具有超支化结构的聚醚型脂肪族聚氨酯弹性体的合成与表征及力学性能研究

SYNTHESIS,CHARACTERIZATION AND MECHANICAL PROPERTIES OF POLYETHER-BASED ALIPHATIC POLYURETHANE ELASTOMERS COMPOSED OF HYPERBRANCHED POLYESTER SEGMENTS

用聚四氢呋喃醚二醇、端羟基超支化聚酯(HB-20)、异佛尔酮二异氰酸酯和1,4-丁二醇,合成了含有超支化结构的聚醚型脂肪族聚氨酯(PU)弹性体.通过Flory-Rehner公式计算了体系的交联密度;用FT-IR、WAXD和DSC表征了超支化PU的氢键化程度和形态.实验结果表明,在PU弹性体中引入少量的HB-20,能提高氨基甲酸酯羰基的氢键化程度和软硬段间的微相分离程度,从而显著提高材料的拉伸强度.由于氢键化程度和交联密度双重效应的影响,含6 wt%HB-20的聚醚型PU与不含HB-20的PU相比拉伸强度提高了2倍多,达到37.9 MPa,断裂伸长率仍高达414%.

Aliphatic polyether-based polyurethane （PU） elastomers with hyperbranched polyester segments were synthesized by prepolymer process from polytetramethylene ether glycol, hydroxyl-terminated hyperbranched polyester （HB-20）, IPDI and 1,4-butanediol. The crosslinking density of the PU elastomer was calculated by using the Flory- Rehner equation. The degree of hydrogen bonding, the microstrueture and the morphologies of these PU materials were characterized by means of FTIR, WAXD and DSC, respectively. The experimental results indicated that the PU elastomers containing small amount of HB-20 exhibited the enhanced hydrogen bonding and the micro-phase separated morphologies as well as the mechanical properties. As compared with the comparable PU specimen, the tensile strength of the polyether-based aliphatic PU containing 6 wt% HB-20 increased by 2.1 times, up to 37.9 MPa, and the elongation at break was still as high as 414%, resulting from the dual effects of the hydrogen bonding and the crosslinking density in the PU system.