bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron‐beam irradiation of poly(vinyl chloride)/epoxidized natural rubber blends in presence of trimethylolpropane triacrylate
Authors: Ratnam Chantara Thevy , Nasir M. , Baharin A. , Zaman Khairul 
Published: October 2004

AbstractElectron‐beam initiated crosslinking of poly(vinyl chloride)/epoxidized natural rubber blends, which contained trimethylolpropane triacrylate (TMPTA), was carried out over a range of irradiation doses (20–200 kGy) and concentrations of TMPTA (1–5 phr). The gel content increased with the irradiation dose and the TMPTA level, although the increase was marginal at higher doses and higher TMPTA levels. Blends containing 3–4 phr TMPTA achieved optimum crosslinking, which in effect caused the maximum tensile strength (TS) at a dose of 70 kGy. A further addition of TMPTA caused a decline in the TS above 40 kGy that was due to embrittlement, which is a consequence of excessive crosslinking and the breakdown of the network structure. The possible formation of a more open network as a result of the breakdown of the network structure was further confirmed by the modulus results. Dynamic mechanical analysis (tan δ curve) and scanning electron microscopy studies on samples irradiated at 0 and 200 kGy were undertaken in order to gain further evidence on the irradiation‐induced crosslinking. The plasticizing effect of TMPTA prior to irradiation and the formation of microgels upon irradiation were also discussed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1926–1935, 2001
Immobilization of chymotrypsin with interpolymer complexes of P(TM‐co‐AAm)/PAA
Authors: Wang Hongzuo , Liu Shiyong , Wang Ying 
Published: October 2004

AbstractChymotrypsin was immobilized with interpolymer complexes formed by the cationic polymer poly(allyltrimethyl ammonium chloride‐co‐acrylamide) [P(TM‐co‐AAm)] and poly(acrylic acid) (PAA). The introduction of a small amount of cationic groups led to a much stronger polymer–polymer interaction between P(TM‐co‐AAm) and PAA. The characteristic pH sensitivity of this kind of complex provided the possibilities of controlling the activity of the immobilized enzyme and separating the immobilized enzyme from the batch by changing the pH of the medium. Compared with the free enzyme, the immobilized chymotrypsin had higher thermal stability, acid–base stability, and stability in use. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2013–2018, 2001
Entrap‐immobilization of invertase on composite gel fiber of cellulose acetate and zirconium alkoxide by sol–gel process
Authors: Nakane Koji , Ogihara Takashi , Ogata Nobuo , Kurokawa Youichi 
Published: October 2004

AbstractWe prepared a composite gel fiber by the gel formation of cellulose acetate and zirconium tetra‐n‐butoxide. Gel fiber is stable in common solvents, phosphate solution, and electrolyte solution. Invertase was entrap‐immobilized on the gel fiber. The immobilization was easily performed under the mild conditions. The apparent Michaelis constant (Km) and maximum reaction velocity (Vmax) were estimated from Eadie–Hofstee plot for immobilized invertase. The Km of immobilized invertase was larger than that of native invertase, while the opposite tendency was observed for the Vmax. The activity for the immobilized invertase became higher with increasing fiber diameter. It indicates that the hydrolysis of sucrose occurs in the neighborhood of the fiber surface. The thermal stability of the immobilized invertase was higher than those of its native counterpart. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2084–2088, 2001
Effect of network morphology on adhesive performance in emulsion blends of acrylic pressure sensitive adhesives
Authors: Tobing Singa , Klein Andrew , Sperling L.H. , Petrasko Bob 
Published: October 2004

AbstractHigh‐gel containing latices and gel‐free latex were blended at various weight ratios. The high‐gel containing latices was made of poly(2‐ethyl hexylacrylate‐stat‐acrylic acid) and the gel‐free latex was made of poly(2‐ethyl hexylacrylate‐stat‐acrylic acid‐stat‐isobutoxymethyl acrylamide) using semicontinuous emulsion polymerization. Films were cast at room temperature and dried at 121°C for 10 min. Adhesive performance was evaluated in terms of loop tack, peel, and shear holding power. It was found that interlinking the microgels by the linear polymer due to the isobutoxymethyl acrylamide‐acrylic acid reaction in the film when heated gave synergistic effects in increasing shear. This interlinking could take place only if the molecular weight between crosslinks (Mc) of the microgels was greater than the entanglement molecular weight of the linear polymer (Me), and if the weight average molecular weight of the linear polymer (Mw) was greater than 2 × Me. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2109–2117, 2001
IR spectroscopy study of cyclic anhydride as intermediate for ester crosslinking of cotton cellulose by polycarboxylic acids. V. Comparison of 1,2,4‐butanetricarboxylic acid and 1,2,3‐propanetricarboxylic acid
Authors: Mao Zhiping , Yang Charles Q. 
Published: October 2004

AbstractIn recent years extensive efforts have been made to use multifunctional carboxylic acids as formaldehyde‐free crosslinking agents for cotton to replace the traditional formaldehyde‐based N‐methylol reagents. In our previous research we found that a polycarboxylic acid esterifies cellulose through the formation of a five‐membered cyclic anhydride intermediate by dehydration of two adjacent carboxyl groups. In this research we used Fourier transform IR (FTIR) spectroscopy to study the formation of cyclic anhydride intermediates and crosslinking of cotton by 1,2,4‐butanetricarboxylic acid (BTA) and 1,2,3‐propanetricarboxylic acid (PCA). BTA and PCA form five‐membered cyclic anhydrides in the same temperature range. Both acids form the anhydrides at lower temperatures when a catalyst is present. When an acid molecule is bonded to cotton through an ester linkage, only PCA is able to form a second anhydride intermediate. We found that PCA is a more effective crosslinking agent, and it imparts higher levels of wrinkle resistance to the cotton fabric than BTA. Therefore, the formation of a five‐membered cyclic anhydride by a polycarboxylic acid accelerates the esterification of cotton by the acid. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2142–2150, 2001
Blends of aliphatic polyesters. IV. Morphology, swelling behavior, and surface and bulk properties of blends from hydrophobic poly(L‐lactide) and hydrophilic poly(vinyl alcohol)
Authors: Tsuji Hideto , Muramatsu Hiroki 
Published: October 2004

AbstractBlend films were prepared from hydrophobic poly(L‐lactide) (PLLA) and hydrophilic poly(vinyl alcohol) (PVA) with different PLLA contents [XPLLA (w/w) = PLLA/(PVA + PLLA)] by solution casting and melt quenching. Their morphology, swelling behavior, and surface and bulk properties were investigated. Polarizing optical microscopy, scanning electron microscopy, differential scanning calorimetry, X‐ray diffractometry, and tensile testing revealed that PLLA and PVA were phase separated in these blend films and the PLLA‐rich and PVA‐rich phases both formed a continuous domain in the blend film of XPLLA = 0.5. The water absorption of the blend films was higher for the blend films of low XPLLA values when compared at the same immersion time, and it was larger than expected from those of nonblended PLLA and PVA films. The dynamic contact angles of the blend films were linearly increased with an increase in XPLLA. The tensile strength and Young's modulus of the dry blend films decreased with a rise in XPLLA, but this dependence was reversed because of the large decreases in tensile strength and Young's modulus for the blend films having high XPLLA values after immersion in water. The elongation at break was higher for the wet blend film than for the dry blend film when compared at the same XPLLA and that of the dry and wet blend films decreased with an increase in XPLLA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2151–2160, 2001
Synthesis of poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate by polymer reaction of carbon dioxide and miscibility of its blends with copolymers of methyl methacrylate and ethyl acrylate
Authors: Park Sung‐Young , Lee Hwa‐Soo , Ha Chang‐Sik , Park Dae‐Won 
Published: October 2004

AbstractPolymeric epoxides were converted to corresponding five‐membered cyclic carbonates in an effective manner. Poly(glycidyl methacrylate) (PGMA) was converted to a poly(2‐oxo‐1,3‐dioxolane‐4‐yl) methyl methacrylate (PDOMMA) by the polymer reaction with carbon dioxide using tetraoctylammonium chloride (TOAC) as a catalyst. The miscibility of blends of PGMA or PDOMMA with copolymers of MMA and ethyl acrylate (MMA‐EA) of two different EA compositions (2 and 5 wt %) was investigated by differential scanning calorimetry (DSC). The films of PGMA or PDOMMA and MMA‐EA (2 and 5 wt %) blends were cast from N,N‐dimethylformamide solution. An optical clarity test and DSC analysis showed that PDOMMA blends were miscible over the entire composition range, but PGMA was immiscible with the MMA‐EA copolymers. It was also found that the miscibility of PDOMMA with 2 wt % MMA‐EA copolymer was better than that of DOMMA with 5 wt % MMA‐EA copolymer. The different miscibility behaviors were investigated in terms of Fourier transform IR spectra and interaction parameters based on the binary interaction model. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2161–2169, 2001
Synthesis and characterization of chlorinated paraffin wax‐bound paraphenylenediamine antioxidant and its application in natural rubber
Authors: Sulekha P. B. , Joseph R. , Prathapan S. 
Published: October 2004

Abstractp‐Phenylenediamine was chemically attached to low molecular weight chlorinated paraffin wax. The polymer‐bound p‐phenylenediamine was characterized by vapor‐phase osmometry (VPO), proton magnetic resonance spectroscopy (1H‐NMR), infrared spectroscopy (IR), and thermogravimetric analysis (TGA). The efficiency and permanence of the polymer‐bound p‐phenylenediamine as an antioxidant was compared with a conventional amine‐type antioxidant in natural rubber vulcanizates. The vulcanizates showed improved aging resistance in comparison to vulcanizates containing a conventional antioxidant. The presence of liquid polymer‐bound p‐phenylenediamine also reduces the amount of the plasticizer required for compounding. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2183–2189, 2001
Swelling behavior of protein‐based superabsorbent hydrogels treated with ethanol
Authors: Rathna G. V. N. , Damodaran Srinivasan 
Published: October 2004

AbstractA fish protein‐based superabsorbent hydrogel has been synthesized by modifying 80% of the ϵ‐amino groups of the protein with ethylenediaminetetraacetic dianhydride followed by crosslinking the remaining ϵ‐amino groups with glutaraldehyde. The hydrogel thus prepared was capable of absorbing about 200 g water per g dry gel after centrifuging at 214g. Denaturation of the gel by treatment with absolute ethanol increased the equilibrium water uptake of the gel from 200 to 425 g water per g of dry gel. The saline uptake of the gel also increased from 24 g saline (0.1M NaCl) for the control gel to 35 g saline per g dry gel for the ethanol‐treated gel. Analysis of the structural state of protein chains in the crosslinked swollen gel network using circular dichroism spectroscopy showed that, whereas the protein chains in the control gel were predominantly in β‐turn form, those in the ethanol‐treated sample were mainly in the α‐helical form. In addition to improving the swelling properties, the ethanol treatment offered the following advantages: 1. It dehydrated the gel and thereby eliminated the need for drying the gel. 2. It extracted low molecular weight off‐odor compounds from the protein gel. 3. It could also extract any residual unreacted glutaraldehyde (believed to be carcinogenic) that might be present in the gel. The ethanol used in the process can be easily recovered and recycled in the process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2190–2196, 2001
Study on a series of main‐chain liquid–crystalline ionomers containing sulfonate groups
Authors: Zhi Junge , Zhang Baoyan , Wu Yanying , Feng Zhiliu 
Published: October 2004

AbstractA series of main‐chain liquid–crystalline ionomers containing sulfonate groups pendant on the polymer backbone were synthesized by an interfacial condensation reaction of 4,4′‐dihydroxy‐α,α′‐dimethyl benzalazine, a mesogenic monomer, with brilliant yellow (BY), a sulfonate‐containing monomer, and a 1/9 mixture of terephthaloyl and sebacoyl dichloride. The structures of the polymers were characterized by IR and UV spectroscopies. DSC and thermogravimetric analysis were used to measure the thermal properties of those polymers, and the mesogenic properties were characterized by a polarized optical microscope, DSC, and wide‐angle X‐ray diffraction. The ionomers were thermally stable to about 310 °C. They were thermotropic liquid–crystalline polymers (LCPs) with high mesomorphic‐phase transition temperatures and exhibited broad nematic mesogenic regions of 160–170 °C, and they were lyotropic LCPs with willowy leaf‐shaped textures in sulfuric acid. However, the thermotropic liquid–crystalline properties were somewhat weakened because the concentration of BY was more than 8%. The inherent viscosity in N‐methyl‐2‐pyrrolidone suggested that intramolecular associations of sulfonate groups occurred at low concentration, and intermolecular associations predominated at higher concentration. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2210–2218, 2001
A copper‐based reverse ATRP process for the living radical polymerization of methyl methacrylate
Authors: Qin Dong‐Qi , Qin Shu‐Hui , Qiu Kun‐Yuan 
Published: October 2004

AbstractThe reverse atom transfer radical polymerization (RATRP) technique using CuCl2/bipyridine (bipy) complex as a catalyst was applied to the living radical polymerization of methyl methacrylate (MMA). A hexa‐substituted ethane thermal iniferter, diethyl 2,3‐dicyano‐2,3‐diphenylsuccinate (DCDPS), was used as the initiator in this copper‐based reverse ATRP initiation system. The reversible dissociation nature of DCDPS gives a more suitable amount of primary radical than formerly used conventional initiators, such as AIBN. High molecular weight and narrow molecular weight distribution (Mw/Mn ≈ 1.20) of the resulting PMMA was obtained in bulk and in solution polymerization at 85°C. End‐group analysis result by 1H‐NMR spectroscopy shows that the polymer obtained is ω‐functionalized by a chlorine group, which can be used as macroinitiator for chain extension and block copolymerization with a conventional ATRP catalyst. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2237–2245, 2001
Synthesis and characterization of poly(1,4‐dihydroxyanthraquinone terephthalate)
Authors: Meng Qinghua , Huang Deyin , Xiang Liang , Wei Shaohua 
Published: October 2004

AbstractA novel polymeric dye containing an anthraquinone ring was prepared by solution polycondensation. The molecule geometry was fully optimized on the basis of the AM1 method. The hydrogen bond was formed and retained coplanarity in the molecular structure. In its UV spectrum, a large hypsochromic shift and a hypochromic effect were observed due to polyesterification. The polymeric dye was also characterized by means of IR and TG. Its thermal degradation mechanism was elucidated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2246–2248, 2001
Processing of gel‐spun poly(β‐hydroxybutyrate) fibers
Authors: Gordeyev S. A. , Nekrasov Yu. P. , Shilton S. J. 
Published: October 2004

AbstractPoly(β‐hydroxybutyrate) (PHB) is a bacteria storage biodegradable polyester that is considered to be a natural substitute for synthetic thermoplastics in many applications. However, brittleness hampers its utility. This study shows that oriented elastic fibers of PHB with favorable mechanical properties (360‐MPa tensile strength and 5.6‐GPa Young's modulus) can be produced by the spinning and drawing of a concentrated PHB gel using a three‐stage fiber processing technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2260–2264, 2001
Mechanism analysis of the PEG‐participated Gilch synthesis for soluble poly(p‐phenylene vinylene) derivatives
Authors: Yin Chun , Yang Chang‐Zheng 
Published: October 2004

AbstractBy introducing poly(ethylene glycol) (PEG) into the Gilch reaction system for the synthesis of soluble poly(p‐phenylene vinylene)s (PPVs), significant changes were observed. First, with the involvement of PEG, the polymerization degree increases significantly and the molecular weight distribution becomes wider. The multimodial characteristic of the GPC curves at low conversions is quite evident. Second, at low PEG content, gelation dramatically disappears; with an increase of PEG, gelation reappears. From the above experimental results, the existence of various types of polymerization‐active species and the anionic polymerization mechanism are confirmed, which are due to the dissociation of the carbanion–cation pairs by the complexing effect of PEG. At the same time, the enhanced dissociation of the base (t‐BuO−K+) ion pairs by PEG may be responsible for the dramatic disappearance of gelation. Free t‐BuO− anions have strengthened the basicity and accelerated the conjugation‐formation process which competes with the interchain by‐reactions. Gelation is therefore avoided. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 263–268, 2001
Control of molecular weight in tetrahydrofuran polymerization initiated by heteropolyacid
Authors: Chen Yu , Zhang Guangli , Zhang Hongzhi 
Published: October 2004

AbstractBoth anhydrous and hydrated heteropolyacid can be used to initiate the tetrahydrofuran polymerization in the presence of ethylene oxide promoter, in regard to the crystallization water of the hydrated one as a part of the extra‐added water for controlling the molecular weight. The polyether glycol having number‐average molecular weight of 2000 ± 100 or 1000 ± 50 was prepared in yield beyond 50% by the process without neutralization or neutralization and washing with water after polymerization, respectively. A modified equation based upon conversion of polymerization and concentrations of molecular weight controller and heteropolyacid with a correction factor for predicting the number‐average molecular weight of the product was given. The products were characterized by nuclear magnetic resonance, gel permeation chromatography, and differential scanning calorimetry analyses. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 269–275, 2001
Physical and chemical effects of diethyl N,N′‐diethanolaminomethylphosphate on flame retardancy of rigid polyurethane foam
Authors: Wang Xiu‐Li , Yang Ke‐Ke , Wang Yu‐Zhong 
Published: October 2004

AbstractDiethyl N,N‐diethanolaminomethylphosphate could react with isocyanate because it contained hydroxy group. This was confirmed by FTIR spectrum. It did not produce any effect on the foam structure of rigid polyurethane foam (RPUF). SEM, IR spectrum, and thermal analysis were used for investigation of the physical and chemical changes during the combustion of flame‐retardant RPUF. It was shown that the flame retardancy changed the thermal decomposition behavior of RPUF, widened the decomposition temperature region of RPUF, reduced the amounts of decomposition products at high temperatures, and increased the decomposition residuals arisen from charring of flame‐retardant RPUF. Those changes improved the flame retardancy of RPUF. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 276–282, 2001
Ethoxylated nonyl phenols and ethoxylated fatty alcohols–ceric ion redox systems for aqueous polymerization of vinyl monomers
Authors: Öz Nesri̇n , Akar Ahmet , Yilmaz Nurten 
Published: October 2004

AbstractEthoxylated nonyl phenols, ethoxylated fatty alcohols, and ceric ammonium nitrate redox systems were used for the polymerization of vinyl and acrylic monomers such as acrylonitrile, styrene, and acrylic acid. The initiating radical was formed on reducing organic compound which in turn initiated polymerization to give polymers containing chain ends of ethoxylated nonyl phenols and ethoxylated fatty alcohols that showed much higher water absorption. The effects of the concentration of Ce+4 salt, ethoxylated nonyl phenols, and monomers on both the yield and the molecular weight of corresponding polymers were studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 310–313, 2001
Characterization of retanned chrome bovine leather by thermomechanical analysis
Authors: Bosch T. , Manich A. M. , Carilla J. , Palop R. , Cot J. 
Published: October 2004

AbstractThe thermomechanical analysis is applied to characterize the shrinking process of bovine chrome leather. The interpretation of the curves obtained is performed and a value of glass transition temperature is estimated. The influence of the sampling zone on the thermomechanical parameters is discussed. The influence of different “retanning agents,” which act as crosslinking compounds on the fibrous structure of collagen, is also evaluated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 314–322, 2001
Flame‐retarding materials. II. Synthesis and flame‐retarding properties of phosphorus‐on‐pendent and phosphorus‐on‐skeleton polyols and the corresponding polyurethanes
Authors: Wang Tzong‐Liu , Cho Yu‐Liang , Kuo Ping‐Lin 
Published: October 2004

AbstractA phosphorus‐on‐skeleton compound was synthesized by reacting phenyl dichlorophosphate (PDCP) with 2‐hydroxyethyl methacrylate (HEMA). This monomer was then copolymerized with other acrylic monomers to form a hydroxy‐containing copolymer, which was then used as the polyol in the synthesis of a polyurethane. Phosphorus‐on‐pendent copolymers and phosphorus‐free copolymers and their corresponding polyurethanes were also prepared for comparison with the phosphorus‐on‐skeleton material in terms of their flame‐retardant properties. The flame retardancy and degradation mechanism of these copolymers and polyurethanes were analyzed with thermogravimetric analysis (TGA) and infrared spectroscopy. Although those phosphorus‐on‐skeleton copolymer polyols have less flame‐retarding ability than that of the phosphorus‐on‐pendent copolymer polyol because of less phosphorus content, it was evident that the phosphorus‐on‐skeleton polyurethanes were more effective flame retardants than the phosphorus‐on‐pendent polyurethanes. This was attributed to the fact that the crosslinking arising from the phosphorus‐on‐skeleton copolymer polyols has a tremendous effect on the flame‐retarding ability of the corresponding polyurethanes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 343–357, 2001