Study On Synthesis And Characterization Of Novel Multifunctional Epoxy Resin

Multifunctional epoxy resin has the characteristics of high reactivity, high crosslinking density, and the cured multifunctional epoxy is of excellent heat-resistance, which attracts extensive attention. In this paper, a kind of triphenol,4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-1-benzopyran-2-yl)-1,3-benzenediol was synthesized by using deionized water as solvent and resorcinol and acetone as monomers. Furthermore, a novel multifunctional epoxy resin was synthesized by reaction of the triphenol and epichlorohydrin (ECH), which had not been reported yet. The curing behavior and kinetics of the multifunctional epoxy were investigated by various analytical methods.A novel synthesis system was invented by using deionized water as solvent in which the multiphenol with high purity and high yield was obtained. The result of yield calculation and HPLC analysis showed that4-(3,3-dihydro-7-hydroxy-2,4,4-trimethyl-2H-1-benzopyran-2-yl)-1,3-b enzenediol reached99.2%in yield and94.35%in purity. It was much higher than those reported in references. Analysis results of different scanning calorimetries (DSC) and thermal gravimetric analysis (TGA) showed that the melting temperature(Tm) of triphenol was223.4℃and melting range was from197.4℃to228.9℃.A novel tri functional epoxy resin (TF-EPOXY) was synthesized by the triphenol and ECH. The optimal experimental condition was determined by studying the influence of different factors in reaction, such as the amount and concentration of NaOH, the amount of ECH and types of catalysts. As a result, the maximum epoxide number of synthesized TF-EPOXY could reach0.636, which was99.2%of calculated value.The cure kinetics of TF-EPOXY was investigated by DSC and gelatinization time methods when it was cured by Diaminodiphenyl-sulfone (DDS), diaminodiphenylmethane (DDM),593, CYDHD-520, AIR1784,8410and Aradur3225, respectively. Following were the results. In TF-EPOXY/DDS system, activation energy (Ea) was63.98kJ/mol and reaction order (n) was0.885, while curing procedure was140℃/2h+200℃/2h+220℃/4h. In TF-EPOXY/DDM system, Ea was55.13kJ/mol and n was0.882, while curing procedure was140℃/2h+170℃/4h. In TF-EPOXY/593system, Ea was47.35kJ/mol. In TF-EPOXY/CYDHD-520system, Ea was26.32kJ/mol. In TF-EPOXY/AIR1784system, Ea was46.37kJ/mol. In TF-EPOXY/8410system, Ea was48.56kJ/mol. In TF-EPOXY/Aradur3225system, Ea was19.74kJ/mol.Heat-resistance performance of cured TF-EPOXY and CYD-128were investigated by dynamic mechanical thermal analysis (DMTA), DSC and TGA. Following were the analysis results. Tg of TF-EPOXY/DDS system was290.1℃, higher73.9℃than CYD-128/DDS system. Tg of TF-EPOXY/DDM system was240.2℃, higher60.1℃than CYD-128/DDM system. Tg of TF-EPOXY/593system was76.2℃, higher10.7℃than CYD-128/593system. Tg of TF-EPOXY/CYDHD-520system was117.2℃, higher19.9℃than CYD-128/CYDHD-520system. Tg of TF-EPOXY/AIR1784system was104.5℃, higher8℃than CYD-128/AIR1784system. Tg of TF-EPOXY/8410system was147.2℃, higher28.2℃than CYD-128/8410system. Tg of TF-EPOXY/Aradur3225system was95.2℃, higher18.2"C than CYD-128/Aradur3225system.The analysis of dielectric properties of a series of cured TF-EPOXY and CYD-128was carried out by Agilent4294A Precision impedance analyzer. Following were the results. Dielectric contant (εr) of cured TF-EPOXY changed slightly with the increase of current frequency; and the sequence of εr went as follows:TF-EPOXY/593>TF-EPOXY/AIR1784>TF-EPOX Y/C YDHD-520>TF-EPOX Y/8410>TF-EPOX Y/DD M>TF-EPOXY/DDS>TF-EPOXY/Aradur3225. Dielectric loss (tan8) of cured TF-EPOXY increased with enhance of current frequency, and the sequence of tanδ went as follows:TF-EPOXY/AIR1784>TF-EPOXY/CYDHD-520>TF-EPOXY/593>TF-EPOXY/8410>TF-EPOXY/DDS>TF-EPOXY/DDM>TF-EPOXY/Aradur3225.