Interfacial reinforcement of core-shell HMX@energetic polymer composites featuring enhanced thermal and safety performance

The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves the pretreatment of HMX to endow—OH groups on the surface via polyalcohol bonding agent modification and in situ coating with nitrate ester-containing polymer,was proposed to address the problem.Two types of energetic polyether—glycidyl azide polymer(GAP)and nitrate modified GAP(GNP)were grafted onto HMX crystal based on isocyanate addition reaction bridged through neutral polymeric bonding agent(NPBA)layer.The morphology and structure of the HMX-based composites were characterized in detail and the core-shell structure was validated.The grafted polymers obviously enhanced the adhesion force between HMX crystals and fluoropolymer(F2314)binder.Due to the interfacial reinforcement among the components,the two HMX-based composites exhibited a remarkable increment of phase transition peak temperature by 10.2°C and 19.6°C with no more than 1.5%shell content,respectively.Furthermore,the impact and friction sensitivity of the composites decreased significantly as a result of the barrier produced by the grafted polymers.These findings will enhance the future prospects for the interface design of energetic composites aiming to solve the weak interface and safety concerns.

Research and Application of Anti-Collapse Lubricant Compound Polyalcohol for Water-Based Drilling Fluid

Polyalcohol is an environmentally friendly anti-collapse lubricant commonly used in water-based drilling fluids. It is generally composed of the single polyether or polyol, but its lubricity and anti-collapse inhibition can’t satisfy the application of current water-based drilling fluid systems well. Consequently, the laboratory has carried out research on the anti-collapse lubricant compound polyalcohol. The anti-collapse lubricant samples are mixed with lauryl polyether, nonylphenol polyether and Tween 80 according to different proportions. The cloud point, the reduction rate of lubrication coefficient and linear expansion are measured, and the change they caused should be observed. Then, the optimal ratio is optimized through orthogonal experiments. The results show that the increase in the content of the three kinds of polyethers respectively enhances the inhibition. When the content of lauryl polyether increases, the cloud point of the anti-collapse lubricant declines and the reduction rate of lubrication coefficient rises;when the content of nonylphenol polyether increases, the cloud point declines, but it has little effect on the reduction rate of the lubrication coefficient;when the content of Tween 80 increases, the cloud point rises, and the reduction rate of the lubrication coefficient first augments and then basically remains unchanged. The best mass ratio of lauryl polyether:TW-80:nonylphenol polyether is 6:3:4.