화학공학소재연구정보센터
Polymer, Vol.49, No.16, 3399-3412, 2008
Crosslinking systems and film properties for surfactant-free latexes based on anhydride-containing polymers
In this paper, we report novel crosslinking systems for surfactant-free artificial latexes based on anhydride-containing polymers. Surfactant-free latexes with average particle diameters of about 150 nm and a zeta-potential of -70 mV have been successfully obtained from anhydride-containing polymers with various T(g)s and polarities, including poly(octadecene-alt-maleic anhydride) (POMA) and maleinized polybutadiene (PBDMA). When adipic dihydrazide (ADH), a water-soluble crosslinker, was added to these latexes, no differences in particle size or zeta-potential were found; the presence of ADH did not affect the latex stability. In contrast, when 1,6-diaminohexane (DAH) was added to these latexes, it was found to interact with the polymer particles, indicated by a decrease in absolute zeta-potential for the latex particles and even gelation in the case of POMA. From H-1 NMR and LC-MS studies, it has been shown that no free DAH was present after being added to the latex, while free, unreacted ADH was present in aqueous phase upon its addition to the latex. Kinetic studies revealed that irreversible imide formation between anhydride and ADH took place at temperatures of 90 degrees C and above. In comparison, DAH only formed imides with the copolymers at significantly higher curing temperatures, i.e. > 130 degrees C. Furthermore, the film formation of these latexes was studied; for the different copolymer latexes, curing at temperatures above the T-g of the respective copolymers led to homogeneous film formation. These systems based on surfactant-free latexes crosslinked with ADH have displayed promising properties for future coating applications. (C) 2008 Elsevier Ltd. All rights reserved.