scholarly journals Effect of Alkaline Treatment on Mechanical and Thermal Properties Oftypha Angustifolia Fiber Reinforced Composites

Author(s):  
M. Dedeepya ◽  
T.Dharma Raju ◽  
T. Jayananda Kumar

Sustainable development is increasingly becoming a priority of governments and businered which is driven by growing environmental awareness. Much academic research explores new ways to create greener and environmentally friendlier materials for variety of aplications ranging from aeronautic, automotive and construction industry. The natural fibre reinforced composite has the advantage of being light weight, availability, strong, cheap, safe, ease of recycling, sustainability, renewability hermal and acoustic insulation, saving of fabrication energy and carbon dioxide neutrality. The composites are molded with unsaturated polyester resin matrix and reinforced with natural fibre. Five identical specimens are prepared for each fibre content. In this study, mechanical properties of composite such as tensile strength, tensile modulus were measured using universal testing machine. Guarded hot plate apparatus was used to measure the thermal conductivity of natural fibre typha angustifolia reinforced composite.. The results shows that mechanical properties, increased as fiber content increased. Thermal conductivity of composite is in the range of 0.168 w/m k to 0.187 w/m k and thermal conductivity decreased about 11.3% as fiber content increased. The newly developed composite material has lower thermal conductivity and is used as an insulating material to save energy.

2009 ◽  
Vol 79-82 ◽  
pp. 2027-2030 ◽  
Author(s):  
Poonsub Threepopnatkul ◽  
Chanin Kulsetthanchalee ◽  
K. Bunmee ◽  
N. Kliaklom ◽  
W. Roddouyboon

This research was to study the related mechanical and thermal properties of recycled polypropylene from post consumer containers reinforced with coir fiber. Surface of coir fiber was treated with sodium hydroxide to remove lignin and hemicelluloses and likely to improve the interfacial adhesion in the composites. The composites of treated coir fiber and recycled polypropylene were prepared by varying the coir fiber contents at 5%, 10% and 20% by weight using a twin screw extruder. The thermal properties were investigated by thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC). The results from TGA showed that thermal stability of the composites was lower than that of recycled polypropylene resin and thermal stability decreased with increasing coir fiber content. From DSC results, it indicated that the crystallinity of treated coir fiber composites increased as a function of fiber content. The mechanical properties of injection-molded samples were studied by universal testing machine. The treated coir fiber composites produced enhanced mechanical properties. The tensile strength, tensile modulus and impact strength of modified coir fiber/recycled polypropylene composites increased as a function of coir fiber content.


2020 ◽  
Vol 38 (3B) ◽  
pp. 104-114
Author(s):  
Samah M. Hussein

This research has been done by reinforcing the matrix (unsaturated polyester) resin with natural material (date palm fiber (DPF)). The fibers were exposure to alkali treatment before reinforcement. The samples have been prepared by using hand lay-up technique with fiber volume fraction of (10%, 20% and 30%). After preparation of the mechanical and physical properties have been studied such as, compression, flexural, impact strength, thermal conductivity, Dielectric constant and dielectric strength. The polyester composite reinforced with date palm fiber at volume fraction (10% and 20%) has good mechanical properties rather than pure unsaturated polyester material, while the composite reinforced with 30% Vf present poor mechanical properties. Thermal conductivity results indicated insulator composite behavior. The effect of present fiber polar group induces of decreasing in dielectric strength, and increasing dielectric constant. The reinforcement composite 20% Vf showed the best results in mechanical, thermal and electrical properties.


2021 ◽  
pp. 51305
Author(s):  
Nora Abigail Wilson García ◽  
Jorge Luis Almaral Sánchez ◽  
Ramón Álvaro Vargas Ortiz ◽  
Abel Hurtado Macías ◽  
Nelly Flores Ramírez ◽  
...  

2009 ◽  
Vol 79-82 ◽  
pp. 553-556 ◽  
Author(s):  
Ling Fei Shi ◽  
Gang Li ◽  
Gang Sui ◽  
Xiao Ping Yang

The increasing proliferation and application of advanced polymer composites requires higher and broader performance resin matrices. Poly(oxypropylene) with –NH2 end-groups has been widely used to toughen epoxy resins, but the strength of resin matrix may be reduced due to the addition of flexible segments in the crosslinking network. Carbon nanotubes (CNTs) have been paid more and more attention in recent years because of their superior thermal and mechanical properties. In this paper, CNTs grafted with Jeffamines T403 were used to simultaneously improve the reinforcement and toughening of an epoxy resin. The untreated multi-walled carbon nanotubes (u-MWNTs) were functionalized with amine groups according to three steps: carboxylation, acylation, and amidation. The f-MWNTs were characterized by Fourier transform infra-red (FTIR) and X-ray photoelectron spectroscopy (XPS). The experimental results indicated that the T403 was grafted to the surface of MWCNTs. The mechanical and thermal properties of epoxy with f-MWNTs were investigated. The tensile and flexural strength increased by 7.77 % and 7.03 % after adding 0.5wt% f-MWCNTs without sacrificing the impact toughness. At the same time, dynamic mechanical thermal analysis (DMTA) showed that the glass transition temperature (Tg) of epoxy with f-MWNTs were increased. The fracture surface of epoxy with f-MWNTs was observed by scanning electron microscopy (SEM) to understand the dispersion of f-MWNTs in epoxy matrix and interfacial adhesion between f-MWNTs and epoxy matrix, which can be attributed to the strong interfacial bonding between f-MWNTs and epoxy resin.


2020 ◽  
Vol 1 (3) ◽  
pp. 77-83

Phenol novolac epoxy resin is a polymer matter which its properties can be modified for industrial needs. In this research, nanocomposites of phenol novolac epoxy resin and unsaturated polyester are made nano Bentonite and silica nanoparticles as filler. For this purpose, effect of nanoparticles percent on nanocomposite formation is studied and their physical, mechanical and thermal properties are obtained. The presence of unsaturated polyester in this process forms a cross-link capable of improving the physical and mechanical properties of epoxy resin. Fracture behavior was determined by a SEM device. Moreover, TGA, DSC, impact tests and bending test were applied for data analysis. When process ability is growing, moisture absorption decreases. Fracture toughness was also evaluated in a stoichiometric network. Physical and mechanical properties improve significantly with increasing nanoparticles. The most important reason for using this nanocomposite is its high resistance to corrosion.


2020 ◽  
Vol 18 (11) ◽  
pp. 801-805
Author(s):  
Kyung-Soo Jeon ◽  
R. Nirmala ◽  
Seong-Hwa Hong ◽  
Yong-II Chung ◽  
R. Navamathavan ◽  
...  

This manuscript is dealt with the synthesis of short carbon fibers reinforced polycarbonate polymer composite by using injection modeling technique. Four different composite materials were obtained by varying the carbon fibers weight percentage of 10, 20, 30 and 40%. The synthesized carbon fibers/polycarbonate composites were characterized for their morphological, mechanical and thermal properties by means of scanning electron microscopy (SEM), universal testing machine (UTM) and IZOD strength test. The resultant carbon fibers/polycarbonate composites exhibited excellent interfacial adhesion between carbon fibers and polycarbonate resin. The tensile properties were observed to be monotonically increases with increasing carbon fiber content in the composite resin. The tensile strength of carbon fiber/polycarbonate composites with the carbon fiber content 40% were increased about 8 times than that of the pristine polycarbonate matrix. The carbon fibers/polycarbonate composites with 40 wt.% of short carbon fibers exhibited a high tensile strength and thermal conductivity. The incorporation of carbon fiber in to polycarbonate resin resulted in a significant enhancement in the mechanical and the thermal behavior. These studies suggested that the short carbon fiber incorporated polycarbonate composite matrix is a good candidate material for many technological applications.


Author(s):  
Viola Hospodarova ◽  
Nadezda Stevulova ◽  
Vojtech Vaclavik ◽  
Tomas Dvorsky ◽  
Jaroslav Briancin

Nowadays, construction sector is focusing in developing sustainable, green and eco-friendly building materials. Natural fibre is growingly being used in composite materials. This paper provides utilization of cellulose fibres as reinforcing agent into cement composites/plasters. Provided cellulosic fibres coming from various sources as bleached wood pulp and recycled waste paper fibres. Differences between cellulosic fibres are given by their physical characterization, chemical composition and SEM micrographs. Physical and mechanical properties of fibre-cement composites with fibre contents 0.2; 0.3and 0.5% by weight of filler and binder were investigated. Reference sample without fibres was also produced. The aim of this work is to investigate the effects of cellulose fibres on the final properties (density, water absorbability, coefficient of thermal conductivity and compressive strength) of the fibrecement plasters after 28 days of hardening. Testing of plasters with varying amount of cellulose fibres (0.2, 0.3 and 0.5 wt. %) has shown that the resulting physical and mechanical properties depend on the amount, the nature and structure of the used fibres. Linear dependences of compressive strength and thermal conductivity on density for plasters with cellulosic fibres adding were observed.


2014 ◽  
Vol 27 (2) ◽  
pp. 77-82 ◽  
Author(s):  
H Ahmad ◽  
MA Islam ◽  
MF Uddin

Chopped jute fiber-epoxy composites with varying fiber length (2-12 mm) and mass fraction (0.05-0.35) had been prepared by a heat press unit. The cross-linked product was characterized in terms of specific gravity, thermal conductivity, tensile strength, Young modulus and elongation at break. The transverse thermal conductivities for randomly oriented fibers in the composite were investigated by Lees and Charlton’s method. The tensile strength, Young modulus and elongation at break were investigated by a Universal Tensile Tester. With an increase in the fiber content (irrespective of the fiber length), the thermal conductivity of the composite decreases; the decreasing rate being highest for the fiber length of 2 mm followed by that for the fiber length of 6 and 12 mm. The decreasing rate of the thermal conductivity of the jute-epoxy composite is comparatively higher to that reported in literature for acrylic polymer hemp fiber composite. The tensile strength also decreases with the increase of the fiber content in the composite. The fiber length does not show to have significant effect on the tensile strength of the composite; the variation in strength being masked within experimental error. The Young modulus increases with the increase of fiber content within elastic limit; showing the highest values for the fiber length of 6 mm followed by those for the fiber length of 2 mm and 12 mm. The elongation at break shows slightly increasing trend up to 15% fiber content, but beyond that it decreases drastically. The specific gravity decreases with the increase in the fiber content and thus the recalculated specific tensile strength is found to keep at a stable level of 36MPa up to the fiber content of 20%, and beyond that the specific tensile strength decreases with the increase in the fiber content. It is concluded that jute fiber-epoxy composite could be used as a good heat-insulating material. Further investigation is recommended on the improvement of the thermal insulation keeping the mechanical properties unchanged or even improved. The TGA study is also required to ascertain the field of application of the material. DOI: http://dx.doi.org/10.3329/jce.v27i2.17807 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 2, December 2012: 77-82


2015 ◽  
Vol 665 ◽  
pp. 217-220
Author(s):  
Ji Ze Mao ◽  
Hong Wei Zhang ◽  
Jian Fu Lv ◽  
Dao Guang Jia ◽  
Shi Kai Ao

Steel corrosion is one of the main problems of concrete structure durability. Compared with the steel, GFRP rebar has the advantages of high strength, low density and good corrosion resistance. Therefore, GFRP becomes a good choice to replace steel bar in concrete structure. Since GFRP material is susceptible to the alkaline conditions, it is necessary to clarify the mechanical properties and corrosion mechanism of GFRP rebar in such an alkaline environment of interior concrete. In this study, the artificial accelerated corrosion tests of two kinds of GFRP rebar (epoxy and unsaturated polyester resin matrix) were conducted at 60 °C in alkaline solution up to 90 days. Then the tensile strength tests of GFRP rebar were carried out. The solution PH values, the tensile strength and mass loss of GFRP rebar were measured. The testing results show that the mass of GFRP rebar had rarely changed, but the tensile strength reduced about 30% after 90-day immersion test in alkaline solution. During the test, the PH value of the alkaline solution decreased from 13.62 to around 12.85, which indicated that the hydroxyl ions of the alkaline solution had been consumed. The ester bonds in resin matrix may hydrolyze in alkaline solution and the bonding interface between fiber and resin can be damaged progressively. It can cause the performance degradation of GFRP rebar. In addition, the relationship between the loss of tensile strength and the reduction of PH can be determined. That means the durability of GFRP rebar in concrete can be enhanced by controlling or limiting the alkalinity when producing concrete. Finally, the GFRP rebar of epoxy resin matrix shows higher retention values of tensile strength and better alkali resistance than those of UPR matrix rebar after 90d immersion in the alkaline solution. The obtained results in this paper can provide application reference of GFRP materials in civil engineering.


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