Preparation Technology Of DAP Resin At High Temperatures And Research On Its Glass Fiber Composites

Polymerized diallyl phthalate(DAP),a thermosetting resin with low dielectric constant,dimensional stability and good water,thermal and weather resistance,has many applications,such as the material for electron,construction,aeronautics and astronautics field and so on.Currently,radical polymerization,which has many disadvantages(low production,high energy consumption and pollution),is adopted to produce diallyl phthalate resin.In order to avoid those defects,the bulk polymerization at high temperature,which has advanced craft with less organic solvent and minimal impacting on the environment,is studied in this paper.And DAP polymer reaction mixture could be used as resin directly.Exploration research on vacuum assistant resin infusion of DAP resin has simplified the traditional molding process and tried to achieve green production.In this paper,the bulk polymerization is used to polymerize diallyl phthalate to prepolymer directly in the presence of DMDPB(free initiator) at high temperature.As a result,the percent conversion of DAP monomer rise up by 40%.And the temperature range of 190℃-220℃is proved to be suited,and DMDPB is used as a free initiator with a concentration of 0.5%,because DMDPB,which is alkyl hydrocarbon kind,is very stable in room temperature while compared to those peroxide or azo compounds.The kinetics study of polymerization of diallyl phthalate before gel point is carried out by measuring the value of monomer conversion ratio, when the concentration of free initiator is 0.5%.The reaction activation energy is 97.45 KJ/mol and the data fit the second-order reaction basiclly.The polymerization process of DAP monomer is studied through the characterization of DAP polymer reaction mixture by Fourier Transform Infrared Spectrometry(FTIR).In the investigation on viscosity,it can be concluded that the viscosity of DAP polymer reaction mixture,which is polymerized at high temperature,is basiclly fitted viscosity equation and its viscous flow activation energy is 46.05kJ/mol.The viscosity of DAP polymer reaction mixture,which is polymerized at high temperature, is high in the room temperature but moderate at the mesothermal surroundings (70-80℃).And the viscosity of the polymer reaction mixture,which is polymerized at high temperature,remains basically stable in half a year at the room temperature.The influence of polymerization temperature on the mechanical and thermal properties of DAP resin is studied by static mechanical property test,thermogravimetric analysis (TGA) and dynamic mechanical analysis in this paper.The characterization results indicate that the high temperature polymerization has no influence on the mechanical, thermal and thermolysis properties of DAP resin.The glass transition temperature range and thermolysis temperature range of DAP resin are 166.2～187.4℃and 285～296℃respectively,and both of them indicate that the DAP resin has excellent thermal and thermolysis properties.The DAP resin glass fiber composites,which is prepared with DAP polymer reaction mixture,is synthesized successfully by vacuum assistant resin infusion(VARI) method in this study.From the experimetal and characterization results,it can be concluded that the VARI is a simple and efficacious novel technology for the preparation of DAP resin glass fiber composites with much better mechanical properties.