Mechanical Properties Of Paper Research Articles

Facile fabrication of hydrophobic paper by HDTMS modified chitin nanocrystals coating for food packaging

Paper is an inherent hydrophilic material due to the hydroxyl groups contained in cellulose, which limits its applications in packaging materials. This study proposed a simple one-step method for preparing hydrophobic paper by introduction of chitin nanocrystals (ChNCs) and hexadecyltrimethoxysilane (HDTMS). The surface chemistry and morphology of coated paper were studied in detail. The 2%ChNCs/HDTMS coated paper was highly hydrophobic with a water contact angle greater than 130°, mainly due to the low surface energy provided by HDTMS. Compared with uncoated paper, the hydrophobic paper's tensile strength and water vapor barrier are significantly improved due to the addition of ChNCs. Meanwhile, the hydrophobic paper shows excellent environmental tolerance and mechanical stability. The survival rate of L929 cells on the modified paper was more than 80% by CCK-8 assay, which proved that the nanocoating was safe. In addition, the obtained hydrophobic coated paper can hold water, cola, green tea, milk, coffee, and orange juice for a long time and can be used as a straw to absorb liquid. This work prepared high-performance and green hydrophobic paper, which exhibits wide applications in food packaging. • Hydrophobic paper coated with ChNCs/HDTMS was fabricated by one-step method. • ChNCs/HDTMS enhanced water vapor barrier and mechanical properties of paper. • The coated paper exhibited excellent environmental tolerance. • Hydrophobic paper showed antibacterial adhesion and satisfied biocompatibility. • The hydrophobic paper can be made into straw and paper cup.

Removal Ability of Bacillus licheniformis on Waxy Cuticle on Wheat Straw Surface

The outermost surface of wheat straw (WS) is covered with hydrophobic lipophilic extracts and silica, which affects follow-up processes such as impregnation pretreatment of pulping and papermaking. In this study, a strain named Bacillus licheniformis (B. licheniformis) was screened from the black liquor of papermaking, which was used to explore the effect of its treatment on the waxy cuticle of WS. Scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) showed that the B. licheniformis had a certain destructive effect on the outer surface of WS and the content of Si on the outer surface decreased by 80%. The results of FTIR and X-ray photoelectron spectroscopy (XPS) displayed that the wax composition on the outer surface of WS decreased and the fiber structure inside appeared. The mechanical properties of paper demonstrated that the treated WS is still feasible in this field and the content of Si in the black liquor is reduced by 33%. Therefore, the WS treated by B. licheniformis can destroy the waxy cuticle on its outer surface and improve the wettability of WS. It provides a new idea to alleviate the “Si interference” problem of alkali recovery in WS traditional pulping and papermaking.

Properties and application of kraft pulp prepared from waste bamboo powder

As a by-product of bamboo processing, bamboo powder is incinerated or buried due to its ineffective utilization, which contributes to pollution. The large amount of waste bamboo powder generated during the processing of bamboo products cannot be effectively utilized. Meanwhile, multiple recycling leads to the loss of fiber quality of corrugated cardboard (OCC) pulp, reducing the mechanical properties of paper. In an effort to obtain high value from waste bamboo powder, this study pulped it using the kraft process. Scanning electron microscope (SEM) observations showed that the surface of bamboo fiber had more cracks, which made bamboo fiber have better air permeability. The permeability of bamboo paper was 146% that of the OCC. X-ray diffraction (XRD) analysis showed that the crystallinity of bamboo pulp was 133% that of the OCC pulp. The results of physical testing of paper showed that the tensile strength of bamboo paper was 116% that of the OCC. The tear strength of bamboo paper was 61.7% that of the OCC, and the bursting strength of bamboo paper was 59.1% that of the OCC. Based on the above results, bamboo powder can be used as raw material for making OCC pulp.

Dilute Acid Pretreatment of Wheat Stubble Agro-Residues to Eliminate Non-Process Components Meant for Papermaking and its Impact on Mechanical Strength Properties of Paper Products

Wheat stubble agro-residues material contains lingo-cellulose with high level of extractives and metal ions, which may be able to instigate some harmful impacts on the papermaking process. Pretreatment of stubble on the removal of metal ions and extractive, its impact on the content of chemical constituents like holocelluose, lignin, silica, the pulping yield as well as the mechanical properties of paper were examined in the laboratory. Acid pretreatment significantly reduced the content of the metal ions with about more than 50%. The conditions for acid pretreatment of the material were optimized to pH-2 at 5% consistency for 1 hour retention time with more benefits in extractives and metal ions removal and less impact on cellulose degradation. The demand of active alkali charge during pulp making was observed to be about 3% lower for the pretreated material as compared to the untreated one. Despite of chemical conservation, a higher pulping yield of about 6-7% was also observed in case of acid pretreated materials. Improved thickness, more crystalline and a high degree of polymerization of cellulose fibre were noticed due to acid pretreatment and the pulp obtained from acid pretreated material showed improved mechanical strength properties (tensile, tear, burst strength etc.). The study revealed that pretreatment of agro-residue material with dilute acid (optimized conditions) could be used to remove the non-process component and make it suitable for utilization in papermaking process with improved mechanical properties in the paper products.

Preparation of superhydrophobic conductive CNT/PDMS film on paper by foam spraying method

Paper-based materials are widely used in agriculture, industry and daily life because of their biodegradability, sustainability, biocompatibility and low cost. However, due to the hydrophilic nature of plant fibers in paper-based materials, the mechanical properties of paper will be reduced after absorbing water, thus limiting its application field. In this paper, carbon nanotubes/polydimethylsiloxane (CNT/PDMS) films with hydrophobicity and conductivity were prepared on filter paper by foam spraying method. Firstly, CNT and PDMS were added into water and stirred vigorously, and CNT/PDMS foam homogenate was prepared by foaming agent and stabilizer. Then, the homogenate was sprayed on the filter paper with a spray gun, and the multilevel rough structure was prepared on the paper. The results showed that the contact angle of the sample surface is greater than 150° when the spraying amount is 0.4-CNT, 0.6-CNT and 0.8-CNT, and the contact angle of 0.6-CNT is 156.33°, which is the largest. The drops on the surface of the sprayed sample have good bounce and self-cleaning performances. In addition, benefiting from the excellent conductivity of CNT, the particles composed of CNT and PDMS contact each other on the surface of the sample, forming a conductive network. The aforementioned properties will broaden the application scenarios of paper-based superhydrophobic materials.

A facile method to prepare cellulose fiber-based food packaging papers with improved mechanical strength, enhanced barrier, and antibacterial properties

Cellulose fiber-based food packaging papers with enhanced barrier and antibacterial properties were successfully fabricated by sequential deposition multilayers consisting of chitosan (CS) and carboxymethyl cellulose (CMC) on paper surface. The formation of CS/CMC multilayers on paper surface was systematically characterized. The CS/CMC multilayers effectively improved not only the barrier properties of papers against grease, oil, water, air and water vapor, but also the mechanical properties of papers. Moreover, the CS/CMC multilayer-modified papers showed improved antibacterial activities against E. coli and S. aureus. A (CS/CMC)5 multilayer-modified paper exhibited the strongest antibacterial activity with growth inhibition rate of 95.8% against E. coli and 98.9% against S. aureus. No obvious cytotoxicity was detected for the obtained modified paper. Therefore, in consideration of its mechanical, barrier, antibacterial and safe performances, it is expected that the as-prepared cellulose fiber-based paper can be used as a promising material for food packaging.

Pulping Yield and Mechanical Properties of Unbeaten Bamboo Paper

One way to minimize emissions of greenhouse gases that contribute to climate change is to reduce the use of wood as the main material for pulp and paper production. Therefore, non-woody plants such as bamboo can be alternatives as raw materials for pulp and paper. This study aims to determine the effect of the different bamboo species and age on the bamboo pulping yield and bamboo mechanical paper properties. Bambusa vulgaris, Gigantochloa levis, and Gigantochloa scortechinii bamboo species or locally known as Aur, Beting, and Semantan bamboo at the age of 1, 3, and 5-year old, were pulped using Soda-Anthraquinone (AQ) pulping. No beating process was conducted to all the papermaking processes to evaluate the basic mechanical properties of the bamboo paper. Pulping yield ranged from 35.7 to 51.7% at different bamboo species and age, with the pulping conditions at 20% of NaOH, 170ºC pulping temperature, 90 min time to reach pulping temperature and 90 min time at pulping temperature, 1:6 of bamboo to liquor ratio and 0.1% of AQ based on bamboo oven-dried weight. The paper was made according to TAPPI Standard T205 sp- 95. The paper mechanical properties for burst index, tear index, tensile index, and folding endurance ranged from 1.32 to 2.36 kPa.m2/g, 7.48 to 14.9 Nm2/g, 16.02 to 29.68 Nm/g, and 2 to 28 double folds, respectively, at different bamboo species and age. It was found that Beting bamboo has the potential to be a viable raw material for pulp and paper products as it shows the highest mechanical properties compared to Aur and Semantan.

A study on effect of modified calcite on filler retention and mechanical properties of fluting papers

In this study, the use of modified calcite as a filler in fluting paper production was investigated and its effect on retention and some mechanical properties of papers was investigated. Ground calcium carbonate (GCC/calcite) and cationic starch were used for modification. Filler modification with alum effect of CPAM resulted in starch-calcite encapsulation. Produced modified calcite (MC) was used in fluting paper production at certain dosages. Simultaneously, paper was made with unmodified calcite (UC), and the effects of modified calcite on paper properties and filler retention were studied. According to the study's findings, the use of 10% MC improved filler retention and provided approximately 23% more retention than the use of 10% UC. In addition, mechanical properties and air permeability values of MC-filled papers were higher than UC-filled papers. With the use of MC in fluting papers, better filler retention was achieved, while the reduction in mechanical properties caused by the addition of filler in general can be minimized. Besides, impurities in white water can be minimized by reducing the filler dosage given during paper production.

Preparation, structure and application of styrene-acrylic emulsion/modified ammonium polyphosphate in flame retardant air filter paper

The filter paper of automobile engine air filter is easy to temper and causes combustion. Flame retardant is usually added to the reinforced resin styrene-acrylic emulsion (SAE) to improve the flame-retardant performance of the air filter paper. Ammonium polyphosphate (APP) was used as material in this research, and multi-layer coated APP was prepared by microcapsule coating. A layer of nano-scale SiO2 was coated and then introduced organosiloxane structure of the allyl polyoxypropylene ether side chain and boron. The chemical groups and structural composition were determined by Fourier transform infrared spectroscopy. TGA characterized the modified particles' high-temperature stability. By scanning electron microscopy and TEM, the morphologies of modified particles were analyzed to reveal the evolution of modified APP in SAE. Finally, nanoparticles with core-shell structures were formed. Applying the blended resin to the air filter paper, the flame-retardant performance was greatly improved. Total heat release (THR), heat release rate (HRR), peak heat release rate (pkHRR), mass loss rate (MLR), and effective heat of combustion (EHC) were reduced, respectively, by 30.8%, 30.7%, 42.0%, 16.7%, and 14.4%. The time to ignition (TTI) was doubled, so the fire spread could be effectively suppressed. Meanwhile, nano latex particles were attached to the interwoven fibers points and formed a “sea-island structure,” which significantly improved the paper’s mechanical properties, with bursting strength, tensile strength, stiffness, fracture work, and elongation increased by 18.60%, 5.72%, 10.64%, 17.00%, and 81.80%, respectively. It solved the problem that the inorganic flame-retardant particles often lead to the deterioration of the mechanical properties of paper.

Application of carboxymethyl cellulose-acrylate-OVPSS graft copolymer emulsion in paper reinforcement and protection

Abstract Paper cultural relics are both precious, inheritable and fragile. However, with the passage of time, paper will also be affected by a variety of factors, and will appear mildew, yellow, brittle, or even completely damaged. In order to protect the cultural relics, extend lifespan paper, CMC-acrylate-OVPOSS graft copolymerization emulsion was synthesized by using carboxymethyl cellulose (CMC) as substrate, methyl methacrylate (MMA), butyl acrylate (BA), glycidyl methacrylate (GMA), hydroxyethyl methacrylate (HEMA), octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) as graft copolymer. The CMC-acrylate-OVPOSS emulsion was coated on the surface of the paper to test its protective effect on the paper. The results showed that the mass concentration of 10 % reinforcement solution coated on the paper, mechanical properties of paper were greatly improved, and the gloss and whiteness of paper were slightly changed, the paper also had a certain aging resistance and acid and alkali corrosion resistance. At the same time, the reversibility experiment showed that the reinforcement material had a certain reversibility.

Art Paper for Large Wood Relief Block Printing – A Paper Development Study

Wood relief block printing was developed in China in the seventh century and is used today for many art printing applications. The presented research project describes the development of an art paper product applicable for large wood relief block printing from laboratory scale to large semi commercial production of art paper for printing image sizes of up to 44-inch (1118 mm) by 96-inch (2400 mm) at outdoor steam roller printing events or smaller indoor printing press applications.
 The improvement of the paper properties from laboratory development, small laboratory paper machine and semi commercial paper machine run for the production of the final art paper showed an improvement throughout the process development for the optical and mechanical paper properties and exceeded the set values set by the artist using the art paper.
 The produced art paper with a basis weight of 260 g/m² and a thickness of 171 µm is produced from a mixture of 70% northern bleached hardwood Kraft pulp and 30% northern bleached softwood Kraft pulp.
 The ISO brightness of the art paper off-white (egg-shell) colour was at 63.2% and the ISO color value for L, a, b. at 90.8, 1.1, and 12.6 respectively.
 The art papers surface roughness and porosity as a parameter for ink attachment and penetration is for the top side 2179 ml/min and for the bottom side (wire side) 2326 ml/min, whereas porosity was measured at 1668 ml/min.
 Bending stiffness in machine direction and cross machine direction was measured at 157mN and 70 mN respectively. Burst strength was measured at 2.24 kPA·m²/g.

Novel method for the evaluation of mechanical property of pigment coating layer and its application: Influence of spreading of latex binder on final properties of coating layer

The mechanical properties of paper coating layers are important in various processes and applications. Proper evaluation of the coating layers is essential for improving coating layer design. In this study, a novel method for the evaluation of the mechanical properties of coating layers was developed using a surface and interfacial characterizing analysis system (SAICAS) instrument, which has an important advantage of not requiring any special sample preparation process. Failure analysis results showed that the SAICAS method provided uniform and reproducible sectioning of the coating layer regardless of the layer's mechanical strength, indicating this is suitable for measuring the mechanical properties of coating layers. The influence of the spreading of latex binder on the final properties of the coating layer was examined and its correlations with structural properties were quantitatively analyzed. This was applied to analyze the mechanical, topographical, and optical properties of coating layers. The results showed that the peel strength and gloss were highly correlated with the spreading of latex. The chemical composition of S/B latex also influenced the peel strength of the coating layer. The transitions observed in the length distribution of pigment–binder interfaces greatly influenced the properties of the coating layer, including peel strength, gloss, and light-scattering efficiency.

The effect of green biobased binder on structural, mechanical, liquid absorption and wetting properties of coated papers

Synthetic styrene-butadiene (SB) and styrene-acrylic (SA) latex binders used in paper coating formulations are common and based on unsustainable petroleum sources. Today's papermaking industry turns towards sustainable substitutes that do not compromise quality, and reduce carbon emission, toxic substance release and waste disposal concerns related to fossil fuel sources. In this study, colloidal starch-based latex nanoparticles that do not require cooking were used for pigment coating and coated on the paper surfaces. The effects of these new biobased binders on the structural and mechanical strength properties, liquid absorption, wetting and surface topography of the paper were investigated and compared with the properties of coated paper that SB latex was used as a coating binder. The results demonstrated that the biobased latex decreases the grammage of paper while maintaining an identical thickness relative to the SB latex samples. The porosity, permeability and roughness of biobased latex are found higher than the SB latex. The biobased latex successfully replaced SB latex at 1:1 ratio and enabled an equivalent of bursting, tear, tensile strength and structural properties. Synopsis : A plant-based starch nanoparticle latex is engineered to replace petroleum based synthetic latexes without compromising structural and mechanical paper properties.

Role of cellulose nanofibrils in improving the strength properties of paper: a review

The pursuit for sustainability in the papermaking industry calls for the elimination or reduction of synthetic additives and the exploration of renewable and biodegradable alternatives. Cellulose nanofibrils (CNFs), due to their inherent morphological and biochemical properties, are an excellent alternative to synthetic additives. These properties enable CNFs to improve the mechanical, functional, and barrier properties of different types of paper. The nanosize diameter, micrometre length, semicrystalline structure, high strength, and modulus of CNFs have a direct influence on the mechanical properties of paper, such as tensile index, burst index, Scott index, breaking length, tear index, Z-strength, E-modulus, strain at break, and tensile stiffness. This review details the role played by CNFs as an additive to improve strength properties of paper and the factors affecting the improvement in paper quality when CNFs are added as additives. The paper also includes techno-economic aspects of the process and identifies areas that need further research.

Eucalyptus Pulp Fibers with In-Situ Precipitated Calcium Carbonate – A 12-Inch Laboratory Paper Machine Study

Paper manufacturing on a global scale is a highly competitive market which requires to constantly improve the manufacturing process to be competitive. To decrease production cost paper manufactures, add filler material prior to sheet forming to replace costly wood fiber based raw material.
 This research project investigates the use of in-situ precipitated calcium carbonate produced in the presence of eucalyptus fiber material at a 41.0% filler level prior to beating. The in-situ filler containing eucalyptus fiber suspension was used on a 12’ (304mm) wide Laboratory Fourdrinier Paper Machine together with non-filler containing eucalyptus fiber material, and a commercial precipitated calcium carbonate filler material.
 The manufactured in-situ fiber suspension resulted in a higher ash retention compared to the addition of the powdered commercial PCC filler material. In addition to commercial filler material retention is improved at higher filler addition above 30%.
 The increased ash retention is linked to the increased micro fibrillation fiber material of the in-situ filler-fiber suspension forming neckless like particles on the fibers microfibrils.
 Mechanical paper properties showed an improvement for in-situ precipitated filler material compared to commercial filler material addition.
 Optical properties could be improved in comparison to the eucalyptus fiber without filler addition for in-situ precipitated filler material and a combination of in-situ and commercial filler material.

Effect of bleaching using sodium hydroxide on pulp derived from Sesbania grandiflora

World demand for paper is increasing. Short rotation pulpwood is needed. Sesbania grandiflora also known as Turi, is a fast growing and straight log species. The scholarly information of Turi as pulpwood are still limited. This paper aims to provide information of sodium hydroxide effect on the paper made from pulp derived from Turi. Sodium hydroxide is a common chemical using as part of full stage chemical bleaching in pulp industrial. Kraft pulp that produced using Turi, was bleached with sodium hydroxide at 3%, 6% and 9% based on pulp weight, respectively. Unbleached pulp was served as blank test. The optical and mechanical properties of handsheet paper made from bleached kraft pulp were evaluated according to TAPPI standard. The brightness and opacity of handsheet made from bleached pulp were improved with increasing the concentration of sodium hydroxide. The mechanical properties of handsheet were improved with using 3% sodium hydroxide and gradually decreased after 3% sodium hydroxide. In conclusion, sodium hydroxide is potential to improve optical properties of Turi pulp and improve the mechanical properties of paper made from Turi pulp at certain level. Excessive usage of sodium hydroxide brings adverse effect to mechanical properties of paper made from Turi pulp.

H2O2 bleaching of brown pulp with adsorbed xylan and its modifying effects on the mechanical properties of paper

Xylan is the primary hemicellulose in most hardwood species, especially in birch. Research has highlighted the exploitation of xylans as a strength-enhancing additive to paper due to the current trend for the effective utilization of biomass. In this paper, a new pulping process was proposed, which involved the extraction of xylan prior to pulping, followed by the re-adsorption of the pulp after the final stage in the digester, followed by a suitable bleaching process. The aim of this work was to bleach hardwood kraft pulp (brown pulp) with adsorbed birch xylan via hydrogen peroxide and study the effect of the bleaching parameters on the paper properties. The results showed that the optical properties of paper decreased; however, the mechanical properties increased after the brown pulp adsorbed birch xylan. During the bleaching process, better mechanical properties were obtained with shorter bleaching times and lower bleaching temperatures, initial pHs, and MgSO4 dosages. However, the optical properties were improved as the bleaching time, temperature, initial pH, and MgSO4 dosage were increased. The adsorption of birch xylan could effectively modify the mechanical properties of paper made from brown pulp under various phases.

Directional dependence of the mechanical properties of aged paper

Tensile testing was used to measure the mechanical properties of paper at various orientations relative to the fiber alignment of paper. New, artificially aged, and naturally aged paper were shown to behave as orthotropic materials, as shown by the orientation dependence of the Young's modulus, E. The Young's modulus data could be fit to a simplified equation, indicating the shear modulus is relatively insensitive to the specific orientation. The shear modulus as measured by ultrasonic measurements was similar to that measured by fitting the modulus vs orientation data obtained by tensile testing to the orthotropic equation. The inelastic tensile strength could also be described by a simple non-linear equation, and there was more deviation of the data from this prediction for brittle papers than for non-brittle papers. The extent of fiber orientation (Ex/Ey) could be inferred by either the Young's modulus or the tensile strength, TS, i.e. Ex/Ey ≈ TSx/TSy. The measured strains were lowest for brittle paper. All brittle papers gave a strain to failure <1% whereas the non-brittle papers gave a strain to failure >1%.

A comparative study of the effect of cellulose-based deep coating and pulp refining on the structural and mechanical properties of paper

A new coating method was developed, based on cellulose regenerated from an N-methylmorpholine N-oxide (NMMO) solution applied to paper. In particular, the purpose of this study was to compare the effectiveness of the “deep coating” method using cellulose regenerated from NMMO solution and the classic pulp refining process as methods to improve paper mechanical properties and overall quality. The “deep coating” name comes from the fact that the coating process is combined with subsequent heating of the coating before its final solidification. As a result of this operation, deep penetration of the cellulosic solution into the paper structure occurs. This increases the contact surface of the solution with the cellulosic fibers, which increases the strength properties of the paper structure. It was found that the cellulosic coating increased the apparent density of the paper, the tensile strength, the elongation, the resistance to bursting, and the double fold number. However, the coating also decreased the air permeability and the tear resistance of the paper samples. Despite some technological difficulties, this method could be an attractive solution in the case of a need for additional functionalization of a paper structure.

Gellan Gum Hydrogel as an Aqueous Treatment Method for Xuan Paper

Abstract Aqueous cleaning of works of art on paper is one of the most important and delicate steps in a conservation process. It allows the removal of inorganic (metals) and organic substances, such as degradation products and other contaminants. These substances are responsible for yellowing, weakening, and loss of mechanical properties of paper. In this article, the cleaning effect of gellan gum was assessed on xuan paper, a traditional Chinese paper different in composition and papermaking technology compared to many Western papers. To assess the effect of gellan gum on xuan paper, its characteristics were studied before and after cleaning utilizing non-invasive and micro-invasive techniques. Results were compared to those obtained when treating Western papers and indicated that gellan gum can be applied effectively for aqueous cleaning of xuan paper.