Paper and cardboard are porous, fibrous and natural materials which, without the application of one or more barrier layers, are of limited suitability for the packaging of e.g. foodstuffs, cosmetics or medicines. Sufficient barrier properties against various media and substances, such as oxygen, water vapor, aromas, fatty and oily substances, are an important factor in successfully using paper as a packaging material in a broader range of applications. Therefore, paper and board are often (extrusion)coated with synthetic (petrochemical) polymers that are non-biodegradable and difficult to recycle. In recent years, there has been intensive research to use bio-based materials as a functional barrier in the production of paper and board, thereby partially or completely replacing petroleum-based materials. This has mostly involved the use of existing coating technologies for paper and board, such as a film press (for water-based coatings) or extrusion (for thermoplastic coatings). These efforts have had limited success because, on the one hand, biobased coating materials are currently only available on the market to a limited extent and, on the other hand, it has often been technically and technologically impossible to process biopolymers in the same way as the conventionally used synthetic materials.
In this project, barrier coating with biopolymers using spray technology is investigated to explore a new way of paper surface functionalization.The working hypothesis, based on an extensive literature review and our own preliminary work, is that spray coating of paper and board with biopolymers is an economical, flexible and easy-to-integrate process into paper production and processing that can enable the production of plastic-free, paper-based and sustainable packaging materials, and in this respect is superior to currently used production processes. The objectives of the project are to scientifically investigate spray coating technology as a versatile coating process for the functional surface coating of paper and board with biopolymers and to explore the behavior of bio-based barrier materials in this process. In order to systematically explore the applicability of spray coating technology as a potential coating process for biobased barrier materials, important process parameters, such as droplet formation, droplet impact, homogeneity of the spray jet and wetting of the paper surface with the droplets, will be investigated as a function of the material used, rheology and solids content. Due to the possibility of application of biopolymers in addition to existing coating processes, multiple surface-coated concepts will also be investigated, which could markedly improve barrier properties (water vapor, grease, oxygen...). In addition to a comprehensive analysis of barrier and processing properties, the packaging materials produced in this way will also be evaluated in terms of recyclability and compostability, thus enabling the further development of completely plastic-free packaging materials purely from renewable and natural raw materials.
Project on novel membranes for flow batteries.
Nowadays, our world is dominated by smart technologies, which massively influence our daily life. However, there is a natural and sustainable resource that has improved our way of living for a much longer time. Throughout history, wood has been an important construction material. Separating wood into its smallest fragments ‒ lignocellulosic fibers (LCFs) ‒ and treating them, leads to products which are connected to our everyday needs: paper, having transferred the written word through time, is a classic in many forms, and paperboard as a reliable packaging material ensures the comfort of online shopping and food delivery.
Though the applications differ widely, the base material is always the same. An LCF has a complex hierarchical structure, which consists of several layers. The fiber shape can be imagined as a hollow cylindrical tube with pointed ends. While a tree trunk is massive, single LCFs are delicate. With 1-5 millimeters in length and a diameter of tens of micrometer (like a single hair), handling of single LCFs is not easy.
These characteristics result in a lack of available experimental methods which can provide a detailed characterization of the fibers’ mechanical and structural properties. Since LCFs are the key component of many products, knowledge of their mechanical behavior is essential for improvements. Simply put: If the same mechanical performance can be obtained with less LCFs, less trees need to be cut down. Furthermore, modeling of fiber networks has gained importance and with increasing complexity of the models, the demand for experimental data that accurately represents the fiber’s behavior is rising.
Here, the limits of mechanical techniques (MT) for single LCFs like tensile testing and nanoindentation will be overcome by implementing Brillouin light scattering microspectroscopy (BLSM) as an optical, non-contact method. BLSM is based on the inelastic scattering of light. Laser light is interacting with acoustic phonons, which causes a frequency shift of the Brillouin scattering peaks that can be related to the elastic properties of the LCFs. In a tensile test, it is only possible to access the mechanical properties in the testing direction, which is not sufficient for LCFs because they are anisotropic. BLSM enables the measurement of the full set of elastic constants in all three dimensions.
Initially, BLSM will be adapted for LCFs by studying simple cellulosic materials and linking BLSM results to MT findings. In a next step, structural and moisture-induced changes in LCFs will be investigated. The measurement of elastic constants of LCFs with BLSM and their comparison to those known from MT will be essential. Furthermore, the suitability of BLSM data for fiber and fiber network models will be explored. Overall, it is expected that the implementation of BLSM within this project will shine a light on the micromechanical behavior of LCFs and will result in an improved understanding of their performance.
The pulp and paper industry may serve as a backbone in the change from a fossil-based into a bio-based economy. Already today beside the main product cellulose, tall oil, turpentine and energy are produced. However, the potential is much higher and therefore cascade raw material utilization targeting bulk chemicals like acetic acid, formic acid or lactic acid needs to be addressed.
To address the topic of an increased use of wood in the way of cascade raw material utilization in the pulp- and paper industry, an ambitious consortium from national and international partners consolidated. Focus of the project is to isolate carboxylic acid from side streams of the KRAFT process, especially from the pulping process before the remaining stream is used for energy utilization.
Goal of the project is the development of a multi-stage process for the isolation of carboxylic acids from kraft pulping. Besides the isolation the optimization of the acid concentration in the regarded streams is investigated. Based on the results of the optimized acid concentration and a technology check for potentially used technologies a concept for further process integration shall be developed.
Im FlowBattMonitor entwickeln wir ein adaptives Batteriemanagementsystem für einen vanillinbasierten Flow-Batterie Forschungsdemonstrator mit 5kW / 20 kWh, der an der TU Graz installiert werden soll. Dieser wird mit einer Vielzahl an Sensoren und Mess- und Regelungstechnik ausgestattet, die es erlaubt alle relevanten Parameter zu erfassen, die für den Betrieb der Batterie notwendig sind. Dies umfasst den State of Charge, den State of Health, die Detektion von Fehlern im Hydrauliksystem, die Bestimmung der Energieeffizienz und der Coulomb-Effizienz, die Überwachung der Stack-Spannung und die Überwachung der Stack-Temperatur mittels dafür geeigneter Sensoren und Messtechnik Die daraus erhaltenen Daten werden in Modelle gefüttert, die schlussendlich zu einem virtuellen Abbild der Batterie führen und dessen Betriebszustand quasi voraussagen kann. Diese Abbilder, oft auch digitale Zwillinge genannt, sind Bereits im Einsatz in der Energiewirtschaft. Sie wurden unseres Wissens allerdings noch nicht für Flow Batterien realisiert, weder für organische oder anorganische Systeme. Der Nutzen der erhaltenen Ergebnisse liegt darin, dass der im Projekt installierte Demonstrator beliebig modular erweiterbar ist und in zukünftigen Projekten und Initiativen weiterverwendet werden kann. Dies ist von insbesonderem Interesse für die zukünftige Etablierung des Innovationscampus Inffeldgasse, um einen klimaneutralen Campus zu erreichen.
The CD Laboratory for Fiber Swelling and Paper Performance has four industrial partners: is aimed on fiber swelling and its effect on three aspects of fiber network performance. There are three key research areas.
LIQUID ABSORPTION. Here the kinetics of liquid absorption on a short timescale are investigated. This is related to the ink setting during printing, which is critical in high speed inkjet.
DIMENSIONAL STABILITY OF FIBER NETWORKS. the effect of liquid absorption on the dimensional stability of paper is addressed. The paper has to absorb the ink during printing, which may lead to deformations like buckling or curling of the paper. Modifications of fiber and paper to reduce deformations and improve dimensional stability are investigated. The expansion of fiber networks under load is also of interes for viscose fiber producers as hygiene products like tampons are taking up the liquid by expansion of the fiber network.
FIBER NETWORK MECHANICS. Primary aim of the research is to develop a fundamental understanding of the network mechanics on a fiber leven and on the network level. Micrometchanical testing of fiber properties is carried out and used to develop constitutive material models on the fiber- and on the network level. The effect of moistioning and drying process on the mechanical behavior of the paper during printing and converting is investigated in order to better understand and improve the industrial processes. Apart from that it is the aim to work out strategies to improve the mechanical performance of paper, i.e. paper strength.
In this project analytical methods for in depth characterisation of 3D-structural properties of tissue paper will be developed. These methods shall allow to correlate integral paper properties like tissue softness and water uptake to 3D-structural properties of the paper like topography, bulk and compressibility. Thereby we want to achieve a better understanding concerning the impact of certain changes in paper structure on the relevant product properties. These analytical methods will than be applied to assist the project partner in the development of advanced technologies for the production of premium tissue qualities (textured qualities, TAD-qualities).
IonMem is a protoype research project, which deals with the desig and the construction of a device, capable to continuously produce cellulose based membranes for energy storage applications.
Redox flow batteries are an emerging technology for medium and large-scale stationary energy storage and are considered as a viable option to buffer fluctuations in the energy grid. These fluctuations are caused by the increasing share of renewable energy (e.g. solar and wind energy) whose production is dependent on weather and seasonal conditions.
The core elements of a redox flow battery (RFB) are two tanks filled with the electrolytes. Currently used electrolytes feature several issues such as limited regional availability, stability, volatile price, lack of sustainability and – often neglected – significant toxicity. In SABATLE, we aim at investigating the safety and (nano)toxicity aspects of current and emerging electrolytes in redox flow batteries as well as the corresponding environmental impacts by performing a life cycle assessment of the whole life cycle from resource extraction to the end-of-life. We will investigate electrolytes from the following commercially available RFB technologies: vanadium, zinc-bromine/chlorine, iron, and compare them to emerging electrolytes based on organic compounds derived from lignins, so called quinones, currently being developed at one of the partners. The lignins as well as decomposition products of the electrolytes may contain also nanoparticles which may pose an additional risk for the environment. Human toxicity and ecotoxicity of electrolyte solutions will be assessed using algae, daphnia, and zebrafish biological models. Exposure scenarios upon accidents during operation of the battery and after end-of-life will be considered, and realistic doses for human exposure and ecotoxicity will be developed. Further, high impact will be generated by developing a tailored safe-and-sustainable-by-design (SaSbD) concept. Through the implementation of this concept a mitigation of potential hazards will be secured and more sustainable and inherently safe electrolytes will be provided. Public concerns, including risk assessment and stakeholder engagement will be covered in the project.
Pulp and paper production is a large industrial sector in Austria with many mills currently implementing more efficient and environmentally friendly technologies. Among these efforts, the great potential of enzyme applications in several crucial process steps has been demonstrated already in the past. Our project FibreZyme focuses on the more targeted use of enzymes in refining, deinking and viscosity adjustment by providing a better understanding of enzyme mechanisms on cellulose fibres and their influence on fibre and paper properties. The results of FibreZyme include detailed mechanistic knowledge on the action of purified enzymes and their combinations on cellulose fibres and suitable process control strategies based on that knowledge. From these findings company partners should be able to choose suitable enzyme formulations based on the developed knowledge and implement application into their different individual processes.
FibreNet will train young fibre-professionals having multidisciplinary view to develop sustainable bio-based fibre products with tailored properties for different application fields in both academic and non-academic sectors. Bio-based fibre products are one of the corner-stones in the European bio-based industry corresponding to 12% of the employment in manufacturing.
The industry, including such sectors as packaging, paper, biocomposites and biomedical and hygienic textiles, is currently
undergoing a fundamental transformation in order to respond to the competition raised i) by low-wage countries and ii) by
fossil-based materials. A common consensus in Europe is that to remain competitive and sustain the bio-based fibre
industries in Europe, we should focus on developing new high added value products that have specific functionalities but
reduced environmental impacts.
In fibre-based products, developing new properties and improving the performance are, however, typically long and timeconsuming processes. They usually involve massive and expensive laboratory and pilot-scale trials, which are followed by
statistical analyses. There is a particular knowledge gap in understanding the influence of fibre and fibre interface propertieson the mechanical properties of the end-product especially when developing products with tailored performance and functionalities. In addition to the research gap, there is a training gap in Europe, as we do not currently have a training
programme which would educate professionals having a skill set needed for the fibre-centered approach that we propose in
FibreNet.
To fill the research and training gaps, we propose here a unique training and research network which provides and further
develops knowhow, methods and tools in functionalization, characterization, numerical modelling and production of biobased fibre products at multiple length scales. The network covers expertise on packaging, paper, biocomposites and
biomedical textiles.
The pulp and paper industry may serve as a backbone in the change from a fossil-based into a bio-based economy. Already today beside the main product cellulose, tall oil, turpentine and energy are produced. However, the potential is much higher and therefore cascade raw material utilization targeting bulk chemicals like acetic acid, formic acid or lactic acid needs to be addressed.
To address the topic of an increased use of wood in the way of cascade raw material utilization in the pulp- and paper industry, an ambitious consortium from national and international partners consolidated. Focus of the project is to isolate carboxylic acid from side streams of the KRAFT process, especially from the pulping process before the remaining stream is used for energy utilization.
Goal of the project is the development of a multi-stage process for the isolation of carboxylic acids from kraft pulping. Besides the isolation the opitmization of the acid concentration in the regarded streams is investigated. Based on the results of the optimized acid concentration and a technology check for potentially used technologies a concept for further process integration shall be developed.
Securing competitiveness and employment are today’s most pressing topics of the Austrian pulp and paper industry: due to drastic changes in consumer behaviour and increased raw material costs, its economic situation has become more challenging. Research and development activities are key to face these economic challenges, and to strengthen Austria’s role in a changing global market.
The Austrian and European pulp and paper industry has therefore started a number of long-term research activities to ensure profitability. These activities aim on steering the industry into the leading position of a future bio-based industry. By using the most important non-food renewable raw material, i.e., wood, the pulp and paper industry has excellent prerequisites to realize this vision. In fact, the first steps have been already made: today’s pulping and bleaching processes no longer aim on cellulosic fibres and paper as sole products. These processes are already integrated with production routes for electricity, thermal energy, and bio-based chemicals (e.g., tall oil). Thus, the nucleus of a modern biorefinery that produces a variety of novel wood-based products has already formed in Austria’s pulp and paper industry. However, advanced biorefineries must use chemical and energy resources even more efficiently in order to be competitive. It is evident that such endeavours can only be successful if they are knowledge-based – reflecting the knowledge-based bioeconomy concept – and accompanied by concerted research efforts.
The proposed K-Project Flippr² - Future Lignin and Pulp Processing Research PROCESS INTEGRATION focusses its efforts on integrated solutions to efficiently manufacture value-added products from wood. Specifically, side streams available in pulp and paper mills, i.e., technical lignin from spent liquor and fines from pulp, will drive Flippr² activities. Our research programm consists of closely interlinked topics, which are all related to the complex process steps in future biorefineries: separation, fractionation, modification and recovery. Developing these processes, integrating them into the complex setting of a pulp and paper mill, as well as making these processes as efficient as possible requires an interdisciplinary approach: chemists, engineers, fibre specialists, wood technologists, biochemists and economists must act in concert. Expertise and excellence in all of these disciplines is necessary to understand, transform and expand existing process steps of the pulp and paper industry into an advanced and efficient biorefinery. A mixture of completely new methods, as well as cutting-edge technologies are employed to achieve the goals defined in Flippr²’s research program. In addition, special preparation steps are investigated to steer the characteristics of the obtained materials such that they fit value-added applications.
Flippr² is structured in two highly interconnected areas of precompetitive scientific research focusing on spent liquor utilization, and fibre fines utilization. The technical research work is complemented by an integrated life-cycle assessment to verify economic and environmental effects of the developed innovations.
Cellulose fibers will be investigated for energy storage systems.
Use of starch in the paper industry should be optimized.
Lignocellulosic biomass contains large amounts of lignin and therefore it is one of the most unexploited resources so far. Despite its fascinating materials properties, large scale applications that use lignin have not been realized yet and nowadays a large proportion is burnt (98%). The main problem to use lignins is their inhomogeneous composition causing problems in continuous processes which usually require relatively constant raw material quality. Nevertheless, the low material price, its excellent ecological fingerprint combined with interesting intrinsic properties such redox activity would make lignins versatile starting materials in a wide range of applications. The approach in Lignobatt is to use lignin as electrolyte in redox-flow batteries. Such battery systems require large volumes of material and would therefore generate a large market for lignins.
The development and adoption of renewable and sustainable energy and the production of materials based on based on biomass in biorefineries has become a top priority in Europe, and is Horizon 2020’s most prominent theme. Research in this field is required to reduce humanity’s carbon footprint, and is reliant upon a flow of newly qualified persons in these areas. Biorefineries are the core of several important European policies, from the Strategic Energy Technology Plan Roadmap on Education and Training (SET-Plan) to the European Bioeconomy Strategy. European development in this prioritised field is stalled due to a lack of qualified personnel and poor linkage between professional training and industry needs. To address these problems, BioEnergyTrain brings together fifteen partners from six EU countries to create two new post-graduate level curricula (“Biorefinery Engineering” and “Bioresource Value Chain Mangagement”) and a network of tertiary education institutions, research centres, professional associations, and industry stakeholders encompassing the whole value chain of biorefineries.
Packaging materials have to have a sufficient barrier function aginst various substances with the required barrier function being dependent on the packed material. For food packaging additional requirements from the side of legistlation regarding migration limits for varous substances and substance classes have to be observed.
Due to their porous network structure paper and board have only a limited barrier functions against liquids and gases and therefore are often extrusion coated or laminated with various synthtetic Polymers. These compounds however are not biodegradable any more and recycling of the materials is difficult.
Before this background the target of the project BARRIERPAPER is to evaluate the barriere function of a multitude of novel biobased barrier materials (e.g. nanocelluloses, PLA and PHB dispersions etc.) regarding applicability in the paper industry in order to create a solid basis for new developments in the field of paper based barrier packaging materials, which on one hand comply to market requirements and regulatory requirements and on the other hand can be applied to the paper substrates using surface treatment equipment available in the paper industry. The focus on biobased materials on a sustainable substrate shuch as paper should allow an increased use of sustainable materials in the papckaging sector.
An important part in this project is the evaluation of barrier materials from a food-analyitical viewpoint by evaluation of the permeation of defined substances and substance classes through the various barrier materials to come to a comprehensive understanding of the permeation mechanism.
In this project, the thermal properties of cellulose should be improved.
In this project, barrier propeties of various papers will be investigated. In this context, different chemical and physical propeties of the papers will be elucidated.
The retention aids used in the paper industry are in large part cationic polymers of high molecular weight. Their effect depends to a large extent on induced shear after dosage. The emerging flocs and even the polymer itself can be destroyed by the induced shear. To evaluate this effect of shear and also of retention time an already available prototype for simultaneous industrially relevant measurement of formation, retention and dewatering shall be equipped with a shear reactor capable of inducing variable and defined shear in the industrial scale on the suspension in the approach flow.
Energy supply and climate change are todays most pressing preoccupations. Promoting renewable materials certainly is the most efficient way to improve sustainability in resource use. In this context the pulp and paper industry is well placed as it is based on one of the most important renewable raw materials wood. While novel wood based biorefinery concepts have been in the focus of scientific research for quite some years, the integrated development of new products and their manufacturing within the pulp and paper industry still is to be seen as a major bottleneck with a great potential.
In this K-Project Future Lignin and Pulp Processing Research - FLIPPR, the efforts are focused on establishing structural know-how to make more efficient use of both major raw materials streams of the industry - cellulose and lignin. The single projects focus on applications in the pulp and paper value chain but also in areas outside the classical product chain. Product and process design in the pulp and paper industries are mostly empirical due to the underlying complexity of raw materials, processes and products. The goal of FLIPPR is to transform this empirical domain into a science-based endeavour and to give the current product and process development approaches in the field of lignin and fibre usage a new direction.
The respective expertise in pulp manufacturing (kraft, sulphite and mechanical pulping processes), paper production (wood free and mechanical graphic papers, packing
papers), process technology, analytical chemistry, pulp and paper chemistry, fibre and paper physics, coating technology, organic synthesis, enzymes and biotechnological strategies of the participating scientific and company partners complement each another ideally.
FLIPPR is structured in two highly interconnected areas of precompetitive scientific research focusing on lignin and fibre utilization and a third area with the general focus on technoeconomic assessment, LCA and project management. Within these areas a total of twelve projects will be carried out that will enable a more efficient use of the lignin and fibres from existing pulp and paper plants in the future.
Subprojects:
Titel: FLIPPR - Hydrogen-Shuttle - Assessment and evaluation of a thermo-chemical interface between pulp mill waste streams and petrol refinery feed streams, Contact: Schwaiger (01.11.2015 - 01.06.2016)
The Objectives of this study is to check the availability of waste streams (black liquor) from pulp mills for fuel and chemicals production without interference with current mill operation, moreover the evaluation of black liquor processing for fuel precursor separation on site of the pulp mills. Furthermore the logistic needs for (crude) fuel precursor transfer between pulp mills and petrol refineries will be estimated. The process evaluation for thermochemical conversion of pulp mill waste streams (black liquor) into refinery ready feed (crude fuel precursor) for fuel production is the main goal.
Titel: FLIPPR - Flow Fractionation, Contact: Radl, (01.09.2013 - 31.03.2017)
FLIPPR Flow Fractionation focuses on the assessment and development of fibre suspension separation processes.
The strength and stiffness properties of paper show a high degree of variation, since cellulosic fibers are highly heterogeneous on the microstructural level. These properties are mainly influenced by the strenght properties of single fibers and of the fiber-fiber joints in the fiber network. Futher the size and number of the bonding areas between the fibers is very important. Because of the hygroscopic behaviour of the wood polymers cellulose and hemmicelluloses the mechanical properties are also depending on moisture and temperature. The high degree of heterogeneity on the microstructural level and the high number of number of loading modes of fibers and fiber-fiber joints in paper make it almost impossible to analyze this behaviour using exclusively experimental methods. The application of analytical and numerical methods from the field of mechanics to evaluate the structure-property relationships of paper at different length scales is therefore of high interest. In this project micro-tensile and -stiffness test on fibers and fiber-fiber joints are combined with numerical modelling in order to determine the important parameters under varying failure modes. By combining novel experimental methods and modelling a better understanding of the structural/dynamical behaviour of paper and its behaviour under load will be obtained.
The project is aimed to identify the reasons for print quality problems of graphic papers and packaging papers. The research is focusing on digital printing and offset printing. The key research approach is to measure local paper properties in high resolution and subsequently link variations in paper properties to local variations in print density and missing ink transmission using statistical modeling. As a result we obtain the influence of different paper properties on printing problems.
Eine der größten Herausforderungen in der Papierherstellung ist die komplexe Abhängigkeit zwischen den drei Parametern Formation (lokale Masseverteilung im Papier), Retention von Faser-, Fein- und Füllstoffen im Blatt und gleichzeitiger Entwässerung der Papierbahn im Wet End der Papiermaschine.
The production of paper is very energy consuming, because a fibre suspension of 0.2% solids content has to be dewatered by mechanical or physical methods to 93% dry content. A comprehensive approach based on new scientific results on simulation and sensor technology will be applied to optimize all three steps of paper production, i.e. wet end, wet pressing and drying. The goals for increased energy efficiency set in the project Integrated Ecopaper are:
1.) Development of a new system of wet end chemicals and improved process water loop closing which will lead to energy savings on one hand by reducing the vacuum power demand for dewatering. On the other hand it increases the solids content of the paper after the wire section leading to a reduction of drying energy.
2.) Development of a wet pressing technology reducing felt vacuum conditioning energy by optimizing water distribution in the press felts. Furthermore it increases solids content after the press section leading to a further reduction of drying energy.
3.) Development of sensors and control systems for the drying section which are reducing start-up time by 30% and thus lowering specific energy consumption per startup by 2.5%. The project will increase energy efficiency in paper production by implementing new dewatering technologies. Improved process control lowers energy consumption by reducing overdrying of the paper, which then needs to be rewetted to meet the specified dry content.
Reducing energy consumption in the paper production process has great impact on the productions cost. The high complexity of the drying section and the heat recovery system of a paper machine gives a very large number of possible operator settings for paper drying. The aim of the research projects is development of a simulation tool that identifies optimized settings of the paper machine and thus enables reductions in energy consumption. The software simulates the physical processes of heat and mass transfer in the various aggragates of the paper machine (drying cylinders, IR dryer, impingement hood, heat exchangers, ventilations etc..). It delivers simulated values for the mass and heat fluxes in the papermachine as well as a heat balance.
The results from the simulation software are verified in industrial trials and the production process will be optimized accordingly. Furthermore a graphical user interface similar to the process control system in the papermill will be addad to the simulation software. The final software can then be used for further optimization work in the paper mill or for operator training,
used for operator training
A new Christian Doppler Laboratory for Surface Science Investigations on Paper Strength will investigate the strength of fiber fiber bonds in paper. The surface morphology as well as the surface chemistry will be investigated using a collaborative approach. The laboratory head is Prof. Robert Schennach from the Institute of Solid State Physics, Graz University of Technology. Close collaboration with Prof. Wolfgang Bauer from the Institute of Paper Pulp and Fiber Technology, Graz University of Technology and with Prof. Christian Teichert from the Institute of Physics, University of Leoben will enable a simultaneous investigation of the fiber morphology and the surface and interface chemistry. The industrial partner is Mondi Packaging in Frantschach.
Cross sectional fiber morphology plays a key role for mechanical and optical paper properties. Current methods for the measurement of cross sectional morphology of pulp fibers e.g. fiber wall thickness, fiber wall area, fiber collapse have serious limitations. First, they are not able to measure a statistically meaningful number of fibers with reasonable effort. Second, most of these methods evaluate the apparent shape of the fiber cross section because they do not take into account, that images of fiber cross sections are skewed if the fiber's main axis is not perpendicular to the image plane. This error can only be detected and eliminated if cross sectional properties are measured from 3D datasets of pulp fibers.
Therefore, the main goal of the proposed project is to develop an efficient procedure that permits statistically meaningful and correct analysis of fiber cross sectional properties from 3D datasets. In order to obtain statistical significance a large number of fibers has to be analyzed with reasonable effort. Digitization will be obtained by a fully automated procedure (recently developed in another project) delivering high resolution 3D datasets. The main innovation of the proposed research is development and validation of an efficient and correct measurement method. The key issue here is development of novel image analytical algorithms, which provide fully automated detection of the fiber cross sections and tracking of these cross sections through a sequence of slice images. Current solutions require a considerable amount of user interaction, making them time consuming and costly. Full automation of this step will eliminate the bottleneck of the measurement. This will enable serious quantitative research regarding the effect of fiber cross sectional morphology on paper properties and the effect of pulping and stock preparation on fiber cross sectional morphology.
A consistent method will be developed that restores the true fiber cross sectional shape from the apparent shape.
A sampling strategy is to be worked out, which ensures that measurement results of fiber populations are statistically representative.
The obtained results will be verified with other scientific measurement concepts based on confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM).
The new method will be used to research a previously hardly investigated subject:
Sequences of fiber images will be analyzed regarding the variation of the cross sectional properties like fiber collapse and wall dimensions. Inter-fiber variations have large impact on mechanical fiber properties like fiber flexibility, strength and conformability. Such analysis will thus provide novel data and identify a possibly important new aspect of fiber morphology.
The research will be carried out by two teams. The computer vision group will develop the image analysis part and the pulp and paper group will work out the fiber morphology part. The proposed project will continue the long lasting and fruitful cooperation between these two groups at Graz University of Technology.
Ermittlung und Visualisierung der 3D Mikrostruktur von Materialien und biomedizinischen Präparaten
Research on printability has increasingly focused on measurement methods that evaluate local paper properties, i.e. methods that deliver 2D paper property maps. These methods measure the local variations of paper properties and thus enable direct comparison to
local inhomogeneity (i.e. print mottle) or defects in the print. A
common approach is to register, i.e. to spatially align, an
image of the printed paper to paper property maps of the printed region. Such aligned maps enable quantitative analysis of interrelations between local paper properties and local print density, e.g. by point-wise correlation.
In the current research project we model the interrelation of local print reflectance to local properties of the
printed paper sample. For this purpose we analyze maps of
different local paper properties, e.g. variations in basis weight, surface topography, ink penetration, gloss and refractive index, which have been registered to maps of local print reflectance. We create statistical models using multiple linear regression, analyzing the degree of redundancy between the local paper properties and their interrelation to local print density. These models identify the key properties of paper causing printability problems.
Coating coverage and coating holdout (limited penetration of coating color into the base paper) are essential properties of coating layers. Almost all quality parameters of coated papers are influenced by these parameters. Of special interest are these properties for single coated papers and for the precoat of multiple coated papers. Different methods are used to characterize these properties. For example, the so called burnout-test is used to estimate the coating coverage. Paper cross sections, analyzed with scanning electron microscopy (SEM) or optical microscopy are used to estimate the penetration of coating color into the base paper. But all methods are limited in some way. SEM is limited by a small sample size and the results obtained do not represent the coating layer in total. The burnout test gives only relative results coating layer thickness cannot be determined accurately.
A method, developed at the Institute for Paper, Pulp and Fiber Technology of Graz University of Technology allows a representative analysis of coating structures of coated papers at high resolutions. The automated serial sectioning method STRUCSOP provides a 3D model of the investigated paper sample, which can be further processed with especially developed advanced image analysis routines.
This analysis routine will be used in this proposed research project to answer open questions regarding coating coverage and coating holdout. The main goal is the development of characteristic parameters, which can be used as a quality measure for coating layers. Paper samples of the project partners will be analyzed to characterize the effects of different coating formulations, coating application systems as well as the effect of pre- and post-calendering on coating structures.
The aim of this project is to develop and evaluate a method for applying drugs on paper carrier materials in laboratory as well as in industrial manufacturing processes. Active Pharmaceutical Ingredients (API) and additives are printed on paper using the drop-on-demand printing technology. The printed paper may then be inserted into a gelatine capsule for peroral applications or directly administered orally after additional modifications. The capabilities of various paper grades are evaluated with respect to the utilization as a pharmaceutical carrier material, considering the intended registration as a pharma-excipient. In addition, models are developed to describe the main phenomena during the printing process and to simulate application, impact, penetration and drying of fluids with porous materials.
All fundamental paper properties are basically determined by the three-dimensional distribution of the raw materials in the paper sheet. The structure of the main paper ingredients fiber, filler pigment and coating colour determines mechanical properties and penetration behaviour of liquids.
The research project is focused on the development of technology that extracts the structure of fibers, filler pigments and coating colour to build a three-dimensional model of the paper sheet. In order to achieve this, the paper is either split into layers or cut into thin slices. In these layers or slices the spatial distribution of fibers, fillers and coating colour is identified using digital image analysis. In that way it is possible to reconstruct a three dimensional model of paper samples.
The information about the tree dimensional paper structure is used to improve the paper production process in order to optimize paper properties, the focus is set to mechanical properties and print quality.
All fundamental paper properties are basically determined by the three-dimensional distribution of the raw materials in the paper sheet.The structure of the main paper ingredients fiber, filler pigment and coating colour determines mechanical properties and penetration behaviour of liquids. The research project is focused on the development of technology that extracts the structure of fibers, filler pigments and coating colour to build a three-dimensional model of the paper sheet. In order to achieve this, the paper is either split into layers or cut into thin slices. In these layers or slices the spatial distribution of fibers, fillers and coating colour is identified using digital image analysis. In that way it is possible to reconstruct a three dimensional model of paper samples. The information about the tree dimensional paper structure is used to improve the paper production process in order to optimize paper properties, the focus is set to mechanical properties and print quality.
Fibre flexibility is a pulp property of considerable importance in the manufacture of paper. It influences the behaviour of the pulp suspension, the drainage characteristics of the sheet forming process and the strength and optical properties of the final paper.
Despite the importance of this property there is no widely accepted method to measure fibre flexibility.
The intention is to develop a method to measure fibre flexibility directly on single fibres.
To get statistically significant results with reasonable effort the method has to be highly automatable.
Fibres in highly diluted suspension in a well defined flow profile are loaded with defined hydrodynamic forces. Pictures are taken with a high-speed-camera and the fibres are captured by image analysis.
The reaction of a fibre to the defined hydrodynamic load is used to calculate it´s flexibility.
With this method influences on fibre flexibility by processes like cooking, bleaching, beating or drying can be investigated and systematically improved.
The project aim is to investigate how far the deformation behaviour (short Z elasticity) of paper influences the refining and further processing quality in the direction of the bulking thickness in connection with surface topography.
* If deformation behaviour in Z direction and surface topography is strongly irregular, then a high volume and resistance loss in satinage and smoothing processes is expected.
* If papers with strong heterogeneity of its surface and its compressibility become printed an irregular print-out has to be expected.
* The coating of base papers with a heterogeneous compressibility results in an uneven coating layer with negative effects on the paper quality.
Classic deformation tests on papers are limited to measuring the compressibility between rollers or plates. The homogeneity of the deformation behaviour of papers in Z direction in resolution of microns cannot be examined by these methods.
It is aim of the project to measure and to evaluate the deformation behaviour in Z direction and the surface topography spatially. The effect of the z-elasticity on paper properties like smoothness, gloss, volume, stiffness and its influence on printability or post-processing processes like die cutting and folding are investigated.
The Z elasticity is result of the raw and auxiliary material choice and of the use of production and refining technologies. To be able to examine the complex interactions, multivariate statistical methods are used.
The project 'Rotogravure Printability and Structure Analysis of
SC-Paper' was aimed to explore the causes for print mottle of
gravure printed SC paper. The focus was set on the analysis of paper structure and identification of paper properties that cause print mottle. Five main fields of work have been adressed:
1.) Because of the low viscosity of the gravure printing ink
and the high ink absorption of SC paper, printing ink penetration has often been mentioned as a main reason for mottle. The main objectives are: a.) Development of a technique to measure local variations of printing ink
penetration. b.) Resolving the influence of printing ink penetration on print mottle.
2.) One of the main problems with print mottle is, that multiple interacting paper properties are involved in its occurrence. Often mentioned are for example formation, surface topography or printing ink penetration. The main objectives are: a.) Quantitative determination of the varying influence
factors. Which paper properties have major influence, which ones have minor influence? Which parameters do not have any effect at all? b.)Evaluation of measurement methods, in order to identify techniques relevant for mottle analysis and avoid irrelevant ones.
3.) Evaluation of printing dot size and amount of transferred ink
and its relation to mottle. Such analysis provides useful information: Is gravure mottle caused by varying amounts of
transferred ink or is it caused by differences in the ink preading
behavior of the individual printing dots?
4.) Not only the overall surface roughness and compressibility, but also local variations of these properties are generally believed to have an influence on print mottle. The influence of local roughness and compressibility variations on print quality was investigated.
5.) Analysis of industrial paper samples provided by the project
partners. Investigation of commercial samples provides practical applicability of the research results.
Alternative way for the refining of pulp.
The goal is to improve the pulp properties on the one hand, and to reduce the energy consumption on the other hand. not assigned KP: Papierindustrie im deutschsprachigen Raum
Driven by the results of earlier projects, the new target is to evaluate the amount of damage cellulosic fibers have taken by detecting changes in their swelling behaviour. Swelling is induced (or enhanced) by adding chemicals to pulp fibers. Afterwards, digital images of the highly diluted pulp suspension are taken by means of transmission microscopy. The degree of swelling of the single fibers is determined by applying image analysis algorithms which have been developed at this institute. The collected data of all fibers is then evaluated statistically.
Mechanical (or other, e.g. chemical, thermic) damage to pulp fibers will result in better access of swelling agents to the fiber wall, thus increasing the amount of swelling.
The goal of this project is to develope new methods to analyse the three dimensional structure of paper. It is planned to construct a flocculation cell to reveal the origins of different paper structures.
A better knowledge about the structure of paper enables improvements of sheet properties by means of specific changes during the papermaking process.
Paper sheets are being split using a laminating device. The fibers in each layer are detected using image analysis. The fibers are assigned to their position in the original sheet and aggregated into seperate volume elements. The local orientation in these elements is determined in order to find correlations to phenomena like paper cockle and dimensional instability. Samples from industrial papers are examined.
The other focus of the project is the measurement of the filler z-distribution in paper. Scanning electrone microscopy images are analyzed in order to determine the differences between kaolin z-distribution and calcium carbonate z-distribution.
New paper testing methods, partly using modern image analysis techniques, are applied in order to allow deeper understanding of the physical phenomenons influencing rotogravure printing results. Penetration phenomena of rotogravure inks into paper structure, z-directional deformation behaviour and surface characteristics are studied and new measurement techniques are developed. Image analysis techniques were also used to allow an objective evaluation of print quality. Using multivariate statistical techniques it was shown that penetration phenomena together with surface roughness and z-directional compressibility are to a large degree responsible for rotogravure printability results.
not assigned GG: Unternehmen der dt. Papier- und Druckindustrie
Analysis of paper's z direction with special reflection on formation and fiber orientation.
not assigned KP: Internationale Papierindustrie
not assigned KP: Österreichische Zellstoffindustrie