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An Investigation into Effects of Components Ratio and Nano/micro Sized ZnO Particles on Evolution of Transesterification Reaction, Compatiblization and Modification of PET/PC Blends Structure

Ghahramanzadeh Asl, Hadi | 2015

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48569 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Bagheri, Reza; Pircheraghi, Gholamreza
  7. Abstract:
  8. Polycarbonate (PC) and polyethylene-terephthalate (PET) are important engineering thermoplastics. During last decades these polymers and their blends have been studied extensively due to their wide range of applications. Blends of PET and PC combine mechanical properties and chemical resistance together, which make applicable in various components such as automotive, electrical and of medical parts. It has been accepted that PET/PC immiscible blends are subjected to transesterification reactions during thermal processing, which produces PET-PC copolymer chains. In fact, scissioning and substitution of ester/carbonate functional groups of PC and PET at the interface, transforms the initial homopolymer to block copolymer. Evolution of transesterification reactions and production of Interfacial copolymers can noticeably affect miscibility, phase morphology and consequently the final properties of blends by compatibilizing PET and PC immiscible blends. In the first section of current study, structures and comprehensive properties of PET/PC reactive melt blends are investigated, regarding outstanding role of exchange reaction products. The systematic study on PET/PC blends study seemed to be crucial since most of the researchers focused their study on a specific area. This route provide a deeper insight into compatibilization phenomena. All of the results demonstrated that intermediate compositions are more probable to interact. Interfacially produced co-polymers were taken into account to reliably interpret compatibilization and miscibility improvement observed at these samples. This study, also provide a quantitative rheological analysis on the framework of the Palierne model and address interfacial tension as a key factor explaining the interaction of PET and PC phases. Since few studies have been dealt with rheological properties of PET/PC blends, calculation of interfacial tension, connect structural features to the rheological/interfacial properties and also bring an advantage form novelty standpoint. There is reduction up to 45.7% in the value of interfacial tension in sample containing 60% PET, originally related to copmpatibilizing copolymers at the interface. In the second section catalyc activity of nano and micro sized ZnO particles on transesterification reaction were investigated. 1H-NMR and FT-IR results indicated that formation of PET-PC copolymer chains was catalysed in presence of ZnO particles. Mechanical and thermal properties revealed that positive role of ZnO particles on progress of transesterification reactions can suppressed due to negative effect of destructive reactions at hight ZnO containing samples. Thus the optimum ZnO content found to be around 1 and 2 wt% for nano and micro sized ZnO particles, respectively. Based on the results of current study, nano sized ZnO particles are more effective in compatibilization of PET/PC immiscible blends through promoted interfacial copolymer formation and absence of destructive reactions
  9. Keywords:
  10. Polyethylene Terephthalate ; Interfacial Tension ; Zinc Oxide Nanoparticles ; Viscoelastic Properties ; Ester Exchange Reaction ; In-Situ Copolymerization ; Palierne Model

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