bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of copolymers of poly(ethylene terephthalate) and cyclohexane dimethanol in a semibatch reactor (including the process model)
Authors: Sepehri Sanam , Rafizadeh Mehdi , Afshar‐Taromi Framarz 
Published: May 2009

AbstractAlthough poly(ethylene terephthalate) (PET) has excellent basic properties, this polymer tends to crystallize rapidly and has a rather high melting temperature, a low glass‐transition temperature, and low impact on notched articles for some potential applications. Copolymerization is a reasonable method for improving the properties of PET. 1,4‐cyclohexane dimethanol (CHDM) is one of the most important comonomers for PET. In this research, PET and PET copolymers containing 5–30% CHDM were prepared from comonomer mixtures by two‐step melt polycondensation. The copolymers were synthesized in a home‐made laboratory setup. The first synthesis step was conducted under pressure, and the second was performed in vacuo at a high temperature (230–290°C). The microstructure of the synthesized copolymers was studied with Fourier transform infrared and nuclear magnetic resonance. The comonomer content in the polymer chain was determined from the nuclear magnetic resonance spectrum. The presence of the comonomer in the copolymer chain was random. Differential scanning calorimetry was used to study the thermal properties of the copolymers to detect changes in the polymer properties. CHDM reduced the heat of fusion and melting and glass‐transition temperatures of the PET copolymers. Process modeling was performed with mass balances of different functional groups and species. Equations of mass balances were integrated numerically. Numerical simulation and experimental results were in very good agreement. By modeling, the effects of the reaction temperature and feed molar ratio on the conversion and formation of diethylene glycol were studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of polymer‐grafted natural nanocrystals on the structure and mechanical properties of poly(lactic acid): A case of cellulose whisker‐graft‐polycaprolactone
Authors: Lin Ning , Chen Guangjun , Huang Jin , Dufresne Alain , Chang Peter R. 
Published: May 2009

AbstractIn this work, polysaccharide nanocrystals—rodlike cellulose whiskers (CWs)—were surface‐grafted with polycaprolactone (PCL) via microwave‐assisted ring‐opening polymerization, and filaceous cellulose whisker‐graft‐polycaprolactone (CW‐g‐PCL) nanoparticles were produced. Moreover, the resultant nanoparticles were incorporated into poly(lactic acid) (PLA) as a matrix, and they showed superior function for enhancing the mechanical performance of PLA‐based materials in comparison with platelet‐like nanoparticles of starch nanocrystal‐graft‐PCL. The optimal loading level of CW‐g‐PCL was 8 wt %, and this resulted in simultaneous enhancements of the strength and elongation of approximately 1.9‐ and 10.7‐fold, respectively, over those of the neat PLA material. In this case, the rigid CW nanoparticles contributed to the endurance of higher stress, whereas the grafted PCL chains improved the association between the PLA matrix and the CW‐g‐PCL filler and hence facilitated the transfer of stress to the rigid CW nanoparticles. Furthermore, such a fully biodegradable PLA‐based nanocomposite shows great potential for environmentally friendly materials because of its high mechanical performance. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Self‐reinforcing isotactic polypropylene prepared using crystallizable solvents
Authors: Yoon Joonsung , McCarthy Thomas J. , Lesser Alan J. 
Published: May 2009

AbstractA new approach to reinforce and toughen isotactic polypropylene (iPP) with improved processability is evaluated. The concept involves using a crystallizable solvent that, at process temperatures melts, is miscible with the polymer thereby reducing its process viscosity. As the polymer cools, the solvent undergoes thermally induced phase separation (TIPS) to produce crystallites that increase the modulus of the solid through reinforcement and promote an increase in impact resistance by mechanisms similar to rubber‐toughened materials. Tetrabromobisphenol‐A (TBBPA) is introduced to iPP that forms a homogeneous mixture at elevated temperature and acts as a processing aid, but undergoes phase separation and subsequent crystallization upon cooling to form rigid particles which, in turn, acts as a toughening agent at room temperature. A phase diagram constructed with Flory‐Huggins solution thermodynamics shows good agreement with the experimental results. The steady state shear viscosity decreases as TBBPA content increases for the mixtures in melt state, indicating improved processability. The decrease in viscosity enhances crystallization rate of iPP significantly, most likely due to increased diffusivity, while the structure of iPP crystals remain unchanged. Tensile tests show that as TBBPA content increases (up to 15 wt %), the yield stress decreases while elongation at break increases. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Laboratory investigation of the properties of asphalt modified with epoxy resin
Authors: Yu Jianying , Cong Peiliang , Wu Shaopeng 
Published: May 2009

AbstractEpoxy asphalts were prepared by mixing styrene–butadiene–styrene (SBS) modified asphalt with epoxy resin. The curing process and morphology of epoxy asphalts were characterized by infrared spectroscopy and fluorescent microscope, respectively. The effects of epoxy resin contents, ratio of curing agent to epoxy resin and curing temperature on properties of epoxy asphalt were investigated. Results indicated that epoxy resin and epoxy asphalt showed similar curing efficiency. Epoxy asphalts can be cured at 120 or 60°C and its viscosity at 120°C can meet the demands of asphalt mixture mixing and paving. The chemical reaction of epoxy resin in epoxy asphalt is slow and reaction occurs not only with the curing agent but also carboxylic acid in epoxy asphalt. The microstructure of epoxy asphalt transforms from the dispersed structure to networks structure with epoxy resin content increasing and phase transition starts when 30 wt % epoxy resin present in asphalt. The softening point and tensile strength of epoxy asphalt increased with epoxy resin contents increasing. The softening point and tensile strength of epoxy asphalt were markedly improved when epoxy resin content was more than 30 wt %, which is attributed to formation of continuous structure of epoxy resin. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study on partially oxidized sodium alginate with potassium permanganate as the oxidant
Authors: Lu Lingbin , Zhang Ping , Cao Yang , Lin Qiang , Pang Sujuan , Wang Huaming 
Published: May 2009

AbstractIn this article, partial oxidation of sodium alginate with potassium permanganate (KMnO4) was researched successfully. The effects of KMnO4 on the properties of partially oxidized sodium alginate were discussed. It was found that the degree of oxidation and degradation rate of sodium alginate could be controlled by oxidation conditions, as monitored by the reduction of viscosity and decrease of molecular weight. This work provides a new method to obtain partially oxidized alginate and to improve degradability of alginate for biomedical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Structure and properties of closed‐cell foam prepared from irradiation crosslinked silicone rubber
Authors: Liu Pengbo , Liu Daolong , Zou Huawei , Fan Ping , Xu Wen 
Published: May 2009

AbstractSilicone rubber foam was prepared through crosslinking with electron beam irradiation and foaming by the decomposing of blowing agent azobisformamide (AC) in hot air. The crosslinking and foaming of silicone rubber was carried out separately, which was different from the conventional method of chemical crosslinking and foaming. After foaming, the silicone rubber foam was irradiated again to stabilize the foam structure and further improve its mechanical properties. The effects of irradiation dose before and after foaming, and the amount of blowing agents on the structure and properties of silicone rubber foam were studied. The experimental results show that with the increase of AC content, the average cell diameter of silicone rubber foam increases a little, the foam density decreases to a minimum value when AC content is 10 phr. With the increase of irradiation dose before foaming from 10 to 17.5 kGy, the cell nucleation density of silicone rubber foam increases, the average cell diameter decreases, and the foam density increases. With the increase of irradiation before foaming, the tensile strength, tensile modulus, and the elongation at break of the silicone rubber foam increase. Through irradiation crosslinking again after foaming, the foam density is decreased and the mechanical properties of silicone foam are further improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Modification of ramie fiber with an amine‐containing polymer via atom transfer radical polymerization
Authors: Liu Zhao‐Tie , Sun Chang'an , Liu Zhong‐Wen , Lu Jian 
Published: May 2009

AbstractThe covalent bonding of tertiary amine 2‐(dimethylamino)ethyl methacrylate to ramie fiber via atom transfer radical polymerization was obtained with a brominated initiator and the catalyst CuCl/1,10‐phenanthroline. The results reveal that poly[2‐(dimethylamino)ethyl methacrylate] (PDMAEMA) was successfully immobilized on the surface of the ramie fiber in a controlled polymerization. After the grafting with PDMAEMA, the crystal structure of cellulose I in the ramie fiber was still preserved, and the lateral size of the microfibrils, calculated on the basis of plane 002, was slightly increased. As a demonstration of possible applications, the modified fiber was dyed with CI Reactive Red 2. The dye uptake, which almost linearly increased with increasing molecular weight of PDMAEMA attached on the ramie fiber, was raised to be over 15 times that of the raw fiber. The reason was that the reactivity between the tertiary amines in PDMAEMA and the dichlorotriazinyl group in the dye molecules was much higher than that between the hydroxyl groups in the ramie fiber and the reactive groups in the dye molecules. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polymers based on N,N‐diglycidylaniline. I. Investigations of the curing kinetics by dynamic differential scanning calorimetry measurements
Authors: Janeczek Henryk , Siwy Mariola , Schab‐Balcerzak Ewa 
Published: May 2009

AbstractN,N‐Diglycidylaniline was reacted with aniline (yielding polymer EP‐1) and the newly synthesized chromophore 4‐(phenylazo)aniline (yielding polymer EP‐2). The curing kinetics of these two epoxy resin systems was studied in dynamic experiments by means of differential scanning calorimetry. Kinetic parameters such as the activation energy and frequency factor were estimated with the Ozawa method [E(O) and A(O), respectively], the Kissinger method [E(K) and A(K), respectively], and the modified Avrami method [E(A) and A(A), respectively]. The activation energy and frequency factor of EP‐1 were much lower than those of EP‐2 estimated with the Ozawa, Kissinger, and Avrami methods. The activation energy and frequency factor for EP‐1 determined with the Ozawa method [E(O) = 55.8 kJ/mol, A(O) = 10 × 103 1/s] and the Avrami method [E(A) = 56.4 kJ/mol, A(A) = 9.2 × 103 1/s] were higher than those determined with the Kissinger method [E(K) = 51.0 kJ/mol, A(K) = 2 × 103 1/s]. In the case of EP‐2, the kinetic parameters calculated with the Ozawa model [E(O) = 140.4 kJ/mol, A(O) = 12.3 × 1013 1/s] and the Kissinger model [E(K) = 139.9 kJ/mol, A(K) = 10.9 × 1013 1/s] were higher than those calculated with the Avrami model [E(A) = 130.4 kJ/mol, A(A) = 7.9 × 1012 1/s]. The obtained polymers were characterized with Fourier transform infrared, 1H‐NMR, differential scanning calorimetry, and ultraviolet–visible spectroscopy. The polymers exhibited low glass‐transition temperatures in the range of 57–79°C and good solubility in common organic solvents. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Morphology, mechanical properties, and thermal stability of poly(L‐lactic acid)/poly(butylene succinate‐co‐adipate)/silicon dioxide composites
Authors: Wang Ruyin , Wang Shifeng , Zhang Yong 
Published: May 2009

AbstractPoly(butylene succinate‐co‐adipate) (PBSA) and two types of SiO2 (hydrophilic or hydrophobic) were used to modify poly(L‐lactic acid) (PLLA). The mechanical properties, rheological and thermal behavior, phase morphology, and thermal stability of PLLA/PBSA/SiO2 composites were investigated. The impact strength, flexural strength, and modulus of PLLA/PBSA blends increased after the addition of hydrophobic SiO2 without decreasing the elongation at break, and the elongation at break monotonically decreased with increasing hydrophilic SiO2 content. The melt elasticity and viscosity of the PLLA/PBSA blend increased with the addition of SiO2. The hydrophilic SiO2 was encapsulated by the dispersed PBSA phase in the composites, which led to the formation of a core–shell structure, whereas the hydrophobic SiO2 was more uniformly dispersed and mainly located in the PLLA matrix, which was desirable for the optimum reinforcement of the PLLA/PBSA blend. The thermogravimetric analysis results show that the addition of the two types of SiO2 increased the initial decomposition temperature and activation energy and consequently retarded the thermal degradation of PLLA/PBSA. The retardation of degradation was prominent with the addition of hydrophobic SiO2. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Alkaline‐developable, chemically amplified, negative‐type photosensitive polyimide based on polyhydroxyimide, a crosslinker, and a photoacid generator
Authors: Saito Yuta , Mizoguchi Katsuhisa , Higashihara Tomoya , Ueda Mitsuru 
Published: May 2009

AbstractA chemically amplified photosensitive polyimide based on polyhydroxyimide (PHI) from cyclobutanetetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)bis(2‐aminophenol), 4,4′‐methylenebis[2,6‐bis(hydroxymethyl)phenol] (MBHP) as a crosslinker, and (5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐(2‐methylphenyl)acetonitrile (PTMA) as a photoacid generator was developed to obtain the abilities of low temperature patterning, low dielectric constant, and high sensitivity. The chemically amplified photosensitive polyimide, consisting of PHI (70 wt %), MBHP (20 wt %), and PTMA (10 wt %), showed a high sensitivity (D0.5) of 5.9 mJ/cm2 and a good contrast (γ0.5) of 3.9, respectively, producing a clear negative‐tone line‐and‐space pattern with 6‐μm resolution. Furthermore, the chemically amplified photosensitive polyimide showed a high transparency in the i‐line region and a low dielectric constant of 2.54. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction
Authors: Antilén M. , Armijo F. 
Published: May 2009

AbstractA novel and simple electrode with rapid preparation was developed with humic acid (HA) and polypyrrole (PPy) films. The method for modified electrode preparation embraced the abrasive transfer technique on a paraffin‐impregnated graphite electrode (PIGE) followed by the electrochemical incorporation of a PPy polymeric film upon bare PIGE and PIGE/HA electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry were used for the study of the modified electrodes. Morphological characterization was performed by scanning electron microscopy. The obtained results demonstrated that the presence of HA did not affect the electrical properties of the system but indeed provoked changes in the polymer morphology, turning it more granular. Next, PIGE/HA/PPy was tested in arsenic solutions [As(V)] because arsenic contamination of water is an important worldwide environmental issue because of the sources of arsenic contamination of water come from both natural processes and anthropogenic activities. The modified electrode displayed good and reversible extraction properties toward the analyte in acid medium and was 18% more efficient than a previously reported PPy‐modified electrode (PIGE/PPy). From an environmental standpoint, this novel application of conductive polymer properties with the chelating capacity of humic substances constitutes a first step in the development of more efficient technologies for the removal of contaminants present in soil–water media. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties of styrene–butadiene–styrene block copolymer composites filled with calcium carbonate treated by liquid polybutadienes
Authors: Song Xuefang , Yoshino Hidetake , Shibata Hiroshi , Nagatani Asahiro , Ueda Yasukiyo 
Published: May 2009

AbstractThe factors influencing the mechanical properties of styrene–butadiene–styrene block copolymer (SBS) composites filled with liquid polybutadiene (LB)‐surface‐treated calcium carbonate (CaCO3) were investigated with respect to the molecular structure of the LB, the amount of the LB adsorbed on the CaCO3 surface, the heat treatment conditions, and the surface treatment method. The mechanical properties, such as the modulus, tensile strength at break, tear strength, storage modulus, and tension set, of the SBS composites were improved remarkably through the filling of CaCO3 surface‐treated with a carboxylated LB with a high content of 1,2‐double bonds. The heat treatment of LB–CaCO3 in air was also effective in enhancing such properties. When SBS, CaCO3, and LB were directly blended (with the integral blend method), secondary aggregation of CaCO3 took place, and the mechanical properties of the composite were significantly lower. In the integral blend method, LB functioned as a plasticizer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of structural variables on AUL and rheological behavior of SAP gels
Authors: Ramazani‐Harandi M. J. , Zohuriaan‐Mehr M. J. , Yousefi A. A. , Ershad‐Langroudi A. , Kabiri K. 
Published: May 2009

AbstractThe swelling properties of superabsorbent polymers (SAPs) under real conditions are extremely important for selecting the material suitable for a given application, e.g. feminine napkin or agriculture. This new practical research represents deeper synthetic and physicochemical studies on the structure–property relation in acrylic SAP hydrogels and composites. Thus, the values of saline‐absorbency under load (AUL; a measurable simulation of the real circumstances of SAP applications, at pressures 0.3–0.9 psi) were measured for the SAP or SAP composite samples prepared under different conditions, i.e. type and content of crosslinker, type and concentration of initiator, percentage of inorganic filler (kaolin), and type and percentage of porosity generators. The samples were subsequently used to determine the rheological and morphological characteristics. Dynamic storage modulus (G′) measurements were carried out at constant strain in a wide range of frequency. Linear correlations were frequently found to be active between AUL and G′ data over the rubber‐elastic plateau. Thus, for a given SAP: AUL = ktotalG′ + C. The coefficient k total is a function of (nature and content of crosslinker, initiator, inorganic component, particle morphology, etc.). Therefore, the easily measured AUL values could be simply correlated to the main synthesis variables and molecular structure of SAP gels through a rheological material function (G′). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Glass transition and cold crystallization in carbon dioxide treated poly(ethylene terephthalate)
Authors: Shieh Yeong‐Tarng , Lin Yu‐Sheng 
Published: May 2009

AbstractAn amorphous poly(ethylene terephthalate) (aPET) and a semicrystalline poly(ethylene terephthalate) obtained through the annealing of aPET at 110°C for 40 min (aPET‐110‐40) were treated in carbon dioxide (CO2) at 1500 psi and 35°C for 1 h followed by treatment in a vacuum for various times to make samples containing various amount of CO2 residues in these two CO2‐treated samples. Glass transition and cold crystallization as a function of the amount of CO2 residues in these two CO2‐treated samples were investigated by temperature‐modulated differential scanning calorimetry (TMDSC) and dynamic mechanical analysis (DMA). The CO2 residues were found to not only depress the glass‐transition temperature (Tg) but also facilitate cold crystallization in both samples. The depressed Tg in both CO2‐treated poly(ethylene terephthalate) samples was roughly inversely proportional to amount of CO2 residues and was independent of the crystallinity of the poly(ethylene terephthalate) sample. The nonreversing curves of TMDSC data clearly indicated that both samples exhibited a big overshoot peak around the glass transition. This overshoot peak occurred at lower temperatures and was smaller in magnitude for samples containing more CO2 residues. The TMDSC nonreversing curves also indicated that aPET exhibited a clear cold‐crystallization exotherm at 120.0°C, but aPET‐110‐40 exhibited two cold‐crystallization exotherms at 109.2 and 127.4°C. The two cold crystallizations in the CO2‐treated aPET‐110‐40 became one after vacuum treatment. The DMA data exhibited multiple tan δ peaks in both CO2‐treated poly(ethylene terephthalate) samples. These multiple tan δ peaks, attributed to multiple amorphous phases, tended to shift to higher temperatures for longer vacuum times. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Xanthate‐mediated polymerization of styrene on hyperbranched polyethylenimine: Synthesis, characterization, and guest‐encapsulating property
Authors: Wan Decheng , Yang Zhenglong , Pu Hongting , Zhao Jingxia , Yang Genjin 
Published: May 2009

AbstractHyperbranched polyethylenimine (HPEI) is a highly polar, multifunctional polymer bearing active amines throughout its globular structure. In this article, the amino protons, which were incompatible with living radical polymerization techniques, were alkylated with propylene oxide, leading to tertiary amines and hydroxyls, and part of the hydroxyl groups were further transformed into xanthate groups. The HPEI‐xanthate could mediate the polymerization of styrene, leading to a star‐like, multiarm amphiphilic polymer. It was found that the polymerization was a hybrid of living and conventional radical processes. The resulting amphiphilic, core‐shell‐structured polymer existed as a unimolecular micelle (UIM) in apolar solvent and could irreversibly encapsulate water‐soluble anionic dyes. At high pH, the encapsulated dyes could be partly released. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Monitoring tourism schooners observing estuarine dolphins (Sotalia guianensis) in the Estuarine Complex of Cananéia, south‐east Brazil
Authors: Filla Gislaine de Fatima , Monteiro‐Filho Emygdio Leite de Araujo 
Published: May 2009

Abstract
Surveys were carried out between December 2004 and March 2006 on board tourism schooners to detect possible impacts due to tourist activities on estuarine dolphins (Sotalia guianensis) in the Estuarine Complex of Cananéia.
The estuarine dolphins exhibited different reactions according to the different periods of time that the boats remained close to them: the longer the period, the estuarine dolphins reacted less negatively, and for periods between 2 and 30 min, more positive reactions were observed.
Estuarine dolphin reactions also varied according to the different procedures followed by the skippers. The approach methods considered ‘correct’ resulted in a positive reaction from 97% of the animals encountered and 100% of occasions where there were no apparent reactions.
Direct approaches to within less than 50 m were responsible for a large number of negative reactions from the estuarine dolphins. Procedures classified as ‘chasing’ and ‘direct approach with no intention of stopping’ had a 100% negative reaction. If the skippers used a correct approach, estuarine dolphins reacted positively or did not show any reaction.
Copyright © 2009 John Wiley & Sons, Ltd.