1. Introduction
There are more than 100 types of fillerdorganic or
inorganicdthat have been studied and reported in previous
literature [1,2]. However, not all of them are reinforcing
materials and some have limited usage. For instance, carbon
black and silica can act as reinforcing fillers but talc and
calcium carbonates can only be used for reducing the cost
of compound [3].
Oil palm ash (OPA) is the by-product from the combustion
of oil palm biomass and normally considered as
waste. In Malaysia, OPA is highly abundant and will be
disposed of or dumped in an open field. The large quantity
of OPA produced has contributed to the rapid increase in