Preparation And Properties Of R-122/ SiO₂ Nanocomposite

Dicyclopentadiene dioxide is an important alicyclic epoxide, with excellent high temperature electrical properties, it has performance of resistance to leakage traces, arc, UV-resistant, radiation, even resistance to environmental conditions change, so it is a special epoxy resin material with excellent comprehensive Performance, and has been applied in many fields. However, the impact strength of dicyclopentadiene dioxide is low and its oughness is poor, which restrict its application, so it is of great significance to do something to improve the toughness of the nano-composites.In this paper, dicyclopentadiene dioxide nano-composite materials had been prepared the first time by the method of blending, then its mechanical and thermal properties were tested. First, the acrylic acid reaction with the dicyclopentadiene dioxide generated the acrylate, then the nano-SiO2 particles of different quality which is treated by silane is dispersion to the system, composites are got through curing. Seen from the IR image, the ring opening reaction has occurred between acrylic acid and dicyclopentadiene dioxide. The best ratio of n (acrylic acid):n (dicyclopentadiene dioxide) is 2:1; the mechanical properties of composite materials has improved compared with pure resin, when the amount of nano-SiO2 is 4%, the impact strength of composite materials to achieve the maximum value of 17.91 J/m,72.54% higher than the pure resin,these indicating that the nano-SiO2 with excellent toughening effect. Secondly, we studied the curing accelerator agent, curing agent, curing temperature, curing temperature program as well as the types of nanoparticles, and the best result is when the use of glycerol as a curing accelerator agent, and maleic anhydride as curing agent, curing the maximum temperature 200℃, curing temperature program was:90℃/2 h+120℃/2 h+160℃/2 h+200℃/6 h, nano-SiO2 particles as doping, the best mechanical properties of composite materials is got. Under optimal conditions, afert the reaction of dicyclopentadiene dioxide and maleic anhydride, glycerol, used ultrasound, high-speed shearing machine the different percent of the pretreated nano-SiO2 particles were dispersed into it, then we tested its mechanical properties, cross section scanning, thermal performance. The results show that:the mechanical properties of the composite materials have been greatly improved, were lonely increased by 128%,153%,192%,252%, and 183%, when the mass fraction of nano-SiO2 is 4%, the impact strength values of composites reached the maximum 36.57 J/m; what can be seen from the SEM pictures is the fracture of the pure resin is clear line liked, while the composite material is complex scaly, so it can absorb more impact energy; seen from TGA curve the thermal stability of the composite materials has been greatly improved than the pure resin. Finally, through reaction the MDI and the PPG2000 get prepolymer first, then formation of interpenetrating networks with dicyclopentadiene dioxide, and finally dispersed nano-SiO2 particles into it, get the composite materials, the mechanical properties of composite materials is tested. The results show that the impact strength of the composite materials is good, when the mass fraction of nano-SiO2 is 3%, the impact strength reached 41.63 J/m.