چكيده به لاتين
Abstract:
In this work, the effect of silica nanoparticles on the structure and curing of natural rubber foam were studied. also, the effect of coupling agent and conditions of mixing on the foam density and cell structure were studied. increasing the amount of silica nanoparticles due to increased shear viscosity and also the scorch time and curing time is reduces. It also increases the curing temperature, due to reduce the shear viscosity and curing reaction is accelerated. the blowing agent also dramatically affect on curing time and it reduces. On the other hand, the curing system also catalytic effect on the performance of blowing agent and decomposition temperature of bowing agent about 50°C is reduces. According to SEM images taken from NR foams can be find out that by increasing the composition of silica nanoparticles , Cell wall thickness increased , smaller cell size and cell structure of the foam produced is more uniform . Cell density of NR foam prepared with silica nanoparticles due to the effect nucleation of nanoparticles to the matrix rubber, increases. The average cell diameter of NR foam prepared with silica nanoparticles decreases, by increasing the amuont of silica nanoparticles because of the increased the cell walls of thickness, low volume fraction of the rubber matrix and space prevents the nanoparticles are created. Furthermore, by reducing the average cell diameter of the foams, also the number of cells per unit volume increases. With increasing curing temperature, the gas published in the rubber matrix increased, the cell wall thickness reduced and smaller cells are combined with each other which leads to production of lower cell density foam, average diameter cell larger and the number of cells per unit volume less. increasing the mixing temperature, due to a drop in molecular weight rubber matrix and the improved adhesion of silica nanoparticles into the rubber matrix, cell density reduced and average diameter cell increases. After the addition of coupling agent to system, due to increased adhesion between the silica particles and rubber matrix, gas produced in the rubber matrix possibility of withdrawing from the interface between the nanoparticles and the matrix rubber less and NR foam produced in this case has a lower density and average diameter cells were more.
Keywords: Natural rubber foam, Cell structure, Silica nanoparticles, Mixing temperature, Foaming temperature
