Plasma treatment application to improve interfacial adhesion in polypropylene‐flax fabric composite laminates

Abstract

Recently, due to environmental and sustainability issues, the scientific community has been attracted to renewable natural resources, even for the development of materials intended for structural applications. This work deals with the pre‐treatment of a flax fiber fabric by exploring the effects of the exposure time to nitrogen plasma on the ultimate performance of polypropylene matrix composite laminates potentially usable for the realization of internal parts in the naval sector. Flax fabrics were treated with three different exposure times (5, 10, and 15 min) with the aim to improve the adhesion between the hydrophilic fibers and the hydrophobic matrix. At first, transverse and longitudinal wicking tests were carried out on the treated fabrics in order to evaluate the improvement of the absorption constants after the formation of reactive groups on their surface. The results collected so far in terms of fabric water uptake, tensile, and flexural properties as well as morphological aspects (SEM analysis) and damage evolution (ESPI technique), have indicated that the optimal pre‐treatment time of the reinforcing fabrics is equal to 15 min. Compared to the laminate with untreated fabrics, the specimen with flax fibers treated for 15 min displays higher tensile properties with an increase of 6.8% and 22.31% in ultimate strength and modulus, respectively. More in general, the achievements of this research might be useful to extend the current range of applications of flax fibers even in industrial fields still dominated by conventional fibers.

Improved interfacial bonding strength of silicone rubber/carbon fiber modified by dopamine

“…In the recent years, researchers have conducted much scientific studies on the surface modification of CF to improve the interfacial bonding of CFRP composites. These methods include various wet and dry oxidation treatments, electrochemical oxidation, [ 11,12 ] plasma treatment, [ 13–15 ] corona discharge, [ 16 ] electron beam irradiation, [ 17–19 ] fast atomic beams, [ 20 ] acid oxide etching, [ 21 ] and UV‐initiated grafting. [ 22 ] In addition, nanofillers such as nanoclay, carbon nanotubes, graphene oxide, and other fillers can be added to the matrix.…”

“…These methods include various wet and dry oxidation treatments, electrochemical oxidation, [11,12] plasma treatment, [13][14][15] corona discharge, [16] electron beam irradiation, [17][18][19] fast atomic beams, [20] acid oxide etching, [21] and UV-initiated grafting. [22] In addition, nanofillers such as nanoclay, carbon nanotubes, graphene oxide, and other fillers can be added to the matrix.…”

Characterization of biobased epoxy resins to manufacture eco‐composites showing recycling properties

“…[ 6–8 ] However, the irreversible and crosslinked state of cured thermoset resin makes them unsuitable for recycling and causes significant effort in recovering the fibers and resins. [ 9–11 ]…”

“…[6][7][8] However, the irreversible and crosslinked state of cured thermoset resin makes them unsuitable for recycling and causes significant effort in recovering the fibers and resins. [9][10][11] The existing approaches include the introduction of labile linkages such as carbonate bonds, ester bonds, acetal bonds, Schiff base, and sulfur-containing structures to the thermoset resin. [12][13][14] Hongwei et al [15] developed degradable epoxy by introducing an aromatic disulfide bond.…”

Effects of temperature distribution caused by energy accumulation on the bonding properties of carbon fiber composite components

“…For the given substrate and adhesive, enhancing the interface is the key to improve the bond strength of joints. [10][11][12] Various surface modifications including grinding, [13] coupling agent coating, [14] laser treatment [15][16][17] and plasma treatment [18,19] have been used to improve the bonding property of CFRP components. Among these methods, cold plasma treatment is widely used because it can act on the depth of about 100 nm on the substrate surface exposed to the energy field, offering the possibility of surface chemical and physical modifications, but does not damage the substrates.…”