新型混炼可降解聚氨酯的制备及可降解行为

Preparation,modification and its degradation behavior of novel degradable PU composites from DTPUP and MPU

以聚四氢呋喃醚二醇(PTMG-1000)、甲苯-2,4-二异氰酸酯(TDI)和甲基丙烯酸羟乙酯(HEMA)为原料,制备出双键封端的聚氨酯预聚物(DTPUP)。将混炼型聚氨酯橡胶(MPU)与DTPUP、炭黑、硫化剂共混制备出新型可降解聚氨酯密封材料,研究了DTPUP的用量对材料的力学性能、降解行为及热稳定的影响。结果表明,在混合体系中,随着DTPUP相对含量的增加,可降解聚氨酯复合材料的拉伸强度表现出先增加后降低的趋势,当DTPUP用量为20份时,拉伸强度出现极值27.3 MPa;随着DTPUP含量的增加及浸泡时间的延长,复合材料的降解速率越慢,DTPUP用量低于20份时,在72 h内完全失去力学性能,DTPUP用量高于20份时,材料的力学性能可维持至100 h以上;随着DTPUP含量的增加,长链软段的热降解温度及最大降解速率温度均升高,提高了材料的热稳定性。

In this study,the double bond terminated polyurethane prepolymer(DTPUP)was prepared by using poly(tetramethylene ether glycol)(PTMG-1000),toluene-2,4-diisocyanate(TDI)and hydroxyethyl methyl acrylate(HEMA)as raw materials.A novel degradable PU sealing material was prepared by blending millable polyurethane rubber(MPU)with DTPUP,carbon black and vulcanizing agent.The influence of the content of DTPUP on the mechanical properties,degradation behavior and thermal stability of the material was investigated.The results showed that in the mixed system,the tensile strength of the degradable polyurethane composites increases first and then decreases with an increase of DTPUP in content.When the DTPUP content is 20 parts,the tensile strength shows an extreme value of 27.3 MPa.With the extension of immersion time,the degradation rate of the material decreases with an increase of DTPUP in content.When the DTPUP content is less than 20 parts,the mechanical properties were completely lost within 72 hours.When the DTPUP content is higher than 20 parts,the mechanical properties of the material can be maintained up to 100 hours or more.The thermal degradation temperature of the long-chain soft segment increases and the maximum degradation rate temperature increases with an increase of DTPUP in content,which improved the thermal stability of the material.