Progress in Organic Coatings 76 (2013) 1549–1555 Contents lists available at ScienceDirect Progress in Organic Coatings jou rn al hom ep age: www.elsevier.com/locate/porgcoat The formulation and study of the thermal stability and mechanical properties of an acrylic coating using chicken eggshell as a novel bio-ﬁller M.C. Yew a,∗ , N.H. Ramli Sulong a , M.K. Yew a , M.A. Amalina b , M.R. Johan b a Department of Civil Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia b Department of Mechanical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia a r t i c l e i n f o Article history: Received 17 May 2012 Received in revised form 20 June 2013 Accepted 23 June 2013 Available online 2 August 2013 Keywords: Acrylic resin Bio-ﬁller Calcium carbonate Coating Eggshell a b s t r a c t The objective of this study was to evaluate the effect of chicken eggshell (ES) as a bio-ﬁller on the adhe- sion strength and thermal stability of acrylic coatings. The inﬂuence of different particle sizes of ES on the performance of acrylic coatings was compared with commercial calcium carbonate ﬁller by using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and pull-off type equipment. The surface morphologies of the coatings were characterized through ﬁeld emission scanning electron microscopy (FESEM). The resistance of the coating was also investigated using water immersion and freeze–thaw tests. Morphological studies revealed that the ES ﬁller was well-distributed in the poly- mer matrix. Furthermore, it was observed that the adhesion strength, thermal properties, water and freeze–thaw resistance of the coating improved with decrease in particle size of ES ﬁller. Overall, the best results were obtained from using ES bio-ﬁller with the smallest particle, although the particle size was bigger than that of commercial calcium carbonate. The improvement in the properties of the coating was attributed to the even distribution of ES particles and better ES/matrix interface. © 2013 Elsevier B.V. All rights reserved. 1. Introduction The effective utilization of chicken eggshell (ES) biowaste is strongly encouraged in our society for environmental and eco- nomic reasons. ES which is a byproduct of the aviculture industry has been highlighted recently because of its reclamation potential. Unfortunately, most ES waste is discarded in landﬁlls without fur- ther processing. It is known that eggshell waste contains valuable organic and inorganic components which can be utilized in com- mercial products by creating new value in these waste materials. This study presents a useful bio-ﬁller derived from ES waste and its potential role in the coating industry. The properties of ES have been extensively studied for various purposes by many researchers. It consists of two materials: the calciﬁed eggshell made of calcite and calcium carbonate crystals and the ES membrane consisting of organic matter. ES contains about 95% calcium carbonate in the form of calcite and 5% organic ∗ Corresponding author at: Department of Civil Engineering, Faculty of Engineer- ing, University of Malaya, Lembah Pantai, Kuala Lumpur 50603, Malaysia. Tel.: +60 3 79676884; fax: +60 3 79675318. E-mail addresses: yewmingchian@siswa.um.edu.my, yewmingchian@gmail.com (M.C. Yew), davidyew1983@gmail.com (M.K. Yew), amalina@um.edu.my (M.A. Amalina), mraﬁej@um.edu.my (M.R. Johan). materials such as type X collagen, sulfated polysaccharides, and other proteins [1–11]. Although there have been several attempts to use ES components for various applications [12–19], its chemical composition and availability makes ES a potential source of ﬁller for polymer composites. Much attention has been given to the study of bio-ﬁller reinforced bio-polymer composites [20] and its applica- tion as coating pigments for ink-jet printing papers [21]. Besides its chemical composition, ES is a potential source of bio-ﬁller for coatings because it is available in bulk quantity, inexpensive, lightweight and environmental friendly. The major components of coatings are the binder and ﬁller combined with other additives. Several groups have reported the inﬂuence of particle morphology, ﬁllers, dispersing agents and nature of the binder material on the performance of coatings [22–28]. The binder forms a continuous phase that provides the main characteristics (e.g. mechanical, chemical) to the coating, while the ﬁller is the discontinuous phase giving additional or improved properties to the coating. The selection of the speciﬁc components will affect the general performance of the coating. The compatibility between ﬁller and binder is a key factor to improve the mechanical properties of the coating. Addition of ﬁller decreases the tendency of degradation of the system due to external factors like water ingress [29]. This paper focuses mainly on the effect of different types of ﬁllers and particle sizes on the thermal stability and mechanical 0300-9440/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.porgcoat.2013.06.011