Polyethylene degradation products

Olah (17a) has also reported the alkylation reactions (at -10 with 1 1 HS03F-SbF5) of n-butane with ethylene to yield 38 weight percent of hexanes and of n utane with propylene to yield 29 weight percent of heptanes. The former reaction has also been reported by Parker (31) at 60 , but the product in this case more nearly resembles polyethylene degradation products. In our work with 10 1 HF-TaF5 at 40 , in a flow system, ethylene (14.1 wt.%) reacted with rv-butane to form 3-methyl-pentane as the initial product of 94% selectivity (Scheme 6, path a). The alternative, i.e., the direct reaction of ethylene with a secondary-butyl cation (path b), can be ruled out since butane does not ionize under these conditions (vide supra). 

A. M. CunUffe and P. T. Williams, Characterisation of products from the recycling of glass fibre reinforced polyester waste by pyrolysis. Fuel, 82, 2223-2230, (2003). J. H. Harker and J. R. Backhurst, Fuel and Energy, Academic Press London, 1981. A. C. Albertson and S. Karlsson, Polyethylene degradation products, In Agricultural and Synthetic Polymers, ACS Symposium Series 433, J. E. Glass and G. Swift (eds), American Chemical Society, Washington DC, 60-64, 1990. 

A series of poly(ester-urethane) urea triblock copolymers have been synthesized and characterized by Wagner et al/ using PCL, polyethylene glycol, and 1,4 diisocyanatobutane with either lysine ethyl ester or putrescine, as the chain extender. These materials have shown the elongation at break from 325% to 560% and tensile strengths from 8 to 20 MPa. Degradation products of this kind of materials did not show any toxicity on cells. 

Anaerobic microbes in the presence of water in the landfill will consume these natural products and produce methane, CO2 and humus. One study reported the average composition of 20 year old refuse to be 33 % paper, 22% ash and 12% wood [18]. Thirty core samples revealed a wide range of degradation and microbial activity that were directly attributed to sample moisture content. Recovered polyethylene degradation was evaluated and determined to be as high as 54 %. 

Pesticides and their degradation products were analyzed in samples taken from two disposal pits located at Iowa State University, Ames, lA. The first was an eight-year-old 30,000 L concrete-lined pit where over 50 kg of more than AO different pesticides had been deposited. The second was a two-year-old 90,000 L polyethylene-lined pit where 150 kg of 24 different pesticides had been deposited. 

The solid state stability of indinavir sulfate has been evaluated under a variety of storage conditions and containers. For materials stored in open dishes or in double polyethylene liners within fiber containers, changes in crystallinity i.e., conversion of the crystalline etlranolate to amorphous material or to a hydrate crystal form) have been detected using XRPD or KF methods [7]. Changes in chemical purity i.e., formation of degradation products) have been detected using GC and HPLC methods... 

Propane as a degradation product of polyethylene (a byproduct in the reaction) was ruled out because ethylene alone under the same conditions does not give any propane. Under similar conditions but under hydrogen pressure, polyethylene reacts quantitatively to form C3 to C6 alkanes, 85% of which are isobutane and isopentane. These results further substantiate the direct alkane alkylation reaction and the intermediacy of the pentacoordinate carbonium ion. Siskin also found that when ethylene was allowed to react with ethane in a flow system, n-butane was obtained as the sole product, indicating that the ethyl cation is alkylating the primary C—H bond through a five-coordinate carbonium ion [Eq. (5.66)]. 

Since the environmental degradation of polyethylene starts with abiotic oxidation, the determination of abiotic oxidation products is an important step towards establishing the environmental degradation mechanisms and environmental impact of the material. In a secondary process, microorganisms may utilise these abiotic degradation products and the low molecular weight... 

Table 2 Low molecular weight degradation products identified in thermo- and photo-oxidised polyethylene ...

Ozonolysis of (—)-a-pinene 146 in pentane at — 35 °C or on polyethylene at —70°C affords only epoxide 147 and its degradation products 148 and 149 but no ozonide, perhaps due to steric hindrance caused by the two geminal methyl groups <1996T14813>. 

Headspace-GC-MS analysis is useful for the determination of volatile compounds in samples that are difficult to analyze by conventional chromatographic means, e.g., when the matrix is too complex or contains substances that seriously interfere with the analysis or even damage the column. Peak area for equilibrium headspace gas chromatography depends on, e.g., sample volume and the partition coefficient of the compound of interest between the gas phase and matrix. The need to include the partition coefficient and thus the sample matrix into the calibration procedure causes serious problems with certain sample types, for which no calibration sample can be prepared. These problems can, however, be handled with multiple headspace extraction (MHE) [118]. Headspace-GC-MS has been used for studying the volatile organic compounds in polymers [119]. The degradation products of starch/polyethylene blends [120] and PHB [121] have also been identified. 

Aging under these conditions is reported to cause hydrolysis of cellulose and produce primarily glucose and xylose as short chain degradation products (12). The aging chamber is described by Kerr et al. (3). Individual specimens were rolled loosely around a glass rod, inserted into a Diehls-Alder pressure test tube (Ace Glass, Inc.) and suspended above one mL of distilled water in the bottom of the tube. Tubes were capped with polyethylene-lined bottle caps, and immersed in an oil bath for 15 days. 

Zitting A, Savolainen H. 1979. Neurotoxic effects of the oxidative thermal degradation products from low density polyethylene. Fire Mater 3 80-83. 

---