The Critical Role of Processing Sequence on the Mechanical Properties of Reactively Compatibilized PLA/PBAT Blends: Effect of Manufacturing Method
Sanaz Soleymani Eil Bakhtiari, Reza Salehiyan, Anu Sasi, Islam Shyha, Dongyang Sun
Abstract
Abstract In this study, polylactic acid (PLA)/polybutylene adipate‐co‐terephthalate (PBAT)/Joncryl blends are prepared via film extrusion, compression molding, and injection molding to investigate the effects of processing sequence and compatibilization on interfacial interactions and final properties. Joncryl is added at 0.5 and 1 wt.% to assess its impact on phase adhesion, crystallinity, and mechanical performance. Results reveal that the two‐step blending process, where Joncryl is first reacted with either PLA or PBAT, results in more uniform dispersion and enhanced interfacial interactions compared to the single‐step method. Notably, the (70/30) PLA/PBAT blend incorporating 1 wt.% Joncryl via two‐step blending shows tensile strength improvements of ≈6% and 15%, and elongation increases of ≈491% and 335.5% for (PLA+1J)/PBAT and (PBAT+1J)/PLA, respectively. For injection‐molded samples, 0.5 wt.% Joncryl added through two‐step blending improves elongation and impact strength by ≈75% and 140% in (PBAT+0.5J)/PLA. Film‐extruded samples exhibit higher tensile strength than compression‐molded ones due to better phase dispersion, orientation, and interfacial bonding enabled by slit‐die extrusion and stretching. In contrast, compression molding lacks orientation effects, resulting in lower mechanical strength. These findings highlight the critical role of blending sequence and processing method in tailoring biodegradable PLA/PBAT blends for improved performance in packaging and related applications.