Synthesis And Properties Of 2,6-Dinitro-1,4-Diphenmethyol Thermoplastic Elastomer

Melt-cast explosives generally have the problems of high brittleness and poor mechanical properties.In order to improve these problems,many researches on mechanical modification have been carried out at home and abroad.By studying the effect of modifier molecules and molten cast explosive components on the mechanical properties of molten cast explosives,summarizing the toughening mechanism of modifiers in molten cast explosives can provide a theoretical basis and guidance for the selection and preparation of toughening modifiers.In this thesis,two GAP-based energetic thermoplastic elastomers(GAP-ETPE)with different structures have been designed and synthesized with 2,6-dinitro-1,4-diphenmethyol as the initiator or chain extender,and they have passed structural characterization and performance testing,etc.It is proved that it has the potential as an energetic binder.(1)A new energetic polymer with GAP as a flexible segment,2,6-dinitro-1,4-diphenmethyol and MDI as a hard segment for melt-cast explosives was prepared: 2,6-dinitro-1,4-diphenmethyol GAP-ETPE.The glass transition temperature of GAP-ETPE is-18 ?,the maximum exothermic peak appears at 260.5 ?,and the exotherm is 1725 J/g.The tensile test showed that when R=0.98 and the hard segment mass fraction is 35%,2,6-dinitro-1,4-diphenmethyol GAP-ETPE has better performance.Mechanical experiments show that when 1.0% 2,6-dinitro-1,4-diphenmethyol GAP-ETPE is added to hexolite,the compressive load,compressive strength and compressive deformation increase by 7.1%,9.8%,and 22.5%,respectively.Through quantum chemistry,2,6-dinitro-1,4-diphenmethyol GAP-ETPE and TNT interaction simulation calculation.Experiments and computational simulations show that 2,6-dinitro-1,4-diphenmethyol GAP-ETPE has the potential to become a toughening modifier for hexolite.(2)The sorbitol GAP-ETPE was prepared using sorbitol,epichlorohydrin,sodium azide and 2,6-dinitro-1,4-diphenmethyol through a three-step method of etherification,azide and chain extension.The experimental results showed that with the amount of fixed catalyst and epichlorohydrin,as the amount of sorbitol increased,the corresponding degree of etherification increased greatly.The generated glycidyl ether molecules are larger;however,a further increase in the amount of sorbitol is equivalent to a decrease in the proportion of epichlorohydrin,which will reduce the degree of etherification,and the generated glycidyl ether molecules will become smaller.The experiment shows that when the R value is 0.98 and the hard segment mass fraction is 20%,the elastomer mechanical properties are better,and it is found that the glass transition temperature of sorbitol GAP-ETPE is-26.3 ? under this condition,and there are two obvious releases at 312.6 ? and 607 ?.The heat peak and the decomposition heat corresponding to the integral calculation are 450 J/g and 1483J/g,respectively.Experiments show that sorbitol GAP-ETPE has the potential as an energetic binder.(3)In order to verify the possibility of hydroxyl-terminated polymer as a chain extender,2,6-dinitro-1,4-diphenmethyol GAP was selected as the chain extender,and the chain extension reaction of sorbitol GAP was obtained,and a new Sorbitol GAP-ETPE with hard segment structure.The glass transition temperature is-26.5 ?,and three exothermic peaks appear at 240.7 ?,311.3 ? and 609 ?.The corresponding decomposition heats of integral calculation are 100.1 J/g and 405.8 J/ g and 2329 J/g.It has good thermodynamic properties,high decomposition temperature,and the maximum heat of decomposition is much larger than the maximum heat of decomposition of the first two.It has the potential to be used as an energetic binder.