催化剂陈化温度和用量对环氧乙烷聚合稳定性的影响

Polymerization of ethylene oxide over catalyst with different aging temperature and usage weight

摘要:

本文采用以碱土金属氨钙为催化剂合成水溶性聚合物——聚氧化乙烯（PEO），研究了催化剂陈化温度和用量对催化剂聚合效果的影响。研究表明，陈化温度对催化剂聚合收率的影响较小，但明显影响对聚合物分子量的波动程度有明显影响；其中60℃陈化的催化剂表现最为稳定，不仅聚合收率可以保持在99%以上，且不同批次间聚合物的分子量差异波动程度（以变异系数表示）也能降至最低值，达到7.3%。通过改变催化剂用量，可以在高聚合收率的前提下，稳定地合成出不同分子量级别（4039万至86万）的PEO。SEM（扫描电镜）、XRD（X射线衍射）和DSC（示差扫描量热法）的表征结果进一步结果表明，所得PEO粉末颗粒是一种具有层状结构的部分结晶性聚合物，且结晶度随分子量的增加而增加。

Abstract:

The effects of aging temperature and weight usage of calcium-ammonia catalyst on the polymerization reaction of ethylene oxide for to polyethylene oxide (abbr. as PEO) synthesis wasere investigated. It showed that the aging temperature did not influenced the catalytic yield of PEO littleobviously, but determined the stability of polymerization significantly. Herewhich the stability of polymerization was measured by the variable coefficient of molecular weight of synthesized PEO products on the catalysts prepared at prepared at the same conditions. It exhibited a volcano shape with increasing the aging temperature, and Comparatively, the catalyst aged at 60℃ seemed was most stable, on in which the variable coefficient of molecular weight of PEO can be decreased to 7.3%, as well as the yield of PEO maintained at higher more than 99%. Furthermore, a series of PEO samples with a meanthe molecular weight of PEOs from 4.03.9 ×105 g/mol to 8.6 ×105 g/mol can be was synthesized controllably by changing the catalyst usage. Moreover, Bby characterizations of SEM, XRD and DCS, it was testified that the synthesized PEO was one kind ofpresented a kind of layered and partially crystallized polymers, and the crystalline degree increased with increasing the molecular weight of PEO.