scholarly journals Effect of Hemp Fibre Surface Treatment on the Fibre-Matrix Interface and the Influence of Cellulose, Hemicellulose, and Lignin Contents on Composite Strength Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Mohammad Mazedul Kabir ◽  
Mohammad Yousef Alhaik ◽  
Saud Hamad Aldajah ◽  
Kin Tak Lau ◽  
Hao Wang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Fibre Surface ◽  
Optical Microscope ◽  
Strength Properties ◽  
Interfacial Bonding ◽  
Natural Fibres ◽  
Attractive Alternative ◽  
Scanning Calorimetry ◽  
Bonding Properties

Natural fibres have recently become an attractive alternative to synthetic fibres in the implementation of polymer composite structures. Inherent flaws within natural fibres in terms of their constituent contents (hemicellulose, cellulose, and lignin) reduce the compatibility of these fibres with polymer matrices. In this study, the effects of chemical treatments on hemp fibres and the resulted polyester matrix composite are investigated. The fibres were treated with alkali (0–10% NaOH), acetyl, and silane chemicals. Long unidirectional fibre composites were prepared by vacuum-assisted resin transfer moulding (VARTM) process. Thermal properties of the fibres were tested using differential scanning calorimetry (DSC) analyses. The mechanical properties of the composite samples were tested using compression and bending tests. Failure analysis of tested composites was undertaken through Optical Microscope (OM) and Scanning Electron Microscope (SEM). The results showed that the treatments of the 4% NaOH reduced interfacial bonding strength and decreased composite properties compared to untreated samples. At higher concentrations (6–10% NaOH), the mechanical properties of the composites increased as a result of greater interfacial bonding. Different trends were observed in the case of alkalised fibres that were further treated with acetyl and silane treatments. It was observed that the treated fibres effectively improved the bonding properties of composites and was in agreement with the micrographs.

scholarly journals The effect of isothermal crystallization on mechanical properties of poly(ethylene 2,5-furandicarboxylate)

e-Polymers ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 1-11
Author(s):  
Wei Zhang ◽  
Qingyin Wang ◽  
Gongying Wang ◽  
Shaoying Liu
Keyword(s):  
Mechanical Properties ◽  
Intrinsic Viscosity ◽  
Crystallization Temperature ◽  
Isothermal Crystallization ◽  
Tensile Modulus ◽  
Optical Microscope ◽  
Crystallization Time ◽  
Scanning Calorimetry ◽  
Crystallization Properties ◽  
Poly Ethylene

Abstract The effects of isothermal crystallization temperature/time on mechanical properties of bio-based polyester poly(ethylene 2,5-furandicarboxylate) (PEF) were investigated. The intrinsic viscosity, crystallization properties, thermal properties, and microstructure of PEF were characterized using ubbelohde viscometer, X-ray diffraction, polarizing optical microscope, differential scanning calorimetry, and scanning electron microscopy. The PEF sample isothermal crystallized at various temperatures for various times was denoted as PEF-T-t. The results showed that the isothermal crystallization temperature affected the mechanical properties of PEF-T-30 by simultaneously affecting its crystallization properties and intrinsic viscosity. The isothermal crystallization time only affected the crystallization properties of PEF-110-t. The crystallinity of PEF-110-40 was 17.1%. With small crystal size, poor regularity, and α′-crystal, PEF-110-40 can absorb the energy generated in the tensile process to the maximum extent. Therefore, the best mechanical properties can be obtained for PEF-110-40 with the tensile strength of 43.55 MPa, the tensile modulus of 1,296 MPa, and the elongation at a break of 13.36%.

scholarly journals Up-cycling of agave tequilana bagasse-fibres: A study on the effect of fibre-surface treatments on interfacial bonding and mechanical properties

2020 ◽  
Vol 8 ◽  
pp. 100158
Author(s):  
Omar Huerta-Cardoso ◽  
Isidro Durazo-Cardenas ◽  
Veronica Marchante-Rodriguez ◽  
Phil Longhurst ◽  
Frederic Coulon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fibre Surface ◽  
Surface Treatments ◽  
Interfacial Bonding ◽  
Agave Tequilana

The effect of hybrid nanoparticle with silica sol as the supporter on the crystallization behavior and mechanical properties of isotactic polypropylene

2015 ◽  
Vol 35 (6) ◽  
pp. 565-573 ◽  
Author(s):  
Juan Li ◽  
Shuhao Qin ◽  
Wentao He ◽  
Yushu Xiang ◽  
Qin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Isotactic Polypropylene ◽  
Crystallization Behavior ◽  
Optical Microscope ◽  
Silica Sol ◽  
Hybrid Nanoparticles ◽  
Hybrid Particles ◽  
Scanning Calorimetry ◽  
Chemical Action ◽  
Time Dynamic

Abstract Colloidal dispersions of hybrid nanoparticles with silica sol as the supporter (PKSol) were prepared by supporting aromatic phosphate on silica sol via a chemical action with γ-aminopropyltrimethylsilane (KH550) as a linker in wet process for the first time. Dynamic light scattering (DLS) demonstrated that hybrid nanoparticles with an average size of about 200 nm were formed and transmission electron microscopy (TEM) confirmed the presence of the ultrafine silica sols within the hybrid particles, which exhibited “currant-bun” particle morphologies, rather than typical “core-shell” structures for most polymer-encapsulated silica particles. Compared to aromatic phosphate alone and silane-modified silica sol, the effect of PKSol on the crystallization behavior and mechanical properties of isotactic polypropylene (iPP) was investigated using a polarized optical microscope (POM) and differential scanning calorimetry (DSC). The results demonstrated that PKSol showed superior nucleating ability on iPP than the other two. After adding 0.2 wt% PKSol, the crystallization peak temperature of iPP increased from 116.35°C to 120.81°C and the crystallinity increased from 39.6% to 50%. Correspondingly, the haze decreased from 37.6% to 23.3% and mechanical properties were improved.

Compatibilising additives for enhancing the interaction at the phase interface in thermoplastic vulcanisates based on rubbers of different polarity and polypropylene*

2018 ◽  
Vol 45 (7) ◽  
pp. 307-310
Author(s):  
O.A. Panfilova ◽  
S.I. Vol’fson ◽  
N.A. Okhotina ◽  
R.K. Sabirov ◽  
I.V. Baranets ◽  
...  
Keyword(s):  
Vinyl Acetate ◽  
Cooling System ◽  
Phase Interface ◽  
Optical Microscope ◽  
Strength Properties ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Experimental Conditions ◽  
Tensile Elastic Modulus ◽  
Distribution Of Components

The possibilities of increasing the interaction between the components of previously developed thermoplastic vulcanisates based on polypropylene and a combination of isoprene and nitrile butadiene rubbers were studied. The morphology of the composites was recorded by means of optical microscopy using an analytical complex based on a Leica DM-2500 optical microscope, a Leica DFC-420C digital high-resolution colour camera with a Peltier cooling system, and a specialised computer desk. The parameters of crystallisation of polypropylene were measured by differential scanning calorimetry using a DSC 204F1 Phoenix instrument (Netzsch). The physicomechanical properties of the vulcanisates were also determined. Maleinised polypropylene, a copolymer of ethylene with vinyl acetate, and their mixtures were used as compatibilising additives. Maleinised polypropylene was introduced together with polypropylene in a quantity of 1–10 parts; no changes in properties were observed with increase in the dosage above 4 parts, so this dosage was used. The copolymer of ethylene with vinyl acetate (1–10 parts) was introduced into the rubber phase at the stage of rubber mix preparation specially to improve the compatibility of polypropylene and nitrile butadiene rubber. The introduction of maleinised polypropylene leads to an increase in the workability and in the level of elastic strength properties, in particular the tensile elastic modulus and hardness. A considerable increase in the uniformity of distribution of components throughout the volume, a finer dispersion of the rubbers in the polypropylene matrix, and a reduction in the number of pores in the material were shown, and also an increase in the degree of polypropylene crystallinity measured under experimental conditions. The most positive effect is observed with the combined introduction of the copolymer of ethylene with vinyl acetate and the maleinised polypropylene: the nominal stress under elongation increases by 34%, and the elongation at break by 15%. The combined introduction of the compatibilising additives improves the compatibility of the components of the system, the phase boundaries become more diffuse, there is a reduction in the optical density of rubber-rich zones, and these zones are penetrated by polypropylene fibrils.

scholarly journals Effect of Intensive Cooling of Alloy AZ91 with a Chromium Addition on the Microstructure and Mechanical Properties of the Casting

2017 ◽  
Vol 62 (4) ◽  
pp. 2199-2204
Author(s):  
C. Rapiejko ◽  
B. Pisarek ◽  
T. Pacyniak
Keyword(s):  
Mechanical Properties ◽  
Thermal Effects ◽  
Room Temperature ◽  
Optical Microscope ◽  
Strength Properties ◽  
Chromium Addition ◽  
Alloy Az91 ◽  
Microstructure And Mechanical Properties ◽  
Kinetics And Dynamics ◽  
Made In

AbstractThe work presents the results of the investigations of the effect of intensive cooling of alloy AZ91 with an addition of chromium on the microstructure and mechanical properties of the obtained casts. The experimental castings were made in ceramic moulds preliminarily heated to 180°C, into which alloy AZ91 with the addition was poured. Within the implementation of the research, a comparison was made of the microstructure and mechanical properties of the castings obtained in ceramic moulds cooled at room temperature and the ones intensively cooled in a cooling liquid. The kinetics and dynamics as well as the thermal effects recorded by the TDA method were compared. Metallographic tests were performed with the use of an optical microscope and the strength properties of the obtained castings were examined: UTS (Rm), elongation (A%), and HB hardness.

Effect of Solution Treatment on Microstructure and Mechanical Properties of Hot-Extruded Cu-15Ni-8Sn Alloy

2017 ◽  
Vol 898 ◽  
pp. 1156-1162
Author(s):  
Xun Wang ◽  
Chao Zhao ◽  
Yan Gen Yu ◽  
Zong Qiang Luo ◽  
Wei Wen Zhang
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Solution Time ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Annealing Twins ◽  
Optimum Solution ◽  
Electronic Microscope

The effects of solution treatment on the microstructure evolution of hot-extruded Cu-15Ni-8Sn alloy were investigated by optical microscope (OM), scanning electronic microscope (SEM), differential scanning calorimetry (DSC) and tensile testing, and the effects of solution temperature and time on the mechanical properties of the alloys were analyzed. The results indicated that, the γ-phases precipitated at first and then dissolved with the extension of the solution time during solutionizing at 800 C,the volume fraction of theγ-phase reached its peak at about 1h. However when solutionizing at 860°C, theγ-phase solely dissolved gradually with the extension of the solution time . In addition, a small amount of annealing twins appeared intragranular in the process of solution treatment. The γ-phase dissolution and the grain growth of α (Cu) were the main softening factors of the alloy during the solution treatment. Through overall consideration, the optimum solution treatment was annealing at 840°Cfor 1 h.

Design and Processing of Novel Ceramic Composite Structures for Use in Medical Surgery

2017 ◽  
Vol 750 ◽  
pp. 195-204
Author(s):  
Marta Fornabaio ◽  
Paola Palmero ◽  
Helen Reveron ◽  
Jérôme Chevalier ◽  
Laura Montanaro
Keyword(s):  
Mechanical Properties ◽  
Composite Structures ◽  
Ceramic Composite ◽  
Optical Microscope ◽  
Medical Surgery ◽  
Composite Powders ◽  
Bending Tests ◽  
Nanostructured Composite ◽  
Second Phases ◽  
Dental Applications

. In order to fulfill the clinical requirements for strong, tough and stable ceramics for dental applications, we have designed and developed innovative Ceria-stabilized zirconia (Ce-TZP)-based composites. In particular, we have added two kinds of second phases to the Ce-TZP matrix: equiaxed a-Al2O3 grains, for increasing the hardness and the fracture strength, and elongated hexa-aluminates (both SrAl12O19 and CeMgAl11O19), to provide an additional toughening effect by crack deflection/bridging mechanisms. In order to carefully control the composition and the microstructure in those complex composite systems, we have used a novel surface-coating approach for the preparation of the nanostructured composite powders, which allows a perfect tailoring of the microstructural, morphological and compositional features of the composites. Once optimized the sintering cycle for each composite material, both composites reached full densification. Mechanical properties (Vickers hardness, flexural strength and fracture toughness) were evaluated, while the zirconia transformability was followed by means of an optical microscope during load-unload bending tests. The sensitivity to ageing was estimated by autoclave treatments. In spite of a remarkable different behavior – mainly in terms of stress-induced tetragonal to monoclinic zirconia transformability - both materials showed excellent mechanical properties as well as a negligible sensitivity to ageing, thus demonstrating their high potential for new reliable and safe devices for structural biomedical applications.

scholarly journals Effect of Fiber Reinforcement on the Compression and Flexural Strength of Fiber-Reinforced Geopolymers

2021 ◽  
Vol 11 (21) ◽  
pp. 10443
Author(s):  
Michał Łach ◽  
Bartłomiej Kluska ◽  
Damian Janus ◽  
Dawid Kabat ◽  
Kinga Pławecka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Building Materials ◽  
Bending Strength ◽  
Strength Properties ◽  
Attractive Alternative ◽  
Reinforcing Fibers ◽  
Different Types ◽  
The Matrix ◽  
Glass Carbon

This work aimed to determine the effect of the addition of different types of reinforcing fibers on the strength properties of geopolymers such as flexural and compressive strength. Geopolymers are an attractive alternative to conventional binders and building materials; however, one of the main problems of their widespread use is their low resistance to brittle fracture. To improve the mechanical properties, reinforcement in the form of glass, carbon, and basalt fibers (as grids) was applied to geopolymers in the following work. Additionally, composites with these fibers were produced not only in the matrix of pure geopolymer but also as a hybrid variant with the addition of cement. Furthermore, basalt grids were used as reinforcement for geopolymers not only based on ash but also metakaolin. An additional variable used in the study was the molar concentration of the alkali solution (5 M and 10 M) for the different types of geopolymer samples. The mechanical properties of geopolymer materials and geopolymer–cement hybrids are the highest when reinforcement in the form of carbon fiber is used. Strength values for geopolymers reinforced with basalt mats depend on the number of reinforcement layers and the concentration of the alkaline solution used. All produced composites were tested for compressive strength and bending strength. When using basalt mesh, it was possible to achieve a bending strength of 12 MPa. The highest compressive strength that was achieved was the value of 66 MPa, while for samples not reinforced with fibers, only about 40 MPa was achieved.

Effect of post-treatment on the microstructure and mechanical properties of selective laser melted Ti6Al4V lattice structures

2020 ◽  
Vol 26 (9) ◽  
pp. 1569-1577
Author(s):  
Xina Huang ◽  
Lihui Lang ◽  
Shuili Gong ◽  
Mali Zhao
Keyword(s):  
Mechanical Properties ◽  
Hot Isostatic Pressing ◽  
Optical Microscope ◽  
Post Treatment ◽  
Lattice Structures ◽  
Electron Backscattered Diffraction ◽  
Scanning Calorimetry ◽  
Content Type ◽  
Treatment Processes ◽  
Number Of Cycles

Purpose The purpose of this paper is to investigate the post-treatment processes on lattice structures of selective laser melting. Moreover, the effect of pressure during hot isostatic pressing (HIP) is determined. Design/methodology/approach Three post-treatment processes, annealing at 650°C, 920°C and HIP were adopted. The microstructure evolution and mechanical properties of selective lasering melted Ti6Al4V lattice structures after post-treatment were systematically investigated by optical microscope, scanning electron microscope, electron backscattered diffraction, differential scanning calorimetry and quasi-static mechanics tests. Findings The main findings in this paper are as below: first, the pores existing in the samples as-fabricated, annealed at 650°C and 920°C are disappeared after HIP. Second, the microstructure and compressive properties after HIP are similar to that after pure annealing at the same temperature. However, the HIPed sample had the highest number of cycles to failure. Third, the fracture mechanism of as-fabricated samples changes from mixed fracture to the micro-voids accumulation fracture after post-treatment processes. Originality/value HIP post-treatment can be replaced by annealing at the same temperature when the requirement for porosity and fatigue life is not very high.

scholarly journals Study on microstructure and mechanical properties of P92 steel after high-temperature long-term aging at 650°C

2020 ◽  
Vol 39 (1) ◽  
pp. 545-555
Author(s):  
Peng Duan ◽  
Zongde Liu ◽  
Bin Li ◽  
Jiayao Li ◽  
Xiangqian Tao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Optical Microscope ◽  
Strength Properties ◽  
Continuous Precipitation ◽  
P92 Steel ◽  
Aging Period ◽  
High Temperature Mechanical Properties ◽  
Early Aging

AbstractA series of long-term high-temperature aging tests of ASME A335-P92 steel from 1,000 to 29,000 h at 650°C were carried out. The microstructure evolution of as-received and aging specimens at different stages was investigated using optical microscope observations, scanning electron microscope examinations, and TEM investigations. The static mechanical strength properties (yield strength/ultimate tensile strength) at room and 600°C test temperatures and the plastic performance (elongation/reduction in area) were also analyzed. The experimental results show that the Laves phase can be precipitated rapidly in the early aging period. After a certain aging period, the continuous precipitation of M23C6 and the relatively high coarsening rate of Laves resulted in a rapid decrease of room and high-temperature mechanical properties in the early aging period. However afterwards for the long aging time, a slow decline in tendency of mechanical properties was presented.

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