Non‐isocyanate polyurethanes: synthesis, properties, and applications

Abstract

Conventional polyurethanes are typically obtained from polyisocyanates, polyols, and chain extenders. The main starting materials-isocyanates used in this process-raise severe health hazard concerns. Therefore, there is a growing demand for environment-friendly processes and products. This review article summarizes progress that has been made in recent years in the development of alternative methods of polyurethane synthesis. In most of them, carbon dioxide is applied as a sustainable feedstock for polyurethane production directly or indirectly. The resulting nonisocyanate polyurethanes are characterized by a solvent-free synthesis, resistance to chemical degradation, 20% more wear resistance than conventional polyurethane, and can be applied on wet substrates and cured under cold conditions. Three general polymer synthetic methods, step-growth polyaddition, polycondensation, and ring-opening polymerization, are presented in the review. Much attention is given to the most popular and having potential industrial importance method of obtaining non-isocyanate polyurethanes, poly(hydroxy-urethane)s, based upon multicyclic carbonates and aliphatic amines. It is evident from the present review that considerable effort has been made during the last years to develop environmentally friendly methods of obtaining polyurethanes, especially those with the use of carbon dioxide or simple esters of carbonic acid. Scheme 1. [n,m]-Polyurethane synthesis from alkylene bis(chloroformate)s and diamines. Scheme 2. Synthesis of NIPU in the reaction of alkylene bis(phenyl carbonate) with diamine. Scheme 3. Synthesis of [n]-polyurethane from aminoalkyl chloroformate.Scheme 4. Synthesis of [6]-polyurethane from 6-amino-1-hexanol. Scheme 5. Synthesis of allylcarbamate monomer and poly(thioether-urethane).708 Scheme 8. Synthesis of NIPU via AB-type self-polycondensation.Scheme 7. Multistep synthesis of isosorbide-based polyurethane (polycondensation mode). Scheme 6. Multistep synthesis of isosorbide-based polyurethane (polyaddition mode).

Effects of cellulose fiber content on physical properties of polyurethane based composites

“…Since its first laboratory synthesis in 1937, polyurethane (PU) has rapidly grown to be one of the most diverse and widely-used materials which constantly stimulate the interest of researchers because of its several interesting properties such as low density, thermal conductivity, moisture permeability, a high strength to weight ratio and dimensional stability [31][32][33][34][35][36][37][38]. Moreover, the formulation and reaction conditions can be readily adjusted to synthesize different PU materials with desired properties for specific applications.…”

Synthesis, structure and properties of poly(ester-urethane)s obtained using bio-based and petrochemical 1,3-propanediol and 1,4-butanediol

“…The increasing interest in the area of bio-based substances (e.g., polyols [1,2,15,16], chain extenders [17][18][19][20] and diisocyanates [21,22]) used as a components in the synthesis of polyurethanes is observed. According to the literature, the non-isocyanates polyurethanes synthesized using natural resources (e.g., vegetable oils, bio-based diamines, fatty acids and glycerol) are also known [23,24].…”

A novel 2,5-furandicarboxylic acid-based bis(cyclic carbonate) for the synthesis of biobased non-isocyanate polyurethanes

“…6,9,10 Environmental and health hazard concerns over the use of isocyanates have led to an increasing demand for the development of environmentally-friendly processes for PU production without using toxic isocyanates. 8 The development of novel non-isocyanate polyurethanes (NIPUs) has received increased attention in recent years. Generally, linear NIPUs can be synthesized from three synthetic routes: the copolymerization of an aziridine with CO 2 , the transurethanization between a bis(carbamate) and a diol, and the ring-opening polyaddition between a bis(cyclic carbonate) and a diamine.…”

“…6 The third route is currently the most studied one because of its large potential for industrial production, and numerous bis(cyclic carbonate)s are being tested in laboratories for the use as precursors for NIPU production. 8 Because bis(cyclic carbonate)s are generally synthesized from the reaction of diepoxides with CO 2 , the production of NIPU via this route is considered to be an important strategy for chemical xation of CO 2 .…”

“…[3][4][5][6] However, isocyanates are considered to be hazardous to the environment and human health. 4,7,8 Moreover, isocyanates are typically produced from the reactions of amines with phosgene, which can be extremely dangerous to humans. 6,9,10 Environmental and health hazard concerns over the use of isocyanates have led to an increasing demand for the development of environmentally-friendly processes for PU production without using toxic isocyanates.…”