Ethyl rhamnolipids as a renewable source to produce biopolyurethanes

Abstract

Responding to increasing environmental concerns, lipids are attractive feedstock to produce bio-based polyurethanes. In this study, ethyl rhamnolipids were used to synthesize polyurethanes by reacting with 1,6-hexane diisocyanate (HDI). Rhamnolipids were produced by microbial fermentation, providing a novel source for biopolyurethanes. FTIR and gel content analyses confirmed that the hydroxyl groups on rhamnose residues were reacted with isocyanates. DSC analysis revealed an adjustable glass transition temperature (Tg) from 19 to 50°C. Ethyl rhamnolipids are liquid at 50°C, presumably because rhamnose is connected with fatty acid at a mid-chain position and the unique structure decreases the tendency to crystallize. The liquid polyols were found to have good mixing and reaction properties. The study may inspire future synthesis of novel lipid-based polyols.Practical applications: Use of vegetable oil-based polyols for polyurethane production had been extensively investigated. However, synthesis of these polyols mostly involved introduction of petroleumbased chemicals such as methanol and 1,2-propanediol. Rhamnolipids are natural glycolipids. Using ethyl rhamnolipids to prepare polyurethanes provides an alternative, more renewable route. In addition, it inspires synthesis of vegetable oil polyols by introducing natural sugars.

Rhamnolipid Adsorption in Soil: Factors, Unique Features, and Considerations for Use as Green Antizoosporic Agents

“…Rhamnolipids have been studied and/or proposed for various applications, such as bioremediation and antizoosporic biopesticide . Rhamnolipids can also be modified for surface-active properties and used to synthesize bio-based polymers …”

“…5 Rhamnolipids can also be modified for surfaceactive properties 6 and used to synthesize bio-based polymers. 7 Environmental concerns over extensive use of synthetic pesticides have motivated the searches for biopesticides. 8 Possible application of rhamnolipids in agriculture has been explored.…”

4D printing of polymeric materials for tissue and organ regeneration

“…In this regard, resin-based 3D printers (STL or DLP) are preferred for fabrication; liquid monomers or oligomers are placed in a resin bath and photopolymerization is performed layer by layer[15]. As a matter of fact, many thermoset polymers are obtained through a thermal curing process, but most of these types of thermosets are unprintable [56–64]. …”

Bio-Based Polymers for 3D Printing of Bioscaffolds

“…Environmental concerns have stimulated research efforts to explore the process of creating bio-based materials and their applications. 23–26 For instance, pyrolysis, hydrolytic cracking, and fermentation processes are common industrial methods used to extract sugars, starches, oils, etc. from crops.…”