Polyacrylics PMMA

Examples of photothermoplasts include polyacrylates, polyacrylamides, polystyrenes, polycarbonates, and their copolymers (169). An especially well-re searched photothermoplast is poly(methyl methacrylate) (PMMA), which is blended with methyl methacrylate (MMA) or styrene as a monomer, and titanium-bis(cyclopentadienyl) as a photoinitiator (170). 

ACPA azobis(4-cyanopentanoic acid) AIBN azobis isobutyronitrile) BPO benzoyl peroxide DVB divinyl benzene, EGA 2-ethylcyano-acrylate HPC hydroxypropyl cellulose MMA methyl methacrylate PAAc polyacrylic acid PEI polyethyleneimine, PEO/PPO polyethylene oxide/polypyropylene oxide copolymer PVME polyvinylmethylether PVP polyvinylpyrrolidone K-30 DMSO dimethylsulfoxide PGA polyglutaraldehyde CMS chloromethylstyrene PMMA-g-OSA polymethylmethacrylate grafted oligostearic acid. 

The soapless seeded emulsion copolymerization method was used for producing uniform microspheres prepared by the copolymerization of styrene with polar, functional monomers [115-117]. In this series, polysty-rene-polymethacrylic acid (PS/PMAAc), poly sty rene-polymethylmethacrylate-polymethacrylic acid (PS/ PMMA/PMAAc), polystyrene-polyhydroxyethylmeth-acrylate (PS/PHEMA), and polystyrene-polyacrylic acid (PS/PAAc) uniform copolymer microspheres were synthesized by applying a multistage soapless emulsion polymerization process. The composition and the average size of the uniform copolymer latices prepared by multistage soapless emulsion copolymerization are given in Table 11. 

Various additives show considerable extraction resistance, such as impact modifiers (polyacrylates and polyblends PVC/EVA, PVC/ABS, etc.), highpolymeric processing aids (PMMA-based), elastomers as high-MW plasticisers, reactive flame retardants (e.g. tetrabromobisphenol-A, tetrabromophthalic anhydride, tetrabromophthalate diol, dibromostyrene). Direct measurement of additives by UV and IR spectroscopy of moulded films is particularly useful in analysing for additives that are difficult to extract, although in such cases the calibration of standards may present a problem and interferences from other additives are possible. 

Polystyrene > polystyrene/PMMA copolymer > PMMA > polystyrene/polyacrylic acid copolymer... 

Fig. 9.31 a) Synthesis of PS-b-polyacrylate brushes by LCSIP and consecutive ATRSIP [282]. AFM images of the tethered PS-fa-PMMA brushes with 23 nm thick PS layer and 14 nm thick PMMA layer b) after treatment with CH2CI2, c) with cyclohexane and d) after solvent exchange from CHjClj to cyclohexane, e) Cartoon proposing a model for the regular nanopattern morphology ( pinned micelles )... 

Another interesting positive-tone polyacrylate DUV resist has been reported by Ohno and coworkers (82). This material is a copolymer of methyl methacrylate and glycidyl methacrylate. Such materials are negative e-beam resists, yet in the DUV they function as positive resists. Thermal crosslinking of the images after development provides relief structures with exceptional thermal stability. The reported sensitivity of these copolymers is surprising, since there are no obvious scission mechanisms available to the system other than those operative in PMMA homopolymer, and the glylcidy side-chain does not increase the optical density of the system. 

Polymethylmethacrylate (PMMA) Polyisodecylmethacrylate Polyacrylic acid (PAA) Polyacrylamide (PAAm) Hydrolyzed polyacrylamide Glyoxylyzed polyacrylamide Polyisobutylene (PIB) Polyethyleneoxide (PEO) Polystyrene Polystyrenesulfonate Polyethylenimine (PEI) Polyvinylalcohol (PVA) Polyvinylpyrrolidone (PVP) Poly-cw-isoprene (PCIP)... 

The acrylic plastics use the term acryl such as polymethyl methacrylate (PMMA), polyacrylic acid, polymethacrytic acid, poly-R acrylate, poly-R methacrylate, polymethylacrylate, polyethylmethacrylate, and cyanoacrylate plastics. PMMA is the major and most important homopolymer in the series of acrylics with a sufficient high glass transition temperature to form useful products. Repeat units of the other types are used. Ethylacrylate repeat units form the major component in acrylate rubbers. PMMAs have high optical clarity, excellent weatherability, very broad color range, and hardest surface of any untreated thermoplastic. Chemical, thermal and impact properties are good to fair. Acrylics will fail in a brittle manner, independent of the temperature. They will suffer crazing when loaded at stress about halfway to the failure level. This effect is enhanced by the presence of solvents. 

Phosphrno polyacrylic acid (P-PAA), 355 Photon echo signal, 415 PLD. See Pulsed laser deposition PMMA. See Poly(methyl methacrylate) Poly(alkylamine hydrochloride) (PAH), 415 Poly(ethylene glycol) (PEG), 284, 285, 288, 324, 328... 

For coupling to be selective, the chain to be coupled must be end-capped by mutually reacting groups. For example, a living anionic polyacrylate or polymethacrylate can be directly coupled to any polymer or copolymer end-capped by a suitable electrophile. Fladjichristidis and coworkers coupled living anionic PMMA chains with the living PtBuA anion of PS- Zoc -PtBuA by reaction with l,2-bis(bromomethyl)benzene, with formation of a triblock copolymer . ... 

Properties of Dispersions and Polymers. All polymer dispersions with SDS (sodium dodecyl sulfate) as an emulsifier were stable for at least 8 months. Dispersions with Na laurate as emulsifier flocculated after a short time. Polyacrylates on drying yielded clear and coherent films polystyrene and PMMA dispersions gave opaque and brittle layers. The doses needed for polymerization were well below a dose which causes cross linking or degradation. 

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 ... 

The resulting PMMA composite materials are insoluble in both organic or aqueous media. Hence alternative acrylates soluble even in their polymerized state have been sought for. Especially poly-tert-butyl acrylates suit weU to this purpose. Furthermore, the tert-butyl residues are easy to remove from these composites, so water soluble polyacrylic acids with additional carbon nanotubes are obtained. 

The support of United States Public Health Service under Grant HL 20079 is gratefully acknowledged. J. J. Wu synthesized the PMMA and the polyacrylates. The cross-linked poly(vinyl alcohol) was prepared by John Frenz as part of his M. S. thesis (MIT, Department of Chemical Engineering, January 1980). 

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