Glass transition and thermal degradation of rigid polyurethane foams derived from castor oil–molasses polyols

• Published in: Journal of thermal analysis and calorimetry 2013-02, Vol.111 (2), p.1545-1552
• Main Authors: Hatakeyama, H., Matsumura, H., Hatakeyama, T.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Applied sciences; Calorimetry; Castor oil; Chemical reactions and properties; Chemistry; Chemistry and Materials Science; Degradation; Dextrose; Electric properties; Exact sciences and technology; Fructose; Glucose; Glucose metabolism; Inorganic Chemistry; Isocyanates; Measurement Science and Instrumentation; Organic polymers; Physical Chemistry; Physicochemistry of polymers; Polymer Sciences; Polyols; Thermal properties; Toy industry
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-012-2501-5

Rigid polyurethane (PU) foams having saccharide and castor oil structures in the molecular chain were prepared by reaction between reactive alcoholic hydroxyl group and isocyanate. The apparent density of PU foams was in a range from 0.05 to 0.15 g cm −3 . Thermal properties of the above polyurethane foams were studied by differential scanning calorimetry, thermogravimetry and thermal conductivity measurement. Glass transitions were observed in two steps. The low-temperature side glass transition was observed at around 220 K, regardless of castor oil content. This transition is attributed to the molecular motion of alkyl chain groups of castor oil. The high-temperature side glass transition observed in the temperature range from 350 to 390 K depends on the amount of molasses polyol content. The high-temperature side glass transition is attributed to the molecular motion of saccharides, such as sucrose, glucose, fructose as well as isocyanate phenyl rings, which act as rigid components. Thermal decomposition was observed in two steps at 570 and 620–670 K. Thermal conductivity was observed at around 0.032 J sec −1  m −1  K −1 . Compression strength and modulus of PU foams were obtained by mechanical test. It was confirmed that the thermal and mechanical properties of PU foams could be controlled by changing the mixing ratio of castor oil and molasses for suitable practical applications.