Solubility and diffusivity of CO2 and N2 in TPU and their effects on cell nucleation in batch foaming

2019 ◽  
Vol 154 ◽  
pp. 104623 ◽  
Author(s):  
Ruosong Li ◽  
Jung Hyub Lee ◽  
Chongda Wang ◽  
Lun Howe Mark ◽  
Chul B. Park
Keyword(s):  
Cell Nucleation ◽  
Batch Foaming

scholarly journals Effect of Compatibility on the Foaming Behavior of Injection Molded Polypropylene and Polycarbonate Blend Parts

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 300 ◽  
Author(s):  
Bei Su ◽  
Ying-Guo Zhou ◽  
Bin-Bin Dong ◽  
Cao Yan
Keyword(s):  
Morphological Structure ◽  
Potential Method ◽  
Grafted Polymers ◽  
Dynamic Mechanical Analyzer ◽  
Blowing Agent ◽  
Cell Nucleation ◽  
Foaming Behavior ◽  
Thermal Features ◽  
Injection Molded ◽  
Scanning Electron

To improve the foaming behavior of a common linear polypropylene (PP) resin, polycarbonate (PC) was blended with PP, and three different grafted polymers were used as the compatibilizers. The solid and foamed samples of the PP/PC 3:1 blend with different compatibilizers were first fabricated by melt extrusion followed by injection molding (IM) with and without a blowing agent. The mechanical properties, thermal features, morphological structure, and relative rheological characterizations of these samples were studied using a tensile test, dynamic mechanical analyzer (DMA), scanning electron microscope (SEM), and torque rheometer. It can be found from the experimental results that the influence of the compatibility between the PP and PC phases on the foaming behavior of PP/PC blends is substantial. The results suggest that PC coupling with an appropriate compatibilizer is a potential method to improve the foamability of PP resin. The comprehensive effect of PC and a suitable compatibilizer on the foamability of PP can be attributed to two possible mechanisms, i.e., the partial compatibility between phases that facilitates cell nucleation and the improved gas-melt viscosity that helps to form a fine foaming structure.

A study of cell nucleation in the extrusion of polypropylene foams

1997 ◽  
Vol 37 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Chul B. Park ◽  
Lewis K. Cheung
Keyword(s):  
Cell Nucleation

A Comparison of CO2 and N2 Foaming Behaviors of PP in a Visualization System

2020 ◽  
Vol 35 (5) ◽  
pp. 503-517
Author(s):  
Q.-P. Guo ◽  
J. Wang ◽  
C. B. Park
Keyword(s):  
Cell Density ◽  
Nucleating Agent ◽  
Gas Content ◽  
Experimental Conditions ◽  
Maximum Cell Density ◽  
Visualization System ◽  
Cell Nucleation ◽  
Processing Strategies ◽  
Automotive Parts ◽  
Maximum Cell

Abstract Understanding of polypropylene (PP) foaming is critically important to reduce the weight of automotive parts. In this study, we used a batch foaming simulation system with visualization cell, to observe the foaming behaviors of PP that is blown with CO2 and N2 under various experimental conditions. We found that the nucleating agent content, initial temperature, pressure (i. e., gas content), and pressure drop rate during foaming have a significant effect on cell nucleation and cell growth. The cell density and the void fraction of PP foamed with CO2 and N2, respectively, were separately observed and compared. It was found that under the same experimental conditions, the maximum cell density of PP foamed with CO2 was higher than that of PP foamed with N2. However, the maximum cell density of PP foamed with CO2 was determined to be lower than that of PP foamed with N2, when the same gas mole numbers were employed. Based on the experimental results, optimum foaming conditions and effective processing strategies for PP-CO2 system are suggested.

A novel lab-scale batch foaming equipment: The mini-batch

2016 ◽  
Vol 52 (5) ◽  
pp. 533-543 ◽  
Author(s):  
D Tammaro ◽  
V Contaldi ◽  
MG Pastore Carbone ◽  
E Di Maio ◽  
S Iannace
Keyword(s):  
Batch Foaming

Nocardia effects in waste activated sludge

1998 ◽  
Vol 38 (2) ◽  
pp. 49-54 ◽  
Author(s):  
Krishna R. Pagilla ◽  
David Jenkins ◽  
Wendell Kido
Keyword(s):  
Activated Sludge ◽  
Foam Stability ◽  
Anaerobic Digester ◽  
Waste Activated Sludge ◽  
Dissolved Air Flotation ◽  
Anaerobic Digesters ◽  
Primary Sludge ◽  
Mixed Liquor ◽  
Dissolved Air ◽  
Batch Foaming

Two effects of Nocardia in waste activated sludge (WAS) were investigated: (i) the influence of WAS in the solids treatment recycle streams on Nocardia persistence in the activated sludge, and (ii) the effect of Nocardia in WAS on anaerobic digester foaming. About 4% of the Nocardia present in the mixed liquor was due to seeding from the WAS solids in the dissolved air flotation thickener recycle stream recycle. Nocardia filaments in WAS at levels of between 104 to 106 intersections/g VSS resulted in Nocardia levels of approximately 104 to 105 intersections/g VSS in anaerobic digesters that treated both WAS and primary sludge. The effect of disinfecting these Nocardia filaments in the WAS with Cl2 was investigated at Cl2 dose ranges of 20-60 mg Cl2/l WAS and 100-200 mg Cl2/l WAS on a lab scale using batch foaming tests to assess success. Chlorination with 20 - 60 mg Cl2/l WAS approximately doubled both sludge foaming potential and foam stability. At Cl2 doses of 100-200 mg Cl2/l WAS, foaming potential was increased almost 10-fold, and foam stability was increased by 2.5 times. These results indicate that chlorination of WAS feed to an anaerobic digester for inactivation of Nocardia should not be practiced.

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