Packaging partially biodegradable

Polymer blends, particularly olefins with biodegradable polymers, are gaining popularity as an approach to degradable packaging plastics. The materials are at best only partially biodegraded, but will lose form and bulk as the plastic disintegrates. This may be sufficient in landfill as volume diminishes, leaving room... 

ARV 99] Arvanitoyannis I.S., Totally and partially biodegradable polymer blends based on natural and synthetic macromolecules preparation, physical properties, and potential as food packaging materials , Journal of Macromolecular Science - Reviews in Macromolecular Chemistry Physics, vol. C39, no. 2, pp. 205-271, 1999. 

If starch is modified by partially fermenting it, or esterifying or etherification, the resulting material can be extruded by adding plasticizers. Starch-based plastics are readily biodegraded. In most cases, the polymers are also water-soluble. Several suppliers now offer thermoplastic starch. Major markets include soluble films for industrial packaging, films for bags and sacks, and loose fill. 

An improvement in terms of flexibility for PLA may widen its application as a biodegradable packaging and film material. The addition of plasticizers has been investigated lately in order to improve the fragility and increase the elongation of break or elasticity of PLA. Previous researchers have shown that addition of plasticizers such as polyethylene glycol (PEG), glucosemonoesters and partial fatty acid esters had successfully overcome the brittleness and widen PLA s application [2, 7, 8]. 

PCL -OCH CH CH CH CH CO-ln) is a partially-crystalline polyester that is biodegraded by microbial lipases and esterases. The plastic is made from petrochemical feedstocks. It has too low a melting point (60°C) to be useful in any packaging applications. Higher aliphatic polyesters such as poly(butylene succinate) (PBS) (-0(CH2) OC(CH2)2CO-)n and poly(ethylene succinate) (PES) (-OCCH l OOCCCH l CO-) are also biodegradable at a rate that depends on environmental factors (Kasuya et al., 1997). They have higher melting points of 112-114°C and 103-106°C, respectively, and the properties compare well to those of polyolefins. As succinic acid can be derived from plant sources, the polysuccinates can be potentially a bio-based polymer. 

Therefore, there is a considerable interest in replacing some or all of the synthetic plastics by natural or biodegradable materials in many applications. Since the food industry uses many plastics, even a small reduction in the amount of materials used for each package would result in a significant polymer reduction, and may improve solid waste problems [10]. It is clear that the use of biodegradable polymers for packaging offers an alternative and partial solution to the problem of gathering of solid waste composed of synthetic inert polymers [11]. 

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