A STUDY ON INTERCALATION AND EXFOLIATION OF LAYERED SILICATE NANOP ARTICLES IN THERMOPLASTIC POLYURETHANES

摘要

Thermoplastic polyurethanes serve as an attractive system for the study of intercalation and exfoliation of layered silicate nanoparticles. The clay galleries are easily intercalated by low molecular weight diisocyanates, polyols, and butanediol before carrying out condensation polymerization. A majority of existing studies reported intercalation and subsequent polymerization in solutions and obtained fully exfoliated clay structures, although industrial implementation of such technology requires development of bulk polymerization schemes. In this study, we utilized the unreacted isocyanate groups in the chains of prepolymer and chain extended polymers to tether nanoclay particles and studied the properties of the resultant materials produced by sequential addition of organically treated silicate particles into prepolymer and to the fully formed polymer chains. As high as 216% increase in tensile strength and 87% increase in elongation at break were observed with 1-2 wt% organically treated clay particles.