Studies On The Synthesis And Curing Properties Of Silicon Functionalized Nornornane Dianhydride

The modification of epoxy resin by organic silicon effectively improved its high temperature resistance, but the problem is the poor compatibility. Organic silicon functionalized anhydride is a new curing agent, which has fine compatibility with organosilicon and epoxy resin. It could introduce Si-O-Si bond in crosslinking network when cured with epoxy resin. It has excellent thermal stability and physical properties than common curing agents.In this paper, 1,1,3,3-tetramethyldisiloxane (TMDS) and 5-norbornene-2,3-dicarboxylic acid anhydride (NA) was utilized to synthesize silicon functionalized nornornane dianhydride (SNA). FTIR, NMR, EI-MS, and single crystal X-ray diffraction were adopted to characterize the structure of the products and one of the byproducts,5,6-exo-(1,1,3,3-tetramethyldisiloxane-diyl)bicyclo-[2.2.1]heptane-endo-2,3-d icarboxylic anhydride. The curing reaction process of SNA and epoxy resin were studied by gel time and DSC methods. Kinetics data of curing reaction were calculated. The curing process was determined. The heat resistance of curing products and its influence were studied as well.The results show that5,6-exo-(1,1,3,3 -tetramethyldisiloxane-diyl)bicyclo-[2.2.1]heptane-endo-2,3-d icarboxylic anhydride was monoclinic, P2₁/n space group, a=8.0475(?), b=12.047(?), c=15.361(?),β=95.84°, Z=4. When the ratio of SNA and CYD-128 was 90 to 100, the gel time was the shortest. The curing reaction proceeded completely at the ratio 120 to 100. The curing process was 100℃/2h+150℃/2h+200℃/1h, the values of apparent activation energy and reaction order were 65.68kJ/mol and 0.898 respectively. When the ratio of SNA and CER-170 was 80 to 100, the gel time was the shortest. The curing reaction proceeded completely at the ratio 110 to 100. The curing process was 80℃/2h+120℃/2h+150℃/2h+220℃/2h, the values of apparent activation energy and reaction order were 87.3kJ/mol and 0.9226 respectively. The curing reaction rate was affected by the degree of functional group of the curing agent and epoxy resin, activity of functional group, content of accelerant. The temperature resistance of SNA cured epoxy resin sharply increased compared with epoxy resin cured by NA. The temperature resistance of SNA/BDMA/CYD-128 was the best within the range of experiment, its glass transition temperature was 143.48℃, the weight loss was 1.5% at 300℃. SNA could be dissolved in most common solvents, it has fine compatibility with epoxy resin and organosilicon.