bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetic expression for the isothermal crystallization of poly(3‐hydroxybutyrate)–11%poly(3‐hydroxyvalerate)
Authors: Cyras Viviana P. , Rozsa Chavati , Galego Norma , Vázquez Analía 
Published: September 2004

AbstractThe use of polyhydroxyalkanoates as a biodegradable semicrystalline polymer is currently increasing. The prediction of crystallinity profiles produced in part with this polymer requires the knowledge of the kinetic expression. In the present article, a kinetic expression of the isothermal melt crystallization of poly(3‐hydroxybutyrate)–11%poly(3‐hydroxyvalerate) [P(HB‐co‐11%HV)] was studied in two temperature ranges, close to the melting point and close to the glass transition. Melting behavior and molecular mobility of the amorphous phase were analyzed as a function of crystallization temperatures by performing calorimetric experiments. The Avrami equation was used and the activation energy of the crystal nucleation and growth were obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1657–1661, 2004
Free radical polymerization kinetics of monomers functionalized with AsO(OH)2 in aqueous media
Authors: Percino M. J. , Chapela V. M. , Jiménez A. 
Published: September 2004

AbstractThe free radical polymerization kinetics of the isomer sodium salts of o‐ and p‐methacryloylaminophenylarsonate in aqueous solution have been studied using a dilatometric method. The polymerizations, initiated with potassium persulfate, were carried out at a constant monomer initial concentration of 0.50 mol/L and the initiator initial concentration was fixed at one of the following: 1.00, 2.00, 5.00, 8.00, or 10.00 (× 10−3 mol/L). Another set of polymerizations were carried out at a constant initiator initial concentration of 2 × 10−3 mol/L and the monomer initial concentration was fixed at one of the following: 0.20, 0.30, 0.50, 0.70, or 1.00 (mol/L). The polymerization reactions were conducted isothermally at 70°C. The order with respect to initiator was consistent with the classical kinetic rate equation, while the order with respect to monomer was greater that unity. The effects of temperature on the polymerization rate were also investigated and the activation energy gave values of 20.66, 22.68, and 23.22 kcal mol−1 K−1 over a temperature range of 50–70°C. For the case of o‐methacryloylaminophenylarsonic acid monomer, its kinetic study was carried out in DMF as solvent and AIBN initiator. p‐Methacryloylaminophenylarsonic acid was too insoluble in DMF to be studied. The polymers obtained were characterized by H‐NMR, IR, and viscosity. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1662–1669, 2004
Synthesis and properties of collagen/polylactic acid blends
Authors: Yang Xiaoqiang , Yuan Minglong , Li Wei , Zhang Gaoyong 
Published: September 2004

AbstractPolylactic acid (PLA) is a biodegradable aliphatic polyester that is suitable for use in many fields related to medical treatment. This article reviews the glass transition temperature (Tg), the biodegradable rate of PLA blended with collagen (Col), and its mechanical properties through tensile, bending and impact testing, thermal analysis (DSC), scanning electron microscopy (SEM), and enzymatic hydrolysis. The results of the mechanical and SEM examination demonstrated partial biocompatibility. The Tg and crystallinity (xc) of the blends decreased with increasing collagen content. The tensile strength and bending strength changed from 53.826Mpa and 102.261Mpa to 11.707Mpa and 24.994Mpa, respectively. It was also found that the enzymatic hydrolysis rate of PLA increased with increasing collagen content. The weight of the blends decreased to half of the original weight after more than five weeks. Viscosity([η]) and molecular weight (Mv) changed slowly in the period of enzymatic hydrolysis. It was concluded that the introduction of the collagen phase clearly diminished the mechanical properties of PLA, but the biodegradable property was improved. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1670–1675, 2004
Performance of crystallization analysis fractionation and preparative fractionation on the characterization of γ‐irradiated low‐density polyethylene
Authors: Vilaplana Francisco , Morera‐Escrich Vanesa , del Hierro‐Navarro Pilar , Monrabal Benjamín , Ribes‐Greus Amparo 
Published: September 2004

AbstractThe effects of γ‐radiation on a low‐density polyethylene (LDPE) were investigated by novel techniques, such as crystallization analysis fractionation and preparative fractionation, to analyze and compare their performance with other analytical procedures such as DSC, FTIR, and GPC. The LDPE was thus irradiated with four different doses of γ‐radiation. Different fractions were obtained from these irradiated materials by preparative fractionation, which were characterized by the above‐mentioned analysis techniques. The changes in the morphology and chemical structure of LDPE after the irradiation were analyzed and it was found that both oxidative scission and crosslinking are phenomena related to the exposure of LDPE at high‐energy radiation. Crystallization analysis fractionation and preparative fractionation proved to be suitable techniques to characterize the effects of γ‐radiation on a low‐density polyethylene material. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1803–1814, 2004
Mechanical and thermal properties of poly(lactic acid)/starch blends with dioctyl maleate
Authors: Zhang Jian‐Feng , Sun Xiuzhi 
Published: September 2004

AbstractPoly(lactic acid) (PLA)/starch blends were prepared blending with dioctyl maleate (DOM). DOM acted as a compatibilizer at low concentrations (below 5%), and markedly improved tensile strength of the blend. However, DOM functioned as a plasticizer at concentrations over 5%, significantly enhancing elongation. Compatibilization and plasticization took place simultaneously according to the analysis of, for example, mechanical properties and thermal behavior. With DOM as a polymeric plasticizer, thermal loss in the blends was not significant. Water absorption of PLA/starch blends increased with DOM concentration. DOM leaching in an aqueous environment was inhibited. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1697–1704, 2004
X‐ray photoelectron spectroscopy investigation into thermal degradation and stabilization of polyacrylonitrile fibers
Authors: Wu Gangping , Lu Chunxiang , Wu Xueping , Zhang Shouchun , He Fu , Ling Licheng 
Published: September 2004

AbstractPolyacrylonitrile copolymer fibers have been heated in air to different maximum heat treatment temperatures (MHTT) from 190 to 270°C. The functionalities of C, O, and N in the precursors were determined by X‐ray photoelectron spectroscopy. The intensity of the C1s spectra line 286.8ev, which is identified as C‐O and C = N functionalities, was found to initially increase and suddenly decrease above 230°C. Additionally, the significant broadening of the N1s spectra line was also observed at the same MHTT. It is suggested that some oxygen was incorporated into the six‐member heterocyclic structures that formed by cyclization of nitrile groups and transformed into pyrrole‐type structures by the elimination of carbon monoxide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1705–1709, 2004
Study on molecular chain heterogeneity of linear low‐density polyethylene by cross‐fractionation of temperature rising elution fractionation and successive self‐nucleation/annealing thermal fractionation
Authors: Kong Jie , Fan Xiaodong , Xie Yunchuan , Qiao Wenqiang 
Published: September 2004

AbstractThe molecular chain heterogeneity of commercial linear low‐density polyethylene (LLDPE) was investigated by cross‐fractionation of temperature rising elution fractionation (TREF) and successive self‐nucleation/annealing (SSA) thermal fractionation by use of DSC. The results indicate that the linear relationships between crystallinity or melting temperature and the elution temperature are confirmed by TREF fractions. Intermolecular heterogeneity exists in the original LLDPE, whereas there is less intermolecular heterogeneity in the TREF fractions. After SSA thermal fractionation, the multiple endothermic peaks for both LLDPE and their TREF fractions are mainly attributed to the heterogeneities of ethylene sequence length (ESL) and lamellar thickness. The statistical terms, including weighted mean Lw, arithmetic mean Ln, and broad index Lw/Ln, were introduced to evaluate the heterogeneities of ESL and lamellar thickness of polyethylene. The difference of broadness index indicates that TREF fractions of LLDPE have less inter‐ and intramolecular heterogeneities of both ESL and lamellar thickness than those of the original LLDPE. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1710–1718, 2004
Aqueous polyurethane dispersions derived from polycarbonatediols
Authors: Lee Da‐Kong , Tsai Hong‐Bing , Wang Hsine‐Hsyan , Tsai Ruey‐Shi 
Published: September 2004

AbstractAqueous polyurethane dispersions derived from polycarbonatediols, isophorone diisocyanate, and carboxylic diols including dimethylol propionic acid and dimethylol butyric acid were prepared. The effect of dispersing procedure is investigated by FT IR, GPC, and the tensile film properties. The polyurethane dispersions prepared by a standard procedure exhibit lower molecular weights due to the overhydrolysis of the NCO groups. The polyurethane dispersions prepared by a modified procedure exhibit significantly higher molecular weights due to more effective chain extension, and their cast films exhibit higher tensile strength. The particle size, tensile properties, thermal properties, and dynamic mechanical properties are investigated. The chemical structure of the polycarbonatediols seems to affect the tensile strength. The glass transition temperature of the soft segments, Tg(S), of the polyurethane dispersions can be seem from the DSC and DMA data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1723–1729, 2004
Separation of endocrine disruptors from aqueous solutions by pervaporation: Dioctylphthalate and butylated hydroxytoluene in mineral water
Authors: Higuchi Akon , Yoon Boo Ok , Kaneko Takayuki , Hara Mariko , Maekawa Maya , Nohmi Takashi 
Published: September 2004

AbstractWe examined the existence of endocrine disruptors in mineral water, ultrapure water, and tap water. GC/MS analysis revealed that dioctylphthalate (di‐n‐octylphthalate and di(2‐ethylhexyl)phthalate) in the water was found to be on the order of parts per billion. The dioctylphthalate concentration remained consistent for mineral water of the same brand, regardless of whether it was bottled in a PET bottle or a glass bottle. Therefore, the dioctylphthalate contamination in mineral water originated from the manufacturing line of the mineral water and not as a result of leaching from PET bottles. Butylated hydroxytoluene (BHT), an oxidization prevention agent in plastics, was detected at 2.05 ± 0.1 ppb in the mineral water bottled in glass bottles, but was not detected in the mineral water bottled in PET bottles. BHT contamination in the mineral water in the glass bottles is likely to have originated from the cap of the glass bottles, as the caps were sealed with polyethylene. We further investigated the feasibility of separating dioctylphthalate and BHT from the mineral water by pervaporation using hydrophobic polydimethylsiloxane membranes. We found that trace amounts (on the order of parts per billion) of organic chemicals such as dioctylphthalate and BHT in aqueous solutions can be removed and concentrated by the pervaporation using polydimethylsiloxane membranes. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1737–1742, 2004
Preparation and properties of waterborne poly(urethane urea)s for adhesives: The effects of the 2,2‐bis(hydroxylmethyl)propionic acid content on the properties
Authors: Kwak Yong Sil , Kim Eun Young , Ha Yoo Byung , Kim Han Do 
Published: September 2004

AbstractA series of waterborne poly(urethane urea)s (WBPUs) containing various concentrations (8.3–15.5 mol %) of 2,2‐bis(hydroxylmethyl)propionic acid (DMPA) were prepared from isophorone diisocyanate, poly(tetramethylene adipate) glycol, DMPA, ethylenediamine, and triethylamine. The length of the hard segment with the DMPA content was varied from 18.7 to 22.6 wt % at a fixed soft‐segment length (2000 g/mol). The effect of the DMPA content on the colloidal properties of WBPU dispersions, the hydrogen‐bonding index, water swelling, dynamic mechanical thermal properties, and mechanical properties of WBPU films, and the adhesive strengths of substrates such as chloroprene rubber (CR)/CR, CR/polyurethane foam, CR/ethylene vinyl acetate foam, and thermoplastic olefin sheet/polypropylene foam were investigated. Stable aqueous dispersions of WBPU were obtained when the DMPA concentration was greater than 10 mol %. As the DMPA content increased, the particle size of the WBPU dispersion decreased, but the viscosity of the WBPU dispersion increased. The hydrogen‐bonding fraction, water swelling, dynamic storage modulus and relaxation temperature, and tensile strength of the films increased with increasing DMPA content. According to an adhesion test, the substrates adhering to WBPU with greater than 10 mol % DMPA tore at about 8.0 kgf/cm2 instead of breaking the adhered region. These results suggested that the WBPUs prepared in this study could have potential for adhesive use. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1743–1751, 2004
Simple chemical polymerization method for the deposition of a conducting polyaniline on the surface of acrylonitrile–butadiene–styrene. II. Treatment in organic free solvent
Authors: Matveeva E. , Carrascosa R. Enguix , Martínez Palomino R. J. , Parkhutik V. 
Published: September 2004

AbstractWe developed a simple method for the deposition of a uniform layer of polyaniline (PANI) on the surface of acrylonitrile–butadiene–styrene (ABS). The method consisted of two steps: the soaking of ABS samples in a water‐based aniline solution stabilized by surfactants followed by the oxidative polymerization of the adsorbed and absorbed monomer. The three types of surfactants (molecular N,N‐dimethyl‐octalamine‐N‐oxide, anionic sodium dodecyl sulfate, and cationic hexadecyl trimethyl ammonium bromide) were used to prepare and stabilize the aniline emulsions in water. After treatment, the ABS surface was completely covered by PANI (as seen with scanning electron microscopy). The surface conductivity after PANI coating reached values between 10−3 and 10−4 S/□ in the best developed conditions. The chemical nature of the surfactant affected the particular setting of the aniline/surfactant emulsion preparation (time of ultrasonification = 15–30 min), its optimal concentration (2–10 wt % aniline and 0.1–0.2M surfactant), and other parameters of treatment, such as time (10 s to 20 min) and temperature (20–60°C) of soaking. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1752–1758, 2004
Viscosity/molecular‐weight relationship for γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane)s
Authors: Feng Shengyu , Zhang Jie , Wang Dake , Wu Mingyan , Yu Zhaotan 
Published: September 2004

AbstractA series of γ‐(2,3‐dihydroxypropoxy)propyl‐terminated poly(dimethylsiloxane) (DHT‐PDMS) samples with different molecular weights were prepared through the acid‐catalyzed equilibrium copolymerization of octamethylcyclotetrasiloxane and 1,3‐bis[γ‐(2,3‐dihydroxypropoxy)propyl]tetramethyldisiloxane. The intrinsic viscosity in toluene ([η]toluene) and the number‐average molecular weight (Mn) were determined with an Ubbelohde viscometer and 1H‐NMR spectra, respectively. In this way, the relationship between [η]toluene and Mn was established. For 2.0 × 104 < Mn < 4.0 × 104, [η]toluene,25°C was 1.874Mn 0.323. The solution behavior of DHT‐PDMS was also investigated. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1759–1762, 2004
Use of a sodium ionomer as a compatibilizer in polypropylene/high‐barrier ethylene–vinyl alcohol copolymer blends: The processability of the blends and their physical properties
Authors: Abad M. J. , Ares A. , Barral L. , Cano J. , Díez F. J. , García‐Garabal S. , López J. , Ramírez C. 
Published: September 2004

AbstractThe effect of a sodium ionomer (ion.Na+) on the compatibility of polypropylene (PP)/high‐barrier ethylene–vinyl alcohol copolymer (EVOH) blends was studied in terms of the thermal, mechanical, and optical properties and morphology. The rheological behavior, tensile tests, and morphology of the binary blends showed that the miscibility of EVOH with PP was very poor. The miscibility of the polymers improved with the ionomer addition. In general, the ion.Na+ concentration did not alter the thermal behavior of the blends, but it did improve the ductility of the injection‐molded specimens. Scanning electron micrographs displayed better adhesion between the PP and EVOH phases in the samples with the ionomer. The mechanical improvement was better in the film samples than in the injection‐molded samples. A 90/10 (w/w) PP/EVOH film with 5% ion.Na+ and an 80/20 (w/w) PP/EVOH film with 10% ion.Na+ presented better global properties than the other blends studied. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1763–1770, 2004
Synthesis and analytical application of a chelating resin based on a crosslinked styrene/maleic acid copolymer for the extraction of trace‐metal ions
Authors: Roy P. K. , Rawat A. S. , Choudhary V. , Rai P. K. 
Published: September 2004

AbstractA new chelating polymer sorbent was synthesized through the copolymerization of styrene and maleic anhydride in the presence of divinyl benzene as the crosslinking agent, followed by hydrolysis. This polymeric resin, bearing O donor groups, had the advantage of being stable in basic and saline media, unlike its linear analogue. This newly developed chelating matrix has a high resin capacity for metal ions such as Cr, Fe, Ni, Cu, and Pb. Various physicochemical parameters, such as the pH, volume, and flow rate, and the interference effect on metal uptake were studied. The sorption capacities of the crosslinked resin for Cr(III), Fe(III), Ni(II), Cu(II), and Pb(II) were 10.2, 14.3, 14.2, 15.4, and 8.8 mg/g, respectively. A high recovery of 98% was obtained for all the metal ions with 2N HCl as the eluting agent. The chelating resin was characterized by swelling studies, Fourier transform infrared, elemental analysis, X‐ray studies, and thermal analysis. The Langmuir and Freundlich adsorption isotherms were used to validate the metal‐uptake data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1771–1779, 2004
Mechanical and thermal properties of ceramic‐modified poly(amide imide)
Authors: Park Young‐Wook , Lee Dong‐Sung 
Published: September 2004

AbstractPoly(amide imide)–epoxysilane (coupling agent) composites were reacted with silica, a condensation product of tetraethylorthosilicate (TEOS), by a sol–gel process and were then cast into films. After this procedure, the chemical characteristics and mechanical and thermal properties were measured. Fourier transform infrared showed that silica existed in the poly(amide imide) matrix. When a proper amount of silica was added to the poly(amide imide) matrix, the tensile strength, elongation, and toughness increased greatly. A poly(amide imide)/30 wt % epoxysilane composite with 20 wt % TEOS had the best mechanical properties. Thermogravimetric analysis under nitrogen and oxygen atmospheres indicated that the char contents increased with the amount of silica. The glass‐transition temperatures of the poly(amide imide)–silica nanocomposites were observed around 170–180°C with differential scanning calorimetry. This approach may be a new method for the low‐temperature thermal curing of poly(amide imide). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1780–1788, 2004
Synthesis and characterization of diblock, triblock, and multiblock copolymers containing poly(3‐hydroxy butyrate) units
Authors: Arslan Hülya , Menteş Ayfer , Hazer Baki 
Published: September 2004

AbstractA poly[(R,S)‐3‐hydroxybutyrate] macroinitiator (PHB‐MI) was obtained through the condensation reaction of poly[(R,S)‐3‐hydroxybutyrate] (PHB) oligomers containing dihydroxyl end functionalities with 4,4′‐azobis(4‐cyanopentanoyl chloride). The PHB‐MI obtained in this way had hydroxyl groups at two end of the polymer chain and an internal azo group. The synthesis of ABA‐type PHB‐b‐PMMA block copolymers [where A is poly(methyl methacrylate) (PMMA) and B is PHB] via PHB‐MI was accomplished in two steps. First, multiblock active copolymers with azo groups (PMMA‐PHB‐MI) were prepared through the redox free‐radical polymerization of methyl methacrylate (MMA) with a PHB‐MI/Ce(IV) redox system in aqueous nitric acid at 40°C. Second, PMMA‐PHB‐MI was used in the thermal polymerization of MMA at 60°C to obtain PHB‐b‐PMMA. When styrene (S) was used instead of MMA in the second step, ABCBA‐type PMMA‐b‐PHB‐b‐PS multiblock copolymers [where C is polystyrene (PS)] were obtained. In addition, the direct thermal polymerization of the monomers (MMA or S) via PHB‐MI provided AB‐type diblocks copolymers with MMA and BCB‐type triblock copolymers with S. The macroinitiators and block copolymers were characterized with ultraviolet–visible spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography, cryoscopic measurements, and thermogravimetric analysis. The increases in the intrinsic viscosity and fractional precipitation confirmed that a block copolymer had been obtained. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1789–1796, 2004
Poly(oxyethylene)diamine‐derived hydrophilic copolymers for emulsifying diglycidylether of bisphenol‐A
Authors: Lin Jiang‐Jen , Chen Shi‐Min , Hu Shang‐Siou 
Published: September 2004

AbstractA series of reactive surfactants were synthesized by the reaction of hydrophilic poly(oxyethylene)diamines of 2000–6000 g/mol molecular weight and diglycidylether of bisphenol‐A resin. The synthesized surfactants consisted of multiple functionalities including tertiary amines, hydrophobic alkylphenoxys, and reactive oxirane groups. After treatment with hydrochloric acid, the surfactants consisted of two different hydrophilic groups: cationic quaternary ammonium salts and nonionic oxyethylene segments. By prudent selection of the proper hydrophile–lipophile balance, the surfactant can be highly effective for solubilizing the epoxy resin in water to form a stable emulsion at a fine particle size of 350 nm. Another advantage is that the surfactant may participate in a curing process through the built‐in oxirane reaction and become a nonextractable component in polymer matrix. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1797–1802, 2004
Computer simulation and comparative study on the pervaporation separation characteristics of sodium alginate and its blend membranes with poly(vinyl alcohol) to separate aqueous mixtures of 1,4‐dioxane or tetrahydrofuran
Authors: Aminabhavi Tejraj M. , Vijaya Kumar Naidu B. , Sridhar S. 
Published: September 2004

AbstractA comparative study on the pervaporation separation has been attempted for water + 1,4‐dioxane and water + tetrahydrofuran mixtures using sodium alginate and blend membranes of sodium alginate with 5, 10, and 20 mass % of poly(vinyl alcohol). Pure sodium alginate membrane has a selectivity of 111 to water at 0.35‐mol fraction of water in the feed mixture containing 1,4‐dioxane while for water + tetrahydrofuran mixture, the membrane selectivity to water was 291 at 0.31‐mol fraction of water in the feed mixture. Pervaporation results have been discussed using the solution–diffusion principles. Arrhenius activation parameters for diffusion and permeation have been computed from the temperature‐dependent pervaporation results. Furthermore, experimental results have been analyzed using the complete mixing and plug flow models to compute membrane area as well as design parameters that are useful in scale‐up operations. The plug flow model is more appropriate than the complete mixing model to analyze the pervaporation results. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1827–1840, 2004