Mechanical Properties Of Paper Research Articles

Low-fibrillated bacterial cellulose nanofibers as a sustainable additive to enhance recycled paper quality

Bacterial cellulose is a biological macromolecule synthesized by bacteria of high purity and crystallinity. Bacterial cellulose nanofibers (BCNF) have been produced by soft homogenization and added to a recycled pulp to improve its quality. The benefits of BCNF on mechanical, physical and optical paper properties have been quantified and the retention mechanism of the BCNF in the paper network has been proposed. The use of BC to improve paper strength is usually limited by the decrease of tear index. The novelty of this work is that these two effects are decoupled by the addition of BCNF of low fibrillation (35.2%). In this way, some BCNF clusters are produced together with the individual nanofibers. Thus, with the addition of 3% BCNF, tensile and tear indexes as well as strain at break were improved by 11.1, 7.6, and 66.8%, respectively. Furthermore, the clusters were retained in the fiber network not only by hydrogen bonding, but also by physical retention within the gaps. Therefore, the addition of BCNF not only increases the mechanical properties of paper but also makes the handsheets more flexible and facilitates filler retention.

The effect of oxyalkylation and application of polymer dispersions on the thermoformability and extensibility of paper

Wood fiber-based packaging materials, as renewable materials, have growing market potential due to their sustainability. A new breakthrough in cellulose-based packaging requires some improvement in the mechanical properties of paper. Bleached softwood kraft pulp was mechanically treated, in two stages, using high- and low-consistency refining, sequentially. Chemical treatment of pulp using the oxyalkylation method was applied to modify a portion of fiber material, especially the fiber surface, and its compatibility with polymer dispersions including one carbohydrate polymer. The results showed that the compatibility of the cellulosic fibers with some polymers could be improved with oxyalkylation. By adjusting mechanical and chemical treatments, and the thermoforming conditions, the formability of paper was improved, but simultaneously the strength and stiffness decreased. The results suggest that the formability of the paper is not a direct function of the extensibility of the applied polymer, but also depends on the fiber network structure and surface energy.

Colloidal Starch and Cellulose Nanocrystals Unite To Improve the Mechanical Properties of Paper: From Enhanced Coatings to Reinforced Nanocomposites

Emerging paper-based technologies encompassing lab-on-a-chip platforms, microfluidics, sensors, actuators, flexible electronics, and energy-storage devices, such as batteries, demand mechanically robust substrates. Current gold standards for paper and paper board reinforcement rely on petroleum-based binders and coatings, such as latex beads cured with melamine formaldehyde and urea formaldehyde resins, which have raised the red flag because of their environmental footprints. Here, we introduce an all-green reinforcing nanocomposite based on the ammonium zirconium carbonate (AZC)-mediated synergistic crosslinking of starch nanoparticles (biolatex) and a newly emerged type of nanocelluloses named anionic hairy cellulose nanocrystals. AZC, an environmentally friendly and cost-effective crosslinker, reacts with the hydroxyl groups of starch and cellulose nanocrystals, while the carboxylic acid groups of hairy nanocelluloses maintain the solution viscosity low, favoring industrial transportation, which may no...

APPLICATION OF CHEMICAL ADDITIVES FOR RESOURCE CONSERVATION PRODUCTION OF PAPER AND CARDBOARD

The aim of the study is to evaluate the interaction of amphoteric polymer resins with cellulose fibers at the molecular level.The interaction of amphoteric polymer resins with cellulose fragments was determined by standard 1H NMR and 13C spectroscopy techniques.To study the interaction of amphoteric polymeric resins with cellulose at the molecular level, imitation modeling has been carried out in the work. The essence of the simulation is the replacement of cellulose fibers with substances that are close to the functional purpose of cellulose. Such substances include glucose, sucrose, starch and ethylene glycol, which dissolve in water. It is established that in the presence of a large amount of water in the APS – waste paper system, intermolecular and interfluid hydrogen bonds are formed, and upon reaching a critical amount of water in the system, new covalent ether-type bonds are formed between the functional groups of the components as model systems and amphoteric polymeric systems resin - cellulose and this indicates the possibility of increasing the physical and mechanical properties of paper and paperboard from secondary raw materials.The results show that simulation simulation of structural and functional transformations in complex systems, including the cellulose-APS system, confirms the presence in them of processes that occur during the interaction of amphoteric polymeric resins with hydroxyl groups of cellulose fibers

Aging characterization of electrical insulation papers impregnated with synthetic ester and mineral oil: Correlations between mechanical properties, depolymerization and some chemical markers

This article presents a comparative study of two types of transformer solid insulation: standard Kraft and thermally upgraded Kraft papers. The paper samples were impregnated with two different fluids, namely a synthetic dielectric ester fluid, Midel 7131, and a synthesized mineral oil, Luminol Tri. The impregnated papers were submitted to, accelerated aging at 150°C, temperature higher than the temperatures found inside transformers, for extended periods. The results show that for the first hours of aging, the cellulose depolymerization was similar for all the four studied cases. At a specific point, the paper samples aged in the ester fluid exhibited a lower depolymerization exceeding the 8000 hours of aging without reaching the levelling-off degree of polymerization (LODP). A similar trend was observed through the decrease of mechanical properties of papers in the ester-based oil. However, the difference in performance of both fluids was amplified due to the temperature used; at lower temperatures the difference should be smaller. Additionally, a relationship between the degree of polymerization and the mechanical properties accessed by the tensile testing was obtained regardless of the type of paper or oil. The total acidity in the ester fluid was higher than in mineral oil. Methanol, a chemical marker that is closely linked to the rupture of 1,4-ß-glycosidic bonds of cellulose, showed a partial sensitivity to the cellulose aging in the ester fluid. Furan (C <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> H <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf> O) content was monitored during the aging and its concentration was found to be sensitive to the depolymerization along with the decrease in the mechanical properties of cellulose papers regardless of the type of paper. More importantly, its concentration was found to be dependent on the type of oil. More investigations are needed to further confirm the importance of furan as an indirect indicator of the mechanical performance along with its correlation with the depolymerization of paper aged in ester fluids.

Effect of Laccase-Mediated Biopolymer Grafting on Kraft Pulp Fibers for Enhancing Paper's Mechanical Properties.

High-resistance paper was manufactured by laccase-grafting of carboxymethyl cellulose (CMC) and chitosan (CPX) on Kraft pulp fiber. The reaction was mediated in the presence of laccase by one of the following polyphenols in the presence of air: gallic acid (GA), vanillic acid (VA) and catechol (1,2–DHB). Enzyme was added at constant loading (24 kg ton−1), 1% pulp consistency, 0.005% CMC, pH = 6.3 ± 0.5 and 2 mM of mediator. CPX content was assessed at two levels (0% and 0.005%). Treated pulps were analyzed by different mechanical tests (ring crush, mullen, corrugating medium test (CMT) flat crush of corrugating medium test and tension). An improvement in these parameters was obtained by biopolymer coupling and selected mediator. When using GA, three parameters increased more than 40%, while ring crush increased 120%. For the case of VA, properties were enhanced from 74% to 88% when CPX was added. For 1,2–DHB, there was not found a statistically significant difference between the results in the presence of CPX. Scanning electron microscopy, confocal microscopy, FTIR and 13C NMR were used in all papers in order to evaluate grafting. Hence, it was possible to correlate polymerization with an improvement of paper’s mechanical properties.

Mechanical and chemical dispersion of nanocelluloses to improve their reinforcing effect on recycled paper

The use of nanocelluloses as strength-enhancing additives in papermaking is widely known since both cellulose nanofibers (CNF) and nanocrystals (CNC) present similar composition than paper but their exceptional properties in the nanometer scale confers a paper quality enhancement. However, some agglomeration problems in CNF and CNC through hydrogen bonding cause a lower improvement of mechanical properties of paper. Therefore, a better dispersion of both nanocelluloses can maximize their effect on paper properties, thus reducing the needed dose to get the same increment in tensile strength and then reducing material costs. To ease the implementation of these nanocelluloses in the production process of recycled paper, typically used operations of these industries have been used. Among them, those devoted to improve the homogeneous mixture of nanocellulose in the pulp suspension have been assessed. Firstly, pulping conditions were studied, including pulping time, temperature and need for soaking as variables. Secondly, some dispersing agents used in papermaking were considered, studying the effect of different types and doses. The highest tensile strength of paper was achieved by applying long pulping times (60 min), getting increments up to 30% with the use of soaking and polyacrylamide as retention system. However, with the use of a low dose of a dispersing agent (0.003%), tensile index can be still increased up to 20.6% avoiding these long times. This study can be of great interest of those researchers trying to implement the use of nanocelluloses as strength additive in papermaking.

Recycled fibers for fluting production: The role of lignocellulosic micro/nanofibers of banana leaves

Recycling is becoming one of the main activities of the papermaking industry to palliate the consumption of natural resources. However, with the recycling process, the fibers experience structural damages due to the hornification phenomena and the mechanical refining. The present work aims to compare the effect of mechanical refining during recycling cycles, to recover the original mechanical properties of paper with the incorporation of lignocellulosic micro/nanofibers (LCMNF) from banana leaf residue. For that, industrial fluting paper was submitted to a recycling cycle and the effect of the increasing intensity of PFI-refining was compared versus the incorporation of LCMNF additions ranging from 1.5 to 4.5 wt%. In addition, with the objective of demonstrating that the proposed process could be plausible at a large scale, process water with high conductivity and charge density was used for comparison with tap water, usually used at laboratory scale. Results showed that the incorporation of 1.5 wt% of LCMNF was enough to recover the original properties of fluting paper (a breaking length value greater than 3443 m) with a low impact in pulp drainability (54 ºSR). At the same time, no structural damages were caused to the fibrous compounds, implying that the life span of paper products can be successfully increased. Higher dosages lead to papers with significantly improved mechanical properties, opening the opportunity to adopt environmental friendly strategies such as decreasing basis weight or, on the other hand, to reach new market niches by maintaining the basis weight.

The effects of different types of wet-end added microfibrillated celluloses on the properties of paper made from bleached kraft pulp

Research has been undertaken to compare the effects of different types of microfibrillated cellulose (MFC) on the mechanical properties of paper. Three types of MFC were produced: Enzyme MFC (low a ...

Bioindustrial Innovation Canada: A Sustainable Chemistry Alliance Creating Jobs and Economic Value Sustainably for Canada

Industrial BiotechnologyVol. 13, No. 4 Catalyzing InnovationBioindustrial Innovation Canada: A Sustainable Chemistry Alliance Creating Jobs and Economic Value Sustainably for CanadaJulia Struyf, A.J. Marshall, Peter Van Ballegooie, Anne Waddell, Debby Harris, and John BisselJulia StruyfBioindustrial Innovation Canada, Sarnia, OntarioSearch for more papers by this author, A.J. MarshallBioindustrial Innovation Canada, Sarnia, OntarioSearch for more papers by this author, Peter Van BallegooieEcoSynthetix, Burlington, OntarioSearch for more papers by this author, Anne WaddellBioAmber, Sarnia, OntarioSearch for more papers by this author, Debby HarrisS2G BioChem, Vancouver, British ColumbiaSearch for more papers by this author, and John BisselOrigin Materials, West Sacramento, CaliforniaSearch for more papers by this authorPublished Online:1 Aug 2017https://doi.org/10.1089/ind.2017.29090.jstAboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View article"Bioindustrial Innovation Canada: A Sustainable Chemistry Alliance Creating Jobs and Economic Value Sustainably for Canada." Industrial Biotechnology, 13(4), pp. 182–183FiguresReferencesRelatedDetailsCited byColloidal Starch and Cellulose Nanocrystals Unite To Improve the Mechanical Properties of Paper: From Enhanced Coatings to Reinforced Nanocomposites28 February 2018 | ACS Applied Nano Materials, Vol. 1, No. 4 Volume 13Issue 4Aug 2017 InformationCopyright 2017, Mary Ann Liebert, Inc.To cite this article:Julia Struyf, A.J. Marshall, Peter Van Ballegooie, Anne Waddell, Debby Harris, and John Bissel.Bioindustrial Innovation Canada: A Sustainable Chemistry Alliance Creating Jobs and Economic Value Sustainably for Canada.Industrial Biotechnology.Aug 2017.182-183.http://doi.org/10.1089/ind.2017.29090.jstPublished in Volume: 13 Issue 4: August 1, 2017PDF download

A facile sodium alginate-based approach to improve the mechanical properties of recycled fibers

The application of recycled fibers is steadily increasing in various paper products recently. It is necessary to improve the mechanical properties of paper products made from these fibers. An eco-friendly polymeric additive, sodium alginate (SA), was prepared from waste seaweeds and developed as functional additives. The properties of SA were characterized by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravity analysis, gel permeation chromatography, and compared with the commercial SA. Coupled with polyamideamine-epichlorohydrin (PAE), the extracted SA was used to enhance the mechanical properties of paper from recycled fibers. The surface and cross-section morphology of the paper were measured by scanning electron microscopy and discussed. Compared with the single addition of PAE, the SA-PAE binary system significantly improved the mechanical properties of paper sheets.

Impact of Physical Deformation on Electrical Performance of Paper-Based Sensors

We report on investigation of the mechanical properties of paper electronics (printed and made out of paper). One key objective of such paper electronics is to achieve ultraflexibility. Therefore, it is important to understand electrical functionality and reliability of paper electronics under various physical (mechanical) deformations. Here, we show the general mechanical properties of the cellulose paper used and its electrical behavior under applied strain, tackling the main effects that need to be identified when building paper-based systems, from product performance and stability perspective. An overview of the stress–strain behavior of silver ink on paper is discussed, and then, we tackle a more specific analysis of the performance variations of paper sensors made with recyclable household materials when exposed to various mechanical conditions of tensile and compressive bending. This paper is important for developing stable wearable sensors for incorporation into Internet of Everything applications.

Innovative technology for making improved paper from the poorest fibers

The trademarked Papermorphosis technology, consisting of two novel units for separately increasing cross direction (CD) and machine direction (MD) elongation over purely mechanical processes, has been successfully tested on recycling fiber, reaching high elongation values in each direction of over 15% in CD or 20% in MD. Increase of elongation has also had a positive influence on the relative tensile energy absorption (TEA) values in CD and MD. It is well known that mechanical properties in paper basically depend on fiber choice, headbox properties, and refining. With the novel system, elongations in cross direction (CD) and machine direction (MD) can be individually customized, even in paper grades with lower strength deriving from recycled fiber. Customizing elongations also has the effect of improving or better balancing TEA values in both directions. The aim is to improve existing recycling papers and to broaden the use of recycling fiber with respect to the past.

Surface modification of graphene oxide sheets on magnetic particles for magnetic paper

Magnetic paper manufactures are nowadays widely used in information storage, electromagnetic shielding and security industry for its outstanding performances. In this article, Tb-doped germanium borosilicate glass was prepared by melt quenching technique and they were used as magnetic sources of magnetic paper to loading into the bamboo fibers. Magnetic paper has been successfully produced by adding inorganic magnetic particles modified by different concentrations of graphene oxide (GO) solution. The samples were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy, Superconducting Quantum Interferometer Device (SQUID) and Scanning Electron Microscope (SEM). The results shown that the structure of magnetic particle are made from [BO3], [BO4], [A1O6], [SiO4] and [GeO4]. GO sheets had been successfully immobilized on magnetic particles (MPs) surface via electrostatic interaction. SQUID indicated that the magnetic particles and papers were paramagnetic materials. SEM images clearly shown that the MPs loaded into the lumen of bamboo fibers and the interstitial of fibers. Bridge-fibers that connecting other cellulose fibers and MPs by hydrogen bonds were formed in the network of paper due to the functional groups on surface of magnetic particles. The mechanical properties of papers increased with the increment of GO concentration, which is correlated with the hydrogen-bonding that forming by bridge-fibers and other cellulose fibers in network of paper.

Passivation of pressure sensitive adhesive stickies by addition of acrylic fibers to OCC pulp before papermaking

This study investigated the addition of acrylic fiber to old corrugated container (OCC) pulp as a possible means of overcoming adverse effects of water-based pressure sensitive adhesives during manufacture of paper or paperboard. Such adhesives can constitute a main source of stickies, which hurt the efficiency of the papermaking process and make tacky spots in the product. The highest amount of acrylic fiber added to recycled pulps generally resulted in a 77% reduction in accepted pulp microstickies. The addition of acrylic fibers also increased pulp freeness, tear index, burst strength, and breaking length, though there was a reduction in screen yield. Hence, in addition to controlling the adverse effects of stickies, the addition of acrylic fibers resulted in the improvement of the mechanical properties of paper compared with a control sample.

Preparation and characterization of corn starch–calcium carbonate hybrid pigments

This article presents a novel method for integrating native corn starch and calcium carbonate (CaCO3) into a hybrid pigment, which can be applied in papermaking to increase the amount of starch in paper and improve sheet bonding without impairing dewatering. Starch was first thermally treated to partially gelatinize and swell the granules. The aim of the treatment was to change the surface properties of starch and thus to improve the interaction with CaCO3 particles. CaCO3 shell was precipitated around the swollen granules and the encapsulated starch was then cooked to achieve complete gelatinization. When the granules were cooked, the starch became active for bonding, but its solubility was very limited due to the encapsulation. Particle size measurement and scanning electron microscopy were used to analyze the sample properties during the preparation. The hybrid pigment was added to paper sheets and its effect on the paper properties was examined. Starch was shown to be effectively bound to the pigment structure. The hybrid pigment allowed a large amount of native corn starch to be added to paper without interfering with the papermaking process. Furthermore, it gave excellent mechanical paper properties.

PVB/sepiolite nanocomposites as reinforcement agents for paper

In order to improve the mechanical properties of paper, 1, 3 and 5 wt.% of sepiolite were dispersed in a poly(vinyl butyral) (PVB) matrix and coated onto the surface of schrenz (110 g m-2). Deagglomerated sepiolite nanofibers in PVB matrix on paper surface were observed by scanning electronic microscopy. The glass transition temperature of schrenz with PVB/sepiolite coatings was not changed with increasing content of sepiolite. Two different methods were used to evaluate the mechanical properties of the paper sample reinforced with PVB/sepiolite nanocomposites: tensile testing and nanoindentation. The values of breaking force and tensile energy absorption of the reinforced paper samples obtained by tensile testing were increased by up 10 %. The values of the reduced elastic modulus and hardness obtained by nanoindentation were increased by up to 78 %. The best improvement of the mechanical properties was shown by the paper sample coated with PVB/3 wt.% sepiolite nanocomposite.

Relationships between methanol marker and mechanical performance of electrical insulation papers for power transformers under accelerated thermal aging

The mechanical performance of two commercial papers used as solid insulation in power transformers, namely standard Kraft and a thermally upgraded Kraft paper, were studied during accelerated aging in Luminol oil at 170 °C. The results show a relationship between the degree of polymerization and the mechanical properties measured by tensile testing. A linear relationship was found between the mechanical properties of paper, the tensile index (Tidx), and the concentration of methanol present in the oil. The methanol chemical marker has been proven to be an accurate assessment tool for the aging of cellulosic paper. The results show a promising tool for correlating the methanol concentration in oil, as an indirect indicator, with the mechanical performance of the paper. This approach can be used to monitor the real state of the cellulose chains in the power transformer insulation paper.

Physical properties of cellulosic materials related to moisture changes

Moisture affects the mechanical properties of paper to a high degree. Moreover, the creep properties of paper may be highly affected while the relative humidity is changing, exhibiting mechano-sorptive creep. The reasons for the great sensitivity to moisture changes of papers are not fully explained. In this study, thin papers were examined during sorption processes and the moisture content within the paper, paper length and dynamic elastic modulus during RH changes were measured. It is demonstrated that the dimensional changes of the paper exactly reflected the changes in moisture content within the sample. During both absorption and desorption, the elastic modulus changed so that it was lower than the equilibrium value corresponding to its moisture content. This was especially evident during absorption where the modulus dropped below the equilibrium value at the end RH, i.e. the value was approached from below. The modulus drop was highly related to RH changes made at higher RH and could possibly be related to the softening of carbohydrates.

Use of bacterial cellulose in degraded paper restoration. Part I: application on model papers

Preservation of documentary heritage is one of the biggest challenges facing paper conservators today. The singular properties of bacterial cellulose (BC) lead us to propose to reinforce paper with BC sheets. In the first part of this study, the reinforcing capability of BC was tested on model papers of well-known fiber composition. The aim of the present study was to verify the suitability of rebuilding degraded old papers with BC. The degraded papers were characterized before and after the reinforcement. In addition, lined samples were characterized before and after an aging process in order to study the stability in time. The same methodology was used with Japanese paper (JP), a material commonly used by paper conservators, in order to compare both materials as reinforcement. Mechanical properties of paper lined with BC are as good as those obtained with JP. Papers lined with BC have more marked modifications on their optical properties than those restored with JP. Nevertheless, letters in books lined with BC are more legible. Moreover, only the papers restored with BC show high changes in porosity. The aging process leads to a slight decrement in burst index. Changes on tear index and optical properties with the aging process depend on the paper to be restored. This study suggests that BC improves deteriorated paper quality, without altering the information contained therein, and that this improvement is maintained over time. Hence, BC is a promising alternative material for the restoration of paper.