METHOD FOR PREPARING POLYLACTIC ACID AND PRODUCTS THEREOF USING A TWIN-SCREW EXTRUDER

摘要

A method for preparing polylactic acid and products thereof using a twin-screw extruder, in which a carbene carbon dioxide adduct of formula (I) is mixed with lactide, and then reactive extruded through a twin-screw extruder to produce polylactic acid and products thereof. In formula (I), the dotted line represents optional double bond; X1 is selected from S or N; X2 is selected from C or N; R1, R2 are selected from the same or different groups of hydrogen, alkyl with 1~10 carbon atoms, alkyl with 1~10 carbon atoms and substituted by one or more of halogen atom, hydroxyl group, phenyl and cyano group, cycloalkyl with 3~6 carbon atoms, halogen atom, adamantyl, phenyl and phenyl substituted by one or more of halogen atom, hydroxyl group, alkyl and cyano group; R3, R4 are selected from the same or different groups of hydrogen, halogen atom, cyano group, hydroxyl group, alkyl with 1~4 carbon atoms, alkyl with 1~4 carbon atoms and substituted by one or more of halogen atom, hydroxyl group, phenyl and cyano group, phenyl and phenyl substituted by one or more of halogen group, hydroxyl group, alkyl and cyano group; or R3 and R4 are connected to form a ring with 3~8 carbon atoms; or R2 and R3 are connected to form a five- or six-membered N-containing heterocycle which is unsubstituted.