Toxicity of products of thermal oxidative degradation of nitrogen-containing building polymer materials

Abstract

Introduction. In the event of fires in residential premises in which nitrogen-containing thermal insulation materials (foam rubber, polyisocyanurate foam) are used, the victims will be exposed to toxic thermal degradation products. Data on long-term disorders caused by intoxication by thermal degradation products of these materials could not be found in the available literature. The aim of the study was to assess the toxicity of the products of thermal oxidative degradation of nitrogen-containing thermal insulation materials, both in the early and long-term post-intoxication period. 
 Material and methods. Static inhalation intoxication of rats with products of thermooxidative destruction of polyfoam and polyisocyanurate foam (at a concentration of 0,8HLC50) was simulated. The concentration of carboxyhemoglobin in the blood of rats, indicators of vital functions were determined immediately before and on days 1, 7 and 28 after exposure. To assess learning disabilities in rats, a conditioned reflex of active avoidance by swimming was developed. To assess spatial memory in rats, the method of developing and reproducing the conditioned reflex of searching for food was used.
 Results and discussion. The intoxication of rats with products of thermooxidative destruction of the studied materials of moderate severity was simulated. Violations of the functions of the respiratory and cardiovascular system of rats in the early (7 days) and long-term (28 days) post-intoxication period were not detected. In the long-term (28 days) post-intoxication period, an increase in the duration of the latent period of active avoidance by swimming of rats was determined (compared with the control), an increase in the number of spatial memory errors in rats and the time of testing (compared with the control) was revealed.
 Limitation of the study. Limitations are due to the methodology of the research being conducted. A quantitative analysis of only some gaseous products of thermal oxidative destruction was perfomed.
 Conclusion. It was found that intoxication of rats with products of thermooxidative destruction of foam rubber and foam polyiysocyanurate (at a concentration of 0,8HLC50) led to impaired learning and spatial memory of rats in the long-term post-intoxication period.