Synthesis of comb graft copolymersI–Ring‐opening metathesis polymerization of norbornyl‐polymethacrylate by a supported ruthenium carbene complex generated in situ

AbstractThe Diels–Alder reaction of cyclopentadiene (CPD) and allyl chloride (AC) was carried out by using BF3·Et2O or its supported counterpart on tailor‐made polystyrene supports as catalysts. The activity of the latter is double that of the former, and the yield of the product 5‐chloromethyl‐2‐norbornene (NBCH2Cl) reached up to 67.4%. Then, via living anionic polymerization, a cycloolefinyl macromonomer, 5‐PMMA‐2‐norbornene (NB‐PMMA), was synthesized using NBCH2Li as the initiator which in turn was prepared by a lithiation reaction of NBCH2Cl in THF. Comb‐shaped graft copolymer PNB‐g‐PMMA was finally synthesized via ring‐opening metathesis polymerization (ROMP) of the synthesized macromonomer NB‐PMMA under the catalysis of a polymer‐supported ruthenium carbene complex generated in situ. The polymer‐supported carbene species shows much better initiation behavior than its unsupported counterpart. In both cases, that is in the Diels–Alder reaction and ROMP, the effect mechanism of the tailored supports of the catalysts is discussed. Copyright © 2003 John Wiley & Sons, Ltd.