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Biodegradation of polyethylene
September 1995
Biodegradation
Additivesfor Polymers
of polyethylene
The biodegradability of thermally oxidized polyethylene (PE) has been studied in various conditions: (1) on solid agar in the presence of a suspension of mixed spores of four fungi; (2) in three composting units differing in temperature, moisture content and the nature of the composted materials; and (3) in liquid medium (respirometric flasks) in the presence of three streptomyces strains or of a suspension of microorganisms from compost. Qualitative evidence of bioassimilation of the oxidized PE films was obtained with fungi and in composts. Coverage of the film surface by fungi increases as the molecular weight of the PE is decreased and attains 60% when the initial M lies between 1500 and 600. With fungi and in compost, important surface erosion was delected by SEM for samples with initial M, around 1000. Important changes were also observed by FTIR, DSC and GPC. This last method revealed in all cases rhe formatjim of a high molecular weight fraction that was not present before incubation with microorganisms and a shift of the whole curve toward higher molecular weight. This is evidence of chain condensation probably due lo pflrely thermal reaction at the low partial pressure of O2 prevailing in the industrial composting units used in this work. It is probably accompanied by bioassimilation of the low molecular wejght fraction. Quantitative information can be obtained by a method. incubations respirometric For performed in liquid medium in the presence of a suspension of microorganisms frvm compost, biodegradation was important when substrate concentration was very low. Despite the presence of unavoidable large errors in these conditions, oxygen uptake was evident and biodegradation of the low mo\ecular weight fraction of the sample was clearly demonstrated. (25 refs). Polymer Degradation & Stability, 1995, (2), 275-289
01995 Elsevier Science Ltd
COMPANY
IUEWS
Air Products acquires Akzo epoxy curing agents Akzo Nobel of Arnhem and Air Products and Chemicals Inc, of Allentown, Pennsylvania, USA, have signed an agreement on the divestment of Akzo Nobel’s epoxy curing agents and adhesion promoters business. The transaction includes several high-performance, water-based curing agents which complement Air Products’ portfolio in this area. Contact: Akzo Nobel nv, Velperweg 76, PO Box 9300, 6800 SB Arnhem, The Netherlands. Tel: f 31-85-66-4343. Fax: + 31-85-66-4940.
ENVIRONMENTAL ISSUES New procedures required for regulating indirect food additives The Food and Drug Administration’s (FDA) current regulation on indirect food additives has become a burden on indusny and government, and should be replaced by an entirely new system, according to the Society of The Plastics Industry Inc (SPI). Currently, indirect additives for food use, such as in packaging, are subject to the same rulemaking process as direct food additives, even though indirect additives may not migrate into foods, or may do SO in infinitesimal and harmless amounts. The SPI says that separate statutory treatment for packaging is merited because the use and potential for ingestion of these substances differ dramatically from substances directly and deiitirately added to food. The SPI suggests that the FDA a premarket notification plan permit any company to submit about food packaging materials
should adopt that would information to the FDA
9
Biodegradation
Additivesfor Polymers
of polyethylene
The biodegradability of thermally oxidized polyethylene (PE) has been studied in various conditions: (1) on solid agar in the presence of a suspension of mixed spores of four fungi; (2) in three composting units differing in temperature, moisture content and the nature of the composted materials; and (3) in liquid medium (respirometric flasks) in the presence of three streptomyces strains or of a suspension of microorganisms from compost. Qualitative evidence of bioassimilation of the oxidized PE films was obtained with fungi and in composts. Coverage of the film surface by fungi increases as the molecular weight of the PE is decreased and attains 60% when the initial M lies between 1500 and 600. With fungi and in compost, important surface erosion was delected by SEM for samples with initial M, around 1000. Important changes were also observed by FTIR, DSC and GPC. This last method revealed in all cases rhe formatjim of a high molecular weight fraction that was not present before incubation with microorganisms and a shift of the whole curve toward higher molecular weight. This is evidence of chain condensation probably due lo pflrely thermal reaction at the low partial pressure of O2 prevailing in the industrial composting units used in this work. It is probably accompanied by bioassimilation of the low molecular wejght fraction. Quantitative information can be obtained by a method. incubations respirometric For performed in liquid medium in the presence of a suspension of microorganisms frvm compost, biodegradation was important when substrate concentration was very low. Despite the presence of unavoidable large errors in these conditions, oxygen uptake was evident and biodegradation of the low mo\ecular weight fraction of the sample was clearly demonstrated. (25 refs). Polymer Degradation & Stability, 1995, (2), 275-289
01995 Elsevier Science Ltd
COMPANY
IUEWS
Air Products acquires Akzo epoxy curing agents Akzo Nobel of Arnhem and Air Products and Chemicals Inc, of Allentown, Pennsylvania, USA, have signed an agreement on the divestment of Akzo Nobel’s epoxy curing agents and adhesion promoters business. The transaction includes several high-performance, water-based curing agents which complement Air Products’ portfolio in this area. Contact: Akzo Nobel nv, Velperweg 76, PO Box 9300, 6800 SB Arnhem, The Netherlands. Tel: f 31-85-66-4343. Fax: + 31-85-66-4940.
ENVIRONMENTAL ISSUES New procedures required for regulating indirect food additives The Food and Drug Administration’s (FDA) current regulation on indirect food additives has become a burden on indusny and government, and should be replaced by an entirely new system, according to the Society of The Plastics Industry Inc (SPI). Currently, indirect additives for food use, such as in packaging, are subject to the same rulemaking process as direct food additives, even though indirect additives may not migrate into foods, or may do SO in infinitesimal and harmless amounts. The SPI says that separate statutory treatment for packaging is merited because the use and potential for ingestion of these substances differ dramatically from substances directly and deiitirately added to food. The SPI suggests that the FDA a premarket notification plan permit any company to submit about food packaging materials
should adopt that would information to the FDA
9