Access to nonisocyanate poly(thio)urethanes: A comparative study

High-Performance Nonisocyanate Thermoplastic Polythiourethane with High Hydrogen Bond Content

Nonisocyanate polyurethane (NIPU) has been extensively studied because of its sustainability potential. However, the low reactivity of five-membered cyclocarbonates with amines and the side reactions at higher temperatures always sacrifice the performance of NIPUs. In this work, a bisphenol-S cyclic thiocarbonate and different amino-terminated dimer-acid polyamides (DAPAs) were used to prepare nonisocyanate polythiourethanes (SPTU-DAs). Wherein bisphenol-S acts as a hard segment due to a π-π package, plentiful hydrogen bonds introduced by DAPA units induce crystallization and nanophase separation. They both endow the NIPUs with high mechanical performance. Meanwhile, active cyclic thiocarbonate, instead of cyclic carbonate, ensures rapid synthesis under mild conditions without side reactions. The experimental results of DSC, WAXD, and DMA confirmed the existence of crystallization of SPTU-DAs. The as-prepared thermoplastic polythiourethane has a maximum strength of more than 10 MPa, which is stronger than those of the cross-linked nonisocyanate polythiourethanes reported. It is of key significance to obtain the high performance of nonisocyanate polythiourethanes.

Cascade (Dithio)Carbonate Ring Opening Reactions for Self-Blowing Polyhydroxythiourethane Foams

Polyurethane (PU) foams are very common materials that have found many applications over the years. Their use is constantly improving due to their unique physical properties and easy blowing which does not require the addition of a blowing agent. Greener routes have been explored in the recent years to replace isocyanates. One of the most promising routes is leading to Polyhydroxyurethanes (PHU). However, with PHUs, external blowing agent are usually required to obtain a foam. Thus, our work focuses on PHU foam synthesis using in situ reaction to produce NIPU foam. Hence, the aminolysis of thiocyclic carbonate triggers Pearson reaction between released thiols and cyclic carbonates which serves as a chemical blowing agent. This article is protected by copyright. All rights reserved.

Cationic ring-opening polymerization of a five membered cyclic dithiocarbonate having a tertiary amine moiety

A dibenzylamine derived cyclic dithiocarbonate (1) undergoes ring-opening polymerization due to the greater reactivity of exocyclic sulfur compared to the tertiary amine with methyl triflate.

Advances in the use of CO2 as a renewable feedstock for the synthesis of polymers

Carbon dioxide offers an accessible, cheap and renewable carbon feedstock for synthesis. Current interest in the area of carbon dioxide valorisation aims at new, emerging technologies that are able to provide new opportunities to turn a waste into value. Polymers are among the most widely produced chemicals in the world greatly affecting the quality of life. However, there are growing concerns about the lack of reuse of the majority of the consumer plastics and their after-life disposal resulting in an increasing demand for sustainable alternatives. New monomers and polymers that can address these issues are therefore warranted, and merging polymer synthesis with the recycling of carbon dioxide offers a tangible route to transition towards a circular economy. Here, an overview of the most relevant and recent approaches to CO2-based monomers and polymers are highlighted with particular emphasis on the transformation routes used and their involved manifolds.

Isocyanate-Free Polyurethane Coatings and Adhesives from Mono- and Di-Saccharides

Mostly biosourced non-isocyanate polyurethanes (NIPU) were prepared from mono- and disaccharides, namely glucose and sucrose, reacted with dimethyl carbonate and hexamethylene diamine. The main aim of this research was to show that NIPU can be prepared from mono- and disaccharides, this just being an initial exploratory work and its sole main aim. The oligomers obtained were detected by MALDI-ToF, CP-MAS ¹³C NMR, and FTIR spectrometries. The glucose-derived NIPU were shown to harden at a markedly lower temperature than the sucrose-derived ones and to be easier to handle and spread. The NIPU obtained were applied as wood and steel surface coatings and tested by the sessile drop test (on wood) and cross-cut test (on steel) with encouraging results. The glucose NIPU gave good surface coating results already at 103 °C, while the sucrose NIPU yielded good results only at a markedly higher temperature of hardening. The NIPU saccharide resins were also tested as thermosetting wood joint adhesives with the glucose NIPU yielding very encouraging results.

A thioglycerol route to bio-based bis-cyclic carbonates: poly(hydroxyurethane) preparation and post-functionalization

The present work is dedicated to the design of novel sulfur-substituted cyclic carbonates from thioglycerol, fatty acids and sugar derivatives.

A study of cyclic carbonate aminolysis at room temperature: effect of cyclic carbonate structures and solvents on polyhydroxyurethane synthesis

In recent years, intensive research and development have been carried out for the synthesis of isocyanate free polyurethanes from the reaction between five-membered cyclic carbonates and amines to yield polyhydroxyurethanes (PHU).

Wood adhesive application of poly(hydroxyurethane)s synthesized with a dimethyl succinate-based amide backbone

Novel NIPUs with dimethyl succinate-based amide backbone – synthesis, properties and application in wood joints

Atom economical synthesis of di- and trithiocarbonates by the lithium tert-butoxide catalyzed addition of carbon disulfide to epoxides and thiiranes

The lithium tert-butoxide catalyzed addition of CS₂ to epoxides and thiiranes under mild conditions is reported. A mechanism has been proposed taking into account the regio- and stereochemical outcome of the reaction.

Activated lipidic cyclic carbonates for non-isocyanate polyurethane synthesis

Activated 5-membered cyclic carbonates were prepared from glycerol and fatty acid derivatives.

Fatty acid-based (bis) 6-membered cyclic carbonates as efficient isocyanate free poly(hydroxyurethane) precursors

Highly reactive (bis) 6-membered cyclic carbonates (b6CC) were prepared from fatty acid derivatives. Isocyanate free poly(hydroxyurethane)s were then synthesized and characterized.