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International audience; Agricultural wastes such as olive pomace and barley bran have been transformed in plastic by esterification with fatty acid chlorides after acidic or alkaline delignification. These esterifications were carried out in homogenous solution DMA/LiCl by classical heating or microwave activation. The plastics obtained were characterized by IR and NMR spectra, and tested for their mechanical properties and potentiality of biodegradation. The mechanical properties were improved by olefin metathesis of undecylenic ester from olive cellulose. delignification.

This work deals with the synthesis of cellulosic plastic films obtained in homogeneous conditions by microwave-induced acylation of commercial or chestnut tree sawdust cellulose by fatty acids. The acylation reaction was studied according to N,N-dimethyl-4-aminopyridine (DMAP) amount, DMAP simultaneously playing the role of catalyst and proton trapping base. This study clearly showed that DMAP does not influence degrees of substitution (DS), massic, and molar yields. Plastic films synthesized in the absence of DMAP showed a decrease in mechanical behavior. Organic (tributylamine) or inorganic bases (CaCO3, Na2CO3) were then added to replace DMAP basic activity, and no changes were observed. Concerning thermal and mechanical properties of plastics obtained with various bases, glass transition temperatures (Tg) and degradation temperature (Td) were found constant whatever the base, and the best mechanical properties were obtained for films synthesized in the presence of CaCO3. The same remarks were made concerning the valorization of chestnut tree sawdust cellulose. Microbial biodegradation of plastic films with DS = 2.2 led to a loss of their mechanical behaviors. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1266–1278, 2005

Cellulose-enriched residues from maize bran can be transformed into plastic films after esterification of the cellulose by various fatty acid chlorides. Alkali pretreatment and acidic activation of the sample are necessary before the esterification reaction in order to form esters. The degradation by microorganisms of the plastic film was also studied. We showed that the isolated strain (chromobacterium violaceum) can hydrolyze modified cellulose plastic films. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 3040–3045, 1999

Cellulose-enriched residues from wheat bran can be transformed in bioplastics after esterification of the cellulose by lauroyl chloride. Before the esterification reaction, an activation step with a swelling of the sample in dilute acid and subsequent drying was required. This activation had a marked influence on the amount of esterified product and its degree of substitution. Using pure cellulose as well as cellulose-enriched agricultural residues, we have shown that the cellulose was totally recovered after this pretreatment and that partial hydrolysis of cellulose chains occurred during the drying step, which probably improved the accessibility to chemical reagents. The possible role of sulfuric acid as catalyst for the esterification reaction of the cellulose by lauroyl chloride was discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1933–1940, 1999

Two agricultural by-products, sugar-beet pulp and wheat bran, have been examined for their suitability to be transformed into bioplastics by esterification by lauroyl chloride. Influence of cellulose content was studied on eleven samples enriched in cellulose after chemical or enzymatic removal of pectins from sugar-beet pulp and heteroxylans from wheat bran. After a pretreatment by immersion in 0.5 mol/L sulfuric acid, esterification was carried out with lauroyl chloride. Neither the amount of cellulose nor the extraction treatment had a marked influence on the formation of plastic. A film could be obtained from all the wheat-bran samples, including samples with low cellulose content, but only from one sugar-beet pulp sample. The crystallinity of the cellulose in sugar-beet pulp and wheat bran were different. The nature of cellulose could be responsible for the failure of sugar-beet pulp residues to form plastic.