Tailoring flexibility and dispersity of thermoplastic starch gel by controlling intermolecular structure for improving folding endurance of polylactide

Abstract Polysaccharide-based gels are green, non-toxic, and sustainable materials with a high absorption capability, which make them suitable for numerous applications. In this study, a novel starch-based thermoplastic gel (TGTPS gel) was facilely fabricated via reactive extrusion with glycerol, starch and tartaric acid. The TGTPS gels exhibited tremendous increase of flexibility and processability, which was attributed to the fact that TA molecules could facilitate hydrolysis of starch chains and enhance gel network slippage as evident from gel permeation chromatography and stress-relaxation measurement. Moreover, combining dynamic mechanical analysis and rheological behavior, we found that a special Soft-Hard Segments structure, varied with the fluctuation of tartaric acid (TA) concentration, was developed between TA molecules, glycerol and starch chains. Additionally, TGTPS gels with 1% TA content (TGTPS-1) could also serve as micro/nano-meter toughener, and motivate PLA to achieve outstanding folding endurance. The double folding resistance was performed on PLA/TGTPS-1 blend, and folding cycle time was improved from 1 time of PLA to over 2000 times of PLA/TGTPS-1 (80/20) blends. Overall, this novel TGTPS gels could be promising alternative to petroleum-based polymers and play a great potential in engineering applications.