The Muscovite Fill Methacrylate Butyl Covering Materials Preparation And Application

A new kind of inhibitor layer—PBMA was studied in this paper. After a series ofimprovement on PBMA's synthesis process and coating process, it had been successfullyapplied to propellant.At first, the polymerization characteristic of BMA was discussed in the paper, bycontrast with MMA, using the instrument dilatometer. It was confirmed that thepolymerizing activity of BMA was lower than MMA, and its polymerizing condition wasstricter.Three kind of silane coupling agents were used to modify the surface of muscovite,and the coupling agent—KH-550 was proved as the best. By the design of orthogonalexperiments, the optimal process was found. The condition was: grain diameter—500 MU,coupling agent dosage—1%, reaction temperature—120℃. Some analytical means wereused to test the properties of modified muscovite, and the result showed that the muscovitewas separated well in the resin PBMA.In order to prepare the eligible inhibitor layer, the effect law of synthesis process onPBMA's properties was studied. The best technique was found by testing the gel time, themechanical performance and thermal performance. The dosage of cross-linking agent was0.2%, the filling amount of muscovite was 10%, and the initiator amount was 0.7%.The application of PBMA material to propellant was emphatically studied in the paper.By means of filling with muscovite, setting transition-layer between the interfaces, andpretreating the propellant, many problems had been overcome, such as poor heat-resistance,low peeling strength, and the migration of nitroglycerine. By doing the peeling test,scanning electron microscopy (SEM) analysis, infrared spectrometry (FT-IR) analysis,compatibility test, and oxygen index determination, the combined property of PBMA hadreached the intemal advanced level. The main performances were as follows.(1) Under normal temperature, tensile strength≥12.15MPa, breaking elongation rate≥261%, shore hardness H_A＞92, peeling strength＞2.15 N/mm.(2) PBMA's compatibility with the propellant had reached the second class.(3) The operable time was over 50 minutes; the solidifying temperature was 55℃;and the filler—muscovite wasn't stratified at all in the resin system.