The Experts below are selected from a list of 3411 Experts worldwide ranked by ideXlab platform

Na Lu - One of the best experts on this subject based on the ideXlab platform.

Shubhashini Oza - One of the best experts on this subject based on the ideXlab platform.

  • effect of surface treatment on thermal stability of the Hemp pla composites correlation of activation energy with thermal degradation
    Composites Part B-engineering, 2014
    Co-Authors: Shubhashini Oza, Haibin Ning, Ian T Ferguson
    Abstract:

    Abstract The thermal behavior of Hemp-poly lactic acid composites with both untreated and chemically surface modified Hemp Fiber was characterized by means of activation energy of thermal degradation. Three chemical surface modification employed were; alkali, silane and acetic anhydride. Model-free isoconversion Flynn–Wall–Ozawa method was chosen to evaluate the activation energy of composites. The results indicated that composites prepared with acetic anhydride modified Hemp had 10–13% higher activation energy compared to other composites. Further, among the three surface modifications, acetic anhydride resulted in higher activation energy (159–163 kJ/mol). Fourier transform infrared spectroscopy supported the findings of thermogravimetric analysis results, wherein surface functionalization changes were observed as a result of surface modification of Hemp Fiber. It was concluded that, higher bond energy results in higher activation energy, which improves thermal stability. The activation energy data can aid in better understanding of the thermal degradation behavior of composites as a function of composite processing.

  • a comparative study of the mechanical properties of Hemp Fiber with virgin and recycled high density polyethylene matrix
    Composites Part B-engineering, 2013
    Co-Authors: Shubhashini Oza
    Abstract:

    Abstract Hemp reinforced composites were prepared using both recycled high density polyethylene (rHDPE) and virgin high density polyethylene (vHDPE). The effects of Fiber loading and the different type of matrix on the composites’ mechanical and thermo-mechanical properties were studied. Prior to composite fabrication, Hemp Fibers were treated with 5 wt% NaOH. The change in surface morphology and chemical composition of Hemp Fibers after treatment was analyzed by scanning electron microscope and Fourier transform infrared spectroscopy. Findings indicate that a 5 wt% NaOH treatment effectively improved the Fiber–matrix interface resulting in improved mechanical properties. With respect to both, mechanical and thermo-mechanical properties, Hemp Fiber composites with rHDPE matrix performed better than composites with vHDPE matrix. The optimized Fiber loading of Hemp–rHDPE was 40% volume fraction while achieving the highest tensile strength of 60.2 MPa and flexural strength of 44.6 MPa. The Hemp–rHDPE composites with 30% of Fiber loading demonstrated the best impact strength of 51.1 KJ/m2.

  • thermal and mechanical properties of recycled high density polyethylene Hemp Fiber composites
    2011
    Co-Authors: Shubhashini Oza, Ruoyang Wang, Wang Yanan, Na Lu
    Abstract:

    Implementation of “green laws” in several countries hasgeneratedrenewed research interest in natural Fiber reinforced composites in different industrial sectors such as automotive, construction, building and electrical. In this study, we have investigated the effect of chemical treatment of Hemp Fiber on thermal and mechanical properties of Hemp Fiber composites with recycled high density polyethylene matrix. The chemical composition effect on thesurface modification wasanalyzed by means ofFourier transform infrared spectroscopy (FTIR) and the thermal stability of composites properties were studied bythermo gravimetric analysis (TGA). The mechanical properties of the composites were testedin accordance to ASTM D790 with Fiber volume fractions in the range of 20-40%. The results showed that the chemical treatment of Hemp Fiber improved the thermal stability of the Fiber. The maximum flexural strength of Hemp Fiber composites of 44.6MPa was observed with the composite containing 40% Fiber volume fraction.

Mohini Sain - One of the best experts on this subject based on the ideXlab platform.

  • studies on the water absorption properties of short Hemp glass Fiber hybrid polypropylene composites
    Journal of Composite Materials, 2007
    Co-Authors: Suhara Panthapulakkal, Mohini Sain
    Abstract:

    Hemp Fiber is one of the inexpensive and readily available bast natural Fibers and Hemp-Fiber reinforced polymer composite products have gained considerable attraction for automotive interior products. Though extensive research has been made on the performance evaluation of these composite materials, not much data is available on the moisture absorption of the composites, which restricts their use in exterior applications. This study aims to investigate the moisture absorption of short Hemp Fiber and Hemp-glass hybrid reinforced thermoplastic composites to study their suitability in outdoor applications. The water absorption properties and its effect on the tensile properties of Hemp and Hemp/glass Fiber hybrid polypropylene (PP) composites prepared by an injection molding process were investigated. Effect of hybridization on the water uptake and the kinetics of moisture absorption of the Hemp Fiber composites were evaluated by immersing the hybrid composite samples in distilled water at different tempera...

  • measurement and prediction of thermal conductivity for Hemp Fiber reinforced composites
    Polymer Engineering and Science, 2007
    Co-Authors: Tayebeh Behzad, Mohini Sain
    Abstract:

    The thermal conductivity of Hemp Fiber reinforced polymer composites were studied from the steady state temperature drop across samples exposed to a known heat flux. The transverse and in-plane thermal conductivities for oriented and randomly oriented composites for different volume fractions of Fiber were investigated. Experimental results showed that the orientation of Fibers has a significant effect on the thermal conductivity of composites. To validate the experimental results, the heating tests for the thermal conductivity measurements were simulated by a finite element model using the thermal conductivity values obtained from the experiments. Predicted temperatures show close agreement with measured temperatures. Moreover, the experimental results of thermal conductivities of composites at different directions were compared with two theoretical models and illustrated good agreement between the obtained results and models. POLYM. ENG. SCI. 47:977–983, 2007. © 2007 Society of Plastics Engineers

  • finite element modeling of polymer curing in natural Fiber reinforced composites
    Composites Science and Technology, 2007
    Co-Authors: Tayebeh Behzad, Mohini Sain
    Abstract:

    Plant-based Fibers have been selected as suitable reinforcements for composites due to their good mechanical performances and environmental advantages. This paper describes the development of a simulation procedure to predict the temperature profile and the curing behavior of the Hemp Fiber/thermoset composite during the molding process. The governing equations for the non-linear transient heat transfer and the resin cure kinetics were presented. A general purpose multiphysics finite element package was employed. The procedure was applied to simulate one-dimensional and three-dimensional models. Experiments were carried out to verify the simulated results. Experimental data shows that the simulation procedure is numerically valid and stable, and it can provide reasonably accurate predictions. The numerical simulation was performed for a three-dimensional complex geometry of an automotive part to predict the temperature distribution and the curing behavior of the composite during the molding process.

  • injection molded short Hemp Fiber glass Fiber reinforced polypropylene hybrid composites mechanical water absorption and thermal properties
    Journal of Applied Polymer Science, 2007
    Co-Authors: Suhara Panthapulakkal, Mohini Sain
    Abstract:

    Natural Fiber-based thermoplastic composites are generally lower in strength performance compared to thermoset composites. However, they have the advantage of design flexibility and recycling possibilities. Hybridization with small amounts of synthetic Fibers makes these natural Fiber composites more suitable for technical applications such as automotive interior parts. Hemp Fiber is one of the important lignocellulosic bast Fiber and has been used as reinforcement for industrial applications. This study focused on the performance of injection-molded short Hemp Fiber and Hemp/glass Fiber hybrid polypropylene composites. Results showed that hybridization with glass Fiber enhanced the performance properties. A value of 101 MPa for flexural strength and 5.5 GPa for the flexural modulus is achieved from a hybrid composite containing 25 wt % of Hemp and 15 wt % of glass. Notched Izod impact strength of the hybrid composites exhibited great enhancement (34%). Analysis of Fiber length distribution in the composite and fracture surface was performed to study the Fiber breakage and fracture mechanism. Thermal properties and resistance to water absorption properties of the Hemp Fiber composites were improved by hybridization with glass Fibers. Overall studies indicated that the short Hemp/glass Fiber hybrid polypropylene composites are promising candidates for structural applications where high stiffness and thermal resistance is required. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2432–2441, 2007

  • Study of Structural Morphology of Hemp Fiber from the Micro to the Nanoscale
    Applied Composite Materials, 2007
    Co-Authors: Bei Wang, Mohini Sain, Kristiina Oksman
    Abstract:

    The focus of this work has been to study how high pressure defibrillation and chemical purification affect the Hemp Fiber morphology from micro to nanoscale. Microscopy techniques, chemical analysis and X-ray diffraction were used to study the structure and properties of the prepared micro and nanoFibers. Microscopy studies showed that the used individualization processes lead to a unique morphology of interconnected web-like structure of Hemp Fibers. The nanoFibers are bundles of cellulose Fibers of widths ranging between 30 and 100 nm and estimated lengths of several micrometers. The chemical analysis showed that selective chemical treatments increased the α-cellulose content of Hemp nanoFibers from 75 to 94%. Fourier transform infrared spectroscopy (FTIR) study showed that the pectins were partially removed during the individualization treatments. X-ray analysis showed that the relative crystallinity of the studied Fibers increased after each stage of chemical and mechanical treatments. It was also observed that the Hemp nanoFibers had an increased crystallinity of 71 from 57% of untreated Hemp Fibers.

Lawrence T Drzal - One of the best experts on this subject based on the ideXlab platform.

  • effect of Fiber surface treatment on the properties of biocomposites from nonwoven industrial Hemp Fiber mats and unsaturated polyester resin
    Journal of Applied Polymer Science, 2006
    Co-Authors: Geeta Mehta, Lawrence T Drzal, Amar K Mohanty, Manjusri Misra
    Abstract:

    Biocomposites were made with nonwoven Hemp mats and unsaturated polyester resin (UPE). The Hemp Fiber volume fraction was optimized by mechanical testing. The effect of four surface treatments of industrial Hemp Fibers on mechanical and thermal properties of biocomposites was studied. The treatments done were alkali treatment, silane treatment, UPE (matrix) treatment, and acrylonitrile treatment. Bending strength, modulus of elasticity, tensile strength, tensile modulus, impact strength, storage modulus, loss modulus, and tan δ were evaluated and compared for all composites. The mechanical as well as thermal properties of the biocomposites improved after surface treatments. The properties of the above biocomposites were also compared with E-glass–mat composite. To achieve balance in properties, a hybrid composite of industrial Hemp and glass Fibers was made. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1055–1068, 2006

  • Injection molded biocomposites from soy protein based bioplastic and short industrial Hemp Fiber
    Journal of Polymers and the Environment, 2005
    Co-Authors: Amar K Mohanty, P. V. Mulukutla, Manjursi Misra, Praveen Tummala, Wenhua Liu, Lawrence T Drzal
    Abstract:

    Biocomposites from soy based bioplastic and chopped industrial Hemp Fiber were fabricated using twin-screw extrusion and injection molding process. Soy based bioplastics were prepared through cooking with plasticizer and blending with biodegradable poly( ester amide). Mechanical, thermal properties and fracture surface morphology of the "green''/biocomposites were evaluated with universal testing system (UTS), dynamic mechanical analysis (DMA), Environmental Scanning Electron Microscopy (ESEM). It was found that the tensile strength and modulus, flexural strength and modulus, impact strength and heat deflection temperature of industrial Hemp Fiber reinforced biocomposites significantly improved. The fracture surfaces showed no signs of matrix on the Fiber surface suggesting poor interfacial adhesion.

  • effect of process engineering on the performance of natural Fiber reinforced cellulose acetate biocomposites
    Composites Part A-applied Science and Manufacturing, 2004
    Co-Authors: Amar K Mohanty, Arief C. Wibowo, Manjusri Misra, Lawrence T Drzal
    Abstract:

    Eco-friendly green/biocomposites were fabricated from chopped Hemp Fiber and cellulose ester biodegradable plastic through two process engineering approaches: powder impregnation through compression molding (process I) and extrusion followed by injection molding (process II). Cellulose ester, e.g. cellulose acetate (CA) plasticized with 30 wt% citrate plasticizer (CAP) was used as the matrix polymer for biocomposite fabrication. Intimate mixing due to shear forces experienced in process II produced superior strength biocomposites over their counterparts made using process I. Biocomposite fabricated through process II containing 30 wt% Hemp natural Fiber showed an improvement of storage modulus by 150% over the virgin matrix polymer. The coefficient of thermal expansion of the said biocomposite decreased from the CAP polymer by 60% whereas the heat deflection temperature improved by 30% versus the virgin bioplastic, indicating superior thermal behavior of the biocomposite. Plasticized cellulose acetate is proved to be much better matrix than non-polar polypropylene (PP) for Hemp Fiber (HF) reinforcements because of the better interaction of polar cellulose ester with the polar natural Fiber. Fabricated through process II and with same content of Hemp (30 wt%) the CAP-HF based biocomposite exhibited flexural strength of 78 MPa and modulus of elasticity of 5.6 GPa as contrast to 55 MPa and 3.7 GPa for the corresponding PP-HF based composite. The experimental findings of tensile modulus of the biocomposites are compared with the theoretical modulus using the rule of mixture. The Fiber-matrix adhesion is evaluated through environmental scanning electron microscopy studies.

Haibin Ning - One of the best experts on this subject based on the ideXlab platform.

  • Hemp Fiber reinforced polypropylene composites the effects of material treatments
    Composites Part B-engineering, 2017
    Co-Authors: Theresa Sullins, Selvum Pillay, Alastair Komus, Haibin Ning
    Abstract:

    Abstract Natural Fiber reinforced thermoplastic matrix composites have been increasingly used in semi-structural applications in automotive applications because of their good specific strength and modulus, low carbon footprint and recyclability. This research work studies the effects of material treatment(s) on the mechanical behaviors of Hemp Fiber reinforced polypropylene (PP) composites. The material treatment(s) are realized by chemically treating the Hemp Fiber with different concentration NaOH and/or adding maleic anhydride grafted polypropylene (MAPP) to the PP matrix. The purpose of the material treatment(s) is to enhance the bonding between the Hemp Fibers and the polypropylene matrix which otherwise has low surface energy and limited bonding. The mechanical behaviors are investigated with different combinations of material treatment(s) such as 5 wt% MAPP, 5% NaOH treated Hemp Fiber, 10% NaOH treated Hemp Fiber, and 5% NaOH + 5 wt% MAPP. 15 wt% and 30 wt% Hemp Fiber loadings are used in the composites with these material treatments. It is found that the material treatment(s) result(s) in composites with better mechanical properties compared to the composites without any treatment(s). The composites with 5 wt% MAPP addition show the best mechanical properties.

  • effect of surface treatment on thermal stability of the Hemp pla composites correlation of activation energy with thermal degradation
    Composites Part B-engineering, 2014
    Co-Authors: Shubhashini Oza, Haibin Ning, Ian T Ferguson
    Abstract:

    Abstract The thermal behavior of Hemp-poly lactic acid composites with both untreated and chemically surface modified Hemp Fiber was characterized by means of activation energy of thermal degradation. Three chemical surface modification employed were; alkali, silane and acetic anhydride. Model-free isoconversion Flynn–Wall–Ozawa method was chosen to evaluate the activation energy of composites. The results indicated that composites prepared with acetic anhydride modified Hemp had 10–13% higher activation energy compared to other composites. Further, among the three surface modifications, acetic anhydride resulted in higher activation energy (159–163 kJ/mol). Fourier transform infrared spectroscopy supported the findings of thermogravimetric analysis results, wherein surface functionalization changes were observed as a result of surface modification of Hemp Fiber. It was concluded that, higher bond energy results in higher activation energy, which improves thermal stability. The activation energy data can aid in better understanding of the thermal degradation behavior of composites as a function of composite processing.