Phenoxy polymer

These materials are part of the technology of epoxy resins that are discussed in a separate section, further on in this chapter. The polymers bridge a gap between thermosetting resins and thermoplastic polymers and are used in both forms commercially. An idealized picture of phenoxy polymers can be shown as follows  

Theoretically, the phenoxy resins should form in equimolar reactions of epichlorohydrin with the diphenol. There are, however, a number of side reactions that accompany die condensation. To get around them and to obtain high molecular weight polymers, the syntheses are carried out in two steps. In the first, an excess of epichlorohydrin is used to form diepoxide  

In the second step, equimolar quantities of the diepoxide are reacted with the diphenol  

Both reactions are conducted in solution, where methyl ethyl ketone is the choice solvent. The commercial resins range in molecular weights from 15,000-200,000. 

Polyacetals and polyketals are polyethers that form (1) through condensations of glycols with carbonyl compounds, (2) by exchange reactions of acetals or ketals, and (3) by additions of diols to dialkenes  

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When X in formula 1-22 is about 100, the polymers are known as phenoxy resins. Although further molecular weight increase can be accomplished by reaction on the pendant hydroxyls in the molecule, commercial phenoxy polymers already have sufficient strength to be formed directly into articles. They would be in the finite-strength region of curve B in Fig. 1-1. (The major current use for these polymers is in zinc-rich coatings for steel automobile body panels.)... 

The commercially available phenoxy resin has Mw around 50,000 and little epoxy functionality. The phenoxy polymer is then classified as a polyol or a po-ly(hydroxy ether) [3]. Typical applications for the phenoxy resin are as hot-melt adhesives, coatings for beverage cans, and toughening agents for various epoxy resin formulations. The viscoelastic properties of phenoxy resins have been studied by Alegria et al. [11-15]. The phenoxy polymer can be used as a reference in the viscoelastic study of DGEBA oligomer. 

Uses Phenolic, adhesion promoter, chem. resist, aid for drum and pail coatings, latex and phenoxy polymers crosslinking agent for water-based polymers intended for low VQC applies. food pkg. adhesives, coatings, paper, closures with sealing gaskets for food containers Features Thermosetting compat. with various waterborne acrylic, epoxy, and phenoxy resins... 

Uses Phenolic for highly chem. resist, drum and pail coatings for rigid surfaces, pipe coatings latex modifier to improve chem. resist, and adhesion cro inking agent for latex and phenoxy polymers Features Exc. corrosion resist. 

Bisphenol A phenoxy polymers and bisphenol A polycarbonates were blended in solution. Chemical changes from aromatic to aliphatic carbonate groups were monitored by FTIR as a function of time and temperature (348). 

Table 4.1 Relative volumes of CO and CO2 evolved from phenoxy polymers during UV irradiation [741]...

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