bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thermal studies on brominated atactic polypropylene
Authors: Mukherjee A. K. , Mohan Anita 
Published: April 2003

AbstractThermal behavior of brominated atactic polypropylene (BAPP), obtained by thermal bromination of atactic polypropylene (APP), was evaluated by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). It was found that the initial decomposition temperature (IDT) and char yield increase with the increase in bromine content while integral procedural decomposition temperature (IPDT) showed a decreasing trend. A comparative study of these value in inert and oxidative atmospheres has been made. DTA study shows that onset decomposition temperature (ODT) and glass transition temperature (Tg) increase with the increase in degree of bromination. The possible reasons for the occurring phenomena have been discussed.
Photosynthesis and application of polyfunctional poly(n‐butyl acrylate) elastomers for use in epoxy resin toughening
Authors: Wang Hong‐Bing , Li Shan‐Jun , Ye Jin‐Yong 
Published: April 2003

AbstractMedium molecular weight, novel polyfunctional elastomers, namely epoxy groups on poly(n‐butylacrylate) (ETPnBA) and carboxyl groups on poly(n‐butylacrylate) (CTPnBA) were photosynthesized for evaluation as the toughening agents in epoxy resins. The effect of the functionality and kind of functional group of the elastomers upon the toughening of epoxy resins modified with these rubbery copolymers as a second phase was investigated by tensile tests, impact test, and electron microscopy. It was found that there exists an optimum functionality of elastomers for maximum impact resistance in epoxy groups (ETPnBA) and carboxyl groups (CTPnBA) copolymer‐modified systems. Studies on morphology of the modified epoxy resin system indicated that the better toughening effects of multiple distribution of particle sizes. The aggregation of rubber particles occurring in carboxyl group CTPnBA modified epoxy resin caused a loss of toughness.
The interfacial polycarbonate reactions. I. Defining the critical process parameters
Authors: Gu Jen‐Tau , Wang Chun‐Shan 
Published: April 2003

AbstractPolycarbonate is prepared by the interfacial phosgenation and polycondensation of bisphenol A (BPA) in methylene chloride with caustic using triethylamine as a catalyst. In a typical batch reactor, where phosgenation and oligomerization proceed simultaneously, the critical process parameters are intermingled and are difficult to determine. Therefore, a semicontinuous process consisting of a series of static mixers for continuous phosgenation, followed by a batch reactor for oligomerization and polycondensation, was developed for better understanding of the reaction mechanisms. Phosgene hydrolysis was reduced greatly going from a batch to a continuous reactor (excess phosgene was reduced from 30 to 5%). Variables which influence the composition of intermediates are linear velocity, organic to aqueous volume ratio, PH (BPA to NaOH ratio), and phosgene to BPA ratio. These variables also affect BPA conversion, amount of phosgene hydrolysis, terminator capping efficiency, molecular weight, and molecular weight distribution of the resulted polycarbonate. Oligomerization takes place at the interface, and monochloroformates (HO‐Bn‐OCOCI) which contain both hydrophilic and lipophilic end groups, stay at the interface and, hence, react preferentially. Oligomers are analyzed by a newly developed HPLC technique.
Polymerization of acrylamide initiated with electrogenerated cerium (IV) in the presence of EDTA
Authors: Saraç A. Sezai , Erbil Candan , Soydan A. Bahattin 
Published: April 2003

AbstractPolymerization of acrylamide was carried out with cerium (IV)‐EDTA redox initiator system with and without electrolysis. The effect of temperature, time, cerium (IV), and EDTA concentrations on the polymerization yield and molecular weight were studied and compared with electrolytic conditions. At low concentrations of cerium (IV) the electrolytic method continuously supplying Ce (IV) from Ce (III) has an advantage over the nonelectrolytic method for which polymerization did not occur under these conditions. A possible polymerization mechanism is suggested.
The determination of the pore structural parameters of isoporous resins by inverse GPC
Authors: Wang Anyou , Yan Juntan , Xu Rongnan 
Published: April 2003

AbstractThe swollen pore structure of a series of microporous isoporous resins (7.4–140 Å) are investigated with inverse GPC, n‐alkylbenzenes and linear polystyrenes being used as probe molecules. The results indicated that, with the lowering of crosslinking degree of isoporous resins, the average pore diameter increased and the pore distribution curve broadened. All pore volume distribution obeyed a log‐normal distribution. Based on the linear regression method, the experimental data were fitted to a monotonously declining exponential function and a normal distribution function by a computer, and some important structural parameters such as average pore diameter, pore volume distribution, specific surface area, etc. were obtained. The specific surface area of swollen gels were found much greater than those in the dry state measured by N2 adsorption.
Cellulose nitrate–poly(vinyl chloride‐co‐vinyl acetate)–polyurethane ternary IPNs: FT‐IR and morphological studies
Authors: Natchimuthu N. , Rajalingam P. , Radhakrishnan Ganga 
Published: April 2003

AbstractTernary semi‐IPNs of nitrocellulose, poly(vinyl chloride‐co‐vinyl acetate), and polyurethanes have been synthesized and characterized by FT‐IR, SEM, and differential scanning calorimetry. Semi‐IPNs of nitrocellulose‐polyurethanes are found to be incompatible whereas the ternary system consisting of nitrocellulose‐poly(vinyl chloride‐co‐vinyl acetate) and polyurethanes is partially compatible. Hydrogen bonding interactions are discussed based on the FT‐IR analysis. The tensile strength and percent elongation are interpreted on the basis of the NCO/OH ratio and composition.
Spectroscopic study of polytoluidines in the UV‐visible and IR regions
Authors: Fujita Iwao , Ishiguchi Mitsuharu , Shiota Hiroshi , Danjō Takeshi , Kosai Kouichi 
Published: April 2003

AbstractElectropolymerization of o‐toluidine(o‐methylaniline) and m‐toluidine was carried out in acidic aqueous solution, and UV‐visible and IR spectra of the resulting polymer films were obtained at various electric potentials and pHs. In Na2SO4 aqueous solution, poly(o‐toluidine) gave considerably different UV‐visible spectra from polyaniline, whereas, in HCl (pH ∼ 0), the spectra of poly(o‐toluidine) changed in the same way as polyaniline when the potential was varied. This spectral change depended also on counterion. This suggests that the intermediate state (radical cation) of poly(o‐toluidine) is unstable in a neutral solution especially when a large counter ion exists, which is contrast to polyaniline. The dependency of the FT‐IR spectra of poly(o‐toluidine) on the potential and pH supported also the above result of UV‐visible spectra. From both UV‐visible and IR spectra under various conditions, it was found that o‐toluidine and m‐toluidine give the same polymer.
Preparation of colloidal silver using various reductants in the presence of copolymers of vinyl alcohol‐N‐vinyl pyrrolidone
Authors: Esumi Kunio , Ishizuki Norio , Torigoe Kanjiro , Nakamura Hideuki , Meguro Kenjiro 
Published: April 2003

AbstractColloidal silver was prepared using various reductants such as hydrazine, ascorbic acid, ribose, and hydrogen in aqueous solution in the presence of copolymers of vinyl alcohol‐N‐vinyl pyrrolidone. The average particle size of colloidal silver decreased with increasing amount of copolymers added. The reduction by hydrogen provided smaller silver particles compared with the other reductants. The stability of colloidal silver against AlCl3 increased with increasing amount of copolymers added.
Alumina–carbon composite fibers from poly[(acyloxy)aloxane]s
Authors: Yamane Hideki , Hashimoto Koichi , Kimura Yoshiharu , Kitao Toshio 
Published: April 2003

AbstractThe alumina–carbon composite fibers were obtained from poly[(acyloxy)aloxane] (PAA) with 3‐ethoxypropanoic (EPA) and m‐anisic acids (m‐AA) legands. This preceramic polymer can be dissolved in p‐xylene‐methanol‐EPA mixed solvent, and the concentrated solution exhibited an excellent spinnability. During the pyrolysis and sintering processes, aliphatic carboxylate in the side groups was easily decomposed and eliminated. The aromatic carboxylate, however, seems to be converted and migrated to a carbon domain in the alumina matrix into which aloxane repetition was converted. The fibers pyrolyzed up to 800 and 1000°C have electrical conductivities that monotonically increase with increasing temperature. The fiber pyrolyzed up to 1200°C showed the electrical conductivity in a rather complicated manner.
Morphology and properties of polyurethane/poly(methyl methacrylate) interpenetrating polymer networks by Co60–γ ray
Authors: Wang Geng‐Chao , Cui Hai‐Wei , Fang Bin , Zhang Zhi‐Ping 
Published: April 2003

AbstractPU/PMMA IPNs were first synthesized using Co60–γ radiation. The morphology, glass transition behavior, and mechanical properties of the formed IPNs have been studied by TEM, DSC, and electron tensile testing machine. The TEM micrographs and the results of DSC showed that Co60–γ radiation was effective for obtaining small volume sizes of phase domains in IPNs. The structure with two continuous phases occurs in the content range of 40% to 70% PU. The ability of interpenetration enhanced with increasing the content of the crosslinking agents. The mechanical properties of IPNs reflected very good synergistic behavior.
Copolymers of N‐vinylcarbazole with monomers containing carboxylic acid groups or carboxylic anhydride groups. I
Authors: Wainwright M. , Griffiths J. , Guthrie J. T. , Gates A. P. , Murray D. E. 
Published: April 2003

AbstractN‐Vinylcarbazole has been copolymerized with olefinic monomers possessing carboxylic acid or carboxylic anhydride functionality to yield copolymers with associated solubility in aqueous alkaline media. The copolymers were prepared to be part of a photoconductive lithographic printing plate assembly. The composition of the copolymers and the reactivity ratios have been evaluated. Copolymerization mechanisms are discussed. Alkali solubility has been measured in terms of the decoating speeds of films of the copolymers from aluminum plates. The major aim of producing an alkali‐soluble copolymer that retained the photoconductive properties associated with poly(N‐vinylcarbazole) was achieved in part.
Effect of iron oxides on the thermal degradation of natural rubber from Manihot glaziovii
Authors: Barros Glaucione Gomes De , Ricardo NáGila Maria Pontes , Vieira Vicente Walmick 
Published: April 2003

AbstractThe effect of iron oxides particles mixed in natural rubber (NR) or aged natural rubber (ANR) from Manihot glaziovii were investigated. IR spectroscopy showed that α‐Fe2O3 inhibits or retards the thermal degradation (200°C) of ANR, but it does not inhibit or retard the thermal degradation of NR. A retardation effect is observed using iron (III) oxide in both ANR and NR. Using both oxides, longer autoxidation induction periods of ANR and NR are observed (150°C). The periods were extended for a higher content of rubber hydroperoxide concentration. The inhibition or retardation of autoxidation using Fe3O4 in both ANR and NR is not evident. We suggest an interaction between hydroxyl groups of hydroperoxide, mainly present in aged natural rubber, and the iron oxide surface.
Synthesis and study of some newer polyamides for semipermeable membrane
Authors: Shukla J. S. , Dixit S. K. 
Published: April 2003

AbstractA series of novel polyamides was prepared by low temperature solution polycondensation of N‐(p/m‐aminobenzoyl aminoacetyl)‐N'‐(4/3‐aminobenzoyl) hydrazine with different diacid chlorides in dry N,N‐Dimethylacetamide (DMAC). The properties of the polyamides for membrane processing were studied with the help of infrared spectra, inherent viscosity, differential thermal, and thermogravimetric analysis. The inherent viscosities were measured in concentrated sulfuric acid at 25±5°C and were in the range of 0.35–0.89 dL/g. The thermogravimetric data in air indicate that the initial decomposition temperature was in the range of 175–200°C. The polymer melt temperature (Tm) and glass transition temperature (Tg) were in the range of 230–450°C and 153.3–300°C, respectively.
Charge transfer copolymerization and properties of isopropyl methacrylate with acrylonitrile and methacrylonitrile
Authors: Bixamaiah B. , Rao P. Raghunath , Sundaram E. V. 
Published: April 2003

AbstractIsopropyl methacrylate (IPMA) with Acrylonitrile (AN) and Methacrylonitrile (MAN) copolymers of different copositions were prepared at 60°C and 80°C, respectively, using a mixture of n‐Butylamine (nBA) and carbon tetrachloride (CCl4) in dimethyl sulphoxide (DMSO) as a charge transfer (CT) initiator. The percentage composition of the copolymers was established by elemental analysis. The copolymerization reactivity ratios were computed by the Kelen–Tudos method. In both the systems, IPMA was found to be more reactive; the copolymers sequence was random in nature. The copolymers were characterized by IR, 1H‐NMR, 13C‐NMR spectroscopy and intrinsic viscosity measurements in dimethyl formamide (DMF) at 30±0.1°C. The thermal behavior of the AN‐IPMA copolymers was studied by thermogravimetry (TG) in air. The thermal stability increased, with increasing AN content in the copolymer chain. The solubility parameter of AN‐IPMA copolymer was evaluated by studying the intrinsic viscosity in different solvents. The solubility parameter of the copolymer was found to be 9.7 (cal/cc)1/2.
Bead‐spring macromolecules: The kinetic contribution to the total stress
Authors: Grisafi S. 
Published: April 2003

AbstractUsing complete phase space distributions, this analysis predicts an isotropic kinetic contribution to the total stress for both the solvent and polymer. The solvent's contribution depends on the polymer's intramolecular potential energy, as well as the intermolecular potential between the solvent and polymer. The analysis questions whether single molecule distributions are capable of investigating the possibility of anisotropic kinetic distributions. The analysis uses the peculiar velocity fields in lieu of modeling molecular collisions.
Study on organosilicon positive resist. I. Syntheses and characterization of silsesquioxane, siloxane, and silmethylene polymers with phenolic hydroxy groups
Authors: Sugiyama Hisashi , Inoue Takashi , Nate Kazuo 
Published: April 2003

AbstractSilsesquioxane, siloxane, and silmethylene polymers with phenolic hydroxy groups were prepared in order to obtain alkali‐soluble organosilicon polymers. These polymers have structures in which the phenol moieties are separated by one carbon from the silicon. The hydroxy groups were protected as methoxy groups in polymerization processes, then were changed into hydroxy groups by a reaction with trimethylsilyl iodide followed by alcoholysis. In the course of discussion on the characteristics of these polymers, silsesquioxane with phenolic hydroxy groups is found to possess excellent properties for matrix resins of alkalidevelopable organosilicon resists, such as O2RIE resistance and heat resistance.
Melt‐polymerized aliphatic‐aromatic copolyamides. I. Melting points of nylon 66 copolymerized with aromatic diamines and terephthalic acid
Authors: Kudo K. , Suguie T. , Hirami M. 
Published: April 2003

AbstractMeasurements of melting points were made for melt‐polymerized aliphatic‐aromatic copolyamides; (i) N66PT, (ii) N66CT, and (iii) N66ST, i.e., nylon 66 [poly(hexamethylene adpamide)] copolymerized with three kinds of aromatic diamines, p‐phenylenediamine (P), bis (p‐aminophenyl) methane (C), and bis (p‐aminophenyl) sulfone (S), and terephthalic acid (T). As the mole fraction of copolymerized component n1, increases in the case of (ii) or (iii), the melting point decreases uniformly according to the relationship of Flory. In the case of (i), the melting point first decreases and then begins to increase after passing a minimum at n1 ≃ 0.2. A preliminary WAXD (wide‐angle X‐ray diffraction) study on N66PT crystals shows that the basal plane of the crystal lattice shifts from that of nylon 66 toward hexagonal packing with the increase of n1. It was suggested that the formation of mixed crystals for a series of N66PT will be attributed to their melting point behavior.
Effects of types of fillers on the molecular relaxation characteristics, dynamic mechanical, and physical properties of rubber vulcanizates
Authors: Dutta Naba K. , Tripathy D. K. 
Published: April 2003

AbstractThe dynamic mechanical, and physical properties of bromobutyl rubber were investigated to determine the effect of particle size and of the structure of carbon black and silica. Filler loading was so adjusted that all the experimental compositions had the same hardness level. The results indicate that the type and loading of filler have no significant effect on the molecular relaxation transition. However, elastomer having a desirable storage modulus with low sensitivity to temperature change can be developed using filler with smaller particle size. Higher elongation at break, and better tensile strength, energy density at break, and fatigue life could be obtained by using finer particle or high structure black than with the low structure and higher particle size black. Finer particle size filler loaded systems exhibit pronounced strain dependence, higher thixotropic change, and delayed recovery in dynamic mechanical properties compared to that exhibited by large particle size filler.
Polymer concrete and polymer mortar using resins based on recycled poly(ethylene terephthalate)
Authors: Rebeiz K. S. , Fowler D. W. , Paul D. R. 
Published: April 2003

AbstractFundamental properties of polymer concrete (PC) and polymer mortar (PM) made from unsaturated polyester resins based on recycled poly(ethylene terephthalate), PET, are described. Mechanical properties investigated include strength, modulus of elasticity, ductility index, Poisson's ratio, coefficient of thermal expansion, shrinkage, and exotherm. Durability properties include chemical resistance, water absorption, sand‐blast resistance, and thermal cycles of thin overlays on portland cement concrete slabs. Resins based on recycled PET offer the possibility of a lower source cost for forming useful PC and PM (PC/PM) based products. The recycling of PET in PC and PM would also help alleviate an environmental problem and save energy.
Grafting of 2‐(dimethlamino) ethyl methacrylate onto gamma irradiated polypropylene fabric
Authors: Gawish S. M. , Kantouch A. , El Naggar A. M. , Mosleh S. 
Published: April 2003

AbstractPolypropylene fabric was gamma pre‐irradiated at doses of 1,2 and 3 Mrads. The irradiated fabric was grafted with an aqueous solution of 2‐(dimethylamino) ethyl methacrylate. The graft yield was studied as a function of the different variable conditions such as storage time, monomer concentration (10–40%), reaction time, and temperature (50, 70, 100°C). The grafted polypropylene was further quaternized with dimethyl sulphate or monochloroacetic acid. The grafted and quarternized fabrics were dyed with an acid dye. The fixation properties of the dyed samples were determined by DMF extraction. The moisture regain and mechanical properties were also measured.
Reverse osmosis separation of binary organic mixtures using cellulose acetate butyrate and aromatic polyamide membranes
Authors: Fang Yi , Sourirajan S. , Matsuura Takeshi 
Published: April 2003

AbstractA systematic investigation has been conducted to demonstrate applicability of reverse osmosis (RO) fractionation of organic liquid mixtures by laboratory‐prepared cellulose acetate butyrate (CAB) and aromatic polyamid (PA) membranes. The determination of preferential sorption was also conducted by using liquid chromatography technique. It was found that reverse osmosis was applicable to the fractionation of organic liquid mixtures. It was also found that the component of the binary mixture that is enriched in the membrane permeate can be predicted by considering the preferential sorption and Stokes' radius for each constituent of the feed mixtre.
Dilute solution properties of cationic poly(dimethyl sulfate quaternized dimethylaminoethyl methacrylate)
Authors: Liaw Der‐Jang , Shiau Saa‐Jen , Lee Kueir‐Rarn 
Published: April 2003

AbstractThe dilute solution properties of a cationic polyelectrolyte, poly(dimethyl sulfate quaternized dimethylaminoethyl methacrylate) [poly(DMAEM · C2H6SO4)], are studied by measurements of intrinsic viscosity, degree of binding, and flocculation application. The intrinsic viscosity of this polyelectrolyte is related to the type and concentration of added salt. The intrinsic viscosity behavior for cationic polyelectrolyte resulting from the electrostatic repulsive force of the polymer chain is contrasted with polyampholyte. The polyelectrolyte in the presence of KCl has a lower degree of binding, indicating that the proton ion (H+) is relatively difficult to bind to the CH3SO4− at the polymer end. The polymerization of DMAEM · C2H6SO4 in 0.5M KCl aqueous solution proceeded more easily than that of DMAEM · C2H6SO4 in pure water. The polymerization rate of DMAEM · C2H6SO4 is found to pass through an extreme value as a function of pH. Optimum flocculation, corresponding to the complete removal of turbidity in the supernatant, is achieved. Beyond the optimum flocculation, high polymer dosages redisperse the bentonite suspensions.
Finely porous models and radially averaged friction factors
Authors: Tremblay A. Y. 
Published: April 2003

AbstractThe finely porous (FPM) and modified finely porous (MD‐FPM) models were used to generate sieving curves for the permeation of polyethylene glycol solutions through a nanofiltration membrane. The curves were calculated at five different operating pressures. Both models use Faxen's equation to calculate the friction factor b−1. Faxen's equation represents the friction between a solute molecule translating along the centerline of a cylindrical pore and the pore wall. The resulting sieving curves were quite different from the typical sigmoidal curves found in ultrafiltration. The departure from this typical shape, was considerable at the lower pressures used in nanofiltration and was less pronounced at the higher pressures found in reverse osmosis. Reasonable sieving curves were obtained when Faxen's equation was radially averaged. Differences in PEG separation of 22 to 32% were obtained between the averaged and the centerline approaches. The partition coefficient K was predicted, for sucrose, raffinose, and NaCl. The use of centerline values of the friction factor led to the overestimation of solute rejection by a factor of 1.24 to 3.11. Finally, in both the FPM and MD‐FPM models, centerline correlations of the friction factor, b−1, must be multiplied by (1−λ)2 in order to be consistent with other averaged quantities.
Theoretical and experimental conversion in the curing of unsaturated polyester resins with styrene as a crosslinking agent
Authors: Ramis X. , Salla J. M. 
Published: April 2003

AbstractThe reaction of unsaturated polyester resin is a free radical copolymerization between the styrene monomer and the unsaturated polyester. Depending on the temperature and other processing conditions, some of the reacting molecular species remain, after curing, in the form of residual monomer and soluble polymer that do not contribute to the network structure. By means of DSC and gel permeation chromatography (G.P.C.) techniques, we have investigated the differences between theoretical and experimental reaction heats of unsaturated polyester samples with different styrene/polyester ratios, the residual species formed, and the conversion of reactive groups.