Abstract: There are provided fiber glass reinforced resin compositions comprising an acrylic copolymer consisting mainly of methyl methacrylate, fiber glass and an inorganic or organic compound containing pentavalent phosphorus atoms, whereby a deterioration phenomenon of whitening under the influence of water over a long period of time is remarkably improved.

Abstract: A process for preparing vinyl aromatic resin-, e.g. styrene-,based resinous materials to render them brittle and disintegratable upon prolonged exposure to ultraviolet light while retaining, in the absence of ultraviolet light, substantially the same appearance, processability and mechanical properties of conventional vinyl aromatic resin-based materials, comprising copolymerizing said vinyl aromatic monomer with from 0.5 to 6.0% of a conjugated diene monomer, e.g. isoprene, based on the total weight of the two monomers, initially copolymerizing said vinyl aromatic monomer with only a portion of the total amount of conjugated diene monomer and then completing the copolymerization with the remainder thereof, and the polymeric resin obtained by said process.

Abstract: A process for the production of glass-fiber reinforced plastics by partially copolymerizing a mixture of (A) 35-95% by weight methyl methacrylate, (B) 65-5% by weight of a vinyl aromatic hydrocarbon, and 0.2-5.0% by weight, based on the sum of (A) and (B) of a polymerizable compound containing two or more ethylenically unsaturated groups, discontinuing the partial copolymerization before gelation of said mixture has occurred, impregnating glass fibers with the resultant partially polymerized mixture and then curing the impregnated mixture.