Thermoplastic Polyurethanes Stemming from Castor Oil: Green Synthesis and Their Application in Wood Bonding

Abstract

Abstract:We report an efficient and green approach to synthesize a linear castor oil-based polyurethane (CPU) without using any solvent or catalyst. Diol monomers were first synthesized by the aminolysis reaction between castor oil and diamines; this was accomplished within 6 h at 130 • C. Polymerization of the diols and isocyanate was further confirmed by Fourier transform infrared (FTIR), 1 H-nuclear magnetic resonance ( 1 H-NMR), and gel permeation chromatography analyses. The resultant CPUs showed a good thermal stability with an initial degradation temperature higher than 300 • C, and their mechanical and wood bonding property can be modulated by the structures of diamine. In addition, the CPUs possessed a satisfying water resistance property with the water absorption amount lower than 2%. The green conversion of castor oil to thermoplastic polyurethane affords new opportunities in bio-based industries.

Polymers and Composites Derived from Castor Oil as Sustainable Materials and Degradable Biomaterials: Current Status and Emerging Trends

“…A green method to synthesize CO-based thermoplastic PUs has been reported by Li et al 85 (Scheme 4). A thermal degradation study revealed that the resultant PU is thermally stable as the primary degradation temperature is higher than 300 °C.…”

“… a Reprinted with permission from ref . Copyright 2017 Multidisciplinary Digital Publishing Institute.…”

Synthesis, Characterization, and Soil Burial Degradation of Biobased Polyurethanes

“…For example, the epoxidation processes of castor oil (followed by reaction with polyols for ring opening) is poorly eco-friendly, since it requires the use of hydrogen peroxide, organic acids, and large amount of energy [13,14]. Moreover, other procedures, such as the aminolysis reaction between castor oil and diamines, are tedious and require several purification steps [15]. In addition, no attention has been paid to the objective analysis of the sustainability characteristics of the newly developed castor oil-derived PUs, such as considerations about the environmental impact of the synthesis, the petroleum nature of the employed isocyanates and other reagents, the amount of waste produced, e.g., by calculating the environmental factor (E-factor) of the synthesis, or the end-life treatments [16,17].…”

Biodegradation Study of Polyurethanes from Linseed and Passion Fruit Oils

“…Polyurethanes (PUs) are very important for the chemical industry because they are light, resistant, practical, versatile, durable, and relatively inexpensive materials [1][2][3][4]. Because of their durability, PUs are typically resistant to biodegradation in landfills, with no signs of deterioration after decades in the soil, occupying large areas, contributing to plastic accumulation and polluting the environment [2,5,6].…”