Effect of Filler Particle Size on Dynamic Mechanical Properties of Poly (methyl methacrylate)

Abstract

Dynamic mechanical properties of poly (methyl methacrylate) (I) filled with glass beads (G) and mica (M) of various size have been investigated. Dynamic modulus E′ slightly decreases with the increase of particle size for I-G system, but E rapidly increases and then attains to the upper limitting value with the increase of particle size for I-M system. With increasing particle size, primary dispersion temperature (T_α) decreases for I-G system, but increases for I-M system. Effect of particle size on the modulus can be explained in terms of orientation of mica flakes by comparing the experimental data with Wu' and Padawer and Beecher's predictions of the modulus. The observed results of T_α have been analysed by using the equation T_α=K₁ ln K₂S, where S is a surface area of filler per gram of polymer matrix, and K₁ and K₂ are constants. It has been found that T_α is strongly affected by the surface area of the filler in the case of I-G system and affected also by the orientation effect in addition to the surface area of the filler in the case of I-M system.