Study On Mechanics Properties Of SiO₂ Nanoparticle Modify Nylon 6

With development of the nano-technology, utilizing inorganic nano-particles to modify the behavior of polymer become a research hot spot in recent years. Nano-composite can significiantly improve some properties of the matrix material. By filling of SiO₂ nanoparticle, the strength and ductility of the nylon 6 material can be enhanced, which greatly increases its applications. How-ever, available studies on material properties are carried out under quasi-static conditions, and the actuall materical may bear dynamic even explosive loads in most cases. Therefore there is a strong need to detailedly understand effects of the nanoparticle on strengthen and toughen and carry out research on its mechanism in a larger range of the strain rate(from quasi-static conditions to impact loads).In frontal chapers, we carry out experimental studies on SiO₂/nylon 6 material(the volume content of SiO₂ is 0%,1%,2%,3%). Firstly, we employ MTS to do low strain rate test and use available split Hopkinson pressure bar(SHPB) and modified split Hopkinson Tensile Bar(SHTB)to do high strain rate compressive and tensile tests respectively. We study its mechanical properties from quasi-static conditions to impact loads(the range of strain rate 10-3/s¹03/s). Then, we employ scanning electron microscope(SEM) and X-ray diffraction meter(XRD)to study the distribution of nanoparticle in matrix and the crystallization after filling of SiO₂. Then, the study focuses on the effect of strain rate and the influence of nanoparticle content on the mechanical properties of matrix.The results show that the yield strength is raising with strain rate increasing, rigidity and elastic modulus, and the breaking elongation firstly increases and then decreases with content of the nano SiO₂. The mechanics properties are better when the volume fractions of nanoparticle are low. If the content of nanoparticle is too high, the properties of the material become poor.In the six chapter, the theoretical discussions are carried out. Based on macro mechancis properites of the material measured in experiments, the interface structure between SiO₂ nanoparticle and nylon 6 is proposed, and eventually, the available mechanicsm of nanoparticle strengthening and toughening is discussed.