Perspex methacrylate

The action of sulphuric acid alone upon acetone cyanohydrin affords a-methylacrylic acid. The methyl methacrylate polymers are the nearest approach to an organic glass so far developed, and are marketed as Perspex (sheet or rod) or Dialcon (powder) in Great Britain and as Plexiglass and Luciie in the U.S.A. They are readily depolymerised to the monomers upon distillation. The constitution of methyl methacrylate polymer has been given as ... 

Place 25 g. of methyl methacrylate polymer (G.B. Diakon (powder). Perspex (sheet) U.S.A. Lucite, Plexiglass) in a 100 ml. Claisen flask, attach an efficient condenser e.g., of the double smface type) and distil with a small luminous flame move the flame to and fro around the sides of the flask. At about 300° the polymer softens and undergoes rapid depolymerisation to the monomer, methyl methacrylate, which distils over into the receiver. Continue the distillation until only a small black residue (3-4 g.) remains. Redistil the hquid it passes over at 100-110°, mainly at 100-102°. The yield of methyl methacrylate (monomer) is 20 g. If the monomer is to be kept for any period, add 0 -1 g. of hydro quinone to act as a stabiUser or inhibitor of polymerisation. 

During this period, the ICI laboratories were also making their other great contribution to the range of plastics materials—the product which they marketed as Perspex, poly(methyl methacrylate). As a result of work by two of their chemists, R. Hill and J. W. C. Crawford, it was found that a rigid transparent thermoplastics material could be produced at a commercially feasible cost. The material became invaluable during World War II for aircraft glazing and to a lesser extent in the manufacture of dentures. Today poly(methyl methacrylate) is... 

Examples of commercial poly(methyl methacrylate) sheet are Perspex (ICI), Oroglas and Plexiglas (Atoglas). Poly(methyl methacrylate) moulding powders include Diakon (ICI), Acry-ace (Fudow Chemical Co., Japan), Lucite (Du Pont) and Vedril (Montecatini). 

Various polymeric materials were tested statically with both gaseous and liquefied mixtures of fluorine and oxygen containing from 50 to 100% of the former. The materials which burned or reacted violently were phenol-formaldehyde resins (Bakelite) polyacrylonitrile-butadiene (Buna N) polyamides (Nylon) polychloroprene (Neoprene) polyethylene polytriflu-oropropylmethylsiloxane (LS63) polyvinyl chloride-vinyl acetate (Tygan) polyvinylidene fluoride-hexafluoropropylene (Viton) polyurethane foam. Under dynamic conditions of flow and pressure, the more resistant materials which binned were chlorinated polyethylenes, polymethyl methacrylate (Perspex) polytetraflu-oroethylene (Teflon). 

Poly (methyl methacrylate) has excellent optical properties and is marketed under the names Lucite, Plexiglas, and Perspex. 

Acrylic resins (Perspex, PMMA, Paraloid) -1930 Varnishes, adhesives, glazing, sculptures, paint media Sensitivity to sunlight. Methacrylates are subjected to bond cleavage. Acrylates undergo cross linking reactions... 

Reppe carried out researches in Germany and his work enabled large scale production of vinylpolymers from acetylene. In late thirties polystyrene and polymethacrylate were produced on large scale in Germany. ICI in England manufactured polymethyl methacrylate (Perspex) in 1936. 

Theses polymers are made from acrylic acid, its homologues and their derivatives. Glass like resins were made from esters of aerylic acid in 1877 by Fitting and Peter by Kahlbaum. In 1928, Rohm and Hass, a German Company started commercial development of methacrylic esters. Limited production started in 1933. The rapidly expanding air-force used this plastic in place of glass in the aeroplanes. Most of the early production of "Plexiglass was used up by air-force planes. In 1936, ICI marketed methyl methacrylate sheets as "Perspex". 

The first ester, methyl methacrylate is a bulk chemical. It is the monomer whose polymerization (Chapter 52) gives Perspex, the rigid transparent plastic used In windows and roofs. The second ester is an important local anaesthetic used for... 

The polymer of methyl methacrylate (MMA) is known as Perspex. It is a clear transparent glasslike material with high hardness, resistance to fracture, and chemical stability. The conventional route, as shown by reaction 4.10, involves the reaction between acetone and hydrocyanic acid, followed by sequential hydrolysis, dehydration, and esterification. This process generates large quantities of solid wastes. An alternative route based on a homogeneous palladium catalyst has recently been developed by Shell. In this process a palladium complex catalyzes the reaction between propyne (methyl acetylene), methanol, and carbon monoxide. This is shown by reaction 4.11. The desired product is formed with a regioselectivity that could be as high as 99.95%. 

The imaging performance of the CW-NMRI system can be demonstrated by showing 2- and 3-D images of a rigid polymer such as poly (methyl methacrylate) (PMMA) (Perspex/Plexiglas). Spectroscopic investigations carried out on this... 

Methyl methacrylate (MMA) is an important commodity since it is polymerized to give poly methylmethacrylate (PMMA), a strong, durable and transparent polymer sold under the trade-names Perspex and Plexiglas. Since the conventional routes to MMA involve either the reaction of acetone with HCN to give the cyanohydrin (which has environmental problems), or the oxidation of isobutene, alternative carbonylation routes to MMA are being developed. One of these is the Lucite Alpha process which is claimed to decrease production costs by ca. 40%. This first synthesizes methyl propionate by a methoxycarbonylation of ethylene (Equation 23), using a palladium catalyst with very high (99.8%) selectivity. In the second step, MMA is formed in 95% selectivity by the reaction of methyl propionate with formaldehyde (Equation 24). 

Perspex [or poly(methyl methacrylate)] (Figure 6.2.20) is also made by polymerisation of a similar starting material, methyl 2-methylpropenoate (methyl methacrylate). 

Of the methacrylics, methyl methacrylate (MMA) is by far the most important intermediate, with a production of approx. 2 X 10 t/a (1.6 X 10 t/a for Europe and USA [la]). It finds its main application in polymers as Plexiglass or Perspex, a crystal-clear artificial glass with high hardness, resistance to fracture, and chemical stability. About 80 % of the MMA is produced on the basis of the Acetone-Cyano//ydrin (ACH) process [lb]. This process involves stoichiometric chemistry and is characterized by an overall yield of MMA of about 80 % (based on acetone) with the stoichiometric production of about 2.4 t of ammonium bisul-fate/sulfuric acid waste per ton of MMA. This process is therefore faced with increasing environmental costs. As a consequence, several alternative catalytic processes for MMA production are - and have been - under development. 

Finally, the diversity of the bulk properties of proteins is unequaled in any other known polymer class. Proteins form materials as diverse as the hard substance of nails and hair, the transparent substance of the lens, the elastic substance of collagen, and so on. Some of tliese properties are equaled by polymers in other classes keratin by the carbohydrate polymer chitin (A-acyl-o-glucosamine), the transparency of the lens proteins by the polymer Perspex (polymethyl methacrylate), the toughness and elasticity of collagen by the polyamide nylon. But no single polymer class has demonstrated such a variety of diverse bulk properties. The compaction of so many diverse bulk properties into one polymer class, polypeptides composed of the twenty proteinaceous amino acids, obviously contributes greatly to their biological fitness. 

Poly(methyl methacrylate) Aircraft windows, glazing, fighting Plexiglas, Perspex... 

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