Plastics. Also polymethyl methacrylate

The most important acrylic plastic is polymethyl methacrylate (PMMA). It also was the first acrylic to be produced commercially. It is an amorphous thermoplastic polymer that can be thermoformed, molded, or extruded above 150°C. It is soluble in ketones, esters, and chlorinated hydrocarbons, but is resistant to attack by dilute acids and bases. Compared to polymethyl acrylate, PMMA is more stable to exterior aging, has lower moisture absorption, and is more resistant to alkalies. 

Exchange between product and pack can occur in both directions, e.g. certain labelling materials such as heat sensitive and self-adhesive labels when in contact with plastic materials. Both the plastic and the adhesives may contain plasticisers or migratory constituents. Most cellulosics use phthalate, sebacate, phosphate-type plasticisers (e.g. methyl phthalate (DMP) may be used in cellulose acetate). Plasticisers may also be found in poly vinyl chloride/acetate copolymers, polyvinyl acetate and polyvinyl alcohol formulations, polymethyl methacrylate, nylon and certain thermosetting resins. 

Acetone a-so- ton [Gr Azeton, fr. L acetum] (1839) (dimethyl ketone, 2-propanone) n. CH3COCH3. The simplest and most important member of the ketone family of solvents. All the cellulosics plastics and polyvinyl chloride, polyvinyl acetate, polymethyl methacrylate, epoxies, and some thermosetting resins are soluble in acetone. It is also an intermediate in the production of bisphenol. It is a typical low-boiling ketone. It is a liquid which flashes at ordinary room temperature, has a bp of 57.5°C, fp of-15°C and a Sp gr of 0.788 at 25°C. Ash M, Ash I (1996) Handbook of paint and coating raw materials trade name products - Chemical products dictionary with trade name cross-references. Ashgate Publishing Ltd., New York Weast RC Handbook of chemistry and physics. The Chemical Rubber Co., Boca Roton, FL. 

Chlorinated paraffin (chlorocosane) n. Any of a family of yellow to light amber liquids produced by chlorinating a paraffin oil, with uses as secondary plasticizers for vinyls, polystyrene, polymethyl methacrylate, and coumarone-indene resins. Chlorinated paraffins also impart flame resistance to polyolefins, polystyrene, PVC, natural rubber, and unsaturated polyester resins. 

Dicapryl adipate n. C4H8(COOC8Hi7)2. A plasticizer for cellulosic and vinyl resins, yielding good low-temperature flexibility. Also compatible with polymethyl methacrylate and polystyrene. 

Diisodecyl-4,5-epoxy-tetrahydrophthalate n. A plasticizer for PVC that also acts as a stabilizer and fungistat. It is compatible with cellulose nitrate, ethyl cellulose, polymethyl methacrylate, polystyrene, and other vinyls polymers and copolymers. 

Thermoplastic castings can also be made by working with the liquid monomers. Vinyl polymers, primarily the acryhc resins such as polymethyl methacrylate, are cast by preparing a syrup of monomer and polymer and polymerizing the monomer in the mold. Sheets, rods, and tubes are prepared in this way. Cellulose acetate butyrate and mixtures of ethyl cellulose and wax are cast by plasticizing the resins to the point where they flow freely when hot but solidify on cooling. 

Plastics generally increase in strength and become more rigid at low temperature. However, many plastics will become brittle. Brittleness results when a material loses its yield. Brittleness can result from crystallization, although many linear polymers become brittle without crystallizing. Rubber-type materials exhibit brittle behavior similar to that of thermoplastics. It also should be noted that some plastics have useful properties below their brittle points (e.g., polystyrene and polymethyl methacrylate). 

Polymethyl methacrylate (PMMA), also called Plexiglas, Lucite, or Perspex, is a colorless clear transparent plastic with excellent outdoor stability if UV absorbers are added to the polymer— otherwise, it yellows on exposure to sunlight. Like styrene, it also unzips on heating to reform the monomer. It has poor scratch resistance but was the plastic of choice for early contact lenses. 

Butyl Ethylhexyl Phthalate n (butyl octyl phthalate, BOP) A mixed ester of butanol and 2-ethylhexanol, widely used as a primary plasticizer for PVC compounds and plastisols, in which it performs like dioctyl phthalate in most respects. It is also compatible with vinyl chloride-acetate copolymers, cellulose nitrate, ethyl cellulose, polystyrene, chlorinated rubber, and at lower concentrations, with polymethyl methacrylate. 

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