Synthesis and Characterization of Polyimide with High Blackness and Low Thermal Expansion by Introducing 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole-Based Chromophores.

The market demand for black polyimide (BPI) has grown hugely in the field of flexible copper-clad laminates (FCCLs) as a replacement for transparent yellow polyimide. The 3,6-bis(thiophen-2-yl)diketopyrrolopyrroles (TDPP) derivative is recognized for its high molar extinction coefficient. In this research, we have synthesized a diamine monomer named 3,6-bis[5-(4-amino-3-fluorophenyl)thiophen-2-yl]-2,5-bis(2-ethylhexyl)pyrrolo[4,3-c]pyrrole-1,4-dione (DPPTENFPDA), featuring a TDPP unit attached by fluorinated benzene rings.

The Effect of Molecular Isomerism on the Barrier Properties of Polyimides: Perspectives from Experiments and Simulations.

A novel carbazole-containing diamine (M-2,7-CPDA) isomer of our previously reported diamine 2,7-CPDA, has been synthesized using a two-step synthesis. Compared with 2,7-CPDA, the substituted position of amino is changed from to for M-2,7-CPDA. The two diamines were polymerized with pyromellitic dianhydride (PMDA) to prepare two isomeric polyimides (M-2,7-CPPI and 2,7-CPPI), respectively.

Impact of Backbone Amide Substitution at the Meta- and Para-Positions on the Gas Barrier Properties of Polyimide.

This study designed and synthesised a meta-amide-substituted dianiline monomer (m-DABA) as a stereoisomer of DABA, a previously investigated para-amide-substituted dianiline monomer. This new monomer was polymerised with pyromellitic dianhydride (PMDA) to prepare a polyimide film (m-DABPI) in a process similar to that employed in a previous study. The relationship between the substitution positions on the monomer and the gas barrier properties of the polyimide film was investigated via molecular simulation, wide-angle X-ray diffraction (WXRD), and positron annihilation lifetime spectroscopy (PALS) to gain deeper insights into the gas barrier mechanism.

Structure-Gas Barrier Property Relationship in a Novel Polyimide Containing Naphthalene and Amide Groups: Evaluation by Experiments and Simulations.

In order to meet the increasingly stringent requirements for heat resistance and barrier properties in the packaging and electronic device encapsulation field. A high-barrier polyimide (NAPPI) contains naphthalene ring and amide group was prepared by polymerization of a novel diamine (NAPDA) and pyromellitic dianhydride. The structure and properties of diamine monomers and polymers were characterized.

Structure and Gas Barrier Properties of Polyimide Containing a Rigid Planar Fluorene Moiety and an Amide Group: Insights from Molecular Simulations.

A novel diamine (FAPDA) bearing rigid planar fluorene and amide groups was successfully synthesized. Using such diamine and pyromellitic dianhydride (PMDA), a high-barrier polyimide (FAPPI) was obtained. FAPPI exhibits an outstanding gas barrier.

High-Barrier Polyimide Containing Carbazole Moiety: Synthesis, Gas Barrier Properties, and Molecular Simulations.

A high-barrier polyimide (2,7-CPI) was synthesized through the polymerization of pyromellitic dianhydride (PMDA) and a novel diamine (2,7-CDA) containing carbazole moiety. The synthesized diamine and polyimide were fully characterized by elemental analyses, FTIR and NMR. The 2,7-CPI displays very attractive barrier performances, with oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) low to 0.

Acylation modification of konjac glucomannan and its adsorption of Fe (Ⅲ) ion.

A biodegradable adsorbent, modified konjac glucomannan (MKGM), was prepared by konjac glucomannan (KGM) acylated with phthalic anhydride catalyzed using concentrated sulfuric acid. The modified conditions such as reaction temperature, mass ratio of phthalic anhydride to KGM, catalyst dosage and reaction time were investigated, respectively. MKGM exhibited preferable adsorption performance for the removal of Fe (Ⅲ) ion.

Molecular simulations of gas transport in hydrogenated nitrile butadiene rubber and ethylene-propylene-diene rubber.

Diffusion and sorption of five gases (H, N, O, CO, CH) in hydrogenated nitrile butadiene rubber (HNBR) and ethylene-propylene-diene rubber (EPDM) have been investigated by molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations. The diffusion coefficients of gas molecules in HNBR and EPDM are well correlated with the effective penetrant diameter except for CO. CO shows a lower diffusion coefficient due to its linear shape.

A novel study on preparation of HTiO-lithium adsorbent with titanyl sulfate as titanium source by inorganic precipitation-peptization method.

A peroxy lithium titanate sol was prepared with low-cost and easily available titanyl sulfate as the titanium source, lithium acetate as the lithium source, and aquae hydrogenii dioxidi as the complexing agent using an inorganic precipitation-peptization method. The sol system was aged, centrifugal-washed, dried and calcined to obtain a pure precursor, LiTiO, followed by pickling with hydrochloric acid to obtain the HTiO-lithium adsorbent. The effects of aging time and calcination temperature on the target product were investigated.

A meta-analysis of the relationship between NAT2 polymorphism and colorectal cancer susceptibility.

Background And Objective: Although the association between N-acetyltransferase 2 (NAT2) polymorphism and colorectal cancer (CRC) susceptibility in humans has been extensively investigated, the results are contradictory. The aim of this study was to conduct a meta-analysis of published studies to quantitatively summarize the association between NAT2 polymorphism and risk of CRC.

Material And Methods: Relevant studies that had investigated NAT2 polymorphism and CRC susceptibility were identified through a comprehensive search of Pubmed, EMBASE, Medline, Biosis, Wiley-Blackwell, ISI Web of Knowledge, CNKI, and Chinese Biomedicine Database until October 2011.