Preparation And Properties Of PLA Composites

PLA blended with poly (butylene adipate-co-terephthatate)(PBAT) by melt extrusionwas studied in this paper. Different molecular weight polyglycol were used as compatilizers inthis system. On this basis, several inorganic fillers such as Filler A, SiO2, wollastonite, Mica,CaCO3were used as reinforce agent in PLA/PBAT(80/20) system to prepare three-elementcomposites. Properties of mechanical, thermal and crystallization were investigated. Themajor results are summarized as following:(1)SEM graphs and DMA figures showed that PLA and PBAT are incompatible system,notched impact strength and elongation of composites were significantly improved with theincorporation of PBAT, at the same time stress strength and heat deflection temperature weredecreased. Crystallization rate of PLA was very low as to the result of POM, and PBAT canaccelerate the crystallization rate of PLA/PBAT(80/20) system under the investigation ofPOM. XRD patterns showed that incorporation of PBAT did not change the crystal form ofPLA.(2)PEG significantly improved the compatibility of PLA and PBAT, and also increasedthe toughness of composites, wherein4000molecular weight of PEG worked better than400.POM graphs and XRD patterns showed that PEG accelerated the crystallization rate ofpolymer and make the size of spherulites larger.(3)Mechanical properties and HDT of three-element composites were improved with theincorporation of inorganic fillers, however the results and trend were quite different.Composites with15%8000mesh Filler A or5%precipitated silica got an significantimprovement of both the mechanical and heat properties while other fillers made smallerperformance improved. The most important is other fillers could not improve all theseproperties at the same time. XRD patterns showed that8000mesh Filler A and precipitatedsilica also improved the degree of crystallinity of the composites while other fillers had littleinfluence on the crystallization of composites. POM graphs showed that8000mesh Filler Awas a good nucleating agent of PLA, it can promote heterogeneous nucleation of PLA and significantly improved the nucleation density and degree of crystallinity, but precipitatedsilica had no effect on the crystalline property of composites.