Methods for Assessment of Biodegradability of Plastic Films in Soil

Abstract

Traditional and novel techniques were tested and compared for their usefulness in evaluating biodegradability claims made for newly formulated "degradable" plastic film products. Photosensitized polyethylene (PE), starch-PE, extensively plasticized polyvinyl chloride (PVC), and polypropylene (PP) films were incorporated into aerobic soil. Biodegradation was measured for 3 months under generally favorable conditions. Carbon dioxide evolution, residual weight recovery, and loss of tensile strength measurements were supplemented, for some films, by gas chromatographic measurements of plasticizer loss and gel permeation chromatographic (GPC) measurement of polymer molecular size distribution. Six-and 12-week sunlight exposures of photosensitized PE films resulted in extensive photochemical damage that failed to promote subsequent mineralization in soil. An 8% starch-PE film and the plasticized PVC film evolved significant amounts of CO2 in biodegradation tests and lost residual weight and tensile strength, but GPC measurements demonstrated that all these changes were confined to the additives and the PE and PVC polymers were not degraded. Carbon dioxide evolution was found to be a useful screening tool for plastic film biodegradation, but for films with additives, polymer biodegradation needs to be confirmed by GPC. Photochemical cross-linking of polymer strands reduces solubility and may interfere with GPC measurements of polymer degradation.

High-density polyethylene (HDPE)-degrading potential bacteria from marine ecosystem of Gulf of Mannar, India

“…(1998) in which they have documented the degradation of thermooxidized LDPE only after 3·5 years of incubation with Arthrobacter paraffineus , whereas the identified strain was able to degrade HDPE in 30 days. The biodegradation of HDPE level is higher in present study compared to the values ranging from 3·5 to 8·4% of previous reports of polyethylene incubated in the soil for 10 years (Potts 1978; Albertsson and Karlsson 1990; Yabannavar and Bartha 1994). The synthetic polyethylene degradation was very slow process according to Otake et al.…”

Preparation and characterization of PVC/montmorillonite nanocomposites—A review

“…Poly(vinyl chloride) for biomedical products such as storage bags or endotracheal tubes is surface-modified by using biodegradable polymers, for example, poly(ethylene glycol) [129,130] or cellulose [131,132], to improve biocompatibility. However, biodegradation of plasticized PVC occurs predominantly because of the presence of plasticizer, and the PVC matrix is less affected by the action of microorganisms [132,133].…”

Improvement of the physico‐mechanical properties and stability of waste polypropylene in the presence of wood flour and (maleic anhydride)‐grafted polypropylene

“…The temperature dependence of storage modulus E 0 and loss tangent (tan @) was measured from 35 to 130 o C with a heating rate of 10 o C/min. [23].…”