Richard Gattin

Biodegradation study of a starch and poly(lactic acid) co-extruded material in liquid, composting and inert mineral media

Abstract The biodegradation of a co-extruded starch/poly(lactic acid) polymeric film was studied in liquid, inert solid and composting media. Main mechanical properties of this film were Youngs modulus: 2340 MPa , elongation at break: 50%, contact angle: 118°. Mineralization of the materials carbon content was followed using the appropriate experimental methods of the International Standard Organisation. Whatever be the biodegradation medium used, the percentage of mineralization was better than the required 60% value for the definition of a biodegradable material. Moreover, repartitioning of the materials carbon between the various degradation products produced was quantified throughout the duration of experimental runs. The presence of starch was found to facilitate biodegradation of the polylactic component, especially in liquid media.

Structural investigation and thermal stability of new extruded wheat flour based polymeric materials.

In this study, we compare physical properties of wheat starch and wheat-flour based materials. The comparison has been done using thermogravimetric, calorimetric, X-ray diffraction, mechanic and morphologic experiments conducted on a series of wheat-flour extruded materials. The wheat flour used here can be understood as a by-product of the farm-produce wheat flour. All data obtained by means of these experimental methods allow us to conclude that, basically no significant difference exists between our wheat-flour based and wheat-starch based materials. Only one clear difference occurs for the strain to break value which decreases by about 30% for wheat-flour based materials.

Comparative Biodegradation Study of Starch- and Polylactic Acid-Based Materials

The degradation of starch- and polylactic acid-based plastic films by microorganisms extracted from compost was studied in a liquid medium. The various degradation products produced were measured throughout the duration of the experiment, and total carbon balances were estimated. For an easily biodegradable material, the evolution of the way carbon repartitioned between different degradation products was quite similar whatever the experimental condition or the type of substrate. On the other hand, for a resistant material exposed to these microorganisms, the nature of the biodegradation depended strongly on the experimental conditions. In the latter case, a differential scanning calorimetry analysis confirmed the importance of the applied norm on the state of the residual material. The consequences for improved methods of estimation of biodegradability of these materials are discussed.

Comparison of mineralization of starch in liquid, inert solid and compost media according to ASTM and CEN norms for the composting of packaging materials

Mineralization percentages of ground starch-based films are similar (68–72%), whatever the degradation medium and the norm used, with standard deviations less than 8%. Vermiculite, an inert solid medium, shows an intermediary behaviour, between liquid and compost media. Consequently, this support is suitable for further degradation studies, including the determination of carbon balances.

Effect of mercerization of flax fibers on wheat flour/flax fiber biocomposite with respect to thermal and tensile properties

New composites materials, 100% ecofriendly based on modified wheat flour as matrix and flax fiber as fillers have been obtained by means of an extrusion process. The wheat flour matrix contains non-toxic plasticizers and is mixed well with natural fibers. One sample series without specific fiber surface treatment and a second series with a mercerization surface treatment have been prepared. The content of fillers varies from 0% w/w to 20% w/w. In this work the performances of these new composites in term of thermal stability, mechanical behaviours are compared and discussed in regard to the fiber treatment efficiency and composition. We observe an interesting behaviour: the efficiency is found the best for a fiber composition close to 10% w/w.

Properties and Biodegradation Nature of Thermoplastic Starch

For the last few decades, the usage of plastic increased because of its specific properties such as low cost, light weight, high strength, non-biodegradability, durability, non corrosive nature, process ability and high energy effectiveness. Hence these plastics can be used for various application which includes household articles to aeronautic sector. Now a day it’s difficult to imagine a life without plastic which are mostly derived from crude oils and natural gas. Among the various polymers, polyethylene, polypropylene and polystyrene are used greatly for food packaging, biomedical field and in agriculture. According to statistics, from 1950 onwards, 9% of growth can be seen globally, in the production and consumption of plastics. In 1950 the overall production of plastic was 1.5 million tones while it reached 245 million tones in 2008.