The Morphology and Properties of Poly(methyl methacrylate)-Cellulose Nanocomposites Prepared by Immersion Precipitation Method Farah Fahma, 1,2 Naruhito Hori, 1 Tadahisa Iwata, 1 Akio Takemura 1 1 Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan 2 Department of Agroindustrial Technology, Bogor Agricultural University, Kampus IPB Darmaga, Bogor, Indonesia Correspondence to: A. Takemura (akiot@mail.ecc.u-tokyo.ac.jp) or F. Fahma (farah_fahma@yahoo.com) ABSTRACT: Poly(methyl methacrylate) (PMMA)-cellulose nanofibers nanocomposite were prepared by an immersion precipitation method using various nanofiber contents. Solvent exchange was used to disperse the cellulose nanofibers in dimethylacetamide (DMAc) so that they could be easily mixed with PMMA solution. Atomic force microscopy images show that the thickness of the nanofibers dispersed in DMAc is around 2–3 nm. The nanocomposites obtained were translucent. The thermogravimetric and differ- ential scanning calorimetry analyses show that with increasing cellulose nanofiber content the thermal stability and the glass transition temperature (T g ) of polymer matrix shift to higher temperature. The tensile modulus and strength increased with increasing nano- fiber content. Dynamic mechanical analysis profiles show that the presence of cellulose nanofibers affects the storage modulus of PMMA nanocomposites over the whole range of temperatures studied. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 000: 000–000, 2012 KEYWORDS: nanocomposites; nanoparticles; nanowires and nanocrystals; reinforcement Received 26 April 2011; accepted 4 July 2012; published online DOI: 10.1002/app.38312 INTRODUCTION Cellulose nanofibers as reinforcement in nanocomposites are a relatively new area of interest. This is because the use of cellu- losic fibers as reinforcing phase in nanocomposites has attracted the attention of many researchers around the world, such as low cost of the raw material, renewable nature, low density, wide variety of sources available in the world, high specific properties, modest abrasivity during processing, and biodegrad- ability. The main drawback of cellulose fibers for reinforcement applications is incompatibility with non-polar polymer matrices due to their hydrophilic nature. 1 Agglomeration is a common problem when hydrophobic polymers are filled with cellulose nanofibers. This phenomenon causes the worse adhesion between cellulose nanofibers and polymer matrix. Agglomera- tion usually occurs during the blending. Among available natural fibers, oil palm empty-fruit-bunch (OPEFB) is a very abundant, inexpensive, and renewable resource. OPEFBs are considered as waste after the extraction of oil palm fruits. With production reaching around 20 million tons of crude palm oil (CPO) in 2010, Indonesia is the major producer of CPO in the world. Each ton of CPO produces 1.1 ton of OPEFBs and causes a serious impact on the environ- ment. 2 In our previous work, we succeeded to isolate cellulose nanofibers from OPEFB which was highly dispersed in water. 3 Therefore, it is a major challenge how to obtain good cellulose nanofibers dispersion in hydrophobic polymer matrix. Some researchers have improved the dispersion of cellulose nanofibers in polymer matrix such as coating of the surface of cellulose nanofibers with surfactants 4,5 and dispersing cellulose nanofibers in non-water solvent without any surface chemical modification or coating surfactant. 6–8 Kim et al. 4 coated cellulose nanofibers obtained by HCl hydroly- sis of Whatman cellulose filter paper with the non-ionic surfac- tant (sorbitan monostearate) in order to improve the adhesion of cellulose nanoparticles to the hydrophobic polymer matrix (poly- styrene, PS). The surfactant appeared to enhance the dispersion of nanofibers within a PS matrix. Moreover, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) pro- vided evidence of the plasticizing effect of surfactant on the com- posite films, reducing the glass transition temperature (T g ). Sequeira et al. 1 argued that this strategy is not promising because high quantities of surfactant are required to obtain highly dispersed nanofiber suspensions in polymer matrix (in general, several times higher than the quantity of cellulose nanofibers). Poly(methyl methacrylate) (PMMA) is hydrophobic, hard glassy amorphous plastic, and has low water sorption ability. PMMA V C 2012 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM WILEYONLINELIBRARY.COM/APP J. APPL. POLYM. SCI. 2012, DOI: 10.1002/APP.38312 1