are represented by the above formula wherein y is zero when y is other than zero i e terpolymers are employed the co ch 2 ch 2 units and the co g units are found randomly throughout the polymer chain and preferred ratios of y x are from about 0 01 to about 0 1 the precise nature of the end groups does not appear to influence the properties of the polymer to any considerable extent so that the polymers are fairly represented by the formula for the polymer chains as depicted above of particular interest are the polyketone polymers of number average molecular weight from about 1000 to about 200 000 particularly those of number average molecular weight from about 20 000 to about 90 000 as determined by gel permeation chromatography the physical properties of the polymer will depend in part upon the molecular weight whether the polymer is a copolymer or a terpolymer and in the case of terpolymers the nature of the proportion of the second hydrocarbon present typical melting points for the polymers are from about 175 u00b0 c to about 300 u00b0 c more typically from about 210 u00b0 c to about 270 u00b0 c.