The Experts below are selected from a list of 123 Experts worldwide ranked by ideXlab platform

Sung Woon Cha - One of the best experts on this subject based on the ideXlab platform.

  • Factors That Affect Diffuse Reflection Performance of Microcellular Foamed Plastics
    Polymer-Plastics Technology and Engineering, 2013
    Co-Authors: Earl Han, Sung Woon Cha
    Abstract:

    The structure of microcellular Foamed Plastics causes optical, acoustic, and electrical properties. The diffuse reflection performance of microcellular Foamed Plastics can be applied as a high performance diffuse reflector. To improve microcellular foaming process, a simulation was conducted. It was to analyze the factor affecting when microcellular Foamed Plastics realized the diffuse reflection performance. Cell morphology of microcellular Foamed Plastics can be expressed through four factors. From result of simulation made a data base about cell morphology and diffuse reflectance. And the statistical method was used for identify contributions by factors.

  • A study on the foaming ratio and optical characteristics of microcellular Foamed Plastics produced by a repetitive foaming process
    International Journal of Precision Engineering and Manufacturing, 2013
    Co-Authors: Soohyun Cho, Sung Woon Cha, Jung Hwan Seo, Jeonghun Ahn
    Abstract:

    Microcellular foaming technology has had a great influence on the polymer progress. According to the previous studies, polymer material has the same mechanical strength as general plastic molding products but it can have a lighter weight, and it has the features of insulation and noise suppression. In addition, it shows excellent diffused reflectivity since it has micro-sized cells. This study intends to determine the change microcellular foaming process conditions; it also intends to determine the optical characteristics, And the results of this experiment are shown through foaming ratio, diffused reflectivity, and cell morphology. We examined changes in cell morphology in the inner regions of polycarbonate (PC) samples and the resulting changes in foaming ratios. We also examined the optical characteristics that result when a repetitive foaming process is performed using polymer samples that have already undergone an initial microcellular foaming process. Polycarbonate is an amorphous material with exceptional optical characteristics. The saturation pressure was varied during both the first foaming process and the repetitive foaming process, and the results of the experiment were expressed in terms of foaming ratio, diffused reflectivity, and cell morphology.

  • changes in the reflectivity and color characteristics of microcellular Foamed Plastics
    Polymer-plastics Technology and Engineering, 2012
    Co-Authors: Earl Han, Youngho Kim, Sung Woon Cha
    Abstract:

    As the use of Plastics has increased in various industries, research on microcellular Plastics has increased as well. The microcellular foaming process helps produce lighter plastic and reduces material consumption. This process also affects the optical properties. The primary purpose of this study is to measure the visible changes occurring in polymer samples by comparing changes in the samples before and after the microcellular foaming process. To measure the changes in color characteristics, colored PC samples were utilized for the experiments. Changes in the color characteristics were indicated using the Munsell color system.

  • the effect of gas desorption on foaming ratio of microcellular Foamed Plastics
    Polymer-plastics Technology and Engineering, 2011
    Co-Authors: Jung Hwan Seo, Wonsuk Ohm, Soohyun Cho, Sung Woon Cha
    Abstract:

    Microcellular Plastics (MCPs) are one of the most significant developments in the Plastics industry over the last decade. Microcellular Plastics keep mechanical strength loss and plastic weight to a minimum through microcells inside MCPs. The size and number of cells inside MCPs have a direct correlation with foaming ratio. The cell size has to be consistent to ensure higher quality of MCPs, and a great number of cells are needed for a high foaming ratio. This underscores the need to control the size and number of cells to meet products' required performance. In the microcellular batch process, saturation and foaming conditions are major factors that influence the size and number of cells. This article describes how desorption time, defined as the time lapse between saturation and foaming processes, affects cell formation. Our particular concern is the effect of varying desorption time on foaming ratio and cell morphology. The general rule is that the shorter the desorption time, the higher the foaming ra...

Irina P. Chubarenko - One of the best experts on this subject based on the ideXlab platform.

  • Image_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.pdf
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

  • Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments
    Frontiers Media S.A., 2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed

  • Video_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.MP4
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

  • Data_Sheet_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.xlsx
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

Hongru Lin - One of the best experts on this subject based on the ideXlab platform.

  • the structure and property relationships of commercial Foamed Plastics
    Polymer Testing, 1997
    Co-Authors: Hongru Lin
    Abstract:

    The mechanical characteristics of Foamed Plastics, based on commercial foams, were studied by observing the role of cell content (foam and relative densities, dimensions of cell edge and face, cell wall, cell shape, etc.) on stress-strain behavior and deformation mechanisms. It is found that the stress-strain behaviour in compression and tension for PVC commercial foam are different beyond linear elastic deformation since cell wall deformations involve different processes. Cell wall thickness which is directly related to foam density dominates the mechanical properties of plastic foams. The regimes of the stress-strain curve are related to the structure of the foam. The foam deformation structure was identified by SEM micrographs which assisted in the interpretation of deformation mechanisms. The mechanical properties of these plastic foams were also characterized in terms of relative density and the degree to which the cells are open or closed. It is found that relative density was found to be a function of geometric aspects of cell structure such as edge and face connectivity, edge and face thickness, etc, which are critical to the understanding of the mechanical properties.

Irina Efimova - One of the best experts on this subject based on the ideXlab platform.

  • Image_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.pdf
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

  • Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments
    Frontiers Media S.A., 2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed

  • Video_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.MP4
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

  • Data_Sheet_1_Secondary MicroPlastics Generation in the Sea Swash Zone With Coarse Bottom Sediments: Laboratory Experiments.xlsx
    2018
    Co-Authors: Irina Efimova, Margarita Bagaeva, Andrei Bagaev, Alexander Kileso, Irina P. Chubarenko
    Abstract:

    Marine beaches worldwide are nowadays exposed to significant contamination by Plastics. On the Baltic beaches, polyethylene, polypropylene, and polystyrene are most abundant. We investigate the generation of microPlastics particles (MPs, characteristic size from 0.5 to 5 mm) from larger plastic items in the sea swash zone using a laboratory rotating mixer filled with water and natural coarse beach sediment (marine pebbles). Inclination of the axis of rotation and the volume of the material were adjusted in such a way that mixing resembled a breaking wave in the swash zone. Plastic samples used were of the types most commonly found on the sea beaches. Experimental 2 × 2 cm-large plastic items made of low-density polyethylene (LDPE) were manufactured from common new garbage bags (thickness 5 μm); those made of polypropylene (PP) and polystyrene (PS) were produced from single-use tableware; samples of Foamed Plastics were presented by cubes (with 2-cm sides) cut out of standard building insulator sheets (Foamed PS). Four sets of 24-h-long experiments were conducted (for each type of plastic separately), with step-wise (every 3 h) examination of the generated MPs mass, number of particles, and their qualitative characteristics such as shape, quality of the surface, general behavior while mixing, etc. Statistically significant dependencies are obtained for the increase in mass and in number of MPs with time for all four used kinds of Plastics. Brittle solid PS is shown to be the most productive in terms of both mass and number of MPs generated. Anisotropic springing PP is the most resistant. Tensile tearing of LDPE and fragmentation of Foamed PS to compounding bubbles/spherules show the variety of mechanisms involved in fragmentation of Plastics in the swash zone. Increase in MPs mass and the number of MPs particles with time, as well the link between them, are important for field monitoring and numerical modeling. Potentially shape-selective operation of sieves during sampling and sorting of MPs particles of various shapes is discussed.

Hiromasa Adachi - One of the best experts on this subject based on the ideXlab platform.

  • evaluation of thermal endurance characteristics of thermosetting polyurethane elastomers and polyurethane foams by dynamic compression modulus
    Kobunshi Ronbunshu, 2006
    Co-Authors: Hiromasa Adachi
    Abstract:

    For evaluation of thermal endurance of elastomers and Foamed Plastics, the time dependences of compression dynamic modulus of thermosetting polyurethane elastomers, and of micro-cell, hard and flexible polyurethane foams were investigated by dynamic viscoelastic measurements. In the temperature range of interest, 140∼290°C, compression dynamic modulus of each elastomer and each foam lessened gradually with time, which is presumably due to thermal degradation of the elastomers and foams. The logarithm of the time t at which the compression dynamic modulus came to be 50% of its value at the beginning of the dynamic measurement was found to be a linear function of reciprocal temperature T-1. Therefore, thermal endurance characteristics of thermosetting polyurethane elastomers and polyurethane foams can be evaluated as well as closed-celled polyethylene foams from the linear relations between T-1 and the logarithm of time t at which the compression dynamic modulus came to be 50% of its initial value. The loss tangent of elastomer differs from that of foam. Thermal degradation is determined by compression deformation in elastomers that have no cells and by the bending deformation in foam that have closed or open cells.

  • evaluation of thermal endurance characteristics of closed celled polyethylene foams by using dynamic compression modulus
    Kobunshi Ronbunshu, 2005
    Co-Authors: Hiromasa Adachi, Teruo Hasegawa
    Abstract:

    For evaluation of thermal endurance in Foamed Plastics, the time characteristics of the compression dynamic modulus of three closedcell polyethylene foams were investigated by the dynamic viscoelastic measurements. The logarithm of the time (t), at which the compression dynamic modulus came to be 50% of its initial value at the beginning of the dynamic measurement has been found to be a linear function of the reciprocal of the absolute temperature T-1. The correlation coefficient was more than 0.91. Thermal endurance characteristics can be evaluated from the linear relations between log t and T-1.