Polymeric Coatings for AR-Glass Fibers in Cement-Based Matrices: Effect of Nanoclay on the Fiber-Matrix Interaction

Polymeric coatings are widely used to enhance the load bearing capacity and chemical durability of alkali-resistant glass (AR-glass) textile in cement-based composites. The contact zone between coated yarns and concrete matrix plays a major role to enable the stress transfer and has still to be improved for the full exploitation of the mechanical behavior of the composite. As a new approach, this paper studies how the addition of nanoclay particles in the polymer coating formulation can increase the chemical bond between organic coating and inorganic matrix. This includes the description of the water-based coating preparation by dispersing sodium montmorillonites, whereby the resulting coating nanostructure is characterized by X-ray diffraction and energy dispersive X-ray spectroscopy. Single glass fibers were treated by dip-coating. Atomic force microscopy was used to determine the surface roughness, and the effect on the fiber tensile properties was studied. Moreover, the morphological and chemical characteristics of the coatings were compared with the results obtained from single fiber pull-out (SFPO) tests. It was shown that the incorporation of nanoclays leads to increased interfacial shear strength arising from the ability of nanoclay particles to nucleate hydration products in the fiber-matrix contact zone.

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Graphene Deposition on Glass Fibers by Triboelectrification

Applied Sciences ◽

10.3390/app11073123 ◽

2021 ◽

Vol 11 (7) ◽

pp. 3123

Author(s):

Haroon Mahmood ◽

Laura Simonini ◽

Andrea Dorigato ◽

Alessandro Pegoretti

Keyword(s):

Graphene Oxide ◽

Interfacial Shear Strength ◽

Glass Fibers ◽

Deposition Process ◽

Solution Concentration ◽

Dip Coating ◽

Slight Improvement ◽

Reduced Graphene ◽

Fiber Matrix ◽

Positively Charged

In this work, a novel nanomaterial deposition technique involving the triboelectrification (TE) of glass fibers (GF) to create attractive charges on their surface was investigated. Through TE, continuous GF were positively charged thus, attracting negatively charged graphene oxide (GO) nanoparticles dispersed in a solution. The electrical charges on the glass fibers surface increased with the intensity of the TE process. The deposited GO coating was then chemically treated to obtain reduced graphene oxide (rGO) on the surface of GFs. The amount of coating obtained increased with the GO solution concentration used during the deposition process, as revealed by FESEM analysis. However, the same increment could not be noticed as a function of the intensity of the process. Both uncoated and coated GF were used to obtain single fiber microcomposites by using a bicomponent epoxy matrix. The fiber/matrix interfacial shear strength was evaluated through micro debonding tests, which revealed an increment of fiber/matrix adhesion up to 45% for rGO coated GF in comparison to the uncoated ones. A slight improvement in the electrical conductivity of rGO coated fibers through TE compared to conventional dip coating was also observed in terms of volumetric resistivity by a four-point probe setup.

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Tailored Interfaces in Fiber-Reinforced Elastomers: A Surface Treatment Study on Optimized Load Coupling via the Modified Fiber Bundle Debond Technique

Polymers ◽

10.3390/polym13010036 ◽

2020 ◽

Vol 13 (1) ◽

pp. 36

Author(s):

Julia Beter ◽

Boris Maroh ◽

Bernd Schrittesser ◽

Inge Mühlbacher ◽

Thomas Griesser ◽

...

Keyword(s):

Surface Treatment ◽

Fibrous Composite ◽

Glass Fibers ◽

Matrix Material ◽

Fiber Reinforced ◽

Component Level ◽

Adhesion Properties ◽

Surrounding Matrix ◽

Pull Out ◽

Fiber Matrix

The interface between the reinforcement and surrounding matrix in a fibrous composite is decisive and critical for maintaining component performance, durability, and mechanical structure properties for load coupling assessment, especially for highly flexible composite materials. The clear trend towards tailored solutions reveals that an in-depth knowledge on surface treating methods to enhance the fiber–matrix interfacial interaction and adhesion properties for an optimized load transfer needs to be ensured. This research aims to quantify the effect of several surface treatments for glass fibers applied in endless fiber-reinforced elastomers with pronounced high deformations. Due to this, the glass fiber surface is directly modified with selected sizings, using a wet chemical treatment, and characterized according to chemical and mechanical aspects. For this purpose, the interfacial adhesion performance between fibers and the surrounding matrix material is investigated by a modified fiber pull-out device. The results clearly show that an optimized surface treatment improves the interface strength and chemical bonding significantly. The fiber pull-out test confirms that an optimized fiber–matrix interface can be enhanced up to 85% compared to standard surface modifications, which distinctly provides the basis of enhanced performances on the component level. These findings were validated by chemical analysis methods and corresponding optical damage analysis.

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Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100154755 ◽

1989 ◽

Vol 47 ◽

pp. 556-557

Author(s):

K.L. More ◽

R.A. Lowden

Keyword(s):

Mechanical Properties ◽

Fracture Toughness ◽

Chemical Vapor ◽

Chemical Vapor Infiltration ◽

Frictional Stress ◽

Fiber Reinforced ◽

Pull Out ◽

Carbon Coated ◽

Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

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Fiber-matrix bond strength by pull-out tests on slag-based geopolymer with embedded glass and carbon fibers

Journal of Adhesion Science and Technology ◽

10.1080/01694243.2020.1870322 ◽

2021 ◽

pp. 1-11

Author(s):

Lais Alves ◽

Nordine Leklou ◽

Pascal Casari ◽

Silvio de Barros

Keyword(s):

Bond Strength ◽

Carbon Fibers ◽

Pull Out ◽

Fiber Matrix

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Poly N-(2-cyanoethyl)pyrrole as a selective film for the thickness-shear-mode acoustic wave sensor

Canadian Journal of Chemistry ◽

10.1139/v95-177 ◽

1995 ◽

Vol 73 (9) ◽

pp. 1427-1435 ◽

Cited By ~ 13

Author(s):

Zhiping Deng ◽

David C. Stone ◽

Michael Thompson

Keyword(s):

Acoustic Wave ◽

Photoelectron Spectroscopy ◽

Electrochemical Polymerization ◽

Shear Mode ◽

Polymeric Coatings ◽

Thickness Shear Mode ◽

X Ray ◽

Acoustic Wave Sensor ◽

Polypyrrole Film ◽

Thickness Shear

Poly N-(2-cyanoethyl)pyrrole films have been synthesized by electrochemical polymerization and characterized by cyclic voltammetry, scanning electron microscopy, and X-ray photoelectron spectroscopy. Polymeric coatings prepared on the surface of a thickness-shear-mode acoustic wave sensor have been used to examine response selectivity to a number of gas-phase probe molecules. The responses of the poly N-(2-cyanoethyl)pyrrole based sensor are compared with the parent polypyrrole device and rationalized in terms of the molecular interactions between probes and polymer films. The polar cyano functionality enhances interactions with analytes such as acetonitrile. Keywords: gas sensor, thickness-shear-mode acoustic wave sensor, poly N-(2-cyanoethyl)pyrrole film, polypyrrole film, conducting polymer.

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Dynamic Single-Fiber Pull-Out of Polypropylene Fibers Produced with Different Mechanical and Surface Properties for Concrete Reinforcement

Materials ◽

10.3390/ma14040722 ◽

2021 ◽

Vol 14 (4) ◽

pp. 722

Author(s):

Enrico Wölfel ◽

Harald Brünig ◽

Iurie Curosu ◽

Viktor Mechtcherine ◽

Christina Scheffler

Keyword(s):

Tensile Strength ◽

Dynamic Loading ◽

Melt Spinning ◽

Structural Changes ◽

High Surface ◽

Single Fiber ◽

Scanning Calorimetry ◽

Matrix Interaction ◽

Pull Out ◽

Fiber Matrix

In strain-hardening cement-based composites (SHCC), polypropylene (PP) fibers are often used to provide ductility through micro crack-bridging, in particular when subjected to high loading rates. For the purposeful material design of SHCC, fundamental research is required to understand the failure mechanisms depending on the mechanical properties of the fibers and the fiber–matrix interaction. Hence, PP fibers with diameters between 10 and 30 µm, differing tensile strength levels and Young’s moduli, but also circular and trilobal cross-sections were produced using melt-spinning equipment. The structural changes induced by the drawing parameters during the spinning process and surface modification by sizing were assessed in single-fiber tensile experiments and differential scanning calorimetry (DSC) of the fiber material. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle measurements were applied to determine the topographical and wetting properties of the fiber surface. The fiber–matrix interaction under quasi-static and dynamic loading was studied in single-fiber pull-out experiments (SFPO). The main findings of microscale characterization showed that increased fiber tensile strength in combination with enhanced mechanical interlocking caused by high surface roughness led to improved energy absorption under dynamic loading. Further enhancement could be observed in the change from a circular to a trilobal fiber cross-section.

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Scattering and phase-contrast X-ray methods reveal damage to glass fibers in endodontic posts following dental bur trimming

Dental Materials ◽

10.1016/j.dental.2020.10.018 ◽

2020 ◽

Author(s):

Ana Prates Soares ◽

Daniel Baum ◽

Bernhard Hesse ◽

Andreas Kupsch ◽

Bernd R. Müller ◽

...

Keyword(s):

Phase Contrast ◽

Glass Fibers ◽

X Ray ◽

Ray Methods

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Characterization of ordered mesoporous films on silicon (001) surface using X-ray and electron diffraction

Journal of Applied Crystallography ◽

10.1107/s0021889804031498 ◽

2005 ◽

Vol 38 (1) ◽

pp. 211-216 ◽

Cited By ~ 5

Author(s):

Pang-Hung Liu ◽

Kuei-Jung Chao ◽

Xing-Jian Guo ◽

Kuo-Ying Huang ◽

Yen-Ru Lee ◽

...

Keyword(s):

Electron Diffraction ◽

Sol Gel ◽

Dip Coating ◽

Silica Film ◽

Continuous Film ◽

X Ray ◽

Transmission Electron ◽

Ordered Mesoporous ◽

Direction Dependence

A continuous silica film with well aligned mesochannels parallel to the Si(001) surface was found to be formed through sol–gel dip-coating of a silica precursor with nonionic ethylene oxide surfactant. Two two-dimensional mesoporous structures in centered and non-centered rectangular symmetries and with the short axes of elongated ellipsoidal pores normal to the surface were observed by X-ray and electron diffraction. Detailed transmission electron microscopy investigations were employed to view the direction dependence of the channel or pore packing in the continuous film.

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