Influence of the micro-structural factors upon thermal and mechanical properties of various bag leathers

2017 ◽  
Vol 52 (3) ◽  
pp. 167-176 ◽  
Author(s):  
AK Mondal ◽  
PK Chattopadhyay
Keyword(s):  
Mechanical Properties ◽  
Morphological Characteristics ◽  
Crosslinking Density ◽  
Structural Factors ◽  
Melamine Formaldehyde ◽  
Elongation At Break ◽  
Indian Origin ◽  
Higher Temperature ◽  
Temperature And Pressure ◽  
Vegetable Tannins

Four different bag leathers, such as, Sheep Bag Leather (SBL), Buffalo Vegetable Tanned Leather (BVTL), Cow Drum Dyed Dry Milled Leather (CDDDML), and Cow Crocodile Print Leather (CCPL), were processed by different methods from respective wet-blues of Indian origin. Thermal degradation pro?le and mechanical properties of the samples were evaluated, and crosslink densities of each sample were measured by ?tment of Mooney-Rivlin equation on stress-strain plots. Morphological characteristics (e.g. ?bre structure, ?bre thickness, splitting etc.) of all the specimens were investigated by image analyses of SEM photomicrographs. The highest crosslinking density for BVTL was attributed to its higher ?bre and ?bril thicknesses coupled with rigorous retanning by vegetable tannins and syntans. Embossing at higher temperature and pressure reduced CCPL’s elongation-at-break value and hence stretchiness possibly due to the development of set properties within the CCPL matrix. SBL was noted to contain huge void spaces that increased its stretchiness, and melamine formaldehyde syntans showed pronounced in?uence in increasing the thermal resistance of both CCPL and CDDDML.Bangladesh J. Sci. Ind. Res. 52(3), 167-176, 2017

scholarly journals Influence of Controlled Epoxidation of an Asymmetric Styrene/Butadiene Star Block Copolymer on Structural and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 96
Author(s):  
Shankar P. Khatiwada ◽  
Ulrike Staudinger ◽  
Dieter Jehnichen ◽  
Gert Heinrich ◽  
Rameshwar Adhikari
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Chemical Modification ◽  
Tensile Modulus ◽  
Elongation At Break ◽  
Cylindrical Structures ◽  
Star Block Copolymer ◽  
Higher Temperature ◽  
Styrene Butadiene ◽  
Clear Increase

The chemical modification (namely the epoxidation) of a star shaped block copolymer (BCP) based on polystyrene (PS) and polybutadiene (PB) and its effect on structural and mechanical properties of the polymer were investigated. Epoxidation degrees of 37 mol%, 58 mol%, and 82 mol% were achieved by the reaction of the copolymer with meta-chloroperoxy benzoic acid (m-CPBA) under controlled conditions. The BCP structure was found to change from lamellae-like to mixed-type morphologies for intermediate epoxidation level while leading to quite ordered cylindrical structures for the higher level of chemical modification. As a consequence, the glass transition temperature (Tg) of the soft PB component of the BCP shifted towards significantly higher temperature. A clear increase in tensile modulus and tensile strength with a moderate decrease in elongation at break was observed. The epoxidized BCPs are suitable as reactive templates for the fabrication of nanostructured thermosetting resins.

ENHANCING THE REVERSION RESISTANCE, CROSSLINKING DENSITY AND THERMO-MECHANICAL PROPERTIES OF ACCELERATED SULFUR CURED CHLOROBUTYL RUBBER USING 4,4′-BIS (MALEIMIDO) DIPHENYL METHANE

2019 ◽  
Vol 92 (1) ◽  
pp. 110-128 ◽  
Author(s):  
Shibulal Gopisathi ◽  
Changsin Park ◽  
Yang Il Huh ◽  
Jinseok Jeon ◽  
Chang Hyun Yun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Crosslink Density ◽  
Kinetic Studies ◽  
Crosslinking Density ◽  
Low Level ◽  
Compression Set ◽  
Higher Temperature ◽  
Chlorobutyl Rubber

ABSTRACT Vulcanizates of chlorobutyl rubber (CIIR) with the accelerated sulfur generally exhibit poor crosslinking density owing to the low level of unsaturation in the backbone of CIIR. Therefore, the sulfur cured CIIR shows inferior thermo-mechanical properties at elevated temperature. In addition to this, the vulcanization of CIIR with accelerated sulfur is limited at higher temperature due to reversion. To solve these problems, 4,4′-bis (maleimido) diphenyl methane (BMDM) was applied as a crosslinking additive along with the accelerated sulfur. The detailed curing studies have proved that the presence of BMDM greatly enhanced the rheometric torque and the reversion resistance while curing CIIR with accelerated sulfur even at higher vulcanization temperature. Moreover, the crosslinking densities of the sulfur cured CIIR have increased by 109% with the use of 1 phr BMDM and further rose to 380% with 5 phr BMDM. The improved crosslink density could enable reduction of the compression set of the sulfur cured CIIR to around 40% at 100 °C when it was vulcanized in the presence of 5 phr BMDM. The kinetic studies revealed that incorporation of this additive does not adversely affect the original vulcanization behavior of CIIR with accelerated sulfur, instead it marginally improved the speed of the vulcanization.

scholarly journals Molecular Dynamics Simulation on Creep Mechanism of Nanocrystalline Cu-Ni Alloy

2021 ◽  
Vol 18 (1) ◽  
pp. 67
Author(s):  
Kasum Kasum ◽  
Fajar Mulyana ◽  
Mohamad Zaenudin ◽  
Adhes Gamayel ◽  
M. N. Mohammed
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
High Pressure ◽  
Molecular Dynamics Simulation ◽  
Creep Mechanism ◽  
Atomic Scale ◽  
Dynamics Simulation ◽  
Ni Alloy ◽  
Higher Temperature ◽  
Temperature And Pressure

Creep mechanism is an essential mechanism for material when subjected to a high temperature and high pressure. It shows material ability during an extreme application to maintain its structure and properties, especially high pressure and temperature. This test is already done experimentally in many materials such as metallic alloys, various stainless steel, and composites. However, understanding the creep mechanism at the atomic level is challenging due to the instruments  limitation. Still, the improvement of mechanical properties is expected can be done in such a group. In this work, the creep mechanism of the nanocrystalline Cu-Ni alloy is demonstrated in terms of molecular dynamics simulation. The result shows a significant impact on both temperature and pressure. The deformation supports the mechanisms as a result of the grain boundary diffusion. Quantitative analysis shows a more substantial difference in creep-rate at a higher temperature and pressure parameters. This study has successfully demonstrated the mechanism of creep at the atomic scale and may be used for improving the mechanical properties of the material.

850.0 and 852.0 ALUMINUM ALLOY BEARING BARS

Alloy Digest ◽  
1988 ◽  
Vol 37 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Heat Treating ◽  
Light Metal ◽  
General Purpose ◽  
High Ductility ◽  
Higher Temperature ◽  
Bearing Alloy

Abstract 850.0 ALUMINUM Alloy can be considered the general purpose light metal bearing alloy. Its good thermal conductivity keeps operating temperatures low. It has high ductility. In many applications it has been found to be superior to steel backed bearings. 852.0 ALUMINUM Alloy has higher mechanical properties making it suitable for heavier load and higher temperature applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength. It also includes information on corrosion resistance as well as heat treating and machining. Filing Code: Al-290. Producer or source: Federated Bronze Products Inc..

scholarly journals Effect of Organic Modifier Types on the Physical–Mechanical Properties and Overall Migration of Post-Consumer Polypropylene/Clay Nanocomposites for Food Packaging

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1502
Author(s):  
Eliezer Velásquez ◽  
Sebastián Espinoza ◽  
Ximena Valenzuela ◽  
Luan Garrido ◽  
María José Galotto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Food Packaging ◽  
Clay Nanocomposites ◽  
Organic Modifier ◽  
Thermal And Mechanical Properties ◽  
Chemical Safety ◽  
Elongation At Break ◽  
Fatty Food ◽  
Recycled Plastics ◽  
Thermal Stability Of

The deterioration of the physical–mechanical properties and loss of the chemical safety of plastics after consumption are topics of concern for food packaging applications. Incorporating nanoclays is an alternative to improve the performance of recycled plastics. However, properties and overall migration from polymer/clay nanocomposites to food require to be evaluated case-by-case. This work aimed to investigate the effect of organic modifier types of clays on the structural, thermal and mechanical properties and the overall migration of nanocomposites based on 50/50 virgin and recycled post-consumer polypropylene blend (VPP/RPP) and organoclays for food packaging applications. The clay with the most hydrophobic organic modifier caused higher thermal stability of the nanocomposites and greater intercalation of polypropylene between clay mineral layers but increased the overall migration to a fatty food simulant. This migration value was higher from the 50/50 VPP/RPP film than from VPP. Nonetheless, clays reduced the migration and even more when the clay had greater hydrophilicity because of lower interactions between the nanocomposite and the fatty simulant. Conversely, nanocomposites and VPP/RPP control films exhibited low migration values in the acid and non-acid food simulants. Regarding tensile parameters, elongation at break values of PP film significantly increased with RPP addition, but the incorporation of organoclays reduced its ductility to values closer to the VPP.

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

scholarly journals The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
High Energy ◽  
Electron Radiation ◽  
Elongation At Break ◽  
Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

scholarly journals Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1616
Author(s):  
Vincenzo Titone ◽  
Antonio Correnti ◽  
Francesco Paolo La Mantia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Moisture Content ◽  
Mechanical Testing ◽  
Hydrolytic Degradation ◽  
Slight Reduction ◽  
Biodegradable Polyester ◽  
Molding Process ◽  
Elongation At Break ◽  
Effect Of Moisture

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing—causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens.

scholarly journals Multicriteria Optimization of the Mechanical Properties in Laminated Seams

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2989
Author(s):  
Halina Szafranska ◽  
Ryszard Korycki
Keyword(s):  
Mechanical Properties ◽  
Optimization Problems ◽  
Comprehensive Evaluation ◽  
Relative Elongation ◽  
Weighted Average ◽  
Bending Rigidity ◽  
Elongation At Break ◽  
Lamination Process ◽  
Weighted Optimization ◽  
Generalized Utility

In order to ensure a comprehensive evaluation of laminated seams in working clothing, a series of research was carried out to determine the correlation between the parameters of the seam lamination process (i.e., the temperature, the time, the pressure) and the mechanical properties of laminated seams. The mechanical properties were defined by means of the maximum breaking force, the relative elongation at break and the total bending rigidity. The mechanical indexes were accepted as the measure of durability and stability of laminated seams. The correlation between the lamination process parameters and the final properties of the tested seams in working clothing was proposed using a three-factor plan 33. Finally, the single-criteria optimization was introduced and the objective functional is the generalized utility function U. Instead of three independent optimization problems, the single problem was applied, and the global objective function was a weighted average of partial criteria with the assumed weight values. The problem of multicriteria weighted optimization was solved using the determined weights and the ranges of acceptable/unacceptable values.

scholarly journals Hyperbranched polyamide modified graphene oxide-reinforced polyurethane nanocomposites with enhanced mechanical properties

RSC Advances ◽  
2021 ◽  
Vol 11 (24) ◽  
pp. 14484-14494
Author(s):  
Yahao Liu ◽  
Jian Zheng ◽  
Xiao Zhang ◽  
Yongqiang Du ◽  
Guibo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
High Performance ◽  
Cross Linking ◽  
Elongation At Break ◽  
Modified Graphene Oxide ◽  
High Performance Composite ◽  
Modified Graphene ◽  
Polyurethane Nanocomposites ◽  
Hyperbranched Polyamide

We successfully modified graphene oxide with amino-terminated hyperbranched polyamide (HGO), and obtained a high-performance composite with enhanced strength and elongation at break via cross-linking hydroxyl-terminated polybutadiene chains with HGO.

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