Performance of polyolefin composites containing recycled paper fibers

Abstract

An alternative process to the conventional melt compounding for the incorporation of paper fibers into polyolefins was developed, based on the dispersion of paper fibers in a hot polyolefin solution and the subsequent precipitation of the polymer by cooling, which leads to an homogeneous polyolefin/paper compound. The hardness, tensile and dielectric properties of composite specimens prepared by compression molding of the obtained compound, with filler content ranging from 0 to 40% (w/w), were examined. The tensile strength of the examined composites decreases especially in the case of high-density poly(ethylene) (HDPE) and poly(propylene) (PP) composites at relatively higher filler content. The modulus of elasticity was improved only for the low-density poly(ethylene) (LDPE) composites, in comparison with unfilled specimens, and this behavior is in agreement with the observed improvement in the hardness values of these composites. Dielectric spectroscopy has been used as a characterization method of the prepared composites. It was found that the addition of newspaper fibers to the polyolefins does not significantly affect the insulating properties of the materials. In conclusion, it seemed that polyolefin/paper fiber composites with acceptable properties can be prepared by the solution/precipitation technique studied in this work.

Dielectric properties of nanopowder emulsions in paraffin oil

“…The relative dielectric constant remains stable at a value of 2.13 for frequencies over 1 kHz. At frequencies below 100 Hz, κ΄ values decrease similarly to previous results for transformer oils [1] and/or other type of organic samples [12,13]. This response relates to the enhanced dielectric losses developing as a result of the dominating low-frequency polarizations.…”

Study of effect of old corrugated cardboard in properties of polypropylene composites: Study of mechanical properties, thermal behavior, and morphological properties

“…This leads to undesirable properties of the composites. It is therefore usually necessary to modify the fiber surface using compatibilizing and coupling agents before, or during, the compounding step to enhance the compatibility and adhesion between the components and improve the fiber dispersion in the matrix, thus improving as well the mechanical properties . Various chemical reagents have been used to enhance the compatibility between the constituent materials.…”

Recycled multilayer cartons as cellulose source in HDPE‐based composites: Compatibilization and structure‐properties relationships

“…6,7 Recently, the use of recycled cellulose to produce composites has been proposed, in some case with promising results. [8][9][10] However, it is well known that different surface properties between fiber (highly polar) and polymer matrix such as polyolefin (non-polar and hydrophobic) require the set up of a proper compatibilization strategy. Without such a strategy, weak interfaces are generated, likewise a poor ability of the polymer to completely wet fiber surface and consequently overall properties of the composite are almost substandard.…”