PMA/PMMA

PMMA is an illicit chemical compound that is a stmctural hybrid of PMA. PMMA and PMA are almost identical compounds. PMMA may also be marketed as ecstasy tablets. In humans PMMA has no known distinction from PMA in physiological effects. For the purpose of this informational entry, PMA and PMMA will be considered alike. 

PB PBI PBMA PBO PBT(H) PBTP PC PCHMA PCTFE PDAP PDMS PE PEHD PELD PEMD PEC PEEK PEG PEI PEK PEN PEO PES PET PF PI PIB PMA PMMA PMI PMP POB POM PP PPE PPP PPPE PPQ PPS PPSU PS PSU PTFE PTMT PU PUR Poly(n.butylene) Poly(benzimidazole) Poly(n.butyl methacrylate) Poly(benzoxazole) Poly(benzthiazole) Poly(butylene glycol terephthalate) Polycarbonate Poly(cyclohexyl methacrylate) Poly(chloro-trifluoro ethylene) Poly(diallyl phthalate) Poly(dimethyl siloxane) Polyethylene High density polyethylene Low density polyethylene Medium density polyethylene Chlorinated polyethylene Poly-ether-ether ketone poly(ethylene glycol) Poly-ether-imide Poly-ether ketone Poly(ethylene-2,6-naphthalene dicarboxylate) Poly(ethylene oxide) Poly-ether sulfone Poly(ethylene terephthalate) Phenol formaldehyde resin Polyimide Polyisobutylene Poly(methyl acrylate) Poly(methyl methacrylate) Poly(methacryl imide) Poly(methylpentene) Poly(hydroxy-benzoate) Polyoxymethylene = polyacetal = polyformaldehyde Polypropylene Poly (2,6-dimethyl-l,4-phenylene ether) = Poly(phenylene oxide) Polyp araphenylene Poly(2,6-diphenyl-l,4-phenylene ether) Poly(phenyl quinoxaline) Polyphenylene sulfide, polysulfide Polyphenylene sulfone Polystyrene Polysulfone Poly(tetrafluoroethylene) Poly(tetramethylene terephthalate) Polyurethane Polyurethane rubber... 

PMA PMMA = polymer acrylic methylester (Plexiglas Lucite, Perspex) 89... 

Somewhat similar results were obtained with cellulose graft/blend systems with PMA, PMMA and poly(2-hydroxyethyl methacrylate) [Nishioka and Yoshida, 1992] and could be correlated with the degree of compatibility. In one case the thermal stability of blends containing grafted cellulose was 100°C less than those without grafted product [Nishioka et al., 1993]. 

Precipitation from solution = precipitation polymerization Monomer Initiator Polymer So in M D or So in M D in M HOPE, PP, PMMA, PS, PVC, SAN Powder In all of these polymerizafirm Important example Low-pressure methods, the polymer is polymraization of HDPEP or produced in a finely in hydrocarbon (HC) solvent distributed, heterogeneous PMA, PMMA also in HC, PS form. Viscosity remains low, in methanol, PAN in water efficient heat dissipation, and therefore rapid... 

The ionic conductivities of some copolymer electrolytes with PEO are as follows PAAM < PAA (polyacrylic acid)/PMA < PMMA. The ionic conductivity of the copolymer electrolytes based on PMMA with PEO is the highest, which is mainly because of its better complexing performance and flexibility. 

Sequential IPNs based on PMA and PMMA were prepared by UV photopolymerization [301]. The PMA/PMMA system is immiscible and so, for... 

UV light, at r.t., in bulk, PMMA, PMAc-co-PEGDMA, under inert atmosphere PMMA-co-PMA, PMMA-co-PSt ... 

The Arrhenius frequency factors [log(T/M V)] for addition of carbon centered radicals to the unsubstiUited terminus of monosubslituted or 1,1-disubstituted olefins cover a limited range (6.0-9.0), depend primarily on the steric demand of the attacking radical and are generally unaffected by remote alkene substituents. Typical values of log(T/M" V) are ca 6.5 for tertiary polymeric (e.g. PMMA ), ca 7.0 for secondary polymeric (PS, PMA, and ca 7.5, 8.0 and 8.5 for small tertiary (e.g. /-C4H9 ), secondary (i-CiH ) and primary (CHj, CbHs ) radicals respectively (Section 4.5.4).4 For 1,2,2-trisubstituted alkenes the frequency factors arc about an order of magnitude lower.4 The trend in values is consistent with expectation based on Iheoretical calculations. 

Fig. 2. Scatmu electron micrographs (JNM-ECP400-JEOL) of PMMA particles produced with different surfectaats (A) PDMS- OH (5.0 wt %), (B) PDMS-itiA (5.0 wt %). (C) PDMS-h-P(MMA(l.lK)-eo-MA(0.5K)) (5.0 wt %), (D) PDMS4b-P(MMA(l.lK)-co-MA(0.5K)) (10.0 wt %), (E) PDMS-co-PMA (5.0wt %), and (F) PDMS-co-PMA (10.0 wt %). Parameters in the paranthrais are wt % of surfactant with respect to monomer.

The reactions were carried out in dilute homogeneous solution in dipolar aprotic solvents ([ester]g=0.2-0.4 mole.l- ) using stereoregular (pure I or S) or predominantly syndiotactic radical (R) PMMA, polymethylacrylate (PMA) and radical azeotropic styrene-MMA copolymer (PSMMA, MMA mole.fraction = 0.47) as well as model monomeric (methylpivalate) and dimeric (dimethylglutarate) compounds. The overall reaction is outlined in the simplified scheme ... 

The first diblock copolymer brushes synthesized in our group were made by a combination of carbocationic polymerization and ATRP (Scheme 1) [46]. Zhao and co-workers [47] synthesized diblock copolymer brushes consisting of a tethered chlorine-terminated PS block, produced using carbocationic polymerization, on top of which was added a block of either PMMA, poly(methyl acrylate) (PMA) or poly((Ar,M -dimethylamino)ethyl methacrylate) (PDMAEMA), synthesized using ATRP. The thickness of the outer poly(meth)acrylate block was controlled by adding varying amounts of free initiator to the ATRP media. It has been reported that the addition of free initiator is required to provide a sufficiently high concentration of deactivator, which is necessary for controlled polymerizations from the sur-... 

PS—polystyrene, PMMA—poly(methyl methacrylate), PMA—poly(methyl acrylate), PDMAEMA—poly((Nd f-dimethylamino)ethyl methacrylate), PDMA—poly( dimethyl-acrylamide), P(t-BA)—poly(tert-butyl acrylate), PAA—poly(acrylic acid), PPFS—poly (pentafluorostyrene), PHFA—poly(heptadecafluorodecyl acrylate)... 

The temperature optimization for the RAFT polymerization of EAA revealed an optimum reaction temperature of 70 °C. Block copolymers with a poly(methyl acrylate) (PMA), a poly(n-butyl acrylate) (PnBA), a PMMA, or a poly(A,A-dimethyl aminoethyl methacrylate) (PDMAEMA) first block and a poly(l-ethoxyethyl acrylate) (PEEA) second block were successfully synthesized in an automated synthesizer. The synthesis robot was employed for the preparation of 16 block copolymers consisting of 25 units of the first block composed of PMA (exp. 1 ), PnBA (exp. 5-8), PMMA (exp. 9-13), and PDMAEMA (exp. 13-16) and a second block of PEEA consisting of 25, 50, 75, or 100 units, respectively. The first blocks were polymerized for 3 h and a sample from each reaction was withdrawn for SEC analysis. Subsequently, EAA was added and the reactions were continued for 12 h. The molar masses and PDI values of the obtained block copolymers are shown in Fig. 15. 

Fig. 15 Number average molar masses (Mn opc) and PDI values obtained for the first blocks and for the final copolymers of PMA, PnBA, PMMA, or PDMAEMA (25 units) with PEEA (25, 50, 75, and 100 units for 100% conversion). AH Mn pc values are calculated against PMMA standards. SEC eluent CHClsiNEtsii-PrOH. (Reprinted with permission from [87]. Copyright (2005) American Chemical Society)...

Since alpha substituents also impede segmental motion, PMMA (Tg = 378 K) has a higher Tg than polymethyl acrylate (PMA) (7 = 279 K). The various factors which affect Tg values are additive. 

Most general purpose linear polymers, such as polyolefins, PS, PVC, and polymethyl methacrylate (PMMA), are not suitable for use at temperatures above 100 °C. PMMA and other polymers of 1,1-substituted vinyl monomers, such as poly-a-methylstyrene, decompose almost quantitatively to their monomers at elevated temperatures. However, the Tg and Tm values of these polymers are greater than those of polymers from 1-substituted vinyl monomers. For example, the Tg values of polymethyl acrylate (PMA) and PMMA are 276 and 381 K, respectively. 

There is some reason to expect that conversion of the anhydride to a half-ester might reduce the sensitivity of the copolymers. Hiraoka (10) determined the relative sensitivities of PMMA, PMA (polymethacrylic acid) and PMA AN (polymethacrylic anhydride) by measuring the gaseous products (CO, C02, and H2) given off when these polymers were exposed to electron beam radiation of 2.5 keV at 297 °K. He found that the G values (number of chemical events produced per 100 eV of absorbed radiation) for the removal of side groups are 2.0, 7.4 and 16 for PMMA, PMA and PMA AN, respectively. Anderson (11) found a similar relative order of sensitivity. For copolymers of methylmethacryate with 25% dimethylitaconate, 25% monomethyl itaconate or 25% itaconic acid (or anhydride) the G(s) values were 1, 2, 3, respectively. For the copolymer of alpha-methylstyrene and monomethyl maleate, on the other hand, we find an increase in sensitivity by a factor of 2.5 over the corresponding anhydride as described below. 

Recently, the concept of an ambidextrous surfactant, which is active at an organic-C02 and organic-water interface, was demonstrated as shown in Figure 8.10. The surfactants included a PDMS block, a poly(methacrylic acid) (PMA) or poly(acrylic acid) block, and, in some cases, a third PMMA... 

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