Study On The Preparation Of POSS/C₆₀ Composite Films And Modification Of PMMA

Polyhedral oligomeric silsesquioxane （POSS） has a good toughness andtranslucency of the organic material and is easy to process. It also has excellentstable performance characteristics and mechanical properties of inorganic materialsand so is widely used in aerospace fields. With a characteristic of theelectron-deficient shown by the delocalized big π bond in the three-dimensionalspace, fullerene (C₆₀) has outstanding optical and electrical properties. Polymethylmethacrylate （PMMA, commonly known as organic glass） has an excellenttranslucency and mechanical properties. However, the low glass temperature willlead to easy charge accumulation under the condition of high temperature. Thereforeits application is extremely limited.In this paper, we adopt the sol-gel method which includs: under the catalysis ofthe dilute solution of formic acid, use the silane coupling agent to prepare the POSSsol system of epoxy and aminopropyl which contains R group; use phase transferoxidation method to modify the surface of C₆₀and graft many hydroxy on it; useradical polymerization method to prepare the PMMA which has stable performance;use FTIR testing methods to characterize the changes of the chemical substancesand functional groups before and after the response of each system.Prepare the hybrid system of POSS/C₆₀and scattered it into the PMMA, bymaking C₆₀（OH）_ngroup and–R group bond with POSS50of aminopropyl andPOSS60of epoxy respectively through electrophilic substitution, epoxyring-opening and addition reaction. Use FTIR to identify that POSS and C₆₀（OH）_nare bonded in a chemical bond way rather than in a simple physical dispersion way;SEM photos indicate that the hybrid system of C₆₀（OH）_n/POSS can form an uniformand continuous material, and POSS/C₆₀（OH）_nmodified PMMA without significantphase separation phenomenon and the film surface is uniform.In this paper, we carry on a systematic research about the hybrid system ofPOSS/C₆₀（OH）_nmodifying the antistatic properties, thermal stability, mechanicalproperties and optical properties of PMMA. Experimental results shows: through10%of the C₆₀ doped with1.5%of the POSS, the surface resistance of thecomposite membrane of PMMA can decrease from1015Ω/m2to108Ω/m2and theglass temperature of PMMA can increase from75℃to more than300℃; thehardness of the composite membrane can reach2.13GPa and the bonding strengthwith the matrix is more than0.49mN; the friction coefficient of the materialsurface is about0.14and the modulus is0.64GPa and so make it have a good self-cleaning properties; the hybrid system of POSS/C₆₀（OH）_ndoped in the casethat the absorption of visible light of PMMM is not affected, gives its goodultraviolet absorption performance and make it widely used in the field ofresistance of laser attack.