The graft copolymerization of styrene and lignin. III. Chain transfer reactions of lignin and lignin model compounds

Authors

  • R. B. Phillips,

    1. Department of Chemical Engineering and Wood and Paper Science, North Carolina State University, Raleigh, North Carolina 27607
    Current affiliation:
    1. International Paper Company Corporate Research Center, Tuxedo Park, New York 10987
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  • W. Brown,

    1. Department of Chemical Engineering and Wood and Paper Science, North Carolina State University, Raleigh, North Carolina 27607
    Current affiliation:
    1. Department of Physical Chemistry, University of Uppsala, Sweden
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  • V. Stannett

    1. Department of Chemical Engineering and Wood and Paper Science, North Carolina State University, Raleigh, North Carolina 27607
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Abstract

The effect of addition of lignin model compounds on the polymerization rate and molecular weight of polymer in the radiation-induced polymerization of styrene was studied. Guaiacol, a model for softwood lignin, reacted slowly with styrene radicals, while 2,6-dimethoxyphenol, a hardwood lignin model, was a much more efficient chain transfer agent. Studies with isoeugenol indicate that allylic or phenoxy radical stability in a conjugated system may terminate polymerization quite effectively. The results are discussed in the light of new and previous data with isolated lignins; they are consistent with the previously presented grafting scheme.

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