Reactive compatibilized PLA/modified EVA blends for injection products

Abstract

Transesterification of ethylene(vinyl acetate) or EVA via catalytic reactive extrusion in the presence of 1-dodecanal and dibutyl tin dilaurate (DBTL) catalyst was completely occurred in a twin-screw extruder at a screw speed of 10 rpm in order to alter the vinyl acetate groups in the chains to be hydroxyI groups. The result from FTIR and dynamic mechanical test revealed that the increment of hydroxyl groups to EVA chains was successfully obtained via catalytic reactive extrusion. The synthesis of modified EVA (mEVA) via the effective methods as mentioned earlier was blended with PLA and four different type of compatibilizers; i.e. Ethylene-glycidyl methacrylate copolymer (E-GMA), ethylene-methyl acrylate-glycidyl methacrylate terpolymer (T-GMA), Ethylene-acrylic acid copolymer (PE-AA), and Poly(2-ethyl-2-oxazoline) (Oxa) at various amounts of mEVA (10, 20, 30, and 40 wt%) and at 5, 10 and 15 phr of compatibilizers loading. The PLA/mEVA/compatibilizers blends were prepared in a co-rotating twin-screw extruder with a screw speed of 30 rpm. Morphological interpretation through FE-SEM revealed the separation between PLA and mEVA phases in the presence of mEVA. On the other hand, FE-SEM images presented the improvement in compatibility of the PLA/mEVA blends in the presence of compatibilizers.