Methacrylate esters, PMMA

Scheme 8.12 Preparation of the diblock copolymer 57 by random copolymerization of PMMA block prepared by ATRP, methacrylic esters containing alkoxyamine nnits 55 and 56 [44],...

One attractive possibility is the use of the a-keto-oxime chromophore. It has a strong absorption at 220 nm whose tail, which extends to 240-250 nm, would improve the absorption characteristics of PMMA. Also, the esters possess a N-O bond which is photochemically labile yet sufficiently thermally stable so as to be compatible with the various processing steps. The solution degradation of a-keto oximino methacrylate esters upon irradiation with light of X365 nm has been reported by Delz-enne (2), and we proceeded to investigate the solid state photodegradation of similar copolymers and their possible utility as deep UV photoresists. 

Poly(acrylates) and poly(methacrylates) form another class of common polymers with saturated carbon chain backbone. Polyacrylates can be considered vinyl polymers with the -COOR group attached at every other carbon atom in the chain. However, due to their common use and particular properties, polyacrylates form a separate polymer class together with polymethacrylates. Among the most common polymers from this class are those obtained from acrylic acid methyl ester (PMA) and methylacrylic (methacrylic) acid methyl ester (PMMA). Acrylic polymers have many practical applications in automotive industry, in the production of medical materials, paints, coatings and lacquers, adhesives, textiles, and synthetic leather. Poly(methacrylic acid methyl ester) can be obtained in cast sheets with applications in technical components, furniture, building materials, etc. Formulas for poly(acrylic acid), two polyacrylates, and poly(methyl methacrylate) are shown below ... 

Poly(acrylic acid) Poly(methyl acrylate), PMA Poly(acrylic acid n-butyl ester) Poly(methacrylic acid methyl ester), PMMA... 

If an analogy with methacrylate is valid, one expects the n-butyl ester of itaconic acid to be less sensitive than the methyl ester. Reported values for poly(n-butyl methacrylate) are about half those for PMMA (9). In the present work, PDnBI indeed shows little advantage over PMMA (Figure 3). The ratio of G(s) for the n-butyl ester of itaconic acid to that for the methyl ester was found to be approximately the same as the ratio reported for the corresponding methacrylate esters. 

Methacrylate Esters. Figure 1 shows typical hole profiles of TPP/PMMA during the temperature cycle experiment and a schematic diagram of the temperature cycling. At first a hole is burned and measured on the profile at 20 K. Then the temperature d die sample is elevated to a certain excursion temperature. The sample is kept at the excursion temperature for 5 min. Then we cool the sample again to 20 K and measure die hole profile. We repeat the temperature cycle with increasing elevated temperature. 

The polymer investigated here is a polymethylmethacrylate (PMMA) copolymerised with methacrylate esters of a dicyanovinyl-terminated bisazo dye derivative. A nitro-terminated version of the bisazo dye derivative and a typical monoazo dye. Disperse Red 1 (DRl), derivative is also discussed in [47]. These azo dyes are hereafter referred as 3RDCVXY, 3RNO2, and 2RNO2, respectively. The molecular structure of 3RDCVXY is shown in Figure 3.12a. 

Commercial acrylic resins comprise a broad array of polymers and copolymers derived from esters of acrylic acid and methacrylic acid. They range from the homopolymer of methyl methacrylate to a variety of copolymers including both the thermoplastic and thermoset type and ranging from hard and stiff types to soft and elastomeric types. The most common of the thermoplastic acrylic resins are the poly(methyl methacrylate) homopolymer (PMMA) and the copolymers containing predominantly methyl methacrylate but with small amounts of methyl or ethyl acrylate, acrylonitrile, or styrene comonomers added for improved toughness. 

Lucite lii- Slt Poly(methyl methacrylate). DuPont s trade name for methacrylate-ester monomers and polymers (acrylic), including PMMA and several other resins, and for certain products made from such resins. 

Chemical Properties. The chemical-resistance properties of methacrylic ester polymers are even higher than those of the acrylic esters. Methacrylic esters imdergo a lower degree of hydrolysis in either acidic or alkaline media than acrylics. Both acrylics and methacrylics easily outperform vinyl acetate-containing polymers which are well known to be susceptible to hydrolysis of the side-chain ester. There are marked differences in the chemical-resistance properties of different forms of PMMA. The syndiotactic (alternating) form of PMMA is the most chemically inert. The rate of hydrolysis for syndiotactic PMMA is lower than that for isotactic (26) radical polymerizations generate large portions of syndiotactic PMMA and benefit in terms of stability. 

PMMA. See Methacrylic Ester Polymers. POLYACETAL. See Acetal Resins. POLYACRYLAMIDE. See Acrylamide Polymers. 

Methyl methacrylate (MMA) is by far the most important methacrylic ester monomer, accounting for 90% of the volume of methacrylic ester monomers. Polyfmethyl methacrylate) (PMMA) was first synthesized in 1928 in various laboratories, and was first brought to market in 1933 by Rohm Haas Co. under the trademark Plexiglas. ICI then reformed Rohm s method and commercialized MMA in 1937 by the acetone cyanohydrine (ACH) process,[l] which is still the most widely adopted technique even today. The world production capacity of PMMA has almost doubled in the past fifteen years, and overall global PMMA production capacity accounts for six hundred and fifty thousand tons per year. [3] It is predicted that starting from 2010, the demand for PMMA will rise by 3-5% annually and the demand of MMA is expected to steadily grow in the future.[3]... 

Copolymerization with other vinyl monomers, such as St and VAc, allows for further modification of acrylic and methacrylic esters. The ease of structural modification to produce desired blend properties (miscibility) is well-documented in the experimental literature. The common methacrylate polymer is PMMA and has been noted to be miscible with various other polymers such as PVC and PEO. 

The first attempts to synthesize poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) were the hydrolysis of poly(acid derivatives) such as esters, acylchlorides, nitriles, or amides. The hydrolysis has to be quantitative otherwise, one obtains a copolymer of acid and derivative [472]. On the other hand, hydrolysis in boiling alkaline solution can diminish the molar masses [473]. One possibility is to polymerize methyl methacrylic ester and to hydrolyze the resulting PMMA in acetic acid by the addition of a small amount of -toluenesulfonic acid as a catalyst. The solution is kept at 120 °C for 18 h and the methylacetate fonned is removed by distillation [474]. The degree of hydrolysis depends strongly on the tacticity of the original polymer. Syndiotactic PMMA is hydrolyzed slowly, but isotactic polymer is hydrolyzed very rapidly [475]. The polymers examined had molar masses up to 125,000. 

Monomer sequence is also important when methacrylic esters or acrylonitrile are involved. It is well known that homopolymerization of MMA failed to be controlled by common nitroxides, which closes the route to PMMA macroinitiators. In contrast, controlled polyacrylonitrile (PAN) homopolymers can be obtained under SGI control but chain extension leads to bimodal molar mass distributions, even with... 

Although several other methacrylate ester polymers resemble PMMA in degrading thermally to give 100% monomer, this behaviour is by no means general for this class of polymers and some polymethacrylates, in contrast, give very little monomer. 

Unlike most crystalline polymers, PVDF exhibits thermodynamic compatibiUty with other polymers (133). Blends of PVDF and poly(methyl methacrylate) (PMMA) are compatible over a wide range of blend composition (134,135). SoHd-state nmr studies showed that isotactic PMMA is more miscible with PVDF than atactic and syndiotactic PMMA (136). MiscibiUty of PVDF and poly(alkyl acrylates) depends on a specific interaction between PVDF and oxygen within the acrylate and the effect of this interaction is diminished as the hydrocarbon content of the ester is increased (137). Strong dipolar interactions are important to achieve miscibility with poly(vinyhdene fluoride) (138). PVDF blends are the object of many papers and patents specific blends of PVDF and acryflc copolymers have seen large commercial use. 

Although the potassium superoxide route can be universally applied to various alkyl methacrylates, it is experimentally more difficult than simple acid hydrolysis. In addition, limited yields do not permit well-defined hydrophobic-hydrophilic blocks. On the other hand, acid catalyzed hydrolysis is limited to only a few esters such as TBMA, but yields of carboxylate are quantitative. Hydrolysis attempts of poly(methyl methacrylate) (PMMA) and poly(isopropyl methacrylate) (PIPMA) do not yield an observable amount of conversion to the carboxylic acid under the established conditions for poly(t-butyl methacrylate) (PTBMA). This allows for selective hydrolysis of all-acrylic block copolymers. 

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