Cross-linking oligomers

Certain polymeric stmctures can also be blended with other coreactive polymers or multifunctional reactive oligomers that affect curing reactions when exposed to ir radiation. These coreactive polymers and cross-linking oligomers undergo condensation or addition reactions, which cause the formation of network stmctures (Table 9) (4,5,47). 

Cross-linking oligomers (mol wt -200-1000), containing multiple unsaturation, are used to promote rapid free-radical-induced propagation reactions leading to cross-linked strucmres [39]. 

From a practical stand point almost any of the lower-molecular weight vinyl monomers, cross-linking oligomers, and polymers can be blended with a high-molecular weight thermoplastic polymer to enhance cross-link density at lower dose rates [39]. The influence of various other additives on the efficiency of cross-linking of polymers will be highlighted in the subsequent sections. 

Polymer Systems Cross-Linking Oligomers Functional Groups Cross-Linking Reaction (Mechanisms) Reference n z z So C/3... 

The quantitative analysis of cross-linking data yields evidence about the structure of the homooligomer. The homooligomer is incubated with different concentrations of cross-linker, the reactions are stopped after a certain time, and the solutions are separated on an SDS gel. Monomers, cross-linked dimers, and so on appear in the gel. The relative amount of monomers and cross-linked oligomers is determined for each cross-linker concentration (e.g., by scanning the gel). From the amounts, the cross-linking probabilities between the single subunits are computed (and from this the structure). 

Cross-linking oligomer design/MW between cross-link sites or number of reactive sites, polarity, viscosity, shrinkage factor. 

Monomer, Cross-linking Oligomer Design / number of reactive sites, surface tension values, solubility parameters, viscosity, polar-nonpolar, shrinkage during polymerization ... 

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