engleski

Molecularly Imprinted Crosslinked Copolymers Prepared by Thermal Degradation of Poly(Methacryl-N, N'-Diisopropylurea-co-Ethylene Glycol Dimethacrylate)

Molecular imprinting of desired molecules into selected solid crosslinked copolymers has attracted a large attention during the last few decades. Of special importance is that the molecular imprinting has been successfully applied to create recognition sites which due to their shape and the rearrangement of the functional groups have the affinity to the selected analytes. Two processes are usually applied for the preparation of molecularly imprinted copolymers. In one process, the analyte molecule is mixed with monomers not being covalently bounded, while in the other case the imprint molecules are covalently bounded with monomers. In both cases the main difficulty is the removal of print molecules after the copolymerization, since even a small amount of residual swellable print molecules causes the irregularities of the imprinted structure of polymer matrix. In a recently published paper (1) we have described the syntheses of nanoporous poly(acryl-N-cyclohexylamide-co-ethylene glycol dimethacrylate) by thermal decomposition of poly(acryl-N, N-dicyclohexylurea-co-ethylene glycol dimethacrylate) under the removal of volatile cyclohexylisocyanate. In continuation of our studies on the preparation of new herefore underscibed molecularly imprinted crosslinked copolymers, in this short communication we wish to describe a part of our work on the preparation of nanoporous crosslinked poly(methacryl-N-isopropylamid-co-ethylene glycole dimethacrylate) (poly(Methacryl-iPrA-co-EDMA)). The starting material was N-methacryl-N, N-diisopropylurea (Methacryl-DiPrU) prepared by the condensation of methacryl acid with diisopropylcarbodiimide. Methacryl-DiPrU was copolymerised with ethylene glycol dimethacrylate (EDMA) at a molar ratio of 0.5 to 0.5 of comonomers in the feed for 48 hrs at 700C in butanone in the presence of 1% of dibenzoyl peroxide as initiator. The reaction mixture was extracted with butanone, yielding 67.5% of crosslinked copolymer, which contains 3.51% of nitrogen, thus indicated that copolymer contains 25.3% of Methacryl-DiPrU. Copolymer decomposes by thermogravimetric analysis in nitrogen by a two step mechanism under the separate of isopropyldiisocyanate in the region of 180 C to 250 C. The nanoporous crosslinked poly(Methacryl-iPrA-co-EDMA) was prepared by thermal degradation od poly(Methacryl-DiPrU-co-EDMA) at temperature of 220-240 C in vacuum. After the separation of isopropylisocyanate, the thermaly stable nanoporous poly(Methacryl-iPrA-co-EDMA) which decompose by one step mechanism without the residue, was obtained. The schematic presentation of the thermal decomposition of poly(methacryl-DiPrU-co-EDMA) under the separation of isopropylisocyanate and formation of nanoporous Methacryl-iPrA in the copolymer matrix is presented in the Scheme 1. Scheme 1 It is evident from the Scheme 1, that the removal of volatile isopropylisocyanate forms nanoporous templates containing (NH-CO) as recognition groups. ______________________________ 1. A.Erceg Kuzmić, R.Vuković, G. Bogdanić, D.Fleš: Synthesys of Nanoporous Crosslinked Poly(acryl-N-cyclohexyl amide-co-ethylene glycol dimethacrylate) by Termal Degradation of Poly(acryl-N, N-dicyclohexylurea-co-ethylene glycol dimethacrylate), J.Macromol.Sci., -Pure Appl.Chem., 40(8), 747-754, 2003.

Molecularly Imprinted Crosslinked Copolymers

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