LLDPE pyrolysis

LLDPE can present a certain health hazard when it bums, since smoke, fumes, and toxic decomposition products are sometimes formed in the process. Exposure to burning LLDPE can cause irritation of the skin, eyes, and mucous membranes of the nose and throat due to the presence of acrolein and formaldehyde (81). Toxicity of LLDPE pyrolysis products depends on temperature, heating rate, and the sample size (82—84). 

CHEMICALS AND ENERGY FROM MEDICAL POLYMER WASTES. II. MALEATED PYROLYSIS PRODUCTS IN IPP/LLDPE PROCESSING... 

Details are given of ways of obtaining energy from the pyrolysis of disposable syringes. The waxy product was chemically modified with maleic anhydride and tested in the processing of PP/LLDPE blends in a rheometer or twin-screw extruder. Compatibility of components in binary or ternary blends and DSC results are discussed. 35 refs. 

Nonvolatile compounds cannot be analysed unless pyrolysis or derivatisation converts them to a condition amenable to GC. Derivatisation GC (or LC) has been used for several components such as erucamide (imidi-sation for volatility), fatty amines (aromatic amidation for UV detectability), and polyethylene oxides (esterification for both volatility and detectability) [178]. The surface concentration of erucamide on extruded LLDPE films was determined quantitatively by surface washings with ether, followed by evaporation, dissolution... 

When pyrolysis is carried out at 150 °C the components occurring at the maximum concentration in the hydrocarbon region are located in the C23 region for virgin linear low-density polyethylene (LLLDPE), LDPE - 50% magnesium hydroxide and LLDPE - 40% magnesium hydroxide - 10% red phosphorus. 

A brief review is presented on techniques for the analysis of polyolefins and additives in polyolefins. Techniques considered include high-temperature GPC combined with FTIR spectroscopy for the analysis of chemical composition as a function of molar mass, crystallisation fiactionation for the analysis of short-chain branching in LLDPE and of polyolefin blends and pyrolysis-gas chromatography-mass spectrometry for the determination of additives, such as antioxidants, in polyolefins. 13 refs. (3rd Annual UNESCO School lUPAC Conference on Macromolecules and Materials Science, Stellenbosch, South Africa, 2000)... 

A forensic sample consisting of melt-recrystallised polymers recovered from the scene of a fire in a factory is identified by differential scanning calorimetry. The factory commonly used two kinds of film sheets, A and B, made by different manufacturers. It is necessary to decide whether the forensic sample related to material A or B. The forensic sample and reference samples of materials A and B are subjected to IR spectroscopy and pyrolysis gas chromatograph mass spectrometry measurements, which reveal their PE nature. The thermal behaviour of the samples is examined by differential scanning calorimetry (DSC) and they are found to be blends of two kinds of PEs, LDPE and LLDPE. The samples can be identified and distinguished from each other via the DSC measurements. 6 refs. 

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