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

Abstract

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.

Biorenewable thermosetting copolymer based on soybean oil and eugenol

“…It was found that the storage modulus at room temperature, the glass transition temperature, and the crosslink density of the epoxy blend decreased with increasing content of EVO, while fracture toughness and flexural modulus were increased with increasing amount of EVO [17][18][19]. The epoxide rings of EVO can be ring-opened by alcohols [20] or acids [21,22] to introduce other functionalities. After the epoxide rings had been opened, hydroxyl groups were introduced, and polyurethanes with a wide range of properties can be produced by the reactions between hydroxyl groups and diisocyanates [23].…”

Novel bio-based epoxy-polyurethane materials from modified vegetable oils – synthesis and characterization

“…On the other hand polymer material based on HDI is characterized by high elasticity, two times higher tensile strength and modulus of elasticity than polyurethane elastomer based on polyol from soybean oil and HDI, described in the literature [29]. At the same time it presents comparable hardness in the Shore's A scale (67.4-87.7 Sh°A) [30][31][32] to polyurethane elastomers based on different vegetable oils. Moreover, the analysis of mechanical tests indicate that, application of aromatic isocyanate, toluene-2,4-diisocyanate, results in obtaining the composition Table 4.…”

Carbon nanofibers reinforced soy polyol-based polyurethane nanocomposites

“…The hydroxyl (-OH) numbers of polyols were 168, 224, 248 mg KOH g -1 , respectively. The neat soy polyol-based polyurethane (PU) was prepared from three polyols with IPDI using previously reported methods [32], which preparation procedures are shown in Fig. 1.…”