Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound

Transcription

1 Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound J.P.D. Alves 1, E. Hage Jr. 1, A. Rodolfo Jr. 2, R. Gonçalves 3 1 Federal University of São Carlos, Brazil; 2 Braskem S/A, Brazil; 3 State University of Campinas, Brazil

2 Agenda Overview of Braskem S/A Overview of the NEO PVC Program Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound

3 Agenda Overview of Braskem S/A Overview of the NEO PVC Program Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound

4 Braskem Global Petrochemical Player Gross Revenue Net Revenue EBITDA US$ 12.3 bi US$ 9.7 bi US$ 1.6 bi Exports Assets US$ 2.3 bi US$ 11.7 bi Note: Pro forma basis for 2007, with full consolidation of Ipiranga and Copesul. Source: Braskem

5 Large scale coupled with increased competitiveness 3rd largest producer of resins in the Americas 5, , ,250 * 515 2,906 2,728 PVC PP PE 4,348 3, ,975 1, ,593 2,152 1, Dow Exxon Braskem Formosa Equistar Chevron Nova Petroquímica 3 rd 13 th 2 nd highest EBITDA margin in Global Petrochemical Industry 40% 30% 20% Braskem 17% 10% 0% Sabic Reliance Nova Dow Westlake Chemicals * includes 160 k ton of PE from Petroquímica Triunfo Source: Braskem Companies info as of 2007 (Sabic as of 2006). Georgia Gulf

6 Leadership in the Brazilian market PE % PP % 32% 52% 37% 49% 16% OTHERS 14% PVC % IMPORTS Resins % 27% 19% 54% 32% 16% 52% Source: Braskem/Abiquim Dec 07

7 Innovation and Technology as key value drivers Over US$ 160 million in R&D assets 200 researchers 8 pilot plants 187 patents filed Focus on nanotechnology and intelligent packaging 18% of resins sales derive from products launched in the last three years Partnership with universities and R&D centers in Brazil and abroad Source: Braskem

8 Agenda Overview of Braskem S/A Overview of the NEO PVC Program Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound

9 NEO PVC Concept ( Núcleo de Estudos Orientados do PVC PVC Oriented Studies Network, started 2005 NEO PVC is a mutidisciplinar network of researchers in the Academia and/or R&D centers in Brazil Coordinated by Braskem Its action is planned, oriented and integrated to the company s objectives Its focus is on the generation and propagation of technologies for the application of PVC Braskem supports the project through the resources of its Vinyls Technology & Innovation Center in São Paulo

10 NEO PVC Objectives Main: Development of a culture of academic research on PVC technologies in Brazil Generation of technological innovations Reinforce Braskem s position as a reference in the technology of PVC application in Brazil

11 NEO PVC Objectives Main: Development of a culture of academic research on PVC technologies in Brazil Generation of technological innovations Reinforce Braskem s position as a reference in the technology of PVC application in Brazil Additional: Development of specialized human resources for the PVC industry Creation and diffusion of knowledge Strenghtening of the relationship with the Academia and its members Renovate PVC as a versatile, modern and environmentally safe material

12 NEO PVC pipeline of research projects # Title Academia Main focus Estimated date of conclusion S2/07 S1/08 S2/08 S1/09 S2/09 S1/10 1 PVC gelation assessment UFSCar Blends/composites 2 PVC/CPVC pipes for sprinklers USP Sustainability 3 PVC/glass fiber composites USP Blends/composites 4 In situ vulcanization of PVC/NBR blends UFSCar Blends/composites 5 Plastisol nanocomposites USP Nanocomposites 6 Plasticisation of PVC with biodegradable polymers UFSC Blends/composites 7 Biodegradable PVC compounds USF Blends/composites 8 Reinforcement of PVC with banana tree fibers Sociesc Blends/composites 9 Reinforcement of PVC with glass fibers UFSCar Blends/composites 10 Preparation of Brazilian organoclays UFSCar Nanocomposites 11 Carbon nanotube nanocomposites UFSC Nanocomposites 12 Low smoke PVC compounds UNICAMP Nanocomposites 13 PVC gelation assessment with ultrassound UFSCar Blends/composites 14 In situ vulcanization of PVC/NBR blends scale up UFSCar Blends/composites

13 Agenda Overview of Braskem S/A Overview of the NEO PVC Program Analysis of the S-PVC gelation process: determination of the degree of gelation using DSC and ultrasound

14 Objectives of the project Master degree dissertation presented in December 2007 by Juliana Alves in the Federal University of São Carlos Materials Enginnering Department Main objectives: Comprehension and study of the PVC gelation process Quantify the degree of gelation using differential scanning calorimetry, understanding this technique As a consequence of the main objectives, evaluate ultrassound analysis as na alternative method for the evaluation of the degree of gelation of PVC compounds

15 Background During the processing S-PVC resins or compounds gelates/fuses when heated and sheared Operation conditions and thermomechanical environment during processing modifies the initial granular particles The identity of the grains, primary particles and primary crystals is destroyed during gelation and fusion After fusion and cooling secondary crystallinity is formed MARQUES, P.R.; COVAS, J.A. Processing characteristics of U-PVC compounds Companhia. Ind. de Resinas Sintéticas, Cires, S.A

16 Backgound Allsopp (1982): The breakdown of PVC grains can only occur at the aggregates or primary particles level, whenever the material is subjected to very high shear stress, as it is the case with torque rheometers. In typical industrial equipment, the fusion mechanism involves Compaction, Densification, Fusion and Elongation of the PVC grains (CDFE mechanism), which means that: the main "flow unit" is the PVC grain initially, PVC grains are compacted and densified and their internal porosity is progressively eliminated as pressure and temperature rise, initiating an intra-granular fusion process Marques; Covas (2003) identified grain boundaries over a significant distance along the screws of an extruder Intragranular fusion and shear stress causes elongation in the flow direction ALLSOPP, M.W. Mechanism of Gelation of Rigid PVC during Processing. Imperial Chemical Industries Limited, MARQUES, P.R.; COVAS, J.A. Processing characteristics of U-PVC compounds Companhia. Ind. de Resinas Sintéticas, Cires, S.A

17 Background ALLSOPP, M.W. Mechanism of Gelation of Rigid PVC during Processing. Imperial Chemical Industries Limited, MARQUES, P.R.; COVAS, J.A. Processing characteristics of U-PVC compounds Companhia. Ind. de Resinas Sintéticas, Cires, S.A

18 Background MARQUES, P.R.; COVAS, J.A. Processing characteristics of U-PVC compounds Companhia. Ind. de Resinas Sintéticas, Cires, S.A

19 Background Summers model: Primary particles original morphology After cooling the secondary crystallininty is formed Primary particles partially gelled, showing the interdiffusion of the polymer chains SUMMERS, J. Journal of Vinyl and Additive Technology, 3, 130, FILLOT, L..A., et al. Journal of Vinyl and Additive Technology, 12, 98, 2006.

20 Background Assessment of PVC degree of gelation - DSC GILBERT, M.; VYVODA, J.C. Polymer, 22, 1134, 1981.

21 Background Assessment of PVC degree of gelation Cappilary rheometry ALVES, J. P. D.; RODOLFO JR., A. Polímeros, 16, 2006.

22 Background Assessment of PVC degree of gelation Dichloromethane (EN 580) or acetone (ASTM D2152) immersion test

23 Project First part: Understand the gelation process Analise the morphological changes during the gellation/fusion process through torque rheometry and scanning electron microscopy Assess the degree of gelation through DSC

24 Project Second part: Correlate acoustic properties (ultrassound) and degree of gelation assessed by DSC on PVC pipe samples taken from a customer Correlate mechanical properties obtained by acoustic methods (ultrassound) and conventional (tensile) methods

25 Experimental Part 1 Ingredient Ratio (pcr) Function of formulation Norvic SP 767 P 100 Suspension PVC Resin Naftosafe CZ ,8 Ca/Zn-based thermal stabilizer Barralev C 10 Calcium carbonate Calcium stearate 1 Internal lubricant

26 Results Part 1

27 Results Part 1

28 Results Part 1

29 Results Part 1

30 Results Part 1

31 Results Part 1

32 Results Part 1 Test temperature ( o C) DSC degree of gelation ,5% ,3% ,4%

33 Experimental Part 2 Pipe sample External diameter (mm) Mass temperature ( o C) Taken from a customer during machine setup

34 Experimental Part 2 Ultrassound generator Emmiting transducer Recepting transducer Pipe sampe E= Elastic modulus ρ = Density V = Velocity of propagation of the ultrassound wave

35 Results Part 2 Pipe sample DSC degree of gelation Mass temperature ( o C) Elastic modulus (ultrassound) (MPa) Shear modulus (ultrassound) (MPa) 1 48% % % %

36 Results Part Ultrassound elastic modulus (MPa) R 2 = 0, % 48% 50% 52% 54% 56% 58% DSC degree of gelation (%)

37 Results Part 2 Pipe sample DSC degree of gelation Elastic modulus (tensile) (MPa) Elastic modulus (ultrassound) (MPa)

38 Conclusions It was possible to monitor the morphological changes as well as to characterize the behavior of gelation and fusion Through DSC tests it was possible to obtain the degree of gelation of samples processed by Torque Rheometry at different testing temperatures, keeping a constant rotation. It is concluded that the processing temperature is closely linked to the degree of gelation The degree of gelation is correlated to the elastic and shear modulus obtained by ultrasound apparently, the higher the degree of gelation, the greater the value of the modulus Ultrasound seems to be a feasible technique to be further evaluated in order to be used to correlate the acoustic properties of the suspension PVC compounds with their degrees of gelation

39 Future work and perspectives Evaluate different types of transducers (longitudinal and transversal) and its influence on frequency and velocity of propagation Analise the influence of the formulation components on the velocity and modulus by ultrassound Correlate DCMT x DSC x ultrassound measurements of the degree of gelation on samples produced in a torque rheometer Develop ultrassound equipments for the on-line measurement of the degree of gelation

40 Thank you for your attention! Have a safe and pleasant trip back home! antonio.rodolfo@braskem.com.br