Determination of the orientation of mica in composites

Abstract

A wide angle x‐ray diffraction technique has been used to determine the orientation of mica flakes in composites. The mica used was a fine grade Phlogopite, and the polymers were polystyrene, polycarbonate and poly(vinyl chloride). Composite samples of varying mica contents and orientations were prepared. The x‐ray method can give the orientation distribution function of mica flakes across and parallel to the surface of the sample. From this function, an average orientation parameter was calculated. The results show that there is no orientation of mica across the surface of the sample (the x‐ray beam is normal to the surface), but that there is a strong orientation in a direction parallel to this surface, the average orientation parameter being strongly dependent upon the particle size of mica and mode of preparation.

Molecular Dynamics of Poly(Ethylene Terephthalate)/Muscovite Mica Composite by Low-Field NMR

“…[1,2] When used as reinforcing filler in plastics, mica offers many advantages including planar reinforcement, reduced creep, and reduced wear of processing equipment. [3] The incorporation of mica into plastics is also known to increase the stiffness and to reduce the elongation at yield and at break, [4] resulting in apparently brittle materials. However, in practice, as the propagation of cracks originates from flaws that exist in most structures, the performance of mica-based composites is also dependent upon the filler degree of dispersion, morphology, and degree of interaction between mica surface and the polymer matrix.…”

Ageing and Weathering of Mica-SBR Composites

“…In the case of aged samples (Figures 3 and 4), orientation effect of mica is not detectable because it comes into play only at higher elongation [7,13].…”

Preferential orientation of muscovite in ceramifiable silicone composites

“…Due to the high aspect ratio of mica particles, it is likely that during processing such as polymer compounding and subsequent hot press curing, the flow that occurs could lead to orientation of the platelets within the polymer matrix. The degree of orientation of mica in polystyrene, polycarbonate and PVC has previously been quantitatively determined using wide-angle X-ray diffraction [22]. The degree of filler orientation within a polymer matrix may be estimated by calculating the ratio between characteristic peak intensities of (0 0 l) reflections and those of (h k l) reflections in XRD traces for oriented and non-oriented specimens [23,24].…”