Synthesis of a New Type Poly (oxymethylene) with a Terminal Unit of Long Alkyl Group Using Stearyl Alcohol as a Chain Transfer Agent†

Hajime NAGAHARA††, Keisuke YAJIMA and Junzo MASAMOTO*

Department of Polymer Science and Engineering, Kyoto Institute of Technology; Matsugasaki, Sakyo-ku, Kyoto-shi 606-8585 Japan
†† Division of Research and Development, Asahi Chemical Industry Co. Ltd.; Yuraku-cho, Chiyoda-ku, Tokyo 100-8440 Japan

The authors synthesized a new type poly (oxymethylene) with a long alkyl group using stearyl alcohol (1-octadecanol) as a chain transfer agent during the polymerization of trioxane. In the case of solution polymerization of trioxane using 1,2-dichloroethane as a solvent and 1,3-dioxolane as a comonomer, it was found by gas-chromatographical method that during the polymerization most stearyl alcohol fed to the polymerization system was consumed, and by 1H-NMR method octadecyl unit was confirmed in polymer. However, there was some difference between the consumed stearyl alcohol and octadecyl unit found in polymer. It was observed that the octadecyl unit in polymer was less than the consumed stearyl alcohol. It was deduced that the low molecular weight oxymethylene copolymer with relatively higher comonomer incorporation was soluble to the methanol, which was used as a washing solvent. In the case of bulk polymerization of trioxane using no solvent, fairly good agreement was observed between the consumed stearyl alcohol and octadecyl unit found in polymer except in the case of high feed of stearyl alcohol. 1H-NMR analysis of the obtained polymer showed that the proton of some methylene of octadecyl group attached to the polymer end shifted to the lower magnetic field compared to that of the free stearyl alcohol. The oxymethylene unit connected to the stearyl group was also observed at 4.87 ppm, which proved octadecyl group was surely connected to the poly (oxymethylene) end.
† Synthesis of End-Group Modified Poly (oxymethylene) by Chain Transfer Reaction. Part 1.
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