High efficient recovery of L-lactide with lignin-based filler by thermal degradation.

• LG- g -PDLA can simultaneously improving the original properties and recovery efficiency of PLLA. • A small amount of PDLA in LG- g -PDLA did not lead to an increase of D-LA production of PLLA. • More L-LA and less D- and meso -LA were recovered from PLLA/LG- g -PDLA at 240 °C. • The thermal degradation of PLLA/LG- g -PDLA was put forward as less random and more unzipping depolymerization.. The biorefinery and high-value utilization are the development tendency in the study of lignin. Lignin- graft -poly(D-lactic acid) (LG- g -PDLA) is a new kind of poly(L-lactide) (PLLA) filler. In order to clarify the effects of LG- g -PDLA on PLLA pyrolysis, PLLA/LG- g -PDLA (1 wt% filler) and pure PLLA were prepared and subjected to reveal the degradation mechanisms with proton and carbon-13 nuclear magnetic resonance spectrometer (H- and 13C-NMR) and gel permeation chromatography (GPC). More L-LA and less D- and meso -lactide (D- and meso -LA) were recovered from PLLA/LG- g -PDLA at 240 °C. By analyzing the NMR and GPC data, the thermal degradation of PLLA/LG- g -PDLA was put forward as being possible mechanisms of less random and more unzipping depolymerization. The results of lactides yields at different conditions better guide the optimization of PLLA recovery. Moreover, this innovative blending approach can simultaneously achieve high-value utilization of lignin and recovery efficiency of PLLA. [ABSTRACT FROM AUTHOR]