Synthesis And Characterization On Mesoporous Energetic Materials Based On GAP

Azido polymers which was used as energetic material binder in propellant was a kind of good skeleton materials to prepare the nano-composite energetic materials which had positive enthalpy of formation, good stability, low flame temperature, high nitrogen content and environmental friendly.However, it was easy to collapse and the structure of the internal pore was uncontrollable for the organic skeleton. Hence, in this study, the porous energetic materials used GAP(poly(azide glycidyl ether) as whose pore structure could be controlled were synthesed by amphiphilic block copolymers self-assembly and alkaline etching method, and polystyrene was added to improve the stability of the skeleton to avoid the collapse of the pore. Finaly, the structure and properties of the porous materials were characterizated,which will lay the foundation for in situ polymerization to prepar nano-composite energetic materials.Therefor, it has strong theoretical significance and practical application prospect.The macroinitiator GAP(poly(azide glycidyl ether))-Br, one side of which was hydroxyl group, the other was alkyl bromide group was synthesed by bromine replaced reaction with bromoacetyl bromide and 2-bromine butyryl bromine respectively using GAP(Mn =4000,f=2.1)as precursor. The structure of the GAP-Br macroinitiator was characterized by FTIR, 1HNMR, GPC, the hydroxyl content and bromine content of which was 54% and 46%.GAP(poly(azide glycidyl ether))-Polystyrene(GAP-PS) block copolymers with diffeverent block ratio of GAP and PS as 40:15 ~ 40, the range molecular weight of which from 6000 to 8000 and molecular weight distribution from 1.13 ~ 1.37 were synthesized through atom-transfer radical polymerization of styrene in the presence of a macroinitiator mGAP-Br.Polylactide-b-poly(azide glycidyl ether)-polystyrene(PLA-b-GAP-b-PS) with range molecular weight from 8000 to 10000 and molecular weight distribution from 1.20 ~ 1.40 were synthesized through insert coordination polymerization. The best synthesis condition was received, the azide group would be disintegrated when the amount of substance of catalyst stannous octylic acid was 50 times than hydroxyl of GAP; the reaction times should be cotrolled between 25 to 30 h.The impact of different organic solvents on PLA-b-GAP-b-PS triblock copolymers were studied,the results show that the morphology of micelles self-assembled in toluene was regular spherical structure as three layers of the onion and the sizes of these micelles changed with diffeverent concentrations. The average size of the micelles from 50, 100, 250 nm when the concentration was 5, 10,15 mg/ml respectively.The mesoporous materials were achieved for eatching the self-assembled block polymers in alkaline liquid. The influence of the eatching solution, concertration of self-assembled block polymers, the content of PLA, the order of alkaline liquid on the pore structure was studied. The results show that sodium dodecyl sulfate(SDS) which was added in the alkaline liquid played a significant role in the degradation of PLA; the higher the concertration of the block copolymers, the larger the aperture; the quantity of the hole was reduced while the aperture was increased when the content of PLA was decreased; the shape of the holes was regular circle when the alkaline liquid was added before the toluene was evaporated.