SSRG International Journal of Polymer and Textile Engineering (SSRG-IJPTE) – Volume 7 Issue 2 – May - Aug 2020 ISSN: 2394 - 2592 www.internationaljournalssrg.org Page 25 Formulation of Anti-Corrosive Alkyd Paints Based on Umuahia Clay Extender Isaac O. Igwe*, Florence N. Acha, Christian O. Anyaegbu, Glory I. Agwu, Victor C. Ifeacho, Wisdom C. Esinwoke, Gospel S. Asiegbu and Chinedu Nwapa. Department of Polymer and Textile Engineering, Federal University of Technology, Owerri, Nigeria Abstract Umuahia clay was used as an extender to formulate alkyd paints possessing anti-corrosive property on mild steel. The clay which was sieved to 0.075 mm particle size was used within extender contents, 0 to 80.0 wt.%. Titanium dioxide prepared alkyd paint served as the reference paint while xylene was used as the solvent. Determinations on the properties of clay gave the following results: pH (6.50), specific gravity (2.10), oil absorption (36.0 g/100 g), and refractive index (1.63). The clay was stable to heat and the chemical media studied, and composed largely of silica (60.90 wt.%), alumina (24.63 wt.%) and titanium dioxide (3.50 wt.%). Other metallic oxides are present in negligible amounts. The formulated paints exhibited satisfactory surface -, and through- dry times, and the paint sample containing 80 wt.% clay had the best through-dry time of 216 min. The film thickness of the paint dry films were within 0.10 to 0.15 mm, an indication that the films will form barriers resistant to weathering. The formulated paint samples had good impact strength and the dry paint film hardness was observed to increase with increasing clay content. The paint samples containing 60, and 80.0 wt.% clay had maximum pencil hardness of 5H. The adhesion of the paint dry films to mild steel surfaces was generally good, and adhesion losses were in the range, 3.0 to 25.0 %. The paint dry films exhibited no blistering or severe paint defects on immersion in 3% NaCl except for slight colour changes which are suggestive of anti-corrosive property of the paints. The performance of the dry paint films in deionized water, and 3% Na 2 CO 3 , was generally satisfactory unlike the performance in 3% H 2 SO 4 where some paint defects occurred. The present study has highlighted the utility of Umuahia clay in formulating paints for the protection of mild steel in salty environments, the property which is attributed to the presence of inert oxides of silica, alumina, and titanium dioxide in the clay. Keywords: Alkyd Paints, Umuahia Clay, Extender, Titanium Dioxide, Particle Size. I. INTRODUCTION Clay is a common name for a number of fine grained earthly materials that are plastic and tenacious when moist, and permanently hard when fired or baked. Generally, clays are hydrated silicates of aluminium that approximate in composition to Al 2 O 3 .2SiO 2 .2H 2 0 and which may contain impurities such as potassium, sodium, calcium, magnesium or iron in small quantities. They are one of the major minerals that are abundant on the earth’s crust which are characterized by sheet silicate structures of composite layers stacked along the c – axis [1]. Clay minerals were envisaged to have been formed at different times in the geochemical cycle by the gradual weathering of rocks (usually silicates) by low concentrations of carbonic acid and other diluted solvents. Beside the weathering process, clay minerals are also formed by hydrothermal activity [2]. Clays appear in different colours ranging from dull grey to deep orange red depending on the soil content. The physical properties of clays such as hardness, cohesion, plasticity, and shrinkage under drying, can vary widely [3]. These common characteristics derive from their chemical composition, layered structure, and size. Generally, all clay minerals have great affinity for water and the ability to exchange ions[4]. Clays are used in a number of applications that depend on their qualities. They are utilized in the manufacture of industrial products such as paper, rubber, tiles, porcelains, white wares, and bricks. The clay, bentonite is used for cracking operations in the refineries [3], [5-6]. Fuller’s earth is utilized in the processing of many minerals, and vegetable oils [7]. Recently, Rahim et al [8] used montmorillonite clay to enhance the thermal degradation property of polyacrylonitrile / nano composite filaments. It was also reported that fibres with increased concentration of montmorillonite clay exhibited higher crystalinity. The use of clays as extenders in the formulation of paints is receiving attention from paint formulators and technologists who are searching for technically viable extenders that will partially or wholly replace titanium dioxide (TiO 2 ), the prime pigment used in surface coatings and thus, bring down the cost of paintings to acceptable limits. TiO 2 , a white pigment with high refractive index is the most widely used pigment in paint formulations. However, the pigment is very expensive because of its mineral origin. Worse still, TiO 2 is chemically active leading to photocatalytic degradation of painted surfaces [9]. Most of the extenders such as talc, whiting, and barytes used in paint production are expensive due to their mineral origin, and they require long processing with significant loss of materials [10]. Coating extenders are cheaper than the primary pigments.