Chemically-initiated solution polymerizations and radiation-initiated bulk polymerizations of isopropyl vinyl ether

The unusually high rates of polymerization of isopropyl vinyl ether initiated in bulk by high energy radiation, compared with other vinyl ethers, reported previously have been confirmed. The rates, molecular weights and heats of polymerization initiated by triphenylmethyl hexachlorantimonate have now been measured in methylene dichloride solution. Both methods of initiation are believed to involve essentially free ions. The chemically initiated polymerization rates however were similar to those found with the other vinyl ethers. The conflicting results are explained in terms of solvation effects rather than to differences in the methods of initiation. Qualitatively these results have been interpreted in terms of the Eyring theory of reaction rates between an unpaired ion and a neutral molecule.     

Interesterification of starch with methyl palmitate

Thermoplastic polymers derived from natural products have been prepared by interesterifying starch with methyl palmitate. The degree of substitution (DS) of the esters has been found to be strongly dependent upon catalyst concentration and the ratio of methyl palmitate to starch, but is largely independent of temperature and starch concentration over the range studied. Replacement of methyl palmitate with methyl esters of shorter chain acids does not appear to affect the DS. These observations are interpreted from the results of studies on the effect of DS on the solubility parameter, the nature of the interchain bonding and the specific gravity of the polymers.