Electrically Conductive Fibre Composites Prepared from Polypyrrole-Engineered Pulp Fibres

Abstract

E lectrically conductive composite materials have applications such as electrostatic dissipation and electromagnetic shielding. They are manufactured by dispersing conductive fi llers such as metal particles, carbon black, graphite or carbon fi bres in a polymer matrix. With the increasing environmental awareness around the globe, materials that pose less threat to the environment are now receiving more and more attention from researchers and the industry.As a renewable natural resource with good mechanical properties, cellulose fi bre enjoys advantages over other polymeric materials in environmental friendliness. The previous work (Huang et al., 2005) (referring to the modifi cation of the bulk or surface properties of pulp fi bres to produce desired fi bre attributes (Baum, 2002)) by following the in situ chemical polymerization to deposit polypyrrole on fi bre surfaces so that the cellulose fi bres become electrically conductive. In addition, the processability of the intrinsically conducting polymer (ICP) was greatly improved through the versatile formability of the fi bre substrates. The small amount of ICP introduced will not have much impact on the overall biodegradability of the material.In this research work, electrically conductive paper composites were prepared from polypyrrole-engineered pulp fi bres by two methods: (a) exclusively from such engineered fi bres; and (b) from a mixture of the modifi ed fi bres and unmodifi ed ones. Both composites were investigated for their conductivity and strength properties as a function of monomer dosage or percentage of treated fi bres in the mixture. It was found that, for the "mixture" method (i.e., by adding treated fi bres as conductive fi llers), less monomer (i.e., conductive polymer) was needed to achieve the same conductivity while a higher tensile strength in the paper was attained when comparing with paper obtained exclusively from treated fi bres. The percolation model was adopted to describe such paper-conducting polymer composites, and the much lower percolation threshold achieved through the "mixture" method can be explained by a multiple-percolation theory. The long-term environmental aging stability of these composites was also monitored, and attempts were made to interpret the observed conductivity decay through existing kinetic models.Dans ce travail de recherche, des composites de papier électriquement conductifs ont été préparés à partir de fi bres de pâte traitées au polypyrrole par deux méthodes : (a) exclusivement à partir de fi bres traitées par cette méthode et (b) à partir d'un mélange de fi bres modifi ées et non modifi ées. Les deux composites ont été étudiés quant à leurs propriétés de conductivité et de résistance mécanique en fonction du dosage de monomères ou du pourcentage de fi bres traitées dans le mélange. On a trouvé que pour la méthode du « mélange » (en ajoutant des fi bres traitées comme agents de remplissage conductifs), on a besoin de moins de monomères (polymère conductif) pour atteindre la même conductivité, alors qu'un...

Toward Flexible Polymer and Paper‐Based Energy Storage Devices

“…Further, cellulose fiber length and fiber thickness as well as the degree of crystallinity of the cellulose are all anticipated to influence the tensile strength of the final conductive paper sheet. In order to improve the tensile strength of PPy‐cellulose sheets, it has been suggested to blend a fraction of the bare cellulose fibers with those coated with PPy while still retaining the overall conductive properties of the composite 137, 138…”

Percolation for Coated Conductive Paper: Electrical Conductivity as a Function of Volume Fraction of Graphite and Carbon Black

“…It has also been applied to the conductive paper system made of mixed, unmodified pulp fibers and modified polypyrrole pulp fibers, for which a threshold of 8.7 vol.% was found (Huang et al 2005;Li et al 2010b).…”

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