(407b) Reinforcement of Nylon-6 with Synthesized Porous Silica Nanoparticles

Self-assembled surfactant microstuctures can be used as templates to produce inorganic fillers using the principles of colloid and surface science. In this case, irregularly shaped large pore silicas were synthesized and were then mixed with nylon-6 using melt compounding on a DSM 5 twin screw micro-compounder. These silica nanoparticles are synthetic, versus native reinforcing nanoparticles such as montmorillonites which tend to contain trace quantities of Fe and Ti, leading to degradation of certain polymers at melt temperatures. The expected benefit of compounding these nanoparticles then is polymer stability, once dispersion has been achieved. Further, the synthetic process has been shown to produce anisotropic silica nanowires with potential as a good reinforcing agent. The composite was injection molded, and were tested for tensile modulus to determine initial levels of reinforcement these synthetic inorganic nanoparticles might contribute. The tensile tests showed a decrease in the elastic modulus as % filler is increased. The cores of the injection molded bars was then imaged using transimission electron microscopy. Clusters were noted, i.e. complete breakup and dispersion of the nanoparticles was not initially achieved, though fracture sites on the film showed good adhesion between the nylon-6 matrix and the silica nanowires. Mechanism for modulus decrease is postulated to be due to early fracture of the cluster.