Indian Journal of Advances in Chemical Science, Volume: 10, Issue : 1, January 2022

ISSN No.: 2320-0898 (Print); 2320-0928 (Electronic)

DOI: 10.22607/IJACS.2022.1001007

Article

Effect of Catalysts on Deblocking and Cure Reactions of Phenol-blocked
Aliphatic Diisocyanate Adducts and Pre-polymers

Karthi Rajendran, Vennila Srinivasan, Sankar Govindarajan*

ABSTRACT

Effect of catalysis on deblocking and cure reactions of phenol-blocked aliphatic diisocyanate adducts and pre-polymers were investigated using CO2 evolution method and cure time studies, respectively. Completion of cure reaction of blocked aliphatic diisocyanates and Terathane 2000 was confirmed by ATR spectroscopy. Tertiary amines and organotin compounds were used as catalysts for the deblocking and cure reactions, and the organotin catalyst demonstrated better catalytic activity. However, due to the synergistic effect, a combination of tertiary amine and organotin catalysts demonstrated superior catalytic activity than individual ones. The influence of catalyst concentration on the cure reaction was also investigated. The lowest deblocking temperature of 35°C was achieved in the case of unsubstituted phenol-blocked aliphatic diisocyanate pre-polymer in solution state using a mixture of DBTDL and DABCO, and the cure time was found to be 25 min as it is an important factor for thermal cure process need to be carried out at mild conditions.

Key words: Amine catalysis, Cure reaction, Deblocking, Organotin catalysis, Phenol-blocked aliphatic diisocyanate, Synergistic effect, Terathane 2000.

[Download Full Article PDF]