Preparation of natural rubber-based polyol by oxidative degradation under supercritical carbon dioxide for flexible bio-based polyurethane foams

Abstract

Nowadays, polyurethane foams play a key role in widespread applications, and their market demand is still growing globally. This work aims to prepare hydroxyl telechelic liquid natural rubber, a bio-based polyol, as a sustainable raw material and to enhance elastic properties of soft segment bio-based polyurethane foams. A hydroxyl telechelic liquid natural rubber with a viscosity-average molecular weight of 4.2 × 103 g/mol was successfully produced by oxidative degradation of natural rubber with hydrogen peroxide in the presence of supercritical carbon dioxide, then modifying the chain-end functionality to obtain hydroxyl number of 59 mg KOH/g. The functionality of hydroxyl telechelic liquid natural rubber was confirmed by FT-IR and 1H-NMR. Bio-based polyurethane foams were then prepared by mixing the synthesized hydroxyl telechelic liquid natural rubber with commercial diisocyanate. Morphological properties and thermal stability of polyurethane foams were investigated.

Green rigid polyurethane foam from hydroxyl liquid natural rubbers as macro-hydroxyl polyols

“…Hydroxyl terminated natural rubbers (HTNRs), one type of the telechelic oligo-isoprenes, were successfully prepared by the selective and controlled degradation of natural rubber. [22][23][24] It can be used as a starting material to replace the petroleum products for flexible polyurethane foam synthesis.…”

Preparation and Characterization of Low-Molecular-Weight Natural Rubber Latex via Photodegradation Catalyzed by Nano TiO2

“…As NR is a renewable resource, its applications should not be limited to common products, but can be diversified through modifications to the NR chains to produce new rubbers with new properties. The molecular structure of NR consists of a double bond in its repeating units of cis -1,4-isoprene, which can be modified with regard to specific functional groups such as epoxidized natural rubber (ENR) [3], acrylated NR [4], carbonyl telechelic natural rubber (CTNR) [5], and hydroxyl telechelic liquid natural rubber (HTNR) [6,7].…”