双组分低黏度微孔聚氨酯弹性体的制备与分子调控

Preparation and molecular regulation of two-component microporous polyurethane elastomers with low viscosity

以异佛尔酮二异氰酸酯(IPDI)、聚四氢呋喃二醇(PTMEG)为原料,通过预聚体法合成了端异氰酸酯(—NCO)双组分低黏度微孔聚氨酯(LVMPU)预聚体,以1,4-丁二醇(BDO)、三羟甲基丙烷(TMP)为扩链剂,空气中微量水为发泡剂,室温浇注在模具中静置消泡后在高温下(130℃)反应固化得到双组分LVMPU弹性体。探讨了m(IPDI)∶m(PTMEG)、m(TMP)∶m(BDO)、剩余—NCO含量对双组分LVMPU弹性体性能的影响。结果表明,当m(IPDI)∶m(PTMEG)<5∶6、—NCO含量<2.4%时,得到无—NCO的双组分LVMPU弹性体;当由m(IPDI)∶m(PTMEG)=2∶3制备的预聚体20 g、BDO 2.57 g、—NCO含量为1.4%时,双组分LVMPU弹性体的力学性能最佳;随着—NCO含量的增加,双组分LVMPU弹性体的表面无泡孔结构,截面泡孔逐渐增多,且多为圆形闭孔结构,孔径较大;当m(TMP)∶m(BDO)逐渐增加时,双组分LVMPU弹性体的表面出现大量开孔结构,截面的圆形开孔结构逐渐增多,孔径分布较为均匀,平均孔径降低。

Terminated isocyanate(—NCO)two-component microporous polyurethane with low viscosity(LVMPU)prepolymer was synthesized from isophorone diisocyanate(IPDI)and polytetramethylene ether glycol(PTMEG)by prepolymer method.Then,two-component LVMPU was obtained from curing reaction at high temperature(130℃)after static defoaming at room temperature in the mold using 1,4-butanediol(BDO)and trimethylolpropane(TMP)as chain extenders,and a small amount of water in the air as foaming agent.The effects of m(IPDI)∶m(PTMEG),m(TMP)∶m(BDO),and residual—NCO content on the properties of two-component LVMPU elastomer were further analyzed.The results showed that when the mass ratio of IPDI to PTMEG was less than 5∶6 and the—NCO content was less than 2.4%,two-component LVMPU elastomer without—NCO could be obtained.Under the conditions of 20 g prepolymer prepared with m(IPDI)∶m(PTMEG)=2∶3,2.57 g BDO,and—NCO content 1.4%,the prepared two-component LVMPU elastomer exhibited the best mechanical properties.With the increase of—NCO content,the surface of two-component LVMPU had no cell structure,while the cross-sectional cells increased gradually with most of circular closed-cell structures with large pore sizes.When the mass ratio of TMP to BDO increased gradually,open-cell structures dominated the surface of two-component LVMPU elastomer,and the circular open-cell structures in the cross-section increased gradually,with relatively uniform pore size distribution and reduced average pore size.