Synthesis and Characterization of Statistical and Block Copolymers of n-Hexyl Isocyanate and 3-(Triethoxysilyl) Propyl Isocyanate via Coordination Polymerization.

Abstract

Well-defined statistical copolymers of n-hexyl isocyanate, HIC, and 3-(triethoxysilyl)propyl isocyanate, TESPI, were synthesized via coordination polymerization mechanism, employing a chiral half-titanocene complex as initiator. The monomer reactivity ratios of the statistical copolymers were calculated using linear graphical methods and the computer program COPOINT in the frame of the terminal model. The molecular and structural characteristics of the copolymers were also calculated. The kinetics of the thermal decomposition of the statistical copolymers was studied by Thermogravimetric Analysis, TGA, and Differential Thermogravimetry, DTG, and the activation energy of this process was calculated employing several theoretical models. In addition, block copolymers constituted from PHIC and PTESPI blocks were synthesized by sequential coordination polymerization. All samples were characterized by nuclear magnetic resonance, NMR, spectroscopy and size exclusion chromatography, SEC. The thermal stability of the blocks was also studied by TGA and DTG and compared to the corresponding statistical copolymers.