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pH-Sensitive Hydrogels Based on (Meth)Acrylates and Itaconic Acid
Simonida Lj. Tomić,Marija M. Babić,Katarina M. Antić,Jovana S. Jovašević Vuković,Neda B. Malešić,Jovanka M. Filipović 한국고분자학회 2014 Macromolecular Research Vol.22 No.11
Novel hydrogels based on 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and different poly(alkylene glycol) (meth)acrylates (PAGM) (P(HEMA/IA/PAGM)) were synthesized. We investigated the influenceof different PAGM components, with acrylic or methacrylic acid residues in the main chain and ethylene glycol (EG)and/or propylene glycol (PG) units in pendant chains of varying length, on the nature and inherent properties ofP(HEMA/IA/PAGM) copolymeric hydrogels. Swelling studies revealed pH sensitive behavior of P(HEMA/IA/PAGM)samples. Hydrogel structure and morphology were characterized by Fourier transform infrared (FTIR) spectroscopyand scanning electron microscopy (SEM), which confirmed their chemical structure and differences in pore size. The shear modulus values for P(HEMA/IA/PAGM) hydrogels were close to that of PHEMA, but slightly lower thanthe value for P(HEMA/IA). Cephalexin (CEX) drug release profiles from P(HEMA/IA/PAGM) samples showed amarked dependence on the PAGM component. The presence of IA also influenced the release rate of CEX, leadingto a faster release when IA was combined with the more hydrophilic PAGM component. An in vitro assay of P(HEMA/IA/PAGM) cytotoxicity showed good cell viability. The results obtained indicate that P(HEMA/IA/PAGM) hydrogelproperties were significantly dependent on the PAGM component, meaning that the type of side chains can be usedto tune the characteristics of such biomaterials. These properties make P(HEMA/IA/PAGM) copolymeric hydrogelsapplicable in biomedical and biotechnological fields and controlled drug delivery.
Male, U.,Jo, E.J.,Park, J.Y.,Huh, D.S. IPC Science and Technology Press 2016 Polymer Vol.99 No.-
We present a new and facile strategy for the fabrication of conducting honeycomb-patterned porous films through interfacial polymerization. Polymer solutions containing poly(ε-carprolactone) (PCL) and benzoyl peroxide (BPO) in chloroform was fabricated under high humid conditions to obtain PCL-BPO honeycomb patterned films. The films were treated with aqueous aniline hydrochloride solution to polymerize aniline at the interface of the PCL film and aniline hydrochloride solution. PCL-BPO films served dual role of a template as well as an oxidant. The proposed strategy retains the electrical conductivity of polyaniline as well as the mechanical strength and biodegradable properties of PCL. In contrast with in-situ templated bulk polymerization methods, the proposed method exhibits the advantage of retaining porosity without causing any wreckage.
Malee JATURAT,Kusuma DAMPITAKSE,Chanongkorn KUNTONBUTR 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.12
The objective of this research is to investigate how the board of directors’ characteristics influence sustainability disclosures with the mediating effect of corporate governance. The independent variables are the characteristics of the board of directors, which consist of the presence of women on the boards, presence of directors aged over 50 years old, education level, education field, board tenure, and compensation. The dependent variable is sustainability disclosures, which is measured by the GRI standard disclosure, whereas the mediator variable is the CG score. Research samples are 460 companies listed on the Stock Exchange of Thailand (SET). Path Analysis is used to examine the correlation between the board of directors’ characteristics, CG score, and GRI standard disclosure. The research findings show that senior boards, the education field, and compensation motivation have an effect on sustainability disclosures, whereas corporate governance is a mediator of the effect of the education field of boards on sustainability disclosures. This finding should help shareholders to choose individuals with suitable characteristics to serve on the board of directors, and, as a result, shareholders should anticipate a profitable result to be generated, while the business of the company is conducted in a sustainable way.
Male, Umashankar,Shin, Bo Kyoung,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.
<P><B>Abstract</B></P> <P>A new and facile method was designed for the fabrication of asymmetrically polyaniline (PANI) functionalized polystyrene (PS) honeycomb-patterned porous films in a single step. The method involves the coupling of breath figure process with an interfacial polymerization, wherein the PS solution containing benzoyl peroxide in an organic solvent was cast under humid conditions over an aqueous solvent containing aniline and methane sulfonic acid. PANI was coated on the bottom surface at the organic/aqueous interface by an interfacial polymerization method, whereas a porous patterned PS was fabricated on the top surface by the breath figure method. The films revealed a translucent insulating PS top surface and a conducting green PANI bottom surface. The obtained films represented asymmetrical composition, color, morphology, conductivity, and contact angle on either surface.</P> <P><B>Highlights</B></P> <P> <UL> <LI> First report on asymmetric functionalized honeycomb patterned films. </LI> <LI> Film was obtained by coupling interfacial polymerization with breath figure process. </LI> <LI> It has asymmetrical color, composition, morphology, contact angle and conductivity. </LI> <LI> These can be used in applications where asymmetrical property is a requirement. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Polyaniline decorated honeycomb-patterned pores: Use of a reactive vapor in breath figure method
Male, Umashankar,Shin, Bo Kyoung,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.
<P><B>Abstract</B></P> <P>A new strategy is proposed to obtain pore functionalized honeycomb-patterned porous films by in-situ polymerization during breath figure process. The polystyrene with benzoyl peroxide mixture in chloroform was casted under reactive vapor conditions, generated by pumping air through aqueous aniline hydrochloride solution. The resulting films showed honeycomb patterned porous morphology with polyaniline functionalized pores. The formation of polyaniline was confirmed from color, conductivity, and UV-Visible studies. The strategy can be extended to obtain various pore functionalized films by choosing one reactant in polymer solution and other in humid vapors.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pore functionalized ordered porous films by reactive vapor in breath figure method. </LI> <LI> It was possible by coupling interfacial polymerization with breath figure method. </LI> <LI> Functionalization achieved at condensed reactive droplet/polymer solution interface. </LI> <LI> The strategy can be applied to obtain a wide variety of pore functionalized films. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Male, Umashankar,Modigunta, Jeevan Kumar Reddy,Huh, Do Sung Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.
<P><B>Abstract</B></P> <P>To increase the pseudo-capacitance and cycle stability of polyaniline (PANI), PANI was covalently attached to reduced graphene oxide (rGO) via azobenzene (Azo) units. The rGO-Azo composite was first synthesized and subsequently used for the in situ chemical polymerization of aniline to form PANI-rGO-Azo composites. The Azo units on rGO functioned as spacers to prevent the agglomeration of rGO and increase the solubility of rGO to assist in the in situ polymerization of aniline to form PANI-rGO-Azo composite. The Azo units act as linkers for the covalent attachment of PANI chains to graphene, thereby enhance the overall performance of the composite materials. The electrochemical properties of the composites were evaluated by fabricating symmetric two-electrode cell configuration and also compared with three electrode system. The charge transfer resistance of PANI is reduced from 6.6 Ω to 2.9 Ω, by grafting PANI onto rGO-Azo. The specific capacitance of PANI-rGO-Azo (328 F g<SUP>-1</SUP>) is higher than that of PANI (270 F g<SUP>-1</SUP>) and rGO-Azo (114 F g<SUP>-1</SUP>). The electrochemical performance of PANI was enhanced by grafting of PANI onto rGO-Azo.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Charger transfer resistance of PANI is reduced by grafting onto rGO-Azo. </LI> <LI> Knee frequency of PANI-rGO-Azo was higher than PANI. </LI> <LI> 80% of initial capacitance was retained even after 1500 charge-discharge cycles. </LI> <LI> PANI-rGO-Azo shows higher electrochemical performances than PANI. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>