Page 196 - Handbook of Plastics Technologies
P. 196
THERMOSETS
3.66 CHAPTER 3
FIGURE 3.74 Copolymerization of cellulose with methylol resins.
3.1.8.8 Phenoxy Resin. The –OH groups in phenoxy resin (Fig. 3.75) can be cross-
linked by methylol, epoxy, aldehyde, acid, and isocyanate groups for various specialty ap-
plications.
3.1.8.9 Casein. The amide groups in casein protein are reactive enough for useful cross-
linking. Casein is plasticized with water and then extruded or molded. To improve proper-
ties, the products are then soaked in formaldehyde solution to cross-link the amide groups
(Fig. 3.76). This is used to make products such as buttons and buckles.
3.1.9 Cross-Linking of Elastomers, Coatings, and Adhesives
Cross-linking is used not only in thermoset plastics but also in the related fields of elas-
tomers, coatings, and adhesives. A review of these fields can broaden our view and hope-
FIGURE 3.75 Phenoxy resin.
FIGURE 3.76 Casein—formaldehyde cross-linking.
Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com)
Copyright © 2006 The McGraw-Hill Companies. All rights reserved.
Any use is subject to the Terms of Use as given at the website.
