Correlation of Decompression Time and Foaming Temperature on the Cell Density of Foamed Polystyrene

2005 ◽  
Vol 24 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Keiichi Muratani ◽  
Minoru Shimbo ◽  
Yasushi Miyano
Keyword(s):  
Cell Growth ◽  
Temperature Dependence ◽  
Cell Density ◽  
Saturation State ◽  
Foaming Agent ◽  
Decompression Rate ◽  
Cell Nucleation ◽  
Cell Densities ◽  
Foaming Temperature ◽  
Decompression Time

In this paper, the correlation between the foaming temperature and the decompression rate (decompression time) of the cell density that is the number of cells per unit volume remaining in the foamed plastic will be discussed. Foaming was carried out by the following method: the blowing agent was soaked into the resin as a solid state at high pressure under temperatures higher than the glass transition temperature of the resin. After the foaming agent reached its saturation state, cell nucleation and cell growth were accelerated by decompression. Finally, cell growth was halted by cooling. A device that can accurately control temperature and the decompression rate was designed, produced and verified for accuracy prior to this investigation. The polystyrene (PS) specimens were foamed under various foaming temperatures and the decompression rates using the above-mentioned method. The following results were obtained: 1. Cell density of foamed polystyrene shows time and temperature dependence as follows. The cell density increases when the decompression rate is quick, i.e. the decompression time is shortened under the condition of low foaming temperature, and cell density decreases when the decompression rate is slow, i.e. decompression time is lengthened under the condition of high foaming temperature, 2. Correlation is maintained between the temperature dependence and time dependence of the cell density of foamed PS, and it can be expressed by one master curve, 3. Based on this correlation, it is possible to predict the required foaming conditions of plastics having arbitrary cell densities.

Effect of Saturation Pressure on Equivalency of Decompression Time and Foaming Temperature on Cell Density of Foamed Polystyrene

2007 ◽  
Vol 26 (5) ◽  
pp. 295-304 ◽  
Author(s):  
Susumu Nakano ◽  
Minoru Shimbo ◽  
Akihiro Misawa
Keyword(s):  
Cell Growth ◽  
Temperature Dependence ◽  
Cell Density ◽  
Saturation Pressure ◽  
Temperature Shift ◽  
Shift Factor ◽  
Saturation State ◽  
Decompression Rate ◽  
Foaming Temperature ◽  
Decompression Time

In this paper, the effect of saturation pressure on the time-temperature equivalent law of the decompression rate (decompression time) and foaming temperature of the cell density, the number of cells per unit volume remaining in foamed plastic was discussed. The foaming was carried out in the method described be by using batch foaming process. The blowing agent was soaked into the resin as a solid state at various high saturation pressures under temperatures higher than the glass transition temperature of the resin. After foaming agent reached its saturation state, cell nucleation and cell growth were accelerated by decompression. Finally, cell growth was halted by cooling. The polystyrene (PS) specimens were foamed under the various saturation pressures, foaming temperatures and decompression rates. The following results were obtained. (1) Cell density of foamed PS shows time and temperature dependence as follows. The cell density increases when the decompression rate is quick, i.e. the decompression time is shortened at the condition of low foaming temperature, and cell density decreases when the decompression rate is slow, i.e. decompression time is lengthened at the condition of high foaming temperature under various saturation pressures. (2) The time-temperature equivalent law is maintained between the time dependence and temperature dependence of the cell density of foamed PS, and it can expressed with the same time-temperature shift factor if the decompression rate is the same even if saturation pressure changes.

The Influence of Technological Conditions on Cell Density and Cell Morphology of PPESK Microporous Material

2013 ◽  
Vol 423-426 ◽  
pp. 507-510
Author(s):  
Min Jie Qu ◽  
Tian Qi Li ◽  
Lai Jiu Zheng ◽  
Shi Yang Zhu ◽  
Ling Ling He ◽  
...  
Keyword(s):  
High Temperature ◽  
Cell Density ◽  
Cell Morphology ◽  
Saturation Pressure ◽  
Microporous Material ◽  
Foaming Agent ◽  
Temperature Resistance ◽  
Engineering Plastic ◽  
High Temperature Resistance ◽  
Foaming Temperature

Phthalazinone structure contained phthalaazione ether sulfone ketone (PPESK) is a kind of excellent engineering plastic with high temperature resistance and resolvability. In this paper, SC-CO2was used as foaming agent to prepare PPESK foams by temperature rising method. The influence of technological conditions like foaming time, foaming temperature and saturation pressure on cell density and cell morphology was discussed and analyzed.

Foaming of Polystyrene with Supercritical Carbon Dioxide

2013 ◽  
Vol 669 ◽  
pp. 366-370
Author(s):  
Wei Hua Ma ◽  
Jie Ding ◽  
Qin Zhong
Keyword(s):  
Carbon Dioxide ◽  
Glass Transition ◽  
Supercritical Carbon Dioxide ◽  
General Purpose ◽  
High Impact ◽  
Foaming Process ◽  
Cell Nucleation ◽  
Cell Densities ◽  
Foaming Temperature ◽  
Supercritical Carbon

General Purpose Polystyrene (GPPS) and High Impact Polystyrene (HIPS) were foamed with supercritical carbon dioxide in the batch foaming process. Foaming behaviors of GPPS and HIPS were investigated. The cell diameters and cell densities of GPPS and HIPS vary strangely with foaming conditions and can be explained by the classical nucleation. The competition between cell growth and cell nucleation is used to explain these strange foaming behaviors. The glass transition temperature (Tg) almost remains constant with the foaming temperature rising.

Preparation of a Novel Cellular Fiber: Control of Cell Density of the Fiber

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Guo Linfeng ◽  
Chunyan Xiong ◽  
Jiangjiang Zhu ◽  
Yimin Wang
Keyword(s):  
Cell Density ◽  
Cellular Structure ◽  
Processing Parameters ◽  
High Density ◽  
Great Promise ◽  
Saturation Time ◽  
System A ◽  
Cell Densities ◽  
Poly Ethylene ◽  
Foaming Temperature

AbstractA new cellular fiber was obtained by a post-treatment of spun fibers. Cellular polymers such as poly(ethylene terephthalate) show great promise for different engineering applications due to their high density property. Recent study has shown that some high density cellular polymers possess long fatigue life and/or equivalent strengths as compared with commercial-type neat polymers. However, only few studies have focused on the process of cellular polymer fibers to date. In this paper, the effect on a cellular structure of cellular PET fibers (hereafter called “CPET fibers”) subjected to different forming processes is discussed. An ultra saturating gas method was used to fabricate the CPET fibers with different cell densities. Inert gas nitrogen (N2) was saturated in PET fiber at high pressure to form a polymer/gas system. A pressure vessel was then discharged and polymer/gas solutions were foamed at a temperature controlled medium. The effect on the fiber’s cellular structure, particularly on the fiber cell density with different processing parameters such as pressure, saturation time, foaming temperature and time was investigated in detail. Experimental results showed that the cell density of the CPET fibers increased with increasing the pressure, saturation time, foaming temperature and time. The saturation time and pressure are key factors that affect the density of cells formed inside the CPET fibers. The foaming time however showed no substantial influence on the cell density of the fibers when held longer than 10s.

scholarly journals The effect of foaming agent on mechanical and physical properties of Polypropylene

2018 ◽  
Vol 2 (1) ◽  
Author(s):  
SEDEF CAKIR 1 ◽  
MUHAMMED AYCICEK 1 ◽  
EDIZ ALTUN 2 ◽  
Akin Akinci 1
Keyword(s):  
Mechanical Properties ◽  
Cell Density ◽  
Cell Morphology ◽  
Injection Pressure ◽  
Skin Layer ◽  
Polymer Materials ◽  
Cell Diameter ◽  
Melt Temperature ◽  
Foaming Agent ◽  
Foaming Agents

In this study, Polypropylene (PP) foam materials were used with injection parameters such as melting, molding and injection temperatures. To produce foam materials, chemical foaming agents were used, and added to polymer materials as 1wt.%, 1.5wt.%, 2wt.%, 2.5wt.%, 3wt.%. The mechanical properties of foam samples were determined based on the parameters. Cell morphology characterization such as cell diameter, cell count, skin layer thickness and cell density, and mechanical properties such as tensile and impact strength of polymer foams were examined.Generally, the closed-cell foam structure was obtained. The most important parameters affecting the cell morphology have been injection pressure, melt temperature and amount of foaming agent. With increasing the amount of foaming agent, cell density increased, foam density and mechanical properties decreased.

scholarly journals Effect of Cell Density on the Removal of Microcystis by Coagulation

2020 ◽  
Vol 42 (6) ◽  
pp. 319-326
Author(s):  
Joo Eun Han ◽  
Wontae Lee
Keyword(s):  
Surface Water ◽  
Chlorophyll A ◽  
Cell Density ◽  
Target Cell ◽  
Removal Rate ◽  
Nakdong River ◽  
Removal Rates ◽  
Cell Densities

Objectives:This study evaluated the removal of <i>Microcystis</i> by coagulation in raw waters with three different cell densities.Methods:Raw waters were prepared at three different cell densities (target cell densities of 10,000, 100,000, and 1,000,000 cell/mL; actual cell densities of 9,950, 102,000, and 991,000 cell/mL) by adding <i>Microcystis</i> into surface water from Nakdong river. Jar-tests were conducted with PACL, alum, illite, and loess at dosages of 0-150 mg/L.Results and Discussion:Regardless of coagulant types, the removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. PACl and alum exhibited higher removal rates than illite and loess; PACl was the best coagulant to remove <i>Microcystis</i>. Removal of chlorophyll-a was highest when PACl added at 20.4 mg/L, and no significant increase in removal rate was observed with higher dosages of PACl. However, removal rates of chlorophyll-a by illite and loess gradually increased as the dosages increased.Conclusions:With the coagulants tested in this study, removal rates of <i>Microcystis</i> increased as the coagulant dosages increased. Removal rates of <i>Microcystis</i> increased as the cell densities increased probably because <i>Microcystis</i> acted as particles which could enhance the coagulation efficiency.

scholarly journals Cell density-dependent stimulation of PAI-1 and hyaluronan synthesis by TGF-β in orbital fibroblasts

2016 ◽  
Vol 229 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Erika Galgoczi ◽  
Florence Jeney ◽  
Annamaria Gazdag ◽  
Annamaria Erdei ◽  
Monika Katko ◽  
...  
Keyword(s):  
Cell Density ◽  
Inverse Correlation ◽  
Fold Increase ◽  
Dermal Fibroblasts ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Density Dependent ◽  
Cell Densities ◽  
Orbital Fibroblasts ◽  
Pai 1

During the course of Graves’ orbitopathy (GO), orbital fibroblasts are exposed to factors that lead to proliferation and extracellular matrix (ECM) overproduction. Increased levels of tissue plasminogen activator inhibitor type 1 (PAI-1 (SERPINE1)) might promote the accumulation of ECM components. PAI-1 expression is regulated by cell density and various cytokines and growth factors including transforming growth factorβ(TGF-β). We examined the effects of increasing cell densities and TGF-β on orbital fibroblasts obtained from GO patients and controls. Responses were evaluated by the measurement of proliferation, PAI-1 expression, and ECM production. There was an inverse correlation between cell density and the per cell production of PAI-1. GO orbital, normal orbital, and dermal fibroblasts behaved similarly in this respect. Proliferation rate also declined with increasing cell densities. Hyaluronan (HA) production was constant throughout the cell densities tested in all cell lines. In both GO and normal orbital fibroblasts, but not in dermal fibroblasts, TGF-β stimulated PAI-1 production in a cell density-dependent manner, reaching up to a five-fold increase above baseline. This has been accompanied by increased HA secretion and pericellular HA levels at high cell densities. Increasing cell density is a negative regulator of proliferation and PAI-1 secretion both in normal and GO orbital fibroblasts; these negative regulatory effects are partially reversed in the presence of TGF-β. Cell density-dependent regulation of PAI-1 expression in the orbit, together with the local cytokine environment, may have a regulatory role in the turnover of the orbital ECM and may contribute to the expansion of orbital soft tissue in GO.

Amino acid uptake regulation by cell growth in cultured hepatocytes isolated from fetal and adult rats

1992 ◽  
Vol 12 (2) ◽  
pp. 135-141 ◽  
Author(s):  
S. Leoni ◽  
S. Spagnuolo ◽  
M. Massimi ◽  
F. Terenzi ◽  
L. Conti Devirgiliis
Keyword(s):  
Amino Acid ◽  
Cell Growth ◽  
Growth Inhibition ◽  
Cell Density ◽  
Amino Acid Uptake ◽  
Growth Stimulation ◽  
Acid Uptake ◽  
Adult Rats ◽  
Dependent Growth ◽  
Differentiation Stage

Amino acid uptake mediated by system A was studied in cultured fetal and adult hepatocytes, subjected to growth stimulation by EGF and insulin, or to growth inhibition by high cell density. The mitogenic stimulation induced a strong transport increase only in fetal cells, while the cell density-dependent growth inhibition, probably mediated by molecules present on adult hepatocyte membranes, provoked the decrease of amino acid uptake only in the adult cells. The results indicate that the different modulation of amino acid transport by cell growth is dependent on the age and the differentiation stage of hepatocytes.

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