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Waterborne epoxy dispersions have been employed effectively for many years in response to environmental regulations aimed at reducing solvent levels in coatings. Very few non-toxic bio-based polyamines have been reported in the literature as curing agents for epoxy-functional waterborne dispersions. Currently to our knowledge the only bio-based amino hardener used to cure a waterborne epoxy prepolymer is ϵ-polylysine. Being one of the rare primary amine-containing polymers of natural origin, chitosan is produced commercially by the deacetylation of chitin. In the work reported here, chitosan and oligochitosan were evaluated as curing agents for diepoxy prepolymers. A solvent-free prepolymer (Epotec) and a waterborne prepolymer dispersion (Epirez) were both used. A crosslinked network was obtained when the reaction was performed with the waterborne epoxy dispersion. The influence of the hardener-to-epoxy prepolymer ratio on the crosslinking density was investigated. The thermal properties of networks were measured using differential scanning calorimetry and thermogravimetric analysis. © 2013 Society of Chemical Industry

The successful activation observed when using ButP4 phosphazene base and thiophenol or bisthiols for the anionic ring opening polymerization (ROP) of di-n-propyl cyclopropane-1,1- dicarboxylate is described. Well-defined monofunctional or difunctional polymers with a very narrow molecular weight distribution were obtained through a living process. Quantitative end-capping of the propagating malonate carba- nion was accessible by using either an electro- philic reagent such as allyl bromide or a strong acid such as HCl. Kinetics studies demonstrated a much higher reactivity compared to the conven- tional route using alkali metal thiophenolates.

Summary: The paper reviews recent developments in synthesis and characterization of regioselectively functionalized cellulose derivatives. It demonstrates the importance of protecting groups like triphenylmethyl- and thexyldimethylsilyl (TDMS) ethers in cellulose chemistry. The protected cellulose derivatives can be used for the preparation of 2,3-O-functionalized polymers. Moreover, the TDMS group opens up the synthesis of 3-O-ethers of cellulose that possess interesting properties in terms of structure in solution, water-solubility, and thermoreversible gelation.