| Cyanate ester resin, which is called in tha next, is a kind of thermosetting resin with excellent comprehensive performance. The three triazine ring in CE’s structure makes thermal properties, dielectric properties, abrasion resistance and water resistance favourable. At the same time, the simple molding process of CE is well known to researchers. Now it has been used in fields of aerospace, electron and printing. With the rapid development of science and technology, much higher demands for CE have been put forward, such as mechanical properties, water resistance, wear resistance and dielectric properties, in the technical field of modern application. PMMA/CE, nano particles/CE, nano-Nd2O3 with PMMA grafted on the surface/PMMA/CE have been preparated in the research. FTIR, SEM, DMA, TEM and DSC has been used to investigate the modified CE system. Experiments in this paper include:(1) PMMA prepolymer has a great influence on mechanical properties and surface of CE. The best processing parameters of PMMA/CE are determined with PMMA molecular weight of 60×104, pumping time of 75 min and PMMA mass fraction of 15wt%,when the pressure is-0.085 MPa. The tensile, impact and flexural strenght of PMMA/CE reach the max values, which is 54.48 MPa, 189.29 MPa and 16.98 k J/m2. If comparing with pure CE, these above indices increase by 35.32%, 64.29% and 85.37%. Where in the molecular weight of 60×104, preparation of PMMA prepolymer are as follows: the polymerization temperature is 85 ~ 90 ℃, initiator BPO added in an amount 0.1wt%.(2) The results of characterization of PMMA/CE show that the linear PMMA was cross-linked through chemical bonding molecule with the network structure of CE, connecting in series in the CE matrix and forming the semi-interpenetrating network;The appearance of PMMA increases the mechanical properties of modified CE. The storage modulus and the controllability of the curing reaction of PMMA/CE has been increased, while loss modulus and the exothermic peak temperature reduced.(3) Through the analysis of the crystal structure and crystalline phase of the surface-modified nanoparticles,conclusion can be drawn as follows: PMMA was successfully grafted onto the surface of nanoparticles, and generated a core-shell structure with an inorganic core and organic shell.The original crystalline of the nanoparticles has not been changed and achieve a organic surface in the base of inorganic particles. The surface energy of nanoparticles was reduced and the dispersibility of nanoparticles was improved.(4) As the modifier of CE, the nanoparticals was used to prepare Nd2O3/CE, nano-Nd2O3 modified by KH-560/CE, nano-Nd2O3 with PMMA grafted on the surface/CE nano-Nd2O3/PMMA/CE composite material with PMMA grafted on the surface. The mechanics performance testing of the four system shows that, compared with the pure CE, when the addition amount of Nd2O3 reaches 4wt%, the mechanical properties of gafted PMMA/PMMA/CE will achieve the best conditions. Also, the mechanical properties improve remarkably. The composite of M-2/PMMA/CE shows the best mechanical properties. The impact strength and bending strength were 15.64 k J/m2 and 150.23 MPa(5) By TEM, DSC and other characterization showed that Nd2O3 nanop- articles grafted on the surface of PMMA enhance the interface function of inorganic particles and organic polymer, improving the interfacial compatibility of the Nd2O3 nanoparticles and CE matrix, and did not change the CE curing reaction mechanism.(6) Performance test showed that: the thermal decomposition temperature of the pure CE is 365.92 ℃, bibulous rate is at 1.2%, the friction coefficient is 0.46, dielectric constant is 2.4, dielectric loss is 0.0118; The thermal decomposition temperature of PMMA/CE is 354.54 ℃, bibulous rate is 0.92%, the friction coefficient is 0.34, dielectric constant is 4.5, dielectric loss is 0.00761; The thermal decomposition temperature of the nano-Nd2O3 with PMMA grafted on the surface /PMMA/CE with nanoparticles grafted on the surface is 357.75 ℃, bibulous rate is 0.8%, the friction coefficient is 0.26, dielectric constant is 5.4, dielectric loss was 0.00524. Compared with the pure CE, the thermal stability of PMMA/CE and nano-Nd2O3 with PMMA grafted on the surface /PMMA/CE has been keeped, the water resistance and wear resistance has been improved. Dielectric constant increases, as well as the dielectric loss decreases.(7) Results show that the mechanics performance of nano-Nd2O3 with PMMA grafted on the surface /PMMA/CE is significantly improved, thermal stability has been keeped, and its water resistance, abrasion resistance and dielectric performance has also been enhanced. The improvement of its dielectric performance, will promote its application in the field of stealth materials, further broaden the CE application field. |
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