亲水链段PEG分子量对水性聚氨酯浇铸膜结晶性的影响  

Effect of PEG Molecular Weight in Hydrophilic-segment on the Crystallization of Cast Film of Water-borne Polyurethane

作　　者：宋晓晖[1] 周善康[1] 许一婷[1] 何云游 戴李宗[1] 

机构地区：[1]厦门大学材料科学与工程系,福建厦门361005

出　　处：《厦门大学学报（自然科学版）》2002年第4期463-467,共5页Journal of Xiamen University：Natural Science

摘　　要：采用二级扩链技术 ,合成了同时具备阴离子型和非离子型大分子链结构的水性聚氨酯分散液 .以红外光谱技术 ,就预聚反应时间和温度对反应程度的影响进行了表征 ,认为当初始合成温度为 70℃时 ,以丁酮为稀释剂、DMPA为离子型亲水单体、乙二醇为一级扩链剂、三乙胺为中和剂、三乙烯四胺为二级扩链剂 ,控制nNCO/nOH=1.3,预聚反应 5h ,扩链反应 2～ 4h ,可获得具有良好稳定性的水性聚氨酯分散液 .采用XRD、DSC等技术 ,研究了亲水链段PEG分子量对水性聚氨酯浇铸膜结晶性的影响 ,证实了所合成的水性PU结晶形态属于单斜晶系 。The polyurathane are the segmented copolymers that consist of alternating soft and hard segment units. In order to obtain a better synthesizing way of water borne polyurethane (WBPU) dispersion, the WBPU whose macromolecular chain structure combined of anionic and nonionic types was prepared by a new technology of second order expanded chain. Quasi quantitative analytical method of FTIR spectra was adopted to characterize the effect of pre polymerization's condition(time & temperature)on pre polymerization's process, and the stable WBPU dispersion was obtained in the following optimal condition: 70 ℃, dimethylolpropionic acid(DMPA) as ionic hydrophilic monomer, polyethylene glycol(PEG) as first order expanded chain agent, triethylamine(TEA) as neutralizing agent, triethylenetetramine (TETA) as second order expanded chain agent, n NCO /n OH =1.3, prepolymerization period 5 h, and expanded chain period 2～4 h. It was indicated by test of forming cast film that it was easy to form cast film with higher PEG molecule weight. Wide angle X ray diffraction (XRD), differential scanning calorimetric (DSC) methods were used to study the effect of PEG molecular weight in hydrophilic segment on the crystallization of WBPU cast films. The results indicated that crystal form of WBPU was monoclinic, and along with the PEG molecule weight increased, the percentage of soft segment and molecular chain pliancy increased resulting in higher crystallinity and tightness.

关 键 词：亲水链段PEG 分子量 浇铸膜 水性聚氨酯 合成 结晶性 结晶微区 晶胞参数 聚乙二醇 二级扩链技术 

分 类 号：O633.14[理学—高分子化学]