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Specific heat capacity of wood is an important material property for fundamental research and timber technology. However, the existing database for heat capacity values is limited, especially for data below 0 °C. Therefore, the aim of this study was to investigate the specific heat capacity of wood with different moisture contents (dry, below and above fibre saturation) in lower temperature. Beech (Fagus sylvatica) and scots pine (Pinus sylvestris) were investigated via differential scanning calorimetry (DSC), equipped with a liquid nitrogen-cooling device, using the sapphire standard. Specific heat capacity for beech and pine were linear within the investigated temperature region. Values above 0 °C are in agreement with existing literature. Both species showed similar results. Based on the obtained results the specific heat capacity for bound water was calculated. The presented results are an important step for increasing the database of wood heat capacity. These findings enable future research for calculating heat-flux, diffusion and moisture transfer in wood.
Martin Nopens; Uta Sazama; Andreas Krause; Michael Fröba. Specific heat capacity of wood between −140 and 50 °C in dry and wet state. Holzforschung 2020, 1 .
AMA StyleMartin Nopens, Uta Sazama, Andreas Krause, Michael Fröba. Specific heat capacity of wood between −140 and 50 °C in dry and wet state. Holzforschung. 2020; ():1.
Chicago/Turabian StyleMartin Nopens; Uta Sazama; Andreas Krause; Michael Fröba. 2020. "Specific heat capacity of wood between −140 and 50 °C in dry and wet state." Holzforschung , no. : 1.
Wood porosity is of great interest for basic research and applications. One aspect is the cell wall porosity at total dry state. When water is absorbed by wood, the uptake of water within the cell wall leads to a dimension change of the material. A hypothesis for possible structures that hold the water is induced cell wall porosity. Nitrogen and krypton physisorption as well as high pressure hydrogen sorption and thermoporosimetry were applied to softwood and hardwood (pine and beech) in dry and wet state for determining surface area and porosity. Physisorption is not able to detect pores or surface area within the cell wall. Krypton physisorption shows surface area up 5 times lower than nitrogen with higher accuracy. With high pressure sorption no inaccessible pore volumes were seen at higher pressures. Thermoporosimetry was not able to detect mesopores within the hygroscopic water sorption region. Physisorption has to be handled carefully regarding the differences between adsorptives. The absence of water-induced mesopores within the hygroscopic region raise doubts on existing water sorption theories that assume these pore dimensions. When using the term “cell wall porosity”, it is important to distinguish between pores on the cell wall surface and pores that exist because of biological structure, as there are no water-induced mesopores present. The finding offers the possibility to renew wood-water-sorption theories because based on the presented results transport of water in the cell wall must be realized by structures lower than two 2 nm. Nanoporous structures in wood at wet state should be investigated more intensively in future.
Martin Nopens; Uta Sazama; Sandra König; Sergej Kaschuro; Andreas Krause; Michael Fröba. Determination of mesopores in the wood cell wall at dry and wet state. Scientific Reports 2020, 10, 1 -11.
AMA StyleMartin Nopens, Uta Sazama, Sandra König, Sergej Kaschuro, Andreas Krause, Michael Fröba. Determination of mesopores in the wood cell wall at dry and wet state. Scientific Reports. 2020; 10 (1):1-11.
Chicago/Turabian StyleMartin Nopens; Uta Sazama; Sandra König; Sergej Kaschuro; Andreas Krause; Michael Fröba. 2020. "Determination of mesopores in the wood cell wall at dry and wet state." Scientific Reports 10, no. 1: 1-11.
The structural integrity of wood–polymer composites (WPC) has not been fully investigated, which can be attributed to a lack of applicable test procedures. In this study, wood–polypropylene composites were assessed by High-Energy Multiple Impact (HEMI) testing. The acquired composites were based on wood particles from various sources and different wood fibre contents, respectively. With respect to wood fibre content, a clear relationship between resistance to impact milling (RIM) and unnotched impact bending strength (acU) was obtained. The lower the fibre content of the WPC the more structural integrity was retained. In return, various wood sources had no effect on acU, but a major impact on RIM values. RIM is suggested to be predominantly affected by structural features, such as fibre/particle content and characteristics, particle agglomerations, and spatial void distribution.
Kim C. Krause; Andreas Krause; Sarah E. Pilz; Christian Brischke. High-energy multiple impact (HEMI) tests of wood–polypropylene composites: new insights in structural integrity. Wood Material Science & Engineering 2020, 1 -4.
AMA StyleKim C. Krause, Andreas Krause, Sarah E. Pilz, Christian Brischke. High-energy multiple impact (HEMI) tests of wood–polypropylene composites: new insights in structural integrity. Wood Material Science & Engineering. 2020; ():1-4.
Chicago/Turabian StyleKim C. Krause; Andreas Krause; Sarah E. Pilz; Christian Brischke. 2020. "High-energy multiple impact (HEMI) tests of wood–polypropylene composites: new insights in structural integrity." Wood Material Science & Engineering , no. : 1-4.
The main objective of this study was to find out if there is any significant correlation between physical properties and interfacial bonding of interphases in wood–plastic composites. To this end, high-density polyethylene (HDPE), mixture of 3% maleic anhydride grafted polyethylene (MAPE) and HDPE (coded as MHDPE) and polylactic acid (PLA) were separately interacted with veneers to identify factors underlying interfaces. Plastics were first melted at 180 °C and dispensed on wood surfaces so that the contact angle (CA) could be directly measured. Wood sanding moderately decreased the CAs of plastics in order of PLA, MHDPE, and HDPE. The treatment of veneers with MAPE comprehensively improved wetting, as the CA of HDPE was significantly reduced on the wood surface after the treatment. Thereafter, the interfacial shear strengths (IFSS) of the wood–polymer interface were determined using the automated bonding evaluation system. PLA had the highest IFSS both for unsanded and sanded veneers. Comparing both parts of this research finally revealed that applying sanding or/and MAPE treatments resulted in lower surface free energy and higher IFSS at the wood–polymer interface. However, our observations support the idea that, at higher temperatures, wetting of composites is mainly influenced by polymer properties rather than interfacial tension at the wood–polymer interface.
Pouria Rezaee Niaraki; Andreas Krause. Correlation between physical bonding and mechanical properties of wood–plastic composites: part 2: effect of thermodynamic factors on interfacial bonding at wood–polymer interface. Journal of Adhesion Science and Technology 2019, 34, 756 -768.
AMA StylePouria Rezaee Niaraki, Andreas Krause. Correlation between physical bonding and mechanical properties of wood–plastic composites: part 2: effect of thermodynamic factors on interfacial bonding at wood–polymer interface. Journal of Adhesion Science and Technology. 2019; 34 (7):756-768.
Chicago/Turabian StylePouria Rezaee Niaraki; Andreas Krause. 2019. "Correlation between physical bonding and mechanical properties of wood–plastic composites: part 2: effect of thermodynamic factors on interfacial bonding at wood–polymer interface." Journal of Adhesion Science and Technology 34, no. 7: 756-768.
This study investigated the mode of action between wood and thermoplastic interphases. For this purpose, the effect of sanding and chemical treatments on the wood surface wettability has been simultaneously evaluated. Contact angle measurements were tested on wood veneers (spruce) using Van Oss-Chaudhury-Good (VOCG) method to determine the surface free energies (SFE). To better understand the mechanism of treatments on the physical interactions, veneers were either/both sanded or/and treated by maleic anhydride grafted with polyethylene (MAPE) so that the analysis of surface pre-coating and its influence on the polarity and the dispersive properties of the wood-polymer interface can be further studied. The results showed a significant increment of both surface roughness and interfacial area after sanding which improved pre-coating of plastic on the wood surface consequently. Analysis of wetting parameter showed compatibility between two types of surface modification, as the treatment of veneers by sanding and MAPE together resulted in higher contact angles and lower surface free energy (SFE) on the wood surfaces. MAPE could entirely cover the wood veneers and form a non-polar surface, which suggests the effectiveness of this chemical and its compatibility with the sanding operation on the wood surface.
Pouria Rezaee Niaraki; Andreas Krause. Correlation between physical bonding and mechanical properties of wood plastic composites: Part 1: interaction of chemical and mechanical treatments on physical properties. Journal of Adhesion Science and Technology 2019, 34, 744 -755.
AMA StylePouria Rezaee Niaraki, Andreas Krause. Correlation between physical bonding and mechanical properties of wood plastic composites: Part 1: interaction of chemical and mechanical treatments on physical properties. Journal of Adhesion Science and Technology. 2019; 34 (7):744-755.
Chicago/Turabian StylePouria Rezaee Niaraki; Andreas Krause. 2019. "Correlation between physical bonding and mechanical properties of wood plastic composites: Part 1: interaction of chemical and mechanical treatments on physical properties." Journal of Adhesion Science and Technology 34, no. 7: 744-755.
In this study, we investigated injection molded wood-polypropylene composites based on various wood sources and their decay resistance against white rot (Trametes versicolor) and brown rot (Coniophora puteana) in a laboratory test according to EN 15534-1:2014. The manufactured composites consisted of poplar (Populus spp.), willow (Salix spp.), European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) H. Karst.), and a commercial wood source (Arbocel® C100), respectively. All formulations were compounded on a co-rotating twin screw extruder and subsequently injection molded to wood–PP specimens with a wood content of 60% or 70% by weight. It was found that the test procedure had a significant effect on the mechanical properties. Loss in mechanical properties was primarily caused by moisture and less by fungal decay. Moisture caused a loss in the modulus of rupture and modulus of elasticity of 34 to 45% and 29 to 73%, respectively. Mean mass and wood mass losses were up to a maximum of 3.7% and 5.3%, respectively. The high resistance against fungal decay was generally attributed to the encapsulation of wood by the polymer matrix caused by sample preparation, and enhanced by reduced moisture uptake during the preconditioning procedure. Notable differences with respect to the wood particle source and decay fungi were also observed. Structural characterization confirmed the decay pattern of the fungi such as void cavities close the surface and the deposition of calcium oxalates.
Kim Christian Krause; Christian Brischke; Tim Koddenberg; Andreas Buschalsky; Holger Militz; Andreas Krause. Resistance of Injection Molded Wood-Polypropylene Composites against Basidiomycetes According to EN 15534-1: New Insights on the Test Procedure, Structural Alterations, and Impact of Wood Source. Fibers 2019, 7, 92 .
AMA StyleKim Christian Krause, Christian Brischke, Tim Koddenberg, Andreas Buschalsky, Holger Militz, Andreas Krause. Resistance of Injection Molded Wood-Polypropylene Composites against Basidiomycetes According to EN 15534-1: New Insights on the Test Procedure, Structural Alterations, and Impact of Wood Source. Fibers. 2019; 7 (10):92.
Chicago/Turabian StyleKim Christian Krause; Christian Brischke; Tim Koddenberg; Andreas Buschalsky; Holger Militz; Andreas Krause. 2019. "Resistance of Injection Molded Wood-Polypropylene Composites against Basidiomycetes According to EN 15534-1: New Insights on the Test Procedure, Structural Alterations, and Impact of Wood Source." Fibers 7, no. 10: 92.
Research Highlights: When investigating the sorption of water on lignocellulosic materials, the sorption or mixing enthalpy is an interesting parameter that, together with the sorption isotherms commonly measured, can be used to characterize and understand the sorption process. We have compared different methods to assess these enthalpies. Additionally, we propose a sorption nomenclature. Background and Objectives: Sorption enthalpies are non-trivial to measure. We have, for the first time, measured sorption enthalpies on the same materials with four different methods, to be able to compare the method’s strengths and weaknesses. Materials and Methods: The following four methods were used on beech and Scots pine wood: isosteric heat, solution calorimetry, sorption calorimetry, and RH perfusion calorimetry. Results: The results for beech and pine were similar, and were in general agreement with the literature. We do not recommend one of the methods over the others, as they are quite different, and they can therefore be used to elucidate different aspects of the interactions between water and, for example, novel biobased materials (modified woods, cellulose derivatives, and regenerated cellulose).
Martin Nopens; Lars Wadsö; Christian Ortmann; Michael Fröba; Andreas Krause. Measuring the Heat of Interaction between Lignocellulosic Materials and Water. Forests 2019, 10, 674 .
AMA StyleMartin Nopens, Lars Wadsö, Christian Ortmann, Michael Fröba, Andreas Krause. Measuring the Heat of Interaction between Lignocellulosic Materials and Water. Forests. 2019; 10 (8):674.
Chicago/Turabian StyleMartin Nopens; Lars Wadsö; Christian Ortmann; Michael Fröba; Andreas Krause. 2019. "Measuring the Heat of Interaction between Lignocellulosic Materials and Water." Forests 10, no. 8: 674.
WPC boards were produced from recycled low-density polyethylene (rLDPE) and wood from three different invasive species found in the Western Cape, South Africa with the aim of using them as ceiling boards in low-cost housing projects. The study determined differences between two different types of rLDPE and the tree species, as well as tree composition with regards to physical and mechanical board properties. It was found that the difference between using only wood, or the entire tree – with bark, twigs and leaves – as filler in WPC boards is hardly significant. However, the difference between the two sourced recycled plastic was notable.
James B. Acheampong; Marco de Angelis; Andreas Krause; Martina Meincken. The effect of raw material selection on physical and mechanical properties of wood plastic composites made from recycled LDPE and wood from invasive trees in South Africa. Wood Material Science & Engineering 2019, 16, 118 -123.
AMA StyleJames B. Acheampong, Marco de Angelis, Andreas Krause, Martina Meincken. The effect of raw material selection on physical and mechanical properties of wood plastic composites made from recycled LDPE and wood from invasive trees in South Africa. Wood Material Science & Engineering. 2019; 16 (2):118-123.
Chicago/Turabian StyleJames B. Acheampong; Marco de Angelis; Andreas Krause; Martina Meincken. 2019. "The effect of raw material selection on physical and mechanical properties of wood plastic composites made from recycled LDPE and wood from invasive trees in South Africa." Wood Material Science & Engineering 16, no. 2: 118-123.
Fluorescence microscopy was applied to understand adhesion interfaces developed within laminated composite sandwiches formed between poly(lactic acid) (PLA) and wood veneers. Composites formed with maple veneer had greater tensile bond strength when manufactured at 200 °C (10.4 N/mm2) compared to formation at 140 °C (8.7 N/mm2), while significantly lower bond strength was achieved using spruce veneers, at 5.2 and 3.5 N/mm2, respectively. Qualitative and quantitative confocal microscopy assessments revealed differing bondline thicknesses and PLA ingress within the wood ultrastructure. Forming maple veneer composites at 200 °C promoted greater PLA mobility away from the bondline to reinforce the wood–PLA interface and deliver associated greater composite bond strength. The addition of 25% wood fibre to PLA led to fibre alignment and overlap within bondlines contributing to relatively thicker, heterogeneous bondlines. Study outcomes show that the composite processing temperature impacts the adhesion interface and composite performance and will have broad application over veneer overlays, laminates and wood plastic composites (WPCs) using wood, particles or fibres with PLA.
Warren Grigsby; Victor Gager; Kimberly Recabar; Andreas Krause; Marc Gaugler; Jan Luedtke. Quantitative Assessment and Visualisation of the Wood and Poly(Lactic Acid) Interface in Sandwich Laminate Composites. Fibers 2019, 7, 15 .
AMA StyleWarren Grigsby, Victor Gager, Kimberly Recabar, Andreas Krause, Marc Gaugler, Jan Luedtke. Quantitative Assessment and Visualisation of the Wood and Poly(Lactic Acid) Interface in Sandwich Laminate Composites. Fibers. 2019; 7 (2):15.
Chicago/Turabian StyleWarren Grigsby; Victor Gager; Kimberly Recabar; Andreas Krause; Marc Gaugler; Jan Luedtke. 2019. "Quantitative Assessment and Visualisation of the Wood and Poly(Lactic Acid) Interface in Sandwich Laminate Composites." Fibers 7, no. 2: 15.
In this study, various wood material sources were used for the manufacture of wood-polymer composites (WPC). The materials were categorised as virgin wood particles (VWP), reprocessed WPC particles (RWP) and recycled thermoset composite particles (RCP) and derived from two virgin wood sources, three-layer particleboards, medium-density fibreboards (MDF) boards, or two different wood/polypropylene composites. All produced wood-polypropylene compounds contained 60% wood material and were manufactured using a co-rotating extruder. Malleated polypropylene was used as a coupling agent. Specimens were injection moulded and subsequently tested for their physico-mechanical properties. To characterize particles before and after processing, dynamic image analysis (DIA) measurement were performed. Additionally, X-ray micro-computed tomography (XµCT) was used to characterize the internal structure of the composites and to verify the obtained particle’s characteristics. It was found that length and aspect ratio of particles were remarkably different before and after processing (loss in length of 15–70% and aspect ratio of 10–40%). Moreover, there were notably differences between the particle sources (RCP retained the highest length and aspect ratio values, followed by VWP and RWP). The results suggest that increased aspect ratios can indeed significantly improve mechanical properties (up to 300% increase in impact bending strength and 75% increase in tensile strength, comparing WPC based either on virgin spruce or MDF material). This phenomenon is suggested to be partially superimposed by improved dispersion of particles, which is expected due to lower variance and increased mechanical properties of RWP composites. However, no notable alterations were observed for composite density. Reprocessed WPC and, particularly, RCP material have proved to be an appealing raw material substitute for the manufacturing of wood–polymer composites.
Kim Christian Krause; Philipp Sauerbier; Tim Koddenberg; Andreas Krause. Utilization of Recycled Material Sources for Wood-Polypropylene Composites: Effect on Internal Composite Structure, Particle Characteristics and Physico-Mechanical Properties. Fibers 2018, 6, 86 .
AMA StyleKim Christian Krause, Philipp Sauerbier, Tim Koddenberg, Andreas Krause. Utilization of Recycled Material Sources for Wood-Polypropylene Composites: Effect on Internal Composite Structure, Particle Characteristics and Physico-Mechanical Properties. Fibers. 2018; 6 (4):86.
Chicago/Turabian StyleKim Christian Krause; Philipp Sauerbier; Tim Koddenberg; Andreas Krause. 2018. "Utilization of Recycled Material Sources for Wood-Polypropylene Composites: Effect on Internal Composite Structure, Particle Characteristics and Physico-Mechanical Properties." Fibers 6, no. 4: 86.
Dark lock-in thermography (DLIT) combined with the ’local I-V’ method is applied to derive spatial-resolved efficiency losses and potentials for cast-mono PERC solar cells during wafer and cell developing phase. For the DLIT image evaluation method, four DLIT images at -1 V, 0.510 V, 0.555 V and 0.615 V as well as a lumped series resistance image from photoluminescence are measured at a cast-mono PERC solar cell exemplarily. From these five images, the ‘local I-V’ method derives locally I-V curves which allow spatial-resolved efficiency, open-circuit voltage and fill factor images. Main losses visible in the efficiency image could be separated into: small angle grain boundaries of the cast-mono wafer, stripe like contamination due to belt transportation within a wet bench, increased contact resistance at rear contacts at two sides of the cell and highly recombination active rear pad areas. The overall efficiency drop due to these local losses is calculated to about 0.8%abs.
Matthias Müller; Matthias Wagner; Andreas Krause; Dirk Holger Neuhaus. Quantitative local efficiency loss analysis on cast-mono PERC solar cells using the DLIT ‘local I-V’ method. AIP Conference Proceedings 2018, 1999, 020020 .
AMA StyleMatthias Müller, Matthias Wagner, Andreas Krause, Dirk Holger Neuhaus. Quantitative local efficiency loss analysis on cast-mono PERC solar cells using the DLIT ‘local I-V’ method. AIP Conference Proceedings. 2018; 1999 (1):020020.
Chicago/Turabian StyleMatthias Müller; Matthias Wagner; Andreas Krause; Dirk Holger Neuhaus. 2018. "Quantitative local efficiency loss analysis on cast-mono PERC solar cells using the DLIT ‘local I-V’ method." AIP Conference Proceedings 1999, no. 1: 020020.
Thermomechanical wood fibers, as usually used for medium density fiberboard or cardboard production, feature promising characteristics, like a high aspect ratio, for the utilization in thermoplastic composites. The present study investigates the influence of fiber loading and fiber geometry on the mechanical properties of wood-polypropylene composites in order to confirm the results that were found in a previously published literature review. Composites were compounded at fiber contents from 20 to 60 wt.%, using a co-rotating twin-screw extruder and subsequently injection molded to test specimens. Field emission scanning electron microscopy was carried out to evaluate the fracture morphology of the composites. Fiber length was evaluated using an applying a dynamic image analysis system. Compounding reduced fiber lengths up to 97%. The mechanical properties decreased with increasing fiber content for composites without a coupling agent. Strength properties peaking at a fiber content of 50 wt.% for composites containing MAPP. Tensile strength and flexural strength reached 48.1 and 76.4 MPa, respectively. However, it was found that the processing of these fibers into conventional compounding equipment is still challenging.
Oliver Mertens; Kim C. Krause; Matthias Weber; Andreas Krause. Performance of thermomechanical wood fibers in polypropylene composites. Wood Material Science & Engineering 2018, 15, 114 -122.
AMA StyleOliver Mertens, Kim C. Krause, Matthias Weber, Andreas Krause. Performance of thermomechanical wood fibers in polypropylene composites. Wood Material Science & Engineering. 2018; 15 (2):114-122.
Chicago/Turabian StyleOliver Mertens; Kim C. Krause; Matthias Weber; Andreas Krause. 2018. "Performance of thermomechanical wood fibers in polypropylene composites." Wood Material Science & Engineering 15, no. 2: 114-122.
The influence of plasma treatment performed at atmospheric pressure and ambient air as process gas by a dielectric barrier discharge (DBD) on the morphological and chemical surface characteristics of wood-polymer composites (WPC) was investigated by applying several surface-sensitive analytical methods. The surface free energy showed a distinct increase after plasma treatment for all tested materials. The analyzing methods for surface topography —laser scanning microscopy (LSM) and atomic force microscopy (AFM) — revealed a roughening induced by the treatment which is likely due to a degradation of the polymeric surface. This was accompanied by the formation of low-molecular-weight oxidized materials (LMWOMs), appearing as small globular structures. With increasing discharge time, the nodules increase in size and the material degradation proceeds. The surface degradation seems to be more serious for injection-molded samples, whereas the formation of nodules became more apparent and were evenly distributed on extruded surfaces. These phenomena could also be confirmed by scanning electron microscopy (SEM). In addition, differences between extruded and injection-molded surfaces could be observed. Besides the morphological changes, the chemical composition of the substrateś surfaces was affected by the plasma discharge. Infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) indicated the formation of new oxygen containing polar groups on the modified surfaces.
Benedikt Hünnekens; Georg Avramidis; Gisela Ohms; Andreas Krause; Wolfgang Viöl; Holger Militz. Impact of plasma treatment under atmospheric pressure on surface chemistry and surface morphology of extruded and injection-molded wood-polymer composites (WPC). Applied Surface Science 2018, 441, 564 -574.
AMA StyleBenedikt Hünnekens, Georg Avramidis, Gisela Ohms, Andreas Krause, Wolfgang Viöl, Holger Militz. Impact of plasma treatment under atmospheric pressure on surface chemistry and surface morphology of extruded and injection-molded wood-polymer composites (WPC). Applied Surface Science. 2018; 441 ():564-574.
Chicago/Turabian StyleBenedikt Hünnekens; Georg Avramidis; Gisela Ohms; Andreas Krause; Wolfgang Viöl; Holger Militz. 2018. "Impact of plasma treatment under atmospheric pressure on surface chemistry and surface morphology of extruded and injection-molded wood-polymer composites (WPC)." Applied Surface Science 441, no. : 564-574.
F. Yağmur Bütün; Aaron K. Mayer; Kolja Ostendorf; Ole-Elias Z. Gröne; Kim C. Krause; Christian Schöpper; Oliver Mertens; Andreas Krause; Carsten Mai. Recovering fibres from fibreboards for wood polymer composites production. International Wood Products Journal 2018, 9, 42 -49.
AMA StyleF. Yağmur Bütün, Aaron K. Mayer, Kolja Ostendorf, Ole-Elias Z. Gröne, Kim C. Krause, Christian Schöpper, Oliver Mertens, Andreas Krause, Carsten Mai. Recovering fibres from fibreboards for wood polymer composites production. International Wood Products Journal. 2018; 9 (2):42-49.
Chicago/Turabian StyleF. Yağmur Bütün; Aaron K. Mayer; Kolja Ostendorf; Ole-Elias Z. Gröne; Kim C. Krause; Christian Schöpper; Oliver Mertens; Andreas Krause; Carsten Mai. 2018. "Recovering fibres from fibreboards for wood polymer composites production." International Wood Products Journal 9, no. 2: 42-49.
The distinctive length and morphology characteristics of thermomechanical produced wood fibers make it a promising candidate for the utilization in polymer composites. However, due to the low bulk density of these fibers, the feeding into the compounding process (i.e., extruders) is quite challenging. In this study, a novel simultaneous defibration and compounding process are conducted in order to solve the feed-in problem of thermomechanical fibers. A disc-refiner was used to defibrate wood chips to fibers and compound the fibers with neat polymer granulates in one process step. After the process, the material showed typically thermomechanical fibers with chopped polymer particles which were inseparably attached to the fiber. The observed mechanical properties of the composites were slightly lower than some literature values. With field emission scanning electron microscopy and X-ray microtomography analysis, voids and a polymer enriched surface were found influencing the composites performance. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45859.
Oliver Mertens; Kim Christian Krause; Andreas Krause. Evaluation of wood fiber composites based on a novel simultaneous defibration and compounding process. Journal of Polymer Science 2017, 135, 1 .
AMA StyleOliver Mertens, Kim Christian Krause, Andreas Krause. Evaluation of wood fiber composites based on a novel simultaneous defibration and compounding process. Journal of Polymer Science. 2017; 135 (7):1.
Chicago/Turabian StyleOliver Mertens; Kim Christian Krause; Andreas Krause. 2017. "Evaluation of wood fiber composites based on a novel simultaneous defibration and compounding process." Journal of Polymer Science 135, no. 7: 1.
Franziska Wolny; Matthias Müller; Andreas Krause; Holger Neuhaus. Study of the bulk lifetime and material saturation current density of different p-type monocrystalline silicon materials. Energy Procedia 2017, 124, 235 -239.
AMA StyleFranziska Wolny, Matthias Müller, Andreas Krause, Holger Neuhaus. Study of the bulk lifetime and material saturation current density of different p-type monocrystalline silicon materials. Energy Procedia. 2017; 124 ():235-239.
Chicago/Turabian StyleFranziska Wolny; Matthias Müller; Andreas Krause; Holger Neuhaus. 2017. "Study of the bulk lifetime and material saturation current density of different p-type monocrystalline silicon materials." Energy Procedia 124, no. : 235-239.
Polyvinyl chloride (PVC)/bamboo composites have been prepared and assessed for their use in interior and exterior load-bearing applications. PVC composites were formed by compounding PVC with different bamboo particle sizes and loadings. The mechanical properties of these composites were determined at both ambient and elevated temperatures and after long-term water soaking. Analysis revealed that bamboo incorporation improved the PVC composite flexural modulus which was also observed with dynamic mechanical-thermal analysis on heating composites toca.70°C. Addition of 25% and 50% bamboo particles increases flexural modulus by 80% with dependency on whether fine (μm) or coarse (
Shahril Anuar Bahari; Warren J. Grigsby; Andreas Krause. Flexural Properties of PVC/Bamboo Composites under Static and Dynamic-Thermal Conditions: Effects of Composition and Water Absorption. International Journal of Polymer Science 2017, 2017, 1 -8.
AMA StyleShahril Anuar Bahari, Warren J. Grigsby, Andreas Krause. Flexural Properties of PVC/Bamboo Composites under Static and Dynamic-Thermal Conditions: Effects of Composition and Water Absorption. International Journal of Polymer Science. 2017; 2017 ():1-8.
Chicago/Turabian StyleShahril Anuar Bahari; Warren J. Grigsby; Andreas Krause. 2017. "Flexural Properties of PVC/Bamboo Composites under Static and Dynamic-Thermal Conditions: Effects of Composition and Water Absorption." International Journal of Polymer Science 2017, no. : 1-8.
Thermomechanical pulp (TMP), among other natural fibers, features characteristics that make it a promising candidate for the utilization in polymer composites. This review is providing an overview on the current state of research on TMP reinforced polymer composites. More than 50 references were reviewed. The cited literature is catalogued according to pretreatments, batch or continuous procedures, processing at laboratory or industrial scale, fiber contents, polymer types, coupling agents as well as wood species. The reinforcing potential of TMP utilized in composites is demonstrated. Tensile strength was found to be peaking at a fiber content of around 40 wt %. Fiber morphology is presumed to be an important determinator for composite properties. Specific mechanical energy [kWh/kg] is presented as an indicator suitable to compare the influence of various processes on fiber morphology. Furthermore, the feed-in and dosing issue that generally accompanies the utilization of cellulosic fibers is described and possible solutions are discussed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45161.
Oliver Mertens; Julius Gurr; Andreas Krause. The utilization of thermomechanical pulp fibers in WPC: A review. Journal of Applied Polymer Science 2017, 134, 1 .
AMA StyleOliver Mertens, Julius Gurr, Andreas Krause. The utilization of thermomechanical pulp fibers in WPC: A review. Journal of Applied Polymer Science. 2017; 134 (31):1.
Chicago/Turabian StyleOliver Mertens; Julius Gurr; Andreas Krause. 2017. "The utilization of thermomechanical pulp fibers in WPC: A review." Journal of Applied Polymer Science 134, no. 31: 1.
Polyvinyl chloride (PVC) was mixed with bamboo (Bambusa vulgaris) particle and additives by using PVC composite manufacturing system including initial dry blending with hot-cool mixing, followed by granulation via counter-rotating extrusion, and then consolidation by compression moulding to produce compression moulded board (CMB). The effects of different bamboo particle size (75 µm and 1 mm), bamboo particle loading (25 and 50% loading ratio), and differing processing lubricants content level (compositions 1 and 2) on the thermal stability of the composites were determined. Results show no significant trends in glass transition temperature (Tg) between dry blends, granules, and CMB, and between B. vulgaris particle loading at the respective processing steps. For samples with higher lubricant contents, the PVC Tg was observed to decrease up to 5 °C, possibly due to the reduced melt viscosity. The thermal decomposition temperature at 5% mass loss (T−5%) appeared to decrease from dry blend to CMB due to sample degradation on further processing at higher temperatures. The use of 50% B. vulgaris particle loading also reduced the T−5% values, assignable to bamboo particle degradation caused by the high processing temperatures. For oxidative induction time (OIT) testing, only granules and CMB from pure PVC composites system showed measurable oxidative times compared with OIT profiles of PVC/B. vulgaris composites system, suggestive of comparatively stabilized thermoplastic composites. This revealed that processing with bamboo particles does not contribute to degradation of PVC composites.
Shahril Anuar Bahari; Warren Grigsby; Andreas Krause. Thermal stability of processed PVC/bamboo blends: effect of compounding procedures. European Journal of Wood and Wood Products 2017, 75, 147 -159.
AMA StyleShahril Anuar Bahari, Warren Grigsby, Andreas Krause. Thermal stability of processed PVC/bamboo blends: effect of compounding procedures. European Journal of Wood and Wood Products. 2017; 75 (2):147-159.
Chicago/Turabian StyleShahril Anuar Bahari; Warren Grigsby; Andreas Krause. 2017. "Thermal stability of processed PVC/bamboo blends: effect of compounding procedures." European Journal of Wood and Wood Products 75, no. 2: 147-159.
Analysis of particles size distribution of Malaysian bamboo species (Bambusa vulgaris and Schizostachyum brachycladum) for polyvinyl chloride (PVC) composites production was conducted using dynamic image analysis (DIA). A wide distribution of bamboo particles length was recorded, varying from almost 0 to 1500-µm for both species. Inadequate amount of actual particles length distribution from each sieve size (75-µm and 1-mm) was also recorded. DIA observed an increase of aspect ratio from small to large particles, and fine particles were recorded to be slightly elongated than the large ones. However, the effects of bamboo particles size on the finished PVC composites performance were uncertain, considerable of numerous other factors that influence the performance. Only impact and water uptake properties of composites have been obviously affected by different particles size. Greater modulus value is observed in composites with high particles loading, though low impact strength and water resistance were recorded. The incorporation of high concentration of selected processing lubricants in the composites formulation helped to improve the impact and water resistance of the composites. Malaysian bamboo particles-PVC composites performance between different species was equivalent, demonstrated that both species displayed identical behaviour for composites production.
Shahril Anuar Bahari; Andreas Krause. Bamboo Particles-Polyvinyl Chloride Composites: Analysis of Particles Size Distribution and Composites Performance. Journal of Materials Science Research 2017, 6, p1 .
AMA StyleShahril Anuar Bahari, Andreas Krause. Bamboo Particles-Polyvinyl Chloride Composites: Analysis of Particles Size Distribution and Composites Performance. Journal of Materials Science Research. 2017; 6 (2):p1.
Chicago/Turabian StyleShahril Anuar Bahari; Andreas Krause. 2017. "Bamboo Particles-Polyvinyl Chloride Composites: Analysis of Particles Size Distribution and Composites Performance." Journal of Materials Science Research 6, no. 2: p1.