Substitution Reactions on Halogenated Polyethylene
It has been previously demonstrated that halogenation of polyethylene single crystals can be selective. Bromination takes place primarily in the amorphous regions without destruction of the crystalline core. These substituted crystals show unique melting and annealing behavior. Given that a Br substituent has such a marked effect on properties it was of interest to examine the effects of a much larger substituent. This was accomplished by replacing Br with a toluene group via a Friedel Crafts reaction. Neutron activation analysis, FTIR and thermal analysis were used to examine the reaction products. These techniques show that Br had indeed been replaced by toluene. Further substitution is primarily in the 1,4 (para) position with some 1,3 (meta) substitution. The presence of bulky sub-stituents modifies the melting behavior of the lamellae. However the heat of fusion remains unchanged. The major effect on the melting process is the suppression of any reorganizational annealing behavior.
KeywordsNeutron Activation Analysis Substitution Reaction Bromine Content Melting Data FTIR Absorbance
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- 4.P. H. Teyessie and G. Smets, J. Polymer Sci., 20, 362 (1956).Google Scholar
- 5.D. J. Blundell and A. Keller, J. Macromol. Sci., Phys., B2, 337 (1968).Google Scholar
- 6.Perkin-Elmer Differential Scanning Calorimetry Model DSC-2 Instruction Manual, Section 403, Norfolk, Conn., 1974.Google Scholar
- 7.M. Equiluz, H. Ishida and A. Hiltner, J. Polymer Sci., Phys. Ed., 17, 894 (1979).Google Scholar
- 8.F. F. Bentley, L. D. Smithson and A. L. Rozek, Infrared Spectra and Characteristic Frequencies ~ 700-300 cm −1, 1, John Wiley & Sons, New York, 1968, p. 68.Google Scholar
- 9.I. R. Harrison, J. Polymer Sci., Poly. Phys. Ed., 11, 1002 (1973).Google Scholar
- 10.J. D. Hoffman and J. J. Weeks, J. Res. N.B.S., 66A, 13 (1962).Google Scholar
- 11.I. R. Harrison and E. Baer, Analytical Cal., Vol. 2, R.S. Porter and J. H. Johnson, Eds., Plenum Press, N.Y., 1970, p. 38.Google Scholar