초록
This study aims to investigate a ''green'' recycling route for polybutylene succinate (PBS) based on reactive extrusion in the presence of an enzyme catalyzing the hydrolysis of this aliphatic polyester: lipase B from Candida antarctica. This enzyme was chosen due to its thermal stability, since reactive extrusion was performed at 120<SUP>o</SUP>C (i.e. above PBS melting temperature). PBS hydrolysis was measured after extrusion at 120<SUP>o</SUP>C either in a single or a twin screw extruder, in the presence of 0-10wt% C. antarctica lipase for 5 or 30min. In a twin screw extruder, the residual activity of the enzyme was still 38% or 24%, after 5-30min extrusion at 120<SUP>o</SUP>C, respectively. For instance, the weight average molecular weight (M<SUB>w</SUB>) of PBS decreased from 82,000 to 4500gmol<SUP>-1</SUP> after extrusion for 5min in the presence of 1% wt of lipase. The highest yield of free succinic acid release (44%) was obtained following a 30min extrusion in the presence of 10wt% of C. antarctica lipase. The drastic decrease in weight average molecular weight of PBS after enzymatic hydrolysis caused an only 10<SUP>o</SUP>C decrease in the melting temperature.