Recently, there has been a rapid growth in research and innovation in the natural fibre composite (NFC) area. Interest is warranted due to the advantages of these materials compared to others, such as synthetic fibre composites, including low environmental impact and low cost and support their potential across a wide range of applications. Much effort has gone into increasing their mechanical performance to extend the capabilities and applications of this group of materials. This review aims to provide an overview of the factors that affect the mechanical performance of NFCs and details achievements made with them.

A review of recent developments in natural fibre composites and their mechanical performance

Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities

Introduction to surface topography.- The areal field parameters.- The areal feature parameters.- Areal filtering methods.- Areal form removal.- Areal fractal methods.- Choosing the appropriate parameter.- Characterization of individual areal features.- Multi-scale signature of surface topography.- Correlation of areal surface texture parameters to solar cell efficiency.- Characterisation of cylinder liner honing textures for production control.- Characterization of the mechanical bond strength for copper on glass plating applications.- Inspection of laser structured cams and conrods.- Road surfaces.

Characterisation of Areal Surface Texture

Optical coherence tomography (OCT), a method for depth-resolved imaging within turbid media based on the concept of low-coherence interferometry, rapidly evolved in the recent years with the development of a multitude of new functionalities and modalities. Biomedical research and diagnostics have been up to now the main driving forces for the reported applications and progress in OCT. The characteristics of OCT, precisely the ability to provide high-resolution images in a contact-free way, render this technique also attractive for a broad spectrum of research topics and applications outside the biomedical field. Consequently, a variety of novel applications for OCT and developments for the method itself have started to emerge. In this review we will give a detailed overview of the so far presented OCT-based methods and applications, ranging from dimensional metrology, material research and non-destructive testing, over art diagnostics, botany, microfluidics to data storage and security applications, and include new data from a study on penetration depths in various polymer materials as well as on birefringence imaging of different crystalline polymer structures. Finally, advanced and related OCT techniques are presented with high potential for future applications outside the biomedical field.

Beyond biomedicine: a review of alternative applications and developments for optical coherence tomography

Silane-functionalized graphene oxides (sGOs) were fabricated with four different self-assembled monolayers (SAMs) to reinforce an epoxy adhesive, with the aim of improving the bonding strength of carbon/epoxy composites. The oxygen-containing groups on the surface of graphene oxide (GO) were converted by the SAMs to amine, epoxy, or alkyl groups. The successful reaction between the silane molecules of the SAMs and functional groups of GO was evidenced by the results of different characterization methods such as Fourier transform infrared spectroscopy. It was found that the average thickness of the sGO flakes was higher than that of GO flakes. The bonding strength of a carbon fiber/epoxy composite, tested with a single lap joint bonded with an epoxy adhesive, was increased by 53% after the addition of a sGO that contained amine groups. These results show that sGOs, especially those containing amine functional groups, can strengthen the interfacial bonding between the carbon fibers and epoxy adhesive.

Using silane-functionalized graphene oxides for enhancing the interfacial bonding strength of carbon/epoxy composites

Glass/epoxy and carbon/epoxy composites were manufactured using a series of polyester and polyamide based peel ply treatments. The influence of peel ply removing upon surface characteristics was assessed with performing contact angle measurements, laser profilometry, SEM and ToF-SIMS analysis. The surface properties of the composite material prior to bonding and the single lap shear performances of resulting assemblies were compared, in order to elucidate the decisive parameters governing adhesion qualities. From a general point of view, the roughness and the chemical nature of the peel ply used strongly influence the properties of the adherent–adhesive system assembly.

Peel ply surface treatment for composite assemblies: Chemistry and morphology effects

Surface treatment of carbon/epoxy and glass/epoxy composites with an excimer laser beam

Roughness and fibre reinforcement effect onto wettability of composite surfaces

Influence of fibre reinforcement and peel ply surface treatment towards adhesion of composite surfaces

This work aims to point out the influence of the polymer surface layer on the adhesion of polymer matrix composites. To this end, correlations between surface parameters (chemistry, roughness, wettability, morphology, etc.) resulting from several surface treatments or preparations and single lap shear tests are performed. The results presented here show the usefulness of surface cleaning and the influence of the manufacturing process before the adhesion stage. Moreover, the use of peel ply surface treatment is also evidenced in terms of surface roughening and cleaning. Furthermore, most of the available surface treatments are limited by the cohesive failure occurring under the polymer surface layer at the fiber—polymer interface of the composite material. Hence, laser ablation is proposed as an alternative way to increase adhesion performance when compared to common surface treatments.

Q. Bénard

Papers

Peel ply surface treatment for composite assemblies: Chemistry and morphology effects

Surface treatment of carbon/epoxy and glass/epoxy composites with an excimer laser beam

Roughness and fibre reinforcement effect onto wettability of composite surfaces

Influence of fibre reinforcement and peel ply surface treatment towards adhesion of composite surfaces

Influence of the Polymer Surface Layer on the Adhesion of Polymer Matrix Composites