聚醚二醇对耐低温聚氨酯弹性体性能的影响研究

使用2,4-甲苯二异氰酸酯(TDI)、聚醚二醇、3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)等为原料,通过预聚体法制备了一种密封件用聚氨酯弹性体。研究了不同聚醚二醇、扩链剂、增塑剂用量以及预聚体NCO含量对聚氨酯力学性能和低温性能的影响。结果表明:使用3-甲基四氢呋喃/四氢呋喃共聚醚二醇(3MCPG系列)的聚氨酯弹性体的低温弹性优于聚四氢呋喃型聚氨酯的,-40℃下的压缩耐寒系数可达0.43以上;NCO质量分数为4.0%的3MCPG-1410-TDI预聚体以异氰酸酯指数1.1用MOCA扩链,可制得综合性能优良的聚氨酯弹性体;动态力学分析数据证明,在3MCPG-MOCA-TDI聚醚型聚氨酯中,软段玻璃化转变温度可低达-51℃。

Study on Effect of the Polyether Diols on Low Temperature Properties of Polyurethane Elastomers

Some polyurethane elastomers(PUEs)for a seal were prepared from 2,4-toluene diisocyanate(TDI),polyether glycol,and 3,3′-dichloro-4,4′-diaminodiphenylmethane(MOCA),etc by prepolymerization process.The effects of different polyether glycols,chain extenders,plasticizer content and NCO content in the prepolymer on the mechanical properties and low temperature properties of the PUE materials were studied.The results showed that the low-temperature elasticity of PUEs based on 3-methyltetrahydrofuran/tetrahydrofuran copolyether glycol(3MCPG)were better than that of polytetrahydrofuran glycol(PTMG)based PUE,and the compression cold resistance coefficient at-40℃could reach above 0.43.The PUE which prepared by 3MCPG-TDI prepolymer(NCO content was 4.0%)chain-extended with MOCA under isocyanate index of 1.1 had excellent comprehensive properties.DMA data proved that the glass transition temperature of the soft segment in 3MCPG-MOCA-TDI PUE could be as low as-51℃.