Thermal behaviour of rigid polyurethane foams

Abstract

By means of a combined thermal analysis technique,, the thermal behaviour of rigid polyurethane foams containing additive antipyrenes was studied. The presence of phosphorus-and phosphorus/chlorine-containing antipyrenes based on phosphate and phosphonate and a combination of them led to decreases in the rates of heat and weight loss during heating. More steps of decomposition were formed and the interval of decomposition was widened and shifted to higher temperatures. Some thermal characteristics make it possible to predict the optimum antipyrene compositions and concentrations with minimum time, labour and material consumption under laboratory conditions. Rigid polyurethane foam (RPUF) is an organic material with a high tendency to burn. Its combustibility depends essentially on the thermal stability of the structural chemical bonds and the products of decomposition. As with other types of polyurethanes, its flammability is reduced by the addition of antipyrenes. The problem of selecting optimum antipyrene compositions for polymers is becoming an urgent necessity. It requires the development of laboratory methods which are minimum time-, labour-and material-consuming and can provide maximum insight into the inhibiting effect of antipyrenes, thereby allowing a comparative evaluation of their efficiency. A major shortcoming of the available flammability tests is their failure to meet these requirements. Directly proportional relationships between polymer flammability tests and thermal analysis data have, recently been found [1][2][3][4][5]. Systematic studies [6][7][8][9] in this field, however, are still scarce.The aim of this work was to study the effect of additive antipyrenes with different compositions and structures on the mechanism and kinetics of the total thermal decomposition reactions of RPUF, and the possibility of evaluating their effectiveness as combustion inhibitors.

Thermal behaviour of rigid polyurethane foams

“…The latter decomposes in two stages in the interval from 230 to 670 ~ while for compositions I and II 3 or 4 steps of decomposition are observed and the temperature intervals widen and shift mainly to higher temperatures: 820 ~ in air, and 850 ~ in nitrogen atmosphere, A similar tendency was found for polyurethane elastomers (PUE) modified with P and P/Cl-containing antipyrenes [9], and also for RPUF containing additive antipyrenes with the same active elements, P and CI [1]. The latter decomposes in two stages in the interval from 230 to 670 ~ while for compositions I and II 3 or 4 steps of decomposition are observed and the temperature intervals widen and shift mainly to higher temperatures: 820 ~ in air, and 850 ~ in nitrogen atmosphere, A similar tendency was found for polyurethane elastomers (PUE) modified with P and P/Cl-containing antipyrenes [9], and also for RPUF containing additive antipyrenes with the same active elements, P and CI [1].…”

“…This requires the development of laboratory methods which are minimum time-, labour-and material-consuming and can provide .the maximum insight into the mechanism of the inhibitory effect of antipyrenes [1][2][3][4].Additive antipyrenes are not always efficient enough. It is shown that dynamic thermal analysis can register the changes resulting in the mechanisms and kinetics of the thermal decompositions of the investigated polyurethanes from comparatively low concentrations and differences in the concentrations and from differences in the chemical compositions and structures of the antipyrenes.…”

“…This requires the development of laboratory methods which are minimum time-, labour-and material-consuming and can provide .the maximum insight into the mechanism of the inhibitory effect of antipyrenes [1][2][3][4]. This requires the development of laboratory methods which are minimum time-, labour-and material-consuming and can provide .the maximum insight into the mechanism of the inhibitory effect of antipyrenes [1][2][3][4].…”

“…Because of the increased tendency to burning and the requirements for their combustion stability, the problem of selecting optimum antipyrene compositions [1] for polyurethanes is becoming an urgent necessity. This requires the development of laboratory methods which are minimum time-, labour-and material-consuming and can provide .the maximum insight into the mechanism of the inhibitory effect of antipyrenes [1][2][3][4].…”

Bio‐based engineered nanocomposite foam with enhanced mechanical and thermal barrier properties

“…However, there are some major deficiencies of rigid PU foam (PUF), which restricts their further compatibility and applications including inadequate mechanical strength, high flammability and thermal stability. In recent years, flame‐retardant rigid PU has attracted considerable attention owing to the increasing demand for rigid PU foam in the field of energy‐efficient building materials . The low flammability, may also particularly be useful for cabin interiors, where foams may be used in conjunction with other materials, such as leathers, that generally exhibit higher heat and smoke release values .…”