Acoustic Performance and Flame Retardancy of Ammonium Polyphosphate/Diethyl Ethylphosphonate Rigid Polyurethane Foams.

Huiping Zhang,Ying Yan,Xiongxian Lyu,Zijun Huang

doi:10.3390/polym14030420

Abstract

Flame-retardant water-blown rigid polyurethane foams (RPUFs) modified by ammonium polyphosphate (APP) and diethyl ethylphosphonate (DEEP) were synthesized by a one-pot free-rising method. We performed scanning electron microscopy (SEM), compression strength tests, acoustic absorption measurements and thermogravimetric analysis, as well as limited oxygen index, vertical burning and cone calorimeter tests to investigate the mechanical properties, acoustic performance and flame retardancy of the foams. SEM confirmed that the open-cell structures of the foams were successfully constructed with the introduction of a cell-opening agent. Upon using 20 php APP, the average acoustic absorption coefficient of the foam reached 0.535 in an acoustic frequency range of 1500–5000 Hz. The results of thermogravimetric analysis demonstrated that the incorporation of APP and DEEP can effectively restrain mass loss of RPUFs during pyrolysis. In particular, the compressive strength of a foam composite containing 5 php APP and 15 php DEEP increased to 188.77 kPa and the LOI value reached 24.9%. In a vertical burning test and a cone calorimeter test, the joint use of APP and DEEP endowed RPUFs with a V-0 rating and they attained a THR value of 23.43 MJ/m2. Moreover, the addition of APP improved the acoustic absorption performance of the foam, verified by acoustic absorption measurements. Considering potential applications, the formulation containing 15 php APP and 5 php DEEP could be used in the preparation of a new flame-retardant acoustic absorption rigid polyurethane foam.

Highlights

Since polyurethane foam was first synthesized in the 1940s, appreciable attention has been paid to them for their wide range of uses in different areas
Considering potential applications, the formulation containing 15 php ammonium polyphosphate (APP) and 5 php diethyl ethylphosphonate (DEEP) could be used in the preparation of a new flame-retardant acoustic absorption rigid polyurethane foam
rigid polyurethane foams (RPUFs) has emerged as an interesting candidate, owing to its porous structure meeting the demand of acoustic absorption

Summary

Introduction

Since polyurethane foam was first synthesized in the 1940s, appreciable attention has been paid to them for their wide range of uses in different areas. Common usages such as in tubes, hose products, wall coverings and seals are derived from their ease of processing [1]. Its highly developed pore structure gives it potential to be applied in numerous fields. Perplexing and harmful noise arouses interest in developing noise mitigation strategies, and one strategy is to exploit novel and effective acoustic absorption materials. RPUF has emerged as an interesting candidate, owing to its porous structure meeting the demand of acoustic absorption

Methods

Results

Conclusion