Abstract: Ploy(lactic acid) (PLA) was chain-extended by an epoxy chain extender (ADR4370F) through melt extrusion, and then its rheological behavior and mechanical properties were investigated. The rheological evaluation indicated that the storage modulus, loss modulus, complex viscosity, relaxation time, and relaxation modulus of PLA were improved due to the chain extension by ADR4370F. Moreover, the elastic response became faster with the addition of ADR4370F but viscous dissipation became weaker. PLA exhibited a gel-like behavior when 1.0 wt % of ADR4370F was incorporated. Cole-Cole plots exhibited a branched structure formed by chain extension, and meanwhile vGP plots further predicted a star-like topological structure within the chain-extended PLA. The mechanical tests showed that the notched impact strength of PLA were improved with the addition of ADR4370F, and however there was almost little effect on tensile strength. With the addition of 1.0 wt % ADR4370F, the notched impact strength of PLA was improved to 6.0 kJ/m2, presenting an increase by 65.75 % compared with that of pristine PLA.

Key words: poly(lactic acid), epoxy chain extender, rheological behavior, mechanical property