Polymer-bound quinones

RA Barkhau, EW Malcolm, DR Dimmel. Insoluble Lignin Models (5) Preparation and Alkaline Condensation Reactions of a Polymer-Bound Quinone Methide. J Wood Chem Technol 14 17, 1994. 

Quinone diimines are capable of reacting rapidly with radicals formed during intensive mixing. The product, a polymer-bound PPD moiety, provides a polar functionality which is capable of improving polymer-filler interactions. In general the improvements can result in modest reductions in tangent delta (rolling resistance) and modest improvements in abrasion resistance. 

Polymer-bound periodate and iodate have been used for the oxidation of quinols to quinones in high yield (>90%) [31]. 

The observation that quinone formation on a polymer-bound Co(NMesalpr) catalyst is favored against diphenoquinone formation by higher cobalt loadings [40] is indirect evidence for cobalt involvement after the H-atom abstraction step. Significantly, with... 

It should be mentioned that few, if any, examples are known of carbon-containing species chemisorbed at electrodes that are directly electroactive like H or OH/O species. Only in the case of adsorbed quinones or polymer-bound redox functions at chemically modified electrodes is direct surface electroactivity known. Some organic sulfide/disulfide pairs such as cystine/cys-teine are also electroactive when adsorbed. 

The polymer boxmd peroxocomplexes prepared in the present work have excellent catalytic potentiality and selectivity in the production of quinones. The chromium peroxocomplexes loses its activity on reaction and could be regenerated. The pwlymer bound vanadium catalyses sharpless epoxidation reactions. The high pore volume and a marginally good surface area shows that GMA-EGDM copolymers are good choice as supports. 

Elastomers cured with two crosslinking systems such as sulphur and the polymerisation products of p-benzoquinone are shown to have much improved overall mechanical properties. Non-Gaussian behaviour of quinone polymer crosslinked elastomers viewed as bimodal networks was studied. The study focused on the effect of ageing time on the reduced stress values of the networks in relation to the elongation of the samples. The study is also extended to cover the possible effect of these bound antioxidants on the onset of the vulcanisation process and the hardness values of the elastomeric networks. 15 refs. 

---