ALTERNATIVE PROCEDURES FOR THE RECYCLING OF SHEET MOLDING COMPOUNDS

To establish the parameters for converting sheet molding compounds (SM Cs) to useful products, various technical approaches, viz., solvent ex traction, hydrolysis, and pyrolysis, have been explored. Thermogravime tric analysis of an SMC sample indicated that it contains about 25% by weight organics and 75% inorganics, mainly glass fibers and CaCO3 as filler. Solvent extraction of ground SMC with acetone, methylene chlor ide, chloroform, or chloroform: benzene (1:1 vol) yielded low quantiti es of a gummy, viscous extract. Hydrolysis of the extracted SMC sample under strong alkaline conditions was also studied. A unit structure w as postulated for the hydrolysate based upon elemental and molecular w eight analysis. Pyrolysis of both extracted and unextracted SMCs in ni trogen at 500-degrees-C and in air at 400-degrees-C yielded organic oi ls. These oils were characterized for their calorific values. The prod ucts of pyrolysis consisted of mainly aromatics along with some oligom ers. The extract and the oil from pyrolysis appear to be compatible wi th epoxy systems. Their use as an extender for epoxy systems, while th at of the inorganic residue (glass fibers and CaCO3) as a filler for e poxy system, have been explored.