149 Citation: Enyiegbulam ME, Iheaturu NC. Effect of Spent Oil Base Drilling Mud Solids on the Mechanical Properties of UPR Composites. Journal of Polymer Engineering. 2007;27(2):149–63. Doi:10.1515/polyeng.2007.27.2.149 http://www.degruyter.com/view/j/polyeng.2007.27.2/polyeng.2007.27.2.149/po lyeng.2007.27.2.149.xml EFFECT OF SPENT OIL BASE DRILLING MUD SOLIDS ON THE MECHANICAL PROPERTIES OF FILLED UPR COMPOSITES *Enyiegbulam, M. E. and Iheaturu, N. C. Dept. of Polymer & Textile Engineering, Federal University of Technology, Owerri. Imo, Nigeria enyiegbulaman@yahoo.com, nnamdi234@yahoo.com ABSTRACT Drilling mud solid content was recovered from spent oil base drilling mud (SOBM) samples collected from a rig site in Bonny Island, Rivers State, Nigeria. The mud solids (clays) were sieved into different particle sizes and calcined at 900°C for 2hrs, then treated with 40% ethylamine at 120°C. Solids in spent oil base drilling mud constitute about 55.65% per 100mls. Particle size analysis show that recovered spent mud sample contains about 77.48% of particles with size less than 300μm. The samples were complexed into unsaturated polyester (UPR) resin composite using the in-situ formation technique. Tests carried out on the samples show that 63μm, 75μm, 100μm, 300μm and 425μm filled composites gave modulus of 1666.67 x 10 6 Nm -2 , 312.5 x 10 6 Nm -2 , 156.25 x 10 6 Nm -2 , 125 x 10 6 Nm -2 and 104.2 x 10 6 Nm -2 respectively. Ultimate strength was 39.38 x 10 6 Nm -2 , 43.75 x 10 6 Nm -2 for 63μm and 75μm filled composites respectively and remained 37.5 x 10 6 Nm -2 for 100μm, 300μm and 425μm filled composites. UPR composite filled with 63μm size SOBM solids gave material with the highest modulus, resulting to improved tensile properties. Keywords: Spent Oil Base Drilling Mud (SOBM), Clay, Calcination, Unsaturated Polyester Resin (UPR), Methyl Ethyl Ketone Peroxide (MEKP), Nanocomposites, Microcomposites.