Curing times, methyl methacrylate

Figure 1. Curing times of methyl methacrylate containing fixed initial concentrations (in mol/L) of benzoyl peroxide arid aryl-substituted N,N-dimethylaniline versus the value of the aryl substituent of the amine. (Curing times from Ref. 5

The polymers are used as molding resins for optical articles, since the transparency roughly corresponds to that of poly(methyl methacrylate), but the resistance to scratching and abrasion is about 30-40 times better than in PMMA. Poly(diethylene glycol bisallyl carbonate) is used, for example, for the lenses of sunglasses. Since the cured resins have an electrical conductivity which is somewhere between those of porcelain and poly(tetrafluoroethylene), they are used for electrical insulation. Prepolymer-soaked resin mats are obtainable commercially as prepregs. 

For a long time, denture base systems relied completely on the use of metallic materials. The first non-metalUc denture base material. Vulcanite, was introduced in the 1850s, and served as a denture base system for almost 100 years, when it was then replaced by poly(methyl methaaylate) (PMMA). Although PMMA was first developed in 1931 [93], the first commercially available product was not manufactured until 1935. PMMA for denture base resins is usually maiketed as pre-polymerized beads of 35-200 p,m in diameter, and cured via emulsion polymerization, whereby the methyl methacrylate (MMA) monomer, supplied as a liquid, is mixed with powder forming a dough upon initiation of curing, which will proceed via addition polymerization as reinforcements, small proportions of other alkyl methacrylates (ethyl or butyl) may be added to copolymerize with MMA. Other modifications to... 

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