Elastomeric polyethers

The flexible backbone of an aliphatic polyether chain can lead to polymers with a low glass transition temperature. Providing crystallisation can be inhibited by 

This approach was used in the development of the epichlorhydrin rubbers which became commercially available around 1965 from Goodrich (Hydrin) and Hercules (Herclor). Both homopolymers of epichlorhydrin (Hydrin 100, Herclor H) and copolymers of epichlorhydrin with ethylene oxide (Hydrin 200, Herclor C) became available. (In 1986 Hercules sold their interest in these materials to Goodrich, who in turn later sold this to Nippon Zeon). 

The polymers are amorphous with brittle points (quite closely related to the Tg) of about -15°C and - 0°C respectively. 

Vulcanisation can be effected by diamines, polyamines and lead compounds such as lead oxides and basic lead phosphite. The homopolymer vulcanisate is similar to butyl rubber in such characteristics as low air permeability, low resilience, excellent ozone resistance, good heat resistance and good weathering resistance. In addition the polyepichlorohydrins have good flame resistance. The copolymers have more resilience and lower brittle points but air impermeability and oil resistance are not so good. The inclusion of allyl glycidyl ether in the polymerisation recipe produces a sulphur-curable elastomer primarily of interest because of its better resistance to sour gas than conventional epichlorhydrin rubbers. 

Epichlorhydrin rubbers, whilst being speciality materials, have a useful combination of properties which leads to their use in many applications such as gaskets, oil-field components, fuel pump diaphragms, oil seals, fuel and hydraulic hose and printing rollers. 

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Elastomeric polyether-ester block copolymers were prepared by melt transesterification of poly(tetramethylene ether) glycol of molecular weight approximately 1000 with a variety of diols and esters. The ease of synthesis and the properties of these thermoplastic copolymers have been related to the chemical structure and concentration of the ester hard segments. 

Thomas et al. [1986] studied the effect of gamma irradiation (1,10,100 and 500 kGy) on PVC/TPE = 100 0, 75 25, 50 50, 25 75 and 0 100 blends (Table 11.9). As TPE a thermoplastic, elastomeric polyether-ester block copolymer of 1,4-butane-diol-polybutylene and glycol-terephthalic acid copolymer (ElytreF ), was used. The blends were prepared in an internal cam-type mixer at 80 rpm, 180°C, mixing time 7 min. TPE was added first,... 

The polymers are elastomeric polyethers, sold under the Stat-Rite S-Series in alloys with base polymers such as acetal, ABS, PP, PETG, and others. The conductive polymer reportedly has minimal effect on the mechanical properties of the base resin. Prices are higher than carbon-black filled systems, but lower than carbon-fiber materials. 

T his book is based largely on the papers presented at a Polyether - Symposium in honor of Dr. Charles C. Price, Benjamin Franklin Professor of Chemistry at the University of Pennsylvania, on the occasion of his receiving the Creative Invention Award of the American Chemical Society for his pioneering U.S. Patent 2,866,774 on elastomeric polyether urethanes. One of the symposium papers by N. Doddi, W. C. Forsman, and C. C. Price has already been published in /. Polymer Set., Polym. Phys. Ed. (1974) 12, 1395. In addition, two papers are included from P. Dreyfuss and T. Saegusa with S. Kobayashi, outstanding polyether researchers who were not able to participate in the symposium. 

A different method is based on the possibility of having block copolymers as a dispersed phase between PBT and elastomeric polyethers. The blends and the copolymers are obtained directly during the polymer-... 

Wolfe J R Jr (1977) Elastomeric polyether-ester block copolymers. I. Structure-property relationships of tetramethylene terephthalate/polyether terephthalate copolymers. Rubber Chem Technol 50 688-703. 

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