Mechanical, Thermal and Rheological Properties of Polypropylene/Wheat Straw Composites and Study of the Effect of Nanoclay on Their Mechanical Properties

Abstract

Polymer–wood fibre composites utilize wood fibres as reinforcing filler in the polymer matrix and are advantageous over the pure polymers in terms of the materials cost and some mechanical properties such as modulus and strength. The scope of the present paper is to study the prospects of using wheat straw fibres as a reinforcing filler in polypropylene (PP). Untreated and silane-treated fibres having a variety of fibre lengths were used at various fibre contents to reinforce PP. Composites were tested for their mechanical, thermal and rheological properties, and the assessment of the adhesion at the interface was made via observations by SEM microscopy. The results showed that for untreated fibres, an increase in fibre content up to 20% (wt) led to an increase in the tensile strength of the composite. However, beyond this amount, tensile strength decreased. On the other hand, the tensile modulus increased due to higher stiffness of the fibres. By using silane treated fibres, both tensile strength and modulus increased, but the viscosity was reduced because of better dispersion of the treated fibres. By the addition of nano-clay, the mechanical properties of the composites, compared to the pure polymer, increased up to a certain fibre content, and after that the trend was reversed.

The effect of coupling agent on the mechanical properties of injection molded polypropylene/wheat straw composites

“…The explanation for the composites with and without coupling agent exhibiting very similar modulus values can be explained by the fact, that the quality of adhesion does not play a crucial role at low levels of mechanical loads, in which stage the Young's modulus is determined. Similar findings were also reported in the literature dealing with PP/WS composites containing straw particles of various size and concentration [29]. Interestingly, Ashori et al…”

Novel polylactide/triticale straw biocomposites: Processing, formulation, and properties

“…The thermal characterization revealed the formation of some intermolecular bonds between the polyester matrix and the lignocellulosic filler surface . Alternatively, the wheat straw surface treatment in combination with coupling agents in hydrophobic polyolefin composites, were found to be essential for the enhancement of tensile and flexural properties .…”

Synergistic Effect of Cellulose Nanofiber and Nanoclay as Distributed Phase in a Polypropylene Based Nanocomposite System

“…Several studies on the preparation of PP-based composites using cellulose filler and nanoclays, such as bamboo fiber [ 15 ], wheat straw fiber [ 16 ], wood flour [ 17 ], and microcrystalline cellulose (MCC), have already been reported [ 18 , 19 ]. In addition, CNFs are frequently used to form nanocomposites with nanoclay in poly(lactic acid) (PLA) [ 20 , 21 , 22 , 23 ] and paper matrix [ 4 ], leading to hydrophilic polymers.…”