bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of crosslinking monomers on the performance of electron beam‐induced biodegradable Bionolle–rubber blends
Authors: Khan Mubarak A. , Ali K. M. Idriss , Yoshii F. , Makuuchi K.
Published: October 2004

To find out the better crosslinking monomer for vulcanization of natural rubber under electron beam (EB) radiation, the dry rubber was masticated with different polyfunctional monomers like TMPTA, NVP, and ethylene glycol diacrylate of different numbers of CH2 CH2O group, such as 1G, 3G, 7G, and 10 G. The masticated films were irradiated with different doses under EB at 10 kGy/pass. The highest tensile strength (25 MPa) of the rubber was observed in the presence of TMPTA (3phr) at 150 kGy dose. The gel content of the rubber increased with an increase of dose. Bionolle was mixed with the masticated rubber containing 3 phr TMPTA at different proportions; films of these blends along with Bionolle were irradiated under EB with different doses. The concentration of rubber in Bionolle and radiation dose were optimized. The elastomer with 5% masticated showed the highest tensile strength (62 MPa). The gel content of the blends was found to increase with an increase of radiation dose as well as rubber concentration in Bionolle. The elastomers or blends were found to possess good thermal properties. The elastomers exhibited a much lower loss of tensile strength due to the thermal aging compared with pure Bionolle. The elastomers sustained their original shape for 300 min at 180°C, whereas Bionolle sustained its shape for only 3 min at 120°C under the same load (50 g). Among all the elastomers, 5% rubber containing elastomer was found to be better in all respects. It was observed from scanning electron microscopy and differential scanning calorimetry studies that 5% rubber is well mixed with Bionolle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 799–807, 2001
Synthesis and properties of novel poly(phthalazinone ether ketone ketone)
Authors: Liu Y. J. , Jian X. G. , Liu S. J.
Published: October 2004

A novel poly(phthalazinone ether ketone ketone) was prepared via the nucleophilic substitution polycondensation of bis‐1,4‐(4‐chlorobenzoyl)benzene and 4‐(4‐hydroxyphenyl)‐2,3‐phthalazin‐1‐one. The synthesized polymer exhibited high glass‐transition temperature, excellent thermooxidative properties, and fair rheological properties. The polymer was soluble in some polar solvents. Electronic friction and membrane properties are also discussed. The results indicate that the polymer falls in the class of high temperature resistance engineering plastics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 823–826, 2001
Effect of amino‐polycarbonate on the curing kinetics and morphology of epoxy resin
Authors: Hao Dongmei , Tang Xiaozhen , Wang Xinling , Luo Yinpei
Published: October 2004

The curing kinetics and the glass transition behavior of amino‐polycarbonate with diglycidyl ether of bisphenol‐A epoxy resin systems were studied by differential scanning calorimetry (DSC). The ASTM E‐698 method was chosen to determine the kinetics parameters of the curing reaction, including the activation energy, preexponential factor, rate constant, and 60‐min half‐life temperature. The amino‐polycarbonate was able to accelerate the curing reaction, reduce the apparent active energy, and decrease Tg of the systems. A homogeneous amino‐polycarbonate/epoxy resin network was observed in scanning electron microscopy (SEM) pictures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 833–838, 2001
Fabrication of deodorizing fabric by grafting of metal phthalocyanine derivative onto nonwoven polypropylene fabric
Authors: Cho Dong Lyun , Choi Chang Nam , Kim Hyun Jin , Kim Ae Kyoung , Go Jin‐Hwan
Published: October 2004

Fabrication of deodorizing fabric was tried by grafting metal phthalocyanine derivative, a catalytic deodorant, onto polypropylene (PP) nonwoven fabric. Fe(III)‐4,4′,4″,4‴‐tetra carboxamide phthalocyanine (Fe‐TCMP) was synthesized. The Fe‐TCMP showed high‐deodorizing performance when tested for the elimination of 2‐mercaptoethanol, an index material for bad‐smelling compounds. The Fe‐TCMP was converted to Fe(III)‐4,4′,4″,4‴‐tetracarboxylic acid phthalocyanine (Fe‐TCAP) by hydrolysis to have carboxyl groups. It was chemically grafted on the surface of PP nonwoven fabric, which was surface modified to have amine groups with diaminocyclohexane (DACH) plasma. Such fabricated deodorizing fabric showed high‐deodorizing performance for 2‐mercaptoethanol. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 839–846, 2001
Investigations of the copolymerization of acrylonitrile with vinyl acetate and sodium methallylsulfonate
Authors: Qiu Gao , Tang Zhi‐Lian , Huang Nan‐Xun , Chen Hong‐Jun
Published: October 2004

The bulk copolymerizations of acrylonitrile (AN) with vinyl acetate (VAc) initiated by azobisisobutyronitrile (AIBN) and the suspension copolymerization of AN with VAc and sodium methallylsulfonate (SMAS) in water with a Na2S2O5–Na2ClO3 redox initiator system at 65°C, were investigated. The copolymer compositions were determined by 1H‐NMR. The reactivity ratios (γs) for the two copolymerization systems were determined analytically, based on Mayo–Lewis equation, by fitting the calculated curves with the experimental data. The γs for the AN and VAc bulk copolymerization were found to be γ12 = 2.85 and γ21 = 0.11. The values of the apparent γs for the suspension copolymerization of AN, VAc, and SMAS were as follows: γ12 = 3.58, γ21 = 0.39, γ13 = 1.45, γ31 = 0, γ23 = 0.92, and the rate constant ratio R3 = k31/k32 = 0.04. A simulated result produced with the obtained γs agreed fairly well with experimental data of bulk copolymerization in a batch reactor. The apparent γs obtained were also successfully used to analyze the results of suspension polymerization in a continuous pilot reactor.© 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 854–860, 2001
Modification of epoxy resin with kaolin as a toughening agent
Authors: Fellahi S. , Chikhi N. , Bakar M.
Published: October 2004

Epoxy resins are widely used as high‐performance thermosetting resins for many industrial applications, but unfortunately, some are characterized by a relatively low toughness. In this respect, many efforts have been made to improve the toughness of cured epoxy resins by the introduction of rigid particles, reactive rubbers, interpenetrating polymer networks, and thermoplastics within the matrix. In this work, kaolin as a modifier was added at different contents to improve the toughness of diglycidyl ether of bisphenol A epoxy resin with polyamino‐imidazoline as a curing agent. The chemical reactions suspected of taking place during the modification of the epoxy resin were monitored and evaluated with Fourier transform infrared spectroscopy. The glass‐transition temperature (Tg) was measured with differential scanning calorimetry. The mechanical behavior of the modified epoxy resin was evaluated in terms of the Izod impact strength (IS), the critical stress intensity factor (KIC), and tensile properties at different modifier contents. Scanning electron microscopy (SEM) was used to elucidate the mechanisms of deformation and toughening in addition to other morphological features. Finally, the adhesive properties of the modified epoxy resin were measured in terms of tensile shear strength (TSS). With the addition of kaolin, the reactivity test revealed that the gel time and temperature, exotherm peak, and cure time were reduced. Infrared spectra showed the existence of a chemical reaction between kaolin and the epoxy resin. The presence of kaolin caused a steady decrease in Tg by about 10°C until 15‐phr kaolin was reached prior to leveling off. Most of the tensile properties attained a peak at an approximately 10‐phr kaolin content where the toughening reached its maximum. The modulus increased linearly from 1.85 to 2.7 GPa with increasing kaolin content. For both notched and unnotched specimens, a twofold increase in Izod IS was obtained by the addition of just 10‐phr kaolin compared to the unfilled resin. On the addition of kaolin, the Izod IS varied from 0.85 to 1.53 kJ/m2 for notched specimens and from 4.19 to 8.32 kJ/m2 for unnotched specimens, whereas KIC varied from 0.91 to 2.63 MPa m1/2 with increasing kaolin content. The adhesive properties, evaluated in terms of TSS, increased from 9.14 to 15.02 MPa. SEM analysis revealed that the prevailing toughening mechanism for the epoxy resin under consideration was localized plastic shear yielding induced by the presence of kaolin particles associated with crack pinning. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 861–878, 2001
Molecularly imprinted polyacrylic acid containing multiple recognition sites for steroids
Authors: Sreenivasan K.
Published: October 2004

The preparation and evaluation of a molecularly imprinted polymer (MIP) based on acrylic acid and ethylene glycol dimethacrylate containing multiple recognition sites for steroids is discussed. The ability of the polymer to bind simultaneously three steroids, namely cholesterol, testosterone, and hydrocortisone, is demonstrated. These types of novel MIPs with multiple binding sites could be useful in the design of sensing elements capable of detecting more components at a time. Such polymers could also be used as stationary phases in chromatography with broad separation potential as well as sorbents in solid‐phase extraction. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 889–893, 2001
Two‐stage swelling of acrylamide gels: A photon transmission study
Authors: Pekcan Önder , Kara Selim
Published: October 2004

Acrylamide gels were prepared from acrylamide (AAm) with various N,N′‐methylenebis(acrylamide) (Bis) contents by free‐radical crosslinking copolymerization (FCC) in water and dried before used for swelling experiments. Photon transmission measurements were performed using a UV‐visible (UVV) spectrometer during the swelling of polyacrylamide gels. Transmitted light intensity Itr increased linearly at very early times when acrylamide gels were immersed in water, then decreased continuously as swelling time increased. The behavior of Itr was modeled assuming two‐stage swelling mechanisms for the swelling acrylamide gels. The increase in Itr at early times was quantified using a linear diffusion model and a linear relaxation constant k0 was measured. The decrease in Itr was modeled using the Li–Tanaka equation, from which time constants τ1 and cooperative diffusion coefficients D0 were determined for acrylamide gels with varying Bis content. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 894–906, 2001
Soap‐free seeded emulsion copolymerization of MMA onto PU‐A and their properties
Authors: Zhang Hong Tao , Guan Rong , Yin Zhao Hui , Lin Liu Lan
Published: October 2004

The polyurethane acrylate (PU‐A) containing double bond and COOH group was synthesized by stepwise reaction of 2,4‐toluene diisocyanate (TDI), polyetherdiol (PPG), dimethylolpropionic acid (DMPA), and 2‐hydroxpropyl acrylate (HPA), and the PU‐A was neutralized with triethylamine (TEA) and self‐emulsified in water to form the PU‐A emulsion seed. Adding methyl methacrylate (MMA) into PU‐A seed, the seeded emulsion copolymerization of MMA onto PU‐A seed had been carried out at 80°C under the soap‐free condition to obtain anionic latex of P(UA‐MMA). The kinetic behavior of the seeded emulsion copolymerization, the MMA grafting ratio, and the crosslinking copolymer were investigated. IR spectra showed that it did form the P(UA‐MMA) copolymer. The measurements revealed that the structure of the P(UA‐MMA) copolymer, its latex properties and the cast film were significantly influenced by the amounts of HPA, DMPA, and MMA. The experimental results indicated that with DMPA increased, the particle size of P(UA‐MMA) latex decreased, but the tensile strength of its cast film increased. Adding a small amount of HPA, it could improve the tensile strength of the cast film. With MMA content increased, the distribution of the particle size of P(UA‐MMA) latex became narrow, whereas under certain amount of MMA, the tensile strength of the cast film was enhanced. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 941–947, 2001
Effect of radiation on the friction‐wear properties of polyetherketone with a cardo group
Authors: Tian Nong , Li Tongsheng , Liu Xujun , Liu Weimin
Published: October 2004

We studied the effect of radiation on the friction‐wear properties of polyetherketone with a cardo group (PEK‐C) with a MM‐200 model friction and wear tester. We found that radiation could improve the friction‐wear properties of PEK‐C to a certain degree. The friction coefficient and wear rate of PEK‐C decreased as the radiation dose increased from 5 × 104 to 1 × 107 Gy. Scanning electron microscopy results revealed that the size of wear debris of unirradiated PEK‐C was larger than that of irradiated PEK‐C. The worn surface of unirradiated PEK‐C showed plough marks, whereas the worn surface of irradiated PEK‐C did not show plough marks; its surface was quite smooth. With the frictional couple of a carbon steel ring and an irradiated PEK‐C block, a relatively uniform and coherent transfer film was formed on the ring surface. It was inferred that the transfer film contributed largely to the decreased friction coefficient and wear rate of the irradiated PEK‐C. An IR spectrum showed that no significant chemical change took place when the PEK‐C sample was irradiated. Thermal analysis results showed that radiation changed the thermal properties of PEK‐C, therefore, its friction‐wear properties changed at the same time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 962–967, 2001
High‐performance polymer films. III. Preparation and characterization
Authors: Khatua Sankar C. , Maiti Sukumar
Published: October 2004

A series of polyimide and copolyimide films were prepared by film casting, drying, and thermal imidization from the respective precursor poly(amic acid) (PAA) and copoly(amic acid) solutions derived from two dianhydrides, pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA), and two diamines, 4,4′‐oxydianiline (ODA) and a proprietary aromatic diamine (PD) as monomers. Depending on the solution's inherent viscosity value (molecular weight) and the nature of the polymer chains (derived from rigid or flexible monomers), precursor poly(amic acid) and copoly(amic acid) solution concentrations of 8–12% (w/w) were found to be suitable for the preparation of good quality polyimide/copolyimide films. The recovery of film toughness and creasability from the brittleness at the intermediate temperature of the cure cycle depended not only on the molecular weight of the precursor poly(amic acids)/copoly(amic acids) but also on their chain flexibility. The poly(amic acid) derived from both rigid dianhydride and diamine practically gave rise to a brittle film of polyimide even after curing to 360°C. The resulting polyimide and copolyimide films were compared with Du Pont's Kapton H film. The density of the films was in the range 1.39–1.42 g/cm3. The thickness of most of the films was in the range 20–30 μm. The HPF 3 film, based on PMDA–PD, appeared to be highly colored (reddish brown), and the HPF 2 film, based on BTDA–ODA, had the lightest yellow coloring among the films in this investigation, including Kapton H film. HPF 2, HPF 6, and HPF 8 films were more amorphous than the other films. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 976–988, 2001
Infrared dichroism and birefringence studies of silica‐filled styrene–butadiene rubbers
Authors: Bokobza L. , Ladouce L. , Bomal Y. , Amram B.
Published: October 2004

Infrared and birefringence measurements are used to characterize the orientational behavior of silica‐filled styrene–butadiene copolymers. The orientational data are correlated with the results of equilibrium swelling measurements. On the other hand, the role played by a silane couling agent bis(3‐triethoxysilylpropyl)tetrasulfide (TESPT), or “Si69”) on rubber/silica system is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1006–1012;2001
Surface‐active properties of hydrophobized derivatives of lignosulfonates: Effect of structure of organosilicon modifier
Authors: Telysheva G. , Dizhbite T. , Paegle E. , Shapatin A. , Demidov I.
Published: October 2004

An investigation of regularities of surface‐tension alterations in the aqueous solutions of lignosulfonate and aluminum‐containing organosilicon oligomer (olygoheterosiloxanolates) reaction mixtures revealed that modification with oligomers can be used for the regulation of the surface activity of lignosulfonates. High surface activity not only in acidic, but also in neutral and alkali media, is achieved using oligomers which consist of ethylsesquioxane and diethylsiloxane links. In this case, increasing hydrophobicity compensates the negative effects (increase of solubility and the Coulomb repulsion) of ionization of lignosulfonate acidic groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1013–1020, 2001
Copolymerization behavior of 3‐isopropenyl‐α,α‐dimethylbenzylamine and a preliminary evaluation of the copolymers in thermoset coatings
Authors: Trumbo D. L. , Mote B. E. , Trevino A. S. , van den Brink M.
Published: October 2004

The title monomer was synthesized from 3‐isopropenyl‐α,α‐dimethylbenzyl isocyanate in a significantly better yield than was previously reported. 3‐Isopropenyl‐α,α‐dimethylbenzylamine proved incapable of homopolymerization using free‐radical initiation but readily copolymerized with a variety of commonly available monomers under free‐radical conditions. Films of some of the copolymers were prepared and crosslinked using a variety of multifunctional epoxy compounds. The films had good solvent resistance, high hardness, and good gloss. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1030–1039;2001
Raman microimaging study of interfacial profiles of hydrogels
Authors: Zerda T. W. , Appel Rainer , Hu Zhibing
Published: October 2004

A Raman microimaging technique was used to directly observe the interfacial profile between N‐isopropylacrylamide (NIPA) and polyacrylamide (PAAM) hydrogels in water. The joined hydrogels are called bigels and are synthesized by penetrating the PAAM gel into a part of the NIPA gel network. The bigel strip contains about 97 wt % water at room temperature. The study reveals how different manufacturing parameters, such as the drying time of the NIPA substrate and the diffusion time of the PAAM pregel solution into the NIPA layer, influence the properties and extent of the bigel interface. The interface becomes thicker with increased drying time. Specifically, the average interfacial thickness of the interface after 2 h of drying is about 28 μm, but increases to 156 μm after 16 h of drying time. The extent of the interface is independent of the PAAM diffusion time. The penetration of the PAAM pregel solution into the pores of the NIPA gel is completed in less than 30 min. The topography of the surface can be well characterized by a Gaussian function with the correlation length describing the size of the interfacial region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1040–1046;2001
Progressive morphology development to produce multilayer films and interpenetrating blends by chaotic mixing
Authors: Kwon O. , Zumbrunnen D. A.
Published: October 2004

Chaotic mixing of immiscible binary components was recently used in a continuous flow process to obtain extruded films with very many internal layers. Where interfacial tension is small, individual layer thicknesses can be only tens of nanometers and many thousands of continuous or broken layers can be formed. Such materials are both novel and potentially important. In this study, multilayer film formation and breakup were investigated systematically by using a batch chaotic mixer to better understand the more industrially relevant continuous flow counterpart. Polystyrene (PS) and low‐density polyethylene (LDPE) were used as a model binary system with appreciable interfacial tension such that comparatively thicker layers and larger breakup bodies were formed and more readily examined. The multilayer film morphology developed progressively as chaotic mixing continued and was thereby amenable to control and optimization with regard to layer thickness and number. Blends with single or dual phase continuity and structured droplet distributions were found to be important derivative morphologies upon layer breakup. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1569–1579, 2001
Degree of crosslinked cotton cellulose with prereacted DMDHEU–AA
Authors: Chen Jui‐Chin , Yao Wei‐Hua , Chen Chien‐Hsin , Chen Cheng‐Chi
Published: October 2004

Dimethyloldihydroxyethyleneurea (DMDHEU) and acrylic acid (AA) were used to synthesize the dimethyloldihydroxyethyleneurea–acrylic acid product (DMDHEU–AA, mole ratios of DMDHEU/AA = 1/0, 1/1, and 1/2, respectively). Cotton fabrics were treated with the various prereacted DMDHEU–AA products by changing resin concentrations in the bath. We found that the dry crease recovery angle (DCRA) and wet crease recovery angle (WCRA) of the treated fabrics increased with the increase of acrylic acid in the prereacted DMDHEU–AA at the same value of resin concentration in the bath, whereas the tensile strength retention (TSR) showed the inverse tendency. For a given value of number of crosslinks per anhydroglucose unit (CL/AGU), the DCRA and WCRA values of the DMDHEU–AA‐treated fabrics were higher than those for DMDHEU‐treated fabrics. Additionally, agent distribution and the reaction between –COOH of the crosslinking agent and cellulose molecule were also investigated in this study. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1580–1586, 2001
Monitoring water uptake of polyurethanes by in situ fluorescence technique
Authors: Hakala K. , Vatanparast R. , Vuorimaa E. , Lemmetyinen H.
Published: October 2004

The water uptake of three polyurethane adhesives was studied by an in situ fluorescence method applying extrinsic fluorescent probes. The measurements were made in water immersion at 50 and 80°C, and in water vapor at 50°C. An intensity ratio method was applied, in which ratios of the highest and lowest intensity changes in the fluorescence emission bands were used to determine the amount of water sorbed in the polymer films. The ratio method was used to compare the fluorescence data with those obtained by a conventional gravimetric method. Comparable results were obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1593–1599, 2001
Synthesis and properties of PMR type poly(benzimidazopyrrolone‐imide)s
Authors: Li Y. F. , Hu A. J. , Wang X. C. , Gao S. Q. , Yang S. Y.
Published: October 2004

PMR type poly(benzimidazopyrrolone‐imide) or poly(pyrrolone‐imide) (PPI) matrix resin was synthesized using the diethyl ester of 4,4′‐(hexafluoroisopropylidene)diphthalic acid (6FDE), 3,3′‐diaminobenzidine, para‐phenylenediamine, and monoethyl ester of cis‐5‐norbornene‐endo‐2,3‐dicarboxylic acid (NE) in anhydrous ethyl alcohol with N‐methylpyrrolidone. The homogeneous matrix resin solution (40–50% solid) was stable for a storage period of 2 weeks and showed good adhesion with carbon fibers, which ensured production of prepregs. The chemical and thermal processes in the polycondensation of the monomeric reactant mixture were monitored by Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscopy, etc. Thermosetting PPI as well as short carbon fiber‐reinforced polymer composites was accomplished at optimal thermal curing conditions. The polymer materials, after postcuring, showed excellent thermal stability, with an initial decomposition temperature > 540°C. Results of MDA experiments indicate that the materials showed > 70–80% retention of the storage modulus at 400°C and glass transition temperatures as high as 440–451°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1600–1608, 2001
Photopolymerization of hyperbranched aliphatic acrylated poly(amide ester). I. Synthesis and properties
Authors: Lin De , Shi Wen‐Fang , Nie Kang‐Ming , Zhang Yu‐Chuan
Published: October 2004

The hyperbranched aliphatic poly(amide ester) (HAPAE) was synthesized based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid prepared by the reaction of succinic anhydride with diethanol amine, as an AB2 monomer (repeating unit), and with 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol, as a core molecule, using acid catalysis. The second generation of the product was characterized by measuring dynamic viscosity, which decreased sharply with the increase in frequency. The product exhibits relative thermal stability as analyzed by thermogravimetry in a nitrogen atmosphere. The glass transition temperature, determined by differential scanning calorimetry, is −27 °C. The molar mass was measured by vapor pressure osmometry. The polydispersity, measured by size exclusion chromatography, is 2.16. Dynamic mechanical thermal analyses were performed to characterize the thermal properties of the ultraviolet‐cured films of the acrylate‐modified HAPAE. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1630–1636, 2001
Photopolymerizaton of hyperbranched aliphatic acrylated poly(amide ester). II. Photopolymerization kinetics
Authors: Lin De , Kou Huiguang , Shi Wen‐Fang , Yuan Hui‐Ya , Chen Yong‐Lie
Published: October 2004

A hyperbranched aliphatic poly(amide ester) ending with hydroxyl groups based on 4‐N,N‐di(2‐hydroxy ethyl)‐4‐ketobutyric acid (DKBA) and 2‐ethyl‐2‐(hydroxymethyl)‐1,3‐propanediol (TMP) was modified with acryloyl chloride, resulting in a radiation‐curable, hyperbranched acrylated poly(amide ester). This hyperbranched polymer was characterized with respect to ultraviolet cure rate, unsaturation conversion, and mechanical properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1637–1641, 2001
Studies of dielectric characteristics and surface energies of spin‐coated polyimide films
Authors: Qu Wen‐Li , Ko Tze‐Man
Published: October 2004

A two‐step method, that is, polyamic acid formation with subsequent curing, was used to synthesize six kinds of polyimides. Dielectric constants and surface energies were investigated to determine the nature of the fluorinated and nonfluorinated polyimides. The dielectric constant decreased from 3.3 (at 100 kHz) for PMDA/ODA to 2.6 (at 100 kHz) for 6FDA/4,4′‐6F when the fluorine content increased from 0 to 30.7 wt %. Simultaneously, the water contact angle increased from 65° for PMDA/ODA to 78° for 6FDA/4,4′‐6F. Experimental results indicated that fluorinated polyimides contained a lower dielectric constant with improved water resistance. The surface energy values obtained from experiments agreed well with Holmes' correlation between surface energy and dielectric constant. The surface energies and dielectric constants were significantly affected by the polymer backbone structures, especially by the fluorination effect. Therefore, by choosing the appropriate monomers, polyimides of low dielectric constants with hydrophobic surfaces could be obtained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1642–1652, 2001
Synthesis of poly(vinyl acetate)‐graft‐polystyrene and application to preparation of porous membranes
Authors: Park Eun‐Soo , Yoon Jin‐San
Published: October 2004

Poly(vinyl acetate)–TEMPO (PVAc–TEMPO) macroinitiators were synthesized by bulk polymerization of vinyl acetate in the presence of benzoyl peroxide (BPO) followed by termination with 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO). Radicals were mainly transferred to the acetoxy methyl groups in PVAc during the polymerization. The PVAc–TEMPO macroinitiators had several TEMPO‐dormant sites and styrene bulk polymerization with the macroinitiators produced poly(vinyl acetate)‐graft‐polystyrene (PVAc‐g‐PS). All the TEMPO‐dormant sites of PVAc–TEMPO macroinitiators participated in the styrene polymerization with almost equal reactivity. Methanolysis of PVAc‐g‐PS broke the PS branches apart from the PVAc backbone chains. Hydrophobic or hydrophilic porous membranes with controlled pore size could be prepared by removing the PVAc domains or the PS domains from the graft copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1658–1667, 2001
Kinetic study of emulsion copolymerization of ethyl methacrylate/lauryl methacrylate in propylene glycol, stabilized with poly(ethylene oxide)–block–polystyrene–block–poly(ethylene oxide) triblock copolymer
Authors: You Xiaorong , Dimonie Victoria L. , Klein Andrew
Published: October 2004

The kinetics of emulsion copolymerization of ethyl methacrylate (EMA)/lauryl methacrylate (LMA) in propylene glycol is very similar to the emulsion copolymerizations of water‐soluble monomers in water because of the high solubility of EMA/LMA in propylene glycol. The initial rate of polymerization depends only on initiator concentration and is not affected by either monomer concentration or stabilizer concentration. The overall rate of polymerization is only slightly dependent on monomer concentration and stabilizer concentration and is independent of initiator concentration. The final particle number density increases with increasing amount of stabilizer and decreases with increasing monomer concentration. The total surface area increases with stabilizer concentration and is not governed by either initiator concentration or monomer concentration. Homogeneous nucleation is the dominant mechanism of particle nucleation, as shown by the kinetic data on seeded polymerization and monomer partition behavior. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1691–1704, 2001
Effect of polymer loading on the electrical and thermodynamic properties in relation to gas chromatographic applications
Authors: El‐Naggar A. Y. , Turky G. M.
Published: October 2004

Different layers, 5, 10, 15, and 25% (w/W), of the three studied polyethylene glycols (PEGs) having different molecular weights, 600, 4000, and 20,000, were used for coating on chromosorb pink acid washed (P AW). The polarity and selectivity of the prepared packing columns and their thermodynamic parameters were determined via inverse gas chromatography. The effect of polymer‐layer thickness on the polarity was studied dielectrically. The dependence of specific retention volume, enthalpy, and entropy upon the loading of polymer on support were also studied. In all investigated polymers, the loads 5 and 10% deactivate the support surface, resulting in a decrease in its capacitances, which reflects the polarity. The loads 15% PEG20,000 and 25% PEG4000 can elute n‐alcohols and exhibit high efficiency of separation; however, in the case of PEG600, loading has to exceed 25% to be sufficient for eluting n‐alcohols. The lower thickness of the coated polymers was preferred for good separation of saturated hydrocarbons and also for cyclohexane and aromatic hydrocarbons. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1709–1717, 2001
Effect of coupling agents on the mechanical properties of fly ash/polyester particulate composites
Authors: Guhanathan S. , Devi M. Saroja , Murugesan V.
Published: October 2004

Fly ash (FA)/general purpose unsaturated polyester resin (GPR) particulate composites were made. The effect of the surface treatment of FA with two different silane coupling agents (CAs) on the mechanical properties, such as the tensile, flexural, compressive, and impact strengths and hardness, of FA–GPR composites were studied. The properties of FA–CA–GPR were also compared with that of GPR and CaCO3–GPR. An enhancement in the tensile, flexural, compressive, and impact strengths and a decrease in the tensile and flexural moduli were observed when FA was surface treated with CA. Hardness also increases with CA‐treated FA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1755–1760, 2001
Strengthening blends of poly(lactic acid) and starch with methylenediphenyl diisocyanate
Authors: Wang Hua , Sun Xiuzhi , Seib Paul
Published: October 2004

Poly(lactic acid) (PLA) is a biodegradable polymer, but its applications are limited by its high cost. Blending granular starch with PLA reduces the cost, but the blend has poor strength properties. In this study, a 55/45 (w/w) mixture of PLA (weight‐average molecular weight = 120,000 Da) and dried wheat starch was blended thermally in an intensive mixer with or without a low level of methylenediphenyl diisocyanate (MDI). Blends with MDI had enhanced mechanical properties that could be explained by the in situ formation of a block copolymer acting as a compatibilizer. Scanning electron micrographs showed reduced interfacial tension between the two phases. The presence of MDI also enhanced the mechanical properties of the blend at temperatures above the glass‐transition temperature. Water uptakes by the PLA/starch blends with and without MDI did not differ. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1761–1767, 2001
Multivariate statistical analysis of mid‐infrared spectra for the online monitoring of 2‐ethylhexyl acrylate/styrene emulsion copolymerization
Authors: Stavropoulos Y. , Kammona O. , Chatzi E. G. , Kiparissides C.
Published: October 2004

This article describes the application of multivariate statistical process control techniques to a series of mid‐infrared spectra collected online from a styrene/2‐ethylhexyl acrylate emulsion copolymerization process. Principal component analysis of the mid‐infrared spectral data indicated that in situ monitoring of the complex copolymerization process was feasible in the spectral region of interest. It was also observed that projection to latent structures or partial least squares (PLS) could be used for the effective indirect online prediction of individual monomer conversions and copolymer compositions over a substantial range of process operating conditions. A combination of the developed PLS methodology with a mid‐infrared attenuated total reflection probe proved to be an effective tool for the efficient online characterization of polymer quality, thereby overcoming the lack of robust online conversion and composition measuring devices. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1776–1787, 2001
Development of high‐strength fibers from aliphatic polyketones by melt spinning and drawing
Authors: Gupta P. , Schulte J. T. , Flood J. E. , Spruiell J. E.
Published: October 2004

We have investigated the formation of high‐strength, high‐modulus fibers from four aliphatic polyketone resins. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other three were terpolymers containing up to 6 mol % propylene. The mechanical properties were measured as a function of processing conditions, and the structures of the filaments were characterized using birefringence, WAXS, SAXS, SEM, and thermal analysis. Fibers formed from all resins develop very high molecular orientations and a microfibrillar structure. Fibers having room temperature tenacities as high as 10 gpd (∼1.1 GPa) were obtained. Tensile moduli reached values as high as 120 gpd (∼13 GPa). The melting point of the fibers was primarily dependent on the composition of the resin, while the maximum strength and modulus were largely determined by the maximum draw ratio achieved. The maximum draw ratio achieved in the present experiments was greater for the terpolymers than for the copolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1794–1815, 2001
Proton nuclear magnetic resonance spectroscopic analysis of polypeptide models of the elastic network phase of wool fibers: Defining Cys‐residues capable of serving as a crosslinking agent
Authors: Liff Mark I.
Published: October 2004

A polymer network structure of the matrix phase of wool fibers was modeled by polypeptide systems containing fragments of high sulfur (HS) proteins with Cys‐residues oxidized in pairs to form a network. Our previous studies have shown that Cys‐residues belonging to the two characteristic repeats (dipeptide and pentapeptide) from HS proteins of the matrix have a low propensity to serve as crosslinks of the matrix. This study reveals that Cys‐residues located outside the two repeats have a higher propensity to serve as crosslinks of the network than Cys‐residues belonging to the repeats. Effective crosslinking by the nonrepeat Cys‐residues, on the one hand, and formation of intrarepeat loops by the residues of the repeats, on the other hand, can explain well‐known macroscopic properties of the matrix phase, such as its elasticity and ability to swell in solvents. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1824–1828, 2001
Replacement of virgin rubbers by waste ground vulcanizates in blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene fluoride terpolymer
Authors: Ghosh Arun , Antony P. , Bhattacharya A. K. , Bhowmick A. K. , De S. K.
Published: October 2004

This study reports the results of investigations on blends of silicone rubber and fluororubber based on tetrafluoroethylene/propylene/vinylidene fluoride terpolymer and the effects of replacement of silicone rubber and/or fluororubber in their 50/50 blend by the respective vulcanizate powders of known compositions. To simulate the aging condition of factory wastes, the silicone rubber or fluororubber vulcanizates were aged for 72 h at 200°C and then converted into powder by mechanical grinding. The fluororubber vulcanizate powder (FVP), mostly spherical in shape with average diameter varying between 2 and 10 μm, exists in a highly aggregated state displaying chainlike structures that, however, break down during blending with virgin rubbers. The silicone rubber vulcanizate powder (SVP) is irregular in shape, with larger particles in the range of 30–100 μm, and the smaller particles exist in highly aggregated chainlike structures, as in the case of FVP, which break down during milling to mostly spherical particles of 2–10 μm in diameter. Measurements of physical properties reveal that the blends of silicone rubber and fluororubber are technologically compatible. SEM photomicrographs of THF‐etched samples show the biphasic structure of the blends, in which the fluororubber forms the dispersed phase in a continuous silicone rubber matrix of lower viscosity. Replacement of silicone rubber in the 50/50 silicone rubber/fluororubber blend by its vulcanizate powder (SVP) increases the Mooney viscosity, but replacement of fluororubber in the blend by its vulcanizate powder (FVP) has little effect on the Mooney viscosity. Monsanto rheometric studies reveal that replacement of silicone rubber by SVP or fluororubber by FVP in the 50/50 silicone rubber/fluororubber blend increases the minimum rheometric torque but decreases the maximum torque, and the effect is more pronounced in the case of SVP. Furthermore, the replacement of silicone rubber in the blend by SVP causes a decline in the physical properties (25% replacement causing about 10% decline in properties, for example), whereas even 75% replacement of fluororubber by FVP has little effect on the physical properties. When both silicone rubber and fluororubber are partially replaced by SVP and FVP in the same blend, properties of the resulting blend composition are controlled more by SVP incorporation, whereas fluororubber replacement has only a marginal effect on blend properties. It is evident from dynamic mechanical spectra that the blends are immiscible in all compositions and addition of SVP or FVP does not affect the glass–rubber transitions of the constituent polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2326–2341, 2001
Synthesis and characterization of novel biodegradable polymers composed of hydroxycinnamic acid and D,L‐lactic acid
Authors: Matsusaki Michiya , Kishida Akio , Stainton Neil , Ansell Christopher W. G. , Akashi Mitsuru
Published: October 2004

D,L‐Lactic acid (DLLA) was polycondensed with 4‐hydroxycinnamic acid (4HCA), a derivative of cinnamic acid, to prepare a novel functional biodegradable polymer. The polymer was prepared using two different methods, the solvent method, which used acetic anhydride as the solvent, and the direct method. White and brown‐colored copolymers were obtained by these two methods, respectively. 1H‐NMR spectroscopy and UV‐visible spectroscopy revealed that the double bond of 4HCA was almost completely destroyed when the copolymer was prepared by the direct method. On the other hand, copolymers in which the double bond was preserved in the 4HCA–DLLA copolymer were successfully obtained using the solvent method. The solubility of the copolymers obtained by the solvent method in organic solvent was poor. When the copolymer was prepared under a 4HCA:DLLA ratio of 20:80 using the solvent method, the resulting copolymer had high solubility in organic solvents and the double bond was preserved. Moreover, it was confirmed that the 4HCA–DLLA copolymer synthesized by the solvent method was both photoreactive and biodegradable. The 4HCA–DLLA copolymer is expected to be used as basic material for tissue engineering and drug delivery systems, in addition to applications as an orthopedic matrix and a degradable plastic. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2357–2364, 2001
In situ compatibilization of polystyrene and polyurethane blends by using poly(styrene‐co‐maleic anhydride) as reactive compatibilizer
Authors: Cassu Silvana Navarro , Felisberti Maria Isabel
Published: October 2004

Blends of polystyrene (PS) and polyurethane (PU) elastomer were obtained by melt mixing, using poly(styrene‐co‐maleic anhydride) (SMA) containing 7 wt % of maleic anhydride groups as a reactive compatibilizer. Polyurethanes containing polyester flexible segments, PU‐es, and polyether flexible segments, PU‐et, were used. These polyurethanes were crosslinked with dicumyl peroxide or sulfur to improve their mechanical properties. The anhydride groups of SMA can react with the PU groups and form an in situ graft copolymer at the interface of the blends during their preparation. The rheological behavior was accompanied by torque versus time curves and an increase in the torque during the melt mixing was observed for all the reactive blends, indicating the occurrence of a reaction. Solubility tests, gel permeation chromatography, and scanning electronic microscopy confirmed the formation of a graft copolymer generated in situ during the melt blending. These results also indicate that this graft copolymer contains CC bond between SMA and PU chains. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2514–2524, 2001
Synthesis and characterization of the biodegradable copolymers from succinic acid and adipic acid with 1,4‐butanediol
Authors: Ahn B. D. , Kim S. H. , Kim Y. H. , Yang J. S.
Published: October 2004

Biodegradable homopolyesters such as poly(butylene succinate) (PBSU) and poly(butylene adipate) (PBAD) and copolyesters such as poly(butylene succinate‐co‐butylene adipate) (PBSA) were synthesized, respectively, from succinic acid (SA) and adipic acid (AA) with 1,4‐butanediol through a two‐step process of esterification and deglycolization. The polyester compositions and physical properties of both homopolyesters and copolyesters were investigated by 1H– and 13C–NMR, DSC, GPC, WAXD, and optical polarizing microscopy. The melting point (Tm) of these copolyesters decreased gradually as the contents of butylene adipate increased and the glass‐transition temperature (Tg) of these copolyesters decreased linearly as the contents of the adipoyl unit increased. PBSA copolyesters showed two types of XRD patterns of PBSU and PBAD homopolyesters. Furthermore, the biodegradation and hydrolytic degradation of the high molecular weight PBSU homopolyester, PBAD homopolyester, and PBSA copolyesters were investigated in the composting soil and NH4Cl aqueous solutions at a pH level of 10.6. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2808–2826, 2001
Synthesis and pyrolysis of polysilazane precursors containing linear–cyclic structures for Si/N/C‐based ceramics
Authors: Xu Caihong , Liu Chunjuan , Zheng Zhimin , Li Yongming , Zhang Zhijie , Yang Shiyan , Xie Zemin
Published: October 2004

A new kind of polysilazane precursor containing linear–cyclic structure was synthesized from the de‐lithium chloride condensation reaction of hexamethylcyclotrisilazane lithium salts (D) and 1,3‐dichlorotetraorganodisilazanes [(ClR1R2Si)2NH]. Pyrolyses of these precursors and some comparable linear polysilazanes were carried out at 900 °C in nitrogen. The results indicated that the existence of linear–cyclic structure in precursors provided relatively crosslinked or branched structures, which were helpful for improving ceramic yields. The precursor containing a linear–cyclic structure as well as reactive vinyl groups gave the highest pyrolytic yields. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2827–2831, 2001
Effects of polymer solvents on the performance of cellulose acetate membranes in methanol/methyl tertiary butyl ether separation
Authors: Tabe‐Mohammadi Abdulreza , Villaluenga Juan P. Garcia , Kim Hyo J. , Chan Theresa , Rauw Vanessa
Published: October 2004

The performances of cellulose acetate membranes prepared with casting solutions, with acetone, dimethylformamide (DMF), and N‐methylpyrrolidone (NMP) as solvents, were studied in a series of methanol/methyl tertiary butyl ether separation experiments. The flux and selectivity of the membrane samples were affected by the type of solvent used to prepare the casting solution. The sample with DMF consistently gave the highest selectivity and lowest flux, followed by the samples with NMP and acetone. The differences in the performances were attributed to the effects of the volatility and evaporation rates of the solvents. Scanning electron microscopy and atomic force microscopy techniques were used for comparing the morphologies of the membranes. In addition, we used Raman spectroscopy as a novel technique to study the sorption selectivities of the membrane samples prepared with the three different solvents. In a parallel study, the relation between the polymer concentration in the casting solution and the morphology and performance of the membrane samples was studied. Under similar preparation conditions, the morphology of the membrane changed from being porous to being dense when the membrane was prepared with casting solutions with increasing polymer concentration. Also, the selectivity increased and the permeability decreased with increasing polymer concentration in the casting solution. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2882–2895, 2001
Formation of hollow fibers in the melt‐spinning process
Authors: Rwei Syang‐Peng
Published: October 2004

This article reports an investigation of the formation of hollow fibers in a melt‐spinning process. Experimental results indicate that die swelling is largely responsible for a negative effect on hole formation. The factors that positively affect die swelling, including a decrease in temperature, a decrease in capillary length, and an increase in shear rate, are thus not recommended for the spinning of hollow fibers. For vinyl‐type polymers such as polypropylene, in which the apparent elasticity leads to serious die swelling, the formation of hollow fibers is more complex than that of a typical condensation polymer. Our results further demonstrate that when hollow fibers are being made in a variety of shapes (but of the same denier), spinning a polygonal hollow fiber is significantly more unstable than spinning a circular one. Moreover, an asymmetric bridge along the polygonal contour leads to a melt twist and interrupts the entire spinning process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2896–2902, 2001