Toxicity Of Pyrolysis Products Research Articles

Pulmonary response to perfluoropolymer fume and particles generated under various exposure conditions

Combustion-product toxicity of perfluorinated polymers in small-scale tests varied markedly under various exposure conditions. The toxicity of perfluoropolymer fumes is associated with submicron pyrolysis particles (0.03–0.15 μm) in the fumes. The toxicity of pyrolysis products was not observed in rats exposed to the fumes filtered to remove the particles. The particles in the fume were agglomerated by aging or a water-treatment process, and the toxicity of particles was markedly reduced when rats were exposed to aged or water-treated fumes. Some agglomerated particles showed chain-aggregation and ultimately attained nonrespirable size. The reduced toxicity of pyrolysis fume is believed to be due to a decreased number of toxic particles resulting from particle agglomeration. Aged particle agglomerate was not toxic when instilled intratracheally into the rats. However, the particle agglomerate became toxic when rats were exposed by the inhalation to fumes evolved from the reheated agglomerate. The fumes contained numerous toxic submicron particles evolved from thermal decomposition of agglomerates by reheating. Rats exposed to the pyrolysis fumes died with pulmonary edema and hemorrhage due to Type I pneymocyte damage. The edematous lungs revealed some agglomerated particles, but it was difficult to distinguish small pyrolysis particles from contaminating dust or cellular debris.

Relative Toxicity of Pyrolysis Products of Some Elastomers

Relative Toxicity of Pyrolysis Products of Some Elastomers

The effect of test conditions on the relative toxicity of the pyrolysis products from some plastics

The authors discuss the differing results obtained from various test methods used to determine the toxicity of pyrolysis products.

Relative Toxicity of Pyrolysis Products From Some Upholstery Fabrics

Twenty-two samples of upholstery fabrics used in home fur nishings were evaluated for relative toxicity by means of the USF/NASA toxicity screening test. This test appears suitable for discriminating be tween these materials, on the basis of time to first sign of incapacitation (Ti) and time to death (Td) under a fixed set of test conditions.

Toxicity of pyrolysis products of vinyl plastics.

Polyvinyl chloride polymers and formulations were pyrolyzed in a stream of air by gradually raising the temperature from ambient to approximately 600 C. The pyrolysis air stream was diluted with twice its volume of room air, and rats were exposed to it. Exposure to an air stream containing the pyrolyzed products of 1 to 2 gm of polyvinyl chloride polymer resulted in the death of 50% of the animals. Most deaths were due to carbon monoxide (CO), and carboxyhemoglobin (COHb) levels correlated well with the amount of plastic pyrolyzed. Little histological evidence of lung damage was evident. When oxygen (O2) was added to the air stream to prevent deaths from CO, pulmonary edema and interstitial hemorrhage developed. The lungs of some animals exposed to high levels of pyrolysis products of vinyl chloride-vinyl acetate copolymer also showed focal edema and intra-alveolar hemorrhage. Polyvinyl chloride formulations, containing additives and inert materials, were in general less toxic per gram of sample pyrolyzed.

The toxicity of polytetrafluoroethylene pyrolysis products including carbonyl fluoride and a reaction product, silicon tetrafluoride.

Abstract The toxicity of pyrolysis products (550°C) of polytetrafluoroethylene (PTFE) was evaluated by exposure of dogs, rabbits, guinea pigs, rats and mice. Carbonyl fluoride (COF2) was identified as the principal toxic component. One-hour exposures of rats showed a 24-hour LC50 of 370 ppm for the pyrolysis products and an LC50 of 360 ppm for COF2. When PTFE is pyrolyzed in the absence of silica, the products are less toxic to a slight degree. Pathology revealed changes in the lungs and livers of exposed animals. Irritation of the lungs may persist for some days.