Sustainable chemical recycling of poly(L-lactic acid) using montmorillonite

In order to establish the sustainable chemical recycling process of poly(L-lactic acid), a high molecular weight poly(L-lactic acid) was transformed into the corresponding lactate oligomers having a molecular weight of few hundreds by using environmentally benign solid acids, such as montmorillonite K10. The oligomer was repolymerized by the conventional chemical catalysts forming a high molecular weight poly(L-lactic acid). It was also confirmed that the repolymerized product showed the same T_m as that obtained by the polymerization of the authentic L-lactic acid. This chemical recycling process was applicable to poly[(L-lactic acid)/( ε -caprolactone)] copolymer.