bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a simplified relationship between uniaxial creep, stress relaxation, and constant strain‐rate results for viscoelastic polymeric materials
Authors: Sudduth Richard D.
Published: October 2004

This publication introduces a new mathematical model to describe a definitive relationship between constant strain‐rate, creep, and stress‐relaxation analysis for viscoelastic polymeric compounds. This new concept is especially significant since it adequately describes all the important characteristics of both creep and stress relaxation in the same model. In particular, all three phases of creep (i.e., primary, secondary, and tertiary) can be described adequately using this model. This new model for polymeric materials also indicates that yielding for constant strain‐rate measurements and the inception of tertiary creep appear to be directly related and may, in fact, be manifestations of the same phenomena. The initial buildup of stress followed by the drop off in stress as a function of time for stress relaxation is also adequately described. This new formulation approach also offers a reasonably simple process in which to shift from a constant strain‐rate configuration to a creep calculation or stress‐relaxation configuration without changing formulation considerations. Most importantly, this model can be used to make a transition from one of these stress‐configuration modes to another without stress or strain discontinuities. It is hoped that this analysis approach will open new doors for the design of plastic products for both short‐term and long‐term applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 527–540, 2001
Synthesis and air separation of soluble terpolymers from Aniline, Toluidine, and Xylidine
Authors: Li Xin‐Gui , Huang Mei‐Rong , Zhu Li‐Hua , Yang Yuliang
Published: October 2004

A series of terpolymers were synthesized by oxidative polymerization of aniline, o‐toluidine, and 2,3‐xylidine with three monomer ratios using ammonium persulfate as an oxidant in two acidic media. The yield and intrinsic viscosity of the terpolymers were studied by changing the polymerization temperature and medium. The resulting terpolymers were characterized by 1H–NMR, wide‐angle X‐ray diffraction, differential scanning calorimetry, thermogravimetry, and constant pressure‐variable volume methods. The results showed that the terpolymers are amorphous and exhibit enhanced solubility, high thermostability, and high char yield, greater than 35 wt % at 900°C in nitrogen. A blend membrane of the terpolymer with ethyl cellulose shows good air‐separation ability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 790–798, 2001
Studies on the composites of cellulose triacetate (prepared from sugar cane pulp) and gelatin
Authors: Rajini R. , Venkateswarlu U. , Rose C. , Sastry T. P.
Published: October 2004

Sugarcane waste (bagasse) which is hitherto discarded as a waste at sugarcane parlors and jaggery units was recovered and cellulose triacetate (CTA) was prepared from the same, after isolation of cellulose. Using this CTA, CTA–gelatin composites were prepared. The materials prepared (i.e., sugarcane cellulose, CTA, CTA–gelatin composites) were characterized for their mechanical properties, water absorption capacity, infrared spectroscopy, and scanning electron microscopy. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 847–853, 2001
Synthesis and characterization of an isocyanurate–oxazolidone polymer: Effect of stoichiometry
Authors: Chian K. S. , Yi S.
Published: October 2004

Isocyanurate–oxazolidone polymers were synthesized by using various reactant stoichiometry of a diglycidyl ether of bisphenol‐A (DGEBA) and a polymeric diphenyl methane diisocyanate (pMDI). The reaction was catalyzed by tris‐2,4,6‐dimethylaminoethylphenol (Ancamine K54). The effects of stoichiometry that the reaction had on the molecular structure and mechanical and thermomechanical properties were evaluated. Two main structures obtained from the reaction of DGEBA with pMDI, namely isocyanurate and oxazolidone, were clearly shown by Fourier transformed infrared spectroscopy (FTIR) analyses. It was found that the amount of DGEBA present determines the amount of oxazolidone formed. Where excess DGEBA was used, structural transformation reaction from isocyanurate to oxazolidone was observed. The amount of pMDI, on the other hand, influenced the amount of isocyanurate structure formed. As the relative amounts of isocyanurate and oxazolidone contents changed with stoichiometry of the reactants, the effects on the crosslink density in the samples were clearly shown by both mechanical and thermomechanical measurements. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 879–888, 2001
Hydrolysis of aromatic heterocyclic polymers in high temperature water. I. Hydrolysis of polyphenyl‐1,2,4‐triazine
Authors: Yi Xiao‐Bing , Wu Guo‐Shi , Lu Feng‐Cai , Tang Au‐Chin
Published: October 2004

The hydrolytic behaviors of polyphenyl‐1,2,4‐triazine (As–PPT) at high temperatures were investigated both experimentally and theoretically. The hydrolytic experiments of As–PPT film and a reasonably designed model compound for the polymer were carried out in distilled water at 250°C/3.97 MPa under N2atmosphere, respectively. The hydrolytic reactions were monitored by FTIR and UV‐Vis spectra, and their hydrolysates were identified by FTIR, HPLC, and MS. The results confirmed that the two reactions gave the same major hydrolysate, terephthalic acid. In addition, the electronic structure of its model compound, given by ab initio calculation at the 4‐31G level, indicated that the triazine ring is the hydrolytically active part at which the N atoms are to be protonated. On the basis of these results, a hydrolytic mechanism is proposed, which suggests that the cleavage of one CN bond takes place, primarily on the triazine rings, followed by a gradual rupture of the polymer chain and the formation of the intermediate terephthalonitrile, the further hydrolysis of which produces terephthalic acid.© 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82;907–915;2001
Synthesis and properties of polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane
Authors: Zhou N. , Zhang Z. J. , Xu C. H. , Xie Z. M.
Published: October 2004

A new kind of polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane was prepared by the anionic polymerization with a “seed solution” as initiator. The synthesis of monomers N,N′‐bis(hydroxydiphenylsilyl)tetraphenylcyclodisilazane (BHPTPC), N,N′‐bis(chlorodiphenylsilyl)tetraphenylcyclodisilazane (BCPTPC), and 1,3‐dichloro‐1,1,3,3‐tetraphenyldisilazane (DCTPS) are all reported in this study. The synthesized polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane was characterized by 1H–NMR, 29Si–NMR, gel permeation chromatography (GPC), and intrinsic viscosity. The thermal stability of the polysiloxane was studied by isothermal gravimetric analysis (IGA). The results demonstrated that the synthesized polysiloxane containing N,N′‐bis(diphenylsilyl)tetraphenylcyclodisilazane had excellent thermal stability. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 929–933, 2001
Study of microbial polyhydroxyalkanoates using two‐dimensional Fourier‐transform infrared correlation spectroscopy
Authors: Wu Qiong , Tian Ge , Sun Suqin , Noda Isao , Chen Guo‐Qiang
Published: October 2004

The premelting behavior of bacterially synthesized polyester poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate), abbreviated as P(HB‐co‐HHx), was investigated by two‐dimensional Fourier‐transform infrared (2D FTIR) correlation spectroscopy. The temperature‐dependent dynamic spectra were measured over a temperature range of 25–300°C. We focused our study on the thermally induced intensity fluctuations of bands for CO (1700–1760 cm−1), CH (2910–3010 cm−1) and COC groups (1220–1310 cm−1) stretching vibrations. Changes of crystalline conformation due to the thermal perturbation could be detected by the intensity and location variations of those characteristic bands responding to the variations of dipole moments. 2D correlation analysis indicated that the appearance of fully amorphous component did not happen simultaneously with the disappearance of crystalline component, suggesting that there was an intermediate state between ordered crystalline and amorphous states in P(HB‐co‐HHx). © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 934–940, 2001
Solution thermodynamics of the dextran/methoxy ethylene glycol system
Authors: Güner Ali , Çatiker Efkan
Published: October 2004

The main thermodynamic parameters were evaluated for the dextran/methoxy ethylene glycol (MEG) system by viscosity measurements at 25, 30, 35, 40, and 45°C. The long‐range and short‐range interaction parameters were determined by extrapolation methods, i.e, Kurata‐Stockmayer‐Fixman, Berry, and Inagaki‐Suzuki‐Kurata equations. Calculated values, as well as the unperturbed root‐mean‐square end‐to‐end distance and hydrodynamic expansion factor, were interpreted mainly on the basis of hydrogen‐bond formation between polymer segments and dextran/MEG molecules in solution. The thermodynamic interaction parameter was also evaluated for the same system. The theta temperatures were obtained from the temperature dependence of the interaction parameter, dependence of (1/2‐χ) and the second virial coefficient in the temperature interval of 25 and 45°C for the system and quite a good accordance was indicated with the calculated values evaluated via extrapolation and interpolation methods. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 948–953, 2001
Study of the actions of BTEX compounds on polypyrrole film as a gas sensor
Authors: Lin C. W. , Liu S. S. , Hwang B. J.
Published: October 2004

Polypyrrole (PPy) thin films were prepared electrochemically at a constant potential. Gas‐sensing behaviors, including reproducibility, sensitivity, and response time to various benzene, toluene, ethylbenzene, and xylene (BTEX) compound concentrations, were investigated. BTEX compounds were found to be able to compensate for the doping level of PPy and, hence, decrease the conductivity of PPy on exposure to them. A reasonable reproducibility of the resistance change (ΔR) was obtained. The sensitivity for each compound was 2.3 mω/ppm (benzene), 0.4 mω/ppm (toluene), 8.3 mω/ppm (ethylbenzene), and 2.9 mω/ppm (xylene). An adsorption model correlated well with the experimental results and was used to interpret the sensing behaviors. The parameters of this model, including the adsorption equilibrium constant and the ΔR caused by a pseudomonolayer of the detecting layer {[m(r1 − r0)]/n, where m is the number of active sites on the pseudomonolayer; r1 and r0 are the site resistances when the site is vacant and occupied, respectively; and n is the thickness of the film}, were determined. According to the parameters, toluene vapor had the most prominent effect in undoping PPy film but the poorest affinity to the active sites of the film. On the other hand, ethylbenzene showed the highest affinity to PPy film compared to the other BTEX compounds and consequently led to the highest sensitivity for such a sensor. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 954–961, 2001
Effect of sintering on surface chemistry and surface energy of pigmented latex coatings
Authors: Al‐Turaif H. , Lepoutre P.
Published: October 2004

Drying in the absence of water (sintering) of pigmented coatings made of styrene–butadiene (SB) latex and kaolin clay at different levels of pigmentation was investigated. As found from X‐ray photoelectron spectroscopy, sintered coatings showed a higher SB area percent on the surface than did latex with a high glass‐transition temperature (Tg) and dried at room temperature. This was a result of latex spreading at the surface. Sintering the high‐Tg coatings that were dried at room temperature caused a decrease in the surface energy. Drying in the presence of water (wet coalescing) was compared to drying in the absence of water (sintering). Even though sintered coatings were more porous and had higher gloss, no significant difference was found in the SB/clay ratio at the surface or in the surface energy above the critical pigment volume concentration (CPVC). However, at and below CPVC, the sintering process yielded a higher SB content at the surface and a lower surface energy than the wet‐coalescing process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 968–975, 2001
Optimization of physical and mechanical properties of rubber compounds by a response surface methodological approach
Authors: Sridhar V. , Prasad K. , Choe S. , Kundu P. P.
Published: October 2004

Response surface methodology was used for optimizing the ratio of vegetable oil and carbon black and occluded volume fraction of rubber in the compound. Central composite design for two variables was chosen as the experimental design. The data obtained from measurement of properties was fitted as a two variable second‐order equation, and were plotted as contours using software developed from MATLAB v.5.1. From contours it is observed that at the ratio of 0.06 of vegetable oil and carbon black, there is maximum coupling, and a further increment in vegetable oil and carbon black ratio shows less coupling and more plasticizing effect. The ultimate failure properties like tensile and tear strength and elongation decreases with an increase in occluded volume fraction, reaches a minima at the central region, followed by an increase, whereas 300% modulus and hardness decreases throughout.© 2001 John Wiley & Sons, Inc, J Appl Polym Sci 82: 997‐1005, 2001
Study of cryostructuration of polymer systems. XX. Foamed poly(vinyl alcohol) cryogels
Authors: Lozinsky Vladimir I. , Damshkaln Lilija G.
Published: October 2004

Foamed poly(vinyl alcohol) (PVA) cryogels, which are formed as a result of freeze–thaw treatment of whipped PVA water solutions (polymer with MW of 69,000 Da and DD ∼99 mol % was used), were obtained and their properties were studied. The rheological characteristics and macrostructure of these gel materials were controlled by the same factors as for the ordinary nonfoamed PVA cryogels (initial polymer concentration and freezing–thawing regimes) and also by the conditions of generation of fluid PVA foams. The study of the kinetics of the freeze–thaw‐induced gel formation of these foams revealed that the temperature dependence of the efficiency of cryotropic gelation showed a maximum at about −1.5°C. The presence of low molecular weight admixtures in the initial polymer solution appears to be a rather important factor because the admixtures were capable of decreasing the stability of fluid PVA foams and weakening both foamed and nonfoamed cryogel samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1609–1619, 2001
Blend fibers of polyacrylonitrile and water‐soluble chitosan derivative prepared from sodium thiocyanate solution
Authors: Nam Chang‐Woo , Kim Young Ho , Ko Sohk Won
Published: October 2004

A water‐soluble chitosan derivative of N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTCC), synthesized by the reaction of chitosan and glycidyltrimethyl ammonium chloride, and polyacrylonitrile (PAN) were blended using 46% (w/w) NaSCN aqueous solution as a common solvent. The total polymer concentration of blend solution was fixed at 12% (w/w), and the relative composition of PAN/HTCC in the blend solution varied from 0/100 to 80/20 by weight. The PAN/HTCC blend fibers with the appropriate physical property were prepared by a wet spinning and drawing process. The effect of HTCC content on the structural change, miscibility, and ability to be dyed of the blend fibers was investigated. The optical and scanning electron microscopic observation gave no indication of phase separation up to 20% HTCC content. Differential scanning calorimetry and dynamic mechanical measurements of the blend fibers show single glass transition temperatures that increase with increasing blend ratio of HTCC. All the experimental results exhibit that the blends are miscible on the molecular scale. The blend fibers could be dyed with an acid dye. This enhanced ability of the blend fibers to be dyed with acid dyes could be useful for one‐step dyeing when mixed with other fibers, such as wool and nylon. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1620–1629, 2001
Preparation of amorphous poly(ethylene terephthalate) from U‐polymer via a copolymerization process
Authors: Liu Su‐Huai , Zhang Shu‐Fan , Qi Zong‐Neng , Zhang Guang‐Li , Zhang Hong‐Zhi
Published: October 2004

U‐Polymer, a kind of polyarylate, was synthesized by interfacial polycondensation method with terephthaloyl chloride (TPC), isophthaloyl chloride (IPC), and bisphenol A (BPA) as raw materials. The structure of the U‐Polymer was characterized by IR and 1H–NMR spectra. Then, an amorphous poly(ethylene terephthalate) (APET) was prepared with the introduction of the U‐Polymer to the PET sequence to improve thermal and mechanical behaviors of PET via the polymerization process. The structure and property of the APET were characterized by DSC and DMA. The results showed that the APET exhibits amorphism, transparency, higher glass‐transition temperature (Tg), and higher storage modulus than that of PET. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1653–1657, 2001
Surface modification of low‐density polyethylene (LDPE) film and improvement of adhesion between evaporated copper metal film and LDPE
Authors: Kong Ju‐Shik , Lee Dong‐Jin , Kim Han‐Do
Published: October 2004

To improve the interfacial adhesion between evaporated copper film and low‐density polyethylene (LDPE) film, the surface of LDPE films was modified by treating with chromic acid [K2Cr2O7/H2O/H2SO4 (4.4/7.1/88.5)]/oxygen plasma. Chromic‐acid‐etched LDPE was exposed to oxygen plasma to achieve a higher content of polar groups on the LDPE surface. We investigated the effect of the treatment time of chromic acid in the range of 1–60 min at 70°C and oxygen plasma in the range of 30–90 sec on the extent of polar groups created on the LDPE. We also investigated the surface topography of and water contact angle on the LDPE film surface, mechanical properties of the LDPE film, and adhesion strength of the evaporated copper metal film to the LDPE film surface. IR and electron spectroscopy for chemical analysis revealed the introduction of polar groups on the modified LDPE film surface, which exhibited an improved contact angle and copper/LDPE adhesion. The number of polar groups and the surface roughness increased with increasing treatment time of chromic acid/plasma. Water contact angle significantly decreased with increasing treatment time of chromic acid/plasma. Combination treatment of oxygen plasma with chromic acid drastically decreased the contact angle. When the treatment times of chromic acid and oxygen plasma were greater than 10 min and 30 sec, respectively, the contact angle was below 20°. With an increasing treatment time of chromic acid, the tensile strength of the LDPE film decreased, and the film color changed after about 10 min and then became blackened after 30 min. With the scratch test, the adhesion between copper and LDPE was found to increase with an increasing treatment time of chromic acid/oxygen plasma. From these results, we found that the optimum treatment times with chromic acid and oxygen plasma were near 30 min and 30 sec, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1677–1690, 2001
Novel regenerated cellulose fibers from rice straw
Authors: Lim Sang Kyoo , Son Tae Won , Lee Dong Won , Park Bong Kuk , Cho Kyu Min
Published: October 2004

Regenerated cellulose fibers from rice straws with a diameter of 10 to 25 μm and initial modulus of 11 to 13 GPa were prepared by wet spinning in rice straw/N‐methylmorpholine‐N‐oxide (MMNO) solution. X‐ray diffraction analysis indicates that the rice straw regenerated fibers are classified as cellulose (II). This observation indicates a potential utility of rice straw as an alternative to wood pulp as a cellulose‐based fiber material. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1705–1708, 2001
Preparation of bipolar membranes. II
Authors: Hao Ji Hua , Yu Lixin , Chen Cuixian , Li Lin , Jiang Weijun
Published: October 2004

The bipolar multilayer membrane was prepared by a new technique. The interfacial layer and cation layer were formed by only one step. The anion and cation layers were made from the same material from which chloromethylated polysulfone was used as a basic material. The bipolar membranes were composed of a solvent‐resistant anion layer with crosslinking matrix by the reaction of chloromethylated polysulfone in DMF with diamine; an ultrathin interfacial layer from chloromethylated polysulfone solution in DMF, containing cation‐exchange resin and both quaternary and nonquaternary amine groups; and a cation layer from chloromethylated polysulfone dispersing cation resin powder. The prepared bipolar membrane exhibits a lower voltage drop over 100 mA/cm2 and stable performances at a long‐term operation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1733–1738, 2001
On the viscoelastic properties of poly(vinyl alcohol) and chemically crosslinked poly(vinyl alcohol)
Authors: Park Jun‐Seo , Park Jang‐Woo , Ruckenstein Eli
Published: October 2004

Poly(vinyl alcohol)(PVA) films chemically crosslinked with glutaraldehyde(GA) in the presence of HCl were prepared by casting from aqueous solutions. The PVA and PVA gels were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA); their swelling characteristics and tensile strength were also determined. The DSC results for the gels displayed depressions of the melting and crystallization temperatures, as well as a decrease of the heat of fusion, when compared to those of PVA free of crosslinker. The DMA analysis revealed that: (1) The glass transition temperature of the wet PVA was lower than that of the dry one, indicating that the water had a plasticizing effect. (2) The gels had a lower glass transition temperature than PVA. (3) The glass transition temperature of the wet gels increased with increasing crosslink density. Possible explanations are provided for these observations. Whereas the thermogravimetric curves of PVA exhibited a single degradation peak, two degradation peaks were detected for the crosslinked PVA. The wet PVA and PVA gels displayed lower tensile strengths and higher elongations than the dried ones. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1816–1823, 2001
Acylation of silk and wool with acid anhydrides and preparation of water‐repellent fibers
Authors: Arai T. , Freddi G. , Innocenti R. , Kaplan D. L. , Tsukada M.
Published: October 2004

Silk and wool fibers were acylated with two acid anhydrides, dodecenylsuccinic anhydride (DDSA) and octadecenylsuccinic anhydride (ODSA), at 75°C with N,N‐dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) as the solvent, the latter of which allowed higher weight gains to be reached. The weight gain and acyl content of wool was always higher than that of silk. Tensile properties of silk remained unchanged regardless of weight gain, whereas wool displayed a noticeably higher extensibility at high weight gain. Fine structural changes of acylated wool were detected by DSC analysis. Moisture regain and water retention of acylated silk and wool decreased significantly, whereas water repellency increased. SEM analysis showed the presence of foreign material firmly adherent to the surface of both silk and wool, whose amount increased with increasing weight gain. These deposits were attributed to the presence of the modifying agents at the fiber surface on the basis of the characteristic IR bands. The possible application of silk and wool fibers acylated with DDSA or ODSA for the preparation of water‐repellent textile materials is discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2832–2841, 2001
Structure of carboxylated acrylonitrile‐butadiene rubber (CNBR)–clay nanocomposites by co‐coagulating rubber latex and clay aqueous suspension
Authors: Wu You‐Ping , Zhang Li‐Qun , Wang Yi‐Qing , Liang Yi , Yu Ding‐Sheng
Published: October 2004

Carboxylated acrylonitrile‐butadiene rubber (CNBR)–clay mixtures were prepared by co‐coagulating rubber latex and clay aqueous suspension, then combining the mixtures with a rubber ingredient and vulcanizing by a traditional rubber mixing processing procedure. Transmission electron microscopy (TEM) showed that the silicate layers of clay were delaminated or intercalated with CNBR and dispersed in the CNBR matrix at a nanometer level during co‐coagulating. X‐ray diffraction indicated that the amount of CNBR intercalating between the layers increased with the increase of content of clay in CNBR, which is in contrast with the results of other studies. Some reasons were put forward for this discrepency. The aspect ratio (width/thickness) of the platelet inclusions was reduced and the silicate layers were aligned more orderly during the compounding operation on an open mill. The intercalated CNBR, on co‐coagulating, still remained within the interlayer space after curing. In these nanocomposites, the particles of silicate layers were dispersed at the nanometer level and the structure was a combination of delaminated and intercalated silicate layers dispersed in the continuous CNBR matrix. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2842–2848, 2001
Mechanochemical polymerization of styrene initiated by the grinding of quartz
Authors: Hasegawa Masahiro , Kimata Mitsumasa , Kobayashi Shun‐Itsu
Published: October 2004

The polymerization of styrene mechanochemically initiated by the wet grinding of quartz was attempted by using a vibrating ball mill with a laboratory scale. The effect of the grinding of quartz on the polymerization of the styrene was investigated by characterizing the polymer formed and the quartz ground. The results showed that styrene could also mechanochemically polymerize by the resulting active species of the grinding of quartz as well as methyl methacrylate. The polymerization was found closely related to the total surface area of the ground quartz. The molecular weight distributions of the polymer formed were not simply unimodal and remarkably broader than those of the methyl methacrylate. It was suggested that the polymerization of the styrene proceeded with a cationic active species from the experimental results and discussions. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2849–2855, 2001
Using field theory to measure surface resistivity of high‐resistance polymeric films
Authors: Tsai Peter P. , Bresee Randall R.
Published: October 2004

Theoretical expressions based on Ohm's law for field theory were derived to measure surface resistivity of high‐resistance polymer films using parallel plate and concentric circular electrodes. Experimental measurements of resistivity were compared to experimental measurements using conventional expressions based on Ohm's law for circuit theory. Expressions based on Ohm's law for circuit theory were found to be inadequate for measuring surface resistivity. The surface resistivity of high‐resistance films can be accurately measured if electric field theory is used to include the effects of electrode structure, if relative humidity (RH) and temperature are controlled, if the level of applied voltage is limited, and if the measuring system is shielded from extraneous electric and magnetic fields. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2856–2862, 2001
Encapsulation efficiency and release kinetics of solid and liquid pesticides through urea formaldehyde crosslinked starch, guar gum, and starch + guar gum matrices
Authors: Kumbar Sangamesh G. , Kulkarni Anandrao R. , Dave Ashok M. , Aminabhavi Tejraj M.
Published: October 2004

This article presents our preliminary experimental data on the release kinetics and encapsulation efficiency of urea formaldehyde (UF) crosslinked matrices of starch (St), guar gum (GG), and starch + guar gum (St + GG) for the controlled release of solid (chlorpyrifos) and liquid (neem seed oil) pesticides. The data reveal variable release rates in relation to the polymer type and especially the pesticide type. It is possible to slow the release rates of pesticides using cheaply available materials such as starch and guar gum. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2863–2866, 2001
Control of resin release from particleboards by gamma irradiation. I. Thermal decomposition behavior and structure morphology
Authors: El‐Naggar A. M. , Kandeel K. A. , Khafaga M. R. , Zahran A. H.
Published: October 2004

The release or emission of resins from pressed particleboards, modified through gamma radiation, was characterized in terms of the thermal decomposition (TGA) and structure morphology (SEM). Particleboards, based on some farm residues and some polymers as adhesives, were first made by thermal compression in a hot press at 120°C and subsequently exposed to various doses of gamma irradiation. In general, gamma irradiation improves the thermal stability of the particleboards regardless of the type of the farm residues or the type of adhesive. Meanwhile, the thermal stability was found to increase with increasing irradiation dose as shown by the percentage loss in weight at different decomposition temperatures and the temperatures of the maximum values of the rate of reaction. The results showed that the particleboards based on cotton or flax stalks and polystyrene (PS) displayed higher thermal stability than did those based on the epoxy resin (E150). The particleboards based on wood sawdust and the E150 resin showed higher thermal stability than did those based on PS. SEM observations of the fracture surfaces of the different particleboards give further support to the improvement in the thermal properties after exposure to gamma radiation. In this regard, the pores and distances between the base material were coated with radiation‐crosslinked or ‐grafted E150 resin, particularly in the case of wood sawdust boards. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2869–2881, 2001
Synthesis of macroazoinitiator by direct polycondensation for block copolymerization of styrene and butadiene
Authors: Simon Joshy , Bajpai Anjali
Published: October 2004

Macroazoinitiator (MAI) was prepared from hydroxy‐terminated polybutadiene (HTPB) and 4,4′‐azobis‐4‐cyanopentanoic acid (ACPA) by direct polycondensation in the presence of 1‐methyl‐2‐chloropyridinium iodide (MCPI) at room temperature. This MAI proved to be an effective initiator for thermal polymerization of styrene at 60°C. The resulting products were characterized by viscosity measurements and both IR and NMR spectral studies. The ratio of styrene and butadiene units was calculated from NMR spectral data and scanning electron micrography. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2922–2933, 2001
Application of phase dispersion–crosslinking synergism on recycling commingled plastic wastes
Authors: Fang Zhengping , Zeng Minfeng , Cai Guoping , Xu Chengwei
Published: October 2004

A tetra‐component blend, consisting of low‐density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and polystyrene (PS), was studied as a model system of commingled plastic wastes (LDPE/PVC/PP/PS, mass ratio: 70/10/10/10). Effects of chlorinated polyethylene (CPE), ethylene–propylene–diene monomer (EPDM), styrene–butadiene–styrene (SBS), and their mixture (CPE/EPDM/SBS, mass ratio: 2/2/2) on the mechanical properties and morphology of the system were investigated. With addition of several elastomers and their mixture, the tensile strength of the blends decreased slightly, although both the elongation at break and the impact strength increased. Among these elastomers, EPDM exhibited the most significant impact modification effect for the tetra‐component blends. SBS and the mixture have a good phase‐dispersion effect for the tetra‐component blend. By adding a crosslinking agent [dicumyl peroxide (DCP)], the mechanical properties of the tetra‐component blends also increased. When either SBS or the mixture was added to the blend together with DCP, the probability that the crosslinking agent (DCP) would be at the interface improved because of the phase‐dispersion effect of SBS. Therefore, more co‐crosslinked products will form between LDPE and other components. Accordingly, remarkable improvement of the interfacial adhesion and hence the mechanical properties of the tetra‐component blends occurred. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2947–2952, 2001
Novel rapid‐cure adhesives for low temperature using thiirane compound
Authors: Chino Keisuke , Suga Kazuo , Ikawa Masahiro , Satoh Hajime
Published: October 2004

We investigated improvement of workability (viscosity), storage stability, and curing ability of thiirane resin for adhesive applications. The viscosity of bisphenol‐F thiirane resin was lower than that of bisphenol‐A thiirane resin, especially at low temperatures, thus improving ease of handling. Addition of diphenyl decyl phosphite improved its storage stability to a level similar to that of bisphenol‐A epoxy resin. The curing of bisphenol‐F thiirane resin increased three times faster by adding 2,4,6‐tris(dimethylaminomethyl)phenol (DMP‐30) as a tertiary amine. In applications of this new thiirane resin as civil and architectural adhesives, a superior curing ability at low temperature was attained. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2953–2957, 2001
Miscibility of segmented polyurethane/poly(vinyl chloride) blends
Authors: Sudaryanto  , Nishino Takashi , Ueno Masaki , Asaoka Seiji , Nakamae Katsuhiko
Published: October 2004

Miscibilities of segmented polyurethanes (SPUs) and poly(vinyl chloride) (PVC) or functionalized poly(vinyl chloride) (FPVC) were studied with dynamic mechanical analysis, differential scanning calorimetry, and X‐ray diffraction. Mechanical properties of the blends were also studied with tensile measurements. The miscibility of the blends depended greatly on the hard‐segment content of SPU and the existence of the functional groups. The combination of SPU with a low hard‐segment content and PVC with functional groups made the blend system miscible. Moreover, controlling the blend composition of SPU/FPVC allowed us to modify the mechanical properties of SPU, where the elongation at break was multiplied without a significant change in its tensile strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3022–3029, 2001
Swelling behavior of NR/EPDM rubber blends under compression strain
Authors: Botros S. H. , El Sayed A. Mounir
Published: October 2004

The effect of different blend compositions of natural rubber (NR)/ethylene–propylene diene monomer rubber (EPDM) on the swelling behavior of that blend in motor oil under compression strain was investigated. The compression recovery of all blend ratios investigated had positive values at low applied compression values (3%). However, at high compression values (18 and 35%), the compression recovery had negative values. The lower weight uptake of motor oil was shown by the EPDM vulcanizate, whereas the 25/75 NR/EPDM blend showed the highest compression recovery. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3052–3057, 2001
Dimethylammonium dimethyldithiocarbamate‐accelerated sulfur vulcanization. II. Vulcanization of rubbers and model compound 2,3‐dimethyl‐2‐butene
Authors: Shumane M. , Gradwell M. H. S. , Mcgill W. J.
Published: October 2004

Rubber and model compound 2,3‐dimethyl‐2‐butene were vulcanized for various times with dimethylammonium dimethyldithiocarbamate [(dma)dmtc]‐accelerated sulfur formulations in the absence of ZnO. Model compound systems were analyzed by HPLC, and no reaction intermediates containing pendent groups were found. Crosslinked sulfides, characterized by 1H‐NMR, were found to be essentially bis(alkenyl). Residual curatives were extracted from rubber compounds vulcanized for various times and analyzed by HPLC. Compounds, cured to various crosslink densities, were found to crystallize readily in a density column at subambient temperatures. This supports evidence from model compound systems that pendent groups are largely absent from vulcanizates. It is suggested that a reaction mechanism, similar to that applicable to zinc dimethyldithiocarbamate‐accelerated sulfur vulcanization, may be applicable with (dma)dmtc accelerated formulations. Very limited crosslinking occurred on heating compounds under vacuum, and this can be attributed largely to the rapid loss of (dma)dmtc from rubber at elevated temperatures. However, the slower rate of crystallization on cooling of the gels, compared to the rate in press‐cured vulcanizates of similar crosslink density, was interpreted as evidence that some pendent groups did form during heating with (dma)dmtc/sulfur. Crosslinking of such pendent groups may be inhibited by the loss of (dma)dmtc, that, like zinc dimethyldithiocarbamate, may catalyze their crosslinking, and/or to the loss under vacuum of dimethyldithiocarbamic acid that would form thiol pendent groups that would rapidly crosslink with thiuram pendent groups. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3074–3083, 2001
Processing, crystallization, and dynamic mechanical analysis of high molar mass polysiloxane‐modified PP/CaCO3 composites
Authors: Renger C. J. , Burrows S. J. , Shanks R. A.
Published: October 2004

A ternary system polypropylene (PP)/calcium carbonate (CaCO3)/high molar mass polysiloxane has been investigated with respect to its processing, crystallization, and dynamic mechanical properties. The filling level of PP varied from 2.5 vol % to 6.5 vol % CaCO3 and 0.6 vol % to 2.5 vol % polysiloxane, and the mixing was done in a single screw extruder. The polysiloxane molecules had different functionalities added (epoxy and methacrylate reactivity, respectively). However, the functionality did not influence processing, crystallinity, or mechanical properties. It was found that the polysiloxane molecules tended to surround the CaCO3 particles, thus forming a core‐shell structure. This structure was achieved without surface treatment of the filler. The polysiloxane also provided a lubrication effect in the melt and thus enabled an easier processing of the composite. A nucleating effect of the filler could be detected. The mechanical properties were similar to those found in other core‐shell structured samples, where the structure was achieved by surface treatment. It was found that the polysiloxane exhibited a lubricant effect only if it was mixed with PP together with CaCO3. If polysiloxane was added to the PP matrix alone, screw slippage occurred and the polysiloxane molecules agglomerated. The mechanical properties of these composites were similar to those of pure PP. No influence on the matrix crystallisation could be detected in this case. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3091–3098, 2001
Studies of syntheses and adsorption properties of chelating resin from thiourea and formaldehyde
Authors: Ni Caihua , Yi Changhai , Feng Zhiyun
Published: October 2004

Chelating resins are useful substances in industry because of their extraordinary adsorption properties for specific metal ions. In this study, a new type of chelating resin is synthesized simply by reaction between thiourea and formaldehyde. The synthetic conditions and the structure of the product are approached and the adsorbing capacities for 11 metal ions, adsorbing rates, and selectivities investigated. The results of the experiments show that the resin has high adsorbing capacities for Ag(I): 13.1 mmol/g, and for Au(III): 6.95 mmol/g. Adsorbing rates are close to 100% in dilute solution. Isothermal adsorbing study reveals that the adsorption is monomolecular layer adsorption process. It is hopeful for the resin to be used for concentrating and retrieving Ag(I) and Au(III) ions from their dilute solutions in industry. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3127–3132, 2001
Novel high‐Tg, high‐strength poly(aryl ether) containing quadrephenyl unit
Authors: Banerjee Susanta , Maier Gerhard , Salunke Arun , Madhra Mukesh
Published: October 2004

A novel poly(aryl ether) was prepared by nucleophilic displacement of the fluorine atoms of a 2‐perfluoro‐activated bisfluoro monomer with bisphenol A. The polymer exhibited a weight average molar mass of 3.15 × 105 g mol−1 according to gel permeation chromatography. The poly(aryl ether) showed very good thermal stability, with only a 5% weight loss at 493°C according to thermogravimetric analysis under synthetic air, and it had a glass‐transition temperature at 223°C according to differential scanning calorimetry and at 243°C according to dynamic mechanical thermal analysis. The polymer was soluble in a wide range of organic solvents, including CHCl3, tetrahydrofuran, NMP, dimethylformamide (DMF), and toluene, and was insoluble in dimethyl sulfoxide and acetone. Transparent thin films of the polymer, cast from DMF, exhibited a tensile strength of 65 MPa, a modulus of 2.62 GPa, and an elongation at break of 130%. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3149–3156, 2001
Alcohol recovery with pervaporation: Effect of high 2‐butanol concentration
Authors: Shaban Habib I. , Ali Sami H. , Mathew Johnson
Published: October 2004

Poly dimethyl siloxane (PDMS) membrane was used to separate a synthetic mixture consisting of isopropanol, ethanol, 2‐butanol, and n‐butanol using the pervaporation separation technique. These alcohols are found to occur in naphtha reformate as a result of vapor‐phase reaction of the alkenes in the presence of water and a catalyst. In this work the pervaporation separation efficiency of PDMS membrane toward different alcohols was evaluated by estimation of fluxes and separation factors at different temperatures and pressures. The coupling effect resulting from the presence of identical functional groups was investigated. The activation energies for the transport of each of these alcohols through the membrane were also evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3164–3171, 2001
Study on dyeable polypropylene fiber and its properties
Authors: Yu Chengbing , Zhu Meifang , Shong Xingyuan , Chen Yanmo
Published: October 2004

A disperse dyeable polypropylene fiber has been prepared by admixing polystyrene to the polymer prior to extrusion. Polystyrene has been synthesized at suitable molecule weight and narrow mol wt distribution. The dyeability, mechanical properties, shrinkage, degree of crystallinity, and orientation of pure polypropylene or the blend fibers with different amount of polystyrene were investigated. In addition, the structure of the blend containing 4 and 6% polystyrene was also studied to explain the interesting dyeing behavior of the blend fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3172–3176, 2001
Iosipescu shear deformation and fracture in model thermoplastic polyolefins
Authors: Xiang C. , Sue H.‐J.
Published: October 2004

Shear deformation and fracture behaviors in polypropylene (PP)‐based model thermoplastic polyolefins (TPOs) were investigated with the Iosipescu shear test. The shear deformation process was monitored in situ via video camera to obtain experimental shear stress–strain curves of model TPOs. Shear fracture mechanisms were studied with optical microscopy and scanning electron microscopy. Macroscopically, the cracks in neat PP propagated along the maximum shear plane, which indicated that mode‐II shear failure existed in neat PP. Microscopically, it was shown that shear fracture initiated in the form of partial, discontinuous inclined microcracks that later coalesced and formed the final continuous crack. The incorporation of rubber in PP could transform the shear fracture process into a stretching process in the shear damage zone. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3201–3214, 2001
Preparation and characterization of poly(vinyl alcohol)‐based magnetic nanocomposites. 1. Thermal and mechanical properties
Authors: López Daniel , Cendoya Ione , Torres F. , Tejada Javier , Mijangos Carmen
Published: October 2004

CoFe2O4 magnetic nanoparticles were prepared by in situ precipitation and oxidation of Co2+ and Fe2+ within a sulfonated polystyrene resin. The nanometric particles were characterized by X‐ray diffraction. A ferrofluid was prepared from the CoFe2O4 mineralized polymer resin and water. Poly(vinyl alcohol) (PVA)‐based nanocomposite materials were obtained by mixing different amounts of ferrofluid (compositions ranging within 0–51 wt % of mineralized resin) with an aqueous solution of the polymer. The PVA composite materials were characterized by TGA, DSC, and stress–strain testing. The thermal and mechanical properties of PVA change with filler content, exhibiting an initial increase in these properties due to polymer–filler interactions. After a maximum value, at about 15 wt % of mineralized resin, the mechanical properties decrease probably due to particle aggregation which causes phase separation. The results obtained show that the nanoparticles are dispersed in the amorphous regions of the polymer, the crystalline zones remaining unaltered up to compositions as high as 30 wt %. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3215–3222, 2001
Melt spinning of metallocene catalyzed polypropylenes. I. On‐line measurements and their interpretation
Authors: Bond Eric Bryan , Spruiell Joseph E.
Published: October 2004

The melt spinning of metallocene catalyzed isotactic polypropylene resins was investigated. The details are presented for on‐line studies performed on six miPP resins with melt flow rates (MFRs) between 10 and 100 and a Ziegler–Natta catalyzed isotactic polypropylene resin with a MFR of 35 for comparison. The on‐line studies indicated that, as the molecular weight and polydispersity increased, crystallization occurred closer to the spinneret at higher crystallization temperatures and under lower spin line stresses. Further, as the spinning speed increased, crystallization occurred closer to the spinneret at higher crystallization temperatures because of increased stress in the spin line. These observations were interpreted in terms of an increased rate of crystallization caused by increased molecular orientation in the spin line with increasing molecular weight and increasing spinning speed. This “stress‐enhanced” crystallization was further interpreted in terms of an increased rate of crystal nucleation. It was further concluded that the narrower molecular weight distribution of metallocene resins was the primary factor that produced differences in the structure and properties of fibers spun from these resins compared to those of Ziegler–Natta catalyzed resins of similar weight‐average molecular weight or MFR. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3223–3236, 2001
Kinetic study on peroxidation of benzaldehyde by polymer‐immobilized cobalt‐EDTA complex
Authors: Wang Cheng‐Chien , Li Wen‐Sam , Cheng Shih‐Kai , Chen Chuh‐Yean , Chen Chuh‐Yung , Kuo Jen‐Feng
Published: October 2004

Polymer‐immobilized cobalt‐EDTA complex was prepared by grafted copolymerization of methacrylic acid (MAA) and acrylonitrile (AN initiated by redox initiation of EDTA‐2Na (Ethylenediamine tetraacetic acid disodium salt) with ceric ion (Ce2+)). High yield and selectivity for peroxidation of benzaldehyde were obtained when using the polymer‐immobilized cobalt‐EDTA complex as a catalyst. With the concentration of benzaldehyde increasing, the concentration of perbenzoic acid was increased from 0.38M to 0.98M, but yield of perbenzoic acid decreased from 0.76M to 0.65M. With the amount of the polymer support increased, the yield of perbenzoic acid increased from 70% to 82%. The selectivity remained about 82% in the various amounts of the polymer support. The activation energy of peroxidation of benzaldehyde was 43.4 KJ/mole. The expression of the reaction rate was: ri = k[RCHO][polymer support]0.5. A mechanism for peroxidation of benzaldhyde catalysed by polymer‐immobilized cobalt‐EDTA complex was proposed in this investigation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3248–3257, 2001