This paper contains a kind of ultraviolet-cured antifogging and antibacterial coating. A quaternary ammonium salt (14QAS), which was synthesized in this paper, has been implemented as a monomer. The chemical structure of 14QAS has been confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance. The nitrogen atom on the surface of the coatings with 14QAS was observed by X-ray photoelectron spectroscopy. The Surface wettability of the polymer film was studied by contact angle analysis, which confirmed the hydrophilicity of the coatings with low water contact angle (~25°). The antifog properties were evaluated under different conditions. The antibacterial activity of coatings with 14QAS reached 99.9% against S. aureus and E. coli. Copyright © 2014 John Wiley & Sons, Ltd.

Poly(ether sulfone) (PES) filtration membranes were chemically modified by ultraviolet-assisted graft polymerization radical reactions using two monomers, namely acrylic acid (AA) and N-vinyl-2-pyrrolidone (NVP). The reaction kinetics was assessed by applying increasing irradiation durations keeping the monomer concentration constant, and the degree of substitution of the produced materials was monitored by attenuated total reflection-Fourier transform infrared spectroscopy. The selective binding properties of the produced chemically modified membranes of a series of active pharmaceutical ingredients (APIs), namely 4-acetamidophenol (APAP), ofloxacin (OFX), ciprofloxacin (CFX), tetracycline (TC), chloramphenicol (CHPH), (±)-propranolol (PRO) and diclofenac (DF) were evaluated by means of high-performance liquid chromatography. It was observed that native PES membranes showed specific elimination of some of the selected pharmaceuticals (i.e. PRO, OFX, CFX and DF), and this elimination was improved after chemical modification with AA (except for DF). After chemical modification by NVP, the binding properties were partially improved for several pharmaceuticals, namely TC, CHPH and PRO, and partially reduced for OFX and CFX. The selective elimination of PRO was significantly improved with both AA- and NVP-modified membranes. The reported results demonstrated that the chemical modification of PES filtration membranes allowed improving significantly their API retention properties. Copyright © 2013 John Wiley & Sons, Ltd.

Mobility restrictions in solid-state photopolymerization give extremely poor polymerization kinetics, but octadecyl acrylate can be rapidly photopolymerized in the solid state. The XRD, real-time Fourier transform IR and DSC analyses prove that the hexagonal packing of monomer molecules is favorable for UV-initiated solid-state polymerization, and crystalline long alkyl chains of monomers were preserved as the crystalline long alkyl side-chains of polymers. More importantly, octadecyl acrylate provides a chance to investigate the shrinkage and oxygen inhibition of UV-induced solid-state polymerization. This novel radical-mediated solid-state photopolymerization is insensitive to oxygen and lowers the volume shrinkage (1.48%). © 2013 Society of Chemical Industry

The cationic photopolymerization of bisphenol A diglycidyl ether epoxy (DGEBA) at λ = 385 nm was conducted by the combination of a cationic photoinitiator PAG30201 (Bis (4-isobutylphenyl) iodonium hexafluorophosphate) and a photosensitizer PSS303 (9,10-dibutoxy-9,10-dihydroanthrance). The kinetic characterization was investigated by real-time Fourier transform infrared spectroscopy. The enhancement of epoxy conversion of DGEBA was achieved by increasing temperature, adding alcohols, active monomers and radical photoinitiators. As a result, in the presence of 2 wt % PAG30201 and 1.2 wt % PSS303, the epoxy rings conversion of DGEBA has reached to more than 70% from 55.9% at room temperature; it could be increased to almost 80% if heated to 60°C. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3698–3703, 2013

Novel hybrid oligomers based on a UV-curable bisphenol-S epoxy dimethacrylate (DBSMA) were synthetized. DBSMA was modified with various amount of (3-isocyanatopropyl)triethoxysilane coupling agent. The modification degree of the hybrid oligomer was varied from 0 to70 wt %. The photopolymerization kinetics was monitored by a real-time infrared spectroscopy. The conversion and rate of hybrid coatings increased with the increase in modification degree. UV-curable, hard, and transparent organic–inorganic hybrid coatings were prepared. They were performed by the analyses of various properties such as surface and mechanical properties. Results from the mechanical measurements showed that the properties of hybrid coatings improved with the increase in modification degree. The thermal behavior of coatings was also investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A dimethacrylate based on bisphenol-S (DBSMA) was prepared and characterized by Fourier Transform infrared spectroscopy (FTIR), Electrospray Ionisation Tandem Mass Spectrometry (ESI/MS) ¹H NMR, and ¹³C NMR. DBSMA was investigated by a real-time infrared spectroscopy (RTIR), under different conditions such as varying photoinitiator type and concentration, with and without oxygen, mixing with different amounts of a reactive diluent [1,6-hexanediol dimethacrylate (HDDMA)]. The mechanical and thermal properties of these curing films were also investigated by dynamic mechanical analysis and thermogravimetric analysis. The results showed homopolymer of DBSMA has better thermal stability than copolymers of DBSMA/HDDMA systems. Also, the cured DBSMA polymer exhibited higher glass transition temperature (T_g) and better thermal stability compared with commercial available resin 2,2-Bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (BIS-GMA) (CN151). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

A method based on the compression mode of a dynamic mechanical analysis was first reported to measure the real-time elastic modulus of dental composites during photopolymerization. By using this novel method, it was easy to investigate the real-time development of mechanical property of dental materials. Because the modulus development was the consequence of photopolymerization, the modulus development was governed by the double-bond conversion. High energy dose obtained by using high light intensity or long exposure time increased the “final” modulus because of the increase of conversion, but decreased the contribution of postpolymerization to the “final” modulus because of mobility limitation at high conversion. Moreover, the vitrification effect played the important role for the development of elastic modulus. The modulus significantly increased in the stage of vitrification.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

1,3-Dioxane methylcoumarin (DOMC), a novel photoinitiator (PI) for free radical polymerization, was synthesized and characterized. UV–vis absorption spectroscopy was used to investigate its photochemical behavior during the photophysical process. The photopolymerization kinetics of DOMC was studied by real-time infrared spectroscopy (FTIR). There was an optimum curing rate with the increase in DOMC concentration. Both the polymerization rate and final conversion increased with the increase in light intensity. DOMC was the most efficient PI for tripropylene glycol diacrylate (TPGDA) in different acrylate monomers. The kinetics study of TPGDA photopolymerization showed that DOMC was a more effective PI than benzophenone/ethyl-4-dimethylaminobenzoate. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Electrospun nanofibers with a core–shell structure or an internal microphase-separated structure were obtained from a homogeneous solution using a conventional single-nozzle electrospinning setup. Because of the poor miscibility of poly(ethylene oxide) (PEO) and chitosan oligosaccharide (CS), the two polymers will separate into a core–shell structure (PEO as core, CS as shell) or an internal microphase-separated structure (PEO as discrete phase, CS as continuous phase) depending on the fraction of each component in the solution. Moreover, the core–shell structure transforms to the internal microphase-separated structure with a continuous decrease of the PEO fraction. The reason for the transition of these internal structures can be attributed to the different phase separation mechanisms. For the core–shell structure, phase separation proceeds in a mechanism of nucleation and growth; however, the internal microphase-separated structure results from spinodal decomposition. Therefore, wide-angle X-ray diffraction and differential scanning calorimetry were employed to investigate PEO crystallization. Since both PEO and CS are biocompatible polymers, together with being able to control the fiber internal structure (core–shell or microphase separation), these electrospun nanofibers will have a great future in the biomedical field. Copyright © 2011 Society of Chemical Industry

In this study, glycidyl methacrylate (GMA) diethanolamine was synthesized and incorporated into polyacid main chains, which would be used for glass ionomer cements (GICs). The polymer was prepared by the free radical polymerization of acrylic acid and itaconic acid with readily synthesized GMA diethanolamine. Effects of molecular weight, polymer content in the liquid composition, powder/liquid ratio, and aging on compressive strength and diametral tensile strength were investigated. Working and setting time, water sorption and solubility (Wsl), pH value of the immersed solution, and microhardness were also measured. The experimental GICs had comparable mechanical properties to Fuji II GICs while exhibiting less Wsl and high hydrophilicity. The results suggested that the experimental GICs held promise as biocompatible and workable cement for application. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

An antisolvent processing technique by simultaneous compressed antisolvent precipitation and photopolymerization for cross-linked polymer microparticles formation was presented in this paper. In this process, photopolymerization of the homogeneous solution composed of methylene chloride, poly(ethylene glycol)600 diacrylate (PEG600DA) as monomer and diphenyl-(2,4,6-trimethylbenzoyl)-phosphine oxide (TPO) or 2,2-dimethoxy-2-phenylacetophenone (DMPA) as photoinitiator resulted to microparticle when it was sprayed into supercritical carbon dioxide (scCO₂) and simultaneously exposed to initiating light. High miscibility of the solvent in scCO₂ made methylene chloride quickly extracted from the dispersion phase, leaving very high concentrations of monomer (PEG600DA) dispersed in scCO₂. The high monomer concentration combined with photo initiating polymerization facilitates rapid reaction rates and ultimately lead to polymer precipitation. Particle size and morphology were adjustable by changing the processing conditions, such as temperature and pressure. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Oxime Ester (OXE) Photoinitiators were synthesized and characterized by HPLC, FTIR, UV–Vis spectra, and ¹H-NMR. The UV–Vis spectra of these photoinitiators were similar to Benzophenone (BP) but showed large red-shifted maximum absorption. OXE were not only soluble in many solvents and (meth) acrylate monomers but also could be dispersed easily in propylene glycol monomethyl ether acetate (PGMEA). The kinetics of polymerization of monomer using OXE as photoinitiator was studied by Real-time infrared (RTIR) spectra. It showed that OXE were an efficient photoinitiator. The concentration of OXE, functionality of monomer, and light intensity had effect on the photopolymerization kinetics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

This paper reported a polysiloxane-based photoinitiator (184-AC-Si), which was synthesized basing on traditional photoinitiator 1-hydroxy-cyclohexyl phenyl ketene (184) and polysiloxane. Its structure was confirmed by Hydrogen-1 nuclear magnetic resonance (¹H NMR), real-time infrared spectroscopy and gel permeation chromatography (GPC). Ultraviolet (UV) absorption spectra of 184-AC-Si showed a red-shifted maximum absorption compared with 184. The kinetics of photopolymerization was studied by real-time infrared spectroscopy. More importantly, because of the polysiloxane-based photoinitiator had good ability to float up, which could be proved by X-ray photoelectron spectroscopy, mapping energy dispersive spectroscopy, UV absorption, and GPC measurements, a convenient and simple method for preparing gradient polymer initiated by 184-AC-Si was successfully developed. Copyright © 2011 John Wiley & Sons, Ltd.

The real-time study of the shrinkage during UV-curing of (meth)acrylate monomers is limited due to the very fast curing rate, their thin sample geometry (<100 μm), and low viscosity. We report a reflective laser scanning system for direct measurement of UV-curing shrinkage. A low-power laser beam at a wavelength of 650 nm, different from the polymerization wavelength (395 nm), was used. This noncontact method of measurement makes it possible to analyze the thin liquid monomer with a very low shrinkage (measuring accuracy 0.02 μm), and very fast curing rate (fast sampling speed of 50 KHz). Eight different kinds of UV monomers were tested using 2–5 mg specimens, and the shrinkage process was examined. The results proved that this new method was accurate and precise, and could be applied to different kinds of (meth)acrylates. Furthermore, the shrinkage capability of acrylic double bonds was determined as 23.98 mL/mol using this novel method. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

Two low-viscosity monomers, 2-(acryloyloxy)ethyl piperidine-1-carboxylate (AEPC II) and 2-(acryloyloxy)ethyl morpholone-4-carboxylate (AEMC), were synthesized with a non-isocyanate route. The photopolymerization kinetics was monitored by real-time infrared spectroscopy with a horizontal sample holder. The results indicated that AEPC II and AEMC had high ultraviolet curing rates and final double-bond conversions, which could reach 90 and 95%, respectively. The glass-transition temperatures of AEPC II/urethane acrylate resin (1/4 w/w), AEMC/urethane acrylate resin (1/4 w/w), and isobornyl acrylate/urethane acrylate resin (1/4 w/w) mixtures were 37.5, 45.6, and 57°C, respectively. The crosslink density of the AEMC/urethane acrylate resin (1/4 w/w) mixture was lower than that of the isobornyl acrylate/urethane acrylate resin (1/4 w/w) mixture. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Near-infrared spectroscopy was used to investigate the kinetic characteristics of acrylic acid photopolymerized at −70°C and room temperature, respectively. The obtained results showed that at −70°C the double bond conversion increased with increase in the initiator's concentration. Addition of soft chain component polyethylene glycol 400 (PEG400) could lead to high conversion in the solid state, and then high final double bond conversion after post-curing. The introduction of water at low temperature also contributed largely to the enhancement in the initial and final double bond conversion in solid state. SEM photographs showed that more pores came up in the cured films with the increase in the water content in the reaction system. The change in the photoinitiator concentration, amount of PEG400, and content of water had significant effect on samples cured at lower temperature than at room temperature under the same conditions. Different kinds of photoinitiators showed different contributions to the initial and final double bond conversion on photopolymerization of acrylic acid at low temperature. Significant post-curing phenomena for photopolymerization of acrylic acid at low temperature could be observed as well. Copyright © 2009 John Wiley & Sons, Ltd.

The aim of this study was to synthesize and characterize N,N-di(methacryly-ethoxycarbonyl-ethyl)-N-(1,3-benzodioxole- 5-methylene)(DMEBM) to replace both triethylene glycol dimethylacrylate(TEGDMA) as a dilute and the non-polymerizable amine, which is added as a co-initiator in dental resin mixtures. 2,2-bis[4-(2-Hydroxy-3-methacryloxypropoxy) phenyl]-propane (Bis-GMA) and camphorquinone (CQ) were used as monomer and photoinitiator in these model dental resin systems, in contrast to ethyl 4-dimethylaminobenzoate (EDMAB) which was usually used as a co-initiator. DMEBM was synthesized via Michael-Addition reaction and characterized using ¹H NMR spectroscopy. A mixture of Bis-GMA/DMEBM/CQ was found to reach the double bond conversion of 67.5%, slightly higher than that of Bis-GMA/TEGDMA/CQ/EDMAB (66.8%) and Bis-GMA/TEGDMA/CQ/DMEBM (64.8%). In addition, the glass transition temperature of Bis-GMA/TEGDMA/CQ/EDMAB (93.4°C) were higher than that of Bis-GMA/TEGDMA/CQ/DMEBM (89.3 °C) and Bis-GMA/DMEBM/CQ (80.4°C). The water sorption and solubility of Bis-GMA/TEGDMA/CQ/DMEBM were higher than that of Bis-GMA/TEGDMA/CQ/EDMAB and Bis-GMA/DMEBM/CQ. However, the values were still within the range of the ISO 4049 standards. DMEBM could be used as a potential co-initiator and diluent for dental composite. Copyright © 2009 John Wiley & Sons, Ltd.

Electrospinning provides a simple and versatile method for fabricating nanofiber mats. Electrospun fiber mat of well aligned and order architectures was often required for many applications. In this communication, biaxial orientation mats were electrospun by a novel collector consisting of two rotating disks with conductive edge. In addition, an auxiliary electrode was induced to focus the electrostatic field and force the fibers to align regularly. The biaxial orientation structure was formed with the variation of rotation speed without revolving the fiber mat during the electrospinning process, and the dates presented in this paper demonstrated that the degree of biaxial orientation strongly depended on the rotation speed. This simple method has potential applications in textile and electronic areas. Copyright © 2009 John Wiley & Sons, Ltd.

Cyclic acetals were proposed as free radical polymerization photoinitiators or co-initiators. The photopolymerization kinetics was recorded by real-time infrared spectroscopy (RTIR). 2-proply-1,3-benzodioxole (PBDO) and 2-hexyl-1,3-benzodioxole (HBDO) were efficient photoinitiators for the polymerization of 1,6-hexanedioldiacrylate (HDDA). Polymerization occurred at the highest rate with 1,3-benzodioxolane (BDO) as a co-initiator. When 1.82 wt % benzophenone (BP) was used as a photoinitiator, the addition of PBDO increased the rate of polymerization (R_p) and the final double bond conversion (DC_f) of HDDA, and an optimum cure rate (0.982 min⁻¹) was obtained at 1.64 wt % of PBDO. Combination of p-chlorobenzophenone (CBP) and PBDO had the highest initiating reactivity. Cyclic acetals were inefficient co-initiators for isopropylthioxanthone (ITX). Copyright © 2009 John Wiley & Sons, Ltd.

The blend film was prepared by casting solutions of water-soluble hydroxyethyacryl-chitosan (HEA-CS) and polyvinyl alcohol (PVA) and cross-linked by glutaraldehyde. The structure and properties of the blend films were estimated by wide-angle X-ray diffraction (WXRD), contact angle measurements with water, and scanning electron microscopy (SEM). The tensile properties of the blend films were investigated and the tensile strength (TS) and the elongation increased with the increased amount of PVA. The thermal stability (thermogravimetric (TG) and derivative thermogravimetric (DTG)) was evaluated and HEA-CS was more thermally-stable than that of PVA. The water swelling properties analysis indicated that HEA-CS in the blends promoted the water absorption owing to its porous structure and the antimicrobial ability of the blend films was retained. Indirect cytotoxicity assessment of the blend films with human bone sarcoma cell (SW1353) indicated that the biomaterials were non-toxic and did not release substances harmful to living cells. Copyright © 2009 John Wiley & Sons, Ltd.

The ultrafine composite fibers had been successfully achieved by electrospinning of chloroform solutions of octadecyl chitosan (O-CS) and poly(ethylene oxide) (PEO). The ultrafine composite fibers membranes were subjected to detailed analysis by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and water contact angle (WCA). The FTIR results confirmed that ultrafine composite fibers contained the two polymers. The SEM images showed that the morphology and diameter of the composite fibers were mainly affected by the weight ratio of O-CS/PEO, the electric field strength, and the collection distance. The WCA data demonstrated that the composite fibers membranes performed a quite hydrophobic character. The special morphology of neck and porous structure was observed experimentally during electrospinning. The neck structure was due to the fibers elongated in the direction of stretching through the electric field, and the porous structure was decided by the competition between the phase separation and the fast evaporation rate of chloroform. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Polymeric micelles that are responsive to pH are particularly attractive for application in drug delivery systems. In this study, one type of amphiphilic block copolymers with hydrophobic building blocks bearing pH-sensitive ketal groups was designed. In an acidic environment, the polarity transfer from amphiphile to double hydrophile for this copolymer destroyed the driving force of micelle formation, which triggered the release of encapsulated hydrophobic molecules. The amphiphilic block copolymers monomethoxy-poly(ethylene glycol)-block-poly(2,2-dimethyl-1,3-dioxolane-4-yl)methyl acrylate (MPEG-block-PDMDMA) was fabricated by atom transfer radical polymerization using MPEG-Br as macroinitiator. The critical micelle concentration of various compositions of this copolymer in aqueous solution ranged from 4.0 to 10.0 mg L⁻¹, and the partition equilibrium constant (K_v) of pyrene in micellar solutions of the copolymers varied from 1.61 × 10⁵ to 4.86 × 10⁵. Their overall effective hydrodynamic diameters from dynamic light scattering measurements were between 80 and 400 nm, and the micellar morphology showed spherical geometry as investigated using transmission electron microscopy. At pH = 1.0, all of these polymeric micelles presented 100% payload release in 24 h of incubation, while at pH = 3.0, nearly 70 and 25% of pyrene was released for MPEG-block-PDMDMA (44/18) and MPEG-block-PDMDMA (44/25) in 260 h, respectively. The pH-responsive MPEG-block-PDMDMA polymeric micelles having good encapsulation efficiency for hydrophobic drugs are potential candidates for biomedical and drug delivery applications. Copyright © 2010 Society of Chemical Industry

In the present contribution, the ultrafine fiber membranes of polyhydroxybutyrate (PHB) and organic-soluble chitosan(O-CS) was prepared by electrospinning. The structure and thermal stability were studied by infrared (FTIR) and thermogravimetric analysis (TG). The surface properties of ultrafine fibers were estimated by contact angle measurements using water. The morphology was observed by scanning electron microscopy (SEM). The cytotoxicity assessment with mouse fibroblast cells (L929) was also investigated. Cell culture results showed that it benefits promoting the cell attachment and proliferation. The results showed it could be as tissue engineering for skin regeneration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Polymerizable ammonium surfactants with two methacrylate alkyl chains were successfully synthesized via Michael-Addition and quaternization reaction. Organoclays containing reactive methacrylate groups were prepared by cationic exchange process. Intercalated nanocomposites have been produced by UV initiated polymerization with different organophilic clay loading. X-ray diffraction (XRD) spectroscopy showed that the d spacing of organoclay increased with increment of methacrylate alkyl chains length. When organoclay were dispersed in urethane acrylate resin, and photopolymerized, the d spacing increased, but the increasing extent decreased with increment of the methacrylate alky chains length. Thermogravimetric analysis indicated that incorporation of reactive organoclay had better thermal stablity than cetyltrimethylammonium bromide (CTMA)-modified organoclay and dynamic mechanical analysis (DMA) showed nanocomposites containing reactive organoclay had high glass transition temperature and storage modulus. Tensile analysis implied that incorporation of reactive organoclay could enhance mechanical and tensile properties dramatically. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

A water soluble methylated β-cyclodextrin/camphorquinone (MCD/CQ) complex, based on methylated β-cyclodextrin (MCD) and camphorquinone (CQ), was prepared and its structure was characterized by FTIR, ¹H-NMR, and UV–vis spectra. The photopolymerization kinetics of MCD/CQ in the water soluble monomer system was studied by Real-time Infrared spectroscopy (RT-IR). Compared to the photopolymerization carried out under nearly identical conditions but without MCD, the polymerization rate and final conversion initiated by a CQ-triethanolamine photoinitiator system were slightly lower. The effects of different MCD/CQ concentration, triethanolamine concentration, and light intensity were also studied. Copyright © 2009 John Wiley & Sons, Ltd.

Alicyclic hydroxy methacrylate monomer, o-hydroxycyclohexyl methacrylate (HCMA), was synthesized and characterized by Fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (¹H-NMR). Photopolymerization kinetics of HCMA was investigated via real-time infrared spectroscopy (RT-IR). Polymeric network hydrogels based on hydroxyethyl methacrylate (HEMA) and HCMA were prepared by using the photopolymerization technique. Mechanical strength, swelling characteristic, and controlled release behavior of hydrogels with various feed compositions were studied. Poly(HEMA-co-HCMA) hydrogel had higher storage modulus than that of poly(HEMA) hydrogel as investigated by dynamic mechanical analysis (DMA). Acid orange 8 was used as a model drug for the investigation of drug release behavior of copolymeric hydrogels. Results indicated that increase in HCMA ratio in hydrogel composition could reduce the swelling rate and prolong the release time. Scanning electron microscopy (SEM) was also utilized to study the surface morphology of hydrogels, and the results indicated that HCMA content influenced pore diameter on the hydrogel surface. Copyright © 2008 John Wiley & Sons, Ltd.

A facile method for the preparation of porous ultrafine nanofibers was demonstrated. The PAN/NaHCO₃ composite nanofibers were electrospun, and then NaHCO₃ was removed by a selective dissolution and reaction with the solution of hydrochloric acid (10 wt%). The obtained PAN fibers showed highly porous surfaces after the extraction of NaHCO₃. The structure and properties of ultrafine PAN nanofibers were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and thermogravimetry (TG). The results indicated that NaHCO₃ could be introduced into the PAN solution and successfully electrospun. CO₂ is released and pores are formed on the fibers. The morphology image of the fibers was detected by scanning electron microscope (SEM) and showed that many pores aligned the nanofibers. Copyright © 2008 John Wiley & Sons, Ltd.

Two multifunctional aromatic urethane acrylates, based on 2, 4-toluene diisocyanate (2, 4-TDI), β-hydroxyethyl arcylate (HEA), and synthetic multifunctional hydroxyl compounds, were synthesized by classical condensation reaction. FTIR was used to monitor the process of the reaction. The photopolymerization kinetics of the urethane acrylates with different photoinitiators was studied by Real-Time Infrared Spectroscopy. The results indicated that different from the commercial urethane acrylate CN 975, the synthetic multifunctional urethane acrylates could be efficiently initiated by BP without the addition of any co-initiators as they have tertiary amine structures. Copyright © 2008 John Wiley & Sons, Ltd.

Two multifunctional aliphatic urethane acrylates, based on isophorone diisocyanate (IPDI), β-hydroxyethyl arcylate (HEA), and synthetic multifunctional hydroxyl compounds, were synthesized by classical condensation reaction. FTIR was used to monitor the process of the reaction. The photopolymerization kinetics of the urethane acrylates with different photoinitiators was studied by real-time infrared spectroscopy. The results indicated that compared with the commercial hexa-functional urethane acrylate CN 9010, the synthetic multifunctional urethane acrylates could be initiated by benzophenone more efficiently without the addition of any coinitiators because they have tertiary amine structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

UV-curable nanocomposites were prepared by the in situ photopolymerizaton with nanosilica obtained from sol–gel process. The photoinitiator 2-hydroxy-2-methyl-1-phenylpropane-1-one (1173) was anchored onto the surface of the nanosilica with or without methacryloxypropyltrimethoxysilane (MAPS) modification. The photopolymerization kinetics was studied by real-time Fourier transform IR (RTIR), and the microstructure and properties of the nanocomposite were investigated using transmission electron microscopy and UV–visible (UV–vis) transmistance spectra. RTIR analysis indicated that the nanocomposites without MAPS had higher curing rates and final conversion than those with MAPS. The nanocomposites with an uniformal dispersion of nanosilica had high UV–vis transmittance. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The size of “bowl-like” structures woven by nanofibers could be controlled by adjusting the distance from the nozzle to a modified collector and the voltage applied to the electrospinning device. More interestingly, the nanofibers in the side wall of the “bowl” could vibrate up and down with the changing of the voltage. This voltage-induced vibration might have potential applications for bio-mimic process and micro-motor devices. Copyright © 2008 John Wiley & Sons, Ltd.

A copolymerizable one-component Type II photoinitiator (CMEBP), based on 4-hydroxybenzophenone (HBP), epichlorohydrin, morpholine, and acryloyl chloride, was synthesized and its structure was confirmed by ¹H-NMR. The properties of CMEBP were investigated with UV spectroscopy and photo-differential scanning calorimetry (photo-DSC). The maximum of UV absorption red-shifted significantly compared to benzophenone (BP). Photopolymerization results of tripropylene glycol diacrylate (TPGDA) indicated that CMEBP had larger maximum rate of polymerization than that of BP/triethanolamine (TEOHA) and HBP/triethylamine (TEA), larger final double bond conversion than that of HBP/TEA, but lower than that of BP/TEOHA. The rate of polymerization, final conversion increased and the induction period shortened with increase in CMEBP concentration. Copyright © 2008 John Wiley & Sons, Ltd.

Biocompatible pH-sensitive semi-interpenetration polymeric network hydrogels (semi-IPN) based on water-soluble N-carboxyethyl chitosan (CECS) and 2-hydroxyethyl methacrylate (HEMA) were synthesized by the photopolymerization technique. pH-sensitivity, cytotoxicity, morphology, mechanical property, and water state of hydrogel were investigated by a swelling test, methylthiazolydiphenyl-tetrazolium bromide (MTT) assay, scanning electron microscopy (SEM), universal testing machine, and differential scanning calorimetry (DSC), respectively. The drug release studies were carried out using 5-Flurouracil as the model drug. The results indicated that the hydrogels were sensitive to pH of the medium and its wet state had good mechanical properties. The results of cytotoxicity and prolonged drug release characteristics revealed the suitability of the hydrogels as drug delivery matrices. The release kinetics was evaluated by fitting the experimental data to standard release equations, and the best fit was obtained with the Higuchi model of the hydrogel. Copyright © 2008 John Wiley & Sons, Ltd.

A one-component type II photoinitiator (PDBP), based on 4-hydroxybenzophenone (HBP), acryloyl chloride, and piperazine, was synthesized and its structure was confirmed by ¹H-NMR. The photopolymerization kinetics of the photoinitiator was studied by real-time Infrared spectroscopy (FT-IR). It indicated that PDBP was a more effective photoinitiator than that of BP/triethylamine (TEA). The rate of polymerization, final conversion increased and the induction period shortened with increase in PDBP concentration, light intensity, and amine concentration. The kinetics of photopolymerization for TPGDA incorporating PDBP in the presence of different tertiary amines as the initiating system indicated that the PDBP/TEA combination exhibited the highest polymerization rates among the PDBP/amine combinations. Copyright © 2007 John Wiley & Sons, Ltd.

Nanofibrous biocomposite scaffolds of chitosan (CS), PVA, and hydroxyapatite (HA) were prepared by electrospinning. The scaffolds were characterized by FTIR, SEM, TEM, and XRD techniques. Tensile testing was used for the characterization of mechanical properties. Mouse fibroblasts (L929) attachment and proliferation on the nanofibrous scaffold were investigated by MTT assay and SEM observation. FTIR, TEM, and XRD results showed the presence of nanoHA in the scaffolds. The scaffolds have porous nanofibrous morphology with random fibers in the range of 100–700 nm diameters. The CS/PVA (90/10) fibrous matrix (without HA) showed a tensile strength of 3.1 ± 0.2 MPa and a tensile modulus 10 ± 1 MPa with a strain at failure of 21.1 ± 0.6%. Increase the content of HA up to 2% increased the ultimate tensile strength and tensile modulus, but further increase HA up to 5–10% caused the decrease of tensile strength and tensile modulus. The attachment and growth of mouse fibroblast was on the surface of nanofibrous structure, and cells' morphology characteristics and viability were unaffected. A combination of nanofibrous CS/PVA and HA that mimics the nanoscale features of the extra cellular matrix could be promising for application as scaffolds for tissue regeneration, especially in low or nonload bearing areas. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Electrospinning has been extensively explored as a simple and versatile method for drawing fibers. The nanofibers are usually collected as nonwoven mats. The results presented in this article show that the electrospun nanofibers can be uniaxially aligned by introducing two nonconductive ferrite magnets collector, and polymer chains parallel to the fiber axis for the aligned nanofibers. The alignment of the nanofibers was characterized by use of digital cameras and field emission scanning electron microscopy. Alignment on the molecular level was investigated by polarized Fourier transform infrared spectroscopy, polarized Raman spectroscopy, and wide-angle X-ray diffraction. Such uniaxially oriented nanofibers exhibit a variety of potential applications in the areas of biomaterials, microelectronics, and photonics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

The electrospun fibers chitosan/polyvinyl alcohol (CS/PVA) were crosslinked by the incorporation of photocrosslinking agent poly(ethyleneglycol)-600-dimethacrylate (PEGDMA) and photoinitiator 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (HEPK) into the spinning solutions and a subsequent irradiation by UV light. The photocrosslinking process of CS-based nanofibers was studied by the Fourier transform infrared spectra, and the water resistance was investigated by scanning electron microscopy (SEM) and water swelling measurement. The results indicated that the water resistance of photocrosslinked CS-based nanofibers was improved obviously and the swelling ratio decreased with the increasing content of PEGDMA/HEPK. When the concentration of crosslinking agent was 20 wt %, the swelling ratio value decreased to half of that in none crosslinking CS/PVA nanofiber membranes, further increasing the concentration of crosslinking agent to 50 wt %, the swelling ratio value was one eighth of the none crosslinking CS/PVA nanofiber membranes. Cytotoxicity evaluation by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay indicated that the photocrosslinked CS-based fiber membranes were nontoxic to L929 cells. Results from cell culture SEM imaging showed that cells which exhibited the spindle shape could grow properly on the surface of nanofibrous structure of the CS/PVA. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

N-alkylated chitosan derivatives were synthesized in water containing acetic acid by the Michael addition reaction of chitosan with various acryl reagents. The chemical structures of the chitosan derivatives were characterized with Fourier transform infrared and ¹H-NMR techniques. The ¹H-NMR results indicated that the degree of substitution of the chitosan derivatives ranged from 0.13 to 0.39. The chitosan derivatives exhibited different solubilities in distilled water. X-ray diffraction analysis showed that the chitosan derivatives were amorphous. The chitosan derivatives still had antimicrobial ability. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

A novel difunctional photoinitiator HBP-TDI-HBP based on 4-hydroxybenzophenone (HBP) and toluene-2,4-diisocyanate (TDI) was synthesized and characterized by ¹H NMR and UV–Vis absorption spectroscopy. The kinetics of photopolymerization was studied by real-time infrared spectroscopy. It showed that HBP-TDI-HBP was a more effective photoinitiator than benzophenone. When this photointiator and amine were used to efficiently initiate polymerization of acrylates and methacrylates, both rate of polymerization and final conversion increased with increase of HBP-TDI-HBP concentration, light intensity, and amine concentration. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

BACKGROUND: Electrospinning is a versatile method to process solutions or melts into micro- or nanofibers. Several mathematic models for electrospinning have been established, focused mostly on the fiber formation process, but seldom on the distribution of collected fibers by considering the electric field effect.

RESULTS: A method based on electric potential and coulombic interactions was developed to simulate the distribution of electrospun fibers. Two different types of electric field were investigated; and the process was interpreted by schematic diagrams and physical equations. In this case, the simulation analysis based on idealized models is convenient to understand the effect of the distorted electric field induced by different types of collectors.

CONCLUSION: The effects of electric potential and Coulombic interactions are the decisive factors in the collect process. The mathematic model can indeed predict the distribution of electrospun fibers. Copyright © 2008 Society of Chemical Industry

A polymeric one-component type II photoinitiator (PDABPP) based on 4,4′-dihydroxybenzophenone (DHBP), acryloyl chloride, and piperazine was synthesized, and its structure was confirmed by GPC and ¹H NMR. The photopolymerization kinetics of the photoinitiator was studied by real-time infrared spectroscopy. It indicated that PDABPP was a more effective photoinitiator than that of benzophenone (BP)/triethylamine (TEA). The rate of polymerization and final conversion increased, and the induction period shortened with increase of PDABPP concentration, light intensity, and amine concentration. The kinetics of photopolymerization for tripropylene glycol diacrylate (TPGDA) incorporating PDABPP in the presence of different tertiary amines as the initiating system indicated that the PDABPP/TEA combination exhibited the highest polymerization rates among the PDABPP/amines combinations. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers