Biological degradation of plastics: a comprehensive review.

Plastic waste is currently generated at a rate approaching 400 Mt year–1. The amount of plastics accumulating in the environment is growing rapidly, yet our understanding of its persistence is very...

Degradation Rates of Plastics in the Environment

Plastics in soil: Analytical methods and possible sources

Polyethylene (PE) has been considered nonbiodegradable for decades. Although the biodegradation of PE by bacterial cultures has been occasionally described, valid evidence of PE biodegradation has remained limited in the literature. We found that waxworms, or Indian mealmoths (the larvae of Plodia interpunctella), were capable of chewing and eating PE films. Two bacterial strains capable of degrading PE were isolated from this worm’s gut, Enterobacter asburiae YT1 and Bacillus sp. YP1. Over a 28-day incubation period of the two strains on PE films, viable biofilms formed, and the PE films’ hydrophobicity decreased. Obvious damage, including pits and cavities (0.3–0.4 μm in depth), was observed on the surfaces of the PE films using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The formation of carbonyl groups was verified using X-ray photoelectron spectroscopy (XPS) and microattenuated total reflectance/Fourier transform infrared (micro-ATR/FTIR) imaging microscope. Suspension cultu...

Evidence of polyethylene biodegradation by bacterial strains from the guts of plastic-eating waxworms.

Recent trends in biodegradable polymers indicate significant developments in terms of novel design strategies and engineering to provide advanced polymers with comparably good performance. However, there are several inadequacies in terms of either technology or cost of production especially in the case of applications in environmental pollution. So, there is a need to have a fresh perspective on the design, properties and functions of these polymers with a view to developing strategies for future developments. The paper reviews the present state-of-art on biodegradable polymers and discusses the salient features of the design and properties of biodegradable polymers. Special emphasis is given to the problems and prospects of (1) approaches adopted to make non-biodegradable synthetic polymers such as polyethylene biodegradable and (2) biodegradable polymers and copolymers made from renewable resources especially poly(lactic acid) based polymers and copolymers which are emerging as the candidate biodegradable materials for the future.

Biodegradable Polymers- A Review on Recent Trends and Emerging Perspectives

The biodegradation of several polymers that had been buried under soil for over 32 years was examined. No evidence of biodegradation was found for polystyrene, polyvinylchloride, and urea formaldehyde resin. A remarkable degradation was indicated for low density polyethylene thin films which were directly in contact with soil. Severely degraded parts of the film is characterized by whitening. Many small holes were recognized on the surface of the whitened part. The whitened part is specific for the growth of hyphae. FT-IR spectra of the whitened part showed a characteristic band in the vicinity of 1640 cm−1 which was assigned to the stretching vibration of CC bond. Although the part which was not in contact with soil was clear, it also showed evidence of degradation from the presence of carbonyl band in FT-IR. It was suggested that the degradation of the clear part is due to the usual thermo-oxidative process, while the degradation of the whitened part is due to the biotic process. © 1995 John Wiley & Sons, Inc.

Biodegradation of low-density polyethylene, polystyrene, polyvinyl chloride, and urea formaldehyde resin buried under soil for over 32 years

PURPOSE: To provide a new biodegradable resin composition favorably biodegraded by burying in soil, crude rubber, compost or the like. CONSTITUTION: This composition comprises a thermoplastic resin, lignin, an animal oil, a vegetable oil or an oxidized oil thereof and a metallic compound selected from the group consisting of a metal salt, a metal oxide and a metal hydroxide. COPYRIGHT: (C)1995,JPO

Biodegradable resin composition

PURPOSE: To enable the substential biodegradation of a coating material at the time when a delayed release fertilizer loses its effect by coating the fertilizer with a biodegradable plastic obtained by blending starch or its modified material and an organometallic compound with a base polymer CONSTITUTION: Biodegradable plastics are prepared by blending starch or a modified starch obtained by grafting a polymerizable monomer such as styrene or that coated with silicon, etc, with a thermoplastic resin or a mixture of one or more kinds of thermoplastic resin, preferably an ethylene-vinyl acetate copolymer and/or a low-density polyethylene and at least one kind of the salt, oxide, hydroxide or organometallic compound of a metal selected from Fe, Al, K, Ca, Mg, Zn, Mn, etc Then, fertilizer in an arbitrary form of granules, balls or cylinders is coated with the biodegradable plastic to give the objective resin-coated delayed release fertilizer COPYRIGHT: (C)1996,JPO

Fertilizer coated with resin

PURPOSE:To obtain a biodegradable resin composition having an accelerated biodegradability when buried in soil, garbage, compost, etc., by kneading a thermoplastic resin with oils, etc., and an organic peroxide compound. CONSTITUTION:This composition is obtained by kneading (A) a thermoplastic resin (preferably polyethylene) with (B) an oil and/or an oxidized oil, (C) an organic peroxide [preferably dicumyl peroxide, alpha, alpha'-bis(t-butylperoxy-m- isopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane or 2,5-dimethyl-2,5-di(t- butylperoxy)hexyne-3] and optionally (D) starch and/or a modified starch, (E) a metal salt, a metal oxide or a metal hydroxide and (F) an oxidized wax, at a temperature higher than the softening temperature of the resin A.

Production of biodegradable resin composition

PROBLEM TO BE SOLVED: To provide a filter medium for air filters and a filter unit which have dust-collecting power comparable with that of current filter media and can reduce problems associated with disposal and be manufactured easily. SOLUTION: The filter medium 10 for air filters has the first web 14 composed of a biodegradable synthetic fiber 12 of an average fineness of 3.3-33 decitexes and the second web 18 which contains at least 50 wt.% of a biodegradable synthetic fiber 16 having a modified cross-section and has an average fineness of 1-6 decitexes. The first web 14 and the second web 18 overlie in an integrated form by a mechanical entangling method and adhered with a biodegradable binder 20. COPYRIGHT: (C)2007,JPO&INPIT

Otake Yoshito

Papers

Biodegradation of low-density polyethylene, polystyrene, polyvinyl chloride, and urea formaldehyde resin buried under soil for over 32 years

Biodegradable resin composition

Fertilizer coated with resin

Production of biodegradable resin composition

Filter medium for air filter and filter unit