Search

The widespread use of synthetic composite materials has raised environmental concerns due to their non-biodegradability and energy-intensive production. This paper explores the potential of natural composites, specifically flax–polypropylene, as a sustainable alternative to traditional composites for semi-structural applications. In fact, the mechanical properties of flax–polypropylene composites are similar to synthetic ones (such as those made with E-glass fibers). However, processing challenges related to fiber–matrix interaction and material degradation necessitate suited process parameters for this sustainable type of material. For this reason, this review highlights the importance of optimizing existing manufacturing processes, such as hot press molding, to better accommodate the specific characteristics of polypropylene–flax composites. By refining the parameters and techniques involved in hot press molding, researchers should overcome current limitations and fully capitalize on its potential to produce composite materials of optimal quality. Therefore, a comprehensive literature assessment was conducted to analyze the properties and processing challenges of flax–polypropylene composites. Key process parameters affecting the material's performance are identified and discussed. By optimizing process parameters for flax–polypropylene composites, it is possible to develop a sustainable and high-performance material with a reduced environmental footprint. Further research is needed to scale up production and explore different applications for this sustainable composite material. [ABSTRACT FROM AUTHOR]

We present a comprehensive review of recent techno-economic analyses concerning the recycling of fibre-reinforced thermoset polymers, delving into the strategies employed. Additionally, we offer insights into the critical issues that necessitate consideration when evaluating solutions for valorizing these materials. Our emphasis lies in advocating for a demand-driven, entrepreneurial approach focused on identifying viable industrial applications for recycled materials, forming the foundation for sustainable techno-economic solutions and viable circular business models. We underscore the imperative for initial public intervention to regulate the recycling process, alter stakeholders' incentives and effectively coordinate actions across involved value chains. [ABSTRACT FROM AUTHOR]

In this work, the influence of hydrothermal ageing on performances of CFRP single lap bonded joints subjected to two types of pre-treatments was investigated. The first is a degreasing pre-treatment, while the second if a laser texturing pre-treatment through a CO2 laser system. The study considered the influence of an aggressive environment on geometrical deviations and mechanical performances of the bonded joints. Measurements showed that adherends were more susceptible to water uptake after ageing, allowing an increase in laminate thickness of about 2.5%. Lap shear tests were carried out and a decrease in obtained mechanical performances was observed only for the degreased specimens, confirming the effectiveness of the adopted laser texturing to reduce ageing effects. Moreover, the proposed laser texturing pre-treatment for bonding is a sustainable process too because reduces the volume of the removed material efficiently with reduced costs. [ABSTRACT FROM AUTHOR]

Diamond tools suitable for machining operations of natural stones can be divided into two groups: cutting tools, including blades, the circular blades and the wires, and the surface machining ones, involving mills and grinders, that can be of different shapes. For the stone sawing process, the most adopted tool type is the diamond mill, whose duration and performance are influenced by various elements such as: the mineralogical characteristics of the material to be machined; the working conditions such as the depth of cut, the feed rate and the spindle speed; the production process of the diamond segment and the characteristics of both the matrix and the diamond, such as the size, the type and the concentration of the diamonds and the metal bond formulation hardness. This work allows to indirectly assess the wear of sintered diamond tools by signal analysis (in time and frequency domain) of the cutting force components acquired in the process. The results obtained represent a fundamental step for the development of a sensory supervision system capable of assessing the tool wear and hence to modify the process parameters in process, in order to optimize cutting performance and tool life. [ABSTRACT FROM AUTHOR]

Surface roughness of the adherends represents an important factor for manufacturing a reliable bonded joint in structural applications. In case of bonding of parts in carbon fibre reinforced polymer (CFRP), an increase of roughness parameters can be obtained with various techniques. In this paper, the morphology obtained from a CO2 laser texturing on CFRP laminates were investigated. CFRP laminates were manufactured and subjected to laser texturing with various densities. In particular, the densities of treatment have been defined as a function of the grid dimensions of the texture. Subsequently, non-contact measurements were carried out to evaluate the evolution of the surface roughness parameters as a function of the density of the laser treatment. Results showed a strong correlation between surface roughness and density of treatment. In conclusion, these results were compared with experimental tests, which showed that the mechanical performance for ENF bonded joints was limited only by the flexural mechanical resistance of the CFRP adherends. As a result of this work, the developed laser texturing approach is potentially able to increase the mechanical resistance in the function of the real local load acting on the complex bonded joint, optimizing time and cost process. [ABSTRACT FROM AUTHOR]