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

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5376-5389
Author(s):  
Marta Krysztof ◽  
Konrad Olejnik ◽  
Piotr Kulpiński ◽  
Aleksandra Erdman ◽  
Elżbieta Sąsiadek

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.

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 548 ◽  
Author(s):  
Leonid Agureev ◽  
Valeriy Kostikov ◽  
Zhanna Eremeeva ◽  
Svetlana Savushkina ◽  
Boris Ivanov ◽  
...  

The article presents the study of alumina nanoparticles’ (nanofibers) concentration effect on the strength properties of pure nickel. The samples were obtained by spark plasma sintering of previously mechanically activated metal powders. The dependence of the grain size and the relative density of compacts on the number of nanofibers was investigated. It was found that with an increase in the concentration of nanofibers, the average size of the matrix particles decreased. The effects of the nanoparticle concentration (0.01–0.1 wt.%) on the elastic modulus and tensile strength were determined for materials at 25 °C, 400 °C, and 750 °C. It was shown that with an increase in the concentration of nanofibers, a 10–40% increase in the elastic modulus and ultimate tensile strength occurred. A comparison of the mechanical properties of nickel in a wide range of temperatures, obtained in this work with materials made by various technologies, is carried out. A description of nanofibers’ mechanisms of influence on the structure and mechanical properties of nickel is given. The possible impact of impurity phases on the properties of nickel is estimated. The tendency of changes in the mechanical properties of nickel, depending on the concentration of nanofibers, is shown.


2021 ◽  
Vol 36 (1) ◽  
pp. 111-119
Author(s):  
Behzad Jafari Mohammadabadi ◽  
Kourosh Shahriar ◽  
Hossein Jalalifar ◽  
Kaveh Ahangari

Rocks are formed from particles and the interaction between those particles controls the behaviour of a rock’s mechanical properties. Since it is very important to conduct extensive studies about the relationship between the micro-parameters and macro-parameters of rock, this paper investigates the effects of some micro-parameters on strength properties and the behaviour of cracks in rock. This is carried out by using numerical simulation of an extensive series of Uniaxial Compressive Strength (UCS) and Brazilian Tensile Strength (BTS) tests. The micro-parameters included the particles’ contact modulus, the contact stiff ness ratio, bond cohesion, bond tensile strength, the friction coefficient and the friction angle, and the mechanical properties of chromite rock have been considered as base values of the investigation. Based on the obtained results, it was found that the most important micro-parameters on the behaviour of rock in the compressive state are bond cohesion, bond tensile strength, and the friction coefficient. Also, the bond tensile strength showed the largest effect under tensile conditions. The micro-parameter of bond tensile strength increased the rock tensile strength (up to 5 times), minimized destructive cracks and increased the corresponding strain (almost 2.5 times) during critical stress.


2019 ◽  
Vol 37 (4) ◽  
pp. 235-248
Author(s):  
Imene Ghezal ◽  
Ali Moussa ◽  
Imed Ben Marzoug ◽  
Ahmida El-Achari ◽  
Christine Campagne ◽  
...  

The purpose of this research was to evaluate mechanical properties of a waterproof breathable fabric. A spacer knit with a cotton inner face and a polyester (PET) outer face was coated in order to obtain a waterproof breathable fabric. The applied coat was a mixture of an acrylic paste and a fluorocarbon resin. The treated fabric has undergone several tests to evaluate its mechanical properties. Tensile strength, flexural strength, abrasion resistance, and wrinkle recovery behavior were measured and discussed. After the coating treatment, the fabric was rigidified by 25% and 19% in wale and course directions, respectively. The coated PET face of the spacer fabric was not altered even after 125,000 abrasion cycles. A stiffer fabric was obtained after the coating treatment. However, fabric recovery behavior was ameliorated by 78% and 72% according to wale and course directions, respectively. The coated fabric can be used to produce raincoats and jackets.


2019 ◽  
Vol 25 (3) ◽  
pp. 316-321
Author(s):  
Florentina SEDERAVIČIŪTĖ ◽  
Jurgita DOMSKIENĖ ◽  
Ilze BALTINA

The article presents an experimental study of mechanical properties of cellulose biofilm produced by bacterial fermentation process. Naturally derived biomaterial has great current and potential applications therefore the conditions of material preparation as well as control and prediction of mechanical properties is still a relevant issue. Bacterial cellulose was obtained as a secondary product from Kombucha drink. Presented technique for material preparation and drying is particularly simple and easy to access. The influence of drying temperature (25 °C, 50 °C and 75 °C) on the sample size (thickness and planar dimensions) and mechanical properties (tensile and bursting strength) of cellulose biofilm has been evaluated. It was estimated that during drying biofilm specimens lost up to 92 % of weight and up to 87 % of thickness therefore planar specimen dimensions varied insignificantly. The study showed that the drying temperature is important for optimum strength properties of bacterial cellulose biofilm. The maximum tensile strength (27.91 MPa) was recorded for the samples dried at temperature of 25 °C, when the moisture from the biomaterial is removed gradually and good deformation properties are ensured (respectively tensile extension 18.8 %). Under higher drying temperature biomaterial shows lower values of tensile strength and higher values of bursting strength. The maximum bursting strength (57.2 MPa) was recorded for samples dried at 75 °C when punch displacement changes were insignificant for all tested samples (from 17.8 mm to 21.7 mm). DOI: http://dx.doi.org/10.5755/j01.ms.25.3.20764


2014 ◽  
Vol 910 ◽  
pp. 230-233
Author(s):  
Jia Horng Lin ◽  
Ying Huei Shih ◽  
Ching Wen Lin ◽  
Ching Wen Lou

Polymeric material, which is commonly used in packaging, has been widely applied due to the fact that it is lightweight and chemical resistant. Being non-degradable, polymeric waste can thus only be eliminated by burning, and subsequently, there is a rising need for degradable polymeric material to manage this manner of disposal. This study thus uses degradable, low-melting-point polylactide (LMPLA) fibers and recycled polyester (RPET) fibers to make nonwoven fabrics for packaging. The tensile strength, tear strength, and air permeability of the nonwoven fabrics are then tested. The experiment results show that a 40% of RPET fibers can effectively promote the mechanical properties of the LMPLA nonwoven fabrics.


2014 ◽  
Vol 1040 ◽  
pp. 772-777 ◽  
Author(s):  
Lilia I. Shevtsova ◽  
Michail A. Korchagin ◽  
Alexander Thömmes ◽  
Vyacheslav I. Mali ◽  
Alexander G. Anisimov ◽  
...  

In this paper structure and mechanical properties of Ni3Al intermetallic compound was studied. The materials was fabricated according to different schemes, which combined mechanical alloying of Ni and Al powders, self-propagating high temperature synthesis (SHS) and spark plasma sintering (SPS). Relative density of all sintered samples was ~ 97 %. Microhardness of the sintered materials ranged from 6100 to 6300 MPa. SPS of 86.71 % wt. Ni and 13.29 % wt. Ni powder at 1100 °C led to formation of material with the highest level of tensile strength equal to 400 MPa.


2007 ◽  
Vol 345-346 ◽  
pp. 1027-1030
Author(s):  
Sang Ll Lee ◽  
Moon Hee Lee ◽  
Jin Kyung Lee ◽  
Dong Su Bae ◽  
Joon Hyun Lee

The long-term corrosion strength properties for the carbon steels under pressurized water atmosphere have been investigated, in the conjunction with the detailed analysis of their microstructures. The corrosion test for carbon steels was carried out at the temperature of 200°C under a water pressure of 10 MPa. The corrosion test samples were maintained up to 50 weeks in the tube shaped reactor. The mechanical strength and the microstucture of carbon steels suffered from the long term corrosion test were evaluated by SEM, XRD and tensile test. The weight loss of carbon steel by the corrosion test was also examined. The tensile strength of carbon steels decreased with the increase of corrosion time under a pressurized water atmosphere, accompanying the creation of severe corrosion damages like stress corrosion crack.


Author(s):  
M. N. Meiirbekov ◽  
◽  
M. B. Ismailov ◽  

The paper presents published data on the effect of rubber elastomers on the strength properties of epoxy resin (ES) and carbon fiber. The introduction of 10% rubbers into ES ED-20 leads to an increase in compressive strength by 50%, tensile strength by 51%, impact strength by 133% and elongation by 128%. The optimal content of rubber with carboxyl groups for the OLDEN mixture was 10-12.5%, while the increase in compressive strength was 48%, impact strength - 73% and elongation - 187%. For DER 331 resin, the study was conducted with two hardeners Piperidine and DETA. The best results for Piperidine hardener were obtained on rubber with hydroxyl groups, with its optimal content of 2.5%, impact strength increased by 170%. For the hardener DETA, the best results were obtained on rubber with carboxyl groups at its optimal content of 10%, the increase in impact strength was 66%. When modifying carbon fiber with rubbers, it leads to a significant increase in the yield strength in tension by 42%, the modulus of elasticity in bending by 63%, and with a slight loss of impact strength.


2021 ◽  
Vol 8 ◽  
Author(s):  
Shi Wang ◽  
Xuepeng Song ◽  
Meiliang Wei ◽  
Wu Liu ◽  
Xiaojun Wang ◽  
...  

The tailings and rice straw are waste by-products, and the storage of tailings on the ground and the burning of rice straws will seriously damage the ecological environment. In this study, the effect of different contents of alkalized rice straw (ARS; rice straw was alkalized with 4% NaOH solution) on the mechanical properties and microstructure of cemented tailings backfill (CTB; ARSCTB) was studied through uniaxial compressive strength (UCS), scanning electron microscopy (SEM), and X-ray diffraction (XRD) tests. The results indicated that 1) the UCS of ARSCTB could be improved by ARS. However, with the increase in the ARS content from 0.1 to 0.4 wt%, the UCS showed a monotonous decreasing trend. The UCS improvement effect was best when the ARS content was 0.1 wt%, and at 7, 14, and 28 days curing ages, the UCS increased rate was 6.0, 8.3, 14.7% respectively. 2) The tensile strength of ARSCTB was generally higher than that of CTB and positively correlated with the ARS content. The tensile strength increase rate was 24.1–34.2% at 28 days curing age. 3) The SEM test indicated that the ARS was wrapped by cement hydration products, which improves its connection with the ARSCTB matrix. ARS performed a bridging role, inhibited cracks propagation, and provided drag or pulling force for the block that is about to fall off. Therefore, the mechanical properties of ARSCTB were enhanced. However, under high ARS content, the inhibition of ARS on hydration reaction and the overlap between ARS were not conducive to the improvement of the UCS of ARSCTB. 4) The post-peak residual strength and integrity effect of ARSCTB were greater. It is recommended to add 0.1–0.2 wt% ARS to the backfill with high compressive strength requirements such as the empty field subsequent filling mining method and the artificial pillar. 0.3–0.4 wt% ARS is incorporated into backfill with high tensile strength requirements such as high-stage filling with lateral exposure and artificial roof. This study further makes up for the blank of the application of plant fiber in the field of mine filling and helps to improve the mechanical properties of backfill through low-cost materials.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Samir Kasmi ◽  
Geoffrey Ginoux ◽  
Eric Labbé ◽  
Sébastien Alix

Purpose The purpose of this study is to test a flexible polymer with different characteristics compared to other classical polymers mostly used in the additive manufacturing process, and to improve its mechanical properties and microstructure, by modifying different printing parameters, to make it more suitable for various industrial applications. Design/methodology/approach Seven parameters were tested, namely, nozzle temperature, bed temperature, layer thickness, printing speed, flow rate, printing time gap between two successive printed layers and raster orientation. Rheological characterizations were conducted to evaluate the influence of nozzle temperature on the melt viscosity of thermoplastic polyurethane (TPU). The effect of thermal printing parameters on the crystallinity behavior was explored. Tomographic characterizations were realized to measure the porosity and evaluate the internal structure quality of printed specimens. Findings Increases of the nozzle temperature, bed temperature, layer thickness and flow rate had a positive influence on the tensile strength properties of TPU with a reduction of porosity. Higher printing speeds created defects and negatively influenced the strength properties of TPU. An increase in the printing time gap between layers led to poor interlayer adhesion and decreased the tensile strength. Specimens with layers all oriented parallel to the loading direction exhibited superior mechanical properties compared to other raster orientations. Originality/value Thermoplastic elastomers are a unique class of polymers characterized by the combined thermal, chemical and mechanical properties of their elastomer and thermoplastic parts. TPU elastomer, as one of the elastomer families, has found an important position in the bioengineering and three-dimensional printing industry. This study reports a comprehensive study of the impact of additive manufacturing parameters on the properties of TPU.


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