Effects of Various Nanofillers and Sc-Carbon Dioxide Forming Conditions on the Structure and Properties of Poly(Lactic Acid) Blend-Based Nanocomposites and Foams

Biopolymers have attracted much attention during the past decades due to their eco-friendly characteristic. However, the disadvantages including narrow processing window, low heat resistance, and low strength, limit their applications. To improve the properties of biopolymers, the development of so-called “bionanocomposites” is one of the feasible ways. If the bionanocomposite foams could be further achieved through supercritical CO2 foaming process, the versatility of biopolymers can be extended. Poly(lactic acid) (PLA), possessing biomass/biodegradable character, is one of the most used biopolymers and shows great potential in replacing commodity polymers for certain applications. Poly(butylene adipate-co-terephthalate) (PBAT) is an emerging biodegradable polymer. It could serve as a blend counterpart for improving the toughness of PLA. Polycarbonate (PC) is an important engineering polymer, and was successfully blended with PLA to enhance the heat resistance of PLA, as reported. According to the literature, the blend-based bionanocomposites are expected to achieve better performance compared with the neat components and blends. In this 3-year project, the PLA/PBAT and PLA/PC blend-based nanocomposites and their foams will be prepared through melt-mixing and scCO2 foaming procedures under various conditions. The studies on the relation between phase morphology/(cell)structure and properties of prepared nanocomposites/foams will be highlighted. In the first year, PLA/PBAT/nanoCB and PLA/PBAT/CNT (with compatibilizer) ternary nanocomposites/foams with different nanocarbon loadings will be investigated. The different nanofillers will be added to the polymer matrix sequentially or simultaneously upon the mixing processes. In the second year, PC will replace PBAT to prepare the ternary PLA/PC blend-based nanocomposites/foams (with compatibilizer) for characterizations. Special attentions will pay to the selective localization of nanofillers and the mechanism of (double) percolation/nanocell formation. In the third year, GNP of different dimensions will be utilized to prepare the PLA blend-based nanocomposites and foams under various conditions. The effects of foaming condition, nanofillers’ addition and blend composition on the structure and properties of resultant blends/nanocomposites/foams will be investigated in each year. The instruments/equipments that will be employed for this project include: internal mixer/twin screw extruder, FESEM, TEM, DSC, TGA, PLM, WAXD, FTIR, DMA, rheometer, density/resistivity/dielectric meters etc.* nanoCB: nano carbon black; CNT: multi-walled carbon nanotube; GNP: graphene nanoplatelet

Project ID:PB10907-2463
External Project ID:MOST109-2221-E182-057-MY3