Thermal Degradation of Carbamates of Methylenebis-(4-phenyl Isocyanate)¹

Synthesis, structure and properties of poly(ether-urethane)s synthesized using a tri-functional oxypropylated glycerol as a polyol

“…Thermal degradation mechanism of polyurethanes is a very complex process, especially in the case of polyurethanes obtained with using multifunctional components. The thermal decomposition of urethane bonds was investigated by Dyer et al [35][36][37], who studied the thermal degradation of the model urethanes (i.e., carbamates) and indicated three ways of the urethane linkage cleavage at low temperatures (200-300°C), i.e., (1) dissociation to isocyanate and alcohol, (2) dissociation to primary amine, olefin and carbon dioxide, and (3) elimination of carbon dioxide, leading to formation of a secondary amine. The thermal decomposition of polyurethanes is well described in the scientific literature [38][39][40].…”

Selected topics in biomedical polyurethanes. A review

“…One block of the polymer chain consists of a relatively long, flexible "soft segment" derived from a hydroxylterminated aliphatic polyester, polyether or poly-alkene, with a molecular weight between 500 and 5 000. The second, highly polar and rather stiff block of the copolymer, commonly refered to as the "hard segment" is formed by the reaction of diisocyanates with low molecular weight diol or diamine chain extenders [2][3][4][5][6][7][8][9][10][13][14][15].…”

“…Traces of metals and salts in the chemicals used, accelerate all these side reactions. Thus the use of high purity reagents is absolutely essential for synthesis of high molecular weight linear copolyurethanes [1][2][3][4][5][6][7][8][9][10][13][14][15].…”

Thermal stability of molecularly uniform oligourethanes based on 1,5-naphthalene diisocyanate and 1,4-butanediol

“…However, polyurethanes which are synthesized by polyaddition of diisocyanates and diols show a limited stability due to retro-urethanization reactions of the urethane linkage at higher temperatures [1][2][3][4] . In order to optimize the processing without decomposition and also to improve the service temperature range towards higher temperatures, the knowledge of the thermal stability of PUR is of utmost importance.…”