一种PPG型聚氨酯弹性体的制备及性能

Preparation and properties of PPG/TDI-100/DMTDA casting polyurethane elastomer

以聚丙二醇(PPG)、甲苯二异氰酸酯(TDI-100)和3,5-二甲硫基甲苯二胺(DMTDA)为原料制备了5种不同预聚体—NCO基含量分别为3.94%、4.54%、5.12%、5.68%、6.24%的浇注型聚氨酯(CPU)弹性体。对CPU弹性体的力学性能和维卡软化点进行表征分析,结果表明,PPG/TDI-100/DMTDA体系随着—NCO含量的增加,其拉伸强度、撕裂强度、硬度逐渐增大,扯断伸长率下降。随着扩链系数的增加,CPU的断裂伸长率增加,拉伸永久变形增加,硬度和回弹基本不变;扩链系数在0.85时,CPU弹性体的拉伸强度最高;扩链系数为0.98时,撕裂强度最大可达到68kN·m-1。—NCO基含量越高的CPU弹性体具有的抗热变形性能就会越好。当—NCO含量为6.42%时维卡软化点温度达到114℃。

In this paper,five types of prepolymers with various—NCO content from 3.94% to 6.24% were respectively synthesized through preploymer method using polypropylene glycol（PPG）,toluene diisocyanate（TDI-100）and 3,5-dimethyl thiotoluene diamine（DMTDA）.Mechanical properties,vicat softening point and infrared structure of CPU elastomer were tested.Results showed that with the increase of—NCO content,hardness,tensile strength and tear strength of the CPU elastomer increased.With the increase of crosslink coefficient,elongation at break and permanent deformation increased,but hardness and impact resilience remained unchanged.When crosslink coefficient was 0.85,the tensile strength of CPU elastomer was maximum.When crosslink coefficient was 0.98,the maximum value of tear strength was 68 kN/m.With the increase of—NCO content of prepolymer,the CPU elastomer had higher resistance to thermal deformations.When—NCO content of prepolymer was 6.24%,vicat softening temperature rose up to 114 ℃.