Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2024
Abstract
The purpose of this review is to report on the state-of-the-art on the interaction of moisture with natural materials and fabricated biomimetic functional materials, with an emphasis upon the hygro-responsive behaviour of wood. The primary objective is to examine how water sorption affects dimensional behaviour and how knowledge of this property in natural plant-based (mainly, but not exclusively wood) materials can be used to inform biomimetic design of moisture-responsive materials and devices. The study examines the literature on natural and bio-inspired materials, concentrating upon sorption kinetics, water migration and location of the sorbed water in the materials and their microstructure and mechanical response of the microstructure and how this affects molecular mobility of the sorbate translating to macrostructural changes. Also included within this review, it is an overview of the main experimental techniques which have been used to investigate the interaction of water with these materials at molecular length scales and how modern techniques can resolve the response of these materials at the cell wall level.
Authors
Zoe Angele Adele Cordhomme Nils Maximilian Dittrich Kristina Bringedal Gedde Romain Guillaume Billy Daniel Beat MuellerAbstract
Despite their relevance in building stock modeling, building lifetimes are poorly understood and tend to form the weakest link in forecasting energy use, greenhouse gas (GHG) emissions, waste generation, and resource use. Here, we develop a methodology to trace building lifetimes for cohorts in two central areas built up after fires in the 1840s. Using Geographical Information System (GIS) data of the current building stock and archival material, we determined yearly hazard rates for buildings within the cohort 1841–1845 in the historical center of Trondheim, Norway. We find that hazard rates are very sensitive to events ranging from global to hyperlocal scales and that demolition rates have slowed down significantly since the 1980s when municipal preservation policies came into effect. In contrast, age-based lifetime approaches fail to capture the effects of such events as they only account for the delay between construction and demolition. We discuss the use and limitations of hazard rates to better reflect changes in demolition that are not correlated with building age. Our study underscores that building lifetimes are a property of a wider system rather than an attribute of individual structures. In that sense, hazard rates are a more suitable approach to capture spatiotemporal changes of building stocks and could be further used in scenarios in dynamic models.
Abstract
No abstract has been registered
Abstract
The study investigated the production process and properties of a new wood-based material called Bioblocks. This sustainable composite is made from medium-density-fibreboard (MDF) residues, citric acid and either sorbitol or hexanediol. The process involves mixing in-water diluted chemicals with the MDF residues and curing the mixture in a laboratory oven to esterify the sorbitol and wood components with citric acid. A design of experiment was used to determine the influence and optima of the different process factors, and an optimised trial further investigated the material properties. The density distribution, compression strength, and TS after 24 h immersion in water according to EN 317 of the Bioblocks were tested. The first trial showed that mainly the amount of water added impacts the product’s properties. The optimised material achieved a sufficient density distribution with an average density of about 420 kg/m3, a compression strength of up to 3.5 N/mm2, and a TS of about 2%. Therefore, Bioblocks are a promising natural material to use waste MDF and substitute fossil, unsustainable materials.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
The global packaging sector has grown consistently, and the use of sustainable materials, including recycled and biodegradable products, is expected to rise. This study focuses on the potential of producing barriers for water and water in moist air (water vapor) from proteins to protect cellulosic materials. Owing to the specific requirements of packaging materials, the main subject of this research was their barrier and strength properties. The scope of this work includes selecting components and their physicochemical treatment to produce functionalized coatings on sprayed paper and pure films, as well as film-coated samples (paper laminated with film). The following tests were used to estimate the hydrophobic, hygroscopic, and strength properties: Cobb absorption, contact angle testing, dynamic vapor sorption, and dynamic mechanical analysis. In most cases, the spray-coated paper and film-coated samples absorbed less liquid water than untreated paper. Wheat gluten protein was the most effective water barrier. In all variants, the vapor sorption, desorption, and hysteresis effects (or the lack thereof) showed significant differences compared to those of cellulosic materials. All variants of the spray-coated and film-coated samples in the dynamic mechanical analysis showed an increase in the strength properties of the samples in comparison to the untreated paper. The increased humidity caused a significant loss in the mechanical properties of all variants, exceeding the strength loss of the untreated control samples.
Abstract
The effects of various cellulose treatments on the hydrophobic properties and sorption behavior with respect to liquid water uptake and water vapor sorption were examined within the study. Different hydrophobic agents based on silicon compounds were applied to improve the properties of cellulose-based sheets. The 1H,1H,2H,2H perfluorooctyltriethoxysilane treatment increased hydrophobicity significantly, while N-octyltriethoxysilane and inorganic sodium silicate solution treatments only slightly affected the properties. Silicone-cellulose interaction varied, influencing the fiber saturation and moisture content of the material. The swelling differences between untreated and treated cellulose and, consequently, the uncovering of new active sorption sites during a swelling process and the increase in the content of bound water were confirmed by the T2 relaxation times analysis. The GDW sorption model estimated maximum water content but lacked activation dynamics. The blocking phenomenon of active sorption sites together with silicone improved hydrophobicity had different mechanisms for applied agents. The 1H,1H,2H,2H perfluorooctyltriethoxysilane additionally cross-linked silane structure and restricted cellulose swelling.
Abstract
No abstract has been registered
Abstract
No abstract has been registered