The aim of this work is to study the effects of different simulated mechanical recycling processes on the structure and properties of PLA. A commercial grade of PLA was melt compounded and compression molded, then subjected to two different recycling processes. The first recycling process consisted of an accelerated ageing and a second melt processing step, while the other recycling process included an accelerated ageing, a demanding washing process and a second melt processing step. The intrinsic viscosity measurements indicate that both recycling processes produce a degradation in PLA, which is more pronounced in the sample subjected to the washing process. DSC results suggest an increase in the mobility of the polymer chains in the recycled materials; however the degree of crystallinity of PLA seems unchanged. The optical, mechanical and gas barrier properties of PLA do not seem to be largely affected by the degradation suffered during the different recycling processes. These results suggest that, despite the degradation of PLA, the impact of the different simulated mechanical recycling processes on the final properties is limited. Thus, the potential use of recycled PLA in packaging applications is not jeopardized.

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ABSTRACT:In this research a study was conducted with the aim of gaining insight into the effect exerted by poly( epichlorhydrin) (PECH) on the compatibility and microstructure of the blend consisting ofpoly(ethylene oxide) (PEO) and a polyphosphazene (PPz). For the different PEO/PPz systems and varying amounts of PECH isothermal crystallization was analyzed, as well as non-isothermal crystallization, spherulite growth geometry, and the Flory-Huggins interaction parameter. The results obtained point towards a partially compatibilizing effect of PECH on PEO/PPz. KEY WORDS Poly(ethylene oxide) / Polyphosphazene / Poly(epichlorohydrin) / Crystallization / Glass Transition Temperature / Spherulite Growth Rate / Compatibility / According to our findings in previous work, 1 the blend between poly(ethylene oxide) (PEO) and poly( octafluoropentoxytrifluoroethoxy) phosphazene (PPz) proved to be incompatible over the whole range of compositions. In pursuance of our interest in the synthesis of polymeric electrolytes resulting from solvating the polymeric blend with lithium salts, one of the objective set for this research was to attempt a compatibilization of this polymer blend by means of incorporating another polymer which would act as a compatibilizer, with the effect that ion transfer through the resulting blend would no longer be hindered .or interfered with by the presence of interphases.In this sense poly(epichlorohydrin) (PECH) was chosen as a compatibilizing polymer to combine with the different compositions of the binary system PEO/PPz. The main interest of our work focused on gaining insight into the microstructure and compatibility of the system PEO/PPz. In the course of this study the crystallization kinetics was analyzed, glass transition temperature was measured, spherulite 786 growth kinetics was recorded and the FloryHuggins interaction parameter was determined via PEO melting point depression. EXPERIMENT ALThe following commercial polymers were used: Poly(ethylene oxide) (PEO) (Mw= 5.0 x 10 6 ) was supplied by Aldrich; the poly(octafluoropen toxytrifluoroethoxy) phosphazene (PPz) PNF-200 was obtained from Firestone and the poly(epichlorohydrin) (PECH) (Mw= 7.0 x 10 5 ) from Aldrich.The blends were obtained by dissolving in acetonitrile and chloroform the already proportioned polymers, subsequently vaporizing the solvent and drying the samples under high vacuum conditions until constant sample weight was achieved.Isothermal crystallization and melting were measured in a Perkin Elmer differential scanning calorimeter DSC 7. The samples were heated to I00°C, where they were held for five minutes in order to delete their thermal

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