Methacrylate/acrylate terminated derivatives of diglycidyl hexahydrophthalate: Synthesis, structural, and thermal characterization

摘要

Mono- or di(meth)acrylate-terminated derivatives of diglycidyl hexahydrophthalate (ER) were prepared by reacting 1:1 or 1:2M ratio of ER and methacrylic acid or acrylic acid. These vinyl ester (VE) resins were characterized by determining epoxy equivalent weight, acid number, and molecular weight by gel permeation chromatography. Structural characterization was done by FTIR and H-1 NMR spectroscopy. In the H-1 NMR spectra of acrylate-terminated VE resins, three proton resonance signals were observed in the region 5.8-6.4 ppm due to vinyl group while in methacrylate-terminated VE resins only two proton resonance signals due to vinylidene protons were observed at 5.6-6.1 ppm. The Brookfield viscosity (room temperature (25 +/- 2)degrees C) of these resins diluted with varying amounts of MMA was determined at 20 rpm. Curing behavior was monitored by determination of gel time and differential scanning calorimetry. An exothermic transition was observed in the DSC scans in the temperature range of (81-150)degrees C. Isothermal curing of MMA-diluted VE resins containing AIBN as an initiator was done at 60 degrees C for 2 h in N-2 atmosphere, and then heating for another 2 h in static air atmosphere. Thermal stability of isothermally cured resins in N-2 atmosphere was evaluated by thermogravimetric analysis. All cured resins decomposed above 310 degrees C in single step. Thermal stability of the cured resins having acrylate end caps was marginally higher than the resins having methacrylate end groups. (c) 2005 Wiley Periodicals, Inc.