Polymerization model substrates, substituted

The calculated chemical shifts are based upon additivity factors for the sulfone, isopropylidene, and oxyphenyl linkages derived from the spectrum of T. The spectra of derivatives with D.F.=2 establish the chemical shifts of the 3-substltuted rings. Studies on model compounds with D.F.=1 confirm that the spectra of partially substituted samples can be calculated by appropriate combination of the spectra of unsubstituted and 3-substltuted rings. Quantitative substitution Is difficult to achieve with polymeric substrates, but Interpretation of spectra of low D.F. derivatives Is straight forward. 

In addition to providing many new precursors to functionalized poly(alkyl/arylphosphazenes), the deprotonation/substitution reactions of these N-silylphosphoranimines serve as useful models for similar chemistry that can be carried out on the preformed polymers. New reactions and experimentation with reaction conditions can first be tried with monomers before being applied to the more difficult to prepare polymeric substrates. A considerable amount of preliminary work [e.g., with the silylated monomers (z z) and polymers (2 o) has demonstrated the feasibility of this model system approach. 

The present study reports the synthesis, characterization and thermal reactions of phenyl and carbomethoxy substituted norbornenyl imides. These substrates were designed to model the reactive end-caps of the PMR-15 resin and allow an assessment of the effect that conjugating substituents would have on the high temperature cure of such systems. The effect of these substituents on both monomer isomerization and polymerization is reported and a possible use of the phenyl substituent as a probe of polymer structure is suggested. 

Comyn [1] has pointed out that maximum bond strength and consequently greater adhesion between the substrate and polymer could be achieved with a monolayer of silane bound to both the adherend and adhesive. The current investigation was undertaken to evaluate the possibility of monolayer level depositions on silicon substrates by employing a few w -functionalized alkanoyl-substituted derivatives of APTES which will provide polar moieties as well. The interactions of these functionalized silanes covalently immobilized on silicon with octadecylamine and octadecanoic acid, used as models for basic and acidic polymeric adhesives, were also examined in this study. Characterization of the silanized surfaces as well as studies on their interactions with the above two chemical probes were carried out through ellipsometric and XPS measurements. 

Since ATRP polymerization yields a polymer with a terminal bromide moiety, this provides an ideal substrate for nucleophilic conversion to the requisite azide. The complimentary alkyne group necessary for click cyclization can then be incorporated into the initiating group. Poly(styrene) was selected for model studies because it provides an ideal substrate for this transformation as the terminal bromide is ben lic, and therefore highly activated towards nucleophilic substitution with sodium azide. 

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