To improve the toughness of the semi-rigid chain of nitrocellulose (NC), and to avoid the phenomenon of small molecule gas generated by isocyanate polycondensation reaction in the curing of propellant, glycidyl azide polymer (GAP)-hexamethylene diisocyanate (HDI)-NC (GAP-HDI-NC) graft polymer and its click reaction elastomer were successfully fabricated by azide-alkyne cycloaddition click reaction in this contribution. In addition, the formulations of GAP-HDI-NC graft polymer and its elastomer were optimized on the basis of improving the mechanical properties, thermal stability and safety. With the increasing of GAP content, the peak value of α transition at high temperature increases, that is, mechanical loss increases and tensile strength decreases. When the mass ratio of GAP to NC is 45:55, the tensile strength (σ_m) and breaking elongation (ε_b) of GAP-HDI-NC graft polymer are 44.1 MPa and 58.7% respectively, and the Tg₁ of GAP-HDI-NC click reaction curing elastomer reaches the minimum value of 105.7 °C, which is much lower than that of pristine NC. When R₂ value is 1.0, the σ_m of GAP-HDI-NC click reaction curing elastomer reaches the maximum value of 47.6 MPa, while when R₂ value is 0.9, its ε_b reaches the maximum value of 55.8%. In addition, the click reaction of azide group is beneficial to improve the thermal stability and safety performance of GAP-HDI-NC click reaction curing elastomer, which has good potential as solid propellant binder.

Graphical abstract

中文翻译：

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叠氮改性硝酸纤维素及其点击反应固化弹性体的制备及性能

为提高硝化纤维素（NC）半刚性链的韧性，避免推进剂固化过程中异氰酸酯缩聚反应产生小分子气体的现象，采用叠氮缩水甘油酯聚合物（GAP）-六亚甲基二异氰酸酯（HDI）-NC (GAP-HDI-NC) 接枝聚合物及其点击反应弹性体通过叠氮化物-炔烃环加成点击反应成功制备。此外，在提高力学性能、热稳定性和安全性的基础上，对GAP-HDI-NC接枝聚合物及其弹性体的配方进行了优化。随着GAP含量的增加，高温α转变峰值增加，即机械损失增加，抗拉强度降低。当 GAP 与 NC 的质量比为 45:55 时，抗拉强度 ( σ_{GAP-HDI-NC接枝聚合物的m} )和断裂伸长率( ε _b )分别为44.1 MPa和58.7%，GAP-HDI-NC点击反应固化弹性体的Tg ₁达到最小值105.7 ℃，即远低于原始NC。当R ₂值为1.0时，GAP-HDI-NC点击反应固化弹性体的σ _m达到最大值47.6 MPa，而当R ₂值为0.9时，其ε _b达到最大值 55.8%。此外，叠氮基的点击反应有利于提高GAP-HDI-NC点击反应固化弹性体的热稳定性和安全性能，具有良好的作为固体推进剂粘合剂的潜力。

图形概要