Thermal Degradation Residue And Influence Factors Of Poly ?-methyl Styrene

Due to excellent degradation performance,Poly ?-methylstyrene(PAMS)is always used to fabricate mandrel materials in the laser inertial confinement fusion(ICF)experiments.Recently,the degradation mandrel technology has became one of the main methods for the preparation of ICF hollow capsules.The quality of ICF capsules is highly depended on the degradation performance of PAMS mandrel.However,there still exist obvious residue on the internal surface of capsules that cannot meet the strict requirements of ICF capsules.Base on this,it is very important to investigate the thermal degradation residue and its influence factors.To study the effect of polyvinyl alcohol(PAA)and polychloroprene(PVA)on PAMS microspheres residues,which is used as out water phase in the preparation of PAMS microspheres.In this paper,raw PAMS,PAMS(PAA)microspheres and PAMS(PVA)microspheres were selected to investigate the differences in degradation behaviors,and the reasons for the residues are discussed.Results show that the degradation rate of PAMS microspheres decreased between 170 to 250 ?.Compared with raw PAMS,the contents of methyl group and benzene ring decreased in PAMS(PAA)microspheres and PAMS(PVA)microspheres residues,but the residual ratio increased.Moreover,the root mean square roughness of PAMS(PVA)caupsules residues was the highest.With the increase degradation rate,the molecular weight of PAMS decreased,the molecular weight distribution and the degradation temperature increased.The degradation products,degradation temperature and isothermal degradation kinetics of PAMS were analyzed by pyrolysis gas chromatography-mass spectrometer(Py/GC-MS)and thermogravimetric analyzer(TG).Results show that molecular weight have no influence on the degradation products of PAMS.The ?-methylstyrene monomer has highly selectivity,the productivity is close to 100%.The degradation temperature of PAMS within 240-450 ?,and its increased with the decrease of molecular weight.The isothermal degradation activation energy of PAMS decreased with the increase of molecular weight,and increased with the increase of PAMS degradation ratio.The degradation residues and residual ratios of PAMS were characterized by thermal degradation furnace,electronic scales and TG.The effects of degradation condition,substrate and the mixture of molecular weight on PAMS residue were studied.Results show that PAMS(PAA)microspheres was more suitable to prepare ICF capsules than PAMS(PVA)microspheres,due to smaller residue.By increasing the degradation temperature,holding time,gas flow rate,and adding PAMS with high molecular weight,the degradation residue of PAMS decreased.