Effect of Alkali and Silane Treatment on the Thermal Stability of Hemp Fibers as Reinforcement in Composite Structures

2011 ◽  
Vol 415-417 ◽  
pp. 666-670 ◽  
Author(s):  
Na Lu ◽  
Shubhashini Oza ◽  
Ian Ferguson

Natural fiber reinforced composites are being used as reinforcement material in composite system due to their positive environmental benefits. Added to that, natural fibers offer advantages such as low density, low cost, good toughness, high specific strength, relatively non-abrasive and wide availability. However, the low thermal stability of natural fibers is one of the major challenges to increase their use as reinforcing component. In this study, a thorough investigation has been done to compare the effect of two chemical treatment methods on the thermal stability of hemp fibers. 5wt% sodium hydroxide and 5wt% triethoxyvinylsilane was used for the treatment of hemp fibers. Fourier transform infrared spectroscopy, scanning electron microscopy and thermo gravimetric analysis were used for characterization of untreated and treated fiber. The results indicated that 24 hours alkali treatment and 3 hours silane treatment time enhanced the thermal stability of the hemp fiber. However, alkali treatment shows better improvement compared to silane treatment.

2011 ◽  
Vol 71-78 ◽  
pp. 616-620 ◽  
Author(s):  
Na Lu ◽  
Shubhashini Oza

Hemp fiber is an excellent sustainable and renewable alternative to glass fiber as a reinforcing component in composite system, owing to its unique features of fast growth, high mechanical strength, low density, low cost, biodegradable, and low energy consumption. In this study a systematic investigation of physical and chemical treatment on hemp fiber was conducted, and their effects on thermal stability of hemp fiber were analyzed. Oxygen plasma treatment was used as physical modification approach, 5 wt% sodium hydroxide solution was used for chemical modification. Surface chemical composition and thermal stability were characterized by Fourier transform infrared spectroscopy and thermo gravimetric analysis. The results indicated that 5 wt% of NaOH with 16 hours treatment time increased hemp fiber thermal stability, while the plasma treatment had no impact on thermal stability of hemp fiber.


2020 ◽  
pp. 152808372092584
Author(s):  
Muhammad Awais Naeem ◽  
Qasim Siddiqui ◽  
Muhammad Rafique Khan ◽  
Muhammad Mushtaq ◽  
Muhammad Wasim ◽  
...  

In recent times, there is a growing demand for low-cost raw materials, renewable resources, and eco-friendly end products. Natural fibers are considered as strong candidates to be used as a potential reinforcement for composite manufacturing. In the current study, natural fibers extracted from banana peel were coated with bacterial cellulose through a green biosynthesis approach as well as by a simple slurry dipping method. Thus, natural fibers from banana peel waste were used the first time, to produce bacterial cellulose-natural fiber composites. SEM analysis revealed good interaction between the hybrid fibers and the epoxy matrix. Thermal gravimetric analysis results revealed that the degradation temperature increases because of the addition of bacterial cellulose on fiber surface, which improves the thermal stability. The maximum thermal decomposition temperature (405°C) was noticed for nanocomposites reinforced by banana fibers with bacterial cellulose deposited on their surface. Whereas the lowest weight loss was also found for the same sample group. The highest tensile strength (57.95 MPa) was found for SBC-BP/epoxy, followed by DBC-BP/epoxy (54.73 MPa) and NBP/epoxy (45.32 MPa) composites, respectively. Composites reinforced by both types of hybrid banana fibers shown comparatively higher tensile performance as compared with the neat banana peel fiber-epoxy composites, which can be attributed to the high strength and stiffness associated with the bacterial cellulose. Overall, this study suggests a successful and green route for the fabrication of natural fiber-reinforced composites with improved properties such as tensile strength and thermal stability.


2016 ◽  
Vol 857 ◽  
pp. 191-195 ◽  
Author(s):  
A. Nadiatul Husna ◽  
Bee Ying Lim ◽  
H. Salmah ◽  
Chun Hong Voon

Palm kernel shells (PKS) filled recycled high density polyethylene (rHDPE) biocomposites were produced using melt mixing. The biocomposites were prepared on Brabender Plasticorder at temperature of 185 °C and rotor speed of 50 rpm by varying filler loading (0 to 40 phr). In this study, the effect of PKS loading on rheological properties and thermal stability of rHDPE/PKS were investigated. Rheological study of the biocomposites was carried out by means of capillary rheometer under temperature of 190 °C, 200 °C and 210 °C. Thermal properties of biocomposites were studied by using thermo gravimetric analysis (TGA). The rheological results showed that the flowability of the composite increased with increasing temperature. Meanwhile, the result of TGA showed that at higher PKS loading, rHDPE/PKS biocomposites had lower total weight loss. The thermal stability of the biocomposites was reduced due to the addition of filler loading.


2011 ◽  
Vol 374-377 ◽  
pp. 1426-1429
Author(s):  
Xiao Meng Guo ◽  
Jian Qiang Li ◽  
Xian Sen Zeng ◽  
De Dao Hong

In this study, the thermal properties of a kind of new geotextile materials, so called controlled permeable formwork (CPF), were studied. Thermo-gravimetric analysis showed that the weight of CPF didn’t change much between 0~350 °C. Dynamic mechanical analysis showed that the storage modulus of CPF reduced from 25 MPa to around 10 MPa when the temperature rose to above 100 °C. The strength of sample decreased slightly with the increase of the temperature. The breaking elongation changed slightly with a maximum at 80 °C. The CPF showed excellent thermal stability and was suitable for general use in construction work.


2020 ◽  
Vol 54 (22) ◽  
pp. 3159-3169 ◽  
Author(s):  
Ezatollah (Nima) Amini ◽  
Mehdi Tajvidi

Utilization of cellulose nanocrystals as an additive in the formulation of biocomposites made with Acrodur® resin is presented. Natural fibers/polyethylene terephthalate mats were impregnated with Acrodur® and hot-pressed into the final thickness of 3 mm after drying. Biocomposites with 2 wt.% and 5 wt.% cellulose nanocrystal (dry-basis) were also produced. The produced biocomposite panels were then tested to determine the flexural strength, flexural modulus and Izod impact strength. The results revealed that adding cellulose nanocrystal to the composite formulation increased flexural modulus significantly up to 970 MPa (17.5% increase) at a panel density of 0.5 g/cm3, while it did not significantly affect flexural strength values. A slight reduction was observed in the impact strength of the samples by adding cellulose nanocrystal. The fractured samples of impact test were observed under a scanning electron microscope. It was shown that in all cases, the fracture happened due to the failure of the fibrous system and in particular natural fibers. Thermal stability of the composites was also investigated using thermo-gravimetric analysis. It was found that adding cellulose nanocrystal slightly reduced the thermal stability of the biocomposites. Potential compatibility of cellulose nanocrystal particles with Acrodur® resin is promising and the improvement in flexural modulus can lead to the design of lighter parts for automotive applications such as door panels, headliners, and underbody shields.


2013 ◽  
Vol 634-638 ◽  
pp. 1139-1142
Author(s):  
Mohamad Awang ◽  
Mohd Syahrizul Chik ◽  
Mustapha Rohani ◽  
Ali Noraaini

Utilization of locally abundant agro-waste Alpinia galanga (A. galanga) natural fibers in polyethylene (PE) was investigated. The results indicate that agro-waste fibers generally function as potential natural-organic fillers as well as show an attribute of reinforcement in PE-agro-waste composites at a certain fiber loading. Minimally reduced tensile strength from 28 MPa of unfilled PE, addition of agro-waste A. galanga natural fibers also resulted in reinforcement of up to 31 MPa at 6 wt% agro-waste fibers loading. Findings also reveal that alkali treatment was effective to impart surface modification of agro-waste A. galanga natural fibers and hence improved tensile strength, modulus of elasticity and thermal stability of PE-agro-waste composites.


2011 ◽  
Vol 45 (25) ◽  
pp. 2595-2601 ◽  
Author(s):  
Tsuyoshi Saotome ◽  
Ken Kokubo ◽  
Shogo Shirakawa ◽  
Takumi Oshima ◽  
H. Thomas Hahn

Novel nanocomposite films of polycarbonate (PC) with fullerene derivatives, such as pristine fullerene C60 and polyhydroxylated-fullerenes, C60(OH)12 and C60(OH)36, were prepared. The optical, thermal, and mechanical properties of the composites were measured. Nanocomposite films of poly (vinyl alcohol) (PVA) with C60(OH)36 were prepared as a reference to show how improved dispersion of the nanofiller affects the overall transparency of the composites. Ultraviolet-visible spectroscopy showed that the addition of hydroxylated fullerenes did not affect visible light transmittance of the films significantly in the range of 400–800 nm. Differential scanning calorimetry (DSC) and thermo–gravimetric analysis (TGA) measurements showed the increased thermal stability of PC/C60(OH)12 film as compared to pristine PC film. This phenomenon was explained by the rigid polymer interphase regions formed around C60(OH)12 due to the plausible hydrogen bonding and hydrophobic interaction. On the other hand, the lower thermal stability of PC–C60(OH)36 was assumed to be caused by large agglomeration of the C60(OH)36 particles and the partial hydrolysis of the polycarbonate matrix. Tensile testing of the composites showed reduction in elongation at break and yield tensile strength. These results may be caused by the particle agglomerations which act as the initiation points for cracks.


2021 ◽  
pp. 002199832199910
Author(s):  
Y Ben Smail ◽  
A El Moumen ◽  
A Imad ◽  
F Lmai ◽  
M Ezahri

In the last two decades, an increasing interest has been observed for the use of natural fibers such as jute fibers in different applications. These fibers are characterized by their low cost and their availability. They are mainly used in fabric bag manufacturing. The objective of this paper is to study the effect of temperature on the mechanical properties of jute yarns. An experimental study was conducted at different temperatures (22 °C; 80 °C; 105 °C and 150 °C) for 24 h. Each degree was followed by tensile testing of the specimen. Besides, the thermo-gravimetric analysis (TGA) was used to investigate the effect of the temperature on the thermal stability and the thermal degradation of the jute fibers. In addition, the statistical analysis was performed using the method of two and three-parameter Weibull distribution to determine the spatial distribution of the properties. The results showed that there was a degradation of the mechanical properties of the jute yarns heated to high temperature compared to the raw yarns (considered as a specimen exposed to 22 °C). The tensile strain and the Young modulus failed by 36% and 13% respectively for the specimens heated at 150 °C and the failure kinematic of the jute fiber was affected by the temperature of heating. The TGA showed that the thermal stability of the jute yarns was affected by two factors: fibers drying and their changing temperatures.


2014 ◽  
Vol 6 (2) ◽  
pp. 1122-1134 ◽  
Author(s):  
Mokhtar Hemdan Abd El-Salam

Due to the light weight, high specific strength and non hazardous nature of bamboo fiber, it is preferred over synthetic fibers in composite materials for a wide range of applications such as automotive industry and including household sectors. As was noticed, little attention has been given to the effect of bamboo powder on the mechanical properties of rubber composites. Hence, an attempt has been made in this paper to the study the effect of loading and particle size of bamboo powder on the mechanical properties of EPDM composites. Thermo-gravimetric analysis (TGA) was carried out to study the thermal stability of composites. Results indicated that the thermal stability of EPDM was further improved with increasing in bamboo loading and decreasing in particle size. The stress- strain curves of the composites were studied and fitted according toOgden’s model. Mechanical parameters for the studied composites were improved with increasing bamboo loading. Besides, properties such as rupture stress, and internal friction were found to be maximum for composites containing certain content of bamboo powder, depending upon its particle size. Moreover, composites containing the smallest particle size of powder, at all levels of bamboo loading, showed mechanical properties superior to all other composites. From the dynamic mechanical measurements, the dynamic modulus, internal friction, and thermal diffusivity were calculated. The observed variations were explained in view of the role played by both the loading level and the particle size of bamboo powder. These findings were supported by scanning electron microscopy (SEM) micrographs.


2019 ◽  
Vol 809 ◽  
pp. 433-438 ◽  
Author(s):  
Natalie Vellguth ◽  
Tanja Rudeck ◽  
Madina Shamsuyeva ◽  
Franz Renz ◽  
Hans Josef Endres

An effective integration of natural fibers into engineering thermoplastics requires sufficient thermal stability of natural fibers during processing, since melting temperature of engineering thermoplastics lies above 200 °C. The aim of the work was to protect natural fibers from the heat of the molten thermoplastic via coating with a modified epoxy resin, thus enabling manufacture of natural fiber-reinforced engineering thermoplastic composites with minimized thermal degradation of the fibers. Processing temperature comprised the range of engineering thermoplastic polyamide 6 (PA6), which was 225 °C. Flax fabrics were spray coated with partially bio-based epoxy resin and incorporated via hot press technique into a PA6 matrix. The composite samples including spray coated flax fibers as well as the reference flax fibers without coating were characterized with regard to their mechanical properties, namely bending and tensile tests, thermal properties with differential scanning calorimetry (DSC) as well as thermogravimetric analysis (TGA) and optical via scanning electron microscopy (SEM) and computer tomography (CT). The results show that this approach enables manufacture of composites with reproducible mechanical properties, i.e. bending and tensile properties as well as enhanced thermal stabilities.


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