MECHANICAL SCISSION OF PERFLUOROPOLYETHERS

被引:38
作者
KARIS, TE
NOVOTNY, VJ
JOHNSON, RD
机构
[1] Ibm Research Division, Almaden Research Center, San Jose, California, 95120-6099
关键词
D O I
10.1002/app.1993.070500807
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Mechanical scission of two typical perfluoropolyethers was investigated: Y, a copolymer of -CF(CF3)CF2O-, -CF2O-, and -CF(CF3)O-, and Z, a copolymer of - (CF2)nO-, with n = 1, 2, 3, 4. Undiluted polymers were subjected to prolonged shearing in a media mill with ZrO2 particles. A chemical extraction of the polar ZrO2 particles was carried out to collect adsorbed polar scission products. Mechanochemical scission products from both the Y and Z fluorocarbon polymers were identified by F-19-NMR. A significant amount of CF3CO2- was present after the milling and the primary functional groups formed at scissioned chain ends were -CO2-. A hydrodynamic expression was derived and the maximum extension rate was estimated to be in the range of 5 X 10(6) s-1. Initial degrees of polymerization were between 20 and 200, well below levels for which flow-induced scission is expected to occur. Final degrees of polymerization were less than 10, and the scission was noncentral and nonrandom in both polymers. (C) 1993 John Wiley & Sons, Inc.
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页码:1357 / 1368
页数:12
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