Controlling the foam morphology of supercritical CO2-processed poly(methyl methacrylate) with CO2-philic hybrid nanoparticles

Highly CO2-philic nanoparticles, octatrimethylsiloxy polyhedral oligomeric silsesquioxanes (POSS) are used to increase the affinity of poly(methyl methacrylate) (PMMA) to CO2 in supercritical carbon dioxide (scCO(2)) foaming, thus to improve its foaming performance and the foam morphology. PMMA and PMMA-POSS composite foams were produced based on the two-factorial design, at the upper and lower experimental conditions of pressure, temperature, processing time, and venting rate. The foams of PMMA-5% POSS composites exhibited smaller average pore sizes and higher pore densities than neat PMMA and PMMA-0.5% POSS composites. The smallest average pore diameter (0.3 mu m) and the highest pore density (6.33 x 10(12) cm(-3)) were obtained with this composite processed at 35 degrees C, 32 MPa, for 24 h and depressurized with fast-venting rate (0.4 MPa/s). ScCO2 processing decreased the density of the polymer by more than 50%.


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Polymer blends based on poly(ethylene glycol), polyacrylonitrile, and multiwalled carbon nanotubes (MWNTs) were prepared by the solvent cast technique from the dispersion of the MWNTs in the concentration range 0-3.45 wt %. The interaction of the MWNTs with the polymer blend was confirmed by a Fourier transform infrared (FTIR) spectroscopy study. The thermal properties of the polymer blend with the MWNTs were carried out by means of differential scanning calorimetry (DSC). It was evident from DSC that the p...
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A combinatorial approach is used to investigate several bimetallic catalytic systems and the promoter effect on these catalysts to develop highly active and selective catalysts for direct epoxidation of propylene to propylene oxide (PO) using molecular oxygen. 2%Cu/5%Ru/c-SiO2 catalyst yielded the highest performance with high propylene conversion and PO selectivity among the bimetallic catalytic systems including silver, ruthenium, manganese and copper metals. On the other hand, the most effective catalyst...
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Formability of AZ31 Magnesium alloy has certain limits below 200 ℃ and depends strongly on temperature, due to the strain localization and shear banding associated with the twinning activity. In this thesis, magnesium sheets with basal, off-basal (90° tilted) and mixed (50% basal + 50% off-basal) textures are rolled between room temperature and 165 ℃ to understand and control the twinning-induced localizations. By increasing strain from 0.1 to 0.6 and raising the temperature, the fraction of flow localized ...
Citation Formats
M. Özkutlu Demirel, G. Bayram, and Ç. Dilek Hacıhabiboğlu, “Controlling the foam morphology of supercritical CO2-processed poly(methyl methacrylate) with CO2-philic hybrid nanoparticles,” JOURNAL OF APPLIED POLYMER SCIENCE, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: