Study On The Synthesis And Properties Of Two Cardanol-based Benzoxazine

Benzoxazine is widely used owning to its superior performance. But recent years, the shortage of world resources limit the development of benzoxazine. Natural product cardanol not only is widely source but also has variety excellent properties. In order to expand the application fields of cardanol, in this thesis, unsaturated cardanol was used to react with different amine sources to synthesize cardanol-based benzoxazine resin, and study their properties.The aniline type of cardanol-based benzoxazine(BOZ-A) and hexamethylenedia-mine type of cardanol-based benzoxazine(BOZ-H) were synthesised by using solvent method. The structures of the two monomers were characterized by FTIR and1HNMR. Under atmospheric pressure, the density and viscosity of the two monomers were measured by using the Ostwald-Sprengel-type pycnometer and Ubbelohde capillary viscometer at303-338K. Based on experimental data, the formula of density and viscosity for BOZ-A with temperature were been determined as p=-0.5792T+1169.1202and η=10.590+1.8179×1011exp(-T/14.1407).The formula of density and viscosity for BOZ-A with temperature were been determined as p=-0.5238T+1128.3706and η=132.0714+8.0033×1016exp(-T/8.9876).The two monomers’s curing behavior and kineticses were studied by non-isothe-rmal DSC test method. Firstly, the radical polymerization reaction of double bond in aliphatic long chain induced under the action of radical initiator, then, benzoxazine carried out ring-opening polymerization. The catalysis effect of two monomers’s curing were most obvious when the catalyst was monoethanolamine(MEA) and its content was8%. The curing kinetics factors were calculated, the activation energy of BOZ-A、BOZ-H、BOZ-A+8%MEA and BOZ-H+8%MEA were106.06kJ/mol,95.78kJ/mol,69.17kJ/mol,83.90kJ/mol; the pre-exponential factor were5.94×1097.40×108,3.68×108,9.25×107; the reaction order were0.92,0.92,0.89,0.91.Curing the two monomers of BOZ-A and BOZ-H by temperature-programmed method to synthesize two cardanol-based benzoxazine resins:PBOZ-A and PBOZ-H. The two cardanol-based benzoxazine resin’s curing exothermic peak enthalpy at different temperature were studied by DSC test method, two monomers werecompletely cured at513K. Comparing the FTIR spectras of the monomers and resinsdetermined that two kinds of monomers BOZ-A and BOZ-H had been successfullycarried out ring-opening curing. The water contact angle of PBOZ-A and PBOZ-Hwere measured by contact angle meter as92.06oand93.42o, two kinds of reinsshowed hydrophobic. The cross-sections of PBOZ-A and PBOZ-H were investigatedby SEM. The resin’s cross sections had no bubbles and low porosity. PBOZ-H wasbrittle fracture.The thermal stability of PBOZ-A, PBOZ-H, PBOZ-A+8%MEA and PBOZ-H+8%MEA were studied by TG test. The char yield of resins were22%,16%,19%,15%;the temperature heat index were467.3K,467.6K,473.5K,467.8K. And PBOZ-A’sthermal stability was better than PBOZ-H’s.The thermal decomposition kinetics of PBOZ-A was studied by TG test. Thethermal decomposition activation energy of PBOZ-A was calculated by Kissingermethod, Starink method and FWO method, the calculated result of FWO hasmaximum correlation coefficient and minimum relative error, and the apparentactivation energy was175.97kJ/mol. The thermal decomposition reaction order wascalculated by using the Crane equation, the result was0.95, the thermaldecomposition reaction of PBOZ-A was a pseudo first order reaction.