Synthesis of a new type both-end-capped poly(oxymethylene) with a long alkyl group

A new type both-end-capped poly(oxymethylene) with a long alkyl group was s ynthesized. Using formaldehyde methyl octadecyl acetal as the chain transfe r agent for the polymerization of trioxane, the both-end-capped poly(oxymet hylene) with a methoxy group and octadecyloxy group was obtained. Almost al l the formaldehyde methyl octadecyl acetal in the polymerization mixture is consumed. Formaldehyde methyl octadecyl acetal is confirmed to be chemical ly bonded in poly(oxymethylene) derived from H-1-NMR measurements. For the case of using formaldehyde di(octadecyl) acetal as the chain transfer agent , almost all the formaldehyde di(octadecyl) acetal in the polymerization mi xture is consumed. Direct proof that formaldehyde di(octadecyl) acetal is c hemically bonded in poly(oxymethylene) was obtained. The reduced viscosity of the polymer showed a complicated behavior. This suggested that some aggr egation of the octadecyl group of the polymer chain-end took place in the s olution. For the case using formaldehyde methyl acetal of the carbon number 38 alcohol, the polymer obtained showed the melting behavior at 95 degrees C, which could be attributed to the melting of the long alkyl group. The r educed viscosity also suggested an aggregation of the long alkyl group of t he polymer chain end in the solution. The observed amount of the C38H77 gro up, which was calculated from the observed value of methylene linkage by H- 1-NMR, was lower than the calculated value based on the feed C-38 H77OCH2OC H3. This fact suggests that the methylene linkage of the C38H77 group may p rovide a strong aggregation in the solution.