The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

G M Pharr - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of interphase properties in a Cellulose Fiber reinforced polypropylene composite by nanoindentation and finite element analysis
    Composites Part A-applied Science and Manufacturing, 2007
    Co-Authors: Seunghwan Lee, G M Pharr, Siqun Wang
    Abstract:

    Abstract The hardness and elastic modulus of the Cellulose Fiber and polypropylene (PP) matrix in a Cellulose Fiber-reinforced PP composite were investigated by nanoindentation with a continuous stiffness technique. Nanoindentation with different indentation depths and spacings was conducted to measure hardness and elastic modulus in the interphase region, which was modified by maleic anhydride-grafted PP and γ-amino propyltrimethoxy silane (γ-APS) sizing. A line of indents was produced from the Fiber to the matrix. There was a gradient of hardness and modulus across the interphase region. The distinct properties of the transition zone were revealed by 1–4 indents, depending on nanoindentation depth and spacing. Based on the results of nanoindentation, it was assumed that the width of the property transition zone is less than 1 μm. However, three dimensional finite element analysis shows that even a perfect interface without property transition has almost same interphase width as that measured by nanoindentation. Using existing nanoindentation techniques, it will be difficult to calculate exact mechanical properties without the effect of neighboring material property in at least 8 times smaller region than indent size.

Kristiina Oksman - One of the best experts on this subject based on the ideXlab platform.

  • One-step twin-screw extrusion process of Cellulose Fibers and hydroxyethyl Cellulose to produce fibrillated Cellulose biocomposite
    Cellulose, 2020
    Co-Authors: Hesam Taheri, Maiju Hietala, Kristiina Oksman
    Abstract:

    In this work, the defibrillation of Cellulose Fibers (CF) in the presence of hydroxyethyl Cellulose (HEC) within the one-step twin-screw extrusion (TSE) process was examined. The effect of the TSE on Cellulose Fiber size reduction as well as CF-HEC biocomposites properties were investigated. The results showed that the TSE of Cellulose Fiber-hydroxyethyl Cellulose (CF-HEC) with different Cellulose Fiber contents (50, 65, and 80 wt%) resulted in partial defibrillation of the Cellulose Fibers. The fractionation test of the Cellulose Fibers confirmed that their size was reduced and some fibrillation was observed in microscopy studies. The maximum width reduction of 46% occurred with 80 wt% Cellulose content. However, the partial width reduction was also observed with 50% and 65 wt% of Cellulose contents. Based on rheological measurements, the shear-viscosity trend of CF-HEC dispersion abruptly dropped when higher Fiber content (80 wt%) was extruded, which was related to the fibrillation of the Cellulose Fibers as well as the reduction of the length. The extruded CF-HEC materials (powder form) were compression molded to prepare the biocomposites with different Cellulose Fiber contents (50, 65, and 80 wt%). The extruded CF-HEC powders were diluted with addition extra HEC to make biocomposites with lower Fiber content (20%, 30%, and 40 wt%) and compression molded to study how the size reduction of the Cellulose Fibers affected the mechanical properties of biocomposites. The results showed that the E-modulus improved from 0.4 GPa of the neat HEC to 1.6 GPa for the composite with 40 wt% CF. Interestingly, the tensile strength of CF-HEC biocomposite with 40 wt% confirmed a clear improvement from 9.8 to 26.6 MPa, confirming good interaction between HEC and CF. Graphic abstract Preparation (mixing, TSE, and hot-pressing) and characterization (FE-SEM, rheometry, and tensile test) of CF-HEC biocomposite

Girish M Ganjyal - One of the best experts on this subject based on the ideXlab platform.

  • impacts of Cellulose Fiber particle size and starch type on expansion during extrusion processing
    Journal of Food Science, 2017
    Co-Authors: Sravya Kallu, Ryan J Kowalski, Girish M Ganjyal
    Abstract:

    Objective of this study was to understand the impacts of Cellulose Fiber with different particle size distributions, and starches with different molecular weights, on the expansion of direct expanded products. Fiber with 3 different particle size distributions (<125, 150 to 250, 300 to 425 μm) and 4 types of starches representing different amylose contents (0%, 23%, 50%, and 70%) were investigated. Feed moisture content (18 ± 0.5 % w.b) and extruder temperature (140 °C) were kept constant and only the extruder screw speed was varied (100, 175, and 250 rpm) to achieve different specific mechanical energy inputs. Fiber particle size and starch type significantly influenced the various product parameters. In general, the smaller Fiber particle size resulted in extrudate with higher expansion ratio. Starch with an amylose: amylopectin ratio of 23:77 resulted in highest expansion compared to the other starches, when no Fiber was added. Interestingly, starch with 50:50, amylose: amylopectin ratio in combination with smaller Fiber particles resulted in product with significantly greater expansion than the control starch extrudates. Aggregation of Fiber and shrinkage of surface was observed in the Scanning Electron Microscope images at 10% Fiber level. The results suggest the presence of active interactions between the Cellulose Fiber particles and corn starch molecules during the expansion process. A better understanding of these interactions can help in the development of high Fiber extruded products with better expansion. The information generated from this research will help in designing extruded products with high levels of Fiber inclusion. It will also help in selecting the appropriate type of starch material for achieving desired final product expansion.

Hainian Wang - One of the best experts on this subject based on the ideXlab platform.

  • rutting and fatigue properties of Cellulose Fiber added stone mastic asphalt concrete mixtures
    Advances in Materials Science and Engineering, 2019
    Co-Authors: Muhammad Irfan, Yasir Ali, Sarfraz Ahmed, Shahid Iqbal, Hainian Wang
    Abstract:

    This paper investigates dynamic response, rutting resistance, and fatigue behavior of three stone mastic asphalt (SMA) concrete mixtures selected on basis of nominal maximum aggregate size (NMAS): 25 mm, 19 mm, and 12.5 mm using Cellulose Fiber added as 0.3% of the total weight of aggregate. Superpave gyratory specimens were fabricated and subjected to the dynamic modulus ( ) and flow tests (flow number and flow time) using an asphalt mixture performance tester. The test results were employed to develop stress-dependent master curves for each mixture, indicating that the mixture with the NMAS of 25 mm is relatively stiffer than other tested mixtures; this mixture also exhibits excellent strength against rutting failure. In addition, fatigue parameter, which is derived from dynamic response and phase angle, is determined, and results reveal that 12.5 mm NMAS mix has relatively better resistance to fatigue than other selected mixtures. Furthermore, nonlinear regression model specifications were utilized to predict accumulated strains as a function of loading cycles. Also, a flow number model is developed that predicts the rutting behavior of mixtures, and results suggest that model predicted and observed outputs of 25 mm SMA mix are found to be very close. The results of this study help in understanding the performance and behavior of Cellulose Fiber-added stone mastic asphalt concrete mixtures under varying simulated temperature and stress levels, which can be used in areas where the premature failure of flexible pavements is often observed. The testing protocol employed in this study will also help in evaluating pavement performance using Mechanistic-Empirical Pavement Design Guide.

  • Rutting and Fatigue Properties of Cellulose Fiber-Added Stone Mastic Asphalt Concrete Mixtures
    Hindawi Limited, 2019
    Co-Authors: Muhammad Irfan, Yasir Ali, Sarfraz Ahmed, Shahid Iqbal, Hainian Wang
    Abstract:

    This paper investigates dynamic response, rutting resistance, and fatigue behavior of three stone mastic asphalt (SMA) concrete mixtures selected on basis of nominal maximum aggregate size (NMAS): 25 mm, 19 mm, and 12.5 mm using Cellulose Fiber added as 0.3% of the total weight of aggregate. Superpave gyratory specimens were fabricated and subjected to the dynamic modulus (E∗) and flow tests (flow number and flow time) using an asphalt mixture performance tester. The E∗ test results were employed to develop stress-dependent master curves for each mixture, indicating that the mixture with the NMAS of 25 mm is relatively stiffer than other tested mixtures; this mixture also exhibits excellent strength against rutting failure. In addition, fatigue parameter, which is derived from dynamic response and phase angle, is determined, and results reveal that 12.5 mm NMAS mix has relatively better resistance to fatigue than other selected mixtures. Furthermore, nonlinear regression model specifications were utilized to predict accumulated strains as a function of loading cycles. Also, a flow number model is developed that predicts the rutting behavior of mixtures, and results suggest that model predicted and observed outputs of 25 mm SMA mix are found to be very close. The results of this study help in understanding the performance and behavior of Cellulose Fiber-added stone mastic asphalt concrete mixtures under varying simulated temperature and stress levels, which can be used in areas where the premature failure of flexible pavements is often observed. The testing protocol employed in this study will also help in evaluating pavement performance using Mechanistic-Empirical Pavement Design Guide

Gustavo Henrique Denzin Tonoli - One of the best experts on this subject based on the ideXlab platform.

  • Nanoindentation study of the interfacial zone between Cellulose Fiber and cement matrix in extruded composites
    Cement & Concrete Composites, 2018
    Co-Authors: Ronaldo Soares Teixeira, Emilio Rayón, Sérgio Francisco Dos Santos, Vicente Amigó, Gustavo Henrique Denzin Tonoli, Holmer Savastano, Francisco Antonio Rocco Lahr
    Abstract:

    Abstract The present study shows the application of the nanoindentation technique to evaluate the properties of the Cellulose Fiber-cement matrix interfacial zone in composites prepared with an auger extruder. The degree of strength of the bond between Fiber and matrix is recognized as important variable that influences macro-mechanical properties, such as modulus of rupture and toughness of cement based composites. The nanoindentation measurements showed the highest hardness and elastic modulus in the part inner of the cellulosic Fiber after hydration process due to precipitation and re-precipitation of cement hydration products. These results indicate that mineralization of the cellulosic Fibers can affect the stress distribution and interfacial bond strength in the cement based composite.

  • evaluation of reaction factors for deposition of silica sio2 nanoparticles on Cellulose Fibers
    Carbohydrate Polymers, 2014
    Co-Authors: Joabel Raabe, Alessandra De Souza Fonseca, Lina Bufalino, Caue Ribeiro, Maria Alice Martins, Jose Manoel Marconcini, Gustavo Henrique Denzin Tonoli
    Abstract:

    Abstract This study aimed to evaluate reaction conditions for deposition of SiO 2 nanoparticles on the surface of Cellulose Fibers and their influence on moisture adsorption of the hybrid organic–inorganic material formed. SiO 2 nanoparticle deposition was carried out with the sol–gel process testing four reaction times (2, 12, 18, and 24 h) and three contents of the tetraethyl-orthosilicate (TEOS) precursor (1.9, 4.2 and 8.4 g g −1 of Cellulose Fiber). Modification time and TEOS content directly influence the amount of Si deposited on the Fiber surface, nanoparticle diameter distribution, thermal stability, and resistance to moisture adsorption. There is a tendency of slight increase of nanoparticle size and the amount of Si deposited with increasing reaction time. SiO 2 nanoparticles were bonded on the surface of the Cellulose Fibers and are able to improve thermal stability of the material, increasing onset degradation temperature. The moisture adsorption capacity of the modified Cellulose Fiber was reduced up to 50%.