bluuebunny/crossref_metadata_2025 huggingface dataset:
Utilization of wastes of foam polystyrene as sorbents
Authors: Simitzis J. , Fountas D.
Published: April 2003

Wastes of foam polystyrene were dissolved in styrene and copolymerized with DVB and the final product was sulfonated with H2SO4 (group B). Group A of cross‐linked polystyrene was synthesized using styrene and divinylbenzene (DVB) in the presence of n‐heptane (macroporous ion exchangers) and then was sulfonated with H2SO4. The chemical structure of the cross‐linked polymers before and after sulfonation was determined by infrared spectroscopy. The ion‐exchange capacity was higher for the polymers of group A. The poresize distribution for polymers of group A was determined and the average pore diameter (4V/A) of 39.9 nm for a representative polymer resulted. The degree of swelling of the polymers and their adsorption for methylene blue and alizarin yellow were also determined. The degree of swelling in toluene is decreased by increasing the ratio of DVB in the initial mixture and by sulfonation. The adsorption of methylene blue and alizarin yellow is strongly increased by the sulfonated polymers in comparison with the unsulfonated. As far as group B is concerned, the adsorption of alizarin yellow on the sulfonated polymers, which have higher cross‐linking and lower sulfonation, increased more, especially at the initial time. The networks of both groups examined are different. The polystyrene wastes were incorporated into the whole network to an extent of 15–35%. Such investigations could contribute to the utilization of wastes of polystyrene in the direction of sorbents and especially if the polystrene wastes are contaminated with other polymers. © 1995 John Wiley & Sons, Inc.
Semiinterpenetrating polymer network latexes via concentrated emulsion polymerization
Authors: Ruckenstein Eli , Li Hangquan
Published: April 2003

Latexes of semiinterpenetrating polymer networks (SIPN) of polyurethane (PU) and poly(methyl methacrylate) (PMMA) were prepared via the concentrated emulsion polymerization. In this procedure, a partially cross‐linked PU was first prepared in a low polarity solvent from the appropriate precursors. Subsequently, MMA and an initiator were introduced into the solution, and the solution was used as the dispersed phase of a concentrated emulsion in water. Finally, SIPN latexes were obtained via the polymerization of the concentrated emulsion. For comparison purposes, SIPN materials have been also prepared via bulk polymerization. The studies with differential scanning calorimetry and transmission electronic microscopy showed that partial interpenetration was achieved in the SIPN latexes. The tensile behavior and particle morphology of the SIPN materials were investigated by changing the proportion of PU, the molar ratio of NCO/OH, the theoretical cross‐link density, and the concentration of the initiator. The SIPN latexes prepared possess a high toughness. © 1995 John Wiley & Sons, Inc.
Coating water‐swellable polymer latexes by interfacial polymerization
Authors: Ruckenstein Eli , Hong Liang
Published: April 2003

Two techniques of coating water‐swellable polymer latexes (hydrogels) with an inorganic or organic layer were developed, based on interfacial polymerization. The hydrogel latexes were prepared by inverse suspension polymerization. The first kind of interfacial polymerization is hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS) or 3‐(trimethoxysilyl) propylmethacrylate (TMS‐PMA) on the surface of hydrogel latexes. The hydrochloric acid, which is the catalyst for this reaction, was previously loaded into the hydrogel latexes. The HCL‐containing hydrogel latexes were then suspended in an organic solution of TEOS or TMS‐PMA. The hydrolysis and condensation occur only at the surface of each hydrogel particle and the generated SiO2 or SiO(PMA) network covers the hydrogel latexes. The second interfacial polymerization is polymerization of methylenedi‐p‐phenyl diisocyanate (MDI) and triethylene glycol (TEG) on the surface of hydrogel latexes. TEG was deposited on the hydrogel by suspending the hydrogel powder in a tetrahydrofuran (THF) solution of TEG and evaporating the THF. The TEG‐deposited hydrogel powder was then suspended in an organic solution containing both MDI and the catalyst dibutyltin dilaurate (DBTL). The MDI and DBTL molecules react with the TEG molecules only at the surface of the hydrogel particles, and the polyurethane P(MDI‐TEG) thus formed wraps the particles. Based on these two coating procedures, three kinds of materials were obtained: SiO2 coated hydrogels, SiO‐(PMA) coated hydrogels and P(MDI‐TEG) coated hydrogels. Soft polyether brushes were grafted to the SiO‐(PAM) coated latexes. The P(MDI‐TEG) coated hydrogels were used as reservoirs for β‐hydroethyltheophylline (β‐HETP), and the release of the latter molecules from the coated hydrogels was investigated. © 1995 John Wiley & Sons, Inc.
Vulcanization of 1‐chlorobutadiene–butadiene rubber with diepoxy compound
Authors: Sando Katsumi , Hashim Azanam Shah , Ikeda Yuko , Kohjiya Shinzo , Yamashita Shinzo , Kawabata Nariyoshi
Published: April 2003

Diepoxy vulcanization system of 1‐chlorobutadiene–butadiene rubber(CB–BR) having hydroxyl groups with diglycidyl ether of bisphenol A (DGEBA) was studied in the presence of acid anhydrides. Phthalic anhydride (PAn), hexahydrophthalic anhydride (HAn), maleic anhydride (MAn), and succinic anhydride (SAn) were investigated as occuring agents. The results of this investigation indicated that the hydroxyl groups attached to the polybutadiene backbone react with DGEBA to afford a CB–BR vulcanizate rate depended on the kinds of acid anhydrides in the following order: PAn > MAn > SAn > HAn. It is assumed that the reaction between the hydroxyl group in CB–BR and acid anhydride was the rate‐determining step. The vulcanization of CB–BR with a higher amount of DGEBA afforded resinous rubber vulcanizates. Thus, DGEBA was concluded to act not only as a curing agent, but also as a reinforcing agent for CB–BR. © 1995 John Wiley & Sons, Inc.
Studies on mesomorphic behaviors of segmented azoxy polyester containing polyoxyethylene
Authors: Huang Jaine Ming , Kuo Jen Feng , Chen Chuh Yung
Published: April 2003

A series of a segmented copolymer, poly(4,4′‐dioxy‐2,2′‐dimethyl‐azoxybenzene dodecanedioyl)‐co‐polyoxyethylene 400 (PMABD‐co‐POE) was prepared; the average chain lengths n, of the PMABD studied are 8.1 to 20.6. The thermotropic properties and the mesophase texture of the segmented copolymers were elucidated as functions of n using a differential scanning calorimeter and a polarized optical microscope with a hot stage. The results show that the incorporation of POE with PMABD decreases the intermolecular interaction force and changes the chain flexibility. The nematic droplets obtained near the isotropic temperature all exhibited a twisted bipolar configuration. Also, in the undercooling process, the nematic textures obtained before crystallizing varied with n. The copolymers containing n ≥ 17, like PMABD, develop a Schlieren texture, whereas those containing n < 17 develop a distorted‐stripe conformation. A possible mechanism for interpretation of the obtained results has been proposed. © 1995 John Wiley & Sons, Inc.
Study of crosslinking density in polydimethylsiloxane networks by DSC
Authors: Vera‐Graziano R. , Hernandez‐Sanchez F. , Cauich‐Rodriguez J. V.
Published: April 2003

A calorimetric study for estimating crosslinking densities of polydimethylsiloxane (PDMS) networks is presented. It involves the experimental determination of the heat capacities of the polymer with (C) and without (C) crosslinking. The theoretical basis of the method is described as well as the procedure used for the determination of the Cps. The crosslinking densities of PDMS networks, determined by absorbency (swelling) measurments, using the Flory‐Rehner equation, and by the method described here, are compared. The PDMS, obtained by the anionic synthesis of octamethylcyclotetrasiloxane, was analyzed by gel permeation chromatography and infrared spectroscopy. Separate samples of the polymer were further crosslinked at different network densities. The Cps and the thermal stabilities were determined by DSC and TGA, respectively. The results indicate that the crosslinking density ratios of the polymer networks calculated by the relation ΔC/C are in reasonable agreement with those obtained from absorbency measurements. The crosslinking density can also be obtained from heat capacity measurments if the density of the network is known at the temperature that ΔCp is obtained. © 1995 John Wiley & Sons, Inc.
General formula for bending beam determination of case II diffusion in polymer‐containing bilayer structures
Authors: Jou Jwo‐Huei , Yang An‐Kuo , Chang Ying‐Lun , Jou Jwo‐Min
Published: April 2003

An exact formula has been presented to correlate the bending curvature cariation ratio, Ω, of any given bilayer structure comprising a solvent‐swellable polymer layer with diffusion time, t, under case II diffusion. The formula can be used to determine the diffusion front velocity, v, for layered structures comprising a thick polymer film on a thin substrate or vice versa when subjected to solvent diffusion. According to this formula, there is little effect from plasticization or swelling in the transverse direction on the diffusion curve of Ω vs. t if the polymer layer to be investigated is relatively thin and its intrinsic hygroscopic strain ratio is less than unity. By using this model, the diffusion of N‐methyl pyrollidinone (NMP) in a 18‐μm rodlike pyromellitic dianhydride p‐phenylene‐diamine (PMDA‐PDA) polymide film, coated on a 75‐μm silicon substrate, is found to be case II with a diffusion front velocity of 1.84 × 10‐7 cm/s. © 1995 John Wiley & Sons, Inc.
Structure and properties of tin‐containing polymers deposited from tetramethyltin HF plasma
Authors: Ying T. H. , Sarmadi A. M. , Hop C. E. C. A. , Denes F.
Published: April 2003

There has been an increasing interest in depositing metal or metal‐containing thin films through plasma polymerization for various applications. This work deals with the plasma graft polymerization of tetramethyltin (TMT) on polypropylene surfaces with an aim of producing special electrical and optical coatings. The fragmentation of TMT under cold plasma conditions and the recombination of discharge‐generated active species were studied by analyzing the resulting molecular mixture trapped outside of the plasma zone by HR‐MS and GC‐MS techniques. It was found that the predominant ionic fragment is m/z = 165, and the most probable intermediate structure of the polymer formation mechanism is hexamethylditin. The structure of polymeric layers deposited on various substrates were investigated by ESCA and FT‐IR methods. Intense oxidation of tin‐based polymeric layers were observed under open laboratory conditions. The existence of weak SnSn and SnC bonds in the polymeric structure is suggested to be responsible for this reaction. This phenomenon was associated with enhanced UV transparency. Based on analytical data a plasma‐enhanced polymerization mechanism of TMT is proposed. © 1995 John Wiley & Sons, Inc.
Application of poly(vinyl alcohol) with an alkyl end group containing anionic groups to coal–water slurry as a dispersant
Authors: Yamauchi Junnosuke , Terada Kazutoshi , Sato Toshiaki , Okaya Takuji
Published: April 2003

Anionic groups were introduced with copolymerization of corresponding vinyl monomers with vinyl acetate into poly(vinyl alcohol) (PVA) with an alkylthio end group. The polymers were investigated as a dispersant for coal‐water slurry (CWM). Anionic groups such as sodium sulfonate and sodium carboxylate enhance remarkably the ability of PVA with an alkylthio end group to disperse coal. Sodium polyacrylic acid with an alkyl end group also showed a good ability of dispersing coal. The order of the ability of dispersing coal in these polymeric dispersants along with sodium napthalene sulfonate formaldehyde condensate (NSF) varied by the kind of coal used. In cases of the polymeric dispersants, the fluidity of coal in terms of dependence of viscosity on shear rate also varied, from dilatency to thixotropy, in accordance with coal used. Impurities in coal as well as surface properties of coal particles might play important roles in the properties of CWM. © 1995 John Wiley & Sons, Inc.
The properties of soldering mask hardened by means of UV using acrylate and methacrylate oligomers
Authors: Matynia Tadeusz , Kutyłkea Romualda , Bukat Krystyna , Pieńkowska Barbara
Published: April 2003

The properties of soldering masks based on epoxyacrylic, epoxymethacrylic esters, and monomers: 2‐ethylhexyl acrylate, triethylene glycol dimethacrylate, and triethylene glycol phthalate dimethacrylate have been described. The thixotropic properties, printability, adhesion to the surface, and resistance to soldering have been determined. © 1995 John Wiley & Sons, Inc.
Preferable structure of poly(ethylene glycol) for grafting onto a cellulosic membrane to increase hemocompatibility without reduction in solute permeability of the membrane
Authors: Kanamori Toshiyuki , Sakai Kiyotaka , Fukuda Makoto , Yamashita Yasuhiko
Published: April 2003

Swelling layers formed by poly(ethylene glycol) (PEG) chains grafted onto surfaces of a cellulosic membrane are known to improve hemocompatibility of the membrane. Three types of hemodialysis membranes were derived from the same regenerated‐cellulose hollow‐fiber membrane by grafting PEG with different formulas onto the surfaces to clarify the influence of the grafted PEG chains on solute permeability of the membranes. Determination of volume fractions of nonfreezing water contained in the membranes by differential scanning calorimetry revealed that most of the PEG chains were grafted onto the external surfaces and less into the pores in the membranes. Permeability of vitamin B12 for the PEG‐grafted membranes except for the one with the shortest PEG chains was reduced as compared with the original membrane, while that of tritium‐labeled water for all the PEG‐grafted membranes was the same as that of the original membrane. Structural parameters only of the PEG‐grafted membrane with the largest alkyl groups at the terminal of the PEG chains were different from those of the other PEG‐grafted and original membranes. The shorter PEG chains with the larger terminal alkyl groups are suitable for grafting onto a cellulosic membrane to increase hemocompatibility of the membrane without significant reduction in the solute permeability of the membrane. © 1995 John Wiley & Sons, Inc.
Polymerization of phosphor‐containing oligomer induced by electron‐beam irradiation
Authors: Yoshizawa Iwao , Kohara Choji , Kaji Kanako , Hatada Motoyoshi
Published: April 2003

Studies have been carried out on the polymerization of vinyl phosphonate oligomer in a form of thin liquid layer induced by electron‐beam irradiation under various reaction conditions. It was found that the dose‐rate exponent on the rate of polymerization was 0.92, that the presence of remaining diluent below 10% did not disturb the polymerization, but that the presence of oxygen retarded the reaction when the film thickness was as thin as 20μm. Intermittent irradiation was effective to increase the conversion to the polymer. © 1995 John Wiley & Sons, Inc.
Assessment of degree of fusion of rigid PVC from inverse gas chromatographic measurements
Authors: Qin Renyan , Schreiber H. P. , Rudin Alfred
Published: April 2003

Inverse gas chromatography of alkanes has been used to assess the degree of fusion of rigid polyvinyl chloride (PVC) extrudates. The relative degree of fusion is provided by ratios of the retention volumes of the alkane probe molecules in the bulk of the PVC. This method is nonintrusive and can be used to measure degree of fusion quantitatively if a completely fused reference material can be provided. The present analysis involves evaluations of the contributions to the overall retention volume of the alkane probes, resulting from adsorption and from bulk diffusion. The diffusivity of the alkanes was clearly dependent on the processing history of the PVC extrudate. A direct variation was observed between the size of the diffusing molecules and their residence time as adsorbates on the polymer surface. © 1995 John Wiley & Sons, Inc.
Introduction of amidoxime groups into cellulose and its ability to adsorb metal ions
Authors: Kubota Hitoshi , Shigehisa Yasumichi
Published: April 2003

Introduction of amidoxime groups into cellulose substrate was investigated by reaction of cyano‐group‐containing celluloses such as cyanoethylcellulose (CE‐Cell) and acrylonitrilegrafted cellulose (G‐Cell) with hydroxylamine at 70°C in water medium (pH = 7.0). Dissolving pulp from softwood was used as the cellulose sample, and photografting was applied to the preparation of G‐Cell, where hydrogen peroxide was used as a photoinitiator. Degree of substitution (DS) of CE‐Cell and percent grafting of G‐Cell employed were less than 1.5 and 40, respectively. The amidoximation of CE‐Cell proceeded easily, and the amidoxime content increased with increasing the reaction time and increasing the concentration of hydroxylamine, but the amidoxime content of G‐Cell decreased significantly at longer reaction time. The amidoximated samples prepared by CE‐Cell exhibited an ability to adsorb metal ions such as Cu2+, Ni2+, and Co2+, and the adsorbed amount of Cu2+ was highest among the three metal ions. Moreover, the adsorption of Cu2+ varied depending on the DS of CE‐Cell. That is, the absorption ability was reduced when the sample was prepared using CE‐Cell with higher DS. The amidoximated samples prepared from G‐Cell showed adsorption of Cu2+ similar to samples prepared by CE‐Cell with lower DS, irrespective of percent grafting. © 1995 John Wiley & Sons, Inc.
Instrumented impact testing of castor‐oil‐based polyurethanes
Authors: Liu T. M. , Bui V. T.
Published: April 2003

Instrumented impact testing has been used to study castor‐oil‐based polyurethanes. The energy‐absorbed capacity of these materials in impact is dependent on several factors, such as the type of isocyanate, NCO/OH ratio, and testing temperature. An approximate but simple method for the low‐temperature impact testing was proposed. A change from ductile response to brittle fracture was observed as the temperature of the specimen was reduced. This characteristic ductile‐brittle transition temperature is to be found highly sensitive to crosslinking degree. © 1995 John Wiley & Sons, Inc.
Copolymers of methyl methacrylate and acrylate comonomers: Synthesis and characterization
Authors: Bhabhe M. D. , Galvankar P. S. , Desai V. M. , Athawale V. D.
Published: April 2003

Methyl methacrylate (MMA) has been copolymerized with n‐butyl acrylate (n‐BA), ethyl acrylate (EA), and 2‐ethylhexyl acrylate (2‐EHA) in solution at 70°C using benzoyl peroxide as free radical initiator. The copolymer composition was estimated by the 1H‐NMR spectroscopic technique. The copolymers were further characterized by IR, XRD, TGA, DTA, DSC, GPC, and solubility. The adhesive characteristics of the copolymers to cellulosic substrate are also reported. © 1995 John Wiley & Sons, Inc.
Monitoring of lamination processes in an autoclave with fiber‐optic infrared spectroscopy
Authors: Ge Zhengfang , Brown Chris W. , Brown Michelle
Published: April 2003

Curing reactions of certain laminates involve a series of chemical structure changes which occur with increasing temperature and/or pressure. This paper describes the use of a midinfrared chalcogenide fiber to monitor the lamination of polymer prepregs in an autoclave. The fiber optic was used both as a wave guide and as a sensing element for acquiring evanescent wave spectra. The spectra were measured by embedding the fiber optic in a polymer prepreg package. The polymer prepregs studied include epoxy, polyimide, and bismaleimide triazine (BT) resins. The degree of cure and an understanding of the kinetic processes were obtained from the absorbance changes in specific bands. This in situ sampling technique demonstrates a new area of Fourier transform infrared (FTIR) spectroscopy for following the formation of polymeric bonds. © 1995 John Wiley & Sons, Inc.
Preparation of high performance PET fiber by solution spinning technique
Authors: Wu Gang , Cuculo John A.
Published: April 2003

High molecular weight poly(ethylene terephthalate) (PET, IV = 3.30 dL/g) was extruded in attempts to prepare high performance fiber using the solution spinning method. Solution preparation, fiber coagulation, and mechanical properties of resultant fibers were examined. An as‐spun fiber exhibited high deformability when appropriate coagulation conditions were used. Tenacity and modulus of the resultant drawn fibers achieved 12.9 and 230 gpd, respectively, at draw ratio above 10. © 1995 John Wiley & Sons, Inc.
Fabrication and characterization of planar and channel polymer wave guides. I. Plasma‐polymerized HMDS films
Authors: Zeik D. B. , Dugan J. R. , Schroeder D. W. , Baur J. W. , Clarson S. J. , De Brabander G. N. , Boyd J. T.
Published: April 2003

Plasma‐polymerized hexamethyldisiloxane (HMDS) films have been prepared as both planar and channel wave guides. The optical attenuation results measured in both the planar and channel HMDS wave guides were found to be similar, thus demonstrating that the inherent solvent resistance and chemical inertness of the plasma polymerized films allows the use of common photoresist techniques, including application of the photoresist, photomasking, and subsequent etching. This may be contrasted with wave guides made from conventional polymers, where careful consideration must be given to photoresist/polymer compatibility, because the photoresist solvents may adversely affect the underlying polymer and lead to degradation of the material during processing. © 1995 John Wiley & Sons, Inc.
The charpy impact fracture behavior of phenolphthalein polyether ketone
Authors: Han Yanchun , Yang Yuming , Li Binyao , Wang Xuhui , Feng Zhiliu
Published: April 2003

The Charpy impact fracture behavior of notched specimens of phenolphthalein poly(ether ketone) (PEK‐C) has been studied over a range of temperature using a JJ‐20 Model instrumented impact tester. For PEK‐C, there exist two temperature regions which distinguish the fracture mechanism, and the brittle fracture was preferentially governed by slip or shear bands at relatively high temperatures, but by crazes at low temperatures. The temperature dependence of the ductility index (DI) shows similar peaks to the tan δ loss.
Fracture toughness of PC/PBT blend based on J‐integral methods
Authors: Lu Ming Luen , Chang Feng‐Chih
Published: April 2003

The fracture toughness of a polycarbonate/poly(butylene terephthalate) (PC/PBT) blend was determined using three different J‐integral methods, ASTM E813‐81, E813‐87, and hysteresis energy. The critical J values (J1c) obtained are largely independent of the cross‐head speed (range from 0.5 to 50 mm/min). ASTM E813‐81 and hysteresis energy methods result in comparable J1c values, while the E813‐87 method estimates J1c to be 60–80% higher. The critical displacement determined from the plots of hysteresis (energy and ratio) and the true crack growth length vs. displacement is very close. This indicates that the critical displacement determined by the hysteresis energy method is indeed the displacement at the onset of crack initiation and the corresponding J1c represents a physical event of crack initiation. © 1995 John Wiley & Sons, Inc.
Blends of poly(ethylene terephthalate) with co[poly(ethylene terephthalate‐p‐oxybenzoate)]. II. Composition effect on the rate of crystallization
Authors: Ou Cheng‐Fang , Lin Chen‐Chong
Published: April 2003

Poly(ethylene terephthalate) (PET) was blended with four different kinds of co[poly(ethylene terephthalate‐p‐oxybenzoate)] copolyesters, designated P28, P46, P64, and P82, with the level of copolyester varing from 1 to 15 wt %. All samples were prepared by melt‐mixing in a Brabender Plasticorder for 8 min. The crystallization behavior of samples were then studied via DSC. The results indicate that these four copolyesters accelerate the crystallization rate of PET in a manner similar to that of a nucleating agent. The acceleration of the PET crystallization rate was most pronounced in the PET/P28 blends with a maximum level at 10 wt % of P28, and in the PET/P28 blends, at 5 wt % of P82. The melting endotherm onset temperatures and the melting peak widths for the blends are comparable with those of neat PET. These results imply that the stability of PET crystalline phase in the blends does not change by blending. The observed changes in crystallization behavior, however, are explained by the effect of the physical state of the copolyester during PET crystallization as well as the content of the p‐oxybenzoate (POB) moiety in corporated into the blends. © 1995 John Wiley & Sons, Inc.
Moisture‐activated, electrically conducting bioadhesive hydrogels as interfaces for bioelectrodes: Effect of formulation factors on cutaneous adherence in wet environments
Authors: Woolfson A. D. , McCafferty D. F. , McCallion C. R. , McAdams E. T. , Anderson J. Mcc.
Published: April 2003

The effect of varying the composition of a polymer blend containing poly(methylvinyl ether‐maleic anhydride) copolymer on the Brookfield viscosity of the blend and on the in vitro bioadhesive forces of resultant cast films was assessed. An increase in copolymer concentration increased both blend viscosity and film bioadhesion. Increasing the plasticizer concentration did not significantly alter bioadhesion but did influence film flexibility. Blend pH affected both viscosity and bioadhesion. However, for films to be biocompatible, formulation within the skin pH range was desirable. Films exhibited the ability to ‘restick’ after initial adherence, allowing repositioning of the adhered film in vivo. Factorial design experiments (22) showed that an additive bioadhesive effect occurred when copolymer and PVP concentrations were increased in the polymer blend. However, no interaction between copolymer and plasticizer was observed. Addition of sodium chloride to the polymer blend, necessary to render films electrically conducting for use as bioelectrode interfaces, decreased blend viscosity but did not exert a significant effect on film bioadhesion. © 1995 John Wiley & Sons, Inc.
A molecular weight model in vinyl chloride–divinyl monomer suspension copolymerization before the gel point
Authors: Yingwu Luo , Zuren Pan , Zhixue Weng , Zhiming Huang
Published: April 2003

In this paper, a molecular weight model in the vinyl chloride (VC)–divinyl monomer suspension copolymerization was derived from the mechanism of VC two‐phase polymerization, with pseudokinetic constant method and the theory of the moments of chain length distribution. Furthermore, the behavior of average polymerization degree was simulated with the model at varied experimental parameters. The simulation phenomena were discussed in detail. It is concluded that our model can be useful to predict the behavior of DPw and to look inside the crosslinking mechanism in the VC–divinyl monomer copolymerization. © 1995 John Wiley & Sons, Inc.
Iron(III) chelating resins. VI. Stability constants of iron(III)–ligand complexes on insoluble polymeric matrices
Authors: Feng Minhua , Does Leen Van Der , Bantjes Adriaan
Published: April 2003

A method is presented for the determination of stability constants of iron(III)–ligand complexes on insoluble polymeric matrices based on a competition chelation reaction for iron(III) of the resin with a soluble chelator. Stability constants (K') were calculated for iron(III)–ligand complexes on DFO–Sepharose gel, HMP–Sepharose gel, AHMP–HEMA resin, and AHMP–DMAA resin. In these resins, desferrioxamine B (DFO, hexadentate ligand) or the 3‐hydroxy‐2methyl‐4(1H)‐pyridinone (HMP, bidentate ligand) was bound on insoluble polymeric matrices. The average values (log K') were: 26.6 (DFO–Sepharose); 37.9 (HMP–Sepharose); 27.2 (AHMP–HEMA); and 39.9 (AHMP–DMAA). The stability constants of the insoluble iron(III) complexes on the resins were compared with those of the corresponding soluble iron(III) complexes. The effect of immobilization on the constants was discussed, and it was found that a higher hydrophilicity and stability of a resin resulted in an increase of the stability constant, whereas steric hindrance decreased the stability constant. © 1995 John Wiley & Sons, Inc.
Cyclopolymerization of dodecanidiol dimethacrylate and identification of polymer structure
Authors: Huang Junlian , Hu Youqian , Ruyter I. Eystein
Published: April 2003

Dodecanidiol dimethacrylate (DDMA) was polymerized by a cyclization mechanism in low monomer concentration (0.075–0.5 mol/L) and high AIBN concentration (0.44−1.76 × 10−2). The linear soluble polymer was formed even if the conversion of DDMA was as high as 25.6%. The glass transition temperature of cyclized polyDDMA (PDDMA) is about 4.5°C, which is 65°C higher than its homolog—poly(dodecyl methacrylate). The structure of the polymer was established by infrared and 1H‐ and 13C‐NMR spectroscopy. The head‐to‐tail contents in cyclized PDDMA, i.e., the formation of a 20‐membered ring, is predominant compared with those of head‐to‐head contents of a 19‐membered ring. © 1995 John Wiley & Sons, Inc.
Determination of ZnO dispersion in rubber compounds
Authors: Jurkowski B. , Koczorowska E. , Goraczko W. , Manuszak J.
Published: April 2003

It was found that radioisotopic methods can be adapted for analysis of ZnO dispersion in rubber compounds. This method is characterized by a sensitivity of 10−6 g ZnO/1 g rubber compound. This fact enables application of this method in technological and research problems. © 1995 John Wiley & Sons, Inc.
Entry pressure and elastic behavior of a branched polyethylene
Authors: Chohan R. K.
Published: April 2003

Die entry pressures and elastic parameters derived from these have been determined for one low‐density polyethylene (LDPE) at four temperatures using three dies having different entry angles. The elongational viscosity shows a somewhat different behavior with respect to temperature than the shear viscosity. Mostly the elastic parameters show a temperature‐independent relation to the shear stress but only if the data at the lowest temperature used (130°C) are ignored. The latter data show that the material is much more elastic at this temperature than at higher ones; this is so even when the temperature is increased by only 20°C, after which any further increase gives negligible difference in elasticity. This behavior is probably due to a structural difference which may be a result of increased crosslink sites created by flow‐induced crystallization. © 1995 John Wiley & Sons, Inc.
Reprocessing of liquid‐crystal polymers: Effects on structure and mechanical properties
Authors: Bastida S. , Eguiazábal J. I. , Nazábal J.
Published: April 2003

The effects of reprocessing by successive injection molding cycles on the structure and properties of two thermotropic liquid‐crystal polymers (LCPs), namely Rodrun and Vectra, were analyzed. Reprocessing produces a clear decrease in the melt viscosity of both LCPs. This is attributed to molecular weight decreases as a consequence of chemical reactions. The reactions produced chain scission in both LCPs and new products in the case of Vectra. This gave rise to modifications in the crystalline behavior of Vectra that did not take place in the case of Rodrun. All these facts lead to, with the exception of the modulus of elasticity of Rodrun, an overall decrease in properties, more marked in the case of Vectra. © 1995 John Wiley & Sons, Inc.
Determination of filler content in thermoplastic composites by FTIR analysis
Authors: Fuad M. Y. Ahmad , Yaakob I. , Rusli O. , Ishak Z. A. Mohd , Omar A. K. Mohd
Published: April 2003

FTIR quantitative analytical method is described as an alternative technique for computation of the filler content in polypropylene composites. White rice husk ash (WRHA) was incorporated as a filler material into polypropylene homopolymer. Absorption peaks at 480, 621, and 790 cm−1 chosen for the quantitative analysis work have been shown to give good linearity with increasing filler contents. © 1995 John Wiley & Sons, Inc.
Rate of formation of polysulfides of 2‐bisbenzothiazole‐2‐2′‐disulfide in the presence of sulfur and 2‐mercaptobenzothiazole
Authors: Gradwell M. H. S. , Morgan B. , McGill W. J.
Published: April 2003

2‐Bisbenzothiazole‐2,2′‐disulfide was heated isothermally with and without sulfur at temperatures between 130 and 178°C for various periods of time and the mixture analyzed by high‐pressure liquid chromatography (HPLC). 2‐Bisbenzothiazole‐2,2′‐monosulfide formed rapidly and 2‐bisbenzothiazole‐2,2′‐polysulfides after an induction period of about 5 min. Polysulfides of higher sulfur rank are formed by the sequential addition of sulfur atoms. 2‐Mercaptobenzothiazole catalyzes the formation of 2‐bisbenzothiazole‐2,2′‐polysulfides and elimates the induction period. Mechanisms for the decomposition of 2‐bisbenzothiazole‐2,2′‐disulfide and the catalytic role of 2‐mercaptobenzothiazole are proposed. © 1995 John Wiley & Sons, Inc.
Deformation behavior of polypropylene/polyamide blends
Authors: Rösch Joachim , Mülhaupt Rolf
Published: April 2003

In recent years, blend technologies have been developed to modify mechanical properties of polypropylene by dispersing discrete stress‐concentrating polyamide microparticles in the continuous polypropylene matrix. The work presented here is concerned with the examination of fundamental relationships between blend morphologies and mechanical properties, especially plastic deformation mechanisms at high strain. Polyamide‐6, polyamide‐12, polyamide‐12 plasticized with N‐butyl‐phenylsulfonamide, and polyamide‐6 in situ embedded in a shell composed of polyamide‐36,6 have been used as blend components in polypropylene blends containing 30 vol % of these polyamides. For modification of interfacial adhesion, maleic‐anhydride‐grafted‐polypropylene has been added. When the yield stresses of polyamide and polypropylene are matched, large elongations at break of the resulting blends can be achieved. The influence of crazing, voiding, and shear yielding has been elucidated by transmission electron microscopic analysis of strained blend samples. © 1995 John Wiley & Sons, Inc.
Properties of biomedical pressure‐sensitive adhesive copolymer films with pendant monosaccharides
Authors: Miyata Takashi , Morizane Mayumi , Nakamae Katsuhiko , Okumura Masakazu , Kinomura Keisuke
Published: April 2003

Glucosyloxyethyl methacrylate (GEMA) was copolymerized with butyl acrylate (BA) for the preparation of a biomedical pressure‐sensitive adhesive with pendant monosaccharides, for possible use in medical applications. The measurements of 180° peel strength, ball tack, and holding power for the GEMA–BA copolymer films revealed that the film at the GEMA content of 5 mol % has excellent pressure‐sensitive adhesive properties. Protein adsorption onto the GEMA–BA copolymer film hardly occurred due to very low interfacial free energy between its surface and water. Release profiles of vitamin B12 from the GEMA–BA copolymer film suggests that it is useful as a material for a transdermal therapeutic system. © 1995 John Wiley & Sons, Inc.
Performance improvement of glass‐fiber‐reinforced polystyrene composite using a surface modifier. I. Synthesis and characterization of poly(γ‐MPS‐co‐styrene)
Authors: Jang Jyongsik , Lee Junyeob , Jeong Jongkoo
Published: April 2003

Poly(γ‐MPS‐co‐styrene), as a surface modifier of glass‐fiber‐reinforced polystyrene composite, was synthesized to improve the adhesion between glass fiber and polystyrene matrix. The copolymerization was carried out using AIBN as the initiator at 70°C. The reactivity ratios of γ‐MPS and styrene were determined by the Finemann–Ross method. The result was r1 (styrene) = 0.10, r2 (γ‐MPS) = 0.86. Judging from these results, the copolymerization of γ‐MPS and styrene was azeotropic copolymerization and the synthesized copolymer was a random one. Thermal stability of the copolymer was improved as the content of silane in the copolymer was increased and the glass transition temperature decreased. The surface modified glass fiber was investigated with Fourier transform infrared spectroscopy (FTIR). The glass fiber surface was effectively modified with the copolymer. © 1995 John Wiley & Sons, Inc.
Synthesis of reactive oxazolyl styrene–acrylonitrile copolymers
Authors: Hseih D. T. , Schulz D. N. , Peiffer D. G.
Published: April 2003

A series of oxazoline‐modified styrene–acrylonitrile (SAN) copolymers was prepared through the reaction of amino alcohols onto preformed SAN copolymers. Consequently, a variety of reactive copolymers were synthesized. The major focus of this study was to examine the influence of reaction conditions, i.e., the nature of the catalyst and amino alcohol structure, on reactivity. The ability to incorporate oxazoline groups onto preformed polymers is dependent on whether homogeneous reaction conditions are met. For example, the use of nonreactive solubilizing agents, i.e., cosolvent, is effective. However, optimum conditions are obtained when the catalyst is completely soluble in the reaction mixture containing the amino alcohol and SAN copolymer. With these restrictions, zinc stearate is quite effective. Our results show that controlled and reproducible levels of oxazoline can be incorporated (typically at a rate of 2 mol %/h) up to high levels. These results are general and therefore are applicable to a wide variety of nitrile‐containing polymers. © 1995 John Wiley & Sons, Inc.
Studies on functionality distribution of extractable sol from HTPB–isocyanate gumstock
Authors: Panicker Sreelatha S. , Ninan K. N.
Published: April 2003

Hydroxyl‐terminated polybutadiene (HTPB), even when cured with stoichiometric quantities of toluene diisocyanate (TDI), gives some extractable sol from the gumstock and the sol is believed to be predominantly due to the nonfunctional molecules in the HTPB. However, the present work shows that the molecules in the sol contain hydroxyl functional groups whose nature was established by hydrolyzing the urethane present in the sol and by analyzing the functionality distribution of the molecules so generated from the sol. The sol contains chain‐extending difunctional and crosslinking tri‐ and polyfunctional molecules; however, the concentration of the former is more, when compared to the original HTPB. All three types of primary hydroxyl groups of HTPB (G, H, and V) are also present in the sol. While there is a reduction in the G‐type hydroxyl in the sol, there is no major difference in the cis, trans, and vinyl contents of the backbone of the sol and HTPB. The molecules in the sol have been excluded from the crosslinked network, not only because of the lack of their functionality alone, but also as a result of network imperfections which are an integral part of nonlinear polymerization reactions. © 1995 John Wiley & Sons, Inc.
Flow properties at elevated temperatures and clarity of HSPAN gel–water dispersions
Authors: Hardin Richard A. , Burmeister Louis C.
Published: April 2003

Dispersions of hydrolyzed‐starch–polyacrylonitrile (HSPAN) gel and distilled water underwent permanent diminuntion of room‐temperature viscosity after maintenance above a threshold temperature of 75°C for periods of several weeks. Below the threshold temperature, viscosity measured at room temperature was unaffected. Above the threshold temperature, the final room‐temperature viscosity exponentially varied as the inverse absolute temperature, and the viscosity decreased with increasing temperature. The HSPAN gel–distilled water dispersions exhibited both yield stress and velocity slip at a solid boundary, but the latter was not present at low shearing stresses. The former inhibited natural convection in a vertical slot with an imposed horizontal temperature difference. Clarity of the dispersions was demonstrated by a character‐visibility test. Deaerating the distilled water by boiling before mixing with HSPAN gel improved the clarity of the resulting dispersion by eliminating the formation of bubbles at elevated temperature. © 1995 John Wiley & Sons, Inc.
Extrusion effects on the mechanical properties of Agar
Authors: Rakow Allen L. , Belfiore Laurence A.
Published: April 2003

The mechanical properties of extruded mixtures of Agar and water were measured for two formulations under slightly different extrusion conditions. The extrudate exhibits high tensile strength when moisture content is 30 wt% and very high elongation (> 2000%) when moisture content is 60 wt %. Electron micrographs of extruded samples at these extremes support the mechanical data. © 1995 John Wiley & Sons, Inc.
The surface relaxation of glow discharge‐treated silicone polymer
Authors: Kuznetsov A. Yu. , Bagryansky V. A. , Petrov A. K.
Published: April 2003

The samples of radiationally linked vinyl (1%) methylsilicone elastomer (silicone) were modified in glow‐discharge air plasma. Surface relaxation was studied by the data on equilibrium contact angles. The degree of relaxation is shown to increase with increasing plasma treatment duration, probably due to the increase in the destruction degree of the spatial network of chemical bonds in the silicone surface layer. The changes in the chemical composition of the surface were controlled using attenuated total reflectance‐infrared spectroscopy. Plasma treatment leads to increase of the polar component of the polymer surface energy and increase of the absorption bands of carboxyl and hydroxyl groups in its spectra. These characteristics disappear when the samples are kept in the open air and can be recovered by putting them into water. Such behavior can be explained by the fact that the polar oxygen‐containing groups, forming on the surface due to plasma treatment, pass inside the polymer. Considering the adhesion properties of modified silicone, its biocompatibility was predicted. © 1995 John Wiley & Sons, Inc.
Compatibility in polymer/plasticizer blend system: Thermal, X‐ray, and dynamic mechanical studies of PMMA/PTBF blends
Authors: Kalkar A. K. , Parkhi Purnima S.
Published: April 2003

Differential thermal and dynamic mechanical analysis (DTA and DMA) were carried out on the blend system of atactic poly(methyl methacrylate) (PMMA) with poly(p‐t‐butyl phenol formaldehyde) (PTBF). In both the techniques, the PMMA/PTBF blend system exhibited a composition‐dependent, single glass‐transition temperature, indicating miscibility. The blends exhibited composition‐dependent morphology dominated by induced cluster formation of PMMA as a separate phase in blends. The DTA scans of blens exhibited broad melting endotherms. Also, in DMA, apart from the main relaxation (tan δ), the system showed an additional high‐temperature relaxation (Tu), indicating the presence of a separate phase. In addition, wide‐angle X‐ray diffraction (WAXD), Fourier‐transform infrared (FTIR) spectroscopy, and sonic pulse propagation measurements provide evidence for the formation of PMMA clusters in the bulk PMMA/PTBF blends. The mechanical behavior of the blends is discussed in terms of the variations in shape and magnitude of tan δ, E″, and E″ curves. It is concluded that PTBF acts as a compatible plasticizer in PMMA/PTBF blends and, because of changed morphology, improveds the elongation of blend films compared to pure PMMA. © 1995 John Wiley & Sons, Inc.
On‐line gas chromatography and densimetry to obtain partial conversions of both monomers in emulsion copolymerization
Authors: Noël Lilian F. J. , Brouwer Eric C. P. , Van Herk Alex M. , German Anton L.
Published: April 2003

Monitoring and controlling composition drift is an important issue in emulsion copolymerization. Due to the heterogeneity of the polymerization system often combined with nonideal kinetics, predicting copolymer composition and changes in feed composition as a function of time is not straightforward. Therefore, accurate and fast on‐line determination of partial conversions of the separate monomers is a key to understanding and controlling the copolymer system studied. For this reason on‐line densimetry, resulting in overall weight conversion, is combined with on‐line gas chromatography, resulting in the overall ratios of the residual monomer. Combining these two on‐line data gives the partial conversion of each monomer as a function of time without the need of an internal standard. The determination of partial conversion of monomers in batch emulsion copolymerization from on‐line gas chromatography and on‐line densimetry is illustrated for the monomer system methyl acrylate‐vinyl acetate. © 1995 John Wiley & Sons, Inc.
High‐impact poly(ethylene terephthalate) blends
Authors: Penco M. , Pastorino M. A. , Occhiello E. , Garbassi F. , Braglia R. , Giannotta G.
Published: April 2003

Rubbers of different kind were tested as toughening agents of poly(ethylene terephthalate) (PET), noting significant morphological and mechanical differences. In particular, good results were obtained by using an ethylene–ethyl acrylate–glycidyl methacrylate copolymer. The resulting blend evidenced good particle distribution, and the latter was related to chemical interactions between the rubber epoxy groups and PET terminal groups, including the effect of low molecular weight and polymeric amine catalysts, and to extrusion conditions. © 1995 John Wiley & Sons, Inc.
The synthesis and properties of a cation‐exchange resin prepared by the pyrolysis of starch in the presence of phytic acid
Authors: Lehrfeld Jacob , Baker Frederick L.
Published: April 2003

A black charcoal‐like material having cation exchange and adsorption properties was prepared by the controlled pyrolysis of starch in the presence of a commercial phytic acid solution. Resins with binding capacities of 0.7–5.7 meq/g of calcium were prepared by varying the phytic acid to starch ratio, the temperature, or the duration of heating of the reaction mixture. SEM photomicrographs of some of these new materials showed that they are composed of particles similar in size and shape to the starting starch granules. These resins also removed atrazine from aqueous solutions. © 1995 John Wiley & Sons, Inc.

This article is a US Government work and , as such, is in the public domain in the United States of America.
Modification of cellulose in conditions of plastic flow under pressure
Authors: Rogovina S. Z. , Zhorin V. A. , Enikolopian N. S.
Published: April 2003

The search for new ecologically pure production processes for numerous cellulose derivatives is important technologically. It is well known that under shear deformation in solid substances, various physical and chemical effects may take place. The possibility of production of some cellulose derivatives, such as carboxymethylcellulose and cellulose acetates, is shown under conditions of joint action of high pressure and shear deformation at room temperature. The formation of an easily hydrolyzed fraction of cellulose under these conditions is also investigated. This reaction procedure is of great practical interest, as it makes it possible to reduce the consumption of reagents and to carry out the process in the absent of solvents. © 1995 John Wiley & Sons, Inc.