Glycidyl methacrylate functionalized star-shaped polylactide for electron beam modification of polylactic acid: Synthesis, irradiation effects and microwave-resistant studies

ABSTRACT A model of acrylate functionalized polyfunctional star-shaped polylactic acid (star-PLLA) was originally proposed for free radical-induced modification of PLA under electron beams (EB) irradiation. The 4-arms star-PLLA was synthesized by ring-opening polymerization and it was further functionalized with glycidyl methacrylate (GMA). The PLA films containing the star-PLLA-GMA additive were EB-irradiated with the absorbed doses of 10-100 kGy. Effects of the star-PLLA-GMA contents and the absorbed doses on the morphologies, pseudo-gel fraction, swelling degree, chemical structure, molecular weight, G-value, thermal stability, crystallinity, and mechanical properties were demonstrated. The star-PLLA-GMA reduced radiation-induced chain scission of PLA under EB irradiation as known from the G-value of chain scission (Gs) and pseudo-gel fraction. The PLA properties, i.e., crystallization, thermal and mechanical characteristics, were improved by the addition of the star-PLLA-GMA and EB irradiation process. The EB-irradiated star-PLLA-GMA/PLA also exhibited an evidence of microwave-resistant property. The reactive multi-branched star-PLLA-GMA and EB irradiation is one of the promising models for PLA modification towards the development of microwavable bioplastics for food packaging.