bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of isotropic compatible HDPE/PP blends for structural applications
Authors: Zahran Rouchdy R. , Abd El‐Latif Mona Mahmoud , Konsowa Abd El‐Aziz H. , Awwad Marwa
Published: October 2009

In an attempt to provide superior products for the structural applications, this study aimed at preparing isotropic compatible high density polyethylene (HDPE)/ polypropylene (PP) blends without the use of the expensive compatibilization technique. Morphological and structural characterizations of the homopolymers and blends were carried out. In addition, some of the structurally important mechanical and thermal properties were characterized. Such characterizations were performed to investigate whether or not the blends are compatible and therefore acceptable for the structural applications. Scanning electron microscope (SEM) micrographs of the blend samples indicate that the interfacial adhesion between HDPE and PP phases is intimate in the 5/95 HDPE‐PP, good in the 85/15 HDPE‐PP and 95/5 HDPE‐PP, fair in the 30/70 HDPE‐PP and very poor in the 50/50 HDPE‐PP. Similarly, mechanical and thermal responses of the first three blends are remarkable. The 30/70 HDPE‐PP blend displays a fairly good performance. Whereas, the properties of the 50/50 HDPE‐PP blend are very poor. This decides that the first three blends are compatible and, therefore, structurally attractive materials. The fourth is partially compatible and, as a consequence, can be rather acceptable for the structural applications. However, the fifth is incompatible and, of course, is not acceptable for such applications. On the other hand, SEM micrographs and differential scanning calorimetry results indicate that the crystalline structures of individual polymers are appreciably affected by blending. Additionally, the study reveals that the end use performance of blends is strongly dependent on the crystalline structure changes occurring in each component due to blending as well as the compatibility between the blend components. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic and thermomechanical analysis of hydrophobic–hydrophilic copolymer thermosets synthesized via free‐radical polymerization
Authors: Rahmathullah M. Aflal M. , Elabd Yossef A. , Palmese Giuseppe R.
Published: October 2009

The synthesis of a crosslinked copolymer of hydrophobic and hydrophilic monomers, diglycidyl ether of bisphenol A vinyl ester (VE), and 2‐acrylamido 2‐methyl 1‐propane sulfonic acid (AMPS) respectively, is discussed. A methodology for real‐time monitoring of the copolymerization reaction using transmission mode near infrared (NIR) spectroscopy was employed that resolves overlapping peaks associated with the reactive double bonds. The influence of solvent, monomer ratio, and initiator concentration on the kinetic behavior of the system was investigated. The method of Mayo and Lewis was used to provide a qualitative understanding of the microstructure being formed. At low conversions (<15%) and within the compositions of interest, greater VE homopolymerization as compared with AMPS homopolymerization was observed and the product of the reactivity ratios (rAMPS.rVE) was close to 0.5, suggesting the formation of a moderately random copolymer structure. Thermo‐mechanical analysis shows large concentrations of AMPS had a plasticizing effect on the network structure. Solvent removal using supercritical carbon dioxide and thermal drying were compared, and the drying technique were shown to have an effect on the glass transition temperature (Tg), with the lowest Tg being 146°C for supercritically dried samples and 121°C for thermally dried systems. Gel permeation chromatography shows that there is a significant fraction of an unbound mobile phase within the network structure that might be acting as a plasticizing agent for the copolymer structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Development and characterization of cellulose‐based hydrogels for use as dietary bulking agents
Authors: Sannino Alessandro , Madaghiele Marta , Demitri Christian , Scalera Francesca , Esposito Annaclaudia , Esposito Vincenzo , Maffezzoli Alfonso
Published: October 2009

In the last decade, cellulose‐based hydrogels have been receiving increasing attention for a number of applications because of their smart swelling behavior, biodegradability, and biocompatibility. Given the dramatic spreading of obesity and overweight in the industrialized countries and the lack of scientific consensus over currently available dietary supplements, it was recently proposed that such hydrogels might be used as orally administered bulking agents in hypocaloric diets, because the hydrogel swelling in the stomach may greatly reduce the space available for food intake, thus giving a sense of fullness. This study is focused on the synthesis of cellulose‐based hydrogels, starting from pharmaceutical and food grade cellulose derivatives, and shows that such hydrogels possess good swelling properties in water solutions mimicking the environmental conditions of the stomach and the intestine, as well as a good biocompatibility. The crosslinking agent used was a “zero‐length” crosslinker, that is, a water soluble carbodiimide, which is washed out from the gel after the synthesis and does not affect the gel compatibility, as shown by preliminary biocompatibility assays. The experimental results confirmed that cellulose‐based hydrogels might be a scientifically valid dietary adjuvant in the treatment of obesity and overweight, and provide further scientific evidence for future experiments on humans. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Diffusion and sorption studies of dyes through PVA cryogel membranes
Authors: Papancea Adina , Valente Artur J. M. , Patachia Silvia
Published: October 2009

The capacity of poly(vinyl alcohol) (PVA) to crosslink through freeze/thaw method was used to obtain PVA hydrogel membranes (HG) that were subjected to sorption and diffusion experiments using three dyes: Congo red (CR), methylthymol blue (MTB), and crystal violet (CV). To study the sorption of dyes into the cryogenic membrane, dye solutions at different concentrations were used. After sorption, desorption of dyes from the PVA membrane was monitored to quantify the possible regeneration of the membrane (PVA HG). To have a deep insight on the mechanism behind the desorption process, dye‐release kinetics were studied. The diffusion experiments reveal the fact that CR and MTB do not permeate the PVA HG membrane making it a promising candidate in the advanced purification processes of wastewaters. The effect of the incorporation of dyes (CV, CR, and MTB) on the chemical properties of PVA cryogel matrices has been studied by using several techniques such as: differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Conjugated copolymers of cyanosubstituted poly(p‐phenylene vinylene) with phenylene ethynylene and thienylene vinylene moieties: Synthesis, optical, and electrochemical properties
Authors: Zou Yingping , Peng Bo , Liu Bo , Li Yongfang , He Yuehui , Zhou Kechao , Pan Chunyue
Published: October 2009

Three alternating conjugated copolymers of cyanosubstituted poly(p‐phenylene vinylene) (CN–PPV) with phenylene ethynylene and thienylene vinylene moieties, P1, P2, and P3, were synthesized via cross‐coupling polycondensation with Pd(PPh3)2Cl2 as a catalyst. Their structures were confirmed by 1H‐NMR, IR spectroscopy, elemental analysis, and gel permeation chromatography, and the thermal, photophysical, and electrochemical properties of the copolymers were also investigated. The incorporation of a triple bond into the CN–PPV backbone led to higher reduction potentials, which corresponded to lower lowest unoccupied molecular orbital energy levels. The three copolymers possessed broader absorption spectra, especially copolymer P3 with its polymerization units containing two thiophene rings, which showed the broadest absorption spectrum, from 300 to 710 nm. Their high electron affinities, broad absorptions, and relatively higher oxidation potentials make the copolymers potentially good electron‐acceptor material for use in photovoltaic devices. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of injectable paclitaxel sustained release microspheres by spray drying for inhibition of glioma in vitro
Authors: Song Tian‐Tian , Yuan Xu‐Bo , Sun Ai‐Ping , Wang Hong , Kang Chun‐Sheng , Ren Yu , He Bin , Sheng Jing , Pu Pei‐Yu
Published: October 2009

The major aim of this work was to prepare injectable paclitaxel‐loaded poly(D,L‐lactide) microspheres for the inhibition of brain glioma. Paclitaxel‐loaded PLA microspheres were prepared by spray drying method employing ethyl acetate as solvent. And the microspheres were characterized by scanning electron microscopy (SEM) for the morphology and differential scanning calorimetry for thermal analysis. The encapsulation efficiency (EE) and in vitro release profiles of paclitaxel‐loaded microspheres were determined by using ultraviolet spectrophotometer. The results showed that the microspheres possess a narrow size distribution with the average diameter of 4.6 μm. The surface of the microspheres was smooth, and the paclitaxel dispersed in microspheres in amorphous state. The solvent residue was 0.03%, and the EE reaches ∼ 90%. The microspheres exhibited a sustained release behavior, and the release period last for at least three months, depending on the EE of the microspheres. The γ irradiation sterilization had little effect on the EE and drug release in vitro. Compared with the commercial formulation, the sustained release microsphere showed a stronger inhibition on the tumor cells, suggesting the potential application of long‐term delivery of paclitaxel‐loaded PLA microspheres in clinic tumor therapy. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on properties and aggregation structures of deacetylated konjac glucomannan/chitosan hydrochloride absorbent blend gel films
Authors: Liu J. , Li B. , Zhu B. , Fu R.H. , Yuan L.N. , Huang W. , Ma M.H.
Published: October 2009

A series of novel blend films of deacetylated konjac glucomannan (d‐KGM) and Chitosan hydrochloride (CHI·HCl) were prepared successfully by using the solvent‐casting technique with different blending ratios of the two polymers. The miscibility and aggregation structure of the blend films were studied by Fourier transform infrared spectroscopy, wide‐angle X‐ray diffraction and scanning electron microscopy. The results indicated that the blend system of d‐KGM and CHI·HCl had a conditional miscibility. A new crystal occurred and hydrogen‐bonding interaction was strengthened when the CHI·HCl content in the blend films was 40%. The effects of deacetylation degree of KGM, acids (the solvent Chitosan dissolved in), temperature, and the mix ratio on the swelling behavior of the blend films were also studied. The blend film KC3 (CHI·HCl content in the blend films was 30%) had not only the highest equilibrium swelling degree (26 times) but also the highest tensile strength, and it could be regarded as a potential absorbent film material. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and self‐assembling behaviors of biotinylated pluronic/poly(lactic acid) biocompatible block copolymers in aqueous solutions
Authors: Li Zi Ling , Xiong Xiang Yuan , Li Yu Ping , Gong Yan Chun , Gui Xing Xing , Ou‐Yang Xing , Lin Hua Sheng , Zhu Lu Juan , Xie Ji Lei
Published: October 2009

Four kinds of Biotinylated Pluronic/PLA block copolymers were synthesized by two‐step reactions. Pluronic were firstly modified by biotin to obtain B‐Pluronic‐OH. Biotin‐Pluronic‐PLA block copolymers were then produced by ring‐opening polymerization of the monomer L‐lactide using Biotin‐Pluronic‐OH as the initiator and stannous octoate (Sn(Oct)2) as the catalyst. The self‐assembling behaviors of Biotin‐Pluronic‐PLA block copolymers in aqueous solutions were examined by fluorescence measurement, dynamic light scattering (DLS), and transmission electron microscopic (TEM) techniques. The size of Biotin‐F127‐PLA‐61, Biotin‐F87‐PLA, and Biotin‐P85‐PLA nanoparticles were determined to be 198, 229, and 257 nm, respectively, and their morphologies were found to be spherical micelles. Biotin‐F127‐PLA‐87 produces both spherical micelles and large compound micelles with the size of 127 and 906 nm. The cytotoxicity studies using human ovarian cancer cells OVCAR‐3 indicate that Biotin‐Pluronic‐PLA block copolymers have good biocompatibility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Biosynthesis and characterization of bacteria cellulose–alginate film
Authors: Kanjanamosit Nitisak , Muangnapoh Chirakarn , Phisalaphong Muenduen
Published: October 2009

A novel polysaccharide membrane containing alginate in bacterial cellulose matrix was synthesized by Acetobacter xylinum under static conditions using a culture medium supplementation with sodium alginate. By increasing alginate content, the bacterial cellulose–alginate (BCA) membrane was more hydrophilic and the film structure became denser with the smaller average pore size. Scanning electron microscope images displayed the deposits of alginate gel on the surfaces of the multilayer cellulose film. The declines in the tensile strength, the Young's modulus, and the elongation at break of the BCA membrane were dependent on the degree of alginate supplement. The BCA membrane showed higher water absorption capacity. The addition of alginate slightly affected the water vapor transmission rate but remarkably decreased the oxygen transmission rate of the membrane. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Value‐added derivatives of soda lignin from alfa grass (Stipa tenacissima). I. Modification and characterization
Authors: Nadji H. , Bedard Y. , Benaboura A. , Rodrigue D. , Stevanovic T. , Riedl B.
Published: October 2009

Alfa grass (Stipa tenacissima) is the only raw material for manufacturing paper pulp in Algeria, Tunisia, and Morocco. Soda lignin (SL) is obtained from black liquor (BL), a byproduct of manufacturing paper from alfa grass. This work was aimed at modifying SL and using it as a polymer lubricant. Modified SL was obtained in two steps: the precipitation of BL at pH 4 with sulfuric acid (2N) followed by the modification of SL by esterification using stearic anhydride (SA) dissolved in dioxane at 50°C for 8 h. The effects of different contents of SA on the hydrophobic properties and heat stability of modified SL were evaluated with contact angle analysis and thermogravimetric analysis. A commercial stearate used in plastic processing was chosen as the reference. Its thermal properties were ascertained with thermogravimetry, and its behavior was similar to that of the modified lignins. A structural comparison study was performed with Fourier transform infrared (FTIR) spectroscopy and solid‐state 13C‐NMR. The FTIR and 13C‐NMR results showed that there were significant differences between the main structures of SL samples reacted with 10, 30, or 100% (w/w) SA. The main part of the work consisted of modifying SL, evaluating the properties of the obtained products with respect to their use as lubricants, and comparing them to industrial lubricants. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Creep and stress relaxation modeling of vinyl ester nanocomposites reinforced by nanoclay and graphite platelets
Authors: Almagableh Ahmad , Raju Mantena P. , Alostaz Ahmed
Published: October 2009

This article discusses the viscoelastic behavior of a vinyl ester (Derakane 411‐350) reinforced with 1.25 and 2.5 wt % nanoclay and exfoliated graphite nanoplatelets during short‐term creep and relaxation tests with a dynamic mechanical analyzer. Linear viscoelastic models are generally composed of one or more elements such as dashpots and springs that represent the viscous and elastic properties. Stress relaxation data from the dynamic mechanical analyzer have been used to obtain the elastic parameters based on model constitutive equations. The standard linear solid model, which is a physical model, has been used for predicting the creep deformation behavior of the vinyl ester nanocomposites over a wide temperature range. Some correlations have been made with the mechanical model, such as the effect of temperature on the deformation behavior, which is well explained by the dashpot mechanism. At lower temperatures, higher creep compliance has been observed for the vinyl ester versus the nanocomposites, whereas at temperatures near the glass‐transition temperature of the vinyl ester, creep compliance in the nanocomposites is closer in magnitude to that for the vinyl ester. The creep response of the pure vinyl ester and its nanocomposites appears to be modeled reasonably well at temperatures lower than their glass‐transition temperatures. A comparison of the predictions and experimental data from the creep tests has demonstrated that this model can represent the long‐term deformation behavior of these nanoreinforced materials reasonably well. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of the vinyl concentration on the structural and rheological characteristics of peroxide‐modified high‐density polyethylenes
Authors: Aigbodion Aireguamen I. , Ressia Jorge A. , Ciolino Andrés E. , Failla Marcelo D. , Vallés Enrique M.
Published: October 2009

The effect of the hydrogenation of the terminal vinyl groups on the peroxide modification and rheological properties of high‐density polyethylene (HDPE) was investigated. The aim of the study was to determine exclusively the effect of the terminal vinyl groups on the peroxide crosslinking and rheological properties of HDPE with one polymer type. This was achieved by hydrogenation of the terminal vinyl groups of a commercial HDPE to obtain an identical material from a structural point of view, which differed only in the nature of the terminal unsaturations, and the comparison of its level of peroxide crosslinking with that of the original polymer. Hydrogenated and unhydrogenated polymer samples were modified at 170°C with different amounts of organic peroxide ranging from 125 to 5000 ppm. Changes in the molecular structure were determined by Fourier transform infrared spectroscopy, size exclusion chromatography, and rheological measurements. Hydrogenation of the terminal groups of the original polymer significantly reduced the rate of modification or crosslinking. The dynamic viscosity and elasticity increased with the level of peroxide modification. Unhydrogenated samples exhibited rapid increases in viscosity and elastic modulus, whereas their hydrogenated counterparts required about 500% of the amount of peroxide needed for the unhydrogenated sample to attain similar structural changes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Electrical and thermal properties of γ‐irradiated nitrile rubber/rice husk ash composites
Authors: Mohamed Rasha M. , Radwan Reda M. , Abdel‐Aziz Mohamed M. , Khattab Magdy M.
Published: October 2009

The effects of both the rice husk ash (RHA) loading and fumed silica (FS) loading on the structure, thermal stability, and electrical properties of acrylonitrile–butadiene rubber (NBR) composites were studied. The filler loading were chosen to be 5 and 20 phr for RHA and 5 and 30 phr for silica. Also, the effect of the γ‐irradiation dose (25 kGy) on these parameters was investigated. The structure and thermal stability were studied with X‐ray diffraction and thermogravimetric analysis techniques. Furthermore, some electrical parameters, such as the direct‐current electrical conductivity (σdc), activation energy (Ea), dielectric constant (ϵ′), and dielectric loss (ϵ″), were determined. The incorporation of both RHA and FS resulted in improved thermal stability after γ irradiation at 25 kGy. The loading of FS on NBR was shown to decrease σdc, ϵ′, and ϵ″ and increase Ea. On the other hand, the loading of RHA showed the opposite trend. Finally, γ irradiation of NBR composites filled with both fillers decreased the values of σdc, ϵ′, and ϵ″ for all the samples, which followed the trend for the unirradiated composites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Phase compatibility and barrier properties of ethylene/vinyl alcohol copolymer based hybrid materials
Authors: Nam Jae‐Do , Kim Seong Woo
Published: October 2009

An ethylene/vinyl alcohol copolymer (EVOH) with superior barrier properties was used as an organic component to prepare EVOH/SiO2 hybrid materials with improved gas barrier properties with a sol–gel method. As a silane coupling agent, 3‐isocyanatopropyl triethoxysilane (IPTES) was used to promote interfacial attraction between the organic EVOH segments and the inorganic silicate network in the hybrid. The phase compatibility was evaluated by analysis of Fourier transform infrared spectroscopy and phase morphology and the optical properties of the hybrids. We confirmed that the addition of the silane coupling agent IPTES up to some level of content resulted in enhanced phase compatibility and optical transparency of the nanostructured hybrid material with a homogeneous phase morphology exhibiting no microphase separation. For the preparation of the monolayer coated film, the biaxially oriented polypropylene substrate pretreated with a corona was coated with the hybrid sols by a spin‐coating method. The oxygen permeation behavior through the coated film was examined with various contents of the silane coupling agent IPTES and inorganic silicate precursor tetraethoxyorthosilicate in the hybrid system. Consequently, it was revealed that an optimum range of IPTES and tetraethoxyorthosilicate contents was required to produce high barrier EVOH/SiO2 hybrid materials with a stable homogeneous microstructure and enhanced optical transparency. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of the thin‐film thickness and crystallization temperature on the spherulitic structure of polymer thin films
Authors: Liu Jieping , Qiao Xiaoping , He Shuangai , Cao Qikun , Wang Hui
Published: October 2009

The spherulitic structure and morphology of poly(3‐hydroxybutyrate) (PHB) thin films crystallized from the melt were observed with a polarizing optical microscope. Depending on the thickness of the PHB thin film and crystallization temperature, banded and nonbanded spherulites could form. Reducing the thin‐film thickness and crystallization temperature was favorable for the formation of the banded structure. The morphology transition from banded spherulites to nonbanded spherulites was related to the ratio of the crystallization rate to the diffusion rate. The formation mechanism of the banded structure was examined with the discontinuity growth theory. A depletion zone was considered to appear periodically at the crystal growth front because of the slow diffusion rate, and this may have resulted in the banded spherulites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of a photoinitiator on the photochemical stability of poly(methyl methacrylate) studied with fourier transform infrared spectroscopy
Authors: Kaczmarek Halina , Gałka Piotr , Kowalonek Jolanta
Published: October 2009

Fourier transform infrared (FTIR) spectroscopy was used to investigate the effect of a commercial photoinitiator [2,2‐dimethoxy‐2‐phenylacetophenone (DMPA); Irgacure 651, Ciba, Basel, Switzerland] incorporated into poly(methyl methacrylate) (PMMA). Pure PMMA and modified PMMA (containing 5% DMPA) films were exposed to a xenon lamp in air. Qualitative and quantitative analyses of the recorded FTIR absorption spectra were done. This allowed us to determine the differences in the course of polymer photooxidative degradation occurring in PMMA and PMMA doped with DMPA. We found that the initiator added to polymer film enhanced the efficiency of the formation of the photooxidized products containing functional groups of different types, which could be distinguished by mathematical treatment of the FTIR spectra. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Vibration damping and electrical conductivity of styrene–butyl acrylate random copolymers filled with carbon black
Authors: Shamir D. , Siegmann A. , Narkis M.
Published: October 2009

Emulsion‐polymerized poly(styrene‐rand‐butyl acrylate) (St–BA) copolymers exhibit damping capabilities over a wide temperature range with changes in the monomer ratio. Blending copolymers of different compositions results in a multidamping peak, further widening the effective damping temperature range. Adding carbon black (CB) reduces the peak damping intensity but enhances damping at higher temperatures. The addition of dodecyl benzene sulfonic acid to an St–BA/CB aqueous dispersion improves the dispersion of CB in the polymer, reducing the percolation threshold and improving the conductivity while slightly affecting the mechanical behavior. The electrical properties of the St–BA/CB system are affected by the copolymer composition, influencing the polymer surface tension. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of poly(ϵ‐caprolactone)‐block‐poly(n‐butyl acrylate) by the combination of ring‐opening polymerization and atom transfer radical polymerization with Ti[OCH2CCl3]4 as a difunctional initiator. II. Synthesis and characterization of poly(ϵ‐caprolactone)‐block‐poly(n‐butyl acrylate) copolymers
Authors: Li Peichun , Xia Zhean , Zerroukhi Amar , Chen Jianding , Chalamet Yvan , Jeanmaire Thomas
Published: October 2009

The kinetics and controllability of the Ti[OCH2CCl3]4‐initiated atom transfer radical polymerization (ATRP) of n‐butyl acrylate were investigated. Then, with Ti[OCH2CCl3]4 as the initiator, poly(ϵ‐caprolactone)‐block‐poly(n‐butyl acrylate) (PCL‐b‐PBA) copolymers were synthesized by the combination of the ring‐opening polymerization (ROP) of ϵ‐caprolactone and ATRP of n‐butyl acrylate. With different sequential combinations of ROP and ATRP, three routes were used to synthesize PCL‐b‐PBA copolymers. The composition characterization results demonstrated that the first‐ROP‐then‐ATRP route was most efficient; it was followed by the in situ ATRP and ROP route and then the first‐ATRP‐then‐ROP route. Furthermore, with a Haake Rheomix reactor (Thermo Electron Corp., Karlsruhe, Germany), the PCL‐b‐PBA copolymers were in situ synthesized in a poly(methyl methacrylate) matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effects of annealing (solid and melt) on the time evolution of the polymorphic structure of polyamide 6
Authors: Zhao Xiong‐Yan , Zhang Bing‐Zhu
Published: October 2009

To understand whether and how the thermal history, especially the melting annealing, affects the polymorphism and thermal property of polyamide 6 (PA6), the temperature‐modulated differential scanning calorimetry technology was used to investigate the effects of thermal histories, including annealing temperature, annealing time, and cooling rate, on the polymorphic behavior and thermal property of PA6. It was found that longer annealing time and faster cooling rate favored the formation of α crystal when PA6 samples were annealed in the solid‐state at 175°C. As the annealing temperature was elevated to 195°C, faster cooling rate also favored the formation of α crystal, whereas longer annealing time was more favorable for the formation of γ‐form crystals. When PA6 samples were annealed in the melt‐state (245°C), however, although the α crystal was dominating crystalline phase, the formation of γ crystal was greatly enhanced with increasing annealing time and cooling rate. Moreover, a small endothermic peak was observed in the low‐temperature region in PA6 samples annealed at 175°C and 195°C, which might be related to the melting of microcrystals formed in the amorphous regions during annealing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of water‐glass‐based silica aerogel powder via with and without squeezing of hydrogels
Authors: Rani T. Sobha , Subha M. C. S. , Venkata Reddy G. , Kim Yong‐Ha , Ahn Young‐Soo
Published: October 2009

The present article describes the synthesis of water‐glass‐based silica aerogel powder via coprecursor method, using with and without squeezing, in drying technique. The present research was aimed to develop a simple, cost‐effective, and rapid drying process, i.e., squeezing through sol–gel synthesis. The physical and textural properties of the aerogel powder synthesized with and without squeezing process via ambient pressure drying (APD) have been studied and compared. For characterization of aerogel powder, we employed Brunauer, Emmett, and Teller, Barrett‐Joyner‐Halenda, and field emission scanning electron microscope techniques. The experimental results showed that the properties of the aerogel powder obtained by squeezing are superior to those dried in a furnace one. The squeeze‐dried aerogel powder exhibited lower tapping density (0.126 g/cm3) than furnace dried. Furthermore, textural investigations revealed that the aerogel powder has high‐specific surface area (752.3 m2/g), high porosity, low shrinkage, and uniform pore size distribution, which is obtained by squeezing process via APD. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study on mechanical properties of powder impregnated glass fiber reinforced poly(phenylene sulphide) by injection molding at various temperatures
Authors: Zhai Huan , Zhou Xiaodong , Fang Li , Lu Ai
Published: October 2009

The prepreg of continuous glass fiber reinforced poly(phenylene sulphide) (PPS) was prepared using the powder impregnation technique and cut into the pellets, in which the length of glass fibers was the same as the pellets. After injection molding, the mechanical properties were tested and the effects of the pellet length, fiber content, and thermal treatment on the mechanical properties at different temperatures were studied. It is found that the tensile strength and flexural strength of 6‐mm pellet sample are slightly higher than that of 3‐ and 12‐mm pellet samples. The tensile strength, flexural strength, and modulus decrease significantly with increasing the temperature. The notched Izod impact strength at 85ºC is higher than both at 25ºC and 205ºC. At 205ºC, the glass fiber reinforced PPS composites can still keep better mechanical properties. When the fiber content ranges from 0 to 50%, the mechanical properties increase with increasing the fiber contents at different temperatures, except the notched Izod impact strength do not further increase at 145 and 205ºC with raising the fiber content from 40 to 50%. Thermal treatment could improve the mechanical properties of the composites at higher serving temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effect of modified pluronic on the distribution of fillers in the polyvinyl chloride matrix
Authors: Rozik Nehad N. , Abd‐El Messieh S. L. , Abd‐El Nour K. N.
Published: October 2009

Pluronic was modified by using maleic anhydride (MA) and was characterized by means of FTIR and 1H NMR. Polyvinyl chloride (PVC) was blended with different contents of modified pluronic (MPL). After 20% by weight MPL, no significant change was noticed in either the electrical or the mechanical properties. The addition of 10 wt % MPL to PVC loaded with different contents of titanium oxide (TiO2) and sodium bentonite was chosen to act as a dispersing agent for the two types of fillers. This result was obtained through the measurements of permittivity ε′ and dielectric loss ε″ at the frequency range (102−105 Hz) in addition to the electrical conductivity (σ). According to Arrhenius equation, the activation related to both conductivity Eσ and relaxation time Eτ in addition to the experimental σo were found to confirm the validity of compensation law for the semiconducting PVC system. The increase of ε′ and ε″ by increasing filler content in the presence of 10% MPL in comparison with those before the addition of such concentration of MPL indicates a homogenous distribution of filler in the PVC matrix. This result finds further justification through the mechanical measurements and the scanning electron micrographs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Pervaporative studies using polyimide‐filled PDMS membrane
Authors: Garg P. , Singh R. P. , Pandey L. K. , Choudhary V.
Published: October 2009

The application of pervaporation (PV) to the removal of volatile organic from aqueous solutions has become very interesting in the last few years. It is caused by the increasing level of compounds, such as petrochemical solvents (benzene, toluene, and xylenes) or chlorinated solvents (trichloroethylene or tetrachloroethylene), which are polluting the natural environment. In this work, effects of polyimide (PI) (prepared by direct polycondensation of dianhydride and diamine followed by thermal cyclization of polyamic acid) filler on PV properties of poly(dimethyl siloxane) (PDMS) have been studied. PDMS membrane filled with PI was used for the separation of benzene (Bz) and toluene (Tol) from the diluted aqueous solution and the results were compared with the neat PDMS membrane of similar thickness. The PDMS‐PI membrane showed normalized flux (J′) upto 1.2 kg μm/m2h for Bz and 1.48 kg μm/m2h for Tol and selectivity of organics varies from 7.3 to 3.2 for Bz and 8.9 to 2.8 for Tol with increasing concentration of organics. Concentration of PI filler in PDMS varied 5–25% w/w. PI filler increases thermal as well as mechanical stability of filled PDMS membranes. PDMS membrane filled with 25% PI was chosen for the pervaporation studies. The membranes were characterized by FTIR, thermogravimetric analyser and scanning electron microscopy. The mechanical strength of PDMS filled with 25% w/w PI (SPI‐25) membrane was found to be 2.7 MPa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Development of biosensor for phenol detection using agarose–guar gum based laccases extracted from Pleurotus ostreatus
Authors: Kushwah Brajesh Singh , Bhadauria Seema
Published: October 2009

Laccases from Pleurotus ostreatus was extracted from the Shaken flask cultures of Pleurotus ostreatus grown at 25°C with continuous agitation (110 rpm.) in baffled 1000 mL Erlenmeyer flasks containing 200 mL medium. The basal GYP medium used for cultures contained 20 g glucose l−1, 5 g yeast extract l−1, 5 g peptone from casein l−1, and 1 g MgSO4.7H2O l−1. The pH was adjusted to 5.0 with H3PO4 before sterilization. The kinetics of oxidation reactions catalyzed by laccases was studied using 2,2′‐azino‐bis (3‐ethylbenzthiazoline‐6‐sulphonic acid). The laccases showed lower specific activity and higher activity in nonpolar organic solvents. A biosensor using laccases was constructed for the determination of phenol. The enzyme was extracted from Pleurotus ostreatus and entrapped in agarose–guar gum composite biopolymer matrix. Phenol was determined by direct reduction of biocatalytically liberated quinone species at −0.1 V versus Ag/AgCl (3M KCl). The response was found to be linear and concentration dependent.It has a shelf life of more than 2 months when stored at 4°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of the substitution degrees on the optical properties of cellulose acetates
Authors: Necula Adina Maria , Olaru Niculae , Olaru Liliana , Homocianu Mihaela , Ioan Silvia
Published: October 2009

Cellulose acetates with different substitution degrees possess a set of properties that makes them highly suitable for optical applications. This article discusses some of these properties, namely refractivity, dielectric properties, and transmittance. The contribution of the ratio between the molar refraction, which is proportional to the induced dipole moment, and the molar volume for the different atoms present in the studied polymers to the optical properties was investigated. The study illustrates the importance of such structural and compositional characteristics in tailoring some specific optical applications. Furthermore, optical transmission has been investigated in the 200–1000 nm range. To obtain the optical parameters, the approach proposed by Tauc for amorphous semiconductors has been used because of the similarity of the absorption edges. The values of pseudogap energy ranged between 3.44 and 4.70 eV, whereas those of Urbach energy were modified in the 18–37 meV range. All parameters determined have been related to the influence of the substitution degrees and of the synthesis condition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic behavior of photo‐polymerization of UV‐curable resins with carboxylic acid and amino groups
Authors: Kuo Kuo‐Huai , Chiu Wen‐Yen , Don Trong‐Ming
Published: October 2009

Photo‐polymerization behaviors of bisphenol‐A epoxy diacrylate (EPA) and six kinds of EPA‐derived resins containing different amounts of carboxylic acid, urethane, amide, and imide groups were studied by a photo differential scanning calorimetry. The dark polymerization was performed and pseudo‐steady state assumption of growing radicals was made to obtain the kinetic constants for propagation, bimolecular termination, monomolecular termination, and the concentration of growing radicals of different resins as a function of extent of reaction. Compared with EPA, it was found that the rate of polymerization and kinetic constants of the six resins were relatively small because the mobility of reacting species in resins was restricted by carboxylic acid, urethane, amide, and imide groups. Finally, three different photo‐initiators were used to initiate the polymerization, and their kinetic behaviors were compared. The effect of tertiary amine group of photo‐initiator on the rate of polymerization of resins having carboxylic acid group and the initiator efficiency were discussed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and properties of electrospun PAN/Fe3O4 magnetic nanofibers
Authors: Wang Biao , Sun Ying , Wang Huaping
Published: October 2009

Polyacrylonitrile (PAN)/Fe3O4 composite nanofibers were prepared via the electrospinning of the PAN spinning solutions with magnetite Fe3O4 nanoparticles. The experimental results showed that the morphology and diameter of the nanofibers strongly depended upon concentrations of PAN and salt additives in the spinning solutions. A suitable PAN concentration and LiCl additives could effectively prevent the occurrence of beads in the electrospinning process and affected the diameters of the electrospun nanofibers. The breaking strength and breaking strain decreased when the magnetite Fe3O4 nanoparticles were incorporated. The prepared PAN/Fe3O4 nanofibers were superparamagnetic at room temperature. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Investigation of cytotoxic effects of new maleic anhydride binary and ternary copolymers on L929 mouse fibroblasts
Authors: Can Hatice Kaplan , Gürpinar Özer Aylin , Onur Mehmet Ali , Rzaev Zakir M.O. , Güner Ali
Published: October 2009

The purpose of this study was to investigate the cytotoxic effects of poly(MA‐alt‐AA) and poly [MA‐co‐AA‐co‐(VA)] in cell culture model. Complex‐radical copolymerization (CTC) of maleic anhydride (MA), and acrylic acid (AA) and ternary polymerization of (MA), vinyl acetate (VA) and AA, considered as acceptor−donor−acceptor systems, were carried out. For the cytotoxicity study, cells were incubated at initial density of 50,000 cells/mL in 24‐well plates. After 24‐h incubation, the culture medium was removed and fresh medium containing five different dilutions of polymers were added separately. Cell viability and proliferation were assessed on 1st and 5th days. Apoptosis was assessed using propidium iodide/acridine orange (PI/AO) staining at the 1st and 5th days of incubation. Kruskal‐Wallis test was applied to compare the effects of different dilutions on cell viability at each evaluation period. The results showed that there were differences between co‐ and terpolymer in view of cell proliferation and apoptotic response. The results suggest that functional groups in co‐ and terpolymer group may cause apoptotic cell death without effecting cell proliferation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Multifunctional formaldehyde resins as curing agent for epoxy resins
Authors: Mustata Fanica , Bicu Ioan
Published: October 2009

Formaldehyde resins (FR) at 1/1/2 molar ratios of monomers (Cl‐phenol/amino monomers/p‐formaldehyde) were synthesized under acid catalysis. The obtained resins were characterized using elemental analysis, FTIR and RMN spectroscopic methods, being used as crosslinking agents for epoxy resin formulations. The curing of epoxy resins with FR were investigated. The glass transition temperature (Tg) and decomposition behavior of crosslinked resins were studied by differential scanning calorimetry (DSC) and thermogravimetric (TGA) techniques. All DSC scans show two exothermic peaks, which implied the occurrence of cure reactions between epoxy ring and amine or carboxylic protons, in function of chemical structures of FR. The crosslinked products showed good thermal properties, high glass transitions, and low water absorption. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Electrospun poly(D,L‐lactide) and polyaniline scaffold characterization
Authors: McKeon K. D. , Lewis A. , Freeman J. W.
Published: October 2009

Neuromuscular disease or peripheral nerve damage can interrupt muscle contraction, but tissue engineered constructs can be created to combat this problem. Electrospinning provides a way to create a degradable nonwoven mesh that can be used to culture cells and tissues. Conductive polymers can be blended with other polymers to provide an electrical current to increase cell attachment, proliferation, and migration. We electrospun several polyaniline and poly(D,L‐lactide) (PANi/PDLA) mixtures at different weight percents including the following PANi‐PDLA solutions (w/v): 24% (83% PDLA/17% PANi), 24% (80% PDLA/20% PANi), 22% (75%PDLA/25% PANi), 29% (83% PDLA/17% PANi), and 29% (80% PDLA/20% PANi). Only the 75/25 electrospun scaffold was able to conduct a current of 5 mA. The calculated electrical conductivity for this scaffold was 0.0437 S/cm. Primary rat muscle cells were cultured on all three of the scaffolds and on tissue culture polystyrene as a positive control. Although the scaffolds degraded during this process, cells were still able to attach and proliferate on each of the different scaffolds. The cellular proliferation measurements showed no significant difference between the four groups measured. The conductivity and cellular behavior demonstrate the feasibility of fabricating a biocompatible, biodegradable, and electrically conductive PDLA/PANi scaffold. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication and characterization of a solid polymeric electrolyte of PAN‐TiO2‐LiClO4
Authors: Rahman M. Y. A. , Ahmad A. , Ismail L. H. C. , Salleh M. M.
Published: October 2009

The ionic conductivity of PAN‐TiO2‐LiClO4 as a function of TiO2 concentration and temperature has been reported. The electrolyte samples were prepared by solution casting technique. Their conductivity was measured using the impedance spectroscopy technique. The highest room temperature conductivity of 1.8 × 10−4 S cm−1 was obtained at 7.5 wt % of TiO2 filler. It was observed that the relationship between temperature and conductivity were linear, fitting well in Arrhenius and not in Vogel‐Tamman‐Fulcher equation. The pre‐exponential factor, σ0 and Ea are 1.8 × 10−4 S cm−1 and 0.15 eV, respectively. The conductivity data have been supported by differential scanning calorimeter (DSC) analysis. DSC analysis showed that there was a significant change in glass transition temperature (Tg) with the filler concentration. The SEM micrograph revealed that the TiO2 particles are dispersed in the electrolyte, thus enhancing its conductivity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Low‐phosphorus maleic acid and sodium ρ‐styrenesulfonate copolymer as calcium carbonate scale inhibitor
Authors: Wang Chen , Zhu Deyi , Wang Xikui
Published: October 2009

In this article, a multifunctional and environment‐friendly agent for industry circulation cooling water, maleic acid and sodium ρ‐styrenesulfonate copolymer containing low‐phosphorus was synthesized in aqueous solution with hypophosphorous acid/hydrogen peroxide as redox initiators. The effects of monomer feed ratio, temperature, dose of hypophosphorous acid, and drop speed of hydrogen peroxide on calcium carbonate inhibition were investigated, and the experimental conditions were optimized using orthogonal method. The composition and structure of the copolymer were analyzed by enery‐dispersive X‐ray analysis, fourier transform infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The results of the static scale inhibition tests showed that the copolymer was effective in inhibiting the formation of calcium carbonate scale. The calcium carbonate precipitates formed in the static tests were examined by scanning electronic microscopy and X‐ray diffraction spectra. The results indicate that in the presence of the copolymer the calcium carbonate precipitate is the mixture of calcite and vaterite that could be stabilized kinetically in the presence of the copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
pH‐sensitive hydrogels based on bovine serum albumin for anticancer drug delivery
Authors: El‐Sherif Hazem , El‐Masry Mansour , Taleb Manal F. Abou
Published: October 2009

Protein conjugates consisting of hydroxyethyl methacrylate and acrylic acid monomers in the presence of bovine serum albumin (BSA) were prepared by gamma irradiation to examine the potential use of these hydrogels in the controlled drug release systems. The study parameter was the BSA content in the as‐prepared conjugates. Polymers were characterized with FTIR, scanning electron microscopy (SEM), and swelling studies. The polymerization reaction caused the rearrangement of the BSA carbonyl hydrogen bonding and finally led to the modification of the BSA secondary structure as proved by FTIR. SEM proved that the prepared conjugates matrices are porous, with a three‐dimensional interconnected microstructure. The swelling kinetics of the hydrogels and the release dynamics of an anticancer model drug (flutamide) have been studied. High equilibrium swelling values, up to 1550%, could be observed and were correlated with the increase in pH, temperature, and BSA content. The mechanism of swelling changed from Fickian to non‐Fickian by reducing the acidity of the medium. This study proved that there is a direct relationship between the protein content in the conjugates and both the loaded and the released drug. These pH responsive conjugates may be exploited for the delivery of flutamide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of UV‐curable/alkali‐soluble dispersants used for black photoresist with a high loading of carbon black
Authors: Kuo Kuo‐Huai , Chiu Wen‐Yen , Don Trong‐Ming
Published: October 2009

This research synthesized a functional dispersant, not only providing a good dispersion of carbon black (CB) but also possessing ultraviolet (UV)‐curable and alkali‐soluble properties, by a two‐step process. Firstly, bisphenol‐A epoxy diacrylate was reacted with benzophenone tetracarboxylic dianhydride at different molar ratios to obtain UV‐curable/alkali‐soluble resins. In the second step, these resins would possess dispersion ability of CB by reaction with an isocyanate‐containing methacrylate. The prepared dispersants were evaluated by their dispersion ability and the light absorption property of CB. The results showed that one of the dispersants was able to disperse CB in the solvent up to 10 wt % with a mean particle size about 100 nm. This particular dispersant had a moderate amount of amino‐containing groups (such as urethane, amide, and imide) serving as anchoring sites on CB, and a sufficiently long chain (Mn ∼ 2600) to provide a steric repulsion among CB particles. The advantage of this CB/dispersant system is that no other curable resins are needed. By using a suitable photoinitiator, the present CB/dispersant system could reach a polymerization rate of 1.05 × 10−3 (s–1), and a black pattern of 10 μm in width on a glass substrate was obtained through an UV‐lithography process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010