bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and electroluminescence properties of a novel poly(paraphenylene vinylene)‐based copolymer with tri(ethylene oxide) segments on the backbone
Authors: Wang Haiqiao , Duan Lian , Qiu Yong , Wang Xiaogong , Liu Deshan 
Published: August 2002

AbstractA novel light‐emitting copolymer [tri(ethylene oxide)–poly(paraphenylene vinylene) (TEO–PPV)] containing alternating rigid, conjugated distyrylbenzene [poly(paraphenylene vinylene) model oligomer] as light‐emitting units and flexible tri(ethylene oxide) as ionic conductive units was synthesized. The polymer was characterized with Fourier transform infrared, 1H‐NMR, ultraviolet–visible spectroscopy, differential scanning calorimetry, and gel permeation chromatography. TEO–PPV has excellent solubility in conventional organic solvents such as tetrahydrofuran, chloroform, benzene, and toluene. The estimated lowest unoccupied molecular orbital, highest occupied molecular orbital, and band gap are 2.35, 5.29, and 2.94 eV, respectively. Single‐layer and double‐layer light‐emitting diodes with indium tin oxide anodes and calcium cathodes were fabricated, and the photoluminescence (PL) and electroluminescence (EL) properties were investigated. The maximum EL emissive peak (475 nm) of the devices is essentially the same as that of PL. Anomalous current–voltage characteristics were observed in both devices. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2195–2200, 2002
Effect of dopant mixture on the conductivity and thermal stability of polyaniline/nomex conductive fabric
Authors: Kim Seong Hun , Seong Jea Hwan , Oh Kyung Wha 
Published: August 2002

AbstractElectrically conductive polyaniline (PANI)/[poly(m‐phenylene isophthalamide)] Nomex composite fabric was prepared by in situ polymerization of aniline doped by a mixture of hydrochloride (HCl) and various sulfonic acids such as benzenesulfonic acid (BSA), sulfosalicylic acid (SSA), and dodecylbenesulfonic acid (DBSA); their effect on conductivity and physical properties were then investigated. PANI/Nomex composite fabrics doped by a mixture of protonic acids exhibited higher conductivity than those doped by other single dopants such as camphorsulfonic acid (CSA), p‐toluenesulfonic acid (TSA), BSA, SSA, and HCl. The conductivity of PANI/Nomex fabrics especially doped by a mixture of HCl and DBSA was evenly maintained up to 100°C without depression of mechanical properties of Nomex. Their conductivity was also maintained under extension of the composite fabric. In addition, electrical conductivity of PANI/Nomex fabrics was highly increased by ultrasonic treatment, which facilitated better diffusion and adsorption of aniline by cavitation and vibration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2245–2254, 2002
Morphology structure study of polypropylene hollow fiber membrane made by the blend‐spinning and cold‐stretching method
Authors: Mei Li , Zhang Dasheng , Wang Qingrui 
Published: August 2002

AbstractThis paper proposes one of simplest ways to prepare polypropylene/easy hydrolytic degradation polyester (PP/EHDPET) microporous hollow fibers by blend spinning and cold stretch process. And it details and investigates the structure properties of as‐spun fibers, micropore formation mechanism, and pore structure of the hollow fiber membranes by the scanning electron microscope. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1390–1394, 2002; DOI 10.1002/app.10280
Effects of resin chemistry on redox polymerization of unsaturated polyester resins
Authors: Yang Huan , Lee L. James 
Published: August 2002

AbstractUnsaturated polyester resins are the most widely used thermoset resins in the composite industry. In this study, three well‐defined unsaturated polyester resins were used. These resins have similar number‐average molecular weights, and they have different numbers of CC bonds per molecule. The reaction kinetics of unsaturated polyester resins was studied using a differential scanning calorimeter (DSC) and a Fourier transform infrared (FTIR) spectrometer. The glass transition temperature of the isothermally cured resin was also measured. Trapped radicals were observed in the cured polyester resin from electron spin resonance (ESR) spectroscopy. Considering the diffusion‐limitation effect, a simple kinetic model was developed to simulate the reaction rate and conversion profiles of polyester vinylene and styrene vinyl groups, as well as the total reaction rate and conversion. Experimental results from DSC and FTIR measurements compare favorably with the model prediction. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 211–227, 2002; DOI 10.1002/app.10317
Synthesis and characterization of emulsion copolymer of N‐cyclohexylmaleimide and methyl methacrylate
Authors: Yang Liting , Sun Donghai , Li Yanfang , Liu Guodong , Gao Jungang 
Published: August 2002

AbstractCopolymers of N‐cyclohexylmaleimide (ChMI) and methyl methacrylate (MMA) were synthesized by the emulsion semibatch copolymerization method. The effects of the monomer mixture composition on the average molecular weight (Mn and Mw), glass transition temperature (Tg), degradation temperature, mechanical properties, and rheological behavior of the copolymers were investigated. The results show that Mn and Mw have maximum values when the ChMI feed content was about 20% (by wt). The degradation temperature and Tg of the copolymers increase with increasing ChMI moieties in the copolymer. The mechanical properties (tensile strength and impact strength) decrease with an increasing ChMI feed content. All copolymers in the melt show pseudoplastic behavior. The flow index n increases with an increasing ChMI feed content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1070–1075, 2002; DOI 10.1002/app.10394
Effect of the compatibilization of linear low‐density polyethylene‐g‐acrylic acid on the morphology and mechanical properties of poly(butylene terephthalate)/linear low‐density polyethylene blends
Authors: Yang Jinghui , Shi Dean , Yao Zhanhai , Xin Zhirong , Yin Jinghua 
Published: August 2002

AbstractA poly(butylene terephthalate) (PBT)/linear low‐density polyethylene (LLDPE) alloy was prepared with a reactive extrusion method. For improved compatibility of the blending system, LLDPE grafted with acrylic acid (LLDPE‐g‐AA) by radiation was adopted in place of plain LLDPE. The toughness and extensibility of the PBT/LLDPE‐g‐AA blends, as characterized by the impact strengths and elongations at break, were much improved in comparison with the toughness and extensibility of the PBT/LLDPE blends at the same compositions. However, there was not much difference in their tensile (or flexural) strengths and moduli. Scanning electron microscopy photographs showed that the domains of PBT/LLDPE‐g‐AA were much smaller and their dispersions were more homogeneous than the domains and dispersions of the PBT/LLDPE blends. Compared with the related values of the PBT/LLDPE blends, the contents and melting temperatures of the usual spherulites of PBT in PBT/LLDPE‐g‐AA decreased. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1059–1066, 2002; DOI 10.1002/app.10399
Chemical synthesis and characterization of some conducting polyaniline derivatives: Investigation of the effect of protonation medium
Authors: Gök Ayşegül , Sari Beki̇r 
Published: August 2002

AbstractPoly(o‐toluidine) (POT) and poly(2‐chloroaniline) (P2ClAn) emeraldine salts were synthesized chemically by using formic (HCOOH), acetic (CH3COOH), propionic (C2H5COOH), and boric (H3BO3) acids. Ultraviolet‐visible absorption spectra (UV–Vis) analysis results indicated that POT has the better protonation effects than P2ClAn. Among the POTs synthesized using the four different acids, POT(H3BO3) showed the least protonation effect. The conductivities of prepared polymers were measured by a four‐probe technique. The highest conductivities were obtained in POTs synthesized by using formic, acetic, and propionic acids. Magnetic susceptibility measurements of the polymer salts were analyzed by using Gouy scale and it was found that POT(CH3COOH) and POT(C2H5COOH) salts are of bipolaron structure; other polymer salts are of polaron structure. The characterization of the polymers were investigated by Fourier infrared spectroscopy (FTIR), UV–Vis, thermogravimetric analysis, and scanning electron microscopy. It was observed from UV–Vis spectra of the emeraldine salt of POT that wavelengths belonging to π → π* transitions shifted to shorter wavelengths with increasing pKa values of acids. POT and P2ClAn synthesized in four different protonation media decomposed with three‐step and three‐ or two‐step weight loss, respectively. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1993–2000, 2002; DOI 10.1002/app.10487
Free radical copolymerization of tert‐butyl 3‐isopropenylcumylperoxide with styrene and grafting of methyl methacrylate onto the copolymers
Authors: Guo Xingpeng , Li Zhiang , Du Qiangguo , Yang Yuliang , Lin Mingde 
Published: August 2002

AbstractCopolymers of tert‐butyl‐3‐isopropenylcumylperoxide (D‐120) with styrene (St) were prepared in bulk by using benzoyl peroxide as initiator at 80°C. The compositions of the copolymers were determined by 1H‐NMR analysis. The reactivity ratios of D‐120 and St were calculated by methods of Kelen–TüdÖs (K‐T), Fineman–Ross (F‐R), and Yezrielev‐Brokhina‐Roskin (YBR), respectively. Graft copolymers were obtained by grafting of methyl methacrylate (MMA) onto the copolymers during decomposition of peroxy bonds suspended in the backbone. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2318–2326, 2002
Visible light‐induced polymerization of monooxiranes and 1,5,7,11‐tetraoxaspiro[5.5]undecanes
Authors: Pinzino Charles S. , Chappelow Cecil C. , Holder Andrew J. , Morrill Jason A. , Harris C. David , Power Martin D. , Eick J. David 
Published: August 2002

AbstractThe visible‐light photohomopolymerization reactivities of several monofunctional oxiranes were evaluated using photodifferential scanning calorimetry (PDSC). Two oxiranes, styrene oxide and 1‐methoxy‐2‐methyl propylene oxide, were selected for copolymerization reactivity studies with five substituted 1,5,7,11‐ tetraoxaspiro[5.5]undecanes (TOSUs). Reaction mixtures contained a diaryliodonium salt photoacid initiator and a β‐diketone photosensitizer. Experimentally determined reaction enthalpies were compared with calculated theoretical values to assess percent conversion. Relative reactivities were evaluated by comparing induction and exotherm peak maximum times. Results of AM1 semiempirical quantum mechanical calculations of reaction energetics were compared to experimental findings for selected polymerizations. IR spectral changes were consistent with oxirane and TOSU ring opening. The effect of temperature on the photopolymerization reactivity characteristics of glycidyl methylphenyl ether alone and in combination with unsubstituted TOSU was also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 159–168, 2002
Microporous membranes of polyoxymethylene from a melt‐extrusion process: (II) Effects of thermal annealing and stretching on porosity
Authors: Johnson Matthew B. , Wilkes Garth L. 
Published: August 2002

AbstractA two‐part study utilizing polyoxymethylene (POM) was undertaken to investigate a three‐stage process (melt‐extrusion/annealing/uniaxial‐stretching) utilized to produce microporous films. In this report, the thermal annealing (second stage) and subsequent uniaxial‐stretching (third stage) results of selected POM films from two commercial resins, labeled D & F, are discussed. Specifically, the annealing and uniaxial stretching effects on film morphology, orientation, and other pertinent film properties are addressed. Additionally, sequential analysis was performed regarding the influence each stage had on the resulting microporosity. It was found that the melt‐extruded precursor morphology and orientation, as a consequence of the first stage extrusion parameters and resin characteristics, are crucial to controlling the membrane permeability. The annealing parameters were also deemed critical, where a temperature of 145°C applied for 20 min under no tension was the optimum annealing condition for producing a highly microporous film upon stretching. For the conditions studied, the stretching parameters that were found to be optimum for producing the desired characteristics in the final film were a cold temperature of 50°C and hot stretch temperature of 100°C. The optimum extension levels were concluded to be 90% for both the cold and hot stretch steps, and thus a total overall extension level of 180%. However, these results were only with respect to resin F films. Because the resin D melt‐extruded precursors possessed twisted lamellar morphologies and relatively low crystal orientation, their samples could not be produced into microporous films. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1762–1780, 2002; DOI 10.1002/app.10587
Polyurethane elastomers made from linear polybutadiene diols
Authors: Špírková Milena 
Published: August 2002

AbstractSegmented polyurethane elastomers made from linear polybutadiene diols terminated with primary (Krasol LBH‐P) or secondary (Krasol LBH) hydroxy groups, alicyclic diisocyanate, and aliphatic chain extender were prepared and tested. The system was chemically crosslinked either through isocyanurate, that is, hexahydro‐1,3,5‐triazine‐2,4,6‐trione groups (formed by catalyzed cyclotrimerization of isocyanate groups), or by low molecular weight triols. The best balance of stress‐strain properties and reasonable thermal stability was obtained for systems in which only a small amount of chemical crosslinks was present in predominantly physically crosslinked networks. The influence of the type of polymer diol, chemical crosslinking, diisocyanate, and technique of preparation on mechanical, thermal, and swelling properties is discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 84–91, 2002
Synthesis and study of a new polyorganophosphazene
Authors: Li Feng , Wang Jingyuan , Xie Tengfeng , Wang Dejun , Tang Jun , Tang Xinyi 
Published: August 2002

AbstractIn this study, a new polyorganophosphazene with pendant carbazolyl groups was synthesized, and its structure was characterized by IR, 1H‐NMR, and 31P‐NMR spectroscopy. To understand its carrier photogeneration and transport property, we also studied fluorescence spectra and photovoltage spectra. Fluorescence spectra show that the polymer possesses properties dissimilar to those of PVK. There are only two emission peaks at ≈ 360 nm in its spectra, which coincides with that of the monomer model compound, 9‐ethylcarbazole. This may be because of the influence of the spacer. The results of SPS shows that band–band transition mainly comes from electron π–π* transition, and the polymer is a p‐type semiconductor. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1446–1451, 2001
Polymer mediated growth and morphology in MNA/PMMA guest/host microdispersed composites
Authors: Saujanya C. , Pathak G. , Radhakrishnan S. 
Published: August 2002

AbstractThe structure and morphology in the meta‐nitroaniline (MNA) dispersed poly(methyl methacrylate) (PMMA) guest/host system was investigated with respect to composition and different techniques of crystallization. Large changes in the intensities of various X‐ray diffraction peaks were observed for both solution grown (SC) and melt crystallized (MC) MNA/PMMA composite films. However, in the former case, the peak corresponding to (060) reflection had maximum intensity, while in the latter, the peak corresponding to (112) reflection was most prominent. At low concentrations, the films appeared to be amorphous and transparent, but electron diffraction studies revealed small ordered domains. Both solution and melt grown MNA/PMMA films contained two types of crystallites having different structures: one having the original orthorhombic structure (a = 6.51 Å, b = 19.35 Å, c = 5.07 Å) of bulk MNA, while the other crystallized in new monoclinic phase with a = 13.0 Å, b = 19.35 Å, c = 10.15 Å, and β = 64°. The presence of the new structure that formed could be due to a formation of complex between PMMA and MNA. This complex formation and new structure was further confirmed by differential scanning calorimeter (DSC) and infrared analysis (IR). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1547–1557, 2001
Tensile properties of elastomeric polyolefin thin films: The path to failure
Authors: Eckersley Sarah T. , Chaput A. Bruce 
Published: August 2002

AbstractThe tensile failure of thin films prepared from polyolefin elastomer dispersions was studied. The elastomer dispersions were composed of copolymers of ethylene and 1‐octene, dispersed in water at solids concentrations of approximately 50%. The density of the polyolefin resins ranged from 0.855 to 0.885 g cm−3. The melt index of the resins ranged between 0.5 and 5.0 g 10 min−1. As expected, the tensile strength of neat polyolefin films was found to be a strong function of the density and a weak function of the melt index. Dispersion blends were prepared from neat polyolefin dispersions. The film tensile properties were measured as a function of the blend ratio and the particle‐size ratio. The blend ratio was found to be the dominant factor. It was found that blending the dispersions had an antagonistic effect on the tensile properties. The ultimate tensile strength of the blend film was lower than expected from the arithmetic mean behavior (based on the weight fraction) of the two constituent resins. A similar result was observed for the ultimate elongation, that is, blending of the two elastomers gave inferior behavior. The relationship between the experimental tensile properties and the blend ratio fit a quadratic function. A Monte Carlo simulation was used to model film failure in two dimensions. The two particle types were assumed to pack randomly and failure was forced to occur by the lowest‐energy path. The simulated ultimate tensile strength was also found to be a quadratic function of the blend ratio, confirming the suitability of the model. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2545–2557, 2001
Solvent effects on the miscibility of poly(methyl methacrylate)/poly(bisphenol a carbonate) blends
Authors: Hsu Wen‐Ping 
Published: August 2002

AbstractBlends of atactic or syndiotactic poly(methyl methacrylate) (designated as aPMMA or sPMMA) and poly(bisphenol A carbonate) (PC) were prepared from solution casting. Tetrahydrofuran (THF) and chloroform were used as solvent. Experimental results indicated that the as‐cast blends from THF were quite different from the chloroform‐cast ones. After film preparation, THF‐cast blends did not show any visible phase separation. However, chloroform‐cast blends formed a phase‐separated structure. The as‐cast PC from either solvent was not completely amorphous, and had a melting point at 239–242°C, indicating a certain degree of crystallinity. In contrast, the quenched samples of aPMMA/PC blends prepared from the two solvents behaved virtually the same. They both showed aPMMA dissolves better in PC, but PC solubility in aPMMA is very little. Using sPMMA instead of aPMMA to blend with PC, different results were obtained. The quenched sPMMA/PC blends cast from THF showed only one Tg. However, immiscibility (i.e., two Tgs) was found in the same blend system when cast from chloroform. THF was believed to cause the observation of single Tg due to the following kinetic reason. sPMMA and PC were still trapped together even after THF removal in a homogeneous, but nonequilibrium state below the glass transition. Therefore, the quenched sPMMA/PC blends were not truly thermodynamically miscible. From the results of aPMMA or sPMMA with PC, increasing syndiotacticity seemed to improve the miscibility between PMMA and PC. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2842–2850, 2001
Local polydispersity detection in size exclusion chromatography: Method assessment
Authors: Balke Stephen T. , Mourey Thomas H. 
Published: August 2002

AbstractLocal polydispersity is the term describing the variety of molecules present at the same retention volume in size exclusion chromatography (SEC) analysis. In the analysis of a linear homopolymer, local polydispersity is generally attributed to the effect of axial dispersion: it can cause molecular size variety (i.e., imperfect resolution) at each retention volume and thus local polydispersity in the molecular weight. In the analysis of polymer blends (copolymers and branched polymers), it is possible to have local polydispersity, even when the resolution is perfect, because molecules of different compositions (or degrees of branching) can have the same molecular size in solution. Conventional SEC interpretation assumes no local polydispersity if the axial dispersion effects are negligible. Three methods are currently available for detecting local polydispersity by using a combination of differential refractive index, light scattering, and viscometer detectors: the chromatogram comparison method, the conventional calibration curve comparison method, and the universal calibration comparison method. Here we experimentally assess these three methods using polymer blends and emphasize the chromatogram comparison method. All three are shown to be useful for assessing triple detector systems, but they are capable of detecting local polydispersity due to molecular heterogeneity only for very large differences in specific refractive index increments in the blend components. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 370–383, 2001
Natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) blends
Authors: Thiraphattaraphun L. , Kiatkamjornwong S. , Prasassarakich P. , Damronglerd S. 
Published: August 2002

AbstractThe grafting of the methyl methacrylate (MMA) monomer onto natural rubber using potassium persulfate as an initiator was carried out by emulsion polymerization. The rubber macroradicals reacted with MMA to form graft copolymers. The morphology of grafted natural rubber (GNR) was determined by transmission electron microscopy and it was confirmed that the graft copolymerization was a surface‐controlled process. The effects of the initiator concentration, reaction temperature, monomer concentration, and reaction time on the monomer conversion and grafting efficiency were investigated. The grafting efficiency of the GNR was determined by a solvent‐extraction technique. The natural rubber‐g‐methyl methacrylate/poly(methyl methacrylate) (NR‐g‐MMA/PMMA) blends were prepared by a melt‐mixing system. The mechanical properties and the fracture behavior of GNR/PMMA blends were evaluated as a function of the graft copolymer composition and the blend ratio. The tensile strength, tear strength, and hardness increased with an increase in PMMA content. The tensile fracture surface examined by scanning electron microscopy disclosed that the graft copolymer acted as an interfacial agent and gave a good adhesion between the two phases of the compatibilized blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 428–439, 2001
Peroxide modification of poly(butylene adipate‐co‐succinate)
Authors: Kim D. J. , Kang H. J. , Seo K. H. 
Published: August 2002

AbstractWe attempted to introduce crosslinking into poly(butylene adipate‐co‐succinate) (PBAS) to improve the properties, such as the mechanical strength and elasticity, by a simple addition of dicumyl peroxide (DCP). Prior to curing, the thermal stability of PBAS was investigated. Above 170°C PBAS was severely degraded, and the degradation could not be successfully stabilized by an antioxidant. The PBAS was effectively crosslinked by DCP, and the gel fraction increased as the DCP content increased. A major structure of the crosslinked PBAS was an ester and aliphatic group. The tensile strength and elongation of PBAS were improved with an increasing content of DCP, but there was little affect on the tear strength. The biodegradability of crosslinked PBAS was not seriously deteriorated. A higher degree of crosslinking gave a lower heat of crystallization and heat of fusion. However, the melt crystallization temperatures of the crosslinked PBAS were higher than that of PBAS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 637–645, 2001