Melt-solid Polycondensation of Butyl Lactate from Kitchen Waste to Obtain Polylactic Acid

Butyl lactate,extracted and purified from the fermentation broth of kitchen waste,was studied to successfully obtain high-molecular-weight polylactic acid(PLA),catalyzed by a SnCl2/TSA binary system.At first,a solid condensate was prepared by melt polycondensation of butyl lactate at 160℃ for 10h,and then it was subjected to solid-state polycondensation at 140℃ for 40h to increase the molecular weight,which produce PLA with an Mη of 22,000.The results from IR and XRD spectrums showed that the product was poly(D,L-lactic acid)(PDLLA).This process by omitting butyl lactate hydrolysis can afford a new route to simplify synthesis of PLA,avoid the corrosion of equipment,and decrease PLA production cost from kitchen waste.