Effect of rare earth nucleating agent on supercritical CO2 foaming behavior of block copolymerized polypropylene

2021 ◽  
pp. 026248932110536
Author(s):  
Yun Zhang ◽  
Yadong He ◽  
Chunling Xin ◽  
Yanbin Su
Keyword(s):  
Rare Earth ◽  
Saturation Temperature ◽  
Nucleating Agent ◽  
Expansion Ratio ◽  
Good Effect ◽  
Cell Diameter ◽  
Average Cell ◽  
Foaming Process ◽  
Foaming Temperature ◽  
Crystal Content

The rare earth nucleating agent was used to modify block copolymerized polypropylene (PPB) in foaming process. The results show that the crystallization of PPB and the melting temperature of β-crystal increased gradually with increased β-crystal nucleating agent content. The total crystallinity decreased with amount of addition increasing, and the relative content of β-crystal increased first and then decreased. When β-crystal nucleating agent content was 0.4 wt%, the relative β-crystal content reached the maximum value of 95.27%, and the final crystal grain refinement significantly. The addition of rare earth β-crystal nucleating agent has a good effect on improving the uniformity of foam cells. Under the same content of β-crystal nucleating agent and pressure, the average cell diameter and expansion ratio increased with the saturation temperature increasing. After the foaming temperature reaches 155°C, the expansion ratio began to decrease, which was also consistent with the changed trend of relative β-crystal content. At the same content of temperature and relative β-crystal, as the foaming pressure increased, the cell diameter decreased gradually, and the expansion ratio increased first, and then decreased.

Dynamic rheology and foaming behaviour of styrene–ethylene–butylene–styrene/ polystyrene blends

2016 ◽  
Vol 53 (4) ◽  
pp. 389-406 ◽  
Author(s):  
Ritima Banerjee ◽  
Suprakas Sinha Ray ◽  
Anup K Ghosh
Keyword(s):  
Volume Expansion ◽  
Complex Viscosity ◽  
Expansion Ratio ◽  
Dynamic Rheology ◽  
Blowing Agent ◽  
Foaming Process ◽  
Lower Volume ◽  
Foaming Temperature ◽  
And Storage ◽  
Nucleating Effect

Styrene–ethylene–butylene–styrene and its blends containing 10, 30 and 50 wt% polystyrene were subjected to batch foaming using physical blowing agent carbon dioxide. At higher foaming temperatures (80–110℃), complex viscosity ( η*) and storage modulus ( E′) were found to control the volume expansion ratio and the shrinkage of foams. For a given composition, optimal volume expansion was achieved at temperatures close to the glass transition temperature ( T g) of the polystyrene phase of that composition, indicating the presence of a complex viscosity window favourable for the foaming process. Blends with 30% and 50% polystyrene content possessed higher values of E′ and η*, and produced stable foams having higher volume expansion ratio, when foamed within their respective η* windows. At a much lower foaming temperature (35℃), polystyrene was found to have a nucleating effect. However, irrespective of rheological properties, all foams showed prominent shrinkage. A higher polystyrene content resulted in a lower volume expansion ratio, as well as shrinkage over a shorter period of time and a greater extent of shrinkage in the same time span. This can be attributed to the selective foaming of the ethylene–butylene phase, hindered by the stiff polystyrene aggregates.

Research on the Tensile Properties of Microcellular PS with Supercritical CO2

2013 ◽  
Vol 781-784 ◽  
pp. 395-402
Author(s):  
Xin Liao ◽  
Chang Chun Wang ◽  
Xiao Miao Cao
Keyword(s):  
Tensile Strength ◽  
Relative Density ◽  
Tensile Properties ◽  
Cell Diameter ◽  
Process Conditions ◽  
Structural Variable ◽  
Foaming Process ◽  
Theory Research ◽  
Foaming Temperature ◽  
Foaming Time

Separating the influence of relative density and cell diameter on the tensile properties is very important to the theory research on mechanic properties of microcellular foamed materials. In this article, differences of the influences of relative density and cell diameter on the tensile properties are identified by the foaming PS in constrained mold. The effects of relative density and foaming process conditions such as foaming temperature, foaming time and saturated pressure on the tensile strength and Youngs modulus are analyzed. The results show that relative density is the only structural variable of Youngs modulus and Youngs modulus is not relative to cell diameter. Youngs modulus is in proportion to relative density. Tensile stress of microcellular PS is in contrast to cell diameter, decreases with increasing foaming time and foaming temperature and increases with saturated pressure.

Microcellular Foaming of Biodegradable PLA/PPC Composite Using Supercritical CO2

2016 ◽  
Vol 861 ◽  
pp. 247-252
Author(s):  
Zhen Guo Ma ◽  
Xian Hua Lang ◽  
Peng Luo ◽  
Zhen Xiang Xin ◽  
Zhen Xiu Zhang
Keyword(s):  
Cell Structure ◽  
Saturation Pressure ◽  
Saturation Temperature ◽  
Poly Lactic Acid ◽  
Foam Density ◽  
Foaming Process ◽  
Composite Foams ◽  
Controlled Structure ◽  
Poly Propylene ◽  
Foaming Temperature

Poly (lactic acid) (PLA)/poly (propylene carbonate) (PPC) composite foams were microcellular foamed with CO2 through a batch foaming process. The influences of PPC contents, foaming temperature, and saturation pressure on the cell structure and foam density were investigated. The biodegradable PLA/PPC composite foam showed a controlled structure of microcellular and nanocellular. With an increase in saturation temperature and pressure, the cell size was increasing and both the cell density and foam density were decreased simultaneously.

scholarly journals Compression Molding of Thermoplastic Polyurethane Foam Sheets with Beads Expanded by Supercritical CO2 Foaming

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 656
Author(s):  
Tao Zhang ◽  
Seung-Jun Lee ◽  
Yong Hwan Yoo ◽  
Kyu-Hwan Park ◽  
Ho-Jong Kang
Keyword(s):  
Cell Size ◽  
Supercritical Co2 ◽  
Cell Structure ◽  
Thermoplastic Polyurethane ◽  
Compression Molding ◽  
Expansion Ratio ◽  
Compression Pressure ◽  
Elongation At Break ◽  
Foaming Process ◽  
Foaming Temperature

Expanded thermoplastic polyurethane (ETPU) beads were prepared by a supercritical CO2 foaming process and compression molded to manufacture foam sheets. The effect of the cell structure of the foamed beads on the properties of the foam sheets was studied. Higher foaming pressure resulted in a greater number of cells and thus, smaller cell size, while increasing the foaming temperature at a fixed pressure lowered the viscosity to result in fewer cells and a larger cell size, increasing the expansion ratio of the ETPU. Although the processing window in which the cell structure of the ETPU beads can be maintained was very limited compared to that of steam chest molding, compression molding of ETPU beads to produce foam sheets was possible by controlling the compression pressure and temperature to obtain sintering of the bead surfaces. Properties of the foam sheets are influenced by the expansion ratio of the beads and the increase in the expansion ratio increased the foam resilience, decreased the hardness, and increased the tensile strength and elongation at break.

Morphological evaluation of ultralow density microcellular foamed composites developed through CO2-induced solid-state batch foaming technique utilizing water as co-blowing agent

2019 ◽  
Vol 39 (4) ◽  
pp. 141-171 ◽  
Author(s):  
Rupesh Dugad ◽  
G Radhakrishna ◽  
Abhishek Gandhi
Keyword(s):  
Solid State ◽  
Saturation Pressure ◽  
Saturation Temperature ◽  
Acrylonitrile Butadiene Styrene ◽  
Expansion Ratio ◽  
Average Cell Size ◽  
Average Cell ◽  
Maximum Expansion ◽  
Blowing Agent ◽  
Batch Foaming

In this work, microcellular acrylonitrile-butadiene-styrene foams were developed with utilization of water as a co-blowing agent and CO2 as the primary blowing agent through the solid-state batch foaming process. The effect of saturation parameters with the content of the co-blowing agent has been studied extensively for various foaming attributes. The co-blowing agent enhanced the average cell size and the expansion ratio which are useful for better thermal insulation. The maximum expansion ratio of 29.9 obtained from the effect of saturation temperature and co-blowing agent, 23.6 from the effect of saturation pressure and co-blowing agent, and 22.4 from the effect of saturation time and co-blowing agent. The co-blowing agent significantly affects the cell morphology of polymeric foam with saturation parameters.

Foaming behavior of the fluorinated ethylene propylene copolymer assisted with supercritical carbon dioxide

2020 ◽  
pp. 0021955X2096400
Author(s):  
Zi-yin Jiang ◽  
Yun-fei Zhang ◽  
Chang-jing Gong ◽  
Zhen Yao ◽  
Abhinaya Shukla ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Saturation Pressure ◽  
Nucleating Agent ◽  
Expansion Ratio ◽  
Cell Diameter ◽  
Ethylene Propylene ◽  
Foaming Behavior ◽  
Fluorinated Ethylene Propylene ◽  
Supercritical Carbon

Foaming behavior of the fluorinated ethylene propylene copolymer (FEP) and its composites assisted with supercritical carbon dioxide (scCO2) as the blowing agent were investigated. The batch foaming process was applied at temperature ranging from 250°C to 265°C and pressure ranging between 12 MPa and 24 MPa. The optimal foaming temperature and saturation pressure were obtained for both pure FEP and FEP composites with 1 wt% different-sized BaTiO3 as nucleating agent. The cell diameter of pure FEP foam ranging from 80–140 µm was observed while the cell diameter decreased to 20–40 µm after adding BaTiO3 particles. The cell density of foamed FEP with BaTiO3 increased significantly from 106 to 108 cells/cm3 and the expansion ratio ranged between 4.0 and 5.5. Moreover, a decrease in an abnormal phenomenon that expansion ratio for the pure FEP foam was observed as the saturation pressure increased. This unexpected phenomenon can be explained by the relationship between foaming and crystallization coupling processes.

Experimental and numerical study of the polyurethane foaming process using high-pressure CO2

2020 ◽  
pp. 0021955X2097429
Author(s):  
Dongdong Hu ◽  
Chen Zhou ◽  
Tao Liu ◽  
Yichong Chen ◽  
Zhen Liu ◽  
...  
Keyword(s):  
Numerical Study ◽  
Cell Structure ◽  
Saturation Pressure ◽  
Gas Diffusion ◽  
Bubble Nucleation ◽  
Cell Diameter ◽  
Henry's Constant ◽  
Average Cell ◽  
Foaming Process ◽  
High Pressure Co2

A simulation of simultaneous bubble nucleation and growth was performed for polyurethane/CO2 physical foaming process. The single-factor and comprehensive effects of viscoelastic properties, Henry’s constant, CO2 diffusion coefficient and surface tension on the cell morphology were numerically analyzed. The results show that the cell density of PU foam ( N0) increases and its average cell diameter ( Dv) reduces with increased Henry’s constant and slower gas diffusion. Both N0 and Dv reduces with the curing degree ( α). In addition, the effects of α and foaming conditions on the cell structure were experimentally investigated. With an increase of α at foamable range, Dv decreases continuously and N0 increases first and then declines. With increasing saturation pressure and depressurization rate or decreasing temperature, N0 increases and Dv reduces. There is an intrinsic correlation between the simulated and experimental variables, and the results of the simulation and experiment are generally consistent.

Cell Structure Refining Mechanism of Pure Aluminum Foam with Fine Cell Structure

2013 ◽  
Vol 668 ◽  
pp. 37-41 ◽  
Author(s):  
Xiao Xu Luo ◽  
Xiao Qing Zuo ◽  
Yong Sheng Wang
Keyword(s):  
Aluminum Foam ◽  
Cell Structure ◽  
Pure Aluminum ◽  
Solid Particles ◽  
Cell Diameter ◽  
Average Cell ◽  
Foaming Agent ◽  
Aluminum Melt ◽  
Foaming Process ◽  
Decomposition Time

Cell structure refining mechanism of pure aluminum foam with fine cell structure has been studied. The results illustrate that the preparation of pure aluminum foam with fine cell structure is related to the following factors. Moderate melt viscosity is adopted to harmonize the relationship between the TiH2 dispersion and the bubble stabilization. When the stirring speed of stirring foaming process is 3000rpm, a more uniformed TiH2 dispersion in aluminum melt is expected, and bubbles are broken up to reduce the average cell diameter. Pre-oxidizing of foaming agent delays its starting decomposition time, hence to increase the dispersion uniform of foaming agent. Un-decomposed foaming agent or other solid particles, and initial bubbles in the aluminum melt can act as the nuclei of bubble heterogeneous nucleation. Increasing the uniformity of these initial bubbles and solid particles is helpful to fabricate pure aluminum foam with fine cell structure.

Preparation of Poly(Butylene succinate)(PBS) Foaming Materials

2011 ◽  
Vol 287-290 ◽  
pp. 1805-1810 ◽  
Author(s):  
Qiang Sun ◽  
Guan Bao Huang ◽  
Jun Hui Ji ◽  
Chang An Zhang
Keyword(s):  
Nucleating Agent ◽  
Expansion Ratio ◽  
Cellular Morphology ◽  
Butylene Succinate ◽  
Blowing Agent ◽  
One Step ◽  
Foaming Temperature ◽  
Foaming Technology ◽  
Morphology And Mechanical Properties ◽  
Foaming Time

Poly(butylene succinate)(PBS) is a kind of biodegradable materials. In this paper PBS foaming materials is prepared by physical foaming method of one-step compression molding. The influences of blowing agent and nucleating agent, the foaming temperature and foaming time on the cellular morphology of PBS foaming materials have been studied. The results showed that when the foaming temperature was 160°C，the blowing agent content was 5 parts, the foaming pressure was higher than 10 MPa, and the foaming time was 20 minutes with nucleating agent addition, the cellular morphology and mechanical properties of the foaming materials were better. The results showed that the foaming technology influenced greatly on the properties of foam of PBS materials. The expansion ratio had a small drop when the temperature increased. The addition of nucleator talc and foaming aids urea increased first then decreased the expansion ratio of the PBS foaming materials.

scholarly journals Effect of microstructure on the properties of polystyrene microporous foaming material

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 103-110
Author(s):  
Anfu Guo ◽  
Hui Li ◽  
Jie Xu ◽  
Jianfeng Li ◽  
Fangyi Li
Keyword(s):  
Thermal Conductivity ◽  
Compression Modulus ◽  
Cell Diameter ◽  
Compressive Property ◽  
Strength Increase ◽  
Compression Performance ◽  
Negative Linear Correlation ◽  
Sample Density ◽  
Foaming Temperature ◽  
The Relationship

AbstractThe performance of Polystyrene microporous foaming (PS-MCF) materials is influenced by their microstructures. Therefore, it is essential for industrializing them to investigate the relationship between their microstructure and material properties. In this study, the relationship between the microstructure, compressive property, and thermal conductivity of the PS-MCF materials was studied systematically. The results show that the ideal foaming pressure of PS-MCF materials, obtaining compression performance, is around 20 MPa. In addition, the increase of temperature causes the decrease of sample density. It effects that the compression modulus and strength increase with the decrease of foaming temperature. Because the expansion rate and cell diameter of the PS-MCF materials reduce the thickness of cell wall, they are also negatively correlated with their mechanical properties. Moreover, there is a negative linear correlation between the thermal conductivity and cell rate, whereas the cell diameter is positively correlated with the thermal conductivity.

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