Effect of water absorption on mechanical and tribological properties of Indian ramie/epoxy composites

Author(s):  
Rajiv Kumar ◽  
Mir I Ul Haq ◽  
Sanjay M Sharma ◽  
Ankush Raina ◽  
Ankush Anand

In the present work, the water absorption behaviour of Indian ramie/epoxy composites and its effect on mechanical and tribological behaviour have been investigated. The composites fabricated using the hand layup technique were immersed in distilled water at room temperature for water absorption test for a period of 120 days. Mechanical and tribological properties were evaluated for composites with 30 wt.% ramie fibre loading. The results obtained were compared with that of the dry specimen. Mechanical properties including tensile strength, flexural strength, impact strength and hardness were evaluated. A reduction of 16.85%, 13.63%, 21.02% and 3.33% in tensile strength, flexural strength, impact strength and hardness was observed after the water immersion, respectively. Friction and wear behaviour was also investigated for water immersed specimen. Frictional coefficient decreased for the developed composites and wear performance reduced after the water absorption test. Fractured surfaces post to mechanical testing and worn out surfaces of tribological test samples were examined by scanning electron microscopy. The weakening of fibre–matrix interface was observed in the scanning electron microscopy micrographs, which appears to be the main cause for the degradation of properties.

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Li Juan

The nanocomposites of polypropylene (PP)/graphene were prepared by melt blending. The effects of the dosage of graphene on the flow and mechanical properties of the nanocomposites were investigated. The morphologies of fracture surfaces were characterized through scanning electron microscopy (SEM). The graphene simultaneous enhanced tensile and impact properties of nanocomposites. A 3.22% increase in tensile strength, 39.8% increase in elongation at break, and 26.7% increase in impact strength are achieved by addition of only 1 wt.% of graphene loading. The morphological behavior indicates the fracture surface of PP/graphene is more rough than that of pure PP.


2015 ◽  
Vol 4 (3) ◽  
pp. 23-28
Author(s):  
Fadhilla Asyri ◽  
Kartini Noor Hafni ◽  
A. Haris Simamora

This study aims was to determine the effect of palm oil fuel ash (POFA) composite as filler on the physical and mechanical properties of high impact polystyrene (HIPS) composites. The research methodology included preparation of raw materials, treatment POFA (hydration process of POFA), mixing using tumbler and then extruder, molding composite specimens, and testing. The variables used were weight ratio of HIPS with 140 mesh POFA at 95/5; 92.5/7.5; 90/10. The composites were tested by Fourier Transform Infrared (FTIR), ash content, specific gravity, tensile strength, elongation at break, impact strength, hardness test, and Scanning Electron Microscopy (SEM). The results of FTIR characterization shows the formation of –OH bonding that was suspected as Si-OH or Si-hydrat. Results of physical and mechanical properties of the composites shows that increase of the filler composition in HIPS-POFA composites until the ratio of 90/10, increase the specific gravity to 7.2% of the original, tensile strength did not change significantly to 28.4 MPa, elongation at break decreased to 2.7%, impact strength decreased to 3.183 KJ/m2, and the hardness increased to 110.5, and Scanning Electron Microscopy (SEM) test show the transformation of POFA structure on treated POFA and intercalation between the matrix and POFA.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.


2018 ◽  
Vol 186 ◽  
pp. 02001
Author(s):  
Teng-wei Zhu ◽  
Cheng-liang Miao ◽  
Zheng Cheng ◽  
Zhipeng Wang ◽  
Yang Cui ◽  
...  

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.


2011 ◽  
Vol 194-196 ◽  
pp. 1740-1744 ◽  
Author(s):  
Qiu Hong Wang ◽  
Gu Huang

Flax fabric was woven and composites were produced by using the VARI technique with flax fabric as the reinforcement and unsaturated polyester as the matrix. Laminates with two, three and four layers were fabricated respectively. After saturated in the water for different durations of time (7, 14, 21 and 30 days), the tensile strength of the composites was tested. After being soaked in the water for 7, 14 and 21 days, the tensile strength of the two-layer composites was decreased. For the three and four layers specimens, the tensile strength was increased initially with water treatment for 7 and 14 days,and decreased for 21 and 30 days. Scanning electron microscopy (SEM) confirmed that it might be contributed to the thickness of the two-layer composites. The thinner specimen is easier to be damaged by the penetrated moisture owing to the delamination between the fiber and the matrix after water immersion. For the three and four layers specimens, their contradictory tensile strength suggests that the thicker specimen can delay the moisture permeation and is of better water durability.


2019 ◽  
Vol 33 (11) ◽  
pp. 1466-1477
Author(s):  
Qingfa Zhang ◽  
Wenyu Lu ◽  
Liang Zhou ◽  
Donghong Zhang ◽  
Hongzhen Cai ◽  
...  

Biocomposites were prepared with corn straw slagging (CSS) and high-density polyethylene (HDPE) at four loading levels (10, 20, 30, and 40 wt%) by extrusion method. CSS/HDPE composites were tested by tension, oxygen index meter, differential scanning calorimetry, X-ray diffraction, and the scanning electron microscopy. The scanning electron microscopy showed that CSS was dispersed uniformly in the HDPE matrix and strong interfacial interaction was achieved, which had an important influence on the tensile strength of the composites. The tensile strength of the composites could be improved with proper increase of CSS and reached maximum value at 30 wt% content. Furthermore, the addition of CSS played an important role in improving the flame-retardant ability of CSS/HDPE composites, and the limited oxygen index was 31.26% at 40 wt% content, good flame-retardant effect achieved.


2019 ◽  
Vol 815 ◽  
pp. 139-144
Author(s):  
Tao Mu

In this paper, acrylic acid was grafted to chitosan in order to change the structure; polymer was obtained from modified chitosan. A series of novel toughened composite NF memebranes were prepared by over-coating the polysulfone ultrafiltration membrane with the polymer of modified chitosan. The chitosan derivatives and the polymer were characterised by infrared spectrophotometer (IR); the structure of the membrane was characrerised by scanning electron microscopy (SEM) and atomic force microscope (AFM). The composite NF membrane’s performances were strictly related to the structure of polymer. The rejection of the membrane was 96.3% with flux as high as 386.46 L m-2 h-1 with the 1000 mg/L of NaCl. Tensile strength of membrane increased 46%. The HCl (5%) resistance increased from 20.3 to 36.8h. The NaOH (5%) resistance increased from 18.3 to 31.6h. These results indicated the prepared toughened composite NF memebrane was excellent NF membrane, which had a wide application prospect.


2020 ◽  
Vol 861 ◽  
pp. 378-382
Author(s):  
Sophoan Phal ◽  
Muhammad Rafiullah Khan ◽  
Pattarin Leelaphiwat ◽  
Vanee Chonhenchob

Sodium alginate based films containing turmeric oil (TEO) at different concentrations (1, 2 and 3%) were developed. The film with no TEO was used as control. Incorporation of TEO had the effects on the film properties. With increasing TEO concentrations, thickness, elongation at break, permeability of oxygen and water vapor of the films significantly (p ≤ 0.05) increased. Whereas moisture content, tensile strength and modulus of elasticity significantly (p ≤ 0.05) decreased. Scanning electron microscopy (SEM) analysis showed more numerous pores and rougher surface of the antifungal films than the control film.


2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lokesh R. Rane ◽  
Niranjan R. Savadekar ◽  
Pravin G. Kadam ◽  
Shashank T. Mhaske

The purpose of this study is to improve the performance properties of K-carrageenan (K-CRG) by utilizing nanosilica (NSI) as the reinforcing agent. The composite films were prepared by solution casting method. NSI was added up to 1.5% in the K-CRG matrix. The prepared films were characterized for mechanical (tensile strength, tensile modulus, and elongation at break), thermal (differential scanning calorimetry, thermogravimetric analysis), barrier (water vapour transmission rate), morphological (scanning electron microscopy), contact angle, and crystallinity properties. Tensile strength, tensile modulus, and crystallinity were found to have increased by 13.8, 15, and 48% whereas water vapour transmission rate was found to have decreased by 48% for 0.5% NSI loaded K-CRG composite films. NSI was found to have formed aggregates for concentrations above 0.5% as confirmed by scanning electron microscopy. Melting temperature, enthalpy of melting, and degradation temperature of K-CRG increased with increase in concentration of NSI in K-CRG. Contact angle also increased with increase in concentration of NSI in K-CRG, indicating the decrease in hydrophilicity of the films improving its water resistance properties. This knowledge of the composite film could make beneficial contributions to the food and pharmaceutical packaging applications.


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