Glass transformation temperatures of poly(vinyl alkyl ethers) and poly(vinyl alkyl sulfides)

A number of poly(vinyl alkyl ethers) and poly(vinyl alkyl sulfides) of reasonably high molecular weight were prepared. Glass transformation temperatures T g of the various polymers were measured dilatometrically. In general, the T g value decreased with increasing length of the n ‐alkyl group. Data relating T g values of poly(vinyl n ‐alkyl ethers) with length of n ‐alkyl group were treated in terms of free volume concepts of the liquid state. Branching on the alkyl group of the polymer increased the T g value. Poly(vinyl n ‐alkyl sulfides) had T g values about 35°C. higher than their oxygen analogs. A comparison of poly(vinyl n ‐alkyl ethers) and polymers of normal α‐olefins showed that the ether group and methylene group in side chains were equivalent in influencing the glass transformation temperatures. From a comparison of poly(vinyl n ‐alkyl ethers) and poly( n ‐alkyl methacrylates) it is concluded that the nature of the backbone is important in determining the ease with which side chain crystallization takes place.