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Average Cell Size (average + cell_size)

Distribution by Scientific Domains
Polymers and Materials Science75%

Selected Abstracts

Effect of processing parameters on the cellular morphology and mechanical properties of thermoplastic polyolefin (TPO) microcellular foams

ADVANCES IN POLYMER TECHNOLOGY, Issue 4 2007
Steven Wong
Abstract In this study, the effects of processing parameters on the cellular morphologies and mechanical properties of thermoplastic polyolefin (TPO) microcellular foams are investigated. Microcellular closed cell TPO foams were prepared using a two-stage batch process method. The microstructure of these foamed samples was controlled by carefully altering the processing parameters such as saturation pressure, foaming temperature, and foaming time. Foam morphologies were characterized in terms of the cell density, foam density, and average cell size. Elastic modulus, tensile strength, and elongation at break of the foamed TPO samples were measured for different cell morphologies. The findings show that the mechanical properties are significantly affected by the foaming parameters that varied with the cell morphologies. The experimental results can be used to predict the microstructure and mechanical properties of microcellular polymeric TPO foams prepared with different processing parameters. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:232,246, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20104 [source]

Effect of dispersion state of organoclay on cellular foam structure and mechanical properties of ethylene vinyl acetate copolymer/ethylene-1-butenecopolymer/organoclay nanocomposite foams

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2007
Keun-Wan Park
Abstract In this study, our goal is to obtain lower density of ethylene-vinyl acetate copolymer (EVA)/ethylene-1-butene copolymer (EtBC) foams without sacrificing mechanical properties. For this purpose EVA/EtBC/organoclay (Cloisite 15A, Closite 30B) nanocomposite foams were prepared. To investigate the effect of compatibilizer on the dispersion state of organoclay in cellular foam structure and mechanical properties of the EVA/EtBC/organoclay foams composites were prepared with and without maleic anhydride grafted EtBC (EtBC-g-MAH). The dispersion of organoclay in EVA/EtBC/organocaly foams was investigated by X-ray diffraction and transmission electron microscopy. The EVA/EtBC nanocomposite foamswith the compatibilzer, especially EVA/EtBC/Cloisite 15A/EtBC-g-MAH foams displayed more uniform dispersion of organoclay than EVA/EtBC nanocomposite foams without the compatibilzer. As a result, EVA/EtBC/Cloisite 15A/EtBC-g-MAH foams have the smallest average cell size and highest 100% tensile modulus followed by EVA/EtBC/Cloisite 30B/EtBC-g-MAH foams. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3879,3885, 2007 [source]

Relationship between cell morphology and impact strength of microcellular foamed high-density polyethylene/polypropylene blends

POLYMER ENGINEERING & SCIENCE, Issue 8 2004
Pornchai Rachtanapun
Polymer blends, such as those resulting from recycling postconsumer plastics, often have poor mechanical properties. Microcellular foams have been shown to have the potential to improve properties, and permit higher-value uses of mixed polymer streams. In this study, the effects of microcellular batch processing conditions (foaming time and temperature) and HDPE/PP blend compositions on the cell morphology (the average cell size and cell-population density) and impact strength were studied. Optical microscopy was used to investigate the miscibility and crystalline morphology of the HDPE/PP blends. Pure HDPE and PP did not foam well at any processing conditions. Blending facilitated the formation of microcellular structures in polyolefins because of the poorly bonded interfaces of immiscible HDPE/PP blends, which favored cell nucleation. The experimental results indicated that well-developed microcellular structures are produced in HDPE/PP blends at ratios of 50:50 and 30:70. The cell morphology had a strong relationship with the impact strength of foamed samples. Improvement in impact strength was associated with well-developed microcellular morphology. Polym. Eng. Sci. 44:1551,1560, 2004. © 2004 Society of Plastics Engineers. [source]

Macroporous Ceramics from Particle-Stabilized Wet Foams

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2007
Urs T. Gonzenbach
We present a novel direct-foaming method to produce macroporous ceramics using particles instead of surfactants as stabilizers of the wet foams. This method allows for the fabrication of ultra-stable wet foams that resist coarsening upon drying and sintering. Macroporous ceramics of various chemical compositions with open or closed cells, average cell sizes ranging from 10 to 300 ,m and porosities within 45% and 95%, can be easily prepared using this new approach. The sintered foams show high compressive strengths of up to 16 MPa in alumina foams with porosities of 88%. [source]