Polydicyclopentadiene (PDCPD), marketed as Telene or Metton, is a highly cross-linked

Chapter 31, Problem 31

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Polydicyclopentadiene (PDCPD), marketed as Telene or Metton, is a highly cross-linked thermosetting resin used for molding such impactresistant parts as cabs for large trucks and earth-moving equipment. PDCPD is prepared by ring-opening metathesis polymerization of dicyclopentadiene, which is itself prepared from 1,3-cyclopentadiene. The polymerization occurs by initial metathesis of the more highly strained double bond in the bicyclo[2.2.1]heptane part of the molecule (Section 4-9) to give a linear polymer, followed by cross-linking of different chains in a second metathesis of the remaining cyclopentene double bond. Cyclopentadiene Dicyclopentadiene Polydicyclopentadiene 2 H H H H heat ROMP (a) Show the mechanism of the formation of dicyclopentadiene from cyclopentadiene. (b) Draw the structure of a representative sample of the initially formed linear polymer containing three monomer units. (c) Draw the structure of a representative sample of PDCPD that shows how cross-linking of the linear chains takes place.