Process for purifying lactide formed through ring-opening polymerization
A technology of ring-opening polymerization and purification method, which is applied in the production field of cyclic diesters, can solve the problems such as insufficient effect, and achieve the effects of excellent purification yield, excellent biodegradability and heat resistance
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Embodiment 1
[0138]In a polymerization vessel equipped with a stirring device and nitrogen inlet and outlet pipes, a toluene solution of 20.0 g of L-lactide, 114 g of stearic acid and 6 mg of tin(I) octoate was added to obtain a mixture. The mixture was dried under reduced pressure for 2 hours, and then heated to 200° C. under a small nitrogen stream to carry out ring-opening polymerization. The reaction mixture became viscous immediately. After 1 hour the reaction was complete and the polymer was removed from the reaction vessel.
[0139] The resulting polymer had a reduced viscosity of 1.70, a temperature at 10% weight loss of 321°C and a melting point of 177°C. The polymer exhibited satisfactory melt stability (i.e. VMR = 95%), and d-chloroform was used as solvent for the polymer 1 H-NMR spectrum analysis, the result confirmed that there is a terminal stearyl peak (1.23ppm).
Embodiment 2
[0141] A polymer was prepared in the same manner as in Example 1 except that 20.0 g of L-lactide and 228 mg of stearic acid were used.
[0142] The reduced viscosity of the obtained polymer was 0.84, the temperature at 10% weight reduction was 310°C, and the melting point was 176°C. The polymer exhibited satisfactory melt stability (ie VMR = 90%). The polymer was prepared using d-chloroform as solvent 1 H-NMR spectrum analysis, the result confirmed that there is a terminal stearyl peak.
Embodiment 3
[0144] A polymer was prepared in the same manner as in Example 1 except that 20.0 g of L-lactide and 28 mg of stearic acid were used.
[0145] The reduced viscosity of the obtained polymer was 1.77, the temperature at 10% weight reduction was 315°C, and the melting point was 180°C. The polymer exhibited satisfactory melt stability (ie VMR = 96%). The polymer was prepared using d-chloroform as solvent 1 H-NMR spectrum analysis, the result confirmed that there is a terminal stearyl peak.
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Abstract
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