Biofunctional Surfaces Based on Dendronized Cellulose

Hyperbranched Polymers in Modifying Natural Plant Fibers and Their Applications in Polymer Matrix Composites-A Review

Natural plant fibers have been widely used in the agricultural and forest industries, and even in the automobile industry, especially for producing fiber reinforced polymer matrix composites. However, the low mechanical properties of composites remain the key problem in the applications. A hyperbranched polymer has lots of advantages such as low viscosity, high reactivity, and so on. Multireactive end groups of hyperbranched polymers are ideal for modifying natural plant fibers to achieve better interface bonding between a fiber and resin matrix. This manuscript reviews some research advances in hyperbranched-polymer-modified natural plant fibers and summarizes the applications of the modified fibers in polymer matrix composites with a particular focus on the chemical modification of fibers and interface bonding.

Preparation of reactive fibre interfaces using multifunctional cellulose derivatives

Cellulose fibres have poor reactivity and limited potential for surface engineering with advanced chemical functionalization in water. In this work, cellulose fibres were decorated with azide functions by charge-directed self-assembly of a novel water-soluble multifunctional cellulose derivative yielding reactive fibres. Propargylamine and 1-ethynylpyrene were utilized as a proof of concept that alkyne molecules may react with the azide functions of the reactive fibres via copper(I)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAc) reaction in mild conditions. Chemical characterization of the fibres was carried out using classical techniques such as Raman-, fluorescence-, and UV-vis spectroscopy. Among other techniques, time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray spectroscopy (XPS), two-photon microscopy (TPM), and inductively coupled plasma mass spectrometry (ICP-MS) were useful tools for additional characterization of the fibres decorated with amino- or photoactive groups. The information gathered in this work might contribute to the basis for the preparation of reactive cellulose-based interfaces with potential application in CuAAc reactions.

Modification of arabinogalactan propargyl ethers by triazolyl functions

Polysaccharide arabinogalactan (AG) has been modified by triazolyl functions via the copper-catalyzed 1,3-dipolar addition of azides to propargyl ethers. A range of new AG triazolo derivatives bearing benzyl, 4-vinylbenzyl, 1-naphthylmethyl, (1-vinylimidazol-2-yl)methyl, (1-ethylimidazol-2-yl)methyl, (1-vinylbenzimidazol-2-yl)methyl, allyl, carboxymethyl (as Na-salt) substituents is prepared by "one-pot" approach from organic azides generated in situ and AG propargyl ethers. The latter (degree of substitution 2.0-2.2) are converted into 1,2,3-triazolo AGs in DMSO/water mixture in the presence of CuSO4·5H2O/sodium ascorbate/Et3N in 82-94% yields and with 60-100% conversion.