Preparing polyhydroxycarboxylic acid filled with vegetable flour, useful as biodegradable material, comprises polycondensation of hydroxycarboxylic acid followed by reaction with expansion agent in the presence of vegetable flour

摘要

#CMT# #/CMT# Preparing a polyhydroxycarboxylic acid filled with vegetable flour, comprises: polycondensation of a hydroxycarboxylic acid to form a functionalized prepolymer; and reaction of the functionalized prepolymer with an expansion agent in the presence of vegetable flour to form a polyhydroxycarboxylic acid of heavy mass. #CMT# : #/CMT# An independent claim is included for polyhydroxycarboxylic acid having an average molecular mass of 1000-120000 g/mol, a polydispersity index of 1.2-2.5, acid index of 0-30 mgKOH/g, glass transition temperature of 35-50[deg]C and a vegetable flour content of 1-50 wt.%. #CMT#USE : #/CMT# The polyhydroxycarboxylic acid is useful as fully biodegradable material in a renewable carbon based natural medium (claimed). #CMT#ADVANTAGE : #/CMT# The polyhydroxycarboxylic acid is completely biodegradable in a renewable carbon based natural medium (claimed) without any need for microorganisms. The polyhydroxycarboxylic acid is harmless to the environment. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Process: The polycondensation is carried out by direct dehydration in the presence of a diol or diacid compound e.g. succinic acid, adipic acid or 1,4-butanediol. The polycondensation is carried out in the presence of catalysts such as metals of group I, II, III and/or IV, or their salts. Preferred Components: The expansion agent is oxazoline, caprolactam or isocyanate, preferably 2,2-bis(2-oxazoline), 1,3-phenylene-bis (2-oxazoline), carbonylbiscaprolactam or 1,4-butanediisocyanate. The vegetable flour is amylose cereal flour, protein flour or lignocellulosic fibers. #CMT#EXAMPLE : #/CMT# A mixture of L-lactic acid and succinic acid (containing 1-5 mol.% of lactic acid) and tin octoate (0.1-2 wt.%) was heated at 160-190[deg]C. The resultant mixture was placed under reduced pressure to eliminate water produced by the condensation reaction under 800 mbar that was reduced to 20 mbar during the course of the reaction, to obtain lactic acid and prepolymer. The resultant prepolymer was introduced into a glass and carried to 150-190[deg]C. The extension agent 1,3-phenylene-bis-(2-oxazoline) was added in the mixture after one minute to obtain polylactic acid having an acid index of 3.5 mgKOH/g.