bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of high‐molecular‐weight poly(vinyl alcohol) with high yield by solution polymerization of vinyl acetate in methanol using 4,4′‐azobis(4‐cyanovaleric acid)
Authors: Lyoo Won S. , Song Du H. , Lee Won C. , Han Sung S. , Noh Seok K. 
Published: September 2006

AbstractVinyl acetate (VAc) was solution‐polymerized at 40°C and 50°C using 4,4′‐azobis(4‐cyanovaleric acid) (ACVA) as an initiator and methanol as a solvent, and effects of polymerization temperature and initiator concentration were investigated in terms of conversion of VAc into poly (vinyl acetate) (PVAc), degree of branching (DB) for acetyl group of PVAc, and molecular weights of PVAc and resulting poly(vinyl alcohol) (PVA) obtained by saponifying with sodium hydroxide. Slower polymerization rate by adopting ACVA and lower viscosity by methanol proved to be efficient in obtaining linear high‐molecular‐weight (HMW) PVAc with high conversion and HMW PVA. PVA having maximum number–average degree of polymerization (Pn) of 4300 could be prepared by the saponification of PVAc having maximum Pn of 7900 polymerized using ACVA concentration of 2 × 10−5 mol/mol of VAc at 40°C. Moreover, low DB of below 1 could be obtained in ACVA system, nevertheless of general polymerization temperatures of 40°C and 50°C. This suggests an easy way for producing HMW PVA with high yield by conventional solution polymerization without using special methods such as low‐temperature cooling or irradiation. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 4831–4834, 2006
X‐ray photoelectron, infrared, and Raman spectroscopy studies of novel submicrometric poly[(methacrylato)aluminum(III)]
Authors: Vilchis‐Nestor Alfredo R. , Sánchez‐Mendieta Victor , Ureña‐Nuñez Fernando , López‐Castañares Rafael , Ascencio Jorge A. 
Published: September 2006

AbstractPoly[(methacrylato)aluminum(III)] was prepared by applying γ‐radiation to the corresponding aluminum(III) methacrylate monomer. Scanning electron microscopy images show pellets of ∼ 500 nm for the aluminum(III) methacrylate monomer, and submicrometric fibers‐made granules for the aluminum‐containing polymers. X‐ray photoelectron spectroscopy measurements reveal two peaks in the Al 2p core‐level spectra of the monomer and of the poly[(methacrylato)aluminum(III)], which means that two different coordination modes for the Al(III) ions might be present in these compounds. Infrared and Raman spectroscopy studies confirmed that the structure for this novel coordination polymer consists of hexa‐coordinated Al(III) ions linked by the carboxylate groups of methacrylate ligands, along with hydroxyl groups and coordinated water, in a combination of monodentate and bridging bidentate coordination modes. Hence, combination of spectroscopic methods is a helpful tool to get valuable information on the structure of nonmacrocrystalline coordination polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5212–5223, 2006
Effect of microphase‐separation promoters on the shape‐memory behavior of polyurethane
Authors: Chen Shaojun , Cao Qi , Jing Bo , Cai Yuanli , Liu Pengsheng , Hu Jinlian 
Published: September 2006

AbstractA series of segmented polyurethanes (PUs) with novel thermosensitive shape‐memory behavior were synthesized via the in situ addition of a small amount of 1‐octadecanol (ODO) to a PU system. For comparison, liquid paraffin (LP) modified PUs were also synthesized. The effects of a small amount of ODO or LP on the PU suprastructure and the thermosensitive shape‐memory properties were studied with X‐ray diffraction, differential scanning calorimetry, dynamic mechanical analysis, and shape‐memory studies. The results indicated that the in situ addition of a small amount of ODO (e.g., 0.3 wt %) remarkably promoted microphase separation, facilitating the ordered packing of soft segments and the formation of perfect hard‐segment domains and thus significantly improving the shape‐memory properties. In contrast, LP had less significant influence on the shape‐memory behavior because of the macrophase separation of these nonpolar alkyl chains from the PU system. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5224–5231, 2006
Preparation and characterization of biodegradable foams from calcium carbonate reinforced poly(propylene carbonate) composites
Authors: Jiao J. , Xiao M. , Shu D. , Li L. , Meng Y. Z. 
Published: September 2006

AbstractBiodegradable foams were successfully prepared from calcium carbonate reinforced poly(propylene carbonate) (PPC/CaCO3) composites using chemical foaming agents. The incorporation of inexpensive CaCO3 into PPC provided a practical way to produce completely biodegradable and cost‐competitive composite foams with densities ranging from 0.05 to 0.93 g/cm3. The effects of foaming temperature, foaming time and CaCO3 content on the fraction void, cell structure and compression property of the composite foams were investigated. We found that the fraction void was strongly dependent on the foaming conditions. Morphological examination of PPC/CaCO3 composite foams revealed that the average cell size increased with increasing both the foaming temperature and the foaming time, whereas the cell density decreased with these increases. Nevertheless, the CaCO3 content showed opposite changing tendency for the average cell size and the cell density because of the heterogeneous nucleation. Finally the introduction of CaCO3 enhanced the compressive strength of the composite foams dramatically, which was associated with well‐developed cell morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:5240–5247, 2006
Mechanical and morphological properties of recycled high‐density polyethylene, filled with calcium carbonate and fly ash
Authors: Atikler U. , Basalp D. , Tihminlioğlu F. 
Published: September 2006

AbstractIn this study, mechanical and morphological properties of composites made up of recycled high‐density polyethylene (HDPE) filled with calcium carbonate and fly ash (FA) were studied. Interfacial interactions were modified to improve the filler compatibility and mechanical properties of the composites by surface treatment of the FA filler with 3‐amino propyl triethoxy silane. The composites were prepared by using a Thermo Haake Rheomixer. Effect of filler loading and treatment of FA with silane coupling agent on mechanical and morphological properties were investigated and it was found that silane treatment indicated significant improvements on the mechanical properties of the HDPE‐FA composites. The improvement with silane treatment of FA was also confirmed by applying the Pukanszky model. Scanning electron microscopy on the fracture surface of composites had given direct evidence of better interfacial adhesion via silane treatment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4460–4467, 2006
Grafting of N‐carbamyl maleamic acid onto a styrene–butadiene–styrene copolymer
Authors: Lassalle V. L. , Failla M. D. , Vallés E. M. 
Published: September 2006

AbstractA styrene–butadiene–styrene block copolymer (SBS) was functionalized with N‐carbamyl maleamic acid (NCMA) using two peroxide initiators with the aim of grafting polar groups onto the molecular chains of the polymer. The influence of the concentration of benzoyl peroxide (BPO) and 2,5‐dimethyl, 2,5‐diterbuthylperoxihexane (DBPH) was studied. The concentration of peroxy groups ranged between 0.75 and 6 × 10−4 mol % while the concentration of NCMA was constant at 1 wt %. The reaction temperature was chosen according to the type of peroxide employed, being 140°C for BPO and 190°C for DBPH. FTIR spectra confirmed that NCMA was grafted onto the SBS macromolecules. It was found that the highest grafting level was achieved at a concentration of peroxy groups of about 3 × 10−4 mol %. Contact angle measurements were used to characterize the surface of the SBS and modified polymers. The contact angle of water drops decreased with the amount of NCMA grafted from 95°, the one corresponding to the SBS, to about 73°. T‐peel strength of polymer/polyurethane adhesive/polymer joints made with the modified polymers was larger than those prepared with the original SBS. The peel strength of SBS modified with 1.5 and 3 × 10−4 mol % of peroxy groups from BPO were five times larger than that of the original SBS. The materials modified using BPO showed peel strengths higher than the ones obtained with DBPH. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4468–4477, 2006
Structure of P(VDF‐TrFE) (80/20) copolymers under electron irradiation and recrystallization
Authors: Li Weiping , Jiang Limin , Zhu Yuejin , Wang Jun 
Published: September 2006

AbstractThe structural changes of irradiated and recrystallized copolymers of vinylidene fluoride and trifluoroethylene [P(VDF‐TrFE)] (80/20) copolymers have been investigated through IR spectra, X‐ray, and DSC. It is found that recrystallization has a reverse effect on irradiated P(VDF‐TrFE) copolymers, by which the irradiated samples are turned back to original nonirradiated state partially. During recrystallization, trans‐gauche sequences are replaced by all‐trans conformation gradually and the irradiated P(VDF‐TrFE) (80/20) copolymers change from nonpolar phase to polar one. The average crystallite size of polar phase is larger than that in irradiated samples, and the difference between recrystallized and irradiated samples reduces gradually with irradiation dosage. The CC and conjugated CC bonds are also found in the recrystallized‐irradiated P(VDF‐TrFE) (80/20) due to rearrangement of broken bonds. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4258–4263, 2006
Influence of 1,2‐unit contents on retraction behaviors of SBR vulcanizates
Authors: Choi Sung‐Seen , Cho Gyunggoo 
Published: September 2006

AbstractStyrene‐butadiene rubber (SBR) has four different repeat units of styrene, cis‐1,4‐, trans‐1,4‐, and 1,2‐uints. Influence of the 1,2‐unit content on the retraction behaviors of SBR vulcanizates reinforced with silica or carbon black was studied. The retraction behaviors were compared in terms of the filler systems and the microstructures of SBR. The silica‐filled vulcanizates containing a coupling agent showed nearly the same retraction behaviors as the carbon black‐filled ones, but the silica‐filled vulcanizates without a coupling agent were recovered slower than the carbon black‐filled ones. The vulcanizates with lower 1,2‐unit content started to recover at lower temperature than that with higher 1,2‐unit content. The recovery rate increased with increase of the 1,2‐unit content of SBR. The experimental results were explained with the polymer‐filler interactions, filler dispersion, glass transition temperature, and modulus. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4707–4711, 2006
A constitutive law for poly(butylene terephthalate) nanofibers mats
Authors: De Vita R. , Leo D. J. , Woo K. D. , Nah C. 
Published: September 2006

AbstractA three‐dimensional structural constitutive equation is proposed to describe the mechanical properties of poly(butylene terephthalate) nanofibers mats. The model is formulated under the assumption that the mechanical response of the fibrous mat is determined by the individual fibers. The inelasticity, which has been observed when subjecting the fibrous mat to tensile tests, is assumed to be due to the gradual breakage of linear elastic fibers. The constitutive relation also takes the material anisotropy associated with the fibers' architecture into account. Uniaxial experimental data were used to assess the proposed model. The results demonstrate that the model is well suited to reproduce the typical tensile behavior of the fibrous mat. In agreement with the empirical observations, the model predicts that almost all the fibers fail when the poly(butylene terephthalate) fibrous mat sample breaks. Nevertheless, multiaxial stress–strain data and quantification of the fibers' orientation are required to completely validate the constitutive law. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5280–5283, 2006
Characterization of (PEO)LiClO4‐Li1.3Al0.3Ti1.7(PO4)3 composite polymer electrolytes with different molecular weights of PEO
Authors: Wang Yan‐Jie , Pan Yi , Wang Li , Pang Ming‐Jie , Chen Linshen 
Published: September 2006

AbstractA group of polyethylene oxide (PEO)LiClO4‐Li1.3Al0.3Ti1.7(PO4)3 composite polymer electrolyte (CPE) films was prepared by the solution‐cast method. In each film, EO/Li = 8 and the Li1.3Al0.3Ti1.7(PO4)3 content of 15 wt % were fixed, but the number averaged molecular weight of PEO (Mn) was altered from 5 to 7 × 104 to 106, 2.2–2.7 × 106, 3–4 × 106, 4–5 × 106, and 5.5–6 × 106, respectively. Several techniques including X‐ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and electrical impedance spectroscopy (EIS) were used to characterize the CPE films. LiClO4 was found to have a strong tendency to complex with PEO, but Li1.3Al0.3Ti1.7(PO4)3 was rather dispersed in PEO matrix. DSC analysis revealed that the amorphous phase was dominant in the CPE films although the PEOs before‐use was considerably crystalline. SEM study showed smooth and homogeneous morphologies of the films with low molecular weight PEO and a dual phase characteristic for those with high molecular weight PEO. EIS results indicated that the CPE films are all ionic conductor and the conducting behavior obeys Vogel‐Tamman‐Fulcher (VTF) equation. The parameters in VTF equation were obtained and discussed by taking into considerations PEO molecular weights and crystallinities of the CPE films. Of all the films, the one with PEO with the smallest Mn = 5–7 × 104 had the maximum conductivity, i.e., 1.590 × 10−5 S cm−1 at room temperature and 1.886 × 10−3 S cm−1 at 373 K. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4269–4275, 2006
Surface hydrolysis of postconsumer polyethylene terephthalate to produce adsorbents for cationic contaminants
Authors: Rosmaninho Marcelo G. , Jardim Erika , Moura Flávia C. C. , Ferreira Gilmara L. , Thom Viviani , Yoshida Maria I. , Araujo Maria H. , Lago Rochel M. 
Published: September 2006

AbstractIn this work, the surface hydrolysis of postconsumer polyethylene terephthalate (PET) was used to produce an ion exchange material to adsorb cationic contaminants from water. The PET surface hydrolyses were carried out in neutral, alkaline, and acid media (NaOH or HNO3 at 7, 10, and 15 mol L−1) under reflux producing surface carboxylic acid sites (COOH) characterized by ATR‐IR, pyridine adsorption, titration, TG, and DSC analyses. Acid hydrolysis produced high concentrations of COOH (up to 0.5 mmol g−1PET), whereas no significant concentration of carboxylic acid sites was obtained by neutral and alkaline hydrolysis. SEM analyses suggest that the acid sites are likely located at the cracks and defects produced on the PET surface by acid hydrolysis. Neutral or alkaline hydrolysis produced a very regular and smooth PET surface with very low acid site concentrations. The adsorption isotherms of Cd+2 as a model of heavy metal and the dye methylene blue as a model of large organic cationic molecules showed high adsorption capacities for the HNO3‐hydrolyzed PET, whereas no adsorption takes place on the neutral‐ or alkaline‐hydrolyzed polymer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5284–5291, 2006
Dynamic mechanical and rheological behavior of fluoroelastomer‐organoclay nanocomposites obtained from different preparation methods
Authors: Valsecchi R. , Viganò M. , Levi M. , Turri S. 
Published: September 2006

AbstractA comparison among different preparation methods of fluoropolymer/clay nanocomposites based on a fluoroelastomeric matrix (Tecnoflon® P959) and organomodified montmorillonite clay (Cloisite®20A) is reported. While melt blending leads to intercalated structures, the X‐ray diffraction patterns of solution blended nanocomposite suggest a better delamination of the clay platelets within the fluoropolymeric matrix (no diffraction peaks) if the solvent evaporation step is carried out very slowly (72 h) at ambient pressure and moderate temperature. For the solution blended‐slow evaporation nanocomposite, dynamic mechanical analysis and dynamic rheological measurements show a strong increase in G′, a lower damping peak at Tg, and a pseudosolid like behavior in the terminal flow region, suggesting a likely exfoliation of the organomodified clay in the fluoroelastomeric matrix. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4484–4487, 2006
Polymerization of monomers initiated by silyl centers in SiO deposits prepared by pulsed laser ablation
Authors: Dřínek Vladislav , Vacek Karel , Yuzhakov Gleb , Brus Jiří 
Published: September 2006

AbstractDeposits from silicon monoxide prepared by pulsed laser ablation were allowed to react with acrylic and vinyl monomers—styrene, methyl methacrylate and 1,2 ethylene glycol dimethacrylate. It was revealed by means of FTIR, electron paramagnetic resonance (EPR), and NMR spectroscopies that silyl Si· reacts with monomer molecules and initiates the consecutive polymerization. Crosslinking is proved by the occurrence of bending δ(CH2) absorption peak at about 750 cm−1 in FTIR spectra. Because of very low concentration of the propagating radical for styrene we used a radical scavenger N‐phenyl‐t‐butylnitrone for trapping. The measured EPR parameters were compared with the calculated ones. In case of styrene, NMR analysis manifested the presence of SiC bonds in SiCxOy (x + y = 2) units, which can be taken as direct evidence of the reaction between silyl centers and monomer molecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4488–4492, 2006
Effect of partial replacement of di(2‐ethyl hexyl)phthalate, by a polymeric plasticizer, on the permeability and leaching properties of poly(vinyl chloride)
Authors: Sunny M. C. , Ramesh P. , George K. E. 
Published: September 2006

AbstractAcrylonitrile butadiene rubber (NBR) was used as a polymeric plasticizer in poly(vinyl chloride) (PVC) for the partial replacement of di(2‐ethyl hexyl)phthalate (DEHP). The effect of this partial replacement on DEHP leaching from the PVC was evaluated at 10, 25, and 40°C. The study shows that the incorporation of NBR reduces the rate of DEHP leaching, the reduction being prominent at lower temperatures. Gas permeability of the NBR‐modified samples was also evaluated at the above temperatures using oxygen and carbon dioxide. A reduction in gas permeability is observed in NBR‐modified samples compared to the PVC plasticized with DEHP alone particularly in the case of carbon dioxide. Water vapor transmission rates of the NBR‐modified samples are higher than that of the control sample. The NBR‐modified PVC sample was found to be noncytotoxic in the in vitro cytotoxic evaluation both by direct contact and test on extract methods. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4720–4727, 2006
Effect of Quasi‐nanometer zirconium carbide on the physical characterization of zirconium carbide/polyurethane composite films irradiated under ultraviolet light
Authors: Tasi Hui‐An , Suen Maw‐Cherng , Chen Cheng‐Chi 
Published: September 2006

AbstractWe used quasi‐nanometer zirconium carbide (ZrC) and a polyurethane (PU) resin under roller pressure to form a composite film and found that the tensile strength at break, elongation at break, and modulus gradually decreased with increasing ultraviolet (UV)‐irradiation time for films of both PU and the PU/ZrC composite. However, this phenomenon was significantly higher for the PU film than for the ZrC/PU composite film. The construction of the PU film changed after UV irradiation, but that of the PU/ZrC composite film was almost unchanged. The degradation of PU molecules occurred in the absence of ZrC particles after irradiation with UV light but almost did not occur in the presence of ZrC particles. This was confirmed with Fourier transform infrared spectroscopy and gel permeation chromatography analyses. It was suggested that polymer radicals which formed through the photooxidation of UV irradiation and free radicals which formed through the photoreduction of nanometer ZrC/UV irradiation interacted to form a dead polymer to stop the degradation; simultaneously, the chemical bonding between polymer molecules could be re‐formed from free radicals created by photooxidation and photoreduction and thus reduce the mobility of PU molecules, thereby raising the glass‐transition and melting temperatures of the soft segment. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4842–4849, 2006
Retention of activity of urease immobilized on grafted polymer films
Authors: Yamada Kazunori , Iizawa Yoshinori , Yamada Jun‐ichi , Hirata Mitsuo 
Published: September 2006

AbstractExpanded poly(tetrafluoroethylene) (ePTFE) films grafted with 2‐hydroxyethyl methacrylate (HEMA) and 2‐hydroxyethyl acrylate (HEA) were applied to a polymer support for urease immobilization. The HEMA‐ and HEA‐grafted ePTFE (ePTFE‐g‐PHEMA and ePTFE‐g‐PHEA) films prepared by the combined use of the plasma treatment and photografting possessed high water‐absorptivities. Imidazole groups were introduced to grafted PHEMA and PHEA chains with 1,1′‐carbonyldiimidazole (CDI) in acetonitrile. The activity of urease covalently immobilized to the ePTFE‐g‐PHEMA and ePTFE‐g‐PHEA films in a pH 7.0 buffer at 4°C had the maximum value at the optimum pH value of 7.5 for native urease. Urease immobilized on the ePTFE‐g‐PHEMA films with the extent of CDI bonding of about 20% had the maximum activity, and the repeatedly measured activity was kept almost constant. The relative activity of immobilized urease stayed almost constant in the range of the immobilized amounts between 10 and 30 mg/g for both grafted ePTFE films, and decreased at higher immobilized amounts because of the crowding of immobilized urease molecules in the grafted layers. The relative activity of immobilized urease had the maximum values at the grafted amounts of 1.2 and 1.7 mmol/g for the ePTFE‐g‐PHEMA and ePTFE‐g‐PHEA films, respectively, and the further increase in the grafted amount resulted in the decrease in the relative activity. The optimum temperature of the activity for immobilized urease was shifted from 30 to 50°C for native urease by the covalent immobilization on both grafted ePTFE films and immobilized urease was repeatedly usable without a considerable decrease in the activity in the regions of the pH 6.0–9.0 and 10–60°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4886–4896, 2006
Synthesis and characterization of hydrophilic nanocomposite coating on glass substrate
Authors: Rahimi Azam , Gharazi Salimeh , Ershad‐Langroudi Amir , Ghasemi Diba 
Published: September 2006

AbstractHydrophilic coatings based on 3‐glicidoxy propyl trimethoxy silane (GPTMS) and polyethylene glycol (PEG) were prepared with the incorporation of tetramethoxysilane (TMOS) and silica nanoparticle colloidal suspension by a sol–gel process. Characterization of the coatings has been performed by Fourier Transform Infrared (FTIR) and Attenuated Total Reflectance Infrared (ATR‐IR) techniques. Morphological properties were characterized by Scanning Electron Microscopy (SEM). The distribution of Si atoms in the hybrid system was obtained by Si mapping. The particle size in sol solution of the coating was measured by light scattering analyzer. Optical properties were characterized by using UV–vis spectrophotometer. The hydrophilicity of the coating was determined by contact angle measurements, and also the results have been confirmed by surface energy and water uptake investigations. The obtained results indicate that the surfactants affected the contact angles remarkably but did not change the transparency. It has been found that applying silica nano particles leads to coatings with different properties than those using TMOS, while siloxane contents were the same in these two set of coatings. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5322–5329, 2006