The Experts below are selected from a list of 2544 Experts worldwide ranked by ideXlab platform

Mohammadreza Nofar - One of the best experts on this subject based on the ideXlab platform.

  • Microcellular Foaming Behavior of ether- and ester-based TPUs blown with supercritical CO2
    Journal of Polymer Engineering, 2020
    Co-Authors: Bige Batı, Emine Büşra Küçük, Ali Durmus, Mohammadreza Nofar
    Abstract:

    AbstractThe bead Foaming Behavior of ether- and an ester-based Tensor Processing Unit (TPU) resins were investigated in a lab-scale reactor using supercritical CO2 as the blowing agent. The samples were saturated at various saturation temperatures and the effects of hard segment crystallization during the saturation on the Foaming Behavior of the TPU samples were explored. The results revealed that the different HS crystallization tendencies and possible CO2 solubility differences in two TPU grades led to their different Foaming Behaviors. The ester-based TPU could be foamed within a wider saturation temperature range and revealed an easier cell growth and foam expansion while the ether-based TPU showed a more limited cell growth Behavior and hence processing window. The effect of pre-annealing and hence the isothermally induced HS crystallization on the Foaming Behavior of the ether-based TPU and the influence of depressurization rate on the Foaming Behavior of ester-based TPU was also explored.

  • effect of tpu hard segment content on tpu s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Emine Bursa Kucuk, Bige Batı, Mohammadreza Nofar
    Abstract:

    A lab-scale bead Foaming reactor was used to investigate the Foaming Behavior of thermoplastic polyurethane (TPU) samples with different hard segment contents of around 39 %, 49 % and 57%. The saturation temperature, pressure, and time differently influenced the formation of hard segment crystals with different close-packed structures and sizes. Consequently, with the increase in hard segment crystallization during the saturation the heterogeneous cell nucleation was improved and the foam expansion was controlled by the stiffness of the TPU/CO2 mixture, solubility of CO2, and final shrinkage of the foamed samples. As the saturation temperature increased, the expansion ratio tended to increase with a tendency to shrink more due to the reduced crystallites content. This is while the cell density decreased due to the reduced hard segment crystallites generated during the saturation. Increase in pressure also improved the CO2 solubility and hence the expansion ratio was increased more significantly. The saturation time also influenced the amount and perfection degree of hard segment crystals. The interrelation between the crystallization Behavior of the TPU bead foams and process conditions was reported using differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analysis.

  • Effect of TPU hard segment content on TPU’s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Emine Bursa Kucuk, Bige Batı, Mohammadreza Nofar
    Abstract:

    A lab-scale bead Foaming reactor was used to investigate the Foaming Behavior of thermoplastic polyurethane (TPU) samples with different hard segment contents of around 39 %, 49 % and 57%. The saturation temperature, pressure, and time differently influenced the formation of hard segment crystals with different close-packed structures and sizes. Consequently, with the increase in hard segment crystallization during the saturation the heterogeneous cell nucleation was improved and the foam expansion was controlled by the stiffness of the TPU/CO2 mixture, solubility of CO2, and final shrinkage of the foamed samples. As the saturation temperature increased, the expansion ratio tended to increase with a tendency to shrink more due to the reduced crystallites content. This is while the cell density decreased due to the reduced hard segment crystallites generated during the saturation. Increase in pressure also improved the CO2 solubility and hence the expansion ratio was increased more significantly. The saturation time also influenced the amount and perfection degree of hard segment crystals. The interrelation between the crystallization Behavior of the TPU bead foams and process conditions was reported using differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analysis.

  • Effect of TPU soft segment molecular weight on TPU’s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Bige Batı, Emine Bursa Kucuk, Mohammadreza Nofar
    Abstract:

    The bead Foaming Behavior of three different thermoplastic polyurethane (TPU) samples with different polyol soft-segment molecular weights was investigated through a lab-scale bead Foaming reactor. These TPU samples possessed similar hard-segment content and soft-segment molecular weights of 1000, 2000, and 3500 g/mol. The evolution of the hard-segment crystallization during the isothermal saturation as well as the increased solubility of supercritical CO2 within the soft-segment region are, respectively, determinative parameters on improving the heterogeneous cell nucleation and expansion of the expanded TPU (ETPU) bead foams. The effect of saturation temperature, pressure, and time on the hard-segment crystallization and hence on the Foaming Behavior of TPU samples were explored. The results showed that the increase in soft-segment molecular weight increased the expansion ratio of the bead foams while the processing parameters differently influenced the hard-segment crystallization and CO2 solubility and hence the Foaming Behavior of ETPU foams.

  • Effect of soft segment molecular weight on the microcellular Foaming Behavior of TPU using supercritical CO2
    The Journal of Supercritical Fluids, 2020
    Co-Authors: Mohammadreza Nofar, Bige Batı, Emine Büşra Küçük, Amirjalal Jalali
    Abstract:

    Abstract This study investigates the Foaming Behavior of TPU samples with three different soft segment (SS) molecular weights of 1000, 2000, and 3500 g/mol. The variation of SS length did not only enhance the flexibility of the TPU samples but could also ease the hard segment (HS) crystallization with various size/closed packed structure with much wider HS crystal melting peak. Such broadened melting peak expanded the foam processing window in TPUs with higher SS length. Moreover, the results showed that the increase in SS length could not only enhance the foam expansion Behavior but could also enhance the heterogeneous cell nucleation and more importantly minimize the shrinkage of the TPU foams as a result of broadened HS crystallization. The saturation temperature, pressure, and time could also differently influence the formation of HS crystals in each TPU with different structure which could eventually differently affect the TPUs’ Foaming Behavior.

Bige Batı - One of the best experts on this subject based on the ideXlab platform.

  • Microcellular Foaming Behavior of ether- and ester-based TPUs blown with supercritical CO2
    Journal of Polymer Engineering, 2020
    Co-Authors: Bige Batı, Emine Büşra Küçük, Ali Durmus, Mohammadreza Nofar
    Abstract:

    AbstractThe bead Foaming Behavior of ether- and an ester-based Tensor Processing Unit (TPU) resins were investigated in a lab-scale reactor using supercritical CO2 as the blowing agent. The samples were saturated at various saturation temperatures and the effects of hard segment crystallization during the saturation on the Foaming Behavior of the TPU samples were explored. The results revealed that the different HS crystallization tendencies and possible CO2 solubility differences in two TPU grades led to their different Foaming Behaviors. The ester-based TPU could be foamed within a wider saturation temperature range and revealed an easier cell growth and foam expansion while the ether-based TPU showed a more limited cell growth Behavior and hence processing window. The effect of pre-annealing and hence the isothermally induced HS crystallization on the Foaming Behavior of the ether-based TPU and the influence of depressurization rate on the Foaming Behavior of ester-based TPU was also explored.

  • effect of tpu hard segment content on tpu s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Emine Bursa Kucuk, Bige Batı, Mohammadreza Nofar
    Abstract:

    A lab-scale bead Foaming reactor was used to investigate the Foaming Behavior of thermoplastic polyurethane (TPU) samples with different hard segment contents of around 39 %, 49 % and 57%. The saturation temperature, pressure, and time differently influenced the formation of hard segment crystals with different close-packed structures and sizes. Consequently, with the increase in hard segment crystallization during the saturation the heterogeneous cell nucleation was improved and the foam expansion was controlled by the stiffness of the TPU/CO2 mixture, solubility of CO2, and final shrinkage of the foamed samples. As the saturation temperature increased, the expansion ratio tended to increase with a tendency to shrink more due to the reduced crystallites content. This is while the cell density decreased due to the reduced hard segment crystallites generated during the saturation. Increase in pressure also improved the CO2 solubility and hence the expansion ratio was increased more significantly. The saturation time also influenced the amount and perfection degree of hard segment crystals. The interrelation between the crystallization Behavior of the TPU bead foams and process conditions was reported using differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analysis.

  • Effect of TPU hard segment content on TPU’s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Emine Bursa Kucuk, Bige Batı, Mohammadreza Nofar
    Abstract:

    A lab-scale bead Foaming reactor was used to investigate the Foaming Behavior of thermoplastic polyurethane (TPU) samples with different hard segment contents of around 39 %, 49 % and 57%. The saturation temperature, pressure, and time differently influenced the formation of hard segment crystals with different close-packed structures and sizes. Consequently, with the increase in hard segment crystallization during the saturation the heterogeneous cell nucleation was improved and the foam expansion was controlled by the stiffness of the TPU/CO2 mixture, solubility of CO2, and final shrinkage of the foamed samples. As the saturation temperature increased, the expansion ratio tended to increase with a tendency to shrink more due to the reduced crystallites content. This is while the cell density decreased due to the reduced hard segment crystallites generated during the saturation. Increase in pressure also improved the CO2 solubility and hence the expansion ratio was increased more significantly. The saturation time also influenced the amount and perfection degree of hard segment crystals. The interrelation between the crystallization Behavior of the TPU bead foams and process conditions was reported using differential scanning calorimetry (DSC) and scanning electron microscope (SEM) analysis.

  • Effect of TPU soft segment molecular weight on TPU’s bead Foaming Behavior
    PROCEEDINGS OF THE 35TH INTERNATIONAL CONFERENCE OF THE POLYMER PROCESSING SOCIETY (PPS-35), 2020
    Co-Authors: Bige Batı, Emine Bursa Kucuk, Mohammadreza Nofar
    Abstract:

    The bead Foaming Behavior of three different thermoplastic polyurethane (TPU) samples with different polyol soft-segment molecular weights was investigated through a lab-scale bead Foaming reactor. These TPU samples possessed similar hard-segment content and soft-segment molecular weights of 1000, 2000, and 3500 g/mol. The evolution of the hard-segment crystallization during the isothermal saturation as well as the increased solubility of supercritical CO2 within the soft-segment region are, respectively, determinative parameters on improving the heterogeneous cell nucleation and expansion of the expanded TPU (ETPU) bead foams. The effect of saturation temperature, pressure, and time on the hard-segment crystallization and hence on the Foaming Behavior of TPU samples were explored. The results showed that the increase in soft-segment molecular weight increased the expansion ratio of the bead foams while the processing parameters differently influenced the hard-segment crystallization and CO2 solubility and hence the Foaming Behavior of ETPU foams.

  • Effect of soft segment molecular weight on the microcellular Foaming Behavior of TPU using supercritical CO2
    The Journal of Supercritical Fluids, 2020
    Co-Authors: Mohammadreza Nofar, Bige Batı, Emine Büşra Küçük, Amirjalal Jalali
    Abstract:

    Abstract This study investigates the Foaming Behavior of TPU samples with three different soft segment (SS) molecular weights of 1000, 2000, and 3500 g/mol. The variation of SS length did not only enhance the flexibility of the TPU samples but could also ease the hard segment (HS) crystallization with various size/closed packed structure with much wider HS crystal melting peak. Such broadened melting peak expanded the foam processing window in TPUs with higher SS length. Moreover, the results showed that the increase in SS length could not only enhance the foam expansion Behavior but could also enhance the heterogeneous cell nucleation and more importantly minimize the shrinkage of the TPU foams as a result of broadened HS crystallization. The saturation temperature, pressure, and time could also differently influence the formation of HS crystals in each TPU with different structure which could eventually differently affect the TPUs’ Foaming Behavior.

Tao Tang - One of the best experts on this subject based on the ideXlab platform.

  • the effect of nanosized carbon black on the morphology and sc co2 Foaming Behavior of lldpe ps blends at semi solid state
    Composites Communications, 2018
    Co-Authors: Shaofeng Zhang, Guangchun Zhang, Jian Qiu, Zhiwei Jiang, Haiping Xing, Tao Tang
    Abstract:

    Abstract The influences of nanosized carbon black (CB) on the morphology of immiscible cocontinuous LLDPE/PS blends and their Foaming Behavior under the sc-CO2 batch Foaming was studied. The morphologies and cellular structures of LLDPE/PS blends and LLDPE/PS/CB nanocomposites were characterized by scanning electron microscope (SEM). The results indicated that the introduction of CB nanoparticles could effectively improve Foaming ability of LLDPE/PS=50/50 blends, when enough amount of CB nanofillers was added. This was ascribed to the morphology transformation from cocontinuous structure to sea-island structure due to the presence of CB nanofillers. Furthermore the critical amount of CB for dramatically improving the Foaming capacity depended on the Foaming temperature. In contrast, the addition of CB in the LLDPE/PS blends with spherical dispersed phase (such as 80/20 or 20/80, by weight) did not dramatically change the Foaming Behavior of the blends.

  • The effect of nanosized carbon black on the morphology and sc-CO2 Foaming Behavior of LLDPE/PS blends at semi-solid state
    Composites Communications, 2018
    Co-Authors: Shaofeng Zhang, Guangchun Zhang, Jian Qiu, Zhiwei Jiang, Haiping Xing, Tao Tang
    Abstract:

    Abstract The influences of nanosized carbon black (CB) on the morphology of immiscible cocontinuous LLDPE/PS blends and their Foaming Behavior under the sc-CO2 batch Foaming was studied. The morphologies and cellular structures of LLDPE/PS blends and LLDPE/PS/CB nanocomposites were characterized by scanning electron microscope (SEM). The results indicated that the introduction of CB nanoparticles could effectively improve Foaming ability of LLDPE/PS=50/50 blends, when enough amount of CB nanofillers was added. This was ascribed to the morphology transformation from cocontinuous structure to sea-island structure due to the presence of CB nanofillers. Furthermore the critical amount of CB for dramatically improving the Foaming capacity depended on the Foaming temperature. In contrast, the addition of CB in the LLDPE/PS blends with spherical dispersed phase (such as 80/20 or 20/80, by weight) did not dramatically change the Foaming Behavior of the blends.

  • insight into the influence of oa fe3o4 nanoparticles on the morphology and scco2 batch Foaming Behavior of cocontinuous lldpe ps immiscible blends at semi solid state
    Polymer, 2017
    Co-Authors: Guangchun Zhang, Shaofeng Zhang, Jian Qiu, Zhiwei Jiang, Haiping Xing, Tao Tang
    Abstract:

    Abstract The influence of oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles on the morphology and Foaming Behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of phase structure from cocontinuous structure to sea-island structure, when enough amounts of nanoparticles were added. Meanwhile the introduction of enough amounts of OA-Fe3O4 nanoparticles effectively enhanced the Foaming ability of LLDPE/PS blend at semi-solid state during scCO2 batch Foaming. The mechanism analysis for the change of Foaming Behavior showed that the improved Foaming capacity resulted from the change of the phase structure of LLDPE/PS blends and heterogeneous nucleation of OA-Fe3O4 nanofillers. Sorption and desorption measurements showed that the addition of OA-Fe3O4 nanoparticles in the LLDPE/PS blend increased the solubility of CO2, and the presence of enough amount of OA-Fe3O4 decreased the desorption rate of CO2 in the initial period of depressurization process, which are beneficial to cell nucleation and growth. Furthermore, it was found that the melt Behavior and crystalline properties of LLDPE/PS blends were not the key factors to improved Foaming Behavior of the blends in the presence of OA-Fe3O4 nanoparticles.

  • Insight into the influence of OA-Fe3O4 nanoparticles on the morphology and scCO2 batch-Foaming Behavior of cocontinuous LLDPE/PS immiscible blends at semi-solid state
    Polymer, 2017
    Co-Authors: Guangchun Zhang, Shaofeng Zhang, Jian Qiu, Zhiwei Jiang, Haiping Xing, Tao Tang
    Abstract:

    Abstract The influence of oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles on the morphology and Foaming Behavior of cocontinuous linear low density polyethylene/polystyrene (LLDPE/PS) immiscible blends (60/40 by weight) was studied. The morphology observation showed that the addition of nanofillers resulted in the increased dispersion degree of both LLDPE and PS components and even the transformation of phase structure from cocontinuous structure to sea-island structure, when enough amounts of nanoparticles were added. Meanwhile the introduction of enough amounts of OA-Fe3O4 nanoparticles effectively enhanced the Foaming ability of LLDPE/PS blend at semi-solid state during scCO2 batch Foaming. The mechanism analysis for the change of Foaming Behavior showed that the improved Foaming capacity resulted from the change of the phase structure of LLDPE/PS blends and heterogeneous nucleation of OA-Fe3O4 nanofillers. Sorption and desorption measurements showed that the addition of OA-Fe3O4 nanoparticles in the LLDPE/PS blend increased the solubility of CO2, and the presence of enough amount of OA-Fe3O4 decreased the desorption rate of CO2 in the initial period of depressurization process, which are beneficial to cell nucleation and growth. Furthermore, it was found that the melt Behavior and crystalline properties of LLDPE/PS blends were not the key factors to improved Foaming Behavior of the blends in the presence of OA-Fe3O4 nanoparticles.

Amirjalal Jalali - One of the best experts on this subject based on the ideXlab platform.

  • Effect of soft segment molecular weight on the microcellular Foaming Behavior of TPU using supercritical CO2
    The Journal of Supercritical Fluids, 2020
    Co-Authors: Mohammadreza Nofar, Bige Batı, Emine Büşra Küçük, Amirjalal Jalali
    Abstract:

    Abstract This study investigates the Foaming Behavior of TPU samples with three different soft segment (SS) molecular weights of 1000, 2000, and 3500 g/mol. The variation of SS length did not only enhance the flexibility of the TPU samples but could also ease the hard segment (HS) crystallization with various size/closed packed structure with much wider HS crystal melting peak. Such broadened melting peak expanded the foam processing window in TPUs with higher SS length. Moreover, the results showed that the increase in SS length could not only enhance the foam expansion Behavior but could also enhance the heterogeneous cell nucleation and more importantly minimize the shrinkage of the TPU foams as a result of broadened HS crystallization. The saturation temperature, pressure, and time could also differently influence the formation of HS crystals in each TPU with different structure which could eventually differently affect the TPUs’ Foaming Behavior.

Emine Büşra Küçük - One of the best experts on this subject based on the ideXlab platform.

  • Microcellular Foaming Behavior of ether- and ester-based TPUs blown with supercritical CO2
    Journal of Polymer Engineering, 2020
    Co-Authors: Bige Batı, Emine Büşra Küçük, Ali Durmus, Mohammadreza Nofar
    Abstract:

    AbstractThe bead Foaming Behavior of ether- and an ester-based Tensor Processing Unit (TPU) resins were investigated in a lab-scale reactor using supercritical CO2 as the blowing agent. The samples were saturated at various saturation temperatures and the effects of hard segment crystallization during the saturation on the Foaming Behavior of the TPU samples were explored. The results revealed that the different HS crystallization tendencies and possible CO2 solubility differences in two TPU grades led to their different Foaming Behaviors. The ester-based TPU could be foamed within a wider saturation temperature range and revealed an easier cell growth and foam expansion while the ether-based TPU showed a more limited cell growth Behavior and hence processing window. The effect of pre-annealing and hence the isothermally induced HS crystallization on the Foaming Behavior of the ether-based TPU and the influence of depressurization rate on the Foaming Behavior of ester-based TPU was also explored.

  • Effect of soft segment molecular weight on the microcellular Foaming Behavior of TPU using supercritical CO2
    The Journal of Supercritical Fluids, 2020
    Co-Authors: Mohammadreza Nofar, Bige Batı, Emine Büşra Küçük, Amirjalal Jalali
    Abstract:

    Abstract This study investigates the Foaming Behavior of TPU samples with three different soft segment (SS) molecular weights of 1000, 2000, and 3500 g/mol. The variation of SS length did not only enhance the flexibility of the TPU samples but could also ease the hard segment (HS) crystallization with various size/closed packed structure with much wider HS crystal melting peak. Such broadened melting peak expanded the foam processing window in TPUs with higher SS length. Moreover, the results showed that the increase in SS length could not only enhance the foam expansion Behavior but could also enhance the heterogeneous cell nucleation and more importantly minimize the shrinkage of the TPU foams as a result of broadened HS crystallization. The saturation temperature, pressure, and time could also differently influence the formation of HS crystals in each TPU with different structure which could eventually differently affect the TPUs’ Foaming Behavior.

  • Effect of hard segment content on the microcellular Foaming Behavior of TPU using supercritical CO2
    The Journal of Supercritical Fluids, 2019
    Co-Authors: Mohammadreza Nofar, Emine Büşra Küçük, Bige Batı
    Abstract:

    Abstract A lab-scale reactor was used to investigate the Foaming Behavior of three different thermoplastic polyurethane (TPU) grades with different hard segment (HS) contents of around 39%, 49% and 57 wt%. The effect of HS content on the Foaming Behavior of TPU was extensively analyzed while varying the foam processing parameters. The saturation temperature, pressure, and time differently influenced the formation of HS crystals in each TPU with different closed-pack structures and sizes. With the increase in HS crystallization during the saturation the heterogeneous cell nucleation was improved and the foam expansion was controlled by the melt strength of the TPU/CO2 mixture, solubility of CO2, and the final shrinkage of the foamed samples. In TPUs with higher HS content, the processing window was broadened and shifted to higher temperatures while the expansion ratio was limited and shrinkage was minimized.