Doctoral Dissertations
Date of Award
6-1982
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Major
Chemistry
Major Professor
James F. Kinstle
Committee Members
Richard Pagni, Clifton Woods
Abstract
The surfaces of poly(vinyl chloride) and high density polyethylene films were modified using isocyanate chemistry. Surface modifications were accomplished using substitution and elimination/addition reactions. Qualitative and semi quantitative characterizations were accomplished using infrared internal reflection spectroscopy.
Poly(vinyl chloride) was modified via a substitution of the chlorines using potassium cyanate solubilized into cyclohexane with 18- crown-6 ether. A carbonyl band appeared in the internal reflection spectrum intead of the isocyanate band. A nylon-1 type structure is proposed. Substitution reactions on poly(vinyl chloride)'s surface were also accomplished with potassium cyanate in the presence of a large excess of ethylene glycol. The intermediate isocyanate group was trapped to form the 2-hydroxyethyl N-poly(vinyl chloride) carbamate modified polymer. During this modification, dehydrochlorination was a competing reaction that resulted in a conjugated double bond system. Evidence for the double bonds was infrared internal reflection spectroscopy and colored films. The double bonds added chlorine quantitatively to produce colorless films. Solvolysis between allylic chlorines and ethylene glycol also occurred on the film's surface.
To accomplish substitution reactions on high density polyethylene, useable functionality was first introduced by chlorination. Comparison of infrared transmission and internal reflection spectroscopy showed the chlorination occurred predominately on the polymer's surface. Attempted substitution reactions using potassium cyanate were unsuccessful producing brown films, an indication of conjugated double bonds.
To incorporate isocyanate groups on poly(vinyl chloride) and chlorinated high density polyethylene, elimination/addition reactions were used. Both polymers were efficiently dehydrochlorinated with sodium methoxide. Isocyanate groups were then introduced onto their surfaces using two methods. The first method was an addition reaction using isocyanic acid and t-butyl hypochlorite. The second method used the pseudo halogen, chloroisocyanate. Introduction of the isocyanate group onto eliminated poly(vinyl chloride) and chlorinated high density polyethylene occurred in a higher yield using isocyanic acid and t-butyl hypochlorite than with chloroisocyanate. For eliminated poly(vinyl chloride) both methods produced colorless films; however, for eliminated chlorinated high density polyethylene, a slight yellow color remained.
Recommended Citation
Taylor, James Wayne, "The surface modifications of poly(vinyl chloride) and high density polyethylene using isocyanate chemistry. " PhD diss., University of Tennessee, 1982.
https://trace.tennessee.edu/utk_graddiss/13332