Enhancing the mechanical performance of 3D‐printed basalt fiber‐reinforced composites using in‐line atmospheric plasma pretreatments

Abstract

The objective of this study is to investigate the use of an air atmospheric plasma jet for the treatment of sized basalt fibers, used in the fabrication of continuous fiber‐reinforced polypropylene filaments. The plasma treatments were carried out both at a laboratory scale, as well as in‐line during the production of fiber‐reinforced filaments. The latter was carried out at a fiber processing speeds of approximately 15 m/s, just immediately before the polymer coating of the fiber by extrusion. After the air plasma treatment, the water contact angle of the sized basalt fiber decreased from 86° to <10°. X‐ray photoelectron spectroscopy analysis demonstrated that the treatment yielded enhanced levels of oxygen functionality on the fiber surface. After coating with polypropylene, it was observed that there was consistently more homogeneous polymer layer deposited onto the plasma‐activated fiber, compared with that on the unactivated control fiber. The resulting polymer filament with embedded basalt fiber was used to fabricate mechanical test specimens by three‐dimensional printing (fused filament fabrication method). Both three‐point bending tests and short beam strength tests were performed. A comparison study was carried out between test specimens fabricated using sized basalt fiber, with and without the plasma pretreatment. The flexural modulus and maximum shear stress were found to increase by 12% and 13%, respectively, for composite's fabricated using the plasma pretreated basalt fibers. This increased mechanical strength is likely to be due to an increase in interfacial bond strength between the polymer and fiber, with an associated reduction in the level of air incorporation around the basalt filaments as demonstrated using computed tomography analysis.

3D Printing of Fibre-Reinforced Thermoplastic Composites Using Fused Filament Fabrication—A Review

“…Typical short fibres used as reinforcements include carbon and glass fibres. Recently, basalt fibre has also received attention [ 25 ].…”

“…Another method of both decreasing the porosity of the FFF printed parts, as well as enhancing interlayer adhesion, is the use of atmospheric plasma surface activation treatments. This was demonstrated through the use of an in-line air atmospheric plasma jet treatment for the activation of sized basalt fibres, immediately prior to the application of polypropylene by extrusion coating, to form the polymer-coated filaments [ 25 ]. The flexural modulus and the maximum shear stress values of the resulting FFF composites were found to increase by 12% and 13%, respectively, compared with those obtained for composites fabricated using untreated fibres.…”

Basalt Fiber Composites with Reduced Thermal Expansion for Additive Manufacturing

“…In this regard, the surface functionalization of the fibers has been performed via chemical modification with maleic anhydride [ 20 , 25 , 30 ], silane coupling agents [ 31 , 32 , 33 , 34 ] or with inorganic acid and bases [ 35 , 36 , 37 ]. Plasma treatment has also been used for surface functionalization [ 38 ]. The use of these strategies has reported improvements in the mechanical properties of the composites.…”

Enhanced thermal stability and impact strength of phenolic formaldehyde resin using acid‐treated basalt scales

“…Such a lamellar structure in polymer-based composites can play a strong reinforcing role that significantly enhances the thermal and mechanical properties of the composites. [13][14][15][16][17] The interfacial interactions between an inorganic filler and a polymer matrix are a key factor affecting the performance of the resulting polymer composites. Generally, BS aggregates in a polymer matrix due to poor compatibility between BS and the polymer matrix, resulting in a deteriorated performance of the composites.…”

“…When the size reaches several hundred microns, BS exhibits a very high diameter‐to‐thickness ratio. Such a lamellar structure in polymer‐based composites can play a strong reinforcing role that significantly enhances the thermal and mechanical properties of the composites 13–17 . The interfacial interactions between an inorganic filler and a polymer matrix are a key factor affecting the performance of the resulting polymer composites.…”