Polyepichlorohydrin elastomer other

The complicated pattern for the methylene carbon of the polymers indicates the presence of an irregular structure of head to head and tail to tail linkages. On the other hand, the uniformly head to tail structure of polyepichlorohydrin elastomers made by the coordination catalyst shows a doublet for the methylene carbon at 70.2 and 70.0 ppm (21). No peak corresponding to the terminal methine or chloromethyl carbons is detected in elastomers. 

Polyepichlorohydrin (PECH) is well known as a reactive elastomer. Displacement at the carbon-chlorine bond of PECH has been accomplished with a wide variety of nucleophilic reagents, for the purposes of polymer modification, grafting and crosslinking (1, 2). On the other hand, the PECH structure (1) is hardly optimal from the point of view of its reactivity as a substrate for nucleophilic... 

Table II summarized the ratios of major absorbances of HTE liquid polymers. Only the ratio of hydroxyl absorbance is sensitive to the molecular weight, whereas the other two ratios are independent of it. For comparison, the ratios of absorbances of high molecular weight elastomers (Hydrin 100) made by a coordination catalyst (R3AI/H2O) are also shown in Table II. No hydroxyl absorbance is detected. The two ratios of CH/CO and CC1/C0 absorbances of HTE liquid polymers match well with those of elastomers and are characteristic feature of polyepichlorohydrin.

Some specialty elastomers are used in mature markets, such as nitrile rubber and polychloroprene. Others such as polyepichlorohydrin rubber have not found their... 

Elastomers containing polyepichlorohydrin, also known as ECO, CO, or GECO according to ASTM, offer an excellent balance of properties, combining certain desired dynamic properties of namral mbber (NR), with much of the fuel, oil, and chemical resistance of other specialty elastomers such as nitrile (NBR), polyacrylate (ACM), and neoprene (CR) mbbers. The combination of the basic properties of oil, fuel, heat, low-temperature flexibility, and ozone resistance imparted by the saturated main chain and the chlorine groups, coupled with low permeability, makes polyepichlorohydrin a very useful elastomer for automotive applications. Specific applications include fuel hoses, emission tubing, air ducts, seals, and diaphragms. 

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