Characterization of Rheological and Thermophysical Properties of HDPE–Wood Composite Mosfafa Tazi, 1 Fouad Erchiqui, 1 Franc ¸ois Godard, 1 Hamid Kaddami, 2 Abdellah Ajji 3 1 Universit e du Qu ebec en Abitibi-T emiscamingue,  Ecole de g enie, Rouyn-Noranda Quebec, Canada 2 Universit e Caddi Ayad Marrakech, Laboratoire ‘LCO2MC,’ B.P. 549, Marrakech 40000, Maroc 3 Chemical Engineering Department, Polytechnique, Montreal, Quebec, Canada Correspondence to: F. Erchiqui (E - mail: Fouad.Erchiqui@uqat.ca) ABSTRACT: The objective of this study is to develop a new biocomposite material with high deformation ability. In this regard, the thermal, rheological, and thermophysical properties of this new composite were characterized as a function of temperature and filler concentration. High density polyethylene (HDPE) was the matrix of this new composite which was reinforced with six sawdust con- centrations 0%, 20%, 30%, 40%, 50%, and 60%. Maleic anhydride grafted polyethylene (PE-g-MA) was used as coupling agent. Addi- tion of sawdust with PE-g-MA increased significantly the complex viscosity, the storage modulus (G 0 ), and loss modulus (G 00 ) of the matrix. The superposition of the complex viscosity curves using temperature dependent shift factor, allowed the construction of a vis- cosity master curve covering a wide range of temperatures. Arrhenius law was used for the relationship of the shift factor to tempera- ture. Furthermore, method of Van Gurp and Palmen (tan delta vs. G*) is also used to control the time–temperature superposition. The experimental results can be well fitted with the cross rheological model which allowed the prediction of the thermorheological properties of the composites over a broad frequency range. By increasing wood concentration, both the activation energy and relaxa- tion time for the biocomposites determined using, respectively, the Arrhenius law and the cole–cole rule increased. By contrast, spe- cific heat of the matrix decreased with sawdust addition while its dimensional stability improved. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40495. KEYWORDS: wood-polymer composites; rheological properties; thermal properties analysis Received 6 November 2013; accepted 21 January 2014 DOI: 10.1002/app.40495 INTRODUCTION Nowadays, due to the environmental and economic concerns, many research activities are directed toward the development of new composites based on thermoplastic matrices with plants (or their residues) reinforcement. 1 Reinforcement of composites with natural fillers has several advantages in comparison to mineral fillers including lower density, being inexpensive, and being non- abrasive. In fact, high cellulose component of natural fillers makes them easily biodegradable and recyclable. Also, cellulose fillers possess a crystalline structure which plays a positive role in the composite reinforcement. As a consequence many researchers are interested in the development of new techniques for extraction and modification of cellulose fillers from bioresources. 2 In addition, cellulose has a reactive functionality that can react with coupling agents thus enhancing adhesion between the fiber and the matrix. 3 Studies have also shown that the mechanical properties of composites are highly dependent on the interaction between the thermoplastic matrix and distribution of loaded fillers. 4 While this interaction is well established, the loading force will be transferred from matrix to fillers more effectively. On the other hand, the majority of modeling and simulating work of these biocomposites for their processing assumes con- stant thermal parameters of the materials, such as density and heat conductivity, or they do not take into account the special temperature dependency of the specific heat due to melting process. This is because the temperature dependence of these material parameters for biocomposites is not well understood sufficiently so far. Since the rheological and deformation behav- iors are strongly connected with the thermal behavior, it became obvious that these issues affect directly the accuracy of any sim- ulation or modeling result. In this regard this study attempts to focus on the effect of tem- perature and bio-reinforcement contents on dynamic rheologi- cal, thermal, and physico-chemical properties of thermoplastic matrix composites (high density polyethylene [HDPE]) and bio-reinforcement fillers (sawdust). V C 2014 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM J. APPL. POLYM. SCI. 2014, DOI: 10.1002/APP.40495 40495 (1 of 11)