Method for preparing high molecular weight biodegradable polyester by combined chain extension
A biodegradable, high-molecular-weight technology, applied in the field of preparation of aliphatic polyesters, can solve the problems of time-consuming, complicated operation, high degree of reaction, etc., and achieve the effects of high molecular weight, simple preparation method, and reduced consumption
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Embodiment 1
[0042] Embodiment 1: the preparation of polybutylene adipate (PBA) prepolymer: with 50 parts of adipic acid, 31 parts of butanediol in parts by weight, 0.24 part of dibutyl tin oxide, 0.08 part of phosphorous acid, Under the protection of nitrogen, gradually increase the temperature from 160°C to 200°C for polycondensation reaction. After collecting 70-80% of the generated water, use a decompression device. First, use a water pump to gradually depressurize the reaction for 3-4 hours, and then use an oil pump to depressurize. Reduce the pressure to 1 mmHg, and continue to react for 3 to 4 hours at a temperature range of 190 to 210 °C until the acid value remains basically unchanged. The number average molecular weight is 4300, the intrinsic viscosity is 0.35 dL / g, and the acid value is 36.2 mgKOH / g. A PBA prepolymer with a hydroxyl value of 8.4 mgKOH / g.
Embodiment 2
[0043] Embodiment 2: 100 parts by weight of PBA oligomers prepared in Example 1 (the number average molecular weight is 4300), 2.6 parts of N, N'-adipyl biscaprolactam, 6.9 parts of 1,4-phenyl-biscaprolactam (2-oxazoline), react under reduced pressure at 180° C. for 3 hours under the protection of nitrogen, and the number average molecular weight of the obtained polymer is 11860.
Embodiment 3
[0044] Example 3: Referring to Example 2, the chain extension temperature was changed to 200°C, and the other conditions were exactly the same. The number average molecular weight of the obtained polymer was 25740, the Mw was 159398, and the intrinsic viscosity was 0.87dL / g.
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