Fatty esters of cellulose from olive pomace and barley bran: Improved mechanical properties by metathesis crosslinking

Olefin Cross-Metathesis in Polymer and Polysaccharide Chemistry: A Review

Olefin cross-metathesis, a ruthenium-catalyzed carbon-carbon double bond transformation that features high selectivity, reactivity, and tolerance of various functional groups, has been extensively applied in organic synthesis and polymer chemistry. Herein, we review strategies for performing selective cross-metathesis and its applications in polymer and polysaccharide chemistry, including constructing complex polymer architectures, attaching pendant groups to polymer backbones and surfaces, and modifying polysaccharide derivatives.

Fluorescent Covalently Cross-Linked Cellulose Networks via Light-Induced Ligation

A facile light-induced procedure for the covalent cross-linking of cellulose at ambient conditions employing the nitrile imine mediated tetrazole-ene cycloaddition (NITEC) reaction is presented. Cellulose-tetrazoles with 2 degrees of substitution (0.14 and 0.23) were synthesized in a solution-based transesterification procedure in an ionic liquid. Two bismaleimides with either a trioxatridecane or a dithiodipropionyl backbone were used as cross-linkers to form fluorescent, covalently cross-linked cellulose networks and films, which were characterized by UV/vis spectroscopy, fluorescence spectroscopy, DSC, and TGA. The films showed a broad emission band from 500-700 nm and were thermally stable up to 200 °C. Using the bismaleimide with a disulfide moiety as the cross-linker, reductive degradation of the films can be induced. Finally, cellulose-tetrazole was cross-linked in a spatially resolved fashion, providing a strategy for the shaping of films based on renewable resources.

Synthesis of cellulose fatty esters as plastics-influence of the degree of substitution and the fatty chain length on mechanical properties

Alternative films: The effect of the chain length and the degree of substitution on the mechanical and hydrophobic properties of various cellulose fatty ester plastic films was studied. The results suggest that the cellulose ester plastic films are promising alternatives to petrochemical commodity plastics such as polyethylene.Cellulose-based plastic films were prepared by acylating cellulose in homogeneous media under microwave irradiation with fatty acyl chlorides containing either saturated or unsaturated chains of various lengths (C(12) to C(18)). The resultant cellulose esters were analysed by FTIR and (1)H NMR spectroscopy to confirm their structure and to determine their degree of substitution. Some of the cellulose fatty esters were then converted into polymer films by casting. The mechanical properties of these films were determined, including their elastic modulus, tensile strength and tensile strain level. The hydrophobicity of the polymer films was determined by contact angle measurement with water. The mechanical and hydrophobic properties of the plastic films were then compared to those of commodity plastics.

Undecylenic acid: a valuable and physiologically active renewable building block from castor oil

A lot of attention is currently being paid to the transition to a biobased economy. In this movement, most efforts concentrate on the development of bioenergy applications including bioethanol, biodiesel, thermochemical conversion of biomass, and others. However, in the energy sector other nonbiomass alternatives are known, whereas no valuable alternatives are available when thinking about chemical building blocks. Therefore, it is also essential to develop new routes for the synthesis of bio-based chemicals and materials derived thereof. Such intermediates can originate either from plants or from animals. Castor oil is a non-edible oil extracted from the seeds of the castor bean plant Ricinus communis (Euphorbiaceae), which grows in tropical and subtropical areas. Globally, around one million tons of castor seeds are produced every year, the leading producing areas being India, PR China, and Brazil.2 10-Undecenoic acid or undecylenic acid is a fatty acid derived from castor oil that, owing to its bifunctional nature, has many possibilities to develop sustainable applications.