Biocompositi rinforzati con fibre e le loro applicazioni nella progettazione per la sicurezza e la sostenibilità ambientale

Composite materials have taken on a central role in numerous industrial sectors thanks to their high performance-to-weight ratio. Initially used in niche areas such as aerospace, they have gradually spread to the automotive industry, where the evolution of production technologies and environmental regulations have favoured the adoption of lightweight solutions to reduce fuel consumption and emissions. Their versatility derives from the possibility of combining different matrices and reinforcements, modulating their proportions and production processes to obtain superior properties compared to the individual constituents. However, the heterogeneous nature of composites makes end-of-life management complex, as the separation of components is often costly and technically critical. In the context of the transition to circular economy models, there has been growing interest in biocomposites, developed from renewable resources and partially or totally biobased. These materials meet the need to combine high performance and reduced environmental impact, making them one of the most promising areas of contemporary research for replacing current synthetic fibre-reinforced composites. In line with this perspective, this doctoral thesis aims to explore the use of natural composite materials, with a particular focus on fibre-reinforced biocomposites, and to investigate their potential applications in the field of Design for Safety. The initial phase of the research focused on constructing a theoretical-analytical framework for fibre-reinforced biocomposites, analysing their properties, production processes and potential applications in product design. Key concepts were defined, the constituent principles were explored in depth (with particular attention to flax fibre and thermosetting and thermoplastic biobased matrices), and mechanical, physical and aesthetic-perceptual performance was evaluated in comparison with conventional composites. Analysis of the international literature has made it possible to outline the state of the art, highlighting prospects for development and critical issues still open (durability, dimensional stability, moisture resistance, market acceptance). At the same time, a systematic collection of case studies has made it possible to classify applications and products according to materials, processes and sensory characteristics, with the aim of understanding design constraints and logic and identifying an area consistent with DfS. The subsequent focus on the topic of safety, understood as a multidisciplinary field, led to a comparative analysis of regulations, risk contexts and composite material devices. Through parameters of visibility, perceptual intensity and tactile relevance, it was possible to identify the sectors in which the material also contributes to the perception of safety and quality. The survey revealed that, while composite materials are valued primarily for their mechanical properties in industrial and infrastructure applications, in the sports sector, particularly in personal equipment, they take on a communicative and identity-building role, contributing to the construction of the product’s image and the perception of performance, reliability and innovation. The sports sector has therefore emerged as the most suitable context for experimenting with the application of fibre- reinforced biocomposite materials, as the perceptual and sensory dimensions of the material become an integral part of the user experience and emotional relationship with the user. Furthermore, this sector stands out for its greater openness to innovative and sustainable materials, where product costs are less binding than the symbolic, aesthetic and functional values linked to the concept of safety, exclusivity and constructive quality. Based on the evidence that emerged, the research focused on identifying micro-scenarios within the sports sector in order to select a practice that was representative and consistent with the objectives of the PhD programme. The choice was guided by the need to identify an area in which the end user showed both a marked sensitivity to environmental issues and a high level of sensory involvement with the product and the materials it is made of. At this stage, methodologies dedicated to the analysis of the visual-tactile properties of biocomposites were applied, with the aim of constructing evaluation tools capable of integrating perceptual, aesthetic and performance dimensions. This approach made it possible to consider the material not only as a functional component, but also as a communicative element capable of conveying values of naturalness, innovation and sustainability, which are increasingly decisive in the choices of contemporary consumers. A significant contribution was made by the research period at the Canterbury University School of Product Design (New Zealand), which allowed for in-depth study of sensory testing techniques applied to natural fibre composites and consolidated skills in statistical data processing. Discussions with researchers active in the field of sustainable materials also fostered an integrated view of the relationship between material, perception and function, contributing to the validation of the methodological tools adopted. Following the analyses conducted, the micro-scenario identified as most representative was that of mountain biking (MTB), with particular reference to personal protective equipment. This area combines safety, lightness and comfort requirements with a marked identity and expressive dimension of the materials. This choice oriented the research towards an interdisciplinary approach, including the study of the biomechanical dynamics of falls, the classification of impact types and body areas at risk, as well as the analysis of cyclists’ usage habits and aesthetic preferences. Through desk and field surveys conducted at specialised retail outlets, sports centres and communities of practitioners, qualitative and quantitative data were collected on behaviour, functional expectations and perceptions of the materials used in current protective gear. The results were processed to define a structured cognitive framework of the MTB scenario, correlating technical performance and perceptual dimensions with the real needs of users. This process led to the definition of a protective device concept based on natural fibre-reinforced biocomposites, capable of integrating high mechanical performance, ergonomic comfort and a clear aesthetic-material identity. The research process has therefore led to the definition of an experimental method of integration between material design, sensory perception and functional safety, in which biocomposites are no longer considered a simple “green” replacement for synthetic materials, but become a mediator between function and meaning, capable of generating perceptual and cultural value in the design product. From a methodological point of view, the research highlighted the need to redefine the relationship between material, function and perception in the use of biocomposites, considering the material as an active element in the design process. The integration of perceptual and sensory analysis tools with the evaluation of technical performance has made it possible to structure a replicable research model, useful for guiding future applications in the field of sustainable material design. The methodology developed, based on the interaction between experimentation, observation of use and perceptual validation, proposes a systemic approach that overcomes the traditional dichotomy between technical performance and aesthetic value, recognising the material as a communicative vector capable of conveying symbolic, ethical and environmental content. In this sense, the case study developed in the mountain bike sector takes on a paradigmatic value: it demonstrates how fibre-reinforced biocomposites, if properly designed and communicated, can become a driver of design and cultural innovation, contributing to the spread of a new sensitivity towards natural materials and the promotion of responsible, conscious and sustainability-oriented design. The methodology outlined is therefore transferable and adaptable to other design sectors, particularly those in which the perception of materials and the tactile component plays a central role (from automotive to technical furniture to professional protective equipment), confirming the potential of biocomposites as a contemporary design language capable of combining technology, sustainability and aesthetic identity.