Plastics, acrylic

This family includes a range of polyacrylates (III), polymethacrylates (IV) and the important fibre-forming polymer, polyacrylonitrile (V). 

Methyl, ethyl and allyl acrylate were first prepared in 1873 by Caspary and Tollens, and of these materials the last was observed to polymerise. In 1880 Kahlbaum reported the polymerisation of methyl acrylate and at approximately the same time Fittig found that methacrylic acid and some of its derivatives readily polymerised. 

In 1901 Otto Rohm reported on his studies of acrylic polymers for his doctoral dissertation. His interest in these materials, however, did not cease at this stage and eventually in 1927 the Rohm and Hass concern at Darmstadt, Germany commenced limited production of poly(methyl acrylate) under the trade names 

Acryloid and Plexigum. These were soft gummy products of interest as surface coatings rather than as mouldable plastics materials. About 1930 R. Hill in England and W. Bauer in Germany independently prepared poly(methyl methacrylate) and found it to be a rigid, transparent polymer, potentially useful as an aircraft glazing material.  

The first methacrylic esters were prepared by dehydration of hydroxyisobutyric esters, prohibitively expensive starting points for commercial synthesis. In 1932 J. W. C. Crawford discovered a new route to the monomer using cheap and readily available chemicals—acetone, hydrocyanic acid, methanol and sulphuric acid— and it is his process which has been used, with minor modifications, throughout the world. Sheet poly(methyl methacrylate) became prominent during World War II for aircraft glazing, a use predicted by Hill in his early patents, and since then has found other applications in many fields. 

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Acrylic Plastics 1931 G P P F-P F-P Injection, compression, extrusion or blow molded Lenses, aircraft and building glazing, lighting fixtures, coatings, textile fibers... 

Acrylic plastics Group of plastics based on resins generated from the polymerization of acrylic monomers (e.g., ethyl acrylate and methyl methacrylate). 

Both processes rely on a fast flow system and the rapid quenching of product gases yields of up to 90% can be attained. It is salutory to note that US production of this highly toxic compound is 600000 tonnes pa (1992) and world production exceeds one million tonnes pa. Of this, 41% is used to manufacture adiponitrile for nylon and 28% for acrylic plastics ... 

The ophthalmic applications for plastics lenses include contact lenses which are now made of acrylic plastics. Another material for this application is a special hydrophillic acrylic polymer used in soft contact lenses. These lenses are much more comfortable than rigid contact lenses. 

This photoelastic stress analysis is a technique for the nondestructive determination of stress and strain components at any point in a stressed product by viewing a transparent plastic product. If not transparent, a plastic coating is used such as certain epoxy, polycarbonate, or acrylic plastics. This test method measures residual strains using an automated electro-optical system. 

Methacrylates and acrylates are a large group of polymers that together form acrylic plastics used in many common household products. 

Two catalyst layer disks were punched from an E-Tek ELAT sheet. The sheet was placed on clean acrylic plastic and the disks were punched with a 3.8 centimeter (1.5 inch) arch punch and the mechanics hammer. 

Note that glazing is acrylic plastic to comply with the AMC Safety Manual requirements. Screws for attachment of wood door frames and vision panel stops are countersunk and caulked. Joints not taped are sealed with caulking. It should be noted here that Sunflower AAP has had major problems with exterior wood doors exposed to the weather. A recurring problem has been the delamination of wood door materials. This may require a change to a more weather-resistant door material such as fiberglass reinforced plastic. Details for doors of this material are included in the standard architectural details. 

Polycarbonate is a thermoplastic and is often marketed under trade-names such as Lexan or Tuffak. It should not be confused with acrylic plastics, marketed under tradenames such as Plexiglas or Lucite, which are flammable and exhibit a brittle failure mode. 

Power Law Contact Distributions and Contact Stresses in Quartz, Calcite, Glass and Acrylic Plastic. 

The most widely used acrylic plastics are PMMA (Lucite) or copolymers of methyl methacrylate with small amounts (2 to 18%) of methyl or ethyl acrylate (Plexiglas). These commercial products, which are available as sheets and as molding powders, have a specific gravity of about 1.2, a heat deflection temperature of about 95 C, a refractive index of about 1.5, and a water absorption of 0.2%. PMMA is more resistant to impact than PS or glass, but its scratch resistance is inferior to that of glass,... 

See also Acrylic Plastics Elastomers Fiber-Reinforced Compos ites Polyester Fibers and Polymers. 

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