Polystyrene cellulose fiber composites: effect of the processing conditions on mechanical and dynamic mechanical properties

Abstract

The usage of natural fibers on the composites development has grown rapidly in the recent years due to the fibers plentiful availability, renewable source, low density and biodegradability. However, there are some drawbacks, for instance, the fiber dispersion on a polyolefin matrix. In this work, the influence of processing speed on the mechanical and dynamic mechanical properties of polystyrene (PS) filled with cellulose fiber composites was investigated. The composites were processed on a twin-screw co-rotating extruder, using screw speeds of 200 rpm, 400 rpm and 600 rpm. The dynamic mechanical properties and the mechanical properties were investigated as a function of fiber content. The composites processed on a screw speed of 400 rpm had presented an increase on flexural and impact strength, compared to the composites processed at 200 rpm. The flexural and storage modulus had increased when increasing the fiber content, as well as increasing the processing speed. The greater fiber dispersion obtained at a screw speed of 400 rpm hinders the agglomeration arrangement and distributes the fibers more equally on the matrix. The increase on processing speed probably generates a fiber size reduction, increasing the fiber superficial area and generating a greater contact with the matrix as well. Therefore, the efforts transference of matrix to fibers is improved, originating an increase on the evaluated properties.

Studies on Mechanical Performance of Wood-Plastic Composites: Polystyrene-Eucalyptus globulus Labill

“…6). This behavior may be related to the fact that the cellulose fibers have a greater flexion modulus than the polymer matrix (Bengtsson et al 2007;Le Baillif and Oksman 2009;Poletto 2016), and also can be because of the orientation of the wood particles, which are perpendicular to the applied force. Table 3 shows the results of the impact tests.…”

“…The presence of agglomerates or clusters (Fig. 8c) promotes incompatibility with a hydrophobic polymer matrix reducing the composite mechanical properties (Le Baillif et al 2009;Poletto 2016) bioresources.com Flores-Hernández et al (2017). "WPC performance," BioResources 12(3), 6392-6404.…”

Statistical analysis of the substitution of inorganic fibers and fillers with vegetable fibers and fillers in polystyrene composites

“…In recent years, the utilization of fibers and powders derived from agricultural sources (such as banana, sisal, pineapple, wood, and cellulose) has become a subject of interest in polymer composites, mainly because of the above-mentioned advantages. 6,7 Wood powder is the most widely used vegetable reinforcement in polymer composites because of its abundance and ease of processing. In tropical countries, fibrous plants are available in abundance, and kapok fiber, which has a high cellulose content and naturally hydrophobic structure, may be interesting for use in polymer composites.…”

“…These vegetable reinforcements can be used in either powder or fiber form. In recent years, the utilization of fibers and powders derived from agricultural sources (such as banana, sisal, pineapple, wood, and cellulose) has become a subject of interest in polymer composites, mainly because of the above‐mentioned advantages 6,7 . Wood powder is the most widely used vegetable reinforcement in polymer composites because of its abundance and ease of processing.…”