{"title":"Rheological investigation of complex micro and nanofibrillated cellulose (MNFC) suspensions: Discussion of flow curves and gel stability","authors":"M. Schenker, J. Schoelkopf, P. Mangin, P. Gane","doi":"10.32964/TJ15.6.405","DOIUrl":"https://doi.org/10.32964/TJ15.6.405","url":null,"abstract":"","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69473374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Shatkin, K. Ong, J. Ede, T. Wegner, Michael Goergen
: Commercialization of cellulose nanomaterials (CNs) is rapidly advancing, to the benefit of many end-use product sectors, and providing information about the safe manufacturing and handling for CNs is a priority. Safety Data Sheets (SDS) are required for industrially produced materials to communicate information on their potential health, fire, reactivity, and environmental hazards, and to provide recommendations on how to safely work with these materials. Cellulose and cellulose pulp, which have widespread commercial end uses, can create nuisance dusts when dried and are required to have SDS. We therefore expect that nanoscale forms of cellulose will also require SDS. This study identifies the currently available SDS information for CNs and highlights existing gaps in our knowledge. With U.S. and international adoption of the Globally Harmonized System (GHS) for Hazard Communication, producers are required to report SDS known data and data gaps. Given the novelty of all nanomaterials, it is preferable to fill these gaps in SDS as a demonstration of our commitment to the safe production and use of these materials. To evaluate the availability of SDS information and prepare for commercialization of CNs, we assessed available safety information for CNs to identify available GHS SDS data, data gaps, and what data need to yet be developed to fully classify CNs according to the GHS. Specifically, we report on the available data and gaps regarding the toxicological profile, environmental characteristics, physical and chemical properties, exposure controls, and personal protection for cellulose nanomaterials, to encourage the development of missing data and advance safe commercialization. Application: By providing information on available and missing data and research needed to communicate the safe handling and use of CNs according to the criteria set by the GHS for SDS, industry can demonstrate the safety of these materials, ensuring their maximum market potential is reached, and commercialization is not delayed because of uncertainties about safe use.
{"title":"Toward cellulose nanomaterial commercialization: knowledge gap analysis for safety data sheets according to the globally harmonized system","authors":"J. Shatkin, K. Ong, J. Ede, T. Wegner, Michael Goergen","doi":"10.32964/tj15.6.425","DOIUrl":"https://doi.org/10.32964/tj15.6.425","url":null,"abstract":": Commercialization of cellulose nanomaterials (CNs) is rapidly advancing, to the benefit of many end-use product sectors, and providing information about the safe manufacturing and handling for CNs is a priority. Safety Data Sheets (SDS) are required for industrially produced materials to communicate information on their potential health, fire, reactivity, and environmental hazards, and to provide recommendations on how to safely work with these materials. Cellulose and cellulose pulp, which have widespread commercial end uses, can create nuisance dusts when dried and are required to have SDS. We therefore expect that nanoscale forms of cellulose will also require SDS. This study identifies the currently available SDS information for CNs and highlights existing gaps in our knowledge. With U.S. and international adoption of the Globally Harmonized System (GHS) for Hazard Communication, producers are required to report SDS known data and data gaps. Given the novelty of all nanomaterials, it is preferable to fill these gaps in SDS as a demonstration of our commitment to the safe production and use of these materials. To evaluate the availability of SDS information and prepare for commercialization of CNs, we assessed available safety information for CNs to identify available GHS SDS data, data gaps, and what data need to yet be developed to fully classify CNs according to the GHS. Specifically, we report on the available data and gaps regarding the toxicological profile, environmental characteristics, physical and chemical properties, exposure controls, and personal protection for cellulose nanomaterials, to encourage the development of missing data and advance safe commercialization. Application: By providing information on available and missing data and research needed to communicate the safe handling and use of CNs according to the criteria set by the GHS for SDS, industry can demonstrate the safety of these materials, ensuring their maximum market potential is reached, and commercialization is not delayed because of uncertainties about safe use.","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69473391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cellulose nanofibrils (CNF) were successfully produced from a bleach kraft eucalyptus pulp by a supermasscolloider. Effects of grinding time on structure and properties of CNF and the corresponding CNF films were investigated. Grinding time was important to increase the optical transparency of CNF suspensions. The degree of polymerization (DP) and crystallinity index (CrI) of CNF decreased linearly with the increase in CNF suspension transparency. This suggests optical transparency of a CNF suspension can be used to characterize the degree of fibrillation. Specific tensile strength and Young’s modulus of the CNF films made of CNF suspension with only 0.5 h grinding were increased approximately 30% and 200%, respectively, compared with conventional handsheets prepared by valley beating to 300 Canadian Standard Freeness (CSF). Energy input was only 1.38 kWh/kg for 0.5 h grinding. Grinding beyond 0.5 h produced negligible improvement in specific tensile and specific modulus. Opacity of CNF films decreased rapidly during the first 1.5 h of fibrillation and then plateaued. Application: Disk milling time affects the morphology of cellulose nanofibrils as well as the optical and mechanical properties of film made of the resultant fibrils. Cellulose nanomaterials, such as cellulose nanofibrils (CNF) derived from renewable lignocelluloses, have attracted great interest recently. Lignocelluloses are available in nature in great abundance. Cellulose nanofibrils have been used for producing a range of functional materials including films, membranes, aerogels, scaffolds, and hybrid composites [1-4] and have the potential to replace a variety of materials derived from nonrenewable petroleum. Mechanical fibrillation remains the most common approach to produce CNF from lignocelluloses. Microgrinding has the potential for large-scale CNF production and has been widely used [5-9]. Microgrinding leads to a series of dramatic changes in fibers, such as internal fibrillation, external fibrillation, and fiber shortening. Continued fibrillation resulted in fragmentation of cell wall and produced microand nanofibrils [10]. The dominant factors that dictate nanocellulose material strength are the fibril length and fiber bonding. The orientation of bonds between nanoparticles is an important factor in tuning the Young’s modulus [11]. Increased grinding often results in increased bonding as a result of the fine materials produced that substantially increase fibril surface area. On the other hand, increased grinding time can also result in short fibrils simply because of mechanical actions. There is a tradeoff between increasing bonding and reducing fibril length with extended grinding; in other words, an optimal grinding time exists for producing CNF for polymer reinforcement. Unfortunately, such an understanding has not been well documented. The objective of the present study is to investigate the effects of mechanical fibrillation time on the properties of resultant CNF
{"title":"Effects of mechanical fibrillation time by disk grinding on the properties of cellulose nanofibrils","authors":"Quian Wang, J. Zhu","doi":"10.32964/TJ15.6.419","DOIUrl":"https://doi.org/10.32964/TJ15.6.419","url":null,"abstract":"Cellulose nanofibrils (CNF) were successfully produced from a bleach kraft eucalyptus pulp by a supermasscolloider. Effects of grinding time on structure and properties of CNF and the corresponding CNF films were investigated. Grinding time was important to increase the optical transparency of CNF suspensions. The degree of polymerization (DP) and crystallinity index (CrI) of CNF decreased linearly with the increase in CNF suspension transparency. This suggests optical transparency of a CNF suspension can be used to characterize the degree of fibrillation. Specific tensile strength and Young’s modulus of the CNF films made of CNF suspension with only 0.5 h grinding were increased approximately 30% and 200%, respectively, compared with conventional handsheets prepared by valley beating to 300 Canadian Standard Freeness (CSF). Energy input was only 1.38 kWh/kg for 0.5 h grinding. Grinding beyond 0.5 h produced negligible improvement in specific tensile and specific modulus. Opacity of CNF films decreased rapidly during the first 1.5 h of fibrillation and then plateaued. Application: Disk milling time affects the morphology of cellulose nanofibrils as well as the optical and mechanical properties of film made of the resultant fibrils. Cellulose nanomaterials, such as cellulose nanofibrils (CNF) derived from renewable lignocelluloses, have attracted great interest recently. Lignocelluloses are available in nature in great abundance. Cellulose nanofibrils have been used for producing a range of functional materials including films, membranes, aerogels, scaffolds, and hybrid composites [1-4] and have the potential to replace a variety of materials derived from nonrenewable petroleum. Mechanical fibrillation remains the most common approach to produce CNF from lignocelluloses. Microgrinding has the potential for large-scale CNF production and has been widely used [5-9]. Microgrinding leads to a series of dramatic changes in fibers, such as internal fibrillation, external fibrillation, and fiber shortening. Continued fibrillation resulted in fragmentation of cell wall and produced microand nanofibrils [10]. The dominant factors that dictate nanocellulose material strength are the fibril length and fiber bonding. The orientation of bonds between nanoparticles is an important factor in tuning the Young’s modulus [11]. Increased grinding often results in increased bonding as a result of the fine materials produced that substantially increase fibril surface area. On the other hand, increased grinding time can also result in short fibrils simply because of mechanical actions. There is a tradeoff between increasing bonding and reducing fibril length with extended grinding; in other words, an optimal grinding time exists for producing CNF for polymer reinforcement. Unfortunately, such an understanding has not been well documented. The objective of the present study is to investigate the effects of mechanical fibrillation time on the properties of resultant CNF ","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69473381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Hellström, A. Heijnesson-Hultén, M. Paulsson, H. Håkansson, U. Germgard
Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and e ...
{"title":"A comparative study of enzymatic and Fenton pretreatment applied to a birch kraft pulp used for MFC production in a pilot scale high-pressure homogenizer","authors":"P. Hellström, A. Heijnesson-Hultén, M. Paulsson, H. Håkansson, U. Germgard","doi":"10.32964/TJ15.6.375","DOIUrl":"https://doi.org/10.32964/TJ15.6.375","url":null,"abstract":"Microfibrillated cellulose (MFC) was produced in pilot scale from a bleached birch (Betula verrucosa) kraft pulp that was pretreated with either Fenton's reagent or with a combined mechanical and e ...","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69473359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Grégory Chauve, Damien Mauran, C. Fraschini, J. Bouchard
{"title":"Critical discussion on the thermal behavior of sulfated cellulose nanocrystals","authors":"Grégory Chauve, Damien Mauran, C. Fraschini, J. Bouchard","doi":"10.32964/tj15.6.383","DOIUrl":"https://doi.org/10.32964/tj15.6.383","url":null,"abstract":"","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69473364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ionic strength control of sulfated cellulose nanocrystal suspension viscosity","authors":"Stephanie Beck, J. Bouchard","doi":"10.32964/TJ15.6.363","DOIUrl":"https://doi.org/10.32964/TJ15.6.363","url":null,"abstract":"","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69472529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Screening the new process concepts for pulp mill retrofits with varying capacity constraints","authors":"P. Kangas","doi":"10.32964/TJ15.4.241","DOIUrl":"https://doi.org/10.32964/TJ15.4.241","url":null,"abstract":"","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69472469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of the work described in this thesis is to characterize the structure of coatings and prints, and to validate models for the optical response and interaction of ink and coating based on optical measurements of physical samples. It is the interactions between the printing ink and the porous structure of the coating layers that are subject to investigation. Experiments have been employed to relate the physical conditions in a flexographic printing nip to the ink setting and the resulting optical response.By comparing simulated and measured results, it was shown that modifications of the surface properties account for the brightness decrease when substrates are calendered. Light scattering simulations, taking into account the surface micro-roughness and the increase in the effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease, whereas the bulk light scattering and light absorption coefficients were not affected by calendering.Ink penetration affects the print density, mottling and dot gain. Results show that ink distribution is strongly affected by surface roughness, differences in pore size and pore size distribution. For samples having different latex amounts and different latex particle sizes, a higher print force did not increase the depth of penetrated ink to any great extent, but rather allowed the wetting to act more efficiently with a more evenly distributed ink film, a higher print density and fewer uncovered areas as a result. Uncovered areas could be linked both to local roughness variations and to local wettability variations on the surface. Samples with different ratios of calcium carbonate/kaolin clay pigment showed an increased porosity and an increase in print density with increasing amount of kaolin in the coating layer.
{"title":"Flexographic ink-coating interactions : Effects of latex variations in coating layers","authors":"E. Bohlin, C. Johansson, M. Lestelius","doi":"10.32964/TJ15.4.253","DOIUrl":"https://doi.org/10.32964/TJ15.4.253","url":null,"abstract":"The aim of the work described in this thesis is to characterize the structure of coatings and prints, and to validate models for the optical response and interaction of ink and coating based on optical measurements of physical samples. It is the interactions between the printing ink and the porous structure of the coating layers that are subject to investigation. Experiments have been employed to relate the physical conditions in a flexographic printing nip to the ink setting and the resulting optical response.By comparing simulated and measured results, it was shown that modifications of the surface properties account for the brightness decrease when substrates are calendered. Light scattering simulations, taking into account the surface micro-roughness and the increase in the effective refractive index, showed that surface modifications accounted for most of the observed brightness decrease, whereas the bulk light scattering and light absorption coefficients were not affected by calendering.Ink penetration affects the print density, mottling and dot gain. Results show that ink distribution is strongly affected by surface roughness, differences in pore size and pore size distribution. For samples having different latex amounts and different latex particle sizes, a higher print force did not increase the depth of penetrated ink to any great extent, but rather allowed the wetting to act more efficiently with a more evenly distributed ink film, a higher print density and fewer uncovered areas as a result. Uncovered areas could be linked both to local roughness variations and to local wettability variations on the surface. Samples with different ratios of calcium carbonate/kaolin clay pigment showed an increased porosity and an increase in print density with increasing amount of kaolin in the coating layer.","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69472475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carolyn M. Wilke, N. Andersson, R. Fleet, Akhlesh K. Mathur, U. Germgard
While carryover of dissolved lignin between stages in the pulp mill fiber line is a well-known problem, it is still typically seen only as a minor disturbance factor or bias in the control of oxygen (O-2) delignification and bleaching stages. The present study, however, reveals that it plays a larger role than anticipated, and that it should be properly analyzed in order to correctly control the process stages. This is especially important for the O-2 and D-0 stages as the lignin content is still high in these positions. The results of the study show that dissolved lignin carried over between stages may have a significant impact on the bleaching chemical consumption and, indirectly, on the pulp quality. Mill investigations have shown very large variations in the dissolved lignin content in the pulp before the oxygen delignification stage and before the D-0 stage that have significantly influenced the bleaching chemical demand and, subsequently, the degree of delignification. In order to develop a better understanding of the mechanisms of the dissolved lignin's reactions, laboratory O-2 and D-0 experiments with controlled levels of dissolved lignin were conducted. It was anticipated that a better feedforward control could be achieved using an online dissolved lignin measurement, and results from mill trials are presented. Chlorine dioxide laboratory experiments using different levels of carryover (i.e., different dissolved lignin contents) were conducted. It was concluded that the filtrate kappa number provides a relevant measure of the bleach demand due to the dissolved lignin and that, subsequently, the combined fiber and filtrate kappa number provides an appropriate measure for optimum feedforward control of the stages. Mill results support these findings, which show that the chemical consumption is reduced significantly using the total kappa number. The post-D or post-DE kappa number feedback control can most probably be eliminated by using this technology.
{"title":"Impact of dissolved lignin in oxygen delignification and chlorine dioxide stages","authors":"Carolyn M. Wilke, N. Andersson, R. Fleet, Akhlesh K. Mathur, U. Germgard","doi":"10.32964/TJ15.3.167","DOIUrl":"https://doi.org/10.32964/TJ15.3.167","url":null,"abstract":"While carryover of dissolved lignin between stages in the pulp mill fiber line is a well-known problem, it is still typically seen only as a minor disturbance factor or bias in the control of oxygen (O-2) delignification and bleaching stages. The present study, however, reveals that it plays a larger role than anticipated, and that it should be properly analyzed in order to correctly control the process stages. This is especially important for the O-2 and D-0 stages as the lignin content is still high in these positions. The results of the study show that dissolved lignin carried over between stages may have a significant impact on the bleaching chemical consumption and, indirectly, on the pulp quality. Mill investigations have shown very large variations in the dissolved lignin content in the pulp before the oxygen delignification stage and before the D-0 stage that have significantly influenced the bleaching chemical demand and, subsequently, the degree of delignification. In order to develop a better understanding of the mechanisms of the dissolved lignin's reactions, laboratory O-2 and D-0 experiments with controlled levels of dissolved lignin were conducted. It was anticipated that a better feedforward control could be achieved using an online dissolved lignin measurement, and results from mill trials are presented. Chlorine dioxide laboratory experiments using different levels of carryover (i.e., different dissolved lignin contents) were conducted. It was concluded that the filtrate kappa number provides a relevant measure of the bleach demand due to the dissolved lignin and that, subsequently, the combined fiber and filtrate kappa number provides an appropriate measure for optimum feedforward control of the stages. Mill results support these findings, which show that the chemical consumption is reduced significantly using the total kappa number. The post-D or post-DE kappa number feedback control can most probably be eliminated by using this technology.","PeriodicalId":22255,"journal":{"name":"Tappi Journal","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2016-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69472463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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