Cell nucleation in dominating formation of bimodal cell structure in polypropylene/polystyrene blend foams prepared via continuous extrusion with supercritical CO2

2016 ◽  
Vol 110 ◽  
pp. 65-74 ◽  
Author(s):  
Kun Wang ◽  
Yongyan Pang ◽  
Fei Wu ◽  
Wentao Zhai ◽  
Wenge Zheng
Keyword(s):  
Supercritical Co2 ◽  
Cell Structure ◽  
Cell Nucleation ◽  
Continuous Extrusion

scholarly journals Role of Wood Fibers in Tuning Dynamic Rheology, Non-Isothermal Crystallization, and Microcellular Structure of Polypropylene Foams

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 106 ◽  
Author(s):  
Yongming Song ◽  
Youyong Wang ◽  
Hao Li ◽  
Qiling Zong ◽  
Ailing Xu
Keyword(s):  
Isothermal Crystallization ◽  
Fiber Composite ◽  
Cell Structure ◽  
Wood Fiber ◽  
Crystallization Rate ◽  
Complex Viscosity ◽  
Expansion Ratio ◽  
Wood Fibers ◽  
Cell Nucleation ◽  
Composite Foams

Microcellular polypropylene (PP)/wood fiber composite foams were fabricated via batch foaming assisted by supercritical CO2 (scCO2). Effects of wood fibers on rheology, crystallization, and foaming behaviors of PP were comprehensively investigated. The obtained results showed that the incorporation of wood fibers increased the complex viscosity and the storage modulus of the PP matrix. Jeziorny’s model for non-isothermal crystallization kinetics indicated that wood fibers did not change the crystal growth. However, the crystallization rate of the PP matrix was decreased to a certain extent with increasing wood fiber loadings. The wood fiber exerts a noticeable role in improving the cell density and reducing the cell size, despite decreasing the expansion ratio. Interestingly, a “small-sized cells to large-sized cells” gradient cell structure was found around the wood fibers, implying cell nucleation was induced at the interface between wood fiber and PP matrix. When wood fiber loadings were specifically increased, a desirable microcellular structure was obtained. However, further increasing the wood fiber loadings deteriorated the cell structure. Moreover, the crystallinity of the composite foams initially decreased and then slightly increased with increasing wood fiber loadings, while the crystal size decreased.

Effect of Plasticizer (DOP) on Cell Structure and Mechanical Properties of Extrusion-Foamed PVC Sheet

2015 ◽  
Vol 815 ◽  
pp. 601-606 ◽  
Author(s):  
Ming Yi Wang ◽  
Nan Qiao Zhou ◽  
Jun Hu
Keyword(s):  
Mechanical Properties ◽  
Cell Structure ◽  
Dioctyl Phthalate ◽  
Bubble Coalescence ◽  
Low Density ◽  
Foaming Agent ◽  
Elongation At Break ◽  
Foaming Process ◽  
Continuous Extrusion ◽  
Scanning Electron

Using supercritical CO2 as the foaming agent, rigid polyvinyl chloride (R-PVC) foam sheets were prepared in a continuous extrusion foaming system. The effects of dioctyl phthalate (DOP) on the rheological properties of PVC were investigated using a Brabender torque rheometer while other basic formula remained unchanged. The influences of DOP content on microstructure, mechanical properties and density of PVC micro foamed sheet were investigated with scanning electron microscopy (SEM). The results showed that the addition of DOP resulted in increased flexibility and the elongation at break of the foamed PVC sheet, while the mechanical properties of foamed PVC sheet decreased with the increase of DOP content, implying that excessive addition of DOP will cause gas escape and bubble coalescence in the foaming process. Low density PVC foam sheets with fine cell morphology were obtained when 2 phr DOP was added in PVCformula.

The synergy of supercritical CO2 and supercritical N2 in foaming of polystyrene for cell nucleation

2014 ◽  
Vol 90 ◽  
pp. 35-43 ◽  
Author(s):  
Anson Wong ◽  
Lun Howe Mark ◽  
Mohammad M. Hasan ◽  
Chul B. Park
Keyword(s):  
Supercritical Co2 ◽  
Cell Nucleation

Cell Structure Evolution and the Crystallization Behavior of Polypropylene/Clay Nanocomposites Foams Blown in Continuous Extrusion

2010 ◽  
Vol 49 (20) ◽  
pp. 9834-9845 ◽  
Author(s):  
Wentao Zhai ◽  
Takashi Kuboki ◽  
Lilac Wang ◽  
Chul B. Park ◽  
Eung K. Lee ◽  
...  
Keyword(s):  
Crystallization Behavior ◽  
Cell Structure ◽  
Structure Evolution ◽  
Clay Nanocomposites ◽  
Continuous Extrusion
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