高聚物黏结剂对HMX相变行为的影响

Effects of Binders on the Phase Transition Behavior of HMX

为了探究高聚物黏结剂对奥克托今(HMX)相变行为的影响,使用压装成型工艺制备了含聚酯型聚氨酯(HMX⁃Estane)、氟橡胶(HMX⁃F_(2314))、硝化纤维素(HMX⁃F_(2314)⁃NC)的HMX基高聚物黏结炸药以及纯HMX药柱,利用原位变温X射线广角散射(WAXS)技术和差示扫描量热法,研究了热刺激下样品中HMX的相变行为和机制。WAXS结果表明,HMX⁃Estane(95∶5)、HMX药柱、HMX⁃F_(2314)(95∶5)、HMX⁃F_(2314)⁃NC(95∶3∶2)的相变起始温度(T_(i))分别为186℃、188℃、192℃、198℃。相比于HMX药柱,黏结剂中加入少量的NC(2%),T_(i)可提升10℃。真空条件下,4种样品从高温δ相降温至100℃保温,只有HMX⁃Estane发生了δ→β逆相变且在3.5 h内δ相全部转变为β相,而其他样品均未发生相变,仍为δ相。β⁃HMX在HMX⁃Estane界面位置的溶解(升温过程)和析出(降温过程)可能是促进HMX⁃Estane发生β→δ相变,及其逆相变的主要因素。

The phase transition behavior of HMX⁃based polymer⁃bonded explosives(PBX)and pure HMX pellet,prepared by compression molding,was studied by variable temperature wide⁃angle X⁃ray scattering(WAXS)and differential scanning calo⁃rimetry(DSC).The HMX⁃based PBX contained polyester polyurethane(HMX⁃Estane),fluororubber(HMX⁃F_(2314)),as well as ni⁃trocellulose(HMX⁃F_(2314)⁃NC).The initialβ→δphase transition temperatures(T_(i)),as determined by WAXS,were found to be 186℃for HMX⁃Estane(95∶5),188℃for HMX pellet,192℃for HMX⁃F_(2314)(95∶5),and 198℃for HMX⁃F_(2314)⁃NC(95∶3∶2).The addition of the small amount of nitrocellulose(2%)to the binder increased the T_(i) by about 10℃,compared with HMX pel⁃let.All samples retained theδ⁃phase when cooled from the high temperature phase to 100℃and kept in vacuum for 12 h,ex⁃cept HMX⁃Estane which went through a reversible phase transition and changedβphase completely after kept at 100℃for 3.5 h.Among the three types of binders only Estane promoted theβ→δphase transition and the reversedδ→βtransition of HMX.This result was attributed to the dissolution(on heating)and the precipitation(on cooling)ofβ⁃HMX at the HMX⁃Estane interface.