PLA degradation pathway obtained from direct polycondensation of 2-hydroxypropanoic acid using different chain extenders

摘要: This work is focused on the structural, thermal and mechanical studies of direct polycondensation poly (lactic acid) (PLA) modified with three different chain extenders (1,3-phenylene-bis-2-oxazoline, PBO; pyromellitic dianhydride, PMDA; 1,1′-carbonyl bis caprolactam, CBC). Three concentrations PBO, PMDA CBC (0.2, 0.5 1 wt%) were added during stages (S): monomer dehydration (80 °C, S1), oligomer (130 S2) melt (160 S3). FTIR, Raman 1H-NMR spectroscopies revealed presence signals produced by interactions between OH C=O end groups PLA reactive functional extenders. It was found that interaction extender decreased crystallinity. Furthermore, data from analysis increased mobility, which represented a decrease in its Tg. Enhanced properties, hardness, elastic modulus indentation creep observed addition extenders, improving performance wt% PBO at S3, either S2 or S3 0.25 S3. Additionally to synthesis, degradation mainly influenced more than any specific stage addition. Finally, structural characterizations PLA-PBO, PLA-PMDA PLA-CBC systems resistant UV light humidity accelerated weathering test.