
Heli KangasVTT Technical Research Centre of Finland | vtt
Heli Kangas
D.Sc. (Tech.)
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32
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Publications (32)
The main objective of the project FireCellCoat is the development of bio-inspired, fire-retardant wood coatings based on microfibrillated cellulose (MFC) that will protect wood-based building products in interior and exterior applications. The coatings shall fulfil the technical requirements for interior wall paints and exterior wood coatings; in a...
Cellulose is an abundant and sustainable material that is receiving more and more attention in different industries. In the context of additive manufacturing, it would be even more valuable. However, there are some challenges to overcome in processing cellulose-based materials. Therefore, this study used a new thermoplastic cellulose-based granulat...
Enabling high loadings of microfibrillated cellulose for application in wood coatings with improved functionalities: a novel approach using emulsion polymerisation
This article presents a Finnish social design study that focuses on consumer perspectives and future expectations related to bio-based products and brands. The qualitative regional study addresses the global concern associated with sustainability of the bioeconomy. Because a gap in research was identified from the regional consumer perspective, the...
3D printing enables sustainable product innovations through novel design, reduced use of materials, and local manufacturing. Sustainable 3D printing can further be realized using recyclable materials. Cellulose is an abundantly available renewable material. Modified celluloses, such as thermoplastic cellulose esters, are widely used in injection mo...
Phosphorylated cellulosic micro(nano)fibrillated materials are increasingly considered for flame-retardant applications as a biobased alternative to their halogen-based counterparts. Most of the reported cellulose functionalization strategies, however, are realized at low solids contents and/or involve energy-intensive fiber disintegration methods....
The increasing environmental awareness is driving towards novel sustainable high-performance materials applicable for future manufacturing technologies like additive manufacturing (AM). Cellulose is abundantly available renewable and sustainable raw material. This work focused on studying the properties of thermoplastic cellulose-based composites a...
Cellulose is the most abundant polymer in the world, and cellulose nanomaterials thus present a sustainable material of high interest. Cellulose nanomaterials have a wide industrial application potential in several industrial sectors. At present, cellulose nanomaterials are produced globally, the capacities ranging from small industrial to laborato...
Soda-ethanol pulps, prepared from a forestry residue pine sawdust, were treated according to high-consistency enzymatic fibrillation technology to manufacture nanocellulose. The obtained nanocellulose was characterized and used as ink for three-dimensional (3D) printing of various structures. It was also tested for its moisture sorption capacity an...
Cellulose microfibrils (CMF) are a promising biobased material with unique nanospecific properties, giving them potential for use in numerous applications. Based on this, cost-effective and novel high-consistency enzymatic fibrillation (HefCel) technology was used to produce CMF, which was further used to reinforce middle ply of board structure and...
Cellulose fibers obtained by organosolv process were used in preparing PLA/fiber composites. In an attempt to improve the adhesion between the fibers and the polymer matrix, the cellulose fibers were treated chemically using stearoyl chloride as well as enzymatically by laccase. The addition of the cellulose fibers to the PLA matrix had a positive...
This paper considers the EHS aspects of cellulose nanomaterials by reviewing the published literature, considering two case studies on toxicity testing of CNFs and summarizing the progress in legislation in the field. Generally, the published results have revealed no immediate safety threats, but indications of dose-dependent toxicity and inflammat...
Birch wood chips were cooked in acetic acid in the presence of phosphinic acid according to the Lignofibre (LGF) organosolv process. The cooking trials were performed according to an experimental design with process time, temperature, and the presence (or absence) of alkaline pre-extraction as the factors. Delignification was enhanced by increased...
LignoFibre (LGF) organosolv process is a potential novel fractionation method for biomass, yielding cellulose, lignin and hemicelluloses. Depending on the solvent used, the LGF fractions have potential in numerous biomaterial and chemical applications. Unbleached acetic acid LGF cellulose fibres showed promising results as reinforcement fibres in c...
A finely ground fibrillated cellulose was fractionated into separate size fractions. The characteristics of the smallest size fractions were studied, and the toxicity to humans was tested as part of a safety assessment. Morphological studies performed with state-of-the-art methods, such as scanning electron microscopy and atomic force microscopy, s...
The effect of different pre-commercial and commercial fibrillated cellulosic additives on paper strength properties was investigated in this work. The goal was to study the physical properties of paper and board when using the fibrillated cellulosic additives in paper board samples made of bleached softwood kraft pulp (BSKP). The results showed tha...
The most important properties of fibrillated celluloses and the state-of-the-art methods for their characterization are discussed on the basis of literature review and our collective experience on the material. Five mechanically manufactured fibrillated celluloses were analysed with a combination of methods, revealing information on their morpholog...
Fibrillation of chemical and mechanical pulps with different lignin contents was studied. The pulps were ion exchanged into their sodium form prior to fibrillation and fibrillated with an increasing level of energy using high-shear friction grinding. The fibrillated samples were characterized for their chemical composition, morphology, rheological...
Birch chips were cooked by means of the Lignofibre (LGF) organosolv process in acetic acid (AA) and phosphinic acid (H3PO2) at 150°C. The delignification rate and structure of the dissolved lignin was followed as a function of time. The degree of delignification increased steadily up to 88% during the 120 min treatment time. The dissolved lignins w...
For light-weight porous materials, there is an increasing interest in replacing synthetic materials by biomaterials such as wood fibres. In this study, the effects of different wood fibres and the influence of nanofibrillated cellulose on foam formation and solid material properties were elucidated. Different methods such as oven and freeze drying...
The potential of different organosolv processes, based on use of acetic acid as the cooking solvent, to produce high-quality pulps meeting the requirements for dissolving pulps was evaluated. The Lignofibre (LGF) and Formacell processes produced pulps with acceptable delignification degree at short cooking times. Both of these pulps were readily bl...
Development of fiber strength properties and morphological changes on the surface of bleached hardwood kraft pulp after treatment with commercial cellobiohydrolase (CBH) was evaluated. Tensile and tear indices showed no significant effect of the treatment. The treatment resulted in reduction of wet zero-span strength, while the dry zero-span values...
The aim of this work was to obtain knowledge on how peroxide bleaching anddithionite bleaching change the surface chemistry of mechanical pulps, as well as of isolated fibres and fines, by using chemical analysis in combination with two surface-sensitive spectroscopic methods, ESCA (Electron Spectroscopy for Chemical Analysis) and ToF-SIMS (Time-of...
The surface chemistry of thermomechanical pulp (TMP) was modified with specific enzymes and the effect of extensive enzymatic treatments was studied with surface-sensitive spectroscopic methods (ESCA and ToF-SIMS) and by contact angle measurements. Fibers and different types of fines, i.e. fibrils and flakes, were isolated from the enzymatically tr...
Thermomechanical pulps were produced by refining spruce wood (Picea abics) chips at various specific energy consumptions. The surface morphology and chemistry of isolated fibres were studied. Different types affines, i.e. flakes and fibrils, were characterized chemically to obtain information about their origin in the fibre wall. After the two main...
Different types of fines, i.e. fibrils and flakes, were separated from thermomechanical pulp (IMP) fibers and their surface chemical and morphological properties were studied and compared to those of fibers. Fines contained more extractives and lignin than fibers, both on their surface and in the bulk. Fibrillar fines were especially rich in extrac...
The chemical compositions of IMP fines and material isolated from the surface layers of IMP long fibers were compared with that of the inner layers (i.e. bulk) of the long fibers. Both fines and fiber surface layers contained more extractives, lignin and pectins than the bulk fibers. The fiber surface layer material consisted mainly of fibrils, whi...
In this work the effects of transition metals (Co, Cu, Fe, Mn, Ni) in a conventional batch kraft cook were investigated. The influence of each transition metal on delignification and pulp properties was studied separately. Pulps were also cooked from chips pre-treated with acid or chelating agent. Pre-treatment of chips by acid washing or chelation...
The aim of this work was to study the surface chemical and morphological properties of different mechanical pulps with special focus on the effects of refining, bleaching and enzymatic modification on the surface properties of the isolated pulp fractions, namely fibers, fibrillar fines and flake-like fines. Special emphasis was placed on evaluating...