bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studies of thermal transition behavior in plasticized poly(vinyl butyral‐co‐vinyl alcohol) with solid‐state NMR and thermal analysis techniques
Authors: Parker A. A. , Hedrick D. P. , Ritchey W. M. 
Published: April 2003

AbstractSamples of plasticized poly(vinyl butyral‐co‐vinyl alcohol) (PVB) are found to exhibit multiple thermal transitions as observed by dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). Arrhenius plots using DSC and DMA data suggest that two of the transitions are glass‐type ones. Variable temperature solid‐state 13C‐NMR experiments show a temperature‐dependent line‐broadening pattern for all PVB backbone carbons with maximum broadening at 55°C or at about 50°C above the second‐order‐type transitions α1 and α2 as measured by DSC. Using Arrhenius plots, the NMR transition is found to best correlate with α1, which is consistent with glass transition behavior. The solid‐state NMR spectra also show that vinyl alcohol tacticity remains unresolved up to a temperature of about 95°C, beyond which line narrowing begins to occur. High‐temperature thermal transitions are also observed by DSC and DMA, which suggest that the onset of motion involving vinyl alcohol sequences may be responsible for these transitions.
Fibers made from concentrated viscose solutions
Authors: Laszkiewicz B. , Wcislo P. , Cuculo J. A. 
Published: April 2003

AbstractCellulose xanthate solutions with α‐cellulose content from 9 to 14% were obtained and their properties were examined. It has been found that viscoses containing urea are more stable and possess lower viscosity as compared with conventional viscoses. Properties of fibers obtained from viscoses with increased α‐cellulose content were discussed. It has also been found that such fibers show higher linear density and their tensile strength depends on the α‐cellulose content in the viscose.
Study by means of computerized spectroscopy of copolymerization grafting
Authors: Rodríguez A. S. , López B. E. M. , Fucugauchi L. A. 
Published: April 2003

AbstractExperiments were performed in an attempt to explain the probable mechanism present in the polymeric grafting process and to determine the percentual ratio between N‐4‐[4‐(dietylamine) fenil] fenilmetilene‐2–5‐cyclohexadiene‐1‐ilidene‐N‐etil ammonium monomer and the sulfate (1 : 1) (Green Vinyl Malachite: GVM) in poly‐N‐vinylcarbazole/Green Vinyl Malachite, PNVC/GVM, specimens of the copolymerization product. Computerized spectroscopic techniques, optimized for maximum absorption and minimum effect noise, were utilized to subtract the spectral information of the GVM monomer noncopolymerized species from the macromolecular base with no special sampling techniques. The samples were processed using the standard PECDS software with the infrared Data Station. The copolymerization process resulted in a 52.91% concentration of a noncopolymerized fraction consisting of dimerized structures of the reactant monomer.
Studies on the effect of an external flaw on the tensile strength of short kevlar fiber–thermoplastic polyurethane composites
Authors: Kutty Sunil K. N. , Nando Golok B. 
Published: April 2003

AbstractThe effect of an external flaw on the tensile strength of short kevlar fiber–thermoplastic polyurethane (TPU) composites has been studied with respect to fiber content, fiber orientation, location of the external flaw, and the temperature of test. The composites showed a three‐step reduction in tensile strength with increasing flaw size. The critical flaw‐length region was shifted to higher flaw‐size levels with increasing fiber content. With increasing temperature, the critical flaw length was increased in the case of unfilled TPU, whereas it remained more or less constant in the case of short kevlar fiber‐filled–TPU composite.
Flame‐retardant PVC compound for cable applications
Authors: Reddy P. V. , Sridhar S. , Ratra M. C. 
Published: April 2003

AbstractThe low‐melting ternary sulfate and modified sulfate glasses based on transition metals like copper, nickel, and vanadium reduce the smoke generation during burning of the PVC compound. With increase in concentration of these glasses, the smoke‐density rating values decrease without appreciably altering the oxygen index values. Although trihydrated alumina and potash alum improve flame‐retarding properties, the latter cannot be used as it considerably reduces the thermal stability of the PVC compound. Formulations to meet the flame‐retardant requirements of a PVC compound suitable for cable sheathing have been developed.
Nylon 4/HEMA chemical homografted membrane
Authors: Lai J. Y. , Chen M. H. , Hsu K. Y. 
Published: April 2003

AbstractTo enhance the degree of grafting, homografting copolymerization of 2‐hydroxyethyl methacrylate (HEMA) onto nylon 4 using a chemical initiator has been attempted. The factors that affect the grafting copolymerization are the concentration of reactants, reaction time, and temperature. The dialysis permeabilities of solutes, water content, surface energy, mechanical properties, and blood compatibility of the membrane were investigated. Under the same reaction conditions, the degree of grafting by the homografting method is remarkably higher than of the heterografting method for the nylon 4–HEMA grafting system. The dialysis permeabilities of NaCl, vitamin B12, and ovalbumin of the homografted membrane with a 14.8% degree of grafting are 2.760, 0.392, and 0.073 × 10−5 cm2/min, respectively. These permeabilities are higher than the corresponding ones of ungrafted nylon 4 membrane. The mol ratios of adsorbed fibrinogen/albumin (F/A) of the heterografted membranes were found to decrease from 0.53 to 0.33, and the surface energy, to increase from 40.6 to 46.4 dyn/cm with the degree of grafting in the range of 12.5–29.9%, and their relationship is not remarkable for the homografted membranes for which the mol ratios of F/A are about 0.22–0.32 with the degree of grafting in the range of 14.8–103.8%. Observed from scanning electron micrographs of the membrane surface, denseness was found to be important to improve blood compatibility. Based on the dialysis permeabilities of solutes and the blood compatibility observed in this study, the homografted nylon 4/HEMA membrane can be considered as a hemodialysis material.
New composite reverse osmosis membranes made from poly‐2‐vinylimidazoline
Authors: Hurndall M. J. , Jacobs E. P. , Sanderson R. D. 
Published: April 2003

AbstractNovel ultra‐thin film (UTF) composite reverse osmosis (RO) membranes were fabricated in situ by the interfacial polymerization of poly‐2‐vinylimidazoline (PVI) precursors and aromatic acid chloride crosslinking agents. The syntheses of three different forms of PVI, which were used as precursors, are described. 3‐(Chlorosulphonyl)benzoyl chloride, 3,5‐di(chlorosulphonyl)benzoyl chloride and 1,3‐benzenedicarbonyl dichloride were used as crosslinking agents. Both flat‐sheet and tubular membranes were fabricated and tested for their salt retentions and permeate fluxes. The RO performances of the two sets of tubular membranes PVI I and PVI II crosslinked with 3‐(chlorosulphonyl)benzoyl chloride, prepared according to optimized fabrication formulations, were recorded. These were 97.1 ± 0.1% retention; 730 ± 24 lmd flux and 98.2 ± 0.7% retention; 560 ± 150 L/m2/day (lmd) flux, respectively. The RO performances of initial tubular membranes made from PVI III and 3‐(chlorosulphonyl)benzoyl chloride was 97.0 ± 1.1% retention and 643 ± 74 lmd flux.
Compatibility studies on some solutions of rubber blends by ultrasonic techniques
Authors: Sidkey M. A. , Fattah A. M. Abd El , Abd El All N. S. 
Published: April 2003

AbstractThe degree of compatibility of the blend solutions, SBR—NR, SBR—BR, and SBR—NBR, dissolved in toluene was studied using ultrasonic methods. The variation of longitudinal ultrasonic velocity with composition is linear with SBR—NR and SBR—BR blends indicating compatible systems. For SBR—NBR the plots of ultrasonic velocity versus composition deviates from linearity according to the degree of compatibility of this blend system. The behavior was confirmed by heat of mixing calculations as well as ultrasonic attenuation measurements.
Oligomerization reactions in acrylonitrile‐N‐Naphthyl‐N′‐acryloylthiourea copolymers in the solid state
Authors: Hamza S. M. , Aly I. M. 
Published: April 2003

AbstractN‐naphthyl‐N′‐acryloylthiourea homopolymer (PNAT) and a series of copolymers of acrylonitrile (AN) with N‐naphthyl‐N′‐acryloylthiourea (NAT) have been prepared and characterized by a variety of analytical and spectral methods. Thermogravimetry (TG) and differential thermal analysis (DTA) data showed that the homopolymer (PNAT) undergoes homolytic scission followed by depolymerization and decomposition upon heating. On the other hand the comonomer (NAT) initiates the nitrile oligomerization reaction in the copolymers upon heating. A mechanism for the initiation of the NAT units in the nitrile copolymers was also proposed.
Surface modification of polyethylene powder using plasma reactor with fluidized bed
Authors: Inagaki N. , Tasaka S. , Abe H. 
Published: April 2003

AbstractThe fluidization technique was applied for the surface modification of powder by plasma, and whether the technique was a practically useful one in the surface modification of powder or not was discussed. Polyethylene powder was used as a specimen to be modified. The oxygen plasma treatment of the polyethylene powder in the fluidized state showed a capability that the surface of the powder was changed from hydrophobic to hydrophilic. The contact angle of water for the treated powder surface was 51°C, which was estimated from the dynamic wicking data. The hydrophilic surface modification of the polyethylene powders in the fluidized bed required the operation of the plasma treatment for at least 3 h. The requirement of the plasma operation for long time rises mainly from large surface area of the powder. The oxygen plasma treatment led to the formation of oxygen functionalities including C  O and C(O)O groups at the outermost layer of the powder. The concentration of the CO and C(O)O functionalities reached 10 and 6% of the total carbon elements being in the XPS sampling depth, respectively. From these results we conclude that the fluidization technique is a useful manner in the surface modification of powder by plasma.
Effect of titanate coupling agent on electromagnetic interference shielding effectiveness and mechanical properties of PC–ABS–NCF composite
Authors: Chiang Wen‐Yen , Chiang Yung‐Shin 
Published: April 2003

AbstractNickel‐coated carbon fibers (NCF) treated with a coupling agent (CA) have been used for preparing composites of polycarbonate (PC) and acrylonitrile—butadiene—styrene (ABS) (90/10%) by melt blending. These composites have been evaluated for electromagnetic interference shielding effectiveness (EMI SE), mechanical properties, dispersion, and adhesion of the polymer to a filler using the scanning electron microscope (SEM). There is an improvement in the EMI SE, tensile strength, and impact strength of the composite when the carbon fiber is coupled with titanate CA. In loading NCF in composite, the optimum concentration of the CA Lica 38 used is about 2.0 phf combined with 1.5 phf calcium stearate (Ca.st.) (on the weight percentage of fillers); the composite can reach an SE of 50 dB by the coaxial transmission line test method.
Gelatin‐based composite polymers
Authors: Xu G. , Ruckenstein E. 
Published: April 2003

AbstractComposite polymers containing gelatin and polymethyl methacrylate (PMMA) have been prepared by employing a gel pathway. The gels have been obtained by mixing mechanically at 50°C an aqueous solution of gelation containing a surfactant (sodium dodecylsulphate, SDS) with a monomer (methyl methacrylate, MMA) containing an initiator (AIBN). Two kinds of gels have been identified: high‐viscosity liquid gels, which lose their stability after half to two hours at room temperature, and solid‐type gels, which maintain their stability for a long time at room temperature. Composite polymer materials have been obtained by the polymerization of MMA in these gels. The polymerization of liquid‐type gels has been carried out in two steps: under mixing for the first hour and without mixing for 23 h. The polymerization of the solid‐type gels was performed in two different ways: (1) at room temperature for a few days followed by heating at 50°C for 4 h, and (2) the same procedure as for the liquid‐type gels (since at 50°C the solid‐type gels transform in liquid‐type gels).The phase behavior of the gels was investigated and scanning electron microscopy (SEM) was used to examine the morphology of the composite polymers. The swelling experiments have shown that at suitable gelatin concentrations, these composites are insoluble in water, methanol, octane, and cyclohexane but have a relatively high solubility in toluene.
Particle morphology in artificial composite polymer latex systems
Authors: Chen Yi‐Cherng , Dimonie Victoria , El‐Aasser Mohamed S. 
Published: April 2003

AbstractArtificial composite latex particles were prepared by direct emulsification of a toluene solution of a blend of polystyrene (PS) and poly(methyl methacrylate) (PMMA). The morphology of the composite particles from the higher molecular weight polymers showed polystyrene particles partially encapsulated by PMMA on the surface. On the other hand, for the lower molecular weight polymers, the reverse morphology was observed. The morphologies of the artificial composite latex particles swollen with solvent were examined when kept under agitation. The degree of phase separation between the two polymers in the composite particles was found to be affected by agitation to different extent, depending on the viscosity of polymer phases, the interfacial tension, and degree of mixing at interface between the two polymers. Extended agitation of the composite latex particles of high molecular weight polymers resulted in mixed morphologies that included individual PS and PMMA particles along with the original morphology of the composite particles. On the other hand, composite latex particles with the lower molecular weight polymers resisted complete phase separation due to lower interfacial tension and better mixing at the interface between the two polymers.
Effect of alkalies on suspension polymerization of vinyl acetate monomer, properties of poly(vinyl acetate) beads and poly(vinyl alcohols)
Authors: Verma S. K. , Arvindakshan P. , Bisarya S. C. 
Published: April 2003

AbstractThe use of weak alkalies such as sodium carbonate (Na2CO3), sodium bicarbonate (NaHCO3) and their 1 : 1 molar mixture, and strong alkalies such as sodium hydroxide (NaOH) and sodium methoxide (NaOMe) as pH controllers in suspension polymerization of vinyl acetate monomer (VAM) has shown to have diverse effects on the yield of resulting poly(vinyl acetate) (PVAC) beads. Carbon dioxide as such or the carbonate seems to influence the yield. Further, these alkalies have a deep‐seated effect not only on properties like viscosity, stereoregularity, glass transition temperature (Tg), and swelling coefficient (Q) of the PVAC beads but also on those of poly(vinyl alcohol) (PVA) obtained by alcoholysis of PVAC beads. The PVAC beads obtained using Na2CO3 showed higher viscosity, higher swelling coefficient (Q), and the PVA derived from these beads had higher Q, higher syndiotacticity/isotacticity ratio, and lower Tg.
Diffusion and sorption of organic liquids through polymer membranes. VIII. Elastomers versus monocyclic aromatic liquids
Authors: Harogoppad Shivaputrappa B. , Aminabhavi Tejraj M. 
Published: April 2003

AbstractSorption and diffusion of five monocyclic aromatic liquids—three halogenated benzenes, nitrobenzene, and aniline—with five engineering polymers—ethylene propylene diene ter‐polymer, nitrile butadiene rubber, styrene butadiene rubber, natural rubber, and neoprene—have been investigated in the temperature interval of 25–60°C. Solvent diffusivity into polymer membranes was determined from the immersion/weight gain experiments. Permeability coefficients were also calculated from the diffusion and sorption data. A temperature dependence of sorption and transport was also investigated to estimate the activation parameters. The experimental results and computed quantities were used to study the type of transport mechanism and the nature of polymer‐solvent interactions.
Effects of the t‐butyl substituent on the miscibility of polyarylates with polyamides
Authors: Dean B. D. , Harris J. E. 
Published: April 2003

AbstractAmorphous polyarylates derived from 12–50 mol % of a t‐butyl‐substituted diacid, e.g., 5‐t‐butylisophthalic acid, exhibit miscibility with the amorphous phase of polyamides having aromatic and aliphatic character. Equally critical to blend miscibility is the aliphatic/aromatic carbon atom ratio (exclusive of the amide functionality) of the polyamide. An aliphatic/aromatic carbon atom ratio (α) greater than 1.4 but less than 2.5 is necessary. © 1992 John Wiley & Sons, Inc.
Use of continuous viscometer and light scattering detectors in characterization of polyolefins: Comparisons of data from individual and combined detectors
Authors: Pang Simon , Rudin Alfred 
Published: April 2003

AbstractMolecular weights of polyethylenes have been characterized using differential refractometer (DRI), continuous viscometer (CV), and low‐angle laser light (LALLS) detection. In normal operation with the latter two detectors, the DRI is also employed as a concentration detector. The intrinsic viscosity of the whole polymer can be derived from the CV without use of a DRI concentration detector. If one calibrates the size exclusion chromatography (SEC) columns using the CV detector, it is possible to use this universal calibration relation and the CV detector to calculate number average molecular weight (Mn) of the polymer. Weight average molecular weight (Mw) of the sample can be calculated using data from the LALLS alone, without reference to the DRI. These variations of the analysis were tested and the advantages and limitations of the different detectors were compared using standard reference polyethylene samples in solution in 1,2,4‐trichlorobenzene at 145°C. © 1992 John Wiley & Sons, Inc.
Electrodeposition properties of self‐crosslinking epoxy–amine cationic resin modified by polycaprolactone diol
Authors: Yang Chin‐Ping , Ting Chih‐Yang 
Published: April 2003

AbstractA self‐crosslinking polycaprolactone diol (PCD)‐modified epoxy–amine adduct was prepared by first synthesizing the PCD‐modified epoxy resin from diglycidyl ether of bisphenol A (DGEBA), PCD and bisphenol A (BPA), then reacting the partially pendant hydroxyl groups of this modified resin with 2‐ethylhexanol half‐blocked with toluene diisocyanate (2‐EH half‐blocked TDI), and finally reacting the terminal epoxy groups with secondary amines such as N‐methyl ethanol amine (MEA) and di(2‐methylisobutylketimino‐ethyl)amine (DKI). This epoxy–amine adduct was neutralized by acetic acid and could be dispersed in deionized water to form a stable emulsion, which could be used for the electrodeposition coating. The effects of solid content, pH value, solvent content of the emulsion, bath temperature, and applied voltage on the deposition yield and the throwing power of the resin were investigated. Meanwhile, the optimum crosslinking condition of the deposition film was also studied. It was found that the electrodeposition properties of the emulsion derived from the modified epoxy resin are superior to those of emulsion derived from the unmodified DGEBA epoxy resin.
Rheology of rigid–flexible liquid crystalline polymer/poly(methyl methacrylate) blends
Authors: Schild H. G. , Kolb E. S. , Gaudiana R. A. , Chiang Y. , Schwarzel W. C. 
Published: April 2003

AbstractThe random liquid crystalline copolymer poly(4,4′‐biphenylene azelate)‐co‐(2‐methyl‐1,4‐phenylene azelate), synthesized by condensation polymerization, was found to be soluble in chloroform and methylene chloride. DSC, rheology, and optical microscopy indicated that this LCP broadly melts at ca. 160°C to a weakly birefringent melt that becomes isotropic at approximately 180°C. DSC and optical microscopy of blends with poly(methyl methacrylate) (PMMA) at wLCP = 0.06, 0.16, 0.34, and 0.69, indicated little compatibility between the polymers at middle compositions. Dynamic and steady shear flow rheological measurements, using cone/plate geometry, showed the PMMA‐rich (6 wt % LCP) and LCP‐rich (69 wt % LCP) blends to be essentially homogeneous, and dominated by the properties of the major component. However, at 16 wt % and 34 wt %, the resulting phase separation led to lower dynamic moduli (than either LCP or PMMA separately), and increased shear thinning. This behavior supports the notion that the LCP acts as a lubricant by promoting the flow of the non‐LCP. The results reported in this article show that these rheological effects, which were previously observed in blends of insoluble, rigid LCPs and engineering thermoplastics, still exist with a much less rodlike LCP mixed with a commodity polymer.
Synthesis and photoconductivity study of phthalocyanine polymers. I. PAA–CuPc(NO2)2
Authors: Chen Hongzheng , Wang Mang , Feng Linxian , Shen Xuebin , Yang Shilin 
Published: April 2003

AbstractCu–dinitro–diamino phthalocyanine was synthesized and converted to the diazonium salt. Polyacrylamide bonded CuPc(NO2)2 [PAA–CuPc(NO2)2] (I) was synthesized by hot polymerization of acrylamide and this diazonium salt. Polymer(I) is water soluble and contains about 7 mol % CuPc(NO2)2 rings, which are covalently bonded to PAA. Polymer(I) shows good photoconductivity, which is much better than that of the corresponding phthalocyanine monomers. By doping with iodine (I2), the photosensitivity of polymer(I) is increased, which through fluorescence analysis is explained by the fact that a charge–transfer complex (CTC) of polymer(I) with I2 is formed. The influence of interface layer (IFL) and charge–transportation material (CTM) on the photoconductivity of polymer(I) were also studied.
Chemical modifications of insoluble polystyrene derivatives
Authors: Migonney V. , Lacroix M. D. , Douzon C. , Jozefowicz M. 
Published: April 2003

AbstractThe development of biospecific polymeric biomaterials requires new methods of chemical treatment that may be achieved whatever the involved polymeric surface without any degradation of the macromolecular structure. To check whether substitution of polymeric surfaces by epoxy groups could be a suitable way of synthesis to reach this goal, functionalization of polystyrene by epoxy groups was carried out. The respective reactions of carboxylic acids, alcohols, aldehydes, hydrochloric and sulfuric acid, and benzylamines have been extensively studied and suitable characterization has been performed on the respective polystyrene derivatives using infrared spectroscopy, elemental analysis, argentimetric titration, and acidimetric titration. In addition, a method of titration of the epoxy groups' content of insoluble functionalized polymers has been developed by the use of 14C‐labeled benzylamine.