水性聚氨酯乳液的制备及其在含硝胺推进剂中的应用

以甲苯二异氰酸酯(TDI)、聚氧化丙烯二醇DL-400(Mn=340)、二羟甲基丙酸(DMPA)为主要原料,保持起始时n(NCO)∶n(OH)=1 7∶1,80℃反应1h,1,4 丁二醇(BDO)扩链,水中分散,制得水性聚氨酯乳液PU-1;运用FTIR、1HNMR表征了其结构;采用GPC测定了PU-1的数均相对分子质量Mn为32122,重均相对分子质量Mw为82785,可用作粘附剂。将合成的PU-1乳液应用于复合固体推进剂(NEPE),采用加入十二水硫酸铝钾(明矾)水溶液〔m(明矾)∶m(水)=1∶10〕沉降乳液的方法包覆氧化剂填料黑索今(RDX),使其形成微胶囊;采用SEM观察了包覆结果,发现包覆后的RDX表面圆滑,包覆后的RDX之间流散性较好。通过撞击感度实验,表明包覆后RDX的撞击感度比包覆前下降了28%;通过外壳溶出实验,测得包覆后RDX中聚氨酯包覆层的质量占样品总质量的1 48%,符合军用标准。水性聚氨酯乳液可作为包覆壁材应用于NEPE推进剂中。

Preparation of Waterborne Polyurethane Latex and Its Application in Nitramine Energetic Propellants

Waterborne polyurethane latex PU-1 was prepared by reacting toluenediisocyanate,polypropylene glycol DL-400(M_n=340) and 2,2-dimethylolpropionic acid〔initial n(NCO)∶n(OH)=1.7∶1〕 at 80 ℃ for 1 h.Then butane-1,4-diol was added as chain extender and the product was dispersed in distilled water and characterized by FTIR and~1HNMR.Determined by GPC,M_n of PU-1 was 32122 and M_w was 82785,which were large enough to be used as adhesive.Used in NEPE propellant,as coating film of RDX,PU-1 latex was deposited by adding alum solution〔m(alum)∶m(H_2O)=1∶10〕to microencapsulate RDX.The coating results were observed through SEM,which indicated that the surface of coated RDX was covered with vivid and pliable film.Impact sensitivity experiment indicated that the sensitivity of RDX coated with PU-1 decreased by 28% than that before coating.By dissolving the shell,mass ratio of coating polyurethane film to sample was determined as 1.48%,accordant with military standard.So latex of waterborne polyurethane can be used as cliff material to coat stuffing in NEPE propellant.