertrics Series of rheometers focused on improving the characterization of starches. Starches are natural products most extensively used as a thickening agent in the food industry, but also used widely in the adhesives, paper coatings, wood, packaging, and pharmaceutical industries. A fundamental rheological measurement conducted routinely on starches is evaluation of the gelatatinization process. This is accomplished by measuring the viscosity of the starch suspension while heating and cooling under specific testing conditions. The resultant curve, referred to as the pasting curve, yields important starch performance parameters including the pasting temperature, peak viscosity, holding strength, and final viscosity. The traditional viscometric test geometries, such as cone and plate, parallel plate, and concentric cylinders, are not well suited for starch characterization because these dispersions require continuous mixing during the measurement to prevent sedimentation of the starch granules. For this reason, the instruments that have been used for characterizing starch (for example the amylograph and RVA) measure the torque of the mixing element in a mixing chamber to follow the changes during gelatinization. To enhance the quality of starch measurements, TA Instruments has improved the design of mixing chamber to minimize moisture loss (which is also of concern during measurements) and have mounted it onto our highly sensitive AR Series Rheometers, which allows for a systemic analysis and rheological characterization. Standard rheological methods based on steady, transient and oscillatory measurements are now available to evaluate starch during the gelatinization process as well as in the final product. A stand-alone instrument, the Starch Pasting Rheometer (SPR), based on TA Instruments AR1000 technology is available. The SPR, combined with Rheology Navigator scripted software, makes it an ideal low-cost solution for enhanced routine quality control evaluation of starches. Also available is the Starch Pasting Cell, a Smart Swap option for the world s best selling research grade AR2000 Rheometer. A cross-section of the pasting cell is shown with the impeller in place. Heating is through resistive elements placed concentrically to the cup. Cooling is through water carried in a helical conduit in close proximity to the cup outer walls. Flow is controlled through relays placed upstream of the cup. Maximum temperature ramp heating rate is 15 C per minute and cooling rate is 30 C per minute. The temperature is read by a Pt 100 probe in close thermal contact with the cup bottom. For a more detailed technical description on how the SPR and SPC can help with your starch pasting measurements and more, see the attached article titled New Approach to Characterize Starch Dispersions. For more information on these products, please contact Russell Ulbrich, Product Manager Rheology, at (302) or at rulbrich@tainst.com. HOME

36 NEW BROCHURES Click on the cover to download a brochure OVERVIEW RHEOLOGY DSC TGA DMA TMA Training Brochure Applicable in U.S. Only 2003 Parts and Accessories Price Guide HOME

37 For your FREE poster Rheology Poster Thermal Analysis Poster DMA Poster Polymer Reference Card HOME