scholarly journals Effects of Fiber Surface Grafting with Nano-Clay on the Hydrothermal Ageing Behaviors of Flax Fiber/Epoxy Composite Plates

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1278 ◽  
Author(s):  
Wang ◽  
Xian ◽  
Li

Flax fiber has high sensitivity to moisture, and moisture uptake leads to the decrease of mechanical properties and distortion in shape. This paper attempts to graft flax fabric with nano-clay, with assistance from a silane-coupling agent, in order to improve hygrothermal resistance. The nano-clay grafted flax fabric reinforced epoxy (FFRP) composite produced through vacuum assisted resin infusion (VARI) process were subjected to 80% RH chamber for 12 weeks at 20, 40 and 70 °C, respectively. Moisture uptake, dimensional stability, and tensile properties was studied as a function of humidity exposure. Through SEM and FTIR, the effects of hygrothermal exposure was elucidated. In comparison to control FFRP plates, nano-clay grafting decreases saturation moisture uptake and the coefficient of diffusion of FFRP by 38.4% and 13.2%, respectively. After exposure for six weeks, the retention rate of the tensile modulus of the nano-clay grafted flax fiber based FFRP increased by 33.8% compared with that of the control ones. Nano-clay grafting also reduces the linear moisture expansion coefficient of FFRPs by 8.4% in a radial direction and 10.9% in a weft direction.

Author(s):  
Hossein Kazemi ◽  
Frej Mighri ◽  
Keun Wan Park ◽  
Slim Frikha ◽  
Denis Rodrigue

ABSTRACT In recent years, cellulose fibers have attracted considerable attention as biofillers for natural rubber (NR) composites. However, neat cellulose cannot be used as a substitute for conventional fillers due to its poor compatibility with NR. Therefore, a new surface treatment via maleic anhydride grafted to polyisoprene (MAPI) in solution was developed to improve the filler–matrix interaction. Different contents of carbon black (CB) and cellulose fibers (before and after modification) were used as a hybrid filler system to investigate the possibility of CB substitution in NR composites. First, contact angle, Fourier transformed infrared spectrometry (FTIR), and scanning electron microscopy (SEM) techniques were used to confirm the successful cellulose surface treatment. Second, morphological analysis, Payne effect, and swelling behavior of the rubber compounds in toluene confirmed the effect of cellulose treatment on improving the interfacial filler–matrix adhesion. Finally, the results showed that the composite filled with 20 phr modified cellulose and 20 phr CB (50% replacement of CB) exhibited even better results than the composite filled with 40 phr of CB, since the tensile strength was only 7% lower, but the elongation at break, tensile modulus at 100%, and storage modulus at 25 °C were respectively 35%, 24%, and 22% higher.


2020 ◽  
Vol 55 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Gilberto García del Pino ◽  
Abderrezak Bezazi ◽  
Haithem Boumediri ◽  
Antonio Claudio Kieling ◽  
Cláudia Cândida Silva ◽  
...  

This work evaluates an epoxy composite reinforced with curauá fibres and/or organophilic clay. Epoxy polymers reinforced with nano-clays are also assessed. Composites are manufactured by cold pressing using fibres in pristine and treated conditions. Three levels of the factors NaOH solution (2.5, 5 and 10%) and immersion time (2, 4 and 10 hours) are investigated. Nano-clays are incorporated at the levels of 2.5, 5 and 10 wt.%. The morphology and crystallinity of the treated fibres are evaluated by scanning electron microscopy and X-ray diffraction, respectively. Tensile, three-point bending and impact tests are performed to characterise the composites. Tensile strength, flexural strength and impact resistance are increased by 24%, 44% and 47%, respectively, when compared to untreated fibre composites. The highest tensile and flexural strengths are achieved by hybrid composites containing 5 wt.% of nano-clay and 20 wt.% of curauá fibres treated with 5% NaOH for 4 hours. In contrast, the highest tensile modulus is achieved when hybrid composites are made from untreated fibres and 10 wt.% of nanoparticles. The highest impact resistance is obtained by curauá composites, without particles, composed of fibres treated with 5% NaOH for 4 hours. The inclusion of nano-clay leads to reduced impact resistance values.


2018 ◽  
Vol 8 (7) ◽  
pp. 1172 ◽  
Author(s):  
Nunzio Cennamo ◽  
Luigi Zeni ◽  
Ester Catalano ◽  
Francesco Arcadio ◽  
Aldo Minardo

In this paper, we show that light-diffusing fibers (LDF) can be efficiently used as host material for surface plasmon resonance (SPR)-based refractive index sensing. This novel platform does not require a chemical procedure to remove the cladding or enhance the evanescent field, which is expected to give better reproducibility of the sensing interface. The SPR sensor has been realized by first removing the cladding with a simple mechanical stripper, and then covering the unclad fiber surface with a thin gold film. The tests have been carried out using water–glycerin mixtures with refractive indices ranging from 1.332 to 1.394. The experimental results reveal a high sensitivity of the SPR wavelength to the outer medium’s refractive index, with values ranging from ~1500 to ~4000 nm/RIU in the analyzed range. The results suggest that the proposed optical fiber sensor platform could be used in biochemical applications.


Fibers ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 83 ◽  
Author(s):  
Ozgun Guzdemir ◽  
Amod A. Ogale

Polypropylene (PP) fibers are heavily used in disposable nonwovens fabrics because of their desirable properties and low-cost, but they are not biodegradable. With the goal of reducing non-biodegradable plastic waste in the environment, the primary aim of this study was to produce fibers with reduced content of PP for disposable fabrics by incorporating soy flour, a bio-based renewable material. An optimum processing temperature of 190 °C was established, and thin fibers with a diameter under 60 µm were successfully melt-spun. Inclusion of compatibilized soy (SFM) at 30 wt% resulted in fibers with a tensile modulus of 674 ± 245 MPa and a yield strength of 18 ± 4 MPa. At 15 wt% SFM, fiber tensile modulus and yield strength were 914 ± 164 and 29 ± 3, respectively. Although lower than those of neat PP fibers (1224 ± 136 MPa and 37 ± 3 MPa), these SFM/PP fiber properties are suitable for nonwoven applications. Additionally, partial presence of soy particulates on fiber surface imparted enhanced water absorption and colorability properties to the fibers while imparting the fibers the feel of natural fibers.Although more difficult to produce, soy-PP fibers possessed similar properties as compared to those of than soy-PE fibers reported in earlier studies.


e-Polymers ◽  
2015 ◽  
Vol 15 (3) ◽  
pp. 169-177 ◽  
Author(s):  
Anil Arya ◽  
Jose E. Tomlal ◽  
George Gejo ◽  
Joseph Kuruvilla

AbstractEco-friendly bio-composite of polypropylene (PP)/coir-sisal blended yarn was prepared using commingling technique, in which both the fibers are wound onto a metal plate and then compression molded. Various chemical treatments have been done in order to improve the interfacial adhesion between the matrix and reinforcement, thereby to increase the properties of the composite. Thermal stability study was done using thermogravimetric analysis. The resulting thermogram reveals that chemical treatments increase the thermal stability of the commingled composite to a considerable extent. A significant increase is observed in the tensile properties of the treated composite especially maleic anhydride modified PP (MAPP) treated composite as compared to the untreated one. The tensile strength and tensile modulus of MAPP treated composite was found to be 29.24 MPa and 1330 MPa, respectively, which was found to be 7.5% and 6.4% greater than that of untreated composite. The experimentally observed tensile properties of the composites were compared with the existing models of reinforced composites. The surface morphology and fiber surface treatments were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy.


Author(s):  
James J.-S. Stone ◽  
Shen-Haw Ju ◽  
Robert E. Rowlands

The frictional contact of the pin-loaded joint in composite plates was studied. This included the effects of pin clearance and variations in material and geometry. Full-filed displacements were measured by high sensitivity moire´ interferometry. Considerable effort was expended to develop a loading frame, relevant fixtures and monitoring capability to ensure that the plate was loaded uniformly through its thickness, particularly at the pin-loaded hole. Numerical techniques were prepared for processing the optical fringe data. A reliable finite element model for a bolted joint was also formulated. The efficient finite element program, which is capable of handling friction and/or clearance at the loaded hole, has been validated analytically, experimentally and numerically.


2021 ◽  
Author(s):  
Meiling Jia ◽  
Chenghan Yi ◽  
Yankun Han ◽  
Xin Li ◽  
Guoliang Xu ◽  
...  

Abstract Thin, lightweight, and flexible textile pressure sensors with the ability to precisely detect the full range of faint pressure (< 100 Pa), low pressure (in the range of KPa) and high pressure (in the range of MPa) are in significant demand to meet the requirements for applications in daily activities and more meaningfully in some harsh environments, such as high temperature and high pressure. However, it is still a major challenge to fulfill these requirements simultaneously in a single pressure sensor. Herein, a high-performance pressure sensor enabled by polyimide fiber fabric with functionalized carbon-nanotube (PI/FCNT) is obtained via a facile electrophoretic deposition (EPD) approach. High-density FCNT is evenly wrapped and chemically bonded to the fiber surface during the EPD process, forming a conductive hierarchical fiber/FCNT matrix. Benefiting from the abundant yet firm contacting points, point-to-point contacting mode, and high elastic modulus of both PI and CNT, the proposed PI/FCNT pressure sensor exhibits ultra-high sensitivity (3.57 MPa− 1), ultra-wide linearity (3.24 MPa), exceptionally broad sensing range (~ 45 MPa), and long-term stability (> 4000 cycles). Furthermore, under a high working temperature of 200 ºC, the proposed sensor device still shows an ultra-high sensitivity of 2.64 MPa− 1 within a wide linear range of 7.2 MPa, attributing to its intrinsic high-temperature-resistant properties of PI and CNT. Thanks to these merits, the proposed PI/FCNT(EPD) pressure sensor could serve as an E-skin device to monitor the human physiological information, precisely detect tiny and extremely high pressure, and can be integrated into an intelligent mechanical hand to detect the contact force under high-temperature (> 300 ºC), endowing it with high applicability in the fields of real-time health monitoring, intelligent robots, and harsh environments.


2022 ◽  
Vol 58 (4) ◽  
pp. 171-178
Author(s):  
Elangovan Kasi ◽  
Mohan Ramakrishnan

The usage of seals in several applications like aircraft engines is mostly made of Fluorocarbon (FKM) elastomer. They are coloured products that enable easier identification based on the applications. In such seals, fillers like carbon black cannot be added to reinforce and improvise the mechanical properties since carbon black does not make it possible to add colours. The properties after ageing are also very critical in sealing application, and they must also be improved. Also, Nanocomposites are the modern and growing trends in the field of polymers that show enormous changes in the properties of the polymers without affecting their basic properties. So, the need for improvisation of FKM seals and the concept of Nanocomposites can be merged to form FKM Nanocomposites with Nano clay and Nano silica as the fillers. The objective of this project is to improve the mechanical properties, better retention of properties after ageing and after fluid interaction of the FKM seals with the aid of Nanofillers. Different proportions of FKM nanocomposites were prepared using modified Nano Kaolin Clay & modified Montmorillonite clay (Cloisite grades). Various mechanical properties like tensile strength, tensile modulus, elongation at break, compression set and tear strength etc., were studied. The test results have shown good improvements while increasing the filler loading. This is helpful to manufacture seals of desired colours thereby avoiding the difficulties faced in the carbon black-filled FKM compounds.


2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Jinshu Shi ◽  
Sheldon Q. Shi ◽  
H. Michael Barnes ◽  
Mark F. Horstemeyer ◽  
Ge Wang

The objective of this study was to investigate an inorganic nanoparticle impregnation (INI) technique to improve the compatibility between kenaf bast fibers and polyolefin matrices. The Scanning Electron Microscopy (SEM) was used to examine the surface morphology of the INI-treated fibers showing that the CaCO3nanoparticle crystals grew onto the fiber surface. Energy-dispersive X-ray spectroscopy (EDS) was used to verify the CaCO3nanoparticle deposits on the fiber surface. The tension tests of the individual fiber were conducted, and the results showed that the tensile strength of the fibers increased significantly (more than 20%) after the INI treatments. Polymer composites were fabricated using the INI-treated fiber as reinforcement and polypropylene (PP) as the matrix. The results showed that the INI treatments improved the compatibility between kenaf fibers and PP matrix. The tensile modulus and tensile strength of the composites reinforced with INI-treated fibers increased by 25.9% and 10.4%, respectively, compared to those reinforced with untreated kenaf fibers.


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