COMPARATIVE SDUTY OF POLYSTRYENE FOAM DEGRADATION IN THE OPEN-AIR AND ARTIFICIAL WEATHERING EXPOSURE

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1 COMPARATIVE SDUTY OF POLYSTRYENE FOAM DEGRADATION IN THE OPEN-AIR AND ARTIFICIAL WEATHERING EXPOSURE U. Meekum School of Polymer Engineering, Institute of Engineering, Suranaree University of Technology R. Kenharaj School of Environmental Engineering, Institute of Engineering, Suranaree University of Technology Polystyrene foam (PS foam) both without and with 1% Benzoyl peroxide coated were found to be exponentially degraded within 6 months under the open-air and artificial weathering exposure. The reaction mechanism of this foam was identified as chain scission. The peroxide was effectively used as photo accelerator. The experimental data and also the statistical hypothesizes analysis using t-test with the 95% degree of confidence suggested that the data obtained from the open-air and the ones from artificial weathering exposure were analogous. Published in ANTEC 2002, San Francisco, U.S.A.,

2 ROLES OF POLYPROPYLENE GLYCOL DURING SOLVENT-BASED LAMINATION OF CERAMIC GREEN TAPES Nitinat Suppakarn, Hatsuo Ishida, and James D. Cawley Department of Macromolecular Science and Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, Ohio, U.S.A. Solvent lamination of alumina green tapes is readily accomplished using a mixture of ethanol, toluene, and poly(propylene glycol), or PPG. After lamination, the PPG is clearly present as a discrete film at the interface between the laminated tapes, and direct particle-particle contact does not, in general, exist across the joined surfaces. This condition, however, does not generate delamination during firing. Instead, stacks of green tapes laminated using this mixture routinely sinter to full density and no evidence of original joint persists through the firing process. This paper presents the results of experiments undertaken to determine the role of PPG in the lamination process and, specifically, the mechanism by which it is redistributed during subsequent processing. PPG slowly diffuses through the organic binder film at room temperature. The PPG diffusion rapidly increases as the temperature is in creased to 80 o C. The key to the efficiency of adhesives during green-tape lamination is mutual solubility of the nonvolatile component of the glue and the base polymeric binder. Published in Journal of the American Ceramic Society, Vol. 84, No. 2,

3 COMPARATIVE STUDY OF MICROSTRUCTURE AND PROPERTIES OF ZIEGLER-NATTA AND METALLOCENE BASED POLYETHYLENES IN INJECTION MOLDING ย พาพร ร กสก ลพ ว ฒน สาขาว ชาว ศวกรรมพอล เมอร ส าน กว ชาว ศวกรรมศาสตร มหาว ทยาล ยเทคโนโลย ส รนาร Comparisons between injection moldings of linear low density polyethylenes (LLDPE s) polymerized using metallocene and Ziegler-Natta catalysts were made. One grade of based metallocene base LLDPE s has similar melt flow index (MFI) as Ziegler-Natta based LLDPE. Injection molding runs were performed at various processing conditions such as injection speed, melt temperature and holding pressure. Microstructure and mechanical property were measured including the gapwise distribution of spherulite size, degree of crystallinity, shear-induced crystallization layers, and tensile properties. The effects of processing conditions on these values were determined. Published in the Proceedings of the 59 th Annual Technical Conference (ANTEC), Society of Plastics Engineers (SPE), Dallas, Texas, U.S.A., May 6-10,

4 ON-LINE MONITORING OF FREE RADICAL GRAFTING IN A MODEL TWIN SCREW EXTRUDER Kasama Jarukumjorn and Kyonsuku Min Institute of Polymer Engineering, University of Akron, Akron, OH, U.S.A. The on-line monitoring system of Raman spectroscopy was developed to monitor the grafting identification and level of grafting of glycidyl methacrylate (GMA) onto low-density polyethylene (LDPE). The reactive extrusion and melting behavior of GMA and LDPE were monitored by a fiber optic probe through the glass windows mounted on the model non-intermeshing counter rotating twin screw extruder. Monitoring concentration of GMA along the screw extruder was carried out to determine the reaction level. Published in SPE ANTEC, 2064,

5 ON-LINE RAMAN SPECTROSCOPY FOR MONITORING OF FREE RADICAL GRAFTING IN A MODEL TWIN SCREW EXTRUDER Kasama Jarukumjorn School of Polymer Engineering, Suranaree University of Technology Kyonsuku Min Institute of Polymer Engineering, University of Akron, Akron, OH, U.S.A. A fiber optic Raman spectroscopy is developed to monitor the grafting of GMA onto LDPE in a model non-intermeshing counter rotating twin screw extruder which has a series of glass windows along the extruder. The fiber optic probe is mounted on the glass windows of the extruder. The melting behavior and GMA concentrations are followed along the extruder. The reaction takes place at the second chamber of the extruder as indicated by the reduction of monomer concentration and LDPE melting behavior. Published in the Proceeding of the 1 st Thailand Materials Science and Technology Conference, Bangkok,

6 POLYMER ASSISTED LAMINATION OF CERAMIC GREEN TAPE Nitinat Suppakarn School of Polymer Engineering, Suranaree University of Technology Zhien Liu and James D. Cawley Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, OH, USA Multilayer manufacturing processes allow easy fabrication of large or, more often, complex ceramic components. Commonly in this process, a sheet-like powder-compact or green tape is first prepared. Then, the sheet materials are cut or punched into the desired shapes before joining together and sintering to obtain the final ceramic component with useful properties. Solvent lamination for alumina green tapes has been readily accomplished using a mixture of ethanol, toluene and poly(propylene glycol), PPG. However, the role of nonvolatile component, PPG, during the lamination process was not clearly understood. The purpose of the work reported herein is to determine the redistribution of the PPG during subsequent processing of green tape lamination. Based on these results, the environmentally friendly, solvent free system, for green tape lamination was developed. Published in the 1st Thailand Materials Science and Technology Proceedings, MTEC, Bangkok,

7 COATED FEEDSTOCK FOR FABRICATION OF CERAMIC PARTS BY CAM-LEM Zhien Liu Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, Ohio, U.S.A. N. Suppakarn and James D. Cawley Department of Macromolecular Science, Case Western Reserve University, Cleveland, Ohio, U.S.A. In laminated object manufacturing of ceramic components, lamination is one of the most important materials issues. Good lamination can ensure monolithic finished component. Otherwise, lamination defect will occur in the parts, which will affect the properties of ceramic components. Adhesive (both liquid and non-liquid) lamination were developed for the cut-then-stack (CAM-LEM) procedure. Especially, the non-liquid adhesive lamination was discussed in more details. Published in the Proceedings of the Solid Freeform Fabrication Symposium Proceedings, University of Texas, Austin, TX, U.S.A.,

8 INTERFACIAL BEHAVIOR OF EPOXY/E-GLASS FIBER COMPOSITES UNDER WET-DRY CYCLES BY FOURIER TRANSFORM INFRARED MICRO SPECTROSCOPY Wimonlak Noobut and Jack. L. Koenig The interfacial behavior of epoxy/glass fiber micro-composites under cycles of wet and dry environment change was investigated by Fourier Transform Infrared (FTIR) microspectroscopy. The adsorbed water content in the epoxy/fiber interphase under moist conditions is reduced by treating the glass fibers with a silane-coupling agent, γ-aminopropyltriethoxysilane. This results in a significant decrease in the ringopening polymerization of epoxy in the epoxy/fiber interphase. It is also found that the wet-dry cycles cause significant variation of the residual adsorbed water in the interphase regions. There is an indication that the debonding in the epoxy/silane-treated fiber interphase is slower than the epoxy/heat-cleaned fiber interphase. Published in Polymer Composites, Vol. 20,

9 MOLECULAR CHARACTERS OF SHARKSKIN PHENOMENON IN METALLOCENE LINEAR LOW DENSITY POLYETHYLENES C. Deeprasertkul and S.Q. Wang Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH, U.S.A. C. Rosenblatt Department of Physics, Case Western Reserve University, Cleveland, OH, U.S.A. The effect of molecular weight on sharkskin dynamics is systematically studied using three metallocene-catalyzed linear low density polyetheylenes (mlldpe) of different molecular weights. A new experimental method is developed to enable in-situ characterization of the time scale τ on which the sharkskin forms the extrudate. This laser scattering technique directly measures the periodic variation of the scattered light off the rough sharkskin-like extrudate surface. It is found that τ increases with molecular weight as strongly as the overall molecular chain relaxation time τ *, determined from oscillatory shear measurements. The observed molecular weight dependence provides additional support for the recently proposed interfacial stress growth/relaxation mechanism for sharkskin formation. Published in Macromolecular Chemistry and Physics,

10 THE INFLUENCE OF INTERFACIAL AGENTS ON THE IMPACT STRENGTH OF POLY (VINYL CHLORIDE) AND SOFT FILLER COMPOSITES F.H. Axtell, K. Jarukumjorn, and W. Sophanowong Department of Chemistry, Faculty of Science, Mahidol University The impact strength of rigid poly (vinyl chloride) (PVC) filled with scrap dust obtained from the buffing process in sports shoe sole manufacture has been investigated. Dust from outsoles and midsoles which had been treated with silane and zirconate coupling agents were mixed into PVC at various levels of coupling agent addition. The effects of polymeric interfacial agents (compatibilisers) were studied for 15 different agents by preparing them as masterbatches with the soft fillers, then mixing them into the PVC at various levels of filler loading and compatibiliser level. The zirconate coupling agent performed better than the achieved by using compatibilisers. Three good compatibilisers were identified for midsole filled PVC and one for outsole filled PVC. The impact strength was dependent on the compatibiliser type and level, and on the filler type and loading. The good compatibilisers improved the dispersion level of the soft fillers in the PVC and gave high impact strength with no reduction in heat distortion temperature and only a slight drop in hardness. The tensile properties changed to give lower ultimate stress and higher elongation at break. The results show that the addition of 2% of a good compatibiliser can double the Charpy notched impact strength of soft filled PVC, and give super or performance at lower cost than a 5% loading of a commercial ABS impact modifier. Published in Plastics, Rubber, and Composites Processing and Application, Vol. 22, No. 2,

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