In order to improve the flame retardancy of the rigid polyurethane foam, expandable graphite having different particle sizes and expansion rates was added to synthesize a rigid polyurethane foam. Urethane and isocyanurate ring was confirmed using fourier transform infrared spectroscopy (FTIR), and the heat resistance of the foam was analyzed using thermogravimetric analysis (TGA). The effect of expandable graphite on the mechanical properties of polyurethane foam was confirmed by measuring the compressive strength. The flame retardancy was analyzed through the UL94 V test, limited oxygen index (LOI), and measurement of the weight loss due to combustion. Although expandable graphite did not affect the compressive strength and heat resistance of polyurethane foam, in the flame retardant test, it was confirmed that the volume of char produced increased as the particle size and expansion rate of expandable graphite increased. Thus the flame retardant performance was improved.

경질 폴리우레탄 폼의 난연성을 개선하기 위해 입자크기와 팽창률이 다른 팽창흑연을 첨가하여 경질 폴리우레탄 폼을 합성하고 물성을 분석하였다. Fourier transform infrared spectroscopy(FTIR)를 사용하여 생성된 우레탄과 이소시아누레이트 링 결합을 확인하였으며, thermogravimetric analysis(TGA)를 이용해 폼의 내열성을 분석하였다. 팽창흑연이 폴리우레탄 폼의 기계적 물성에 미치는 영향은 압축강도 측정을 통해 확인하였다. 난연성은 UL94 V test와 한계산소지수(LOI) 및 연소에 따른 질량 손실률 측정을 통해 알아보았다. 팽창흑연이 폴리우레탄 폼의 압축강도와 내열성에 영향을 미치지는 않았으나 난연 시험에서 팽창흑연의 입자크기와 팽창률이 증가함에 따라 생성되는 char의 부피가 증가하여 난연성능이 개선되는 것을 확인할 수 있었다.

Keywords: polyurethane foam, expandable graphite, flame retardancy.