Polyfmethyl methacrylate-methyl

Keywords Mechanical properties Plastic deformation Polyfmethyl methacrylate) Methyl methacr)date-co-N-cyclohex)d maleimide copolymer ... 

Fig. 17. Experimentally measured values of the exit concentration as a function of pressure for a polymeric solution consisting of methyl methacrylate-polyfmethyl methacrylate). Data were obtained by Werner using a twin-screw extruder. (Reproduced with permission from Werner, 1980.)...

Fig. 10 Optical micrograph showing a pre-crack in polyfmethyl methacrylate-co-N-methyl glutarimide)...

The styrene/methyl methacrylate pair contains monomers with different relative reactivity levels in Table 9-1. Polystyryl anion will initiate the polymerization of methyl methacrylate, but the anion of the latter monomer is not sufficiently nucleophilic to cross-initiate the polymerization of styrene. Thus the anionic polymerization of a mixture of the two monomers yields polyfmethyl methacrylate) while addition of methyl methacrylate to living polystyrene produces a block copolymer of the two monomers. 

Fig. 54. Monomer unit of a molecule of methyl methacrylate-styrene graft copolymer. Axis 1 parallel to the trans chain of polyfmethyl methacrylate) (i.e. the main chain of the graft copolymer the plane of which is the 1,3 plane). Axis 2 parallel to the direction of the trans chain of grafted polystyrene...

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 polyfmethyl methacrylate) is... 

The influence of solvents on the microstructure of polymer was investigated in the free radical polymerization of methyl methacrylate for the first time by Fox et al. in 196279. The stereochemical structure of the polymer prepared at 60 °C was, within the precision of the data, independent of the solvent used and did not measurably differ from that of the polymers obtained in bulk polymerization at the same temperature. Watanabe et al.80 demonstrated that the temperature dependence of the microtacticity of polyfmethyl methacrylate) varied with solvents and concluded that the temperature dependence was mainly caused by the polymer-solvent interaction. 

A further increase in steric hindrance is caused by the presence of an a-methyl group, which restricts rotation even further, thus causing Tg to increase. Typical examples are the pair polystyrene (Tg= 100°C)-poly(a-methylstyrene) (Tg=172°C) and the pair poly(methyl acrylate) (Tg=6°C)—polyfmethyl methacrylate) (Tg=105°C). 

It should be noted that the steric effects of the pendant groups considered above are simply additional contributions to the main chain effects. Similarly cis-trans isomerism in polydienes and tacticity variations in certain a-methyl substituted polymers alter chain flexibility and hence affect Tg. Well-known examples of cis-trans variations are polybutadiene cis Tg= — 108°C) and trans(T = — 18°C) or polyisoprene cis Tg = —73°C) and trans T = —53°C). An example of tacticity variation is polyfmethyl methacrylate) for which the isotactic, atactic, and syndiotactic stereostructures are associated with Tg values of 45, 105, and 115°C, respectively. 

Figure 13.6 Life cycle of polyfmethyl methacrylate) (PMMA)-containing products. MMA, Methyl methacrylate ACH, acetone cyanohydrin method TBA-DO, tertiary butyl alcohol (isobutylene) direct oxidation method TBA-DOE, tertiary butyl alcohol (isobutylene) direct oxidative esterification method C2, ethylene method TR, thermal recovery MR, material recycling. Modified from Kikuchi Y, Hirao M, Ookubo T Sasaki A. Design of recycling system for polyfmethyl methacrylate) (PMMA). Part 1 recycling scenario analysis. Int J Life Cycle Assess 20i4 i9(i) 120—9.

Figure 6.16 Schematic representation of pattern transfer by taking advantage of the self-assembly of two different diblock copolymers poly(ethylene oxide)-b-poly(st5Tene-r-4-hydroxystyrene) and poly(styrene-r-4-vinylpyridine)-b-poly(methyl methacrylate) followed by irradiation and plasma treatment. The images below correspond to square arrays of pores created onto silicon water resulting from the treatments. PS, polystyrene PMMA, polyfmethyl methacrylate) UV, ultraviolet RIE (Reactive Ion Etching).

Several other types of hydrocarboxylations and hydroesterifications have been conducted with rates and selectivity that are appropriate for the synthesis of fine chemicals and commodity chemicals. One target for hydroesterification has been methyl methacrylate, the monomer of polyfmethyl methacrylate), which is the polymer often called "acrylic". It is estimated that 2.1 million metric tons of methyl methacrylate was produced in 2005. Much of this material is produced from acetone cyanohydrin, but two alternative routes could involve catalytic carbonylation. The first route would involve the hydroesterification of methylacetylene, and this chemistry relates to the original route to methyl methacrylate by carbonylation of methylacetylene using nickel carbonyl as catalyst. The second route involves the sequence of ethylene hydoesterification, aldol addition of the resulting ester to formaldehyde, and dehydration. This sequence comprises Lucite s new "Alpha" process and is shown in Equation 17.33. The route to methyl methacrylate by hydrocarboxylation of ethylene produces water as the only byproduct. 

SCHEME 10.6 Reaction mechanism for B-H chain transfer reactions and subsequent transformations to prepare chain-end functionalized iPP and iPP-b-PMMA diblock copolymer (MMA = methyl methacrylate PMMA = polyfmethyl methacrylate)). 

The important features of rigidity and transparency make the material competitive with polystyrene, cellulose acetate and poly(methyl methacrylate) for a number of applications. In general the copolymer is cheaper than poly(methyl methacrylate) and cellulose acetate, tougher than polyfmethyl methacrylate) and polystyrene and superior in chemical and most physical properties to polystyrene and cellulose acetate. It does not have such a high transparency or such food weathering properties as poly(methyl methacrylate). As a result of these considerations the styrene-acrylonitrile copolymers have found applications for dials, knobs and covers for domestic appliances, electrical equipment and car equipment, for picnicware and housewares, and a number of other industrial and domestic applications with requirements somewhat more stringent than can be met by polystyrene. 

Problem 3.17 Calculate the solubility parameter for a methyl methacrylate-butadiene copolymer containing 25 mol % methyl methacrylate. The solubility parameter values for polyfmethyl methacrylate) (PMMA) and polybutadiene (PB) homopolymers, calculated from molar attraction constants, are, respectively, 9.3 and 8.4 (cal cm ). ... 

The thermal degradation of poly(vinyl bromide), of blends of this polymer with polyfmethyl methacrylate) and of the copolymer of vinyl bromide and methyl methacrylate have been investigated by sub-ambient thermal volatilization analysis and thermogravimetry. The results are discussed in relation to the use of the vinyl bromide unit as a Are retardant. 

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]... 

Until 2003, Chen s [28], Qu s [29-31], and Hu s [32] groups independently reported nanocomposites with polymeric matrices for the first time the. In Hsueh and Chen s work, exfoUated polyimide/LDH was prepared by in situ polymerization of a mixture of aminobenzoate-modified Mg-Al LDH and polyamic acid (polyimide precursor) in N,N-dimethylactamide [28]. In other work, Chen and Qu successfully synthesized exfoliated polyethylene-g-maleic anhydride (PE-g-MA)/LDH nanocomposites by refluxing in a nonpolar xylene solution of PE-g-MA [29,30]. Then, Li et al. prepared polyfmethyl methacrylate) (PMMA)/MgAl LDH by exfoliation/adsorption with acetone as cosolvent [32]. Since then, polymer/LDH nanocomposites have attracted extensive interest. The wide variety of polymers used for nanocomposite preparation include polyethylene (PE) [29, 30, 33 9], polystyrene (PS) [48, 50-58], poly(propylene carbonate) [59], poly(3-hydroxybutyrate) [60-62], poly(vinyl chloride) [63], syndiotactic polystyrene [64], polyurethane [65], poly[(3-hydroxybutyrate)-co-(3-hydroxyvalerate)] [66], polypropylene (PP) [48, 67-70], nylon 6 [9,71,72], ethylene vinyl acetate copolymer (EVA) [73-77], poly(L-lactide) [78], poly(ethylene terephthalate) [79, 80], poly(caprolactone) [81], poly(p-dioxanone) [82], poly(vinyl alcohol) [83], PMMA [32,47, 48, 57, 84-93], poly(2-hydroxyethyl methacrylate) [94], poly(styrene-co-methyl methacrylate) [95], polyimide [28], and epoxy [96-98]. These nanocomposites often exhibit enhanced mechanical, thermal, optical, and electrical properties and flame retardancy. Among them, the thermal properties and flame retardancy are the most interesting and will be discussed in the following sections. 

Acronyms DWNT Double-walled nanotube PVA Polyfvinyl alcohol) PTh Poly(thiophene) PAN Poly(acrylonitrile) MA Methyl acrylate PMMA Polyfmethyl methacrylate) PS Polystyrene PLA Poly DL-lactide PC Polycarbonate PCL ... 

McAlpine, M. Hudson, N.E. Liggat, J.J. Pethrick, R.A. Pugh, D. Rhoney, I. Study of the factors influencing the exfoliation of an organically modified montmo-rillonite in methyl methacrylate/polyfmethyl methacrylate) mixtures. J. Appl. Polym. Sci. 2006, 99, 2614-2626. 

FIG. 14-19. Plots of log E and log tan 5 against temperature at a frequency of 110 Hz for a two-phase blend of equal weight fractions of polyfmethyl methacrylate) and slightly cross-linked polyfbutyl acrylate). Curves calculated from modified Kemer equation for a polyfmethyl methacrylate) matrix with inclusions of polyfbutyl acrylate) containing 14.4% poly(methyl methacrylate) by volume. (Dickie and Cheung. ) Reproduced, by permission, from the Journal of Polymer Science. 

We have studied the degradation by high-energy radiation of a number of families of polymers by using a variety of techniques, including ESR spectroscopy [10,11]. In this paper we show the similarities and differences in the role of free radicals in the radiolysis of polyfmethyl methacrylate), polystyrene, and random copolymers of methyl methacrylate and styrene. 

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