Effect of crosslinking agent on properties and morphology of water‐blown semirigid polyurethane foam

Abstract

ABSTRACTIn this article, triethanolamine (TEOA) is used as crosslinking agent, water‐blown semirigid polyurethane foams with different crosslinking agent content were prepared. The crosslinking density of polyurethane foams (PUFs) were adjusted and designed by changing the content of TEOA. The influence of crosslinking agent content on foaming process, apparent density, cell structure, microphase separation structure, thermal properties, and mechanical properties of PUFs has been studied. The cell structure, apparent density, and mean size of foams are closely related to foaming and gelation process. The results show that the crosslinking density is increased with the content of TEOA, and the swelling ratio of foams decreased from 294.9 to 194.7%. Dynamic mechanical analysis indicates that the promotion of crosslinking density can effectively restrict the movement of molecular chains, results in the glass‐transition temperature (T g) of foams increased from −14.2 to −8.6 °C. Thermogravimetric analysis states that the carbon residue of foams has increased by 5%, because the addition of crosslinking density contributes to reducing and limiting the formation of volatile degradation products. Fourier transform infrared spectroscopy is shown that the introduction of TEOA is not conducive to the microphase separation of urea, resulting in the decrease of foam mechanical properties. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46753.