Chemical Modification of Olive Pomace by Various Esters and Silane Aida Rabouhi, 1 Amar Boukerrou, 1 Mustapha Kaci, 1 Hocine Djidjelli, 1 J. J. Martinez-Vega 2 1 Laboratoire des Mate ´riaux Organiques, Universite ´ A.MIRA, Be ´jaia 06000, Algeria 2 Laboratoire LAPLACE, Universite ´ Paul Sabatier, Toulouse 31000, France Received 1 April 2008; accepted 3 September 2009 DOI 10.1002/app.31603 Published online 1 December 2009 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: The olive pomace was modified chemically to improve the interface between the polymer matrix and the cellulosic fillers. The modification was done using vari- ous ester types having the same nature, however, with dif- ferent chain lengths and one silane. Before the surface treatment, the olive pomace was extracted with acetone to remove contaminants on the surface, using Soxhlet appara- tus. The transesterification of olive pomace with the differ- ent ester components, i.e., vinyl acetate, vinyl propanoate, and vinyl butanoate, and the condensation reaction with dichlorodimethylsilane was confirmed by Fourier transform infrared (FTIR) analysis. Moreover, the treatment of olive pomace with vinyl acetate improves the thermal stability and the sample records higher onset temperature of degra- dation as measured by thermogravimetric analysis (TGA). The results obtained indicated also that the reaction between the hydroxyl groups of waste flour and the acetyl, propionyl, pivalyl, and silane groups have occurred. The modified wood flours exhibited a decrease in the hydrophi- licity as supported by the lower moisture content. V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 535–540, 2010 Key words: olive pomace; chemical modification; thermal stability; FTIR; thermogravimetric analysis INTRODUCTION Polymer composites are a special group of compos- ite materials produced by combining organic poly- mer resins with different kinds of filler materials. Natural composites have gained significant popular- ity in the last decade. The use of waste materials as a lightweight and eco- nomical source of reinforcement in thermoplastic composites has received substantial interest in scien- tific literature. 1–3 The advantages of natural fillers over traditional reinforcing materials, such as, glass fibers, talc, and mica are acceptable specific strength properties, low cost, low density, high toughness, good thermal properties, reduced tool wear, reduced dermal, respiratory irritation, and biodegradability. 4–6 However, the primary disadvantages are (a) poor interfacial adhesion and dispersion in olefin thermo- plastic matrix materials due to hydrophilic character of cellulose, (b) high moisture absorption leading to dimensional instability, and (c) low permissible tem- peratures of processing and use due to their limited thermal stability. 5 The hydrophilic groups present in unmodified cellulose are detrimental to the perform- ance of the cellulose based composites if the fibers are exposed to the outside atmosphere. Water, in liquid or vapor form, can diffuse into the composite, and the properties undergo deterioration. Also, the processing temperature for cellulose based reinforced composites is limited to 200  C, though higher temperatures can be used for short periods of time. 2 Wood-plastics composites are a novel class of materials with a myr- iad of applications owing to their versatility. Proper- ties of fillers reinforced composites are largely deter- mined by three factors: fiber content, fiber aspect ratio, and fiber orientation. Modifying agent is the subject of this study. During the past two decades, several methods have been reported in the literature for improvement of the ad- hesion between the filler and the thermoplastic matri- ces. Many papers have been published about the effect of chemical treatments on composite proper- ties. 1,2 Many studies concerned the thermoplastic matrices, such as, polypropylene, the coupling agents, such as, maleic anhydride, maleated polyethylene, or polypropylene, and the fillers used like the wood flour. This study is aimed to improve the interface between the matrix and the lignocellulosic material. Some chemical filler treatments have been carried out in order to ameliorate the interfacial adhesion between the filler and the matrix. Chemical modifi- cation of olive pomace with vinyl acetate, vinyl pro- pionate, and vinyl butanoate substitutes the cell wall hydroxyl groups with acetyl, propionyl, pivalyl, and Correspondence to: H. Djidjelli (hocdjidj@yahoo.fr). Journal of Applied Polymer Science, Vol. 116, 535–540 (2010) V C 2009 Wiley Periodicals, Inc.