The Design And Synthesis Of Neutral Polymeric Bonding Agent

In the early 1980s,the nitrate ester plasticized polyether propellant which has played nitrate liquid plasticizer energy characteristics and polyether-based polyurethane adhesive low temperature mechanical properties,was a class propellant which had energy density excellent characteristics and low-temperature mechanical properties . And it also contained a large number of solid components Octogen(HMX).It represented the developing direction of current high-energy solid rocket propellant.However,such kind of propellants could easily arise "dewetting" in the process of using and the mechanical properties could not meet the request.The neutral polymer bonding agents (NPBA) invented by C.S.Kim could significantly improved the propellant mechanical properties.However,with the development of NEPE propellant,the Kim's design and synthesis methods of bonding agents was deficient.The purpose of this study was improved the design methods of NPBA,explored water dispersion polymerization that was environmental safety and predicted interface bonding properties.By analyzing the design method of Kim,we found that the NPBA solubility parameter criterion were derived by handling the solid propellant mixed plastic which dissolved NPBA to polymer concentration solution , and Hildebrand solubility parameters was used to calculate the enthalpy-change of mixing.But the volume of NPBA in premixed slurry was only 0.1% to 1.0%,the concentration range was in dilute solution.And using dilute polymer solution theory to deal with the problem would be more appropriate.In this dilute polymer solution and the solubility parameter of the theory polar fraction concept were introduced,the new NPBA solubility parameter criterion were proposed.This Criterion put together NPBA solubility parameters, molecular weight , the amount and phase separation critical temperature modernity.And a reasonable explanation was gived for the physical meaning of the experience value.The aqueous dispersion copolymerization of NPBA was studied.NPBA which the composition and molecular weight were controllable , were synthesized . Acrylonitrile(AN) andβ-hydroxyethyl acrylate(HEA) was used as comonomers . Various factors influencing the copolymerization were investigated.Viscosity-average molecular weight of the products were measured by Ubbelohde viscometer , hydroxyl content was titrated by acetylation method ,compostion of copolymers were analyzed by elemental analysis(EA) and the structure was characterized by IR . The result showed that the best condition of the copolymerization:the quality of AN,HEA,polyvinyl alcohol,β–mercaptoethanol,potassium persulfate and water were 8g,2g,0.1g,0.847g,0.45g,100g;reaction temperature at 60°C;reaction time was 2h.The yield of NPBA was 82.0%,viscosity-average molecular weight was 5200 and hydroxyl content was 2.08mmol﹒g^-1.By measuring the contact angle of NPBA with the reference fluid,the surface tension and polar fraction has been calculated.The work of adhesion between NPBA and HMX has been estimated.It was observed the hydroxyl content of NPBA correlate well with polar fraction.Research showed that the adhesion work between NPBA and HMX was about 90.0mN.m^-1,and increased with the polar fraction,but increment was small.NPBA hydroxyl content increased with the polar fraction.