Submit to Materials Review for Materials Propose a Special Issue

Journal Browser

► Journal Browser

Polymer Composites and Interfaces

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Published Papers

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (31 October 2018) | Viewed by 29207

Share This Special Issue

Special Issue Editor

Dr. Uwe Gohs

E-Mail Website
Guest Editor

Department of Composite Materials, Leibniz Institut für Polymerforschung Dresden, 01069 Dresden, Germany
Interests: composite materials; fibers; interface/interphase; toughening; sustainable reactive processing

Special Issue Information

Dear Colleagues,

Composites provide enhanced mechanical properties and tailored multifunctionality. Their overall performance significantly depends on the structure and property of composite components in the region near their internal surface (interphase). These interphases are mostly smaller in thickness compared to the size of reinforcing fillers/fibers. Nevertheless, a change in their structure and chemistry leads to significant changes in their overall performance, especially under extreme operation conditions (corrosive environments, high moisture, low temperature, high strain rates, etc.). Consequently, the interphase has to be tailored in order to meet the requirements of static and dynamical properties, as well as multifunctionality and environmental resistance during the lifetime of composites. This Special Issue aims to highlight investigations on surface modification/characterization of fillers/fibers, new concepts/approaches for functional and/or self-healing interfaces/interphases in polymer composites, as well as characterization techniques and theories at different scales. Contributions are welcome on recent experimental and theoretical aspects aiming on understanding the effect of interface/interphase structure and structure of composite components on chemical, mechanical, physical and thermal properties, as well as on fracture mechanics of polymer composites at different scales. Reports of research studies on biomaterial based polymer composites using sustainable technologies are highly appreciated.

Dr. Uwe Gohs
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

polymer composites
characterization at different scales
theory at different scales
self-healing
sustainability

Published Papers (7 papers)

Download All Papers

Research

11 pages, 3503 KiB

Open AccessArticle

Mechanical Characterizations of 3D-printed PLLA/Steel Particle Composites

by Hozhabr Mozafari, Pengfei Dong, Haitham Hadidi, Michael P. Sealy and Linxia Gu

Materials 2019, 12(1), 1; https://doi.org/10.3390/ma12010001 - 20 Dec 2018

Cited by 8 | Viewed by 5184

Abstract

The objective of this study is to characterize the micromechanical properties of poly-l-lactic acid (PLLA) composites reinforced by grade 420 stainless steel (SS) particles with a specific focus on the interphase properties. The specimens were manufactured using 3D printing techniques due to its many benefits, including high accuracy, cost effectiveness and customized geometry. The adopted fused filament fabrication resulted in a thin interphase layer with an average thickness of 3 µm. The mechanical properties of each phase, as well as the interphase, were characterized by nanoindentation tests. The effect of matrix degradation, i.e., imperfect bonding, on the elastic modulus of the composite was further examined by a representative volume element (RVE) model. The results showed that the interphase layer provided a smooth transition of elastic modulus from steel particles to the polymeric matrix. A 10% volume fraction of steel particles could enhance the elastic modulus of PLLA polymer by 31%. In addition, steel particles took 37% to 59% of the applied load with respect to the particle volume fraction. We found that degradation of the interphase reduced the elastic modulus of the composite by 70% and 7% under tensile and compressive loads, respectively. The shear modulus of the composite with 10% particles decreased by 36%, i.e., lower than pure PLLA, when debonding occurred. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Figure 1

18 pages, 6718 KiB

Open AccessArticle

Flexural and Shear Strain Characteristics of Carbon Fiber Reinforced Polymer Composite Adhered to a Concrete Surface

by Hisham Jahangir Qureshi and Muhammad Umair Saleem

Materials 2018, 11(12), 2596; https://doi.org/10.3390/ma11122596 - 19 Dec 2018

Cited by 11 | Viewed by 5392

Abstract

The use of Fiber Reinforced Polymer (FRP) composites for strengthening concrete structures has gained a lot of popularity in the past couple of decades. The major issue in the retrofitting of concrete structures with FRP is the accurate evaluation of flexural and shear strains of polymer composites at the bonding interface of epoxy and concrete. To address it, a comprehensive experimental study was planned and carbon fiber reinforced polymer (CFRP) composite was applied on the concrete surface with the help of adhesives. CFRP was used as an external mounted flexural and shear reinforcement to strengthen the beams. Flexural load tests were performed on a group of eight reinforced concrete beams. These beams were strengthened in flexural and shear by different reinforcement ratios of CFRP. The strain gauges were applied on the surface of concrete and CFRP strips to assess the strain of both CFRP and concrete under flexural and shear stresses. The resulting test data is presented in the form of load–deformation and strain values. It was found that the values of strains transferred to the FRP through the concrete are highly dependent on the surface tensile properties of concrete and debonding strength of the adhesive. The test results clearly indicated that the strength increment in flexural members is highly dependent on strain values of the CFRP. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Figure 1

13 pages, 9576 KiB

Open AccessArticle

Enhanced Interfacial Shear Strength and Critical Energy Release Rate in Single Glass Fiber-Crosslinked Polypropylene Model Microcomposites

by Uwe Gohs, Michael Thomas Mueller, Carsten Zschech and Serge Zhandarov

Materials 2018, 11(12), 2552; https://doi.org/10.3390/ma11122552 - 15 Dec 2018

Cited by 4 | Viewed by 3499

Abstract

Continuous glass fiber-reinforced polypropylene composites produced by using hybrid yarns show reduced fiber-to-matrix adhesion in comparison to their thermosetting counterparts. Their consolidation involves no curing, and the chemical reactions are limited to the glass fiber surface, the silane coupling agent, and the maleic anhydride-grafted polypropylene. This paper investigates the impact of electron beam crosslinkable toughened polypropylene, alkylene-functionalized single glass fibers, and electron-induced grafting and crosslinking on the local interfacial shear strength and critical energy release rate in single glass fiber polypropylene model microcomposites. A systematic comparison of non-, amino-, alkyl-, and alkylene-functionalized single fibers in virgin, crosslinkable toughened and electron beam crosslinked toughened polypropylene was done in order to study their influence on the local interfacial strength parameters. In comparison to amino-functionalized single glass fibers in polypropylene/maleic anhydride-grafted polypropylene, an enhanced local interfacial shear strength (+20%) and critical energy release rate (+80%) were observed for alkylene-functionalized single glass fibers in electron beam crosslinked toughened polypropylene. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Graphical abstract

18 pages, 2492 KiB

Open AccessArticle

Why Should the “Alternative” Method of Estimating Local Interfacial Shear Strength in a Pull-Out Test Be Preferred to Other Methods?

by Serge Zhandarov, Edith Mäder and Uwe Gohs

Materials 2018, 11(12), 2406; https://doi.org/10.3390/ma11122406 - 28 Nov 2018

Cited by 4 | Viewed by 3161

Abstract

One of the most popular micromechanical techniques of determining the local interfacial shear strength (local IFSS, τ_d) between a fiber and a matrix is the single fiber pull-out test. The τ_d values are calculated from the characteristic forces determined from the experimental force–displacement curves using a model which relates their values to local interfacial strength parameters. Traditionally, the local IFSS is estimated from the debond force, F_d, which corresponds to the crack initiation and manifests itself by a “kink” in the force–displacement curve. However, for some specimens the kink point is hardly discernible, and the “alternative” method based on the post-debonding force, F_b, and the maximum force reached in the test, F_max, has been proposed. Since the experimental force–displacement curve includes three characteristic points in which the relationship between the current values of the applied load and the crack length is reliably established, and, at the same time, it is fully determined by only two interfacial parameters, τ_d and the interfacial frictional stress, τ_f, several methods for the determination of τ_d and τ_f can be proposed. In this paper, we analyzed several theoretical and experimental force–displacement curves for different fiber-reinforced materials (thermoset, thermoplastic and concrete) and compared all seven possible methods of τ_d and τ_f calculation. It was shown that the “alternative” method was the most accurate and reliable one, while the traditional approach often yielded the worst results. Therefore, we proposed that the “alternative” method should be preferred for the experimental force–displacement curves analysis. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Graphical abstract

8 pages, 1258 KiB

Open AccessCommunication

Artificial, Triple-Layered, Nanomembranous Wound Patch for Potential Diabetic Foot Ulcer Intervention

by Mostafa Mabrouk, Pradeep Kumar, Yahya E. Choonara, Lisa C. Du Toit and Viness Pillay

Materials 2018, 11(11), 2128; https://doi.org/10.3390/ma11112128 - 29 Oct 2018

Cited by 20 | Viewed by 3180

Abstract

The present work aims to electrospin a triple layered wound patch for potential treatment of diabetic foot ulcers (DFU). The patch consisted of poly(acrylic acid) (PAA) as the skin contacting layer, polyvinyl pyrrolidone (PVP) as the middle layer, and polycaprolactone (PCL) as the outermost layer, wherein the PVP layer was loaded in situ with an antibiotic (ciprofloxacin, CFX). Morphology and mechanical properties were investigated using SEM and texture analysis. Patch quality was studied with regards to wettability, adherence, water resistance, and moisture uptake of individual layers. SEM results confirmed the fibrous and membranous nature of layers with a nano-to-micro size range. Mechanical properties of the composite patch demonstrated a tensile strength of 12.8 ± 0.5 MPa, deformation energy of 54.35 ± 0.1 J/m³, and resilience of 17.8 ± 0.7%, which were superior compared to individual layers. Patch quality tests revealed that the PCL layer showed very low wettability, adherence, and moisture uptake compared to the PVP and PAA layers. In vitro drug release data revealed an increase in cumulative drug release with higher drug loading. The results above confirm the potential of a triple layered, tripolymeric, wound patch for DFU intervention. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Graphical abstract

12 pages, 2650 KiB

Open AccessArticle

Effect of Tow Size and Interface Interaction on Interfacial Shear Strength Determined by Iosipescu (V-Notch) Testing in Epoxy Resin

by Filip Stojceveski, Andreas Hendlmeier, James D. Randall, Chantelle L. Arnold, Melissa K. Stanfield, Daniel J. Eyckens, Richard Alexander and Luke C. Henderson

Materials 2018, 11(9), 1786; https://doi.org/10.3390/ma11091786 - 19 Sep 2018

Cited by 6 | Viewed by 4706

Abstract

Testing methodologies to accurately quantify interfacial shear strength (IFSS) are essential in order to understand fiber-matrix adhesion. While testing methods at a microscale (single filament fragmentation test—SFFT) and macroscale (Short Beam Shear—SBS) are wide spread, each have their own shortcomings. The Iosipescu (V-notch) tow test offers a mesoscale bridge between the microscale and macroscale whilst providing simple, accurate results with minimal time investment. However, the lack of investigations exploring testing variables has limited the application of Iosipescu testing to only a handful of studies. This paper assesses the effect of carbon fiber tow size within the Iosipescu tow test for epoxy resin. Tow sizes of 3, 6, and 9 k are eminently suitable, while more caution must be shown when examining 12, and 15 k tows. In this work, tows at 18 and 24 k demonstrated failure modes not derived from interfacial failure, but poor fiber wetting. A catalogue of common fracture geometries is discussed as a function of performance for the benefit of future researchers. Finally, a comparison of commercial (T300), amine (T300-Amine), and ethyl ester (T300-Ester) surface modified carbon fibers was conducted. The outcomes of this study showed that the Iosipescu tow test is inherently less sensitive in distinguishing between similar IFSS but provides a more ‘real world’ image of the carbon fiber-epoxy interface in a composite material. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Figure 1

14 pages, 6583 KiB

Open AccessArticle

Online Structural-Health Monitoring of Glass Fiber-Reinforced Thermoplastics Using Different Carbon Allotropes in the Interphase

by Michael Thomas Müller, Hendrik Florian Pötzsch, Uwe Gohs and Gert Heinrich

Materials 2018, 11(7), 1075; https://doi.org/10.3390/ma11071075 - 25 Jun 2018

Cited by 7 | Viewed by 3424

Abstract

An electromechanical response behavior is realized by nanostructuring the glass fiber interphase with different highly electrically conductive carbon allotropes like carbon nanotubes (CNT), graphene nanoplatelets (GNP), or conductive carbon black (CB). The operational capability of these multifunctional glass fibers for an online structural-health monitoring is demonstrated in endless glass fiber-reinforced polypropylene. The electromechanical response behavior, during a static or dynamic three-point bending test of various carbon modifications, shows qualitative differences in the signal quality and sensitivity due to the different aspect ratios of the nanoparticles and the associated electrically conductive network densities in the interphase. Depending on the embedding position within the glass fiber-reinforced composite compression, shear and tension loadings of the fibers can be distinguished by different characteristics of the corresponding electrical signal. The occurrence of irreversible signal changes during the dynamic loading can be attributed to filler reorientation processes caused by polymer creeping or by destruction of electrically conductive paths by cracks in the glass fiber interphase. Full article

(This article belongs to the Special Issue Polymer Composites and Interfaces)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Polymer Composites and Interfaces

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (7 papers)

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI