bluuebunny/crossref_metadata_2025 huggingface dataset:
Compatibility of poly(2,6‐dimethyl‐1,4‐phenylene oxide)/poly(fluorostyrene‐co‐chlorostyrene) blends
Authors: Vuković Radivoje , Kurešević Vjera , Šegudović Nikola , Karasz Frank E. , Macknight W. J.
Published: April 2003

The compatibility of poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) with random copolymers of ortho‐ and para‐fluorostyrene as well as with ortho‐ and para‐chlorostyrene of various copolymer compositions was examined. The compatibility was studied by DSC and visual observation of film clarity. It was found that copolymers of ortho‐fluorostyrene with para‐chlorostyrene containing 15–74 mol % p‐CIS are compatible with PPO in all proportions. Compatibility of the PPO/poly‐(ortho‐fluorostyrene‐co‐ortho‐chlorostyrene) system was observed for copolymers containing between 15 and 36 mol % ortho‐chlorostyrene. Copolymers of para‐fluorostyrene with para‐chlorostyrene, as well as copolymers of para‐fluorostyrene with ortho‐chlorostyrene appear to be incompatible with PPO at 210°C.
Reinforcement as a hindrance in the disentanglement of unknotted chains
Authors: Macarthur A. , Stephens H. L.
Published: April 2003

Observation of many tangles supports a loop mechanism of entanglement in macroscopic systems. The untangling of an unknotted tangled cord gives curves resembling the behavior under constant stress of an uncrosslinked elastomer. Reinforcement as a function of filler loading has been calculated for a model system consisting of uniform spherical particles in an unknotted tangled matrix. These calculated curves show the maxima found in real systems. Reinforcement also increases with decreasing particle size. The effect on the entanglement of porous particles and particles forming surface attachments with the polymer have been considered. The maximum in the calculated reinforcement curve shifts toward higher filler loading with increasing surface activity. This shift is independent of particle size and suggests a method for assessing the relative effectiveness of different coupling agents.
Glass transitions of styrene/α‐methylstyrene statistical copolymers and of their blends with PPO® resin
Authors: Shultz A. R. , Young A. L.
Published: April 2003

The glass transition temperatures (Tg) and specific heat increments (ΔCp) at Tg of S/AMS statistical copolymers having weight fractions AMS of 0.00, 0.09, 0.17, 0.26, 0.36, and 0.44 are (by DSC) 380.0 (0.280), 384.2 (0.275), 388.8 (0.284), 391.5 (0.275), 398.3 (0.272), and 405.9 (0.27) °K (J·g− ·deg−), respectively. The Tg (ΔCp) for the PPO resin are 492.2 (0.221). The glass transitions of P(S/AMS) (1) + PPO resin (2) blends having w2 = 0.25, 0.50, and 0.75 were also measured. Examination of the copolymer and blend Tg vs. composition data indicates that a relation recently proposed by Couchman gives a somewhat better approximation than the simple Fox relation. However, the nonadjustable k = ΔCp2/ΔCp1 constant in the Couchman relation must be replaced by a smaller empirical k to give a true match of calculated to observed Tg.
Intumescent flame retardants for polymers. I. The poly(acrylonitrile)–ammonium polyphosphate–hexabromocyclododecane system
Authors: Ballistreri A. , Montaudo G. , Puglisi C. , Scamporrino E. , Vitalini D.
Published: April 2003

The influence of ammonium polyphosphate (APP) and hexabromocyclododecane (HBCD) as flame retardant (FR) on poly(acrylonitrile) (PAN) has been examined. The APP–HBCD system behaves as an intumescent flame retardant (IFR) formulation, APP being the char‐forming agent and HBCD the blowing agent. A negligible gas‐phase mode of action was ascertained for HBCD with this substrate. A synergism between the two FR agents was observed, corresponding to about 50% increased efficacy with respect to the separate effects of the two components. Thermogravimetry (TG), oxygen index (OI), nitrous oxide index (NOI) experiments and phosphorous residue measurements were performed to substantiate the conclusion that a conclusion that a condensed phase mechanism of action accounts for all the facts observed.
Effects of sucrose on the rheological behavior of wheat starch pastes
Authors: Cheer R. L. , Lelievre J.
Published: April 2003

The rheological properties of starch–water–sucrose pastes have been determined under steady and oscillatory shear conditions. The results show that the effect of sucrose at concentrations of less than about 20% w/w is to increase the apparent viscosity, yield stress, dynamic viscosity, and dynamic rigidity. At higher surose concentrations the yield stress and dynamic rigidity tend to zero while values of the dynamic viscosity and apparent viscosity are reduced compared with controls. Sucrose causes the dispersed gel particles in pastes to change volume, and it is suggested that this is one of the factors responsible for the observed effects of sucrose on rheological behavior.
Birefringence of injection‐molded glassy polymers during relaxation and recovery
Authors: Qayyum M. M. , White J. R.
Published: April 2003

Birefringence measurements have been made on six glassy polymers during stress–relaxation and recovery experiments at temperatures below Tg. Of the six polymers tested only one pair, poly(ethylene terephthalate) and a glassy polyamide (“Trogamid”), show a strong mutual resemblance in the behavior of birefringence under these conditions. The results are discussed with reference to molecular structure, and, although detailed interpretations are not offered, it is observed that the behavior is less complex for polymers which possess their most polarizable groups in the main chain or attached rigidly to it than for those polymers having polarizable side groups with relaxations which do not involve the main chain. All six polymers have been tested in injection‐molded form, and the possible consequences of this are considered. The major differences observed to occur between the different materials do not appear to be related to processing, however, and some results obtained using specimens prepared in other ways are also presented to illustrate this.
Analysis of thermal oligomerization mechanism of styrene by field desorption mass spectrometry
Authors: Saito J. , Teramae N. , Hara J. , Toda S. , Tanaka S.
Published: April 2003

Field desorption mass spectra of normal and deuterated styrene oligomers synthesized in several alkylbenzenes were measured. Analysis of the mechanism of thermal oligomerization was carried out by identifying the molecular species in the reaction system using field desorption mass spectra. As a result, the existence of several kinds of molecular species was confirmed. The minor molecular species originated from dissolved oxygen, from the cleavage of solvent radicals to which oxygen was attached, or from H–D exchange in the oligomerization of deuterated styrene. The major molecular species originated from radical telomerization of solvents and styrene dimers, from the recombination termination reaction, and from the cage reaction between initiating radicals. Field desorption mass spectrometry was found to be useful for analyzing the mechanism of styrene oligomerization as well as characterizing the oligomers.
Grafting of polyesters onto carbon black. III. Polymerization of β‐propiolactone initiated by quaternary ammonium carboxylate groups on the surface of carbon black
Authors: Tsubokawa Norio , Funaki Akira , Sone Yasuo
Published: April 2003

By use of carbon black containing quaternary ammonium carboxylate (COO−N+R4) groups as catalyst, the anionic ring opening polymerization of β‐propiolactone (PL) was carried out at 50°C. Although carbon black itself was unable to initiate the polymerization of PL, carbon black containing COO−N+R4 groups, which was prepared by the reaction of carboxyl groups with corresponding quaternary ammonium hydroxide, was found to be able to initiate the polymerization. The carbon black obtained from the polymerization gave a stable colloidal dispersion in an organic solvent, and it was confirmed that the polyester formed was effectively grafted onto the surface. In addition, the effect of quaternary ammonium countercation on the polymerization was investigated.
Rheology‐processing‐property relationships in tubular blown film extrusion. II. Low‐pressure low‐density polyethylene
Authors: Kwack Tae Hoon , Han Chang Dae
Published: April 2003

An experimental investigation was undertaken to establish rheology‐processing‐property relationships in the tubular blown film extrusion of low‐pressure low‐density polyethylene (LP‐LDPE). For the study, three commercial LP‐LDPE resins, each from a different resin manufacturer, were used in producing tubular films, by employing the apparatus described in Paper I of this series. Both molecular and rheological characterizations of the resin were conducted, enabling us to interpret the tubular film blowing characteristics of the resins. Correlations were obtained between the processing variables (namely, blowup and takeup ratios) and the tensile properties of the films. The tubular film blowing characteristics of LP‐LDPE and HP‐LDPE resins are compared. Differences in the rheological properties (namely, elongational viscosity) of the two types of resin are used in explaining the experimentally observed differences in their tubular film blowability.
Relationships between the synthesis conditions and the characteristics of anion exchangers
Authors: Luca Cornelia , Poinescu Ig. , Avram Ecaterina , Ioanid Aurelia , Petrariu I. , Carpov A.
Published: April 2003

Several macroporous styrene–divinylbenzene copolymers were prepared using different diluents. The copolymers were chloromethylated with monochlor methyl ether and aminated with N,N‐dimethyl‐2‐hydroxyethylamine in order to perform strongly basic anion exchanger, type II. It was established that the network morphology of anion exchanger determines its ion‐exchange rate. It was, also established, by means of transmission electron microscopy, that chloromethylation reaction led to the morphological changes in the macromolecular network of the copolymers.
Semi‐ and fully interpenetrating polymer networks based on polyurethane–polyacrylate systems. II. Polyurethane–poly(methyl acrylate) semi‐1‐interpenetrating polymer networks
Authors: Hourston D. J. , Zia Y.
Published: April 2003

A series of semi‐1‐IPNs based on polyurethane networks and poly(methyl acrylate) were prepared, and their properties and morphologies investigated. All the materials showed substantial phase separation, but the phase sizes were orders of magnitude smaller than those observed for blends of the same linear polymers. The effects of the isocyanate/hydroxyl ratio used in the preparation of the polyurethane, of the molecular weight of the linear polymethyl acrylate component, of the overall composition, and of the molecular weight between crosslinks in the polyurethane networks were investigated. Stress‐relaxation experiments were conducted over a range of temperatures and master curves were produced for both components of the semi‐1‐IPNs and for a semi‐1‐IPN containing 40 wt% polyurethane. It was found that both the components obeyed a WLF type of equation, but that the semi‐1‐IPN only showed this type of behavior over a limited temperature range. Several reinforcement theories were applied to experimental dynamic storage modulus data. The closest fit was given by the Davies equation and by the logarithmic rule of mixing. By changing the exponent in the Davies equation to 1/10, a close fit was found. Application of a modified Takayanagi model indicated that these semi‐1‐IPNs showed some dual phase continuity when the poly(methyl acrylate) composition was relatively high.
Diffusion of dyes in adsorptive dyeing
Authors: Kumazawa Hidehiro , Sada Eizo , Ando Tetsuo
Published: April 2003

The concentration dependence derived from both steady‐state permeation and unsteady‐state dyeing runs for a system of acid dye C. I. Acid Blue 182‐nylon 6 film was analyzed in terms of parallel diffusion with simultaneous multimodal adsorption proposed in the previous paper. The present dyeing process was governed by the surface diffusion incorporating three kinds of Langmuirean adsorption modes. The concentration dependence of the diffusion coefficient of the cationic dye C. I. Basic Red 22 in the anionically modified polyester fiber Dilana measured by Ostrowska et al. [B. Ostrowska, A. Narebska, and H. Krzystek, J. Appl. Polym. Sci., 26, 463 (1981)] was satisfactorily interpreted by the parallel diffusion incorporating two kinds of Langmuirean adsorption modes.
The effects of degree of mixing on the properties of filled elastomers
Authors: Lee Michael C. H.
Published: April 2003

A new technique has been established for improving the degree of mixing of the filler in an elastomer matrix. This technique includes a unique heating and colling mixing procedure in conjunction with surface modification of the carbon black and proper choices of polymers. The heating cycle is for decreasing the microvoid concentration and for enhancing polymer–filler adhesion. The cooling cycle is for improving the degree of mixing of the filler. Experimental data obtained from several polychloroprene systems strongly substantiate the new mixing technique. The results clearly show that a good degree of mixing obtained using the foregoing mixing technique can indeed enhance the mechanical and permeability properties of filled elastomers.
New aspects in cationization of lignocellulose materials. I. Preparation of lignocellulose materials containing quarternary ammonium groups
Authors: Antal Miroslav , Ebringerová Anna , Šimkovic Ivan
Published: April 2003

TMAHP derivatives were prepared by the reaction of beech sawdust with CHMAC in alkaline medium. The examination of the reaction conditions showed that the most suitable molar ratio was NaOH/CHMAC = 1.8 (1 ml 17.5% NaOH/1 mL 50% CHMAC). At this ratio the maximum degree of substitution expressed by the exchange capacity of 0.35 mmol/g of modified sawdust was obtained by using 1.5–2mL of 50% aqueous solution of CHMAC/g sawdust. The optimal reaction time at 60°C was 2 h. This condition gave yields of modified sawdust above 90% and soluble derivatives mainly consisting of hemicelluloses up to 12%.
New aspects in cationization of lignocellulose materials. II. Distribution of functional groups in lignin, hemicellulose, and cellulose components
Authors: Antal Miroslav , Ebringerová Anna , Šimkovic Ivan
Published: April 2003

The distribution of functional groups in the three main components of beech after alkylation with 3‐chlor‐2‐hydroxypropyltrimethylammoniumchloride (CHMAC) was studied. By fractional extraction of hemicellulose combined with delignification it was found that the three components were substituted to various extents. The exchanging capacity decreased in the following order: hemicellulose, lignin, and cellulose. The obtained degree of substitution is related to the accessibility and reactivity of the individual components in the wood. Hemicellulose, which is substituted the most, can be extracted from modified sawdust with water. This represents a new method of hemicellulose isolation from native plant materials.
Chemical modification of polystyrene. V. Sulfonic acid resins from anhydride substituted polystyrene
Authors: Biswas Mukul , Chatterjee Shakuntala
Published: April 2003

Chemically modified polystyrenes based on the condensation of polystyrene with phthalic anhydride, trimellitic anhydride, and cis‐1,2,3,6‐tetrahydrophthalic anhydride have been processed into sulfonic acid cation exchange resins. The effects of variation of sulfuric acid amount and the temperature of sulfonation on the synthesis and the ion‐exchange capacities of the resins have been established. The resins have finally been characterized with respect to their structures by IR and elemental analysis data. The total ion exchange capacity as well as the salt‐splitting capacity and the pH‐metric titration characteristics of these resins have also been determined. These resins posses better ion‐exchange capacities than the conventional styrene based resins.
Effect of crystallinity on gas permeation in miscible polycarbonate–copolyester blends
Authors: Preston W. E. , Barlow J. W. , Paul D. R.
Published: April 2003

Permeation rates of helium, methane, and carbon dioxide in miscible blends of polycarbonate and a copolyester were measured at 35°C. The permeabilities for semicrystalline blends having copolyester cyrstallinity induced by annealing were compared to fully amorphous blends. Crystallinity caused a slightly greater impedance to carbon dioxide transport than it did for helium or methane. The relative rates of permeation of one gas compared to another, an issue important for membrane separations, varied greatly with blend composition; however, the effect of crystallinity was not large.
Nucleation of PET crystallization by metal hydroxides
Authors: Aharoni Shaul M.
Published: April 2003

PET formulations containing small amounts of nonalkali metal hydroxides were prepared by extrusion from the melt. The efficiency of the hydroxides as nucleating agents was estimated from the elevation of Tcc, the crystallization temperature upon cooling from the melt, normalized for the purpose of comparison to a single convenient Mw (or the corresponding intrinsic viscosity). The results show that metal hydroxides capable of releasing water within the processing temperature interval of PET are effective nucleating agents for the crystallization of the polymer. Hydroxides releasing water out of said interval do not nucleate PET. There are two proposed nucleation mechanisms: (a) a localized severe hydrolysis of PET by the water released in the immediate neighborhood of the hydroxide particles and (b) a localized supercooling of the PET in the vicinity of the particles by the released water. The hydrolyzed PET of sharply reduced molecular weight has a Tcc significantly higher than the Tcc of the unhydrolyzed majority of the polymer. Upon cooling from the melt, and with the possible localized supercooling, the PET in the immediate vicinity of the hydroxide particles crystallizes first, nucleating the rest of the polymer. At present we can not verify whether both mechanisms operate concomitantly and which one of them is dominant.
Radiation vulcanization of natural rubber latex with polyfunctional monomers
Authors: Makuuchi Keizo , Hagiwara Miyuki
Published: April 2003

Natural rubber latex was irradiated with γ‐rays from Co‐60 in the presence of polyfunctional monomers to accelerate crosslinking of rubber molecules. Hydrophobic monomers were more effective in accelerating the vulcanization than were hydrophilic monomers. This was ascribed to high solubility of hydrophobic monomers in rubber particles. Among the hydrophobic monomers, neopentylglycol dimethacrylate (NPG) exhibited the highest efficiency in accelerating the vulcanization. Advantages of using NPG are (1) high colloidal stability of the irradiated latex and (2) high thermal stability of dried rubber film.
Surface wettability of human hair. I. Effect of deposition of polymers and surfactants
Authors: Kamath Y. K. , Dansizer C. J. , Weigmann H.‐D.
Published: April 2003

Monitoring the wetting force exerted on a single fiber while the fiber is slowly and continuously immersed in a liquid and then withdrawn can provide several kinds of information about the physicochemical heterogeneity of the fiber surface. This method for scanning the fiber surface with an appropriate liquid has been found useful for studying the distribution of materials deposited on the surface of human hair to improve hair assembly properties, such as cationic polymers used in hair conditioners. It is shown how wetting force vs. immersion depth curves can reflect not only the average distribution of the material on the surface, but also the degree of uniformity of the deposit; further, wetting force curves for multiple immersions of the same treated fiber indicate the ease of desorption of the surface material. The results for the systems studied, which include mildly oxidized hair and smooth nylon fibers for comparison, show how the relation between the critical surface tension of the fiber and the surface tension of the treating solution influences distribution and substantivity. Finally, data on the difference between advancing and receding wettability indicate how this hysteresis is related to the nature of the surface and to surface coverage by treating agents.
Thermokinetics and chemorheology of the cure reactions of the tetraglycidyl diamino diphenyl methane–diamino diphenyl sulfone epoxy systems
Authors: Apicella A. , Nicolais L. , Iannone M. , Passerini P.
Published: April 2003

The cure behavior of commercial grade TGDDM–DDS mixtures of compositions ranging from 10 to 100 phr of hardener and the thermal polymerization of the epoxy component are analyzed by means of differential scanning calorimetry. The kinetic parameters and heats of reaction determined in isothermal and dynamic scans suggest that DDS primary amine addition and epoxide etherification dominate the cure reactions. The primary amine epoxide addition is characterized by overall heat of reaction (referred to the weight of the epoxy component) of 255 cal/g and by an activation energy of 16.6 kcal/mol. The corresponding values for the etherification reaction are, respectively, 170 cal/g and 41 kcal/mol. A method of derivation of the epoxide conversion from the heat evolved in DSC thermal scans of these systems is presented. The results are in good agreement with independent IR determinations. The steady shear and oscillatory viscosity measurements and the calorimetric analysis of the isothermal cure at 140°C, 160°C, and 180°C of a TGDDM–DDS mixture containing 35 phr of hardener indicate that gelation is principally governed by the primary amine addition. The gelation limits calculated in isothermal tests by combining the calorimetric analysis and the theory describing the nonlinear copolymerization of the tetrafunctional TGDDM with an essentially difunctional DDS were in good agreement with the values experimentally determined through rheological measurements.
High density polyethylene/polystyrene blends: Phase distribution morphology, rheological measurements, extrusion, and melt spinning behavior
Authors: Min Kyonsuku , White James L. , Fellers John F.
Published: April 2003

An experimental study of the development of phase morphology, rheological properties, and processing behavior of mechanical blends of a polystyrene (PS) and a high density polyethylene (PE) is presented. Phase morphologies were determined by scanning electron microscopy for (i) products prepared in a screw extruder/static mixer system, (ii) samples removed from a cone‐plate viscometer, (iii) extrudates, and (iv) melt spun fibers. Disperse phase dimensions were measured. The values varied from 1–5 μm in the products from static mixers. The dimensions of the dispersed phase in the blend products from the cone plate and capillary die were of the same order. The melt‐spun fibers exhibited disperse phase dimensions as low as 0.35 μm. Polystyrene was extracted from the blend fibers producing small diameter, PE fibrils, or minifibers. Both the initial melts and the blends were rheologically characterized. The shear viscosity and principal normal stress difference N1 exhibit maxima and minima when plotted as a function of composition. The characteristics of extrudates and melt spinning behavior of the blends were investigated. The shrinkage of extrudates of PE is much greater than PS. Additional small amounts of PE to PS greatly increase its shrinkage. Addition of PE to PS initially increases extrudate swell, though the swell shows maxima and minima when considered as a function of composition. The positions of the maxima and minima correspond to those of N1. The onset of draw resonance has been investigated in isothermal melt spinning. Wide angle X‐ray diffraction studies have been carried out on blend fibers and the orientation of the crystalline polyethylene regions has been determined as a function of process conditions. This orientation decreases rapidly with the addition of polystyrene when the melt‐spun filaments are compared at the same spinline stress or drawdown ratio.
The fabrication and characterization of polymer optical conductors
Authors: Srinivasan B. , Martin G. C.
Published: April 2003

Polymer microstructures were evaluated as thin film optical conductors. The polymer waveguides were fabricated from a photosensitive silicone polymer by selectively crosslinking the polymer with the near‐ultraviolet radiation from an argon ion laser. The optical transmittance properties of curved and linear microstructures were characterized using an optical sensing technique. For the curved guides, an exponential decay in the intensity of transmitted light with guide length was observed. The linear guides exhibited an oscillatory relationship between output intensity and length over a range of 2 mm in length. The nature of the results for the linear guides was explained by considering the variations in the refractive index across the polymer microstructure and by comparison with the optical behavior of graded‐index glass fibers.
Additives in transparent glassy polymers: Concentration profiles obtained by solvent diffusion technique
Authors: Guerra G. , Moschetti A. , Carfagna C. , Mandara U. , Cutolo A. , Solimeno S.
Published: April 2003

Concentration profiles of additives, introduced in transparent glassy polymers by solvent diffusion technique, are analyzed by measuring refractive index profiles. Such profiles depend not only on the diffusion conditions (temperature, time, kind of solvent, concentration), but also on the conditions of solvent desorption from the polymer (temperature, pressure, solvent, and additive volatilities). In particular, poly(methyl methacrylate) (PMMA) samples modified in an outer shell by zinc chloride carried by methanol are considered.
Solution NMR study of the post‐polymerization crosslinking agent N,N′‐(2‐propyloximino)‐4,4′‐methylenebis(phenylcarbamate). I
Authors: Bassett Walter H. , Sun Tong , Porter Roger S.
Published: April 2003

Because of its possible use as a blocked “post‐polymerization crosslinking agent” for polymers containing labile hydrogen, the structure of the acetone oxime adduct of 4,4′‐methylenebis‐(phenylisocyanate) has been determined. 13C and 1H nuclear magnetic resonance (NMR) spectroscopy has identified this product to be N,N′‐(2‐propyloximino)‐4,4′‐methylenebis(phenylcarbamate). Chemical shift assignments were based on information obtained by proton decoupled, off‐resonance decoupled, and gated decoupled 13C‐NMR, proton‐NMR, and semiemperical substituent chemical shift (SCS) parameters.
An NMR study of the dissociation of N,N′‐(2‐propyloximino)‐4,4′‐methylenebis(phenylcarbamate) and its crosslinking of polymers containing labile hydrogens. II
Authors: Sun Tong , Bassett Walter H. , Porter Roger S.
Published: April 2003

Nuclear magnetic resonance spectroscopy has been used to study the dissociation and reaction of N,N′‐(2‐propyloximino)‐4,4′‐methylenebis(phenylcarbamate), as a crosslinking agent for polymers containing labile hydrogens. The crosslinking of poly(acrylic acid), polyacrylamide, and poly(vinyl alcohol) was found to result upon heating each to 150°C for 10 min with this component at 2–10 wt %.
Structure–property relationships of anionic exchange membranes for Fe/Cr redox storage batteries
Authors: Arnold Charles , Assink Roger A.
Published: April 2003

Membranes with lower area resistivity, higher selectivity, and reduced susceptibility toward fouling were required to improve the efficiency and lifetime of Fe/Cr redox storage batteries. The relationship of membrane structure to these electrochemical properties was not well understood. To gain a better understanding of structure–property relationships, a series of model membranes was synthesized in which the degree of crosslinking, ion exchange capacity, and porosity could be varied independently. This permitted the completion of several factorial studies in which the effect of each structural variable and interaction between variables could be defined and quantified. It was found that increasing the ion exchange capacity had a beneficial effect on all three electrochemical properties. Increasing the porosity reduced the resistivity and fouling but resulted in poorer selectivity. The degree of crosslinking had no effect on resistivity but improved selectivity and reduced fouling was observed when this parameter was increased. These relationships are consistent with theoretical models that have been proposed to account for the behavior of ion exchange membranes in general. From this data, empirical models were constructed which could be used to predict the area resistivity and water content of other anionic exchange membranes.
Controlled degradation of polystyrene
Authors: Ide Syoaki , Ogawa Taichi , Kuroki Takeshi , Ikemura Tadashi
Published: April 2003

For the purpose of efficient utilization of waste polystyrene, the recovery method of a styrene oligomer having a molecular weight of 1000–3000 was studied. Thermal and catalytic degradations were carried out. It was impossible to obtain a styrene oligomer with a molecular weight less than 5000 by thermal degradation in the temperature range of 300–500°C. Catalytic degradation in the presence of silica–alumina catalyst in the temperature range of 190–230°C made it possible to control the decrease in molecular weight and to obtain a styrene oligomer having a molecular weight of 500–3000. Simultaneously, the molecular structures of the reaction products from thermal and catalytic degradations were determined by NMR analysis.
Procedure for evaluation of the Mark–Houwink constants
Authors: Dobkowski Zbigniew
Published: April 2003

An iterative procedure for evaluation of the Mark–Houwink constants, using the GPC universal calibration principle and the extended [η]–M relationship, is described. The procedure is recommended for newly prepared polymers of unknown average molecular weights. An example is given for bisphenol C‐2 polycarbonate.
Immobilization of cellulase using porous polymer matrix
Authors: Kumakura Minoru , Kaetsu Isao
Published: April 2003

A new method is discussed for the immobilization of cellulase using porous polymer matrices, which were obtained by radiation polymerization of hydrophilic monomers. In this method, the immobilized enzyme matrix was prepared by enzyme absorbtion in the porous polymer matrix and drying treatment. The enzyme activity of the immobilized enzyme matrix varied with monomer concentration, cooling rate of the monomer solution, and hydrophilicity of the polymer matrix, taking the change of the nature of the porous structure in the polymer matrix. The leakage of the enzymes from the polymer matrix was not observed in the repeated batch enzyme reactions.
Polymerization of tung oil by reaction of phenols with tung oil
Authors: Yoshimura Yukio
Published: April 2003

Investigation was made on the mechanism of polymerization in reactions of tung oil and phenols in the presence of an acid catalyst. It was made by means of comparative HLC and NMR analyses of the products of tung oil self‐polymerization, other varied vegetable oil‐various phenol reactions, and tung oil‐various‐in‐functionality phenol reactions under given conditions. As a result, it was confirmed that polymerization in reactions of tung oil and phenols is attributed not to tung oil self‐polymerization but to di‐ or trialkylation, with tung oil, of phenols, which can serve as crosslinking agents of tung oil.
Luminescence emission of isotactic polypropylene
Authors: Osawa Zenjiro , Kuroda Hideyuki , Kobayashi Yutaka
Published: April 2003

In order to elucidate the origin of luminescent species in unstabilized commercial isotactic polypropylene (IPP), effects of hexane extraction and exposure of the extracted IPP film to the atmosphere on both fluorescence and phosphorescence emissions were examined. Fluorescence emission from the unextracted IPP film disappeared by the extraction, and only a very weak phosphorescence emission was found. During the exposure of the extracted IPP film to the atmosphere, both fluorescence and phosphorescence emissions appeared again. The intensity of the spectra increased with the exposure time and finally almost reached that from the unextracted IPP film. The results indicated that main fluorescent species in IPP are foreign impurities originating from an ambient atmosphere, and that contribution of a very minor amount of phosphorescence species such as carbonyl groups incorporated with the polymer was scarce.
Semi‐ and fully interpenetrating polymer networks based on polyurethane–polyacrylate systems. V. An isomerically related semi‐1‐interpenetrating polymer network system
Authors: Hourston D. J. , Zia Y.
Published: April 2003

A series of polyurethane–poly(vinyl acetate) semi‐1‐IPNs were synthesized, and certain physical properties investigated. Electron microscopy showed all the materials to be substantially phase‐separated, but evidence from dynamic mechanical analysis indicated that some mixing occurred, because the polyurethane glass transition was shifted in both the tan σ− and the E″–temperature curves. The variation of modulus with composition was found to be reasonably close to the predictions of the Davies equation. When the exponent in that relation was changed to ⅙, a good fit was obtained. Synergism with respect to tensile strength was observed for two of the semi‐1‐IPNs. Stress–relaxation measurements, over a fairly narrow temperature range, were made on the semi‐1‐IPN containing 40% by weight of the polyurethane network. A master curve was constructed. It was noted that the WLF equation was not obeyed by this semi‐1‐IPN at temperatures above about 50°C.
Plasma polymerized membranes and gas permeability. I
Authors: Yamamoto Minoru , Sakata Jiro , Hirai Masana
Published: April 2003

Gas permeability of composite membrane prepared by plasma polymerization of various organic compounds was studied. In the membrane, a pinhole‐free polymeric thin film was formed on a porous substrate. This film below 0.2 μm in thickness had sufficient mechanical strength for gas separation. The composite membranes were recognized to have high permeability and high permselectivity. Especially, the membranes prepared from hexamethyldisiloxane showed high permeation rate for oxygen, and those prepared from 1‐hexene or cyclohexane showed high permselectivity between oxygen and nitrogen. chemical structure of plasma‐polymerized film prepared from hexamethyldisiloxane was similar to that of dimethylpolysiloxane with a crosslinking of the polymer. The high permeability and high permselectivity of this film is considered to be due to its structure as mentioned above.
The elastic moduli of particulate‐filled polymers
Authors: Theocaris P. S. , Sideridis E.
Published: April 2003

The static and dynamic elastic moduli of particulate composites, consisting of two phases, one of which has isotropic–elastic and the other linear viscoelastic properties, were studied. For this purpose a model defining the approximate equations for determining the elastic modulus of a composite from the properties of the constituent materials was used. Classical theory of elasticity was applied to this simplified model of a composite‐unit cell. The following assumptions are made: (i) filler particles are spherical; (ii) fillers are completely dispersed; and (iii) the volume fraction of fillers is sufficiently small, so that any interaction among fillers may be neglected. A class of iron‐filled epoxy composites was subjected to tests in order to compare the theoretical values with the experimental results. The elastic modulus calculated by the expression derived in this study seems to corroborate with the experimental results fairly well. Finally, by applying the correspondence principle to this expression, theoretical relationships for the dynamic storage and loss moduli were also derived.
Dimensional changes during solvent‐induced crystallization of poly(ethylene terephthalate) films
Authors: Durning Christopher J. , Rebenfeld Ludwig
Published: April 2003

The sample dimensional changes accompanying diffusion with induced crystallization in amorphous poly(ethylene terephthalate) (PET) films are analyzed. Initially, the film's lateral area remains practically constant, but near the end of the process, it increases rapidly, consistent with non‐Fickian models for diffusion. The ultimate relative thickness increase is about double that for the lateral dimension, implying that plastic deformation in the thickness direction accompanies the sorption. Plots of fractional area increase (ΔA/ΔA∞) vs. fractional weight gain (W/W∞) indicate severe softening of the polymer by the penetrant.
Improvement of hydrophilicity of polypropylene by liquid‐phase mutual irradiation of acrylics
Authors: Pugh Colleen , Hsieh You‐Lo
Published: April 2003

N‐butanol was found to promote the inclusion of methyl acrylate and methyl methacrylate in polypropylene, but did not affect the uptake of acrylic acid in the polymer. Polymerization of the monomers was, however, not significantly affected by the use of this swelling agent. The monomer exchange process followed by a liquid phase mutual irradiation has proved to be very effective in enhancing the polymerization of all three monomers on polypropylene. Optimum radiation doses for effective polymerization of the monomers were found to be around 3.2 Mrad for methyl acrylate and around 4.8 Mrad for methyl methacrylate and acrylic acid. Surface wettability of the film and moisture regain of the fiber were tremendously improved with all monomers regardless of the swelling agent and temperatures. Also, a low radiation dose of 1.6 Mrad was as effective as the higher doses. Methyl acrylate and methyl methacrylate modified fibers showed no marked changes in strength and elongation, but did result in a harsher hand. Acrylic acid modified fibers increased greatly in elongation, decreased to a greater extent in strength, and softened in hand.
Surface characterization of styrene/2‐hydroxyethyl methacrylate copolymer latex
Authors: Shirahama Hiroyuki , Suzawa Toshiro
Published: April 2003

Styrene/2‐hydroxyethyl methacrylate copolymer (PS/PHEMA) latex was prepared without soap. From an electron micrograph, this latex was found to be highly monodisperse. The surface characterization of PS/PHEMA latex was compared with that of polystyrene (PS) latex. Conductometric titration curves of these latexes revealed that both strong and weak acid groups existed on the latex surface. It was found that pH dependence of surface charges for these latexes was not very pronounced whereas negative values of ζ‐ potentials for PS/PHEMA latex were smaller than that for PS latex over the whole range of measured pH. This was interpreted on the basis of the difference in the structure of the electrical double layer for these latexes. Methylene Blue adsorption onto PS and PS/PHEMA latexes was measured as a function of pH, too. The pH dependence of the dye adsorption onto these latexes was hardly discernible. However, the amount of Methylene Blue adsorbed was somewhat greater onto PS latex than onto PS/PHEMA latex. This result might be attributed to the strength of hydrophobic interaction between dye and latex. It was suggested that PS/PHEMA latex was more hydrophilic than PS latex in spite of having about the same surface charge as PS latex.
Epoxy resin cure. I. Fluorine‐19 NMR of boron trifluoride monoethylamine and fluoroboric acid
Authors: Smith Robert E. , Larsen Fred N. , Long Charles L.
Published: April 2003

Fluorine‐19 NMR is used to examine the role of boron trifluoride monoethylamine (BF3–MEA) in epoxy resin cure. Spectra were first recorded in a variety of solvents suitable for dissolving different epoxy resins. All spectra contained a peak due to fluoroboric acid. Spectra of BF3–MEA in orthodichlorobenzene were then recorded at elevated temperatures. The floroboric acid peak area increased, indicating that the BF3–MEA was being hydrolyzed. Results indicate that, at temperatures above 100°C, BF3–MEA is completely hydrolyzed within 5 min to fluoroboric acid.
Saturated and unsaturated polyesters based on 1,3‐(dicarboxymethoxy)benzene
Authors: Shaaban A. F. , Hamed A. A. , El‐Karim I. A. G.
Published: April 2003

Saturated polyesters were prepared by the reaction of 1,3‐(dicarboxymethoxy)benzene with ethylene, diethylene, tetramethylene, and hexamethylene glycols. Also, unsaturated polyesters were prepared by the reaction of 1,3‐(dicarboxymethoxy)benzene and maleic anhydride with the same glycols. All the polyester resins obtained have been characterized, and the unsatureated polyesters were found to cure with styrene. The properties of the cured polyesters in the form of films were determined. IR and 1H‐NMR spectroscopy were used for both qualitative and quantitative analyses of the polyesters as well as their hydrolyzate products, after curing with styrene.
Use of polymer‐bound metals as fire retardants in polyethylene–silicon blends
Authors: Schroll A. L. , MacLaury M. R.
Published: April 2003

Lead compounds and silicone gum when blended into polyethylene act as synergistic fire retardant. The incorporation of lead into the polymer network via lead carboxylate formation through polyethylene grafted with maleic anhydride has been studied as a means of improving the metal dispersion and flammability behavior. Lead was also incorporated directly into a polymer backbone via the formation of lead polyesters. The use of other metal compounds as fire retardant additives has also been studied. No special behavior was seen for polymer‐bound lead relative to non‐polymer bound lead, and other metals were not found to be effective replacements for lead in polyethylene graft maleic anhydride.
Resistivity behavior of carbon‐black‐filled silicone rubber in cyclic loading experiments
Authors: Kost J. , Narkis M. , Foux A.
Published: April 2003

Stress–relaxation and cyclic loading behavior of silicone/EC black vulcanizates have been measured at several strains up to 0.8. The first extension is always very different from the subsequent ones. Orientation effects of anisometric carbon particles are starting to play an important role only after a certain elongation has been exceeded. The conductive elastomers can be stabilized by mechanical preconditioning procedures involving cycling at high extensions. The stabilized specimens then behaved nearly reversibly when cycled at strains below about 50% of the previous preconditioning strain. The resistivity‐extension cycle consists of a single peak or a double peak per a strain peak depending on the strain level. The transition from single to double resistivity peaks depends on whether particle orientation takes place during the stretching process, which depends upon the level of strain.
Membrane structure and permeation properties of poly(vinyl chloride)/liquid crystal composite membrane
Authors: Kajiyama Tisato , Washizu Shintaro , Takayanagi Motowo
Published: April 2003

A series of polymer/liquid crystal composite membranes, at several weight ratios, was prepared casting from a tetrahydrofuran solution of poly(vinyl chloride) (PVC) with N‐(4‐ethoxy‐benzylidene)‐4′‐butylaniline (EBBA). From the thermal analysis, microscopic observation, mechanical property, and gas permeation studies, the properties for a series of PVC/EBBA composite membranes were derived. DSC showed that PVC and EBBA were quite miscible and EBBA in composite membranes at below 30 wt % was molecularly dispersed without forming crystal domains. Morphological observations exhibited that EBBA molecules interpenetrated in a continuous phase among the 3‐dimensional spongy networks of PVC matrix in the case of the 40/60 (PVC/EBBA, in wt %) composite membrane. Stable retention of EBBA in the composite membrane and its high mechanical durability might arise from such an aggregation structure. The permeability coefficients to oxygen gas, P02 and nitrogen one, PN2 through the 40/60 (PVC/EBBA) composite membrane showed a discontinuous jump with a several–tenfold increase in the vicinity of the crystal–nematic transition temperature TKN of EBBA. The magnitudes of P02 and the separation factors P02/PN2 above TKN were of the order of 10−9 cm3 (STP) cm−1 s−1 cm Hg−1 and 2–3, respectively. The value of P02/PN2 reached a maximum just above TKN. The P02 − P02/PN2 relationship above TKN exhibited an unusual behavior as P02/PN2 increased with an increase in P02.
Synthesis and transport properties of thin film composite membranes. II. Preparation of sulfonated poly(phenylene oxide) thin film composite membranes for the purification of alberta tar sands waste waters
Authors: Huang R. Y. M. , Kim J. J.
Published: April 2003

Thin film composite membranes of sulfonated poly(phenylene oxide) (SPPO)–polysulfone (PS) (SPPO–PS) were prepared by coating the hydrogen or sodium form of SPPO onto various porous substrates such as polysulfone (PS). The effects of membrane preparation conditions and feed water variables on the salt rejection and production rates were investigated using reverse osmosis. Purification of the waste waters from the Alberta heavy oil fields for desalination and recycling use was carried out. Production rates and salt rejections for the various feeds were found to be in the range of 5–20 gfd (gallons/ft2 day) and 80–99% respectively at 600 psig and 20°C, depending on the experimental conditions and membrane properties.
Depolymerization of fluoroalkyl methacrylate polymers as studied with thermogravimetry
Authors: Hayakawa Kiyoshi , Kawase Kaoru , Yamakita Hiromi
Published: April 2003

Thermal behaviors of a few kinds of poly(fluoroalkyl methacrylate) prepared by γ‐or UV‐ray polymerization were investigated by using thermogravimetric measurements with the intermittent analysis of the gaseous products. The degradation of fluoroalkyl methacrylate polymers, monomeric units of which were CH2=C(CH3)COOCH2(CF2CF2)nH, n = 1, 2, and 3, proceeded according to the depolymerization mechanism reproducing the pristine monomer exclusively, but the thermogram in inert atmosphere showed the features of a two‐step reaction. Two species of polymer differing in the heat stability were supposed to exist in the polymeric substance produced by γ‐ or UV‐ray irradiation, and the fraction of polymer having lower heat stability increased with the increasing length of the fluoroalkyl ester group. In air, however, the thermogram of poly(fluoroalkyl methacrylate) showed no such a stepwise weight decrease as was observed in inert atomsphere with the elevating temperature, and the temperatures at which the depolymerization was introduced shifted to a much higher region. The results were ascribed to the reaction of initiating polymer radicals produced on polymer having lower stability with oxygen to form hydroperoxide, which once stabilized the polymer radicals and obstructed the initiaition of the unzipping reaction till higher temperature.
Dynamic mechanical properties of highly loaded ferrite‐filled thermoplastic elastomer
Authors: Saini D. R. , Shenoy A. V. , Nadkarni V. M.
Published: April 2003

The dynamic mechanical properties in terms of the storage modulus E′, loss modulus E″, and the loss tangent δ has been studied for highly filled magnetic polymer composites. The effect of surface treatment on the relaxation spectra has been clearly elucidated and quantitative values indicating the extent of polymer–filler interactions have been given. Various models have been tested for describing the viscoelastic behavior of such highly filled systems. The Wiechert model using a single‐arm with a Cole–Cole parameter has been shown to effectively fit the Argand diagram in the case of the present highly filled systems.