聚氨酯弹性体的形态结构和电性能研究不同起始反应温度的影响  

Morphology and Electrical Insulating Property of Polyurethane Elastomers Infulunce of Different Startimg Reaction Temperatures

作　　者：宁超峰[1] 王得宁[1] 胡春圃[1] 

机构地区：[1]华东理工大学材料科学与工程研究所,上海200237

出　　处：《功能高分子学报》2000年第3期261-265,共5页Journal of Functional Polymers

摘　　要：以聚醚多元醇、丁二醇和甲苯二异氰酸酯为原料 ,在不同起始反应温度下 (不用催化剂 )合成了一系列硬段含量为 30 %的聚氨酯弹性体 (PU) ,它们的起始反应温度分别为 2 0℃ (S -1 )、40℃ (S -2 )、6 0℃ (S -3)和 80℃ (S -4 )。用示差扫描量热分析、傅立叶变换红外光谱和透射电镜研究了它们的形态结构。研究结果发现 :随着初始反应温度的升高 ,试样S -1的相分离程度较大 ,S -2次之 ,S -3的相分离程度较小 ,但S-4的相分离程度又有升高的趋势 ,这可能是在合成过程中物料粘度以及网络结构的形成与硬段聚集成微区的速度不同所造成。用正电子湮没寿命谱研究了PU的自由体积特性 ,发现S -3的自由体积孔穴最小 ,相对自由体积浓度最高 ,但相对自由体积分数最低。进一步研究表明 ,S -3的电阻率也最高。由此可见 ,PU的形态结构与自由体积特性和材料的电性能密切相关。Some PU elastomers with the hard segment content of 30% by weight, were prepared based on polyether polyol, butanediol and toluene diisocyanate at different starting reaction temperatures, i.e. 20 ℃ (sample S-1), 40 ℃ (sample S-2), 60 ℃ (sample S-3) and 80 ℃ (sample S-4) respectively. Their morphology was observed by means of differential scanning calorimetry, Fourier transform infrared spectroscopy and transmission electron microscope. The results indicated that the degree of phase separation (DPS) of sample S-3 was the lowest, the DPS of sample S1 was the highest, and the DPS of sample S-2 and sample S-4 was between them. The reason of these different morphologies might be attributed to the different viscosity of raw materials and the different rates between the formation of the networks and the aggregation of hard segments to domains in the synthesis process of PU elastomers. The free volume existing in PU elastomers was measured by using positron annihilation spectroscope. It was indicated that there was a minimum size of free volume and a maximum relative free volume concentration for sample S-3, but the lowest relative free volume fraction for S-3 was found. The electrical resistivity of PU elastormers was also studied, sample S-3 had the highest electrical resistivity. So the morphology and the free volume of PU should have some relation with their electrical insulating properties.

关 键 词：聚氨酯弹性体 电性能 形态结构 聚醚多元醇 合成 

分 类 号：O633.14[理学—高分子化学] O631.23[理学—化学]