Cellulose esters biodegradation

Mohanty et al. [13] evaluated biocomposites formed using chopped hemp fibre and cellulose ester biodegradable plastic. The effect of two different processing approaches was studied. For the first process, the chopped fibre (30% by weight) was mechanically mixed in a kitchen mixer for 30 min followed by compression moulding using a picture-frame mould. The second process involved two steps first an extrusion process yielded pellets of cellulose acetate plastic (CAP) second, the pellets were fed into a twin-screw extruder while chopped hemp fibres were fed into the last zone of the extmder. 

As a result of development work between the Battelle Institute in Frankfurt and a German candle-making company, Aetema, biodegradable cellulose acetate compounds have been available since 1991 from the Rhone-Poulenc subsidiary Tubize Plastics. They are marketed under the trade names Bioceta and Biocellat. The system is centred round the use of an additive which acts both as a plasticiser and a biodegrading agent, causing the cellulose ester to decompose within 6-24 months. 

CELLULOSE ESTERS - ORGANIC ESTERS] (Vol 5) Biodegradable cobuilders... 

Glasser W., McCartney B., Samaranayake G. Cellulose derivatives with low degree of substitution. 3. The biodegradability of cellulose esters using a simple enzyme assay. Biotechnology Progress 10 214-219 (1994). 

Ho, K.-L.G. and Pometto, A.L. Ill (1999) Temperature effects on soil mineralization of polylactic acid plastic in laboratory respirometers. Journal of Environmental Polymer Degradation, 1, 101-108. Buchanan, C.M., Dorschel, D.D., Gardner, R.M. et al. (1995) Biodegradation of cellulose esters Composting of cellulose ester-diluent mixture. Journal of Macromolecular Science, Part A Pure and Applied Chemistry, A32,683-697. 

Cellulose can be reacted with lactones to result in cellulose hydroxy carboxylic acid esters (36). Cellulose can be activated with lye and subsequently reacted with lactones in suspension. There is no need to use cellulose specific solvents. In this way, polymeric cellulose esters with side chains are obtained. The cellulose esters are thermoplastic and biodegradable. 

Modified cellulose of commercial significance involves primarily the cellulose esters and ethers. The cellulose esters include cellulose acetate, cellulose propionate, cellulose acetate-butyrate, cellulose nitrate. Cellulose ethers include ethyl cellulose as a melt, processable-grade and water-soluble derivatives. Historically, it was accepted that cellulose derivatives that had a degree of substitution above 1.0 were not biodegradable [18-20]. However, cellulose acetate has been found to be biodegradable in both aerobic compost and anaerobic bioreactor environments [21-23]. The potential for additional, biodegradable, cellulose derivatives is currently being explored. 

Edgar et al. (2001) have focused on the performance of cellulose esters in modern coatings, controlled release of actives, plastics (with particular focus on biodegradable plastics), composites and laminates, optical films, and membranes and related separation media [29]. 

Several water-soluble polymers are known which are stable in the solid state but will biodegrade once they are dissolved. These include both synthetic and natural polymers, such as polyvinyl alcohol, cellulose esters and ethers, acrylic acid polymers, polyacrylamides, and... 

Phase behaviour and erystallisation kinetics for the binaiy blend P(3HB)/ eellulose propionate (CP) were performed by Maekawa et Cellulose aeetate butyrate (CAB), which has a combination of high (160 °C) and Tg (113 °C), is an important thermoplastic cellulose ester that can biodegrade in a natural environment. In an attempt to make the best use of degradable polyester P(3HB), Wang et al. blended P(3HB) with CAB and studied the relationship between the blend morphology and its physieal properties. 

Materials such as metal, plastic, wood, paper, and leather are coated with pofymers primarily for protection and for the improvement of their properties. For this purpose, cellulose acetate (CA), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB) are the most important classical and solvent-based cellulose esters of the coating industry [44]. Cellulose esters are widely used in composites and laminates as binder, filler, and laminate %ers. In combination with natural fibres, they can be used to some extent as composites from sustainable raw materials with good biodegradability. An additional domain of cellulose esters is their use in controlled-release systems, as well as membranes and other separation media [44, 47]. In the field of controlled-release systems, eellulose esters are used as enteric coatings, hydro-phobic matrices, and semipermeable membranes for appheations in pharmacy, agriculture, and cosmetics. 

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