Effect of Mechanical Treatment on Morphology and Thermal and Mechanical Properties of Sugar Cane Bagasse–Low-Density Polyethylene Composites Tshwafo Motaung, 1 Mokgaotsa Mochane, 2 Thollwana Makhetha, 2 Setumo Motloung, 3 Thabang Mokhothu, 1 Teboho Mokhena, 1,2 Rantooa Moji 2 1 CSIR Materials Science and Manufacturing, Polymers and Composites Competence Area, Nonwovens and Composites Research Group, Summerstrand, Port Elizabeth 6000, South Africa 2 Department of Chemistry, University of the Free State (Qwaqwa Campus), Phuthaditjhaba 9866, South Africa 3 Department of Physics, University of the Free State (Qwaqwa Campus), Phuthaditjhaba 9866, South Africa Sugar cane bagasse (SB)–low density polyethylene com- posites with different mechanically treated SB were pre- pared by a melt compounding method. The effect of the different treatments using supermasscolloider at low content of SB on the morphology, mechanical proper- ties, and thermal behavior was investigated. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy indicated that the dis- persion, crystallinity, and bonding of SB fibers depend on number of the treatments. The high modulus of SB generally improved tensile modulus of low-density polyethylene linearly and is proportional to supermass- colloider treatments. All composites show that the elon- gation at break was fairly constant within experimental error. Thermal stability decreased in the presence of SB and linearly increased in respect to the treatment times. The melting temperature decreased at lower passes. However, at higher passes, there was a marginal change. POLYM. COMPOS., 00:000–000, 2015. V C 2015 Society of Plastics Engineers INTRODUCTION The substitution of metallic materials by polymeric materials is a growing trend, especially when increased resistance to corrosion, low thermal and electric conductiv- ity, and low density are required [1–3]. Petroleum-based polymeric materials, on the other hand, lead to concerns in terms of both economic and environmental sustainability. Natural fibers reinforced-polymer composite is an example that revealed a potential to respond on environmental sus- tainability and economy. These composites have currently gained more attention because of their apparent biodegrada- tion, low density, high specific properties, availability, and mechanical characteristics [4–7]. The commonly used natu- ral fibers for polymeric reinforcements include banana, flax, hemp, kenaf, and sisal, which are also used in some applications, including cords, in most marine industries and for ornamental purposes [8, 9]. On the other hand, the use of biomass seemed to supplement natural fibers because of the substantial amount of cellulose contained and resultant mechanical properties when incorporated in polymeric mat- rices. One of the highly available biomass in Republic of South Africa, particularly in Kwa Zulu Natal province, is sugar cane bagasse (SB), the fibrous lignocellulosic remains after crushing and extraction process of the juice from sugar cane. It contains cellulose (46.0%), hemicellu- lose (24.5%), lignin (19.95%), pectin and waxes (3.5%), ash (2.4%), silica (2.0%), and other elements (1.7%) [5, 9]. The SB is traditionally used as a source of fuel and cellu- lose for paper production [10, 11]. Recently, a large number of researchers concentrate on the utilization of SB as an essential reinforcement for dif- ferent polymeric materials [12–16]. For instance, Yong et al. [12] studied composites based on recycled high- density polyethylene and maleic anhydride modified SB through melt blending and compression molding. Some researchers showed an interest on extraction of cellulose from the bagasse before incorporating it in high-density polyethylene by a melt mixer [3, 14]. For an automotive industry application, Cerqueira et al. [13] and Luz et al. [15] used injection molding to incorporate SB in polypro- pylene. Raj et al. [16] studied the correlation between the Correspondence to: T.E. Motaung; e-mail: TEMotaung@csir.co.za Contract grant sponsor: Green Fund (DBSA, DEA, CSIR). DOI 10.1002/pc.23717 Published online in Wiley Online Library (wileyonlinelibrary.com). V C 2015 Society of Plastics Engineers POLYMER COMPOSITES—2015