Effect of Blending Procedure on Tensile and Degradation Properties of Toughened Biodegradable Poly(lactic acid) Blend with Poly(trimethylene terephthalate) and Reactive Compatibilizer. Issue 11 (18th September 2019) - Kultravut, Katanyu
Abstract: This research focuses on brittleness improvement of biodegradable poly(lactic acid) (PLA) by reactive melt blending with poly(trimethylene terephthalate) (PTT). First, PLA is simultaneously blended with PTT and a reactive compatibilizer, poly(ethylene‐ co ‐glycidyl methacrylate) (PEGMA), (one‐step blending procedure). In the PLA/PTT/PEGMA blend, PEGMA mainly disperses in the PLA matrix phase, and the blend shows unimproved tensile properties. To increase the reaction between PTT and PEGMA, PEGMA is sequentially blended with PTT then PLA (two‐step blending procedure). This procedure is effective in drastically enhancing elongation at break of the blend. The strain at break of the blend formed by two‐step blending is significantly improved because the blending procedure affects the blend morphology. PLA‐ g ‐PEGMA‐ g ‐PTT graft copolymer is formed at the interface between PLA and PTT during reactive melt blending with PEGMA when the two‐step blending procedure is employed as a blending method which is confirmed by Fourier transform infrared spectroscopy and viscosity measurement. Such features bring about craze formation during tensile test and this is the reason why the toughening is achieved by the two‐step blending procedure. Abstract : A super‐tough poly(lactic acid) blend is successfully prepared by blending with poly(trimethylene terephthalate) and a reactive compatibilizer through a two‐step blending procedure. A significant increase in elongation at break is observed. This improvement is believed to be due to craze formation in the elongated area as a toughening mechanism. Moreover, the thermal and degradation stability are enhanced.