Recently, due to environmental and sustainability issues, the scientific community has been attracted to renewable natural resources, even for the development of materials intended for structural applications. This work deals with the pre‐treatment of a flax fiber fabric by exploring the effects of the exposure time to nitrogen plasma on the ultimate performance of polypropylene matrix composite laminates potentially usable for the realization of internal parts in the naval sector. Flax fabrics were treated with three different exposure times (5, 10, and 15 min) with the aim to improve the adhesion between the hydrophilic fibers and the hydrophobic matrix. At first, transverse and longitudinal wicking tests were carried out on the treated fabrics in order to evaluate the improvement of the absorption constants after the formation of reactive groups on their surface. The results collected so far in terms of fabric water uptake, tensile, and flexural properties as well as morphological aspects (SEM analysis) and damage evolution (ESPI technique), have indicated that the optimal pre‐treatment time of the reinforcing fabrics is equal to 15 min. Compared to the laminate with untreated fabrics, the specimen with flax fibers treated for 15 min displays higher tensile properties with an increase of 6.8% and 22.31% in ultimate strength and modulus, respectively. More in general, the achievements of this research might be useful to extend the current range of applications of flax fibers even in industrial fields still dominated by conventional fibers.

The future evolution of autonomous mobility and road transportation will require substantial improvements in tyre adherence optimization. As new technologies being deployed in tyre manufacturing reduce total vehicle energy consumption, the contribution of tyre friction for safety and performance enhancement continues to increase. For this reason, the tyre’s grip is starting to drive the focus of many tyre developments nowadays. This is because the tread compound attitude to maximize the interaction forces with the ground is the result of a mix of effects, involving polymer viscoelastic characteristics, road roughness profiles and the conditions under which each tyre works during its lifespan. In such a context, mainly concerning the automotive market, the testing, analysis and objectivation of the friction arising at the tread interface is performed by means of specific test benches called friction testers. This paper reviews the state of the art in such devices’ development and use, with a global overview of the measurement methodologies and with a classification based on the working and specimen motion principle. Most tyre friction testers allow one to manage the relative sliding speed and the contact pressure between the specimen and the counter-surface, while just some of them are able to let the user vary the testing temperature. Few devices can really take into account the road real roughness, carrying out outdoor measurements, useful because they involve actual contact phenomena, but very complex to control outside the laboratory environment.

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