Complex-Radical Copolymerization of Vinylcyclohexyl Ketones with Maleic Anhydride and N-p-tolylmaleimide

Some features of the formation and photochemical reactions of cyclohexylketone containing macromolecules including copolymers of vinylcyclohexyl ketone (VCHK) and its derivatives (V-a-Cl-CHK and V- d-C1-CHK) with maleic anhydride (MA) and N-p-tolylmaleimide (TMI) have been revealed. It has been established that keto-enol tautomerism is the only reaction realized in the vinylcyclohexylketone molecules having mobile hydrogen atom at a -position in the cyclohexane ring, enol form of which is formed by charge-transfer complexes with anhydride or imide of maleic acid as acceptor monomers. The kinetic parameters of these reactions, including complex-formation and copolymerization constants, as well as the ratios of chain growth rates for the participation of monomeric charge-transfer complexes and free monomers,В are all determined. It is shown that an alternative copolymerization is realized with the monomer systems containing VCHK and V- d -C1-CHK, which are carried out through a complex-mechanism due to the keto-enol tautomerism; while random copolymer enriched with vinyl ketone units is formed with the system containing oc-substituted VCHK. It is found that characteristics of photochemical reactions ofВ alternating copolymer synthesized depend on the type of substitutation in the vinyl ketone molecule; unlink VCHK-MA(TMI) and V-d-C1-CHK-MA(TMI) copolymers case which easily crosslink upon UVirradiation, and the N-substituted derivatives of these copolymers which decompose under similar condition

Plasma-Induced, Solid-State Polymerization of N-Isopropylacrylamide

The radio-frequency plasma-initiated polymerization of N-isopropylacrylamide (NIPAM) in the solid state was performed. The isolated linear polymer was characterized by C-13-NMR, H-1-NMR, and Fourier transform infrared spectroscopy, and the effects of selected operational plasma parameters (discharge power and time) on the conversion rates were studied. Reversible transitions at the volume-phase-transition temperatures of the swelled poly(N-isopropylacrylamide) hydrogels were investigated by differential scanning calorimetry. The surface morphologies before and after plasma treatment were followed by scanning electron microscopy. With the obtained X-ray diffraction results, we propose a solid-state plasma polymerization mechanism for the NIPAM. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 3311-3320, 201

Use of silane coupling agents to improve epoxy–rubber interface

Scrap car tyre particles can be used as filler or toughening agent in rigid epoxy matrices if the resultant interface is adequate. The objective of this work was to investigate the effects of use of different silane coupling agents (SCAs) to improve the interface between the epoxy resin and recycled rubber particles. For this purpose, seven different SCA were used to modify surfaces of the rubber particles. After the preparation of epoxy-rubber specimens, tensile Charpy impact and plane-strain fracture toughness tests were conducted. Mechanical tests and fractographic studies revealed that some of the SCA can improve of the interface between the epoxy matrix and the rubber particles leading to increases in strength while slight decreases in toughness of the samples