LAUSR

Polyacetal is widely used in thin walled injection moulding due to its high mechanical properties. But, its widespread application is limited due to volumetric shrinkage and warpage. The investigations on reducing warpage on Polyacetal is attempted by incorporating nano fumed silica of 1 wt% to 5 wt% as a nucleating agent. The crystallinity study shows that the crystallization rate is increased with the addition of fumed silica up to 4 wt%, beyond which it is reduced. The increased warpage and tensile strength are observed with increase in crystallinity. The tensile strength of PA/5 wt% FS nanocomposite is 1.79% lesser than PA/4 wt% FS nanocomposite, but still 2.5% higher than neat PA. The effect of the filler on surface roughness and optical properties such as haze and gloss are also studied. The micro voids are steadily increased as filler loading increases. Hence, the surface roughness increases uniformly upon increase of filler and it does not depend on crystallinity but depends on growth of micro voids. Furthermore, the microscopic analysis is carried out through FTIR, XRD and SEM and discussed. It is concluded from the above analysis that 5 wt% of FS loading into PA reduces warpage of the thin walled parts with a gain of mechanical strength than neat PA.