scholarly journals Comparison of the Thermal and Electrical Conductivities of Pretreated Kenaf–Polyester Composites

2021 ◽  
Vol 6 (6) ◽  
pp. 65-68
Author(s):  
P. U. N. Obianuko ◽  
J. C. Obianuko ◽  
T. U. Onuegbu
Keyword(s):  
Unsaturated Polyester ◽  
Physical Property ◽  
Appreciable Effect ◽  
Fibre Composites ◽  
Electrical Conductivities ◽  
Engineering Designs ◽  
Naoh Solution ◽  
Chemical Pretreatments ◽  
Kenaf Bast ◽  
Thermal Conductivities

Conductivity of a material is an important physical property that determines its suitability or otherwise in all engineering designs and construction. The aim of this study is to determine the effects of two pretreatment methods viz acetylation and permanganate on the thermal and electrical conductivities of pretreated kenaf bast fibres applied in polyester resin. Fully grown kenaf (hibiscus cannabalis) were manually retted from the stalk, washed, and cut into short fibre lengths of about 10 cm. One portion of the fibres was pretreated with 5%pbw NaOH solution before immersing it in glacial acetic acid and then in acetic anhydride. The second was also pretreated with5%pbw of NaOH before being pretreated with 0.125%of KMnO4. The third portion of fibres was untreated to serve as control. The ground fibre was incorporated into ortho unsaturated polyester rand cast with moulds of dumb-belland square shapes. The electrical conductivity of the composites was deduced by measuring the resistance of the composites using the high voltage insulation tester model 3122 and calculating from equations. The thermal conductivities were determined by analytical method. The results show that chemical pretreatments of fibres by acetylation and permanganate methods have no appreciable effect on the thermal conductivities of composites. Further findings show that the acetylated fibre composites have no effect on the electrical conductivities of the composites. The permanganate pretreated fibre composites however increased the electrical conductivities of the composites significantly.

Manufacture of Sheets Using Post-Consumer Unsaturated Polyester Resin/Glass Fibre Composites

2002 ◽  
Vol 18 (2) ◽  
pp. 111-125 ◽  
Author(s):  
A. G. Pedroso ◽  
D. S. Rosa ◽  
T. D. Z. Atvars
Keyword(s):  
Glass Fibre ◽  
Polyester Resin ◽  
Unsaturated Polyester ◽  
Impact Resistance ◽  
Weight Ratio ◽  
High Volume ◽  
Volume Weight ◽  
Fibre Composites ◽  
Powdered Composite ◽  
Resin Curing

The storage of post-consumer unsaturated polyester/glass fibre composites impacts negatively on the environment due to its persistence (long lifetime of both the glass fibre and the resin) as well as the high volume/weight ratio of the residues. In this work we introduce a new approach for the recycling process of artefacts made of these polyester/glass fibre composites that involves the dispersion of the ground, not powdered, composite in raw polyester resin. Room temperature resin curing was employed. Flexural and impact tests were performed to optimize the processing conditions and the manufacturing process. Significant improvement in texture, flexural strength and impact resistance of sheets were achieved by pressing and heating the sheets at 40∞C and 50∞C during curing. The artefacts utilized in our work were post-consumer public telephone weather protector caps, which, in Brazil, are manufactured with a composite of unsaturated polyester/glass fibre. Although we used this specific artefact, the methodology can be extended to different types of post-consumer materials or industrial scraps.

Hybrid epoxy composites made from treated curauá fibres and organophilic clay

2020 ◽  
Vol 55 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Gilberto García del Pino ◽  
Abderrezak Bezazi ◽  
Haithem Boumediri ◽  
Antonio Claudio Kieling ◽  
Cláudia Cândida Silva ◽  
...  
Keyword(s):  
Hybrid Composites ◽  
Impact Resistance ◽  
Tensile Modulus ◽  
X Ray Diffraction ◽  
Three Point Bending ◽  
Epoxy Polymers ◽  
Fibre Composites ◽  
Nano Clay ◽  
Naoh Solution ◽  
Organophilic Clay

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.

The influence of fibre orientation and chemical treatment on the performance of unsaturated polyester/chrysanthemum stem fibre composites

2020 ◽  
pp. 096739112095406
Author(s):  
Maydul Islam ◽  
Chan Ming Yeng ◽  
Koay Seong Chun ◽  
Ho Shuh Huey
Keyword(s):  
Tensile Properties ◽  
Water Resistance ◽  
Research Study ◽  
Fibre Orientation ◽  
Unsaturated Polyester ◽  
Agricultural Waste ◽  
Elongation At Break ◽  
Fibre Composites ◽  
The Impact ◽  
Bleaching Treatment

Chrysanthemum flowers are usually used for cultural and religious ceremonies however, the chrysanthemum stems are left for open burning or landfilling on many farmlands. These stems are one of the sources of agricultural waste in Malaysia that cause environmental impacts. In order to reduce the impact of chrysanthemum stems, this research study has utilised these valuable chrysanthemum stems in producing a new polymer composite. Hence, the present research study focuses on the preparation of non-woven and woven chrysanthemum stem fibre (CSF) reinforced unsaturated polyester (UPs) composites via simple hand lay-up method. The results showed the tensile properties (tensile strength and modulus of elasticity) of woven fibre filled UPs was higher than non-woven fibre filled UPs composites. However, non-woven fibre filled UPs presented higher water absorption and elongation at break as compared to woven fibre filled UPs composites. Furthermore, bleaching treatment with hydrogen peroxide is carried out in order to improve the tensile properties and water resistance of UPs/CSF composites. The functional groups of unbleached and bleached fibres were analysed using Fourier Transform Infrared (FTIR) analysis. Some lignin, hemicellulose and impurities of CSF have been removed after the bleaching treatment on CSF, as proven by FTIR results.

scholarly journals The Influence of MMA Esterification on Interfacial Adhesion and Mechanical Properties of Hybrid Kenaf Bast/Glass Fiber Reinforced Unsaturated Polyester Composites

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2276
Author(s):  
Rozyanty Rahman ◽  
Syed Zhafer Firdaus Syed Putra ◽  
Shayfull Zamree Abd Rahim ◽  
Irwana Nainggolan ◽  
Bartłomiej Jeż ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Glass Fiber ◽  
Interfacial Adhesion ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Unsaturated Polyester ◽  
Research Work ◽  
Tensile Fracture ◽  
Kenaf Bast

The demand for natural fiber hybrid composites for various applications has increased, which is leading to more research being conducted on natural fiber hybrid composites due to their promising mechanical properties. However, the incompatibility of natural fiber with polymer matrix limits the performance of the natural fiber hybrid composite. In this research work, the mechanical properties and fiber-to-matrix interfacial adhesion were investigated. The efficiency of methyl methacrylate (MMA)-esterification treatments on composites’ final product performance was determined. The composite was prepared using the hand lay-up method with varying kenaf bast fiber (KBF) contents of 10, 15, 20, 25, 30, 35 (weight%) and hybridized with glass fiber (GF) at 5 and 10 (weight%). Unsaturated polyester (UPE) resin and methyl ethyl ketone peroxide (MEKP) were used as binders and catalysts, respectively. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to examine the effects of MMA-esterification treatment on tensile strength and morphology (tensile fracture and characterization of MMA-esterification treatment) of the composite fabricated. The tensile strength of MMA-treated reinforced UPE and hybrid composites are higher than that of untreated composites. As for MMA treatment, 90 min of treatment showed the highest weight percent gain (WPG) and tensile strength of KBF-reinforced UPE composites. It can be concluded that the esterification of MMA on the KBF can lead to better mechanical properties and adhesion between the KFB and the UPE matrix. This research provides a clear reference for developing hybrid natural fibers, thus contributing to the current field of knowledge related to GF composites, specifically in transportation diligences due to their properties of being lightweight, superior, and involving low production cost.

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