Burst Strength Research Articles

Effects of montmorillonite nanoclay on the properties of chemimechanical pulping paper

The effects of nanoclay were studied relative to the physical, mechanical, optical, and morphological properties of chemimechanical pulping papers. Nanoclay was incorporated at 0%, 2%, 4%, 6%, 8%, or 10%. To increase the retention, 1% cationic starch was used in all test papers. Handsheets (60 g/m2 in weight) were tested to determine their physical, mechanical, optical, and morphological properties. Up to 2% nanoclay increased the tensile strength; at values greater than 2%, the tensile strength decreased. The addition of up to 4% nanoclay increased roughness; between 4% and 10% nanoclay, roughness decreased. With 10% nanoclay, the tear strength, burst strength, and brightness decreased, but the air resistance, opacity, and yellowness increased. Scanning electron microscopy showed that the nanoclay filled the pore spaces between fibers, thus increasing air resistance. X-ray diffraction patterns indicated an intercalated structure.

Investigation of the Effect of Using Activated Sludge Treated with Acetic Acid on Physical and Strength Properties of Recycled Pulp

This study aimed to scrutinize chemical treatment of Mazandaran Wood and Paper mill activated sludge with 3 % acetic acid for the manufacture of environmentally eco-friendly bio composite. In this study, the paper pulp required was obtained from the waste newsprint paper. The activated sludge was treated in a beaker for 3 min in 3 % acetic acid and then in a water bath at 75 and 100 °C for 45 and 90 min. After that, the treated activated sludge was mixed and refi ned with waste newsprint paper pulp at ratios of 0, 5, 10, 15 and 20 %. The test specimens were prepared according to TAPPI standard and the physical properties (water absorption and porosity) and mechanical (tensile strength, tear strength, ring crush test, burst strength and folding strength) were measured. The results showed that the activated sludge treatment caused the increase in tear strength, ring crush test, burst strength and porosity as well as the decrease in water absorption, tensile strength and folding strength. FT-IR spectrum of the treated samples showed that the treatment with acetic acid strengthened and activated the functional groups on the surface of activated sludge fi bers. The activated sludge added at a level of 5 % at 100 °C for 90 min as well as at a level of 20 % at 75 °C for 45 min was more suitable than other treatments.

Self-assembled all-polysaccharide hydrogel film for versatile paper-based food packaging

Paper-based packaging generally has poor performances in the gas/oil barriers. This work reports a paper-based packaging material prepared via the modification of conventional papers with TEMPO-oxidized cellulose nanofibers (TOCN)/cationic guar gum (CGG) hydrogel film. Specifically, the hydrogel film modification was realized through a layer-by-layer deposition on paper. The hydrogel film modification significantly improved the mechanical and barrier properties of the paper. Specifically, the 4-layer hydrogel film modified paper showed a tensile strength of 34.03 MPa and a burst strength of 510 kPa, respectively. In contrast, the unmodified paper exhibited a tensile strength of 26.78 MPa and a bursting strength of 388 kPa. The packaging performance of this TOCN/CGG hydrogel film modified paper was demonstrated via the fresh mooncake packaging test. Such hydrogel film not only provided the oil resistance, but also maintained the mooncake's freshness. This material can serve as a green and sustainable food packaging.

Synthesis, characterization, and utilization of potato starch nanoparticles as a filler in nanocomposite films

The nanoparticles for the preparation of nanocomposite starch films were synthesized from potato starch using the acid hydrolysis method. The films were prepared by incorporating starch nanoparticles into the film formulation at 0.5, 1, 2, 5, and 10% level of total starch. The control starch film was prepared without the incorporation of starch nanoparticles (SNPs) in film formulation. The starch and SNPs were analyzed for physicochemical and morphological properties. The absorption capacity of SNPs for water and oil was significantly (p < 0.05) lower as compared to native starch. Whereas, the swelling power and solubility of SNPs were significantly (p < 0.05) higher than the swelling power and solubility of starch, respectively. The starch granules were oval and spherical with regular surfaces whereas the SNPs had irregular cracked exteriors spaces. The water vapor transmission rate (WVTR) from nanocomposite starch films was significantly (p < 0.05) lower than the control starch film. The burst strength of films was increased significantly (p < 0.05) with an increased level of SNPs incorporation in film formulation. The incorporation of SNPs increased film thickness and biodegradability. Thus, the present study revealed that the incorporation of SNPs in film formulation resulted in improved film properties.

Pine needles lignocellulosic ethylene scavenging paper impregnated with nanozeolite for active packaging applications

The pines needle falls approximately 2–3 ha−1 year−1 on the forest floors resulting in a considerable amount of lignocellulosic biowaste. The present study aimed to develop pine needles based lignocellulosic active paper and investigate the effect of 5, 20, and 30% (v/w) nano zeolite addition on the physical, mechanical, and microstructural property of the papers. The developed papers were characterized by scanning electron microscope, transmission electron microscope, Fourier transform infrared spectrometer, and X-ray diffraction. As the zeolite concentration was increased from 5% to 30% in the paper, enhanced water permeability was seen from 5.18 ± 0.34 - 3.88 ± 0.33 g/cm2/day (PN/ZL 30% paper). The addition of 5% zeolite increased the tensile and burst strength from 19.53 ± 3.53 Nm/g and 3.63 ± 0.23 kg/cm2, respectively. The porosity was increased from 340 ± 20 to 1170 ± 60, and Cobb value increased from 338.3 ± 1.5- 406.7 ± 1.5 g/m2. The alterations in terms of surface microstructure in the paper with 20, 30% zeolite were noticed whereas XRD illustrated the high compatibility among the lignocellulosic network of pines and zeolite. The pine needle paper with 30% zeolite possessed remarkable ethylene scavenging properties (62%), opening a way to valorize pine needle waste for food packaging application.

A simple method of simultaneously endowing paper or fluff pulp with both high softness or appropriate fluffing properties and antimicrobial properties

As the living standard improves, disposable sanitary and household paper requires not only softness or easy to fluff in a dry state, but also good antibacterial property. In this study, a series of alkyl quaternary ammonium salts (AQAS), a kinds of antibacterial-debonding agents, were synthesized by using a two-step process. The SN2 nucleophilic substitution reaction was designed between triethanolamine and sulfoxide chloride, and followed subsequent quaternization by tertiaryamines with different long alkyl chains. The obtained products can be used as an antibacterial and softening/debonding agent for improving the performance of paper or fluff pulp. The results showed that these new compounds can endow antibacterial function and high softness to paper or control appropriate burst strength to fluff pulp. These AQAS products can be not only used in daily disposable sanitary products, but also have potential applications in other products such as glass spacer paper, advanced household paper, or antibacterial tissue products to prevent microbial contamination.

On arginine‐based polyurethane‐blends specific to vascular prostheses

AbstractPolymer blends based on Tecoflex™ and an experimental aliphatic polyurethane (HMDI‐PCL‐arginine stands for 4,4 (metylene‐biscyclohexyl) isocyanate ‐ poly (ε caprolactone) diol, SPUUR stands for segmented poly(urea)urethanes using amino acid of L‐Arginine as chain extender) were obtained by solvent casting, and further studied by fourier transform infrared (FTIR) and Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis, and X‐ray diffraction (XRD). Their biological performances were assessed in terms of hemocompatibility and Human umbilical vein endothelial cell (HUVEC) cytotoxicity. Tensile properties of dumbbell specimens were compared to longitudinal and circumferential tensile properties of tubular vascular graft. FTIR showed that as the SPUUR content increased in the blend, absorptions at 2860 cm−1 increased, carbonyl absorptions at 1724 cm−1 broaden and the small peak at 2796 cm−1, typical of Tecoflex™ disappeared. Raman spectroscopy showed that the low intensity carbonyl absorption at 1724 cm−1 also increased with SPUUR content. DSC allowed detection of PCL soft segment melting (Tm = 50°C) in agreement with X‐ray reflections at 21.3° and 23.6°, assigned to SPUUR. However, no improvements in thermal stability were detected by TGA by blending. The addition of SPUUR to Tecoflex™ improved hemocompatibility and HUVEC cytotoxicity. The vascular grafts performance showed that 40% SPUUR blends exhibited the highest force in the longitudinal test whereas 50% SPUUR blends showed the highest circumferential force. Pressure burst strength was higher than 1000 mmHg for all blends. Overall, these blends can be used for high caliber vascular grafts.

PRODUCTION, OPTIMIZATION AND DEINKING CAPACITY OF ALKALINE CELLULASE PRODUCED FROM MUCOR CIRCINELLOIDES WSSDBS2F1

An alkaliphilic Mucor circinelloides WSSDBS2F1 strain, with the ability to produce endoglucanase and exoglucanase enzymes, was isolated from decomposing bagasse, originating from a sugar processing mill in Punjab, India, and then screened. A pH range of 7-11, temperature of 30-60 °C, incubation period of 4-12 days, different lignocellulosic waste and nitrogen sources were investigated for optimum production of cellulase enzyme. Response Surface Methodology (RSM) was the statistical tool used for optimization of endoglucanase and exoglucanase production, following the one-factor-at-a-time approach. The optimized endoglucanase was further evaluated for its ability to deink waste paper, compared to chemical deinking. It was found that the enzymatically deinked pulp had high ISO brightness, tensile, burst and tearing strength, as compared to chemically deinked and control pulps. Scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR) were also used to confirm the action of the endoglucanase enzyme on waste paper.

Evaluation of a Novel Absorbable Mesh in a Porcine Model of Abdominal Wall Repair.

Background:Bioabsorbable meshes have seen increasing clinical use to reinforce soft tissue, and exist on a spectrum of strength loss versus absorption: several retain their strength for months, but remain in situ for years. Others lose strength fully by 6 weeks. An intermediate profile, with some strength for 3 -4 months, but consistent absorption in less than a year, may be an optimal balance of near-term support and long-term safety. In this large animal study, we evaluate such a mesh (DuraSorb, SIA), assessing its utility in a porcine model of abdominal wall repair.Methods:Two full-thickness defects were created in the abdominal walls of nine Yucatan swine via midline approach and repaired preperitoneally with either DuraSorb or long-lasting control mesh (TIGR, Novus Scientific). At 30 days, 3 months, and 1 year, the implantations were assessed by clinical pathology, post-necropsy histopathology, and burst strength testing.Results:No device-associated complications were found in vivo, at necropsy, or histologically. DuraSorb was well-integrated and vascularized by 30 days. DuraSorb demonstrated minimal/mild inflammation and fibroplasia, and lower inflammatory scores when compared with TIGR at all time points (P < 0.05). Burst strength of the repair sites was higher than adjacent abdominal wall at all time points (P < 0.05).Conclusions:DuraSorb provided durable long-term support, minimal inflammation, and consistent absorption in this porcine model of abdominal wall repair, as compared to a long-term control. Clinical data is needed, but these results suggest that this mesh provides adequate structural support while potentially reducing long-term device reactions.

Chemical, thermal, and mechanical properties and ultraviolet transmittance of novel nano‐hydroxyapatite/polyethylene terephthalate milk bottles

AbstractPolyethylene terephthalate (PET)/nano‐hydroxyapatite (nHAp) composite granules were obtained using twin‐screw extruder. Preforms were prepared by injection molding and then PET/nHAp bottles were produced by blow molding. For PET bottles with nHAp, the migration amounts of carboxylic acid (COOH), acetaldehyde (AA), diethylene glycol (DEG), and isophthalic acid (IPA); glass transition temperature (Tg); melting temperature (Tm); and the maximum crystallization temperature (Tcry) were measured. The load‐carrying capacity, burst strength, stress cracking, and regional material distribution tests were carried out on the bottles. X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and ultraviolet transmittance analyses were conducted to explain the changes in mechanical, chemical, physical properties, and light transmission of bottles. It was found out that the COOH amount increased and the AA content decreased with increasing nHAp amount. On the other hand, no change was observed in the amounts of DEG and IPA. Although the mechanical properties such as load‐carrying capacity and burst strength of the bottles have improved, it has been determined that the standard environmental stress crack resistance test procedure cannot be applied to such a composite. Experimental findings indicate that nHAp disrupts the chemical structure of PET and it isolates harmful chemicals such as AA by forming intermolecular bonds. Moreover, with the addition of up to 0.8% nHAp, PET bottles block the light transmission approximately 80% within 400–700 nm wave length zone. The study demonstrates that the PET/nHAp composite bottles can be used in the food industry, particularly in the packaging of milk and milk products which are vulnerable to light exposure.

Evaluating effects of activated sludge and nanochitosan on physical and strength properties of recycled pulp

The present research aims to shed light on the effect of activated sludge (from a paper mill) and nanochitosan on the physical and strength properties of recycled pulp. Firstly, activated sludge was treated with 3% acetic acid for 30 min and then placed in a beaker for 90 min at 100 °C. Then, the ingredients were mixed and refined with recycled newsprint pulp in different proportions (0, 5, 10, and 15%). Finally, 2% nanochitosan was optionally added. Test specimens were prepared according to TAPPI standards with a basis weight of 120 g/m2, and their physical (water absorption) and strength (tear strength, tensile strength, burst strength, and ring crush test) properties were measured and compared. The results showed that with the increase of untreated activated sludge in recycled paper pulp, the indicators of tear resistance, ring crush test, and burst strength decreased and water absorption increased. Strength properties increased and water adsorption decreased when adding activated sludge treated with 3% acetic acid. Through the addition of nanochitosan to activated sludge treated with acetic acid, a significant increase in strength properties and a decrease in water absorption were observed.

Fundamental Study of the Production of Paper Ash Made from Paper Sludge II : Development of Paper Ash Application Technology to Improve the Bulk and Save Drying Energy of Paperboard

In this study, paper ash generated during the incineration process of paper sludge was applied to measure the bulk, strength, and drying energy reduction of paperboard to assess the possibility of using it as an inorganic additive in paperboard mills. Three types of paper ash were fabricated by incineration, crushed, and fractionated with three different screen sizes, and their physical properties were measured. The fabricated paper ashes were added to Korean old corrugated containers (KOCC) stock to make handsheets, and their physical properties and drying energy reduction were determined. In addition, paper ash particles classified into 200 mesh screens were surface-modified with cationic polyacrylamide (C-PAM), and the handsheets were manufactured to analyze the strength improvement effect of paperboard. The bulk and the drying energy reduction improved as the paper ashes were added into the KOCC stock, but the tensile index, compression index, and burst strength decreased. In particular, the higher the average particle size of the paper ash, the higher the bulk and the drying energy reduction, but the lower the strength. The surface modification of the paper ash with C-PAM was effective in improving the strength. Therefore, paper ash made of paper sludge collected from specialty paper mills is effective in improving the bulk and drying energy reduction of paperboard, and surface modification with C-PAM is required to prevent the deterioration of paper strength.

Evaluation methods for estimation of Weibull parameters used in Monte Carlo simulations for safety analysis of pressure vessels

Abstract The test data for static burst strength and load cycle fatigue strength of pressure vessels can often be well described by Gaussian normal or Weibull distribution functions. There are various approaches which can be used to determine the parameters of the Weibull distribution function; however, the performance of these methods is uncertain. In this study, six methods are evaluated by using the criterion of OSL (observed significance level) from Anderson-Darling (AD) goodness of Fit (GoF), These are: a) the norm-log based method, b) least squares regression, c) weighted least squares regression, d) a linear approach based on good linear unbiased estimators, e) maximum likelihood estimation and f) method of moments estimation. In addition, various approaches of ranking function are considered. The results show that there are no outperforming methods which can be identified clearly, primarily due to the limitation of the small sample size of the test data used for Weibull analysis. This randomness resulting from the sampling is further investigated by using Monte Carlo simulations, concluding that the sample size of the experimental data is more crucial than the exact method used to derive Weibull parameters. Finally, a recommendation is made to consider the uncertainties of the limitations due to the small size for pressure vessel testing and also for general material testing.

Improvement of loads calculation of the perforated liner in a geothermal production well

The integrity of perforated liners is crucial in geothermal production wells and this should be well designed according to correct standards. The available geothermal standards, such as the New Zealand Standard, NZS2403:2015, provides a general but less detailed discussion of geothermal perforated liner system design considerations.This research aimed to improve the limitations of NZS2403:2015 by calculating and evaluating the dynamic loads of perforated liner during four phases: borehole drilling and liner installation, flow testing, stand-alone production, and production during the injection operation. The data from production well HCE29 and injection well HCE29A, Dieng Field, Indonesia, were used in this research. In every phase, perforated liner yield strength changed, and load mechanisms varied between 1.3-2.7 and 1.6–4.6 times of the actual liner burst and collapse strength, respectively, and these lead to perforated liner failure and its lifetime reduction. The calculation results, combined with the significant production decline and production casing failure, indicated the perforated liner failure. The results also showed when it was mandatory to revise operation at later phases and to conduct appropriate maintenance according to actual perforated liner condition. Furthermore, this study can be used as a basis of future wells design and operation related to perforated liner.

Evaluation of the probe burst test as a measure of strength for a biologically-engineered vascular graft

Biologically-engineered vascular grafts have the potential to provide a viable alternative to donor vessels and synthetic grafts. In congenital heart defect patients, the need is even more dire since neither has the capacity to provide somatic growth. To ensure clinically-used grafts perform to accepted standards, mechanical strength is a crucial consideration, with burst testing being considered as one key metric. While ISO 7198 standards for prosthetic vascular grafts provide multiple choices for burst testing, most studies with tissue-engineered grafts have been performed with only pressure burst testing. Here, we compare the performance of a decellularized tube of collagenous matrix grown from dermal fibroblasts, possessing circumferential fiber alignment and anisotropic tensile properties, as determined from pressure and probe burst testing. The two burst tests showed a strong correlation with each other and with tensile strength. Further, relatively weak and strong batches of grafts showed commensurate differences in pressure and probe burst values. Both probe burst and tensile strength measurements in the central and edge regions of the grafts were similar in value, consistent with homogenous collagen content and microstructure throughout the grafts as indicated by histology, in contrast to ovine femoral and carotid arteries similarly tested. Finite element analysis of the probe burst test pre-failure for a homogeneous, isotropic approximation of the matrix constitutive behavior indicated dependence of the (inferred) effective failure stress achievable on probe diameter. The results indicate a probe burst test in a sampled edge region of this biologically-engineered graft provides a representative measure of burst strength of the entire graft.

Modelling the Effect of Resin-Finishing Process Variables on the Dimensional Stability and Bursting Strength of Viscose Plain Knitted Fabric Using a Fuzzy Expert System

The application of cross-linking resin is an effective method for improving and controlling dimensional stability, such as the shrinkage of viscose single jersey knits. However, such treatment often leads to a significant deterioration in the bursting strength of treated fabrics. In this regard, resin treatment using a softening agent can be an additional potential solution for retaining the bursting strength of treated fabrics. Resin treatment is one kind of chemical finishing process that inhibits cellulosic textile fibre swelling during wetting, provides fibre resistance to deformation and prevents shrinkage. The key objective of this study was to model the effect of resin-finishing process variables for predicting the shrinkage control and bursting strength of viscose single jersey knitted fabrics. The MATLAB (Version 8.2.0.701) fuzzy expert system was used to model the optimum resin and softener concentrations, as well as the best curing time for the prediction of maximum shrinkage control with a minimum loss in fabric bursting strength. The optimal process variables were found to be a resin concentration of 75 g/l, a softener concentration of 45 g/l and a curing time of 225 seconds. The fuzzy expert model developed in this study was validated using experimental data. It was found that the model has the ability and accuracy to predict fabric shrinkage and bursting strength effectively in the non-linear field.

Impacts of degree of substitution of quaternary cellulose on the strength improvement of fiber networks

The degree of substitution (DS) of cellulose derivative is significantly associated with its properties. In this paper, a series of quaternary cellulose (QC) samples with different DS (ranging from 0.16 to 0.51) were synthesized with assistance of microwave and their relationship with strength improvement of fiber networks was investigated systematically. QCs were characterized by elemental analysis, FT-IR, 1H NMR, and TGA, etc. The results showed that the cationic quaternary ammonium salt group was successfully grafted onto the backbones of cellulose chains and the thermal stability was associated inversely with the DS of QCs. However, the results of strength test for the fiber networks from secondary fiber of old corrugated containers showed that the tensile and burst strength was enhanced by addition of QCs, and their performance was positively correlated their DS. The best result achieved in this investigation was in the case of QC with DS of 0.51, with increments of tensile and burst strength 6.17% and 11.68%, respectively, at a dosage of 1.0 wt% based on oven-dry pulp. This investigation highlights the importance of DS of QC to its application in strength improvement for fiber networks.

Effect of Expansion Ratio and Wall Thickness on Large-Diameter Solid Expandable Tubular After Expansion

Abstract The large-diameter solid expandable tubular (SET) with a smaller wall thickness faces the risk of internal pressure burst and external squeeze collapse in repairing damaged casing well. The internal pressure and external squeezing resistance calculation of the tubes using the analytical method require many expansion experiments and postexpansion tensile experiments, resulting in high costs and low efficiency. This paper gives a set of laboratory expansion and postexpansion performance test, which is based on the laboratory experiment and mechanical properties of material expansion. Two materials are studied: 316 L and 20G. Then it analyses the error and causes of the error in the traditional analytical algorithm. Besides, it establishes an accurate finite element (FE) model to study the quantitative influence of expansion ratio and wall thickness on the burst strengths and collapse strengths of the tube. The results show that the toughness and hardening ratio of 316 L is better than 20G at the same expansion ratio. The numerical simulation results of the model can effectively simulate the expansion process and the mechanical properties of SET in good agreement with the laboratory test results. The expansion ratio and wall thickness affect the mechanical properties after expansion. Thus the quantitative laws of the expansion driving force, internal pressure resistance, and external squeezing resistance under different variables are summarized. To ensure the integrity of the reinforced wellbore, the expansion ratio should not exceed 12.7%. The current study lays a theoretical basis and technical support for optimizing SET and preventing downhole accidents.

Silica Aerogel Application to Polyester Fabric for Outdoor Clothing

Most producers want to have a cheap, one-step system that will successfully apply multi-finishing operations without affecting any of the desired textile properties. Silica aerogel, used for isolation purposes in different areas such as construction, has been used in textile finishing in this study. 100 % polyester fabrics, which are widely used in outerwear, were impregnated with silica aerogel paste and binder at lower temperature and time than that applied for conventional coating method, providing decreased energy consumption. The samples were tested for wettability, soil release and hydrophobicity both before and after repeated laundering. Burst strength tests were also performed to investigate strength properties of the fabrics. The presence of silica groups on the treated fabrics was confirmed by FTIR spectra and thermal characteristics of the samples were evaluated by using differential scanning calorimeter (DSC). The results showed that aerogel impregnated fabrics provide superhydrophobic properties with a contact angle of around 170° and improved soil release properties even at very low add-ons. It was also found that the silica aerogel treatment has no adverse effect on the fabric appearance or strength properties.

Chemical-technological phenomena occurring during borehole cementing operations in terms of casing design, with particular emphasis on their collapse and burst strength

One of the most important issues that needs to be addressed in the borehole design process is the optimal design of the borehole structure, including the appropriate selection of individual casing columns and their setting given the assumed geological and cementing-technical conditions. Specific geological and technical conditions imply a number of both conditions and constraints. A kind of dimensional unification of pipes adopted by API many decades ago, i.e. a series according to the outer diameter of the pipes, constitutes the main natural constraint. Other elements of this unification, such as a series of steel grades or of classic and PREMIUM thread connections were implemented gradually as drilling technology developed. Regardless of these conditions, one thing always remains the same when designing casing and selecting production tubing, i.e. maintaining the balance between the existing loads acting on the pipes during the drilling process and operation of the borehole and the minimum mechanical strength of the pipes. This article reviews the methods and guidelines for casing pipe designing published by API and of computer programs, including StressCheck, which is currently one of the commonly used pipe design tools. The strength issues discussed in the article refer mainly to the pipe body, ignoring the complex issue of the strength of the thread connections, especially those of PREMIUM type, whose qualification is not subject to API standards, but to the guidelines contained in ISO 13679.