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preface to fifteenth edition

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POLYMERS, RUBBERS, FATS, OILS, AND WAXES 10.9<br />

10.3.2.2 Poly(methyl Acrylate). The monomer used for preparing poly(methyl acrylate) is produced<br />

by the oxidation of propylene. The resin is made by free-radical polymerization initiated by<br />

peroxide or azo catalysts and has the following formula:<br />

Resins vary from soft, elastic, film-forming materials <strong>to</strong> hard plastics.<br />

10.3.2.3 Poly(acrylic Acid) and Poly(methacrylic Acid). Glacial acrylic acid and glacial methacrylic<br />

acid can be polymerized <strong>to</strong> produce water-soluble polymers having the following structures:<br />

These monomers provide a means for introducing carboxyl groups in<strong>to</strong> copolymers. In copolymers<br />

these acids can improve adhesion properties, improve freeze-thaw and mechanical stability of polymer<br />

dispersions, provide stability in alkalies (including ammonia), increase resistance <strong>to</strong> attack by<br />

oils, and provide reactive centers for cross-linking by divalent metal ions, diamines, or epoxides.<br />

10.3.2.4 Functional Group Methacrylate Monomers. Hydroxyethyl methacrylate and dimethylaminoethyl<br />

methacrylate produce polymers having the following formulas:<br />

The use of hydroxyethyl (also hydroxypropyl) methacrylate as a monomer permits the introduction<br />

of reactive hydroxyl groups in<strong>to</strong> the copolymers. This offers the possibility for subsequent crosslinking<br />

with an HO-reactive difunctional agent (diisocyanate, diepoxide, or melamine-formaldehyde<br />

resin). Hydroxyl groups promote adhesion <strong>to</strong> polar substrates.<br />

Use of dimethylaminoethyl (also tert-butylaminoethyl) methacrylate as a monomer permits the<br />

introduction of pendent amino groups which can serve as sites for secondary cross-linking, provide<br />

a way <strong>to</strong> make the copolymer acid-soluble, and provide anchoring sites for dyes and pigments.<br />

10.3.2.5Poly(acrylonitrile).<br />

Poly(acrylonitrile) polymers have the following formula:<br />

10.3.3 Alkyds<br />

Alkyds are formulated from polyester resins, cross-linking monomers, and fillers of mineral or glass.<br />

The unsaturated polyester resins used for thermosetting alkyds are the reaction products of polyfunctional<br />

organic alcohols (glycols) and dibasic organic acids.

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