화학공학소재연구정보센터
Journal of Materials Science, Vol.49, No.7, 2853-2863, 2014
Establishment of a novel surface-imprinting system for melamine recognition and mechanism of template-matrix interactions
A surface molecular-imprinting system was developed on polypropylene (PP) fiber for melamine (Mel) as an N-containing template. In this article, acrylic acid was introduced onto the surface of PP for template binding. Subsequently, binding sites on PP were stabilized by crosslinking with ethylene glycol diglycidyl ether in the presence of Mel. The imprinted fiber (MIF-Mel) prepared with the optimal 15 % crosslinking density showed best-imprinting effect, with an imprinting factor of 2.18 respect to nonimprinted fiber, and a relative selectivity coefficient k' of 10.40 for Mel with respect to its structural analog 2,4-dinitroaniline. MIF-Mel showed higher affinity to Mel with the maximum adsorption capacity of 15.5 mg g(-1), while that on nonimprinted fiber was only 6.9 mg g(-1). Its adsorption isotherm was well described using Langmuir model. Kinetic studies showed a rapid-binding interaction and high affinity of the MIF-Mel for its template, with a 2.5 times higher in binding amount and 4.7 times faster in binding speed than those of granular molecular-imprinting polymer with the same chemical structure. High degree of fitness with pseudo-second-order model revealed chemisorption was the rate-controlling step in the template-binding process. Basic theory of matrix-template interaction in this imprinting system was clarified to be dominated by electrostatic force synergized by hydrogen bonding between deprotonated carboxyl groups and protonated N atom in the template. It suggests that extension of this novel approach or theory to other imprinting system involving nitrogenous templates is very likely.