Castor oil‐based polyols with gradually increasing functionalities for biopolyurethane synthesis

Abstract

In this research, castor oil‐based polyols with gradual increasing functionalities were prepared using thiol‐ene photo click reaction. The polyols were prepared by facile and efficient photo‐click reaction using thiols with different number of hydroxyl groups. The polyols were successfully synthesized using a modified bio‐oxygen demand (BOD) reactor and their structures were characterized. The hydroxyl number of the prepared polyols gradually increased depending on the thiol used for preparation. The increased hydroxyl number resulted in increased crosslinking densities for the prepared polyurethanes. The effect of the increasing crosslinking density and structure of the polyols on the mechanical and thermal properties of polyurethane were investigated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48304.

Bio-Based Polyurethane Foams with Castor Oil Based Multifunctional Polyols for Improved Compressive Properties

“…The hydroxyl values of CO, COM, and COT were analyzed according to the ASTM D1957-86 standard and the measured values were 152, 259, and 366 mg KOH/g, respectively, which correspond to the values in our previous report [26]. These results confirmed that the synthesis of adequate modified polyols was required for the preparation of PU foams was successful.…”

“…It contains a hydroxyl group at the C-12 position in nature, which allows it to be utilized in PU production [ 25 ]. However, the successful commercialization of PU produced from CO is limited by the poor mechanical properties of the foam and low productivity, which are attributed to the inherent characteristics of CO, such as low hydroxyl value, low reactivity of secondary OH groups, and steric hindrance [ 26 ]. Recently, several studies have focused on overcoming these drawbacks through the modification of castor oil by epoxidation [ 27 ], transesterification [ 28 ], ozonolysis [ 29 ], and radical addition [ 18 ].…”

“…The thiol-ene click reaction has been attracting considerable attention as a facile and efficient method for producing multifunctional materials [ 30 ]. Based on its simple reaction conditions, high rate and yield, and stereo-selectivity, as well as ease of purification, this approach has been considered as a new route to develop vegetable oils as a feedstock for PU synthesis [ 20 , 26 ]. Alagi et al developed thiol-grafted vegetable oil-based polyols and utilized them to prepare thermoplastic PUs [ 31 ].…”

Fabrication of silane-grafted graphene oxide and its effect on the structural, thermal, mechanical, and hysteretic behavior of polyurethane

“…In our previous study, we reported the thermal decomposition behavior of PU prepared using CO-based multifunctional polyols and various diisocyanates. It has been confirmed that there is no significant effect on the second stage thermal decomposition behavior for vegetable oil-based PUs regardless of the type of polyol and diisocyanate used 12 . The final step is due to the complete degradation of the remainders of the second stage.…”

One‐Pot Two‐Step Synthesis of Hydroxymethylated Unsaturated VHOSO and Its Application to the Synthesis of Biobased Polyurethanes

“…[10] To increase the renewable content, bio-PUs are mainly obtained by reacting diisocyanates and polyols resulting from functionalization of vegetable oils extracted from various plants (rapeseed, soybean, palm, etc.). [11][12][13][14][15][16] Natural vegetable oils contain saturated and unsaturated triglycerides but do not contain hydroxyl groups, with the exception of castor and lesquerella oils. However, functionalization of the carbon-carbon double bond through epoxidation followed by oxirane ring-opening, [17][18][19] hydroformylation followed by hydrogenation, [20] ozonolysis, [20] or thiol-ene coupling [21] affords a wide range of biobased polyols, enabling reactions with diisocyanates to get bio-PUs.…”