Chung Yuan Christian University

About: Chung Yuan Christian University is a education organization based out in Taoyuan City, Taiwan. It is known for research contribution in the topics: Membrane & Fuzzy logic. The organization has 9819 authors who have published 11623 publications receiving 213139 citations. The organization is also known as: Tiong-gôan-tāi-ha̍k & CYCU.

Anticorrosively Enhanced PMMA−Clay Nanocomposite Materials with Quaternary Alkylphosphonium Salt as an Intercalating Agent

Abstract: A series of polymer−clay nanocomposite (PCN) materials that consisted of poly(methyl methacrylate) (PMMA) and layered montmorillonite (MMT) clay were prepared by effectively dispersing the inorganic nanolayers of MMT clay in an organic PMMA matrix via in situ thermal polymerization. Organic methyl methacrylate monomers were first intercalated into the interlayer regions of organophilic clay hosts followed by a typical free radical polymerization. The as-synthesized PCN materials were characterized by infrared spectroscopy, wide-angle powder X-ray diffraction, and transmission electron microscopy. PCN coatings with low clay loading (e.g., 1 wt %) on cold-rolled steel were found much superior in anticorrosion over those of bulk PMMA based on a series of electrochemical measurements of corrosion potential, polarization resistance, corrosion current, and impedance spectroscopy in 5 wt % aqueous NaCl electrolyte. The molecular weights of PMMA extracted from PCN materials and bulk PMMA were determined by gel pe...

Free-Volume Depth Profile of Polymeric Membranes Studied by Positron Annihilation Spectroscopy: Layer Structure from Interfacial Polymerization

Abstract: The free-volume depth profile of asymmetric polymeric membrane systems prepared by interfacial polymerization is studied using positron annihilation spectroscopy coupled with a variable monoenergy slow positron beam. Significant variations of S, W, and R parameters from the Doppler broadened energy spectra vs positron incident energy up to 30 keV and orthopositronium lifetime and intensity are observed at different doping times of triethylenetetraamine (TETA) reacting with trimesoyl chloride (TMC) in an interfacial polymerization on modified porous polyacrylonitrile (PAN) asymmetric membrane. The positron annihilation data are analyzed in terms of free-volume parameters as a function of depth from the surface to nano- and micrometer regions of asymmetric membranes. A multilayer structure is obtained in polymerized polyamide (PA) on modified PAN membranes (m-PAN): a nanometer scale skin polyamide layer, a nanometer to micrometer scale transition layer from dense to porous m-PAN, and the porous m-PAN suppo...

High performance benzoxazine monomers and polymers containing furan groups

Abstract: Furan-containing benzoxazine monomers, 3-furfuryl-3,4-dihydro-2H-1,3-benzoxazine (P-FBz) and bis(3-furfuryl-3,4-dihydro-2H-1,3-benzoxazinyl)isopropane (BPA-FBz), were prepared using furfurylamine as a raw material. The chemical structures of P-FBz and BPA-FBz were characterized with FTIR, 1 H NMR, elemental analysis, and mass spectrometry. Formation of furfurylamine Mannich bridge networks in the polymerizations of P-FBz and BPA-FBz increased the cross-linking densities and thermal stability of the resulting polybenzoxazines. P-FBz- and BPA-FBz-based polymers also exhibited high glass transition temperatures above 300 °C, high char yields, and low flammability with limited oxygen index values of 31. The dielectric (D k = 3.21-3.39) and mechanical properties (high storage modulus of 3.0-3.9 GPa and low coefficient of thermal expansion of 37.7-45.4 ppm) of the P-FBz-and BPA-FBz-based polymers were superior or comparable to other polybenzoxazines.