Study On Preparation And Property Control Of PBAT Composites

Biodegradable polymers,particularly polybutylene terephthalate(PBAT),are of increasing interest due to the significant environmental safety risks posed by non-biodegradable plastic waste.However,high production costs and low thermal and mechanical properties limit the use of PBAT,which is advantageous only when biodegradability is required.PBAT is usually blended with polylactic acid(PLA)or selectively added with natural fillers to prepare PBAT-based composites to obtain improved properties.However,the incompatibility of PBAT with PLA and the dispersion of fillers in PBAT need to be addressed.To address the above problems,a series of PBAT-based composites were prepared using epoxidized soybean oil(ESO)with PLA,methyl methacrylate-glycidyl methacrylate copolymer(MMA-GMA,referred to as MG)with PLA,and long-chain ionic liquid1-hexadecyl-3-methylimidazolium chloride salt(IL)with sodium-based montmorillonite(Na+MMT)as fillers,respectively.The improvement of the comprehensive performance of PBAT-based composites was discussed in depth.The main contents are as follows:(1)PLA-reinforced PBAT-based composites were used,and ESO was used as an reactivity compatibilizer agent to reactively bulk the PBAT/PLA blends.The reaction mechanism is that the epoxy group on ESO can react with the terminal carboxyl and hydroxyl groups of PBAT and PLA,which in turn generates PBAT-g-ESO-g-PLA branched macromolecules and improves the compatibility of PBAT and PLA by enhancing the interfacial interactions.Meanwhile,ESO acts as a bio-based additive to ensure the fully biodegradable properties of the composites.Infrared spectroscopy confirmed the capacitance-enhancing mechanism of ESO,indicating that ESO was able to react with PBAT and PLA to form a chemically bonded interface.The improved compatibility resulted in the close glass transition temperature of the two phases,while the processing and tensile properties were significantly improved.the maximum fracture strain of the PBAT/PLA/ESO blend was 792%and the tensile strength was 35.7 MPa at 6 wt%of ESO addition,which was 2.1 and 3.1 times higher than those of the PBAT/PLA composites,respectively.(2)To further improve the mechanical properties of PBAT-based composites,a homemade MMA-GMA copolymer was selected as a compatibilizer to improve the compatibility of PBAT and PLA.Based on the same capacitating mechanism,the formation of branched macromolecules improved the compatibility between them,and the better miscibility of PLA and MG inhibited the cold crystallization and melting behavior of PLA.The capacitating effect promotes the particle size of the PLA phase to be smaller and uniformly dispersed.Meanwhile,the non-homogeneous nucleation effect of PLA was enhanced,leading to a higher crystallization temperature of PBAT.higher complex viscosity and modulus of PBAT/PLA/MG blends demonstrated improved interfacial interactions and melt strength,and better ductility and stiffness balance were achieved.At6 wt%MG addition,the PBAT/PLA/MG blend achieved 694%maximum strain and 49MPa tensile strength,which were 1.8 and 4.3 times higher than those of PBAT/PLA composites,respectively.(3)In order to obtain more outstanding properties of PBAT-based composites,IL was used to reinforce PBAT in concert with Na~+MMT.A series of PBAT/MMT/IL nanocomposites were prepared by blending PBAT,Na~+MMT and IL in a one-step melt blending process.By ion-exchange reaction,IL exfoliated Na~+MMT in the PBAT matrix and improved the agglomeration effect of Na~+MMT.the XRD and SEM results demonstrated that Na~+MMT in the ternary blends could be completely exfoliated by IL.The well-dispersed Na~+MMT improved the modulus and melt strength of the blends,while enhancing the crystallization behavior of PBAT.In addition,the presence of IL endows the composites with excellent dielectric properties and antibacterial ability,which provides new ideas for the application of PBAT-based composites.