Open AccessSynthesis and Deblocking Investigations of Phenol Blocked Aliphatic Isocyanates and Their Application in the Development of Epoxy-Polyurethane Films
Author(s) -
Karthi Rajendran,
Vennila Srinivasan,
Sankar Govindarajan
Publication year - 2022
Publication title -
asian journal of chemistry/asian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.145
H-Index - 34
eISSN - 0975-427X
pISSN - 0970-7077
DOI - 10.14233/ajchem.2022.23574
Subject(s) - epoxy , phenol , polyurethane , chemistry , ultimate tensile strength , isophorone diisocyanate , fourier transform infrared spectroscopy , polymer chemistry , isocyanate , polyol , flexural strength , solubility , thermal stability , shore durometer , chemical engineering , organic chemistry , composite material , materials science , engineering
Phenol blocked hexamethylenediisocyanate adducts and polyisocyanates were synthesized and theirstructure was validated by FTIR, 1H & 13C NMR spectroscopy, TGA, DSC and CO2 evolution techniqueswere used to evaluate the deblocking temperature of blocked isocyanates. Gel time studies of blockedisocyanates with terathane polyol and solubility study of blocked isocyanates with different polyolswere conducted to demonstrate the structure-property correlation. Epoxy-polyurethane films wereproduced utilizing the blocked isocyanates reported in this work with epoxy resin and their structurewas verified by ATR Spectroscopy. TGA, DSC, shore A hardness, tensile strength and flexural strengthanalysis were used to investigate the thermal and mechanical characteristics of these films. The findingsof deblocking temperature and gel time revealed that unsubstituted phenol blocked isocyanates andpolyisocyanates deblock at lower temperatures and cure for a shorter time period than substitutedphenol blocked isocyanates. Thermal and mechanical characteristics of epoxy-polyurethane films basedon blocked polyisocyanates are satisfactory.