Volatiles release from photo-degrading, pigmented PVC : Kinetic changes

Volatile species produced during the ultraviolet irradiation of a rigid, poly(vinyl chloride) construction panel have been established as a function of irradiation time. Residual organic and chloroorganic compounds were detected in the polymer surface after irradiation. Similar species are also directly released during irradiation. In both cases, these were identifed and quantifed by gas chromatography, with mass spectrometry detection. Rates of volatilisation of organic and chloroorganic compounds were measured directly during accelerated exposure conditions and dropped sharply with irradiation time. This drop may be attribu- table to the cross-linking of the irradiated surface which becomes chlorine def- cient and rich in titanium dioxide pigment (rutile). In contrast, samples exposed to sunlight did not undergo surface cross-linking but did thermally desorb vola- tiles similar to laboratory exposed samples.Peer reviewed: YesNRC publication: Ye

Environmental management

NRC publication: Ye

The role of feed composition on the composting process. I. Effect on composting activity

Peer reviewed: YesNRC publication: Ye

The role of feed composition on the composting process. II. Effect on the release of volatile organic compounds and odours

In this study the influence of four specific feed materials: grass clippings, leaves, cabbage and soya bean meal on odours and VOCs has been studied in a controlled and systematic manner using a commercial feed material in laboratory composters. The results of this study suggest that while some feeds can be composted with the minimum of problems, high levels of specific feeds could be problematic. Based upon the results obtained with the four feeds examined the following general observation can be made: Grass can be satisfactorily incorporated into compost feed at levels up to about 10% without adversely effecting odour emissions or VOC releases. At higher grass levels odours could start to become a problem. High levels of leaves, up to at least 30%, appear to have no detrimental impact on odours or VOC releases. While low levels of cabbage may be acceptable (less than 10%), higher levels can give rise to high emissions of sulphur compounds and result in serious odour problems. It appears that high nitrogen containing materials, when present in large amounts, can lead to serious odour problems associated with anaerobic activity. The presence of ammonia in the VOCs is a clear indication of excessive levels of nitrogen in the compost feed.Peer reviewed: YesNRC publication: Ye

Analyses of volatile transformation products from additives in gamma-irradiated polyethylene packaging

Peer reviewed: YesNRC publication: Ye

Phosphite additives and their transformation proudcts in polyethylene packaging for gamma-irradiation

NRC publication: Ye

An investigation of the chemical and physical changes occurring during commercial composting

In this study, the chemical and physical changes in the composting material, along with the emissions of volatile compounds, have been monitored during a 49 day composting period in a commercial composting operation. In addition, samples of composting material, taken from the commercial operation, have been monitored in automated laboratory scale composters. The measurements conducted on the solid samples included: pH, volatile matter, bulk density, air voids, carbon, hydrogen and nitrogen. In addition, the gaseous volatiles were monitored for odor, as well as gas composition as determined by gas chromatography/mass spectrometry. The results clearly indicated that while the behavior of the composting material was different in the laboratory scale unit, in comparison to what was observed in a commercial composting operation, the laboratory method gave valuable information on the compostability of the material, unobtainable in the larger unit. Based upon an evaluation of the physical and chemical parameters measured, a great deal of information was obtained regarding the progression of the composting process and the identification of possible problem areas where biological activity may have been compromised.Peer reviewed: YesNRC publication: Ye