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Bin Li - One of the best experts on this subject based on the ideXlab platform.

  • cellulose nanocrystals prepared via formic acid hydrolysis followed by tempo mediated oxidation
    Carbohydrate Polymers, 2015
    Co-Authors: Wenyang Xu, Dennis Kronlund, Jan Henrik Smått, Stefan Willför, Xindong Mu, Anni Maattanen, Jouko Peltonen, Bin Li, Chunlin Xu
    Abstract:

    Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached Chemical Pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc.

Chunlin Xu - One of the best experts on this subject based on the ideXlab platform.

  • cellulose nanocrystals prepared via formic acid hydrolysis followed by tempo mediated oxidation
    Carbohydrate Polymers, 2015
    Co-Authors: Wenyang Xu, Dennis Kronlund, Jan Henrik Smått, Stefan Willför, Xindong Mu, Anni Maattanen, Jouko Peltonen, Bin Li, Chunlin Xu
    Abstract:

    Cellulose nanocrystals (CNCs) as a renewable and biodegradable nanomaterial have wide application value. In this work, CNCs were extracted from bleached Chemical Pulp using two stages of isolation (i.e. formic acid (FA) hydrolysis and 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) mediated oxidation) under mild conditions. In the first stage, FA was used to remove hemicellulose, swell cellulose fibers, and release CNCs. The FA could be readily recovered and reused. In the second stage, the CNCs isolated by FA were further modified by TEMPO-mediated oxidation to increase the surface charge of CNCs. It was found that the modified CNCs with more ordered crystal structure and higher surface charge had better redispersibility and higher viscosity in aqueous phase. Therefore, the modified CNCs could be more effective when used as rheology modifier in the fields of water based coating, paint, food etc.

Antonio Scipioni - One of the best experts on this subject based on the ideXlab platform.

  • integration of water footprint accounting and costs for optimal Chemical Pulp supply mix in paper industry
    Journal of Cleaner Production, 2014
    Co-Authors: Alessandro Manzardo, Antonio Piantella, Anna Mazzi, Andrea Fedele, Antonio Scipioni
    Abstract:

    Abstract Chemical Pulp is one of the most important raw materials used in the paper industry. This material is known to make a significant contribution to the water footprint and cost of final paper products; therefore, Chemical Pulp is crucial in determining the competitiveness of final products'. Several studies have focused on these aspects, but there have been no previous reports on the integrated application of raw material water footprint accounting and costs in the definition of the optimal supply mix of Chemical Pulps from different countries. The current models that have been applied specifically to the paper industry are based mainly on general sectorial data; therefore, they cannot reflect the importance of the efficiency of the different processes in the supply chain of paper production. The objective of this study was to develop a multi-objective optimization model to identify the supply mix that minimizes the water footprint accounting results and costs of Chemical Pulp, thereby facilitating the assessment of the water footprint by accounting for different Chemical Pulps purchased from various suppliers, with a focus on the efficiency of the production process. Water footprint accounting was adapted to better represent the efficiency of Pulp and paper production. A multi-objective model for supply mix optimization was also developed using multi-criteria decision analysis (MCDA). Water footprint accounting confirmed the importance of the production efficiency of Chemical Pulp, which affected the final results, with an average factor of 4.7 m 3 wood/t paper. The MCDA that we developed was used to determine the optimal mix of Chemical Pulps from different countries, which demonstrated how the optimal mix changed when considering only one of the two variables. Herein, we also discuss the latest developments in impact assessments related to water based on a life cycle assessment, which should be used as a framework for the future development of the model that is presented.

Tapani Vuorinen - One of the best experts on this subject based on the ideXlab platform.

  • PROPOSED NANO-SCALE COALESCENCE OF CELLULOSE IN Chemical Pulp FIBERS DURING TECHNICAL TREATMENTS
    BioResources, 2012
    Co-Authors: Raili Pönni, Tapani Vuorinen, Eero Kontturi
    Abstract:

    This review summarizes the proposed mechanisms for irreversible coalescence of cellulose microfibrils within fibers during various common industrial treatments for Chemical Pulp fibers as well as the methods to evaluate it. It is a phenomenon vital for cellulose accessibility but still under considerable debate. The proposed coalescence mechanisms include irreversible hydrogen bonding. Coalescence is induced by high temperature and by the absence of obstructing molecules, such as water, hemicelluloses, and lignin. The typical industrial processes, in the course of which nano-scale coalescence and possible aggregation of cellulose microfibrillar elements occurs, are drying and Chemical Pulping. Coalescence reduces cellulose accessibility and therefore, in several instances, the quality of cellulose as a raw material for novel products. The degree of coalescence also affects the processing and the quality of the products. For traditional paper-based products, the loss of strength properties is a major disadvantage. Some properties lost during coalescence can be restored to a certain extent by, e.g., beating. Several factors, such as charge, have an influence on the intensity of the coalescence. The evaluation of the phenomenon is commonly conducted by water retention value measurements. Other techniques, such as deuteration combined with FTIR spectroscopy, are being applied for better understanding of the changes in cellulose accessibility.

  • A Model for Chlorine Dioxide Delignification of Chemical Pulp
    Journal of Wood Chemistry and Technology, 2010
    Co-Authors: Ville Tarvo, Tuula Lehtimaa, Susanna Kuitunen, Ville Alopaeus, Tapani Vuorinen, Juhani Aittamaa
    Abstract:

    Abstract A phenomenon based model for chlorine dioxide delignification of Chemical Pulp is introduced. The Pulp suspension environment is modeled using the concept of two liquid phases, one inside and the other external to the fiber wall. Physico-Chemical processes taking place during delignification are implemented with thermodynamic, mass transfer and reaction kinetic models. A broad library of Chemical reactions is introduced. Inclusion of each reaction is justified. The model response is tested against experimental laboratory delignification results (o-delignified birch Pulp). The experimental data consists of kappa number, hexenuronic acid, inorganic oxy-chlorine compound, and organochlorine (AOX, OX) measurements at several time points during five delignification experiments. The model predictions are mainly in good agreement with the experimental results. The predictions regarding hypochlorous acid driven processes (HexA removal, organochlorine formation, chlorite and chlorate concentration) are so...

  • indirect evidence of supramolecular changes within cellulose microfibrils of Chemical Pulp fibers upon drying
    Cellulose, 2009
    Co-Authors: Eero Kontturi, Tapani Vuorinen
    Abstract:

    Dried and never-dried Chemical Pulps were subjected to strong sulfuric acid hydrolysis and the dimensions of the resulting cellulose nanocrystals (CNCs) were characterized by AFM image analysis. Although the average length of CNCs was fairly similar in all samples (55–65 nm), the length distribution histograms revealed that a higher number of longer crystals and a lower number of shorter crystals were present in the CNC suspensions prepared from never-dried Pulps. The distinction was hypothetically ascribed to tensions building in individual cellulose microfibrils upon drying, resulting in irreversible supramolecular changes in the amorphous regions. The amorphous regions shaped by tensions were deemed as more susceptible to acid hydrolysis.

Lei Li-rong - One of the best experts on this subject based on the ideXlab platform.

  • Study on Fibre Properties of Wheat Straw Semi-Chemical Pulp with Disintegration and Refining Treatment
    2008
    Co-Authors: Lei Li-rong
    Abstract:

    Low-consistency disintegration and high-consistency refining of wheat straw semi-Chemical Pulp were studied in the paper. The purpose was to provide theoretical understanding and a new Pulping technology for wheat straw semi-Chemical Pulp. Results showed that wheat straw Pulp was disintegrated to fibre bundles under low-consistency of 3%~4%,and sigle fibre was produced by refining treatment at higher consistency of 6%~7% . The analysis of fibre morphology,fibre length and sheet property indicated that the cutting effect of fibre was reduced and fibre length was well preserved with low-consistency disintegration and high-consistency refining process, which improved the sheet properties.