Plastic glazing sheets

To minimise the risk of stress cracking, flat sheets of plastic glazing material should be installed completely flat, i.e., they should not be forced to take up curvature by the use of mechanical fastenings. 

The chemistry of polycarbonates is similar to the chemical behavior of polyesters. We can think of a carbonate as being a diester of carbonic acid, H2CO3, which is unstable itself. Polycarbonate is a strong, clear plastic used in automobiles (25%), glazing and sheet (20%), optical media (15%), appliances (8%), computers (7%), medical industry (7%), and recreation and... 

The cellulose nitrate plastics were adaptable, easy to work, and quite durable, but had the disadvantages of being plasticized with camphor and flammability (they burnt, in fact, quite violently). At one time the smell of camphor was thought pleasant (even therapeutic) but instances have been cited of harm to children attributed to inhaling this vapour. So, while the acetates were not quite so attractive in terms of ease of fabrication it was inevitable eventually that the so-called safety plastic would supersede its forerunner. Among other uses it was stitched into motor car tonneau covers as flexible glazing, and thicker transparent sheet was cut and formed into cockpit canopies for aircraft [though by that time the material preferred for this purpose was poly(methyl methacrylate)]. Later on, in their turn, sheets made from cellulose acetate butyrate and propionate took over some of the uses of earlier commercial materials. 

The floor of the storage site should be made of sealed cement, glazed ceramic tile, no-wax sheet flooring, or another easily cleaned material. Carpeting, wood, soil, and other absorbent floors are difficnlt or impossible to decontaminate in case of a leak or spill. For ease of cleannp, shelving and pallets should be made of nonabsorbent materials snch as plastic or metal. If wood or fiberboard materials are nsed, they should be coated or covered with plastic or polyurethane or epoxy paint. 

Margard sheet [GE Plastics] Extraded polycarbonate glazing grade sheet uv stabilized, coated on both faces with mar-resistant silicone coating. 

Chem. Descrip. 2-Hydroxy-4-methoxybenzophenone CAS 131-57-7 EINECS/ELINCS 205-031-5 Uses Lt. stabilizer, UV absorber for plastics and coatings (esp. for flexible and rigid PVC, unsat. polyesters, and acrylics), outdoor sheeting and glazing applies., molded products, adhesives in acrylic plastics for food pkg. 

Uses Solvent for candy glazes, plastics, resins, cellulose plastics, photographic film, transparent sheeting, industrial collodions and collodion USP, inks, sterilizing/preserving sol ns. process solvent for pectin, food prods., vitamins, hormones, yeasts, antibiotics, vaccines, medicinal chems. incl. alkaloids. 

The plastic resin is often used for safety glasses, scratch-resistant glazing, lens covers, etc. It is manufactured as a cast sheet by PPG. The allyl diglycol carbonate monomer is available commercially from Polymer Products. 

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