Formation Mechanism of Bi-modal Cell Structure Polystyrene Foams by Synergistic Effect of CO2-philic Additive and Co-blowing Agent

2021 ◽  
pp. 105498
Author(s):  
Dongdong Hu ◽  
Xiulu Gao ◽  
Wei Qiang ◽  
Liyun Cui ◽  
Zhimei Xu ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Formation Mechanism ◽  
Cell Structure ◽  
Blowing Agent

scholarly journals Microstructural and Chemical Analysis of Polyurethane and Polyisocyanurate Foam Insulations

2021 ◽  
Author(s):  
Umberto Berardi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Performance ◽  
Cell Structure ◽  
Polymer Degradation ◽  
Chemical Characterization ◽  
Aging Behavior ◽  
Blowing Agent ◽  
Closed Cell ◽  
Physical Attributes ◽  
Cell Foam

For some closed cell foam insulation products, the thermal conductivity increases at low temperatures, contrary to single thermal resistance values provided by manufacturers. This phenomenon has been demonstrated in various polyurethane and polyisocyanurate insulations. The reduction in thermal performance has been attributed to the diffusion of air and blowing agent through the foam and to the condensation of blowing agent. Aging processes such as freeze-thaw cycling, moisture accumulation, and polymer degradation further increase thermal conductivity. The initial cell structure plays a role in dictating the thermal performance. To further understand the loss of thermal performance in closed cell foams, microstructure and chemical characterization was performed in this study. The aging behavior of foam insulations was analyzed by imaging foams with SEM and by measuring foam. Changes in the polymer physical attributes were identified and compared to increases in thermal conductivity. This project also used gas chromatography and quantified changes in pentane concentration in polyisocyanurate foams that have undergone aging

Synergistic effect of a crystal modifier and screw dislocation step defects on the formation mechanism of nickel micro-nanocone

2019 ◽  
Vol 245 ◽  
pp. 68-72 ◽  
Author(s):  
Ehsan Rahimi ◽  
Ali Rafsanjani-Abbasi ◽  
Amin Imani ◽  
Ali Reza Kiani Rashid ◽  
Saman Hosseinpour ◽  
...  
Keyword(s):  
Synergistic Effect ◽  
Screw Dislocation ◽  
Formation Mechanism

The Effects of Henna Fillers on the Properties of Polyurethane Foam Composites

2020 ◽  
Vol 1010 ◽  
pp. 520-525
Author(s):  
Sinar Arzuria Adnan ◽  
Firuz Zainuddin ◽  
Nur Hidayah Ahmad Zaidi ◽  
Nur Afikah Zulkeply ◽  
Nur Maizatul Shima Adzali ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Cell Wall ◽  
Water Absorption ◽  
Cell Structure ◽  
Natural Fibers ◽  
Diphenylmethane Diisocyanate ◽  
Core Density ◽  
Blowing Agent ◽  
Pu Foam ◽  
Absorption Percentage

Polyurethane (PU) foam were produced from polyol (PolyGreen R3110) and 4,4- diphenylmethane diisocyanate (Maskiminate 80) with distilled water as a blowing agent. Natural fibers have received more attention from researchers due to their ability to increase the properties of the polymer composites. In this work, PU/Henna foam composites were prepared by used Henna fibers at different loading of 5, 10, 15 and 20 wt. %. The effect of different Henna loading on PU foam were investigated by density, compression test, morphology and water absorption. Core density of PU/Henna foam composites increased with addition Henna compared to control PU and showed highest core density of 85.10 kgm-3. Compressive strength decreased to 0.53 MPa after Henna addition at 5 % PU/Henna foam composites. Henna addition to 20 % PU/Henna foam composites were reduced the compressive strength to 0.97 MPa due to stiffness effect of Henna that contributed to embrittlement of the cell wall. The distorted cell wall and less uniform of cell structure were proved by SEM due to Henna addition as compared to control PU. Water absorption percentage of PU/Henna foam composites were increased with Henna addition as compared to control PU. It is because hydrophilic properties of Henna tendency to absorb moisture.

scholarly journals CaCO3 blowing agent mixing method for biomass composites improved buffer packaging performance

RSC Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2501-2511
Author(s):  
Kai-qiang Sun ◽  
Fang-yi Li ◽  
Jian-yong Li ◽  
Jian-feng Li ◽  
Chuan-wei Zhang ◽  
...  
Keyword(s):  
Cell Structure ◽  
Packaging Materials ◽  
Open Cell ◽  
Blowing Agent ◽  
Biodegradable Composites ◽  
Mixing Method

Biodegradable composites with an open-cell structure were developed to replace petroleum-based buffer packaging materials.

Foaming of CNTs/PMMA Nanocomposite with Supercritical Carbon Dioxide

2012 ◽  
Vol 508 ◽  
pp. 61-64 ◽  
Author(s):  
Yuan Lu Xiong ◽  
Qiang Shen ◽  
Huan Yuan ◽  
Fei Chen ◽  
Guo Qiang Luo
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Cell Density ◽  
Cell Structure ◽  
Cell Distribution ◽  
Emi Shielding ◽  
Blowing Agent ◽  
Foaming Process ◽  
Nanocomposite Foams ◽  
Supercritical Carbon

The CNTs/PMMA Nanocomposite Foams Are a Kind of Novel Multifunctional Foams which Have a Potential Application for Lightweight Conductive and EMI Shielding Materials. In this Work, the CNTs/PMMA Nanocomposite Foams with Different CNTs Contents from 1wt.% to 10wt.% Were Prepared at a Temperature Range of 50-140 °C with Supercritical Carbon Dioxide as Blowing Agent. The Results Suggest that the Fully Heterogeneous Nucleation Is Achieved due to the Contribution of Well-Dispersed CNTs in PMMA. The CNTs/PMMA Nanocomposite Foams Exhibit a Uniform Cell Distribution, and the Cell Density Is Two Orders of Magnitude Higher than that of PMMA Foams. The Cell Size and Cell Density of CNTs/PMMA Nanocomposite Foams Could Be Controlled by Adjusting the Foaming Process and CNTs Contents. It Is Also Suggested that the Foaming Process Plays an Important Role on the Cell Structure Rather than that of CNTs Content when it Is Higher than 1wt.%.

Morphological Changes of Irradiated PMMA via Supercritical Carbon Dioxide Treatments

2011 ◽  
Vol 239-242 ◽  
pp. 1510-1514
Author(s):  
Xin Long Ling ◽  
Zhong Feng Tang ◽  
Shi Rong Huang
Keyword(s):  
High Cell Density ◽  
Morphological Changes ◽  
Cell Structure ◽  
High Cell ◽  
Blowing Agent ◽  
Closed Cell ◽  
Morphology And Structure ◽  
Γ Ray ◽  
Effects Of Radiation ◽  
Quench Method

Poly (methyl methacrylate) (PMMA) sheets were radiated by60Co γ-ray in air and then irradiated PMMA foams were successfully prepared by supercritical CO2(SC CO2) as a physical blowing agent via pressure quench method. The effects of radiation dose on the cell morphology and structure of the obtained foams were studied. The results showed that the foams possessed spherically closed cell structure with uniform cell size. The γ-ray irradiated PMMA sheets had a high cell density than those virgin PMMA.

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