The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Craig M Clemons - One of the best experts on this subject based on the ideXlab platform.
-
elastomer modified polypropylene polyethylene blends as matrices for wood flour plastic composites
Composites Part A-applied Science and Manufacturing, 2010Co-Authors: Craig M ClemonsAbstract:Abstract Blends of polyethylene (PE) and polypropylene (PP) could potentially be used as matrices for wood–plastic composites (WPCs). The mechanical performance and morphology of both the unfilled blends and wood-filled composites with various elastomers and coupling agents were investigated. Blending of the plastics resulted in either small domains of the minor phase in a matrix of major phase or a co-continuous morphology if equal amounts of HDPE and PP were added. The tensile moduli and yield properties of the blends were clearly proportional to the relative amounts of HDPE and PP in the blends. However, the Nominal Strain at break and the notched Izod impact energies of HDPE were greatly reduced by adding as little as 25% of the PP. Adding an ethylene–propylene–diene (EPDM) elastomer to the blends, reduced moduli and strength but increased elongational properties and impact energies, especially in HDPE-rich blends. Adding wood flour to the blends stiffened but embrittled them, especially the tougher, HDPE-rich blends, though the reductions in performance could be offset somewhat by adding elastomers and coupling agents or a combination of both.
-
elastomer modified polypropylene polyethylene blends as matrices for wood flour plastic composites
Composites Part A-applied Science and Manufacturing, 2010Co-Authors: Craig M ClemonsAbstract:Abstract Blends of polyethylene (PE) and polypropylene (PP) could potentially be used as matrices for wood–plastic composites (WPCs). The mechanical performance and morphology of both the unfilled blends and wood-filled composites with various elastomers and coupling agents were investigated. Blending of the plastics resulted in either small domains of the minor phase in a matrix of major phase or a co-continuous morphology if equal amounts of HDPE and PP were added. The tensile moduli and yield properties of the blends were clearly proportional to the relative amounts of HDPE and PP in the blends. However, the Nominal Strain at break and the notched Izod impact energies of HDPE were greatly reduced by adding as little as 25% of the PP. Adding an ethylene–propylene–diene (EPDM) elastomer to the blends, reduced moduli and strength but increased elongational properties and impact energies, especially in HDPE-rich blends. Adding wood flour to the blends stiffened but embrittled them, especially the tougher, HDPE-rich blends, though the reductions in performance could be offset somewhat by adding elastomers and coupling agents or a combination of both.
Xiaoming Wang - One of the best experts on this subject based on the ideXlab platform.
-
microstructure based numerical simulation of the mechanical properties and fracture of a ti al3ti core shell structured particulate reinforced a356 composite
Materials & Design, 2020Co-Authors: Xuezheng Zhang, T J Chen, Xiaoming WangAbstract:Abstract A microstructure-based numerical simulation is performed to understand the mechanical properties and fracture of a Ti-Al3Ti core-shell structured particulate reinforced A356 composite ((Ti-Al3Ti)cs/A356). A series of two-dimensional (2D) representative volume element (RVE) models are generated automatically by embedding Ti-Al3Ti core-shell structured particulates in an A356 matrix. Microstructure-based 2D RVE of monolithic Al3Ti particulate reinforced A356 composite (Al3Tip/A356) is also simulated for comparison. The ductile fracture of both Ti core and A356 matrix as well as the brittle fracture of the Al3Ti shell are considered. The simulation confirms that the high elongation of the (Ti-Al3Ti)cs/A356 composite is attributed to the uniform distribution of the overall ductile globular reinforcing particulates, which prevent a premature failure effectively by reducing local stress concentration both on and inside the core-shell structured particulates. The surrounding ductile phases of the Al3Ti shell blunt the crack tips effectively and, therefore, restricting the propagation of the cracks in a Nominal Strain range of 2.2%–6.1%. For both (Ti-Al3Ti)cs/A356 and Al3Tip/A356 composites, the simulation results are in good agreement with microstructural observations during an in-situ tensile test in a scanning electron microscope.
Thomas Sango - One of the best experts on this subject based on the ideXlab platform.
-
step wise multi scale deconstruction of banana pseudo stem musa acuminata biomass and morpho mechanical characterization of extracted long fibres for sustainable applications
Industrial Crops and Products, 2018Co-Authors: Thomas Sango, Arnaud Maxime Cheumani Yona, Lucie Duchatel, Adeline Marin, Maurice Kor Ndikontar, Nicolas Joly, J M LefebvreAbstract:Abstract Banana Pseudo–stem (BPS) is an annual renewable agricultural by–product with a potential for valorization in the production of paper, textile fibre or new bio–based materials. A gradual deconstruction process was implemented to determine BPS chemical composition and isolate sub–components that may be valorized in the formulation of bio–based polymer composites. At each step, the residues were analyzed by FTIR, X–ray diffraction and TGA–DTG. The chemical composition of the starting material (% of dry weight) was evaluated as: 13.4% total extractives, 6% pectins, 14.7% lignins, 28% hemicelluloses and 38% cellulose. The deconstruction process for BPS was efficient but led to mercerized cellulose (cellulose II) as a final residue, as assessed by the intense X–ray scattering peaks centered at 20.5° and 21.5°. Cellulose II formation was induced by the high concentration of the alkaline KOH solution used to dissolve hemicelluloses in holocellulose. The step–wise removal of non–cellulosic sub–components led to a more thermally stable residue. Long fibres were also obtained from BPS at a yield of 60%. These fibres display cellulose I structure and a thermal stability similar to the extracted cellulose. SEM analyses of long fibres showed transversal and lateral defects, the presence of surface hairiness and an almost cylindrical morphology. Uniaxial tensile tests were carried out at room temperature on 150 specimens randomly chosen among the less hairy fibres, with diameters ranging from 40 to 140 μm. Mechanical investigations (Young modulus: 6.3–26 GPa; Nominal stress at break: 140–768 MPa; Nominal Strain at break: ∼3%) reveal a significant disparity strongly influenced by fibre diameter, except for the Nominal Strain at break which remains fairly constant around 3%. These results are comparable to the upper range of the values reported for fibres extracted from BPS through alternative chemical routes or for fibres obtained from other annual plants such as jute and hemp.
Xuezheng Zhang - One of the best experts on this subject based on the ideXlab platform.
-
microstructure based numerical simulation of the mechanical properties and fracture of a ti al3ti core shell structured particulate reinforced a356 composite
Materials & Design, 2020Co-Authors: Xuezheng Zhang, T J Chen, Xiaoming WangAbstract:Abstract A microstructure-based numerical simulation is performed to understand the mechanical properties and fracture of a Ti-Al3Ti core-shell structured particulate reinforced A356 composite ((Ti-Al3Ti)cs/A356). A series of two-dimensional (2D) representative volume element (RVE) models are generated automatically by embedding Ti-Al3Ti core-shell structured particulates in an A356 matrix. Microstructure-based 2D RVE of monolithic Al3Ti particulate reinforced A356 composite (Al3Tip/A356) is also simulated for comparison. The ductile fracture of both Ti core and A356 matrix as well as the brittle fracture of the Al3Ti shell are considered. The simulation confirms that the high elongation of the (Ti-Al3Ti)cs/A356 composite is attributed to the uniform distribution of the overall ductile globular reinforcing particulates, which prevent a premature failure effectively by reducing local stress concentration both on and inside the core-shell structured particulates. The surrounding ductile phases of the Al3Ti shell blunt the crack tips effectively and, therefore, restricting the propagation of the cracks in a Nominal Strain range of 2.2%–6.1%. For both (Ti-Al3Ti)cs/A356 and Al3Tip/A356 composites, the simulation results are in good agreement with microstructural observations during an in-situ tensile test in a scanning electron microscope.
J M Lefebvre - One of the best experts on this subject based on the ideXlab platform.
-
step wise multi scale deconstruction of banana pseudo stem musa acuminata biomass and morpho mechanical characterization of extracted long fibres for sustainable applications
Industrial Crops and Products, 2018Co-Authors: Thomas Sango, Arnaud Maxime Cheumani Yona, Lucie Duchatel, Adeline Marin, Maurice Kor Ndikontar, Nicolas Joly, J M LefebvreAbstract:Abstract Banana Pseudo–stem (BPS) is an annual renewable agricultural by–product with a potential for valorization in the production of paper, textile fibre or new bio–based materials. A gradual deconstruction process was implemented to determine BPS chemical composition and isolate sub–components that may be valorized in the formulation of bio–based polymer composites. At each step, the residues were analyzed by FTIR, X–ray diffraction and TGA–DTG. The chemical composition of the starting material (% of dry weight) was evaluated as: 13.4% total extractives, 6% pectins, 14.7% lignins, 28% hemicelluloses and 38% cellulose. The deconstruction process for BPS was efficient but led to mercerized cellulose (cellulose II) as a final residue, as assessed by the intense X–ray scattering peaks centered at 20.5° and 21.5°. Cellulose II formation was induced by the high concentration of the alkaline KOH solution used to dissolve hemicelluloses in holocellulose. The step–wise removal of non–cellulosic sub–components led to a more thermally stable residue. Long fibres were also obtained from BPS at a yield of 60%. These fibres display cellulose I structure and a thermal stability similar to the extracted cellulose. SEM analyses of long fibres showed transversal and lateral defects, the presence of surface hairiness and an almost cylindrical morphology. Uniaxial tensile tests were carried out at room temperature on 150 specimens randomly chosen among the less hairy fibres, with diameters ranging from 40 to 140 μm. Mechanical investigations (Young modulus: 6.3–26 GPa; Nominal stress at break: 140–768 MPa; Nominal Strain at break: ∼3%) reveal a significant disparity strongly influenced by fibre diameter, except for the Nominal Strain at break which remains fairly constant around 3%. These results are comparable to the upper range of the values reported for fibres extracted from BPS through alternative chemical routes or for fibres obtained from other annual plants such as jute and hemp.
