The foaming dynamic characteristics of polyurethane foam

Polyurethane foam is a kind of polymer composite material. The foaming turgidity and reaction temperature of polyurethane foam are closely related to its mechanical properties. According to our present knowledge, this study is the first time that fiber optic sensing technology has been applied to monitor the dynamics change in the foaming turgidity and reaction temperature of polyurethane foam during its preparation. The effects on the foaming expansion force, contractile force, and reaction temperature are studied through changing proportion of water among the ingredients of the polyurethane foam. The results have shown that the fiber optic Bragg grating wavelength varies due to the reaction temperature and foaming power. In the reaction process, the foaming expansion force can make the maximum wavelength change of fiber optic Bragg grating 1–3.5 nm, equivalent to 1000–3541 micro strain. And the highest temperature of the reaction was 42.6°C. The wavelength shifts of the fiber optic Bragg gratings were closely related to the reaction temperature and foaming power. The results show that fiber optic sensing technology can be used for the online kinetics monitoring of the reaction process of polyurethane foam plastics. The data obtained from the fiber optic Bragg grating could be used for the design and performance prediction of new polyurethane foam materials.