高沸醇木质素聚氨酯的合成及其性能

Synthesis and Properties of HBS Lignin Modified Polyurethane

利用高沸醇（High Boiling Solvent，HBS）木质素替代部分聚醚二元醇直接与甲苯二异氰酸酯（TDI）合成聚氨酯。对木质素聚氯酯样片的力学性能和耐溶剂性能进行了研究，并进行了热重（TG）分析。结果发现，当w（木质素）〈10％时，聚氨酯有良好的弹性。而拉伸强度低于10MPa；w（木质素）=15％～25％时，聚氨酯的拉仲强度提高到16MPa或更高，其溶胀质量增加率降到84％以下；木质素聚氨酯的拉伸强度随n（NCO）／n（OH）值的增大而迅速增强；当w（木质素）〉30％时，无论n（NCO）／n（OH）值为多少都得到了硬、脆的聚氨酯；采用相对分子质量较低的聚醚二元醇合成的木质素聚氨酯的拉伸强度可提高到36MPa以上，其断裂伸长率并不明显降低．甚至在n（NCO）／n（OH）〈1．6时反而更高，而溶胀质量增加率则降到1．25％。热重（TG）分析表明，HBS木质素的引入提高了聚氨酯的耐热性，其400℃以下的分解百分率下降了12．94％。

HBS（ high boiling solvent） lignin modified polyurethane was directly prepared by solution casting with polyether glycol and toluene diisoeyanate （TDI）. Flexible but weak polyurethane were obtained at lignin mass fraction lower than 10%. When the lignin mass fraction increased to 15-25% , rather tough polyurethane were prepared, while the tensile strength was raised to 16 MPa and the swelling weight gain mass fraction decreased to 84%, When lignin mass fraction was higher than 30% , hard and brittle polyurethane were obtained irrespective of the NCO/OH molar ratio. When using low molecular weight polyether glycol, the tensile strength of HBS lignin modified polyurethane could be raised up to 36 MPa and the swelling weight gain mass fraction even decreased to 1.25% while the ultimate strain doesn＇t lower much or even increased at NCO/OH molar ratio 〈 1.6. Based on the TGA graphs,the lowering of degradation ratio of polyurethane below 400 ℃（from 92.21% to 79.27% ） showed that HBS lignin gave polyurethane relatively better heat resistance.