Cross-linking oligomers, effect

When cyclic alkenes are utilized as starting materials the metathesis reaction will lead to long chain polymers and/or cyclic oligomers [103, 104, 107, 108]. If a strained cyclic alkene is employed the reaction is effectively irreversible. Industrially cyclooctene (polymer Vestenamer), 2-norbornene (polymer Norsorex), and dicyclopentadiene (polymer Telene, Metton, Pentam) are used as monomers. Upon polymerization cyclooctene and 2-norbornene yield straight chain polymers while dicyclopentadiene also allows cross-linking (Scheme 5.56). 

UV-radiation is used to achieve rapid curing and to avoid set-off effects in offset printing. The binders in UV-inks are highly reactive acrylate monomers and oligomers to which photoinitiators are added. These initiators start the cross-linking reaction in response to UV-radiation. Photoinitiators are low... 

The hydrophobic microenvironments created on the cross-linked polystyrene may raise the intrinsic peptide-hydrolyzing activity of the metal center, as noted above. The microdomains created on the synthetic polymer may facilitate complexation of the protein substrate with the catalytic center. Possible inactivation of the metal center by formation of hydroxo- or oxo-bridged dimers or oligomers can be prevented upon immobilization of the metal center to a sohd support. Higher pH values inaccessible by a soluble metal complex can be attained by the corresponding immobilized metal complex. The enhancement in the proteolytic activity of the Cu(II) complex of cyclen upon attachment to the polystyrene may be attributed to some of these effects. 

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