Kurzfassung

Materials with adaptive vapor permeability play an essential role in construction, particularly in as semblies that must prevent moisture ingress during winter while allowing drying during summer. Although commercial moisture-dependent vapor retarders exist, they are almost exclusively plastic based multilayer products, which limits their recyclability and hinders material separation after use. Paper, by contrast, is highly recyclable and widely available, yet no paper-based vapor retarder...Materials with adaptive vapor permeability play an essential role in construction, particularly in as semblies that must prevent moisture ingress during winter while allowing drying during summer. Although commercial moisture-dependent vapor retarders exist, they are almost exclusively plastic based multilayer products, which limits their recyclability and hinders material separation after use. Paper, by contrast, is highly recyclable and widely available, yet no paper-based vapor retarder with humidity-adaptive permeability currently exists. This technological gap motivates the development of a paper-based, humidity-adaptive vapor retarder that provides both the required hygrothermal and mechanical performance for building applications. However, developing such a system is challenging because it requires satisfying multiple, sometimes competing, criteria: humidity-dependent vapor diffusion resistance, mechanical durability, dimensional stability, and recyclability. The central goal of Project C04 is to develop a paper-based, moisture-variable vapor retarder whose sd-value can adapt to climatic boundary conditions. Specifically, the project aims to achieve sd-values in the range of approximately 2 m at high relative humidity (summer conditions) and up to 35 m at low relative humidity (winter conditions), thereby matching the functional performance of commercial retarders while offering a fully recyclable, bio-based alternative. Achieving such adaptive behavior requires a fundamental understanding of vapor transport mechanisms in paper sheets and laminates as well as the ability to tailor fiber orientation, pore structure, and physicochemical functionalization.» weiterlesen» einklappen