ISSN:
0021-8995
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
In model experiments based on aerated cultures of molds like Fusarium redolens, 14C liberated from randomly labeled pulverized high-density linear polyethylene (HPDE) with a specific surface of 10 m2/g appeared mainly in the form of respiratory 14CO2. The quantity liberated in this case was slightly greater than that stemming from HDPE film, according to our previous report (0.56% by weight against less than 0.40%). Contaminations could be detected, especially after two years aeration in several culture jars. Two unidentified bacterial strains as well as Acremonium kiliense, Aspergillus versicolor, and Verticillium lecanii were all thriving on the sparse media and enhanced to some extent the degradative 14CO2 liberation, especially in mixed cultures together with F. redolens. Repeatedly close coincidence in 14CO2 development between experiments with somewhat shifting mixed microbial populations point to preference for test with mixed microbial cultures instead of one single pure culture. Such tests should, however, be based on species more likely to utilize hydrocarbons then the celluloses metabolizers often applied for test of plastics according to several internationally accepted prescriptions. Increased liberation of 14CO2 with decreasing particle size indicate that the accessibility of the metabolizable fractions of polyethylene must affect the degree of biodegradation. This is because with an increased surface/volume ratio in the plastic powders of decreasing mesh, more and more structurally hidden low molecular polyethylene material can be released and thus rendered accessible to the enzymes of attacking fungal hyphae. Also the possibility of an increased autooxidative scission of some of the long polymeric chains due to a “mastication effect,” as well as an autocatalytic type of oxidative deterioration caused by remnants of the silico-alumina supported CrO3 primary polymer catalyst must be considered in this connection, especially with regard to the general phenomenon of abiotic aging in the dark which was consistently registered by us.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/app.1978.070221208
Permalink