The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Michel Nardin - One of the best experts on this subject based on the ideXlab platform.

  • Influence of the grade on the variability of the mechanical properties of polypropylene waste
    Waste Management, 2018
    Co-Authors: Hamdi Jmal, Nadia Bahlouli, Christiane Wagner-kocher, Dimitri Leray, Frédéric Ruch, Jean-nicolas Munsch, Michel Nardin
    Abstract:

    The prior properties of recycled polypropylene depend on the origin of waste deposits and its chemical constituents. To obtain specific properties with a predefine Melt Flow Index of polypropylene, the suppliers of polymer introduce additives and fillers. However, the addition of additives and/or fillers can modify strongly the mechanical behaviour of recycled polypropylene. To understand the impact of the additives and fillers on the quasi-static mechanical behaviour, we consider, in this study, three different recycled polypropylenes with three different Melt Flow Index obtained from different waste deposits. The chemical constituents of the additives and filler contents of the recycled polypropylenes are determined through thermo-physico-chemical analysis. Tensile and bending tests performed at different strain rates allow identifying the mechanical properties such as the elastic modulus, the yield stress, the maximum stress, and the failure mechanisms. The results obtained are compared with non-recycled polypropylene and with few researches to explain the combined effect of additives. Finally, a post-mortem analysis of the samples was carried out to make the link between the obtained mechanical properties and microstructure.

Babak Bozorgi - One of the best experts on this subject based on the ideXlab platform.

  • The effect of Melt Flow Index, Melt Flow rate, and particle size on the thermal degradation of commercial high density polyethylene powder
    Journal of Thermal Analysis and Calorimetry, 2013
    Co-Authors: Mehrdad Seifali Abbas-abadi, Hamid Yeganeh, Mehdi Nekoomanesh Haghighi, Babak Bozorgi
    Abstract:

    The powder of EX5 grade of high density polyethylene—without any additives—manufactured by Amirkabir petrochemical company was separated by shaker equipment. The separated powder of average diameter ~25, ~62.5, ~87.5, ~112.5, ~137.5, ~175 and the particles >200 μm was tested by a thermogravimetric (TG) analysis instrument in nitrogen atmosphere and heating rates of 10, 20, and 30 °C min^−1. In addition, the separated powders were analyzed by a Melt Flow Index (MFI) instrument, and the viscosity average molecular mass ( M _v) of the powders was tested by a viscometer. Kinetic evaluations were performed by Friedman and Kissinger analysis methods and apparent activation energy for the overall degradation of the powders was determined. The effects of molecular mass, MFI, MFR, and particle size on the degradation TG curve, derivative thermogravimetry curve breadth, and activation energy of thermal degradation were considered. The results showed that the M _v of EX5 pipe grade produced by two serial reactors is increased by increasing of the particle size and, MFI is decreased with a little deviation by particle size increasing. The particle size has no obvious effect on the Melt Flow rate (MFR), and MFR as function of molecular mass distribution does not change very much. The results showed that the powder with bigger particles and higher molecular mass moderately increases the activation energy and shifts the degradation curve to the higher temperatures.

Hamdi Jmal - One of the best experts on this subject based on the ideXlab platform.

  • Influence of the grade on the variability of the mechanical properties of polypropylene waste
    Waste Management, 2018
    Co-Authors: Hamdi Jmal, Nadia Bahlouli, Christiane Wagner-kocher, Dimitri Leray, Frédéric Ruch, Jean-nicolas Munsch, Michel Nardin
    Abstract:

    The prior properties of recycled polypropylene depend on the origin of waste deposits and its chemical constituents. To obtain specific properties with a predefine Melt Flow Index of polypropylene, the suppliers of polymer introduce additives and fillers. However, the addition of additives and/or fillers can modify strongly the mechanical behaviour of recycled polypropylene. To understand the impact of the additives and fillers on the quasi-static mechanical behaviour, we consider, in this study, three different recycled polypropylenes with three different Melt Flow Index obtained from different waste deposits. The chemical constituents of the additives and filler contents of the recycled polypropylenes are determined through thermo-physico-chemical analysis. Tensile and bending tests performed at different strain rates allow identifying the mechanical properties such as the elastic modulus, the yield stress, the maximum stress, and the failure mechanisms. The results obtained are compared with non-recycled polypropylene and with few researches to explain the combined effect of additives. Finally, a post-mortem analysis of the samples was carried out to make the link between the obtained mechanical properties and microstructure.

Hamid Yeganeh - One of the best experts on this subject based on the ideXlab platform.

  • The effect of Melt Flow Index, Melt Flow rate, and particle size on the thermal degradation of commercial high density polyethylene powder
    Journal of Thermal Analysis and Calorimetry, 2013
    Co-Authors: Mehrdad Seifali Abbas-abadi, Hamid Yeganeh, Mehdi Nekoomanesh Haghighi, Babak Bozorgi
    Abstract:

    The powder of EX5 grade of high density polyethylene—without any additives—manufactured by Amirkabir petrochemical company was separated by shaker equipment. The separated powder of average diameter ~25, ~62.5, ~87.5, ~112.5, ~137.5, ~175 and the particles >200 μm was tested by a thermogravimetric (TG) analysis instrument in nitrogen atmosphere and heating rates of 10, 20, and 30 °C min^−1. In addition, the separated powders were analyzed by a Melt Flow Index (MFI) instrument, and the viscosity average molecular mass ( M _v) of the powders was tested by a viscometer. Kinetic evaluations were performed by Friedman and Kissinger analysis methods and apparent activation energy for the overall degradation of the powders was determined. The effects of molecular mass, MFI, MFR, and particle size on the degradation TG curve, derivative thermogravimetry curve breadth, and activation energy of thermal degradation were considered. The results showed that the M _v of EX5 pipe grade produced by two serial reactors is increased by increasing of the particle size and, MFI is decreased with a little deviation by particle size increasing. The particle size has no obvious effect on the Melt Flow rate (MFR), and MFR as function of molecular mass distribution does not change very much. The results showed that the powder with bigger particles and higher molecular mass moderately increases the activation energy and shifts the degradation curve to the higher temperatures.

  • Effect of the Melt Flow Index and Melt Flow rate on the thermal degradation kinetics of commercial polyolefins
    Journal of Applied Polymer Science, 2012
    Co-Authors: Mehrdad Seifali Abbas-abadi, Mehdi Nekoomanesh Haghighi, Hamid Yeganeh
    Abstract:

    In this study, several polyolefins, including different grades of polypropylene (PP), high-density polyethylene, linear low-density polyethylene, and low-density polyethylene, were tested by thermogravimetric analysis (TGA), and the relationships of their Melt Flow Index (MFI) and Melt Flow ratio (MFR) values to the thermogravimetry (TG) curves, differential thermogravimetry (DTG) curves, and activation energy of thermal degradation were investigated. Kinetic evaluations were performed by Friedman and Kissinger analysis methods, and the apparent activation energy values for the overall degradation of different grades of polyethylenes (PEs) and PPs were determined. We found that for the samples with lower MFIs, the thermograms shifted to higher temperatures. Meanwhile, a higher activation energy was needed for their thermal degradation. Also, for samples with higher values of MFR, as a means of molecular weight distribution, a lower activation energy was needed for their thermal degradation, and their TGA thermograms shifted to lower temperatures. The breadth of the DTG curves depended on the MFR in the PEs, although MFR had little effect on the DTG curves in the studied PP grades. Among all of the samples studied, the injection-molding grades with medium MFIs and low MFRs degraded at higher temperatures and showed better thermal stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012

Mehrdad Seifali Abbas-abadi - One of the best experts on this subject based on the ideXlab platform.

  • The effect of Melt Flow Index, Melt Flow rate, and particle size on the thermal degradation of commercial high density polyethylene powder
    Journal of Thermal Analysis and Calorimetry, 2013
    Co-Authors: Mehrdad Seifali Abbas-abadi, Hamid Yeganeh, Mehdi Nekoomanesh Haghighi, Babak Bozorgi
    Abstract:

    The powder of EX5 grade of high density polyethylene—without any additives—manufactured by Amirkabir petrochemical company was separated by shaker equipment. The separated powder of average diameter ~25, ~62.5, ~87.5, ~112.5, ~137.5, ~175 and the particles >200 μm was tested by a thermogravimetric (TG) analysis instrument in nitrogen atmosphere and heating rates of 10, 20, and 30 °C min^−1. In addition, the separated powders were analyzed by a Melt Flow Index (MFI) instrument, and the viscosity average molecular mass ( M _v) of the powders was tested by a viscometer. Kinetic evaluations were performed by Friedman and Kissinger analysis methods and apparent activation energy for the overall degradation of the powders was determined. The effects of molecular mass, MFI, MFR, and particle size on the degradation TG curve, derivative thermogravimetry curve breadth, and activation energy of thermal degradation were considered. The results showed that the M _v of EX5 pipe grade produced by two serial reactors is increased by increasing of the particle size and, MFI is decreased with a little deviation by particle size increasing. The particle size has no obvious effect on the Melt Flow rate (MFR), and MFR as function of molecular mass distribution does not change very much. The results showed that the powder with bigger particles and higher molecular mass moderately increases the activation energy and shifts the degradation curve to the higher temperatures.