An investigation of the thermolysis mechanism of model urethanes

Abstract

The products of pyrolysis in a helium atmosphere of a model urethane foam based on PAPI and propoxylated trimethylol propane were investigated by using GC/MS and GC/CIMS. Chemical‐ionization mass spectrometry was used because it produces primarily protonated molecular ions (M + 1) with little fragmentation which facilitated the identification of the polyol decomposition products. Identification of the polyol pyrolysis fragments has led to the formulation of a detailed polyol thermolysis mechanism. This mechanism shows the polyol to decompose by a systematic route of reactions rather than by a random breakdown.

Development of the Thermal Decomposition Mechanism of Polyether Polyurethane Foam Using Both Condensed and Gas-Phase Release Data

“…Based on the composition, the chemical formula of the virgin foam was determined to be CH 1.53 O 0.27 N 0.08 . This result is in good accordance with various compositions of such polyurethane foam reported by Voorhees et al (1978), Bustamante and compilated in LNE confidential databases.…”

“…Nevertheless, deep different kinetics are observed after T $ 250 C. Indeed, each peak in Figure 3 represents a decomposition reaction (stage) that transforms reactive into particular products according to the atmosphere. Shifts of MLR through high temperatures with increasing b were largely reported by Voorhees et al (1978). The temperatures of MLR peaks for two atmospheres and four heating rates are summarized in Table 3.…”

“…In 2007, were produced only in Western Europe around 1.4 million tons of flexible polyurethane foam similar to the one used in this research. Troitzsch (2004) and Voorhees et al (1978) showed that if PPUF is largely produced worldwide, it is involved in numerous fires, has a high flammability, and its main effluents have high potential toxicity (such as Ammonia, NH 3 ; Nitrogen monoxide, NO; Formaldehyde, H 2 CO; Carbon monoxide, CO; Carbon dioxide, CO 2 ; Hydrogen cyanide, HCN).…”

Synthesis, structure and properties of poly(ether-urethane)s synthesized using a tri-functional oxypropylated glycerol as a polyol

“…The thermal decomposition of urethane bonds was investigated by Dyer et al [35][36][37], who studied the thermal degradation of the model urethanes (i.e., carbamates) and indicated three ways of the urethane linkage cleavage at low temperatures (200-300°C), i.e., (1) dissociation to isocyanate and alcohol, (2) dissociation to primary amine, olefin and carbon dioxide, and (3) elimination of carbon dioxide, leading to formation of a secondary amine. The thermal decomposition of polyurethanes is well described in the scientific literature [38][39][40].…”

Optimization of pyrolysis conditions of polyurethane for recycling of solid products

“…Esperanza and García [3] estimated the activation energy and reaction order from the TGA experimental data. Voorhees et al investigated the thermolysis mechanisms of model urethanes and a specifically labeled deuterated urethane in an inert atmosphere [4,5]. Bilbao et al [6] compared the kinetics of the thermal decomposition of polyurethane foam in different atmospheres.…”