| COPNA resin, a new type of thermosetting resin, was first synthesized from condensed aromatic compounds and 1,4-benzenedimethanol in 1986. The COPNA resin has a 3-dimensionalnetwork structure. The aromatic rings are connected by methylene groups. Thus COPNA resin exhibits strong heat resistance, good rub resistance and affinity for carbon material. Bamboo tar is a kind of by-products from pyrolysis of bamboo. It has the similar properties with coal tar and asphalt tar. So bamboo tar can be used to synthesize COPNA resin.In our experiment, bamboo tar was first investigated by Gas Chromatography-Mass Spectrometric(GC-MS) and infrared absorption spectrum(IR) to study the composition of bamboo tar. Then COPNA resin was synthesized by bamboo tar,1,4-benzenedimethanol and p-toluene sulphonic acid. Theβresin was observed to find the optimal conditions of polymerization through orthogonal experiment method. The polymerization mechanism was study by IR of pre-recaction and post-reaction. Then thermo-gravimetric(TG) was used to analyze B-CONPA resin and cured COPNA resin under different temperature. From the results of TGA, the best cure condition of B-COPNA and the decomposition temperature of cured resin were obtained. IR was also used in cure process to study cure mechanism. Then COPNA resin was used as the matrix resin to create chopped carbon fibers/COPNA resin composites, which were investigated by mechanical property tests and Scanning Electron Microscope(SEM) to evaluate the mechanical property of resin. At last COPNA resin was carbonized after pore-making by Cu(NO3)2. The carbonization resin was prepare for anode material of lithium ion batteries to test the properties of COPNA resin as functional material.The analysis of GC-MS and IR showed that bamboo tar was mainly constituted by phenols, heteroatom compounds and a small quantity of polycyclic aromatic hydrocarbons. Analysis of P-resin of orthogonal experiment indicated that when the ratio of bamboo tar to 1,4-benzenedimethanol at 2:1, p-toluene sulphonic acid at 5% and temperature at 130℃, mostβresin could be obtained after 4h reaction. The peak value of number average molecular weight from Gel Permeation Chromatog-raphy (GPC) was about 1400 according with the meaning ofβresin. IR of reactants and products indicated that the mechanism of polymerization was condensation reaction with Lewis acid as catalyst.TG analysis of B-COPNA resin and cured resin under different temperature indicated that the best cure temperature was 80℃for 2h and 200℃for 2h. The decomposition temperature of cured COPNA resin was about 350℃. In addition, there was no quality loss before decomposition. Infrared absorption spectrum of B-COPNA and cured resin showed that cross-linking reaction occurred in aromatic rings between unreacted cross-linking agent and COPNA resin in cure process.The interlaminar shear strength(ILSS) tests on different amounts of unoxidized and oxydic carbon fibers indicated ILSS of composites increased with the increase of carbon fibers. When the proportion of carbon fiber was 30%, the maximum ILSS were 17.1Mpa of unoxidized fiber composite and 20.79Mpa of oxydic fiber composite. Cross-section SEM images of composites showed that COPNA resin exhibited good affinity with carbon fibers after oxidation. In addition, the composites had strong heat resistance from TG analysis.Carbon material derived from COPNA after pore-making by Cu(NO3)2 had wide pore size distribution from 0.1μm to 1μm. Lithium ion batteries test indicated that the first discharge capacity was 686.1mA·h/g. After 20 cycle, the charge/discharge capacities were stable at 291.5 mA·h/g. According to resistivity tests, doping of carbon nanotubes could decrease the resistivity of COPNA resin clearly. The resistivity of CNTs/COPNA resin composites could achieve 0.77Ω·cm at the nanotubes mass ratio of 5%. It was consistent with the requirement of conductive polymer materials. |
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