Title

An investigation of the effects of polymer structure upon the dissociation temperature of macromolecular-blocked isocyanates

Date of Award

1986

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Polymers and High Performance Materials

First Advisor

Shelby Thames

Advisor Department

Polymers and High Performance Materials

Abstract

The effect of polymer structure upon the dissociation temperatures, rates, and mechanism of polymeric blocked isocyanates is discussed. Specifically, a blocked isocyanate monomer, based on the reaction of isocyanatoethyl methacrylate and pentachlorophenol, was incorporated into acrylic co- and terpolymers were synthesized and characterized. The resulting co- and terpolymers possessed a dissociation temperature range in excess of 150$\sp\circ$C and shelf lives between 2 and 13 months. Dissociation temperatures of the monomer and polymers were determined through the use of differential scanning calorimetry and hydrogen bonding ability of the materials was elucidated via fourier transform spectroscopy. A relationship among the dissociation temperature, T$\rm \sb{g}$, shelf life, and hydrogen bonding ability of each of the polymers was established. Acrylic co- and terpolymers possessing relatively low T$\rm \sb{g}$s exhibited low dissociation temperatures (ambient temperature to 60$\sp\circ$C), significant hydrogen bonding, and abbreviated shelf lives (2-4 months). On the other hand, acrylic co- and terpolymers possessing relatively high T$\rm \sb{g}$s exhibit elevated curing temperatures (165-185$\sp\circ$C), decreased hydrogen bonding, and shelf lives of 13 months.