bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal degradation of high‐temperature fluorinated polyimide and its carbon fiber composite
Authors: Adamczak Andrea D. , Spriggs Adam A. , Fitch Danielle M. , Awad Walid , Wilkie Charles A. , Grunlan Jaime C. 
Published: October 2009

AbstractHigh‐temperature polymers are being used for a broad range of applications, such as composite matrices for structural applications (e.g., high speed aircraft). Polyimides are a special class of polymers that meet the thermal and oxidative stability requirements for high temperature composite aerospace applications. A weight loss study was performed on a fluorinated polyimide resin and its carbon fiber composite in an effort to determine its thermal stability and degradation mechanisms. Experiments were conducted using a preheated oven and thermogravimetric analysis to obtain the weight loss. Regardless of the method used, the resin and composite exhibited excellent thermal stability (less than 1% weight loss) below 430°C, regardless of 2–20 min of exposure. After 20 min of exposure at 510°C, the composite remained relatively stable with only 5.3% weight loss using the oven technique, whereas the neat polyimide sustained 12.6%. When degradation occurred, it was found to be the result of thermolysis and oxidation (to a lesser extent). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(lactic acid) and zeolite composites prepared by melt processing: Morphological and physical–mechanical properties
Authors: Yuzay Isinay E. , Auras Rafael , Selke Susan 
Published: October 2009

AbstractPoly(lactic acid), PLA, composites containing 0, 1, 3, and 5 wt % zeolite type 4A were prepared using extrusion/injection compounding techniques. Morphological characterizations were carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Physical properties were evaluated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) and mechanical properties by standard tensile testing. The morphological studies showed a homogenous dispersion of zeolite particles within the PLA matrix. As the fracture stress propagated, zeolite particles remained embedded into the matrix, indicating the existence of good interfacial adhesion between zeolite particles and the PLA matrix. The improvement in the interfacial adhesion was also confirmed by applying Nicolais‐Narkis and Pukanszky models. The percent crystallinity of the PLA and the temperature‐ dependant elastic and viscous modulus of the composite increased with the proportion of zeolites. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of mixed solvents and PVDF types on performances of PVDF microporous membranes
Authors: Li Qian , Xu Zhen‐Liang , Yu Li‐Yun 
Published: October 2009

AbstractPolyvinylidene fluoride (PVDF) microporous flat membranes were cast with different kinds of PVDFs and four mixed solvents [trimethyl phosphate (TMP)–N,N‐dimethylacetamide (DMAc), triethyl phosphate (TEP)–DMAc, tricresyl phosphate (TCP)–DMAc, and tri‐n‐butyl phosphate (TBP)–DMAc]. The effects of different commercial PVDFs (Solef® 1015, FR 904, Kynar 761, Kynar 741, Kynar 2801) on membrane morphologies and membrane performances of PVDF/TEP–DMAc/PEG200 system were investigated. The membrane morphologies were examined by scanning electron microscopy (SEM). The membrane performances in terms of pure water flux, rejection, porosity, and mean pore radius were measured. The membrane had the high flux of 143.0 ± 0.9 L m−2 h−1 when the content of TMP in the TMP–DMAc mixed solvent reached 60 wt %, which was 2.89 times that of the membrane cast with DMAc as single solvent and was 3.36 times that of the membrane cast with TMP as single solvent. Using mixed solvent with different solvent solubility parameters, different morphologies of PVDF microporous membranes were obtained. TMP–DMAc mixed solvent and TEP–DMAc mixed solvent indicated the stronger solvent power to PVDF due to the lower solubility parameter difference of 1.45 MPa1/2 and the prepared membranes showed the faster precipitation rate and the higher flux. The less macrovoids of the membrane prepared with TEP (60 wt %)–DMAc (40 wt %) as mixed solvent contributed to the higher elongation ratio of 96.61% ± 0.41%. Therefore, using TEP(60 wt %)–DMAc (40 wt %) as mixed solvent, the casting solution had the better solvent power to PVDF, and the membrane possessed the excellent mechanical property. The microporous membranes prepared from casting solutions with different commercial PVDFs exhibited similar morphology, but the water flux increased with the increment of polymer solution viscosity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Epoxy acrylate UV/PU dual‐cured wood coatings
Authors: Chang Chia‐Wei , Lu Kun‐Tsung 
Published: October 2009

AbstractFor improving the finishing performances of complicated three‐dimensional coated wood products (e.g., furniture) with some shadow zones in the absence of ultraviolet (UV) light, resulting in incomplete curing of UV coatings, the aim of this study was to investigate the characteristics and effects of curing process on the properties of epoxy acrylate UV/PU dual‐cured resin for wood coatings when compared with traditional UV and polyurethane (PU) coatings. The epoxy acrylate oligomer was synthesized for providing a double bond of acryloyl group and a secondary hydroxyl group. The UV/PU dual‐cured coating was formulated with epoxy acrylate resin/tripropylene glycol diacrylate (TPGDA) monomer by the weight ratio of 80/20, 3% dosage of benzil dimethyl ketal as a photoinitiator, and the NCO/OH mole ratio of 1.0. The aromatic polymeric diphenylmethane diisocyanate was used as a hardener. The films of the dual‐cured coating, obtained from UV‐cured or room temperature‐cured process, showed an excellent tensile strength, elongation at break, impact resistance, and lightfastness when compared with traditional UV and PU coatings; especially, the adhesion of UV/PU dual‐cured coating by UV‐cured process was better than that of traditional UV coating. It can therefore be concluded that the epoxy acrylate oligomer‐based dual‐cured coating could readily be used for complicated wood products finishing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Optimal preparation and characterization of poly(urea–formaldehyde) microcapsules
Authors: Ting Zhang , Min Zhang , Xiao‐Mei Tong , Feng Chen , Jian‐Hui Qiu 
Published: October 2009

AbstractMicrocapsules with epoxy curing agent were successfully prepared by an in‐situ polymerization route with epoxy resin and poly‐(urea–formaldehyde) as core and shell materials, respectively. The synthetic conditions were optimized by a comprehensive investigation on raw materials consumption, size distribution, and surface morphology. Preparation of microcapsules with high wrap ratio was also demonstrated. The as‐synthesized microcapsules were studied using various characterizations techniques, including optical microscope, fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and contact angle meter. Spherical microcapsules (size: ∼ 60 μm) with smooth surface were obtained when the stirring rate was 400 rpm and the amount of core materials is 76 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Optical properties of particle‐filled polycarbonate, polystyrene, and poly(methyl methacrylate) composites
Authors: Zhou Rui‐Juan , Burkhart Thomas 
Published: October 2009

AbstractTransparency is a key material property of polycarbonate (PC), polystyrene (PS), and poly(methyl methacrylate) (PMMA). To study the optical properties of particle‐filled PC, PS, and PMMA, composites containing inorganic particles in different sizes and concentrations were produced by direct melt mixing in this work. The optical properties characterized by total light transmittance, haze, and clarity were studied. The results show that the optical properties of polymer composites are strongly affected by particle content, particle size, and especially by difference in refractive indices between polymer matrix and particles. It is also revealed that the light transmittance and haze of composites are mainly affected by difference in refractive indices, whereas the clarity is more affected by particle size. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Ring opening polymerization of ε‐caprolactone initiated by decamolybdate anion: Determination of kinetic and thermodynamic parameters by DSC and 1H‐NMR
Authors: Ramírez‐Hernández Aurelio , Martínez‐Richa Antonio 
Published: October 2009

AbstractThe aim of this work is the kinetic and thermodynamic study (by differential scanning calorimetry (DSC) and proton nuclear magnetic resonance (1H‐NMR)) of the polymerization of ε‐caprolactone initiated by ammonium decamolybdate. By means of isothermal kinetics, enthalpies of reaction in the range 150–160°C, as well as constant rates of polymerization (using an nth‐order kinetics function model), were determined. From an Arrhenius plot, activation energy (Ea = 85.3 kJ/mol) and preexponential factor (A = 1.78 × 108 min−1) were estimated. Using dynamic methods, crystallization and melting temperatures for the polymer obtained in situ were derived. Kinetic data for polymerization (obtained by 1H‐NMR) were fitted to 13 different model reaction functions. It was found that power law equations represent better the conversion versus time plots for this system. On the basis of experimental facts, a coordination‐insertion mechanism involving molybdenum(V) species is proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of poly(acrylic acid) molecular mass and end‐group functionality on calcium oxalate crystal morphology and growth
Authors: East Christopher P. , Wallace Andrew D. , Al‐Hamzah Ali , Doherty William O. S. , Fellows Christopher M. 
Published: October 2009

AbstractA number of series of poly(acrylic acids) (PAA) of differing end‐groups and molecular mass were used to study the inhibition of calcium oxalate crystallization. The effects of the end‐group on crystal speciation and morphology were significant and dramatic, with hexyl‐isobutyrate end groups giving preferential formation of calcium oxalate dihydrate (COD) rather than the more stable calcium oxalate monohydrate (COM), while both more hydrophobic end‐groups and less‐hydrophobic end groups led predominantly to formation of the least thermodynamically stable form of calcium oxalate, calcium oxalate trihydrate. Conversely, molecular mass had little impact on calcium oxalate speciation or crystal morphology. It is probable that the observed effects are related to the rate of desorption of the PAA moiety from the crystal (lite) surfaces and that the results point to a major role for end‐group as well as molecular mass in controlling desorption rate. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Seawater degradable thermoplastic polyurethanes
Authors: Moravek Scott J. , Hassan Mohammad K. , Drake David J. , Cooper Tim R. , Wiggins Jeffrey S. , Mauritz Kenneth A. , Storey Robson F. 
Published: October 2009

AbstractDegradable thermoplastic polyurethane (TPU) elastomers incorporating poly(D,L‐lactide‐co‐glycolide) (PLGA) were synthesized and characterized. The soft segments consisted of a mixture of poly(butylene adipate) (PBA) and PLGA with PBA/PLGA ratios of 100/0, 75/25, and 50/50 wt %. Two PLGA polyesters were used. BD‐PLGA was initiated from butanediol; whereas BHMBA‐PLGA was initiated from 2,2‐bis‐(hydroxymethyl)butanoic acid. The hard segments consisted of dicyclohexylmethane‐4,4′‐diisocyanate (H12MDI) and 1,4‐butanediol (BD). The hard segment content, expressed as the weight ratio of BD to polyol used in the TPU formulation, was set either at 8 or 12% (31.2 or 38.1% hard segment by weight, respectively). In all cases initial [NCO]/[OH] ratio was 1.03. The tensile modulus of the TPUs ranged from 9 to 131 MPa and ultimate strains ranged from 100 to 750%. DMA was used to probe the thermomechanical transitions of the TPUs and indicated useful application temperatures from well below zero up to 60–80°C depending on the formulation. Hydrolytic degradation of the TPUs was tested in seawater at 37°C. All of the PLGA‐containing TPUs showed enhanced degradation compared to those with only PBA as the soft segment. The latter compositions remained essentially unchanged throughout the test while the PLGA‐containing TPUs lost as much as 45% of their initial mass in 153 days. Molecular weights of TPUs containing degradable polyols were lower than those derived from 100% PBA polyol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation of anion exchange membrane by amination of chlorinated polypropylene and ethylenediamine and its properties
Authors: Hong Joo‐Hee , Hong Sung‐Kyu 
Published: October 2009

AbstractAn anion exchange membrane was prepared by amination of chlorinated polypropylene (CPP) and ethylenediamine (EDA) at a low temperature and was investigated with respect to not only its physical properties but also its electrochemical properties. The degrees of amination were 46.05, 47.07, 50.56, and 56.58% at 30, 40, 50, and 55°, respectively. The CPP membrane had no water uptake, whereas, that of the CPP‐EDA membrane was 0.153, 0.243, 0.309, and 0.410 g of H2O/g of dry membrane, respectively, with increasing amination. The CPP‐EDA membranes possessed an ion exchange capacity in the range 0.557–1.498 mequiv/g of dry membrane and a fixed ion concentration in the range 4.198–5.114 mequiv/g of H2O. The ionic conductivity of the CPP‐EDA membrane was highest when the water uptake was highest. Those of the CPP‐EDA membrane were in the range 0.475 × 10−2–0.999 × 10−2 S/cm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Crosslinking of epoxidized natural oils with diepoxy reactive diluents
Authors: Demengeot Emmanuelle‐Anita‐Claude , Baliutaviciene Inga , Ostrauskaite Jolita , Augulis Liudvikas , Grazuleviciene Violeta , Rageliene Lina , Grazulevicius Juozas Vidas 
Published: October 2009

AbstractThe different natural oils epoxidized with 3‐chloroperbenzoic acid were crosslinked with diepoxy reactive diluents, bisphenol A propoxylate diglycidyl ether, and 3,4‐epoxycyclohexylmethyl‐3,4‐epoxyclohexane‐carboxylate, using cationic initiator at 60°C and photoinitiators at the room temperature. The insoluble fraction of the polymeric products was 59–90%. The Young modulus of the crosslinked polymer films ranged from 2 to 861 MPa. The 10% weight loss temperatures of the crosslinked polymers estimated by thermogravimetric analysis were in the range from 250 to 420°C. The water vapor transmission rate of the crosslinked biopolymer films ranged from 6 to 49 g/m2/24 h. Biochemical oxygen demand and biodegradation in soil of the crosslinked polymers were studied. The crosslinked polymers showed higher biodegradation rate than cellulose, starch, and polyvinylalcohol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fouling control in a submerged membrane‐bioreactor by the membrane surface modification
Authors: Li Wei , Zhou Jin , Gu Jia‐Shan , Yu Hai‐Yin 
Published: October 2009

AbstractTo improve the antifouling characteristics, polypropylene microporous membranes (PPHFMMs) were surface‐modified by the sequential photoinduced graft polymerization of acrylic acid and acrylamide. The grafting density and the grafting chain length, which played important roles in the antifouling characteristics, were controlled in the first and the second step, respectively. The ATR/FTIR results clearly indicated the successful modification on the membrane surface. The static water contact angle of the modified membrane reduced obviously with the increase of the grafting chain length. The contact angle of the acrylic acid modified membranes was lower than that of the acrylamide modified membrane with similar grafting chain length. The grafting chain length increased with the increase of UV irradiation time and monomer concentration. The grafting chain length of poly(acrylic acid) (PAAc) was lower than that of the polyacrylamide (PAAm) under the same polymerization conditions. Pure water flux for the modified membranes increased with the increase of grafting chain length, and had maximums. The antifouling characteristics of the modified membranes in a submerged membrane‐bioreactor (SMBR) were evaluated. The modified membranes showed better filtration performances in the SMBR than the unmodified membrane, and the acrylic acid grafted membrane presented better antifouling characteristics than acrylamide modified membranes. The results demonstrated that the surface carboxyl‐containing membranes were better than the surface amido‐containing membranes. The results of Pearson correlations demonstrated that the PAAc modified membranes with longer grafting chain length had higher flux recoveries, while the PAAm modified membranes with longer grafting chain length had lower flux recoveries. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of novel optically active polyurethanes containing 1,1′‐binaphthol
Authors: Chen Jing , Nan Qiuli , Guo Lingxiang , Zhou Yuming 
Published: October 2009

AbstractNovel optically active polyurethanes (BPUs) based on chiral 1,1′‐binaphthol were synthesized via direct hydrogen transfer addition polymerization. The polymers were analyzed by FTIR, 1H NMR, DSC‐TGA, CD spectra.The results showed that the specific rotation [α]25D were −78.0° and +54.6° for the S‐BPU and R‐BPU respectively, and these polymers showed better thermal stability. The circular dichroism spectra of the chiral polymers were almost identical except that they gave opposite signals at each wavelength, and the infrared emissivity values of the S‐BPU and R‐BPU were 0.618 and 0.682, they displayed low infrared emissivity. Meantime the polymers implanted with PEG group exhibit better solubility, however thermal stability reduced to some extent. Some properties of the new optically active polyurethanes were reported. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
New binary systems containing TMTD‐amidino phenyl thiourea and CBS–amidinophenyl thiourea for the vulcanization and rheological behavior of natural rubber latex
Authors: Susamma A. P. , Claramma N. M. , Nair Ajalesh B. , Kuriakose A. P. 
Published: October 2009

AbstractThe use of accelerators in rubber latex is basically different from their use in dry rubber. In the present study, N amidino N'phenyl thiourea (APT) which is more nucleophilic than thiourea was studied as a secondary accelerator along with tetra methyl thiuram disulphide (TMTD) and N‐cyclohexylbenzothiazyl sulphenamide (CBS) in the vulcanization of natural rubber latex. These binary systems were found to be very effective in reducing the vulcanization time. The optimum dosages for this non‐toxic secondary accelerator required were derived. Rheological studies of the compounded latex show that the introduction of APT in these systems does not have adverse effect in processing in comparison with the thiourea systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and in vitro release behavior of urapidil hydrochloride loading into microspheres based on poly(L‐lactide)
Authors: Hong Hao , Rongjie Liu , Ting Lan , Genyao Lin 
Published: October 2009

AbstractMicroencapsulation of the antihypertensive drug urapidil hydrochloride was investigated as a means of controlling drug release and minimizing or eliminating local side effects. Poly(L‐lactide) (PLLA) microspheres were prepared using an alternative oil‐in‐water (O/W) solvent‐evaporation method such as the O/W cosolvent solvent‐evaporation method and O/W with various electrolytes added to the aqueous phase method. The surface morphology and the size of the microspheres were observed by scanning electron microscope. Meanwhile, the drug loading efficiency of microspheres and the in vitro release of urapidil hydrochloride from microspheres were performed. The release study indicated that the urapidil hydrochloride‐PLLA microspheres exhibited better sustained release capacity, and the kinetics of urapidil hydrochloride‐PLLA microspheres in vitro release could be described by the Higuchi equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Interstitial deletion of 18q: Comparative genomic hybridization array analysis of 46, XX,del(18)(q21.2.q21.33)
Authors: Kato Zenichiro , Morimoto Wataru , Kimura Takeshi , Matsushima Akihiro , Kondo Naomi 
Published: October 2009

AbstractBACKGROUND: Interstitial deletion of chromosome 18q is rare, making it difficult to assign phenotypes to particular cytogenetic deletions. CASE: We present an 18‐year‐old female with an interstitial deletion of chromosome 18q21.2–q21.33. The clinical features included severe psychomotor retardation with mild growth retardation, hypotonia, midfacial hypoplasia, carp‐shaped mouth, hypertelorism, strabismus, narrow upward slant palpebral fissures, short philtrum, everted lower lip, malformed ears, flat nasal bridge, and epicanthic folds. Brain abnormalities, such as agenesis of the corpus callosum, and abnormalities of the hands and feet were absent. Initially, the deletion was recognized as 18q21.1–q21.31 by conventional chromosomal analysis, and microarray‐based comparative genomic hybridization revealed a 9.6‐Mb deletion at 18q21.2–q21.33. The deletion included the transcription factor 4 gene and the methyl‐CpG binding domain protein 2 (MBD2) gene, but not the MBD1 gene. CONCLUSIONS: The deletion of the transcription factor 4 gene suggested a possible contribution of the deletion to the patient's facial abnormalities, as observed in Pitt‐Hopkins syndrome. Together with other reported cases with interstitial deletion of 18q, a possible contribution of haploinsufficiency in both MBD1 and MBD2 genes to a Rett syndrome‐like phenotype was suggested, but further genetic studies on other cases are necessary to clarify the genotype‐phenotype correlation. Birth Defects Research (Part A), 2010. © 2009 Wiley‐Liss, Inc.
Factors predicting arrest for homeless persons receiving integrated residential treatment for co‐occurring disorders
Authors: Barrett Blake , Young M. Scott , Moore Kathleen , Borum Randy , Ochshorn Ezra 
Published: October 2009

AbstractBackground Homeless individuals are at increased risk for health and criminal justice problems.Aims The aim of this study was to examine risk factors affecting arrest rates in a cohort of homeless people with co‐occurring psychiatric and substance‐abuse disorders.Methods Baseline data were collected from 96 homeless individuals residing in a residential treatment facility for people with co‐occurring disorders. Arrest data were obtained for 2 years following treatment intake. Regression analyses were employed to examine interactions between study variables.Results One third of the sample was arrested during the 2‐year follow‐up period, principally for drug offences. People referred to treatment directly from the criminal justice system were four times more likely to re‐offend than those referred from other sources. Participants' perceived need for mental‐health services reduced risk of arrest while their perception of medical needs increased this risk.Conclusions The relationship between referral from a criminal justice source and re‐arrest after admission to the treatment facility is unsurprising, and consistent with previous literature, but the suggestion of an independently increased risk in the presence of perceived physical health‐care needs is worthy of further study. The lower risk of arrest for people who perceive that they have psychological needs is encouraging. Copyright © 2009 John Wiley & Sons, Ltd.