Polyurethane networks from different soy-based polyols by the ring opening of epoxidized soybean oil with methanol, glycol, and 1,2-propanediol

• Published in: Journal of applied polymer science Vol. 114; no. 1; pp. 125 - 131
• Main Authors: Wang, Cheng-Shuang, Yang, Li-Ting, Ni, Bao-Lian, Shi, Guang
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 05-10-2009; Wiley
• Subjects: Applied sciences; biomaterials; Exact sciences and technology; Glassy; Glycols; Methyl alcohol; Networks; Organic polymers; Physicochemistry of polymers; Polycondensation; Polyols; Polyurethane resins; polyurethanes; Preparation, kinetics, thermodynamics, mechanism and catalysts; renewable resources; resins; Ring opening; Soybeans; renewable resources; resins; Molecular structure; Crosslink density; Mechanical properties; Vegetable oil; networks; Polyaddition; polyurethanes; Tensile strength; Thermal stability; Thermal properties; Preparation; Polyurethane; Crosslinked polymer; Property structure relationship; Polyol; biomaterials; Soybean oil
• ISSN: 0021-8995; 1097-4628; 1097-4628
• DOI: 10.1002/app.30493

A series of polyols with a range of hydroxyl (OH) numbers based on soybean oil and epoxidized soybean oil were prepared by oxirane ring opening with methanol, glycol, and 1,2-propanediol. The polyols, with average functionalities varying from 2.6 to 4.9, were characterized. Novel cast polyurethane resins were synthesized from these polyols and 2,4-toluene diisocyanate. The sol fraction of the network decreased as the OH number of the polyol from which it was synthesized increased. None of the samples were completely soluble. The crosslinking density of the polyurethanes correlated directly with the functionality of the polyols. The thermal and mechanical properties of the cast resins were characterized with differential scanning calorimetry and thermogravimetry. The glass-transition temperature increased with the OH number increasing, and the thermal stability of the resins was slightly decreased with the OH number increasing. The tensile strength at break increased with the OH number increasing. Polyurethanes prepared from polyols with OH numbers higher than 170 mg of KOH/g were glassy, whereas those with OH numbers below that value were rubbery. Glassy polyurethanes displayed decent mechanical strength, whereas rubbery samples showed relatively poor elastic properties and were characterized by lower strength.