Thermally stable polylactides by stereocomplex formation and conjugation of both terminals with bio-based cinnamic acid derivatives
Novel polylactides (PLAs) with conjugation of both terminals by cinnamic acid (CA) derivatives showed high thermal stability and photoreactivity. Their stereocomplex formation was influenced by the conjugation groups at both chain ends of the PLAs and showed photoreactivity and a dramatic improvement in their 10% weight thermal decomposition temperature (T10) from 250 to 320 or 345 °C for conjugated CA or 3,4-diacetoxycinnamic acid (DACA). Interestingly, CA or DACA-conjugated stereocomplexes showed above 98% weight remaining, although the original PLAs showed a 23 wt% pyrolysis, during isothermal degradation at 200 °C for 120 min. The thermal stability and photoreactivity of the PLAs or their stereocomplexes were controlled by the cinnamic acid derivatives. These PLAs and their stereocomplexes may be useful as functional bio-based materials for various application fields.