The Study Of Functional Additives For The Water Ramjet Engine Propellant

The solid content of the water ramjet engine propellant is up to85%, componentbalance, processing performance and mechanical properties of the propellant areimportant and difficult. We must first solve the processing performance of propellantslurry (pouring, fluidity and long applicable period) to achieve the fuel-rich propellantwhich is high metal content, high solid content and still can pour.Meanwhile, aftercuring the propellant should be maintained good mechanical properties and structuralintegrity. Because of the characteristic which is high metal content and high solidcontent, the interface bond is a key factor to affect the mechanical properties of grain.The object of the thesis was Mg/AP/HTPB water ramjet engine propellan-t.According to the interfacial chemistry, rheology, mechanics of materials and otherrelated principles, functional additives for the water ramjet engine propellant weresynthesized by Radical Polymerization of the Monomers such as acrylic acid(AA),2-Hydroxyethyl acrylate(HEA) and butyl acetate(BA).The best synthesis had befound.By means of Equation of Drago.R.S, the surface acid-base property parameter of themain components in water ramjet engine propellant were characterized by inverse gaschromatography(IGC). We calculated out the enthalpy of interfacial acid-basefunction(△HAB)of the main components.The conclusions showed that the functionaladditives can be preferential adsorbed on the solid filler’s surface, and because of theenthalpy between the functional additives and the Mg or AP is higher than PU matrixand the Mg or AP, also higher than the functional additives and PU matrix.According to contact angle test, the contact angle of Mg, AP and Mg treated withkinds of different functional additives had been detected. The surface tension, polarforce parameter and non-polar parameter of the surface tension and polar fraction havebeen calculated. From the parameters, the interfacial tension, work of interfacialadhesion between the fillers and hydroxyl-terminated polyurethane matrix had beencalculated. The interfacial adhesion properties also had been estimated by means ofthese parameters. The result showed that the solid filler Mg treated by functionaladditives have better interfacial properties.Reaction mechanism of Mg, AP with kinds of different functional additives has beenanalyzed, which is useful to explain action of the functional additives and affection tointerfacial adhesive properties. The solubility parameter of Mg, functional additives and matrix has been estimated. According to interfacial diffusion theory, we havepredicted the interfacial compatibility between the modified filler and matrix will bebetter.Finally, according to the test of application performance such as the apparentviscosity of the slurry and the tensile strength, elongation at break of the grain, theestimated conclusions were verified. The results showed that the apparent viscosity ofthe slurry declined and the tensile strength of the grain increased after treatment byfunctional additives, but the elongation at break of the grain decreased slightly.The conclusion showed that the functional additives can be adsorbed on the solidfiller surface to reduce the interfacial tension between the filler and the matrix andimprove the interfacial wettability. because of their high degree of functionality tocreate high crosslinking density and high modulus interlayer, the transition layer andthe Mg, AP have higher wetting work and the enthalpy of acid-base function. Bycomprehensive consideration of interfacial wetting function, interfacial acid-basefunction, interfacial bonding function, the estimation of the Compatibility and the testof the technological properties and the mechanical properties in the study， weprediction that the functional additives such as1D can improve the compatibility andinterfacial bonding situation and enhance mechanical properties of the water ramjetengine propellant.