bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and biodegradation of starch‐graft‐poly(hexylene adipate)
Authors: Zhu Changying , Kou Xiaodi , You Yingcai , Zhang Zhiqiang , Zuo Ju 
Published: May 2003

AbstractPoly(hexylene adipate) (PHA) was synthesized by the direct condensation of hexandiol and adipic acid with p‐toluene sulfonic acid as a catalyst, dimethyl benzene as a solvent. The terminal carboxyl group of the polyester was then converted to acyl chloride by a solution of SOCl2 in toluene. The degree of acylation (DA) was very much dependent on the molecular weight and the type of the other terminal group of the PHA (hydroxyl or capped with an ester group). A high concentration of SOCl2 increased DA, but the scission of the polyester chain was observed. The graft reaction of the acylated PHA with starch was carried out in dried dimethyl sulfoxide. The results show that the percentage grafting (G) and graft efficiency were determined by several factors, including the weight ratio of the reactants, reaction temperature, and molecular weight of PHA. Biodegradation tests in both the laboratory and the natural environment indicated that the degradation rate of starch‐g‐PHA was much faster than that of PHA. For example, the weight loss of PHA was 1.3% after 36 days of natural soil burial, whereas the weight loss of starch‐g‐PHA (G = 39.1%) reached 28% after the same time period. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 848–854, 2003
Formation of microcapsules of medicines by the rapid expansion of a supercritical solution with a nonsolvent
Authors: Matsuyama Kiyoshi , Mishima Kenji , Hayashi Ken‐Ichiro , Ishikawa Hideharu , Matsuyama Hideto , Harada Toru 
Published: May 2003

AbstractThe rapid expansion from a supercritical solution with a nonsolvent (RESS‐N) was applied to the formation of polymeric microcapsules containing medicines such as p‐acetamidophenol, acetylsalicylic acid, 1,3‐dimethylxanthine, flavone, and 3‐hydroxyflavone. A suspension of medicine in carbon dioxide (CO2) containing a cosolvent and dissolved polymer was sprayed through a nozzle to atmospheric pressure. The pre‐expansion pressure was 10–25 MPa, and the temperature was 308–333 K. The polymers were poly(L‐lactic acid) (molecular weight = 5000), poly(ethylene glycol) (PEG; PEG4000, molecular weight = 3000; PEG6000, molecular weight = 7500; and PEG20000, molecular weight = 20,000), poly(methyl methacrylate) (molecular weight = 15,000), ethyl cellulose (molecular weight = 5000), and PEG–poly(propylene glycol)–PEG triblock copolymer (molecular weight = 13,000). The solubilities of the polymers as coating materials and these medicines as core substance were very low in CO2. However, the solubilities of these polymers in CO2 significantly increased with the addition of low molecular weight alcohols as cosolvents. After RESS‐N, polymeric microcapsules were formed according to the precipitation of the polymer caused by a decrease in the solvent power of CO2. This method offered three advantages: (1) enough of the coating polymers, which were insoluble in pure CO2, dissolved; (2) the microparticles of the medicine were encapsulated without adhesion between the particles because a nonsolvent was used as a cosolvent and the cosolvent remaining in the mixture was removed by the gasification of CO2; and (3) the polymer‐coating thickness was controlled with changes in the feed composition of the polymer for drug delivery. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 742–752, 2003
Examination of the role of oxygen in the photografting of methacrylic acid on a polyethylene film with a mixed solvent consisting of water and organic solvents
Authors: Irwan Ginting Suka , Kuroda Shin‐Ichi , Kubota Hitoshi , Kondo Takashi 
Published: May 2003

AbstractThe photografting of methacrylic acid (MAA) on a linear low‐density polyethylene film (thickness = 30 μm) under air and nitrogen atmospheres was investigated at 60°C in mixed solvents consisting of water and an organic solvent, with xanthone as a photoinitiator. The organic solvents used were acetone, methanol, tetrahydrofuran, and dioxane. A maximum percentage of grafting occurred at a certain concentration of the organic solvent in the mixed solvent. This was observed for the systems under both air and nitrogen. The grafting reaction under air exhibited an induction period, but the rate of grafting after the period was greater than that under nitrogen. The formation of poly(ethylene peroxide)s by photoirradiation seemed to be a factor for the accelerated photografting under air. On the basis of attenuated total reflection infrared spectroscopy and scanning electron microscopy of the grafted film, the MAA‐grafted chains of the sample prepared under air tended to penetrate more deeply inside the film than those of the sample prepared under nitrogen. The resulting grafted films exhibited a pH‐responsive character: the grafted films shrank in an acidic medium but swelled in alkaline medium. This was evaluated from measurements of dimensional changes in the grafted films. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 992–998, 2003
Morphological characterization of the core–shell latex particle by transmission electron microscopy and image analysis
Authors: Li Zhengmin , Yang Jinghe , Yu Yuanzhang , Xu Xingzhong , Meng Xiantan , Yu Weijun , Xu Xiuling , Li Lei , Yue Xiuying 
Published: May 2003

AbstractTo describe the morphology of the core–shell latex particle of methyl methacrylate–butadiene–styrene graft copolymer (MBS) quantitatively, we propose four parameters, that is, the diameter of the core, the shell thickness (TH), the roundness of the core, and the eccentricity (E); we calculated these parameters with geometrical parameters determined by the analysis of transmission electron microscope images. The mean values and distributions of the four parameters based on a certain amount of particles were used for quantitative characterization of MBS latex samples. With increasing monomer‐to‐polymer ratios of the graft polymerization, both the MBS TH and the numbers of homopolymer particles increased, and the core–shell morphology tended to be irregular. For the MBS latices derived from poly(styrene–butadiene) latex with a wide distribution of particle sizes, the core–shell structures of the larger particles were different from those of smaller ones to a certain extent, and both the TH and the E decreased with increasing core size. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 855–861, 2003
Thermosensitive poly(n‐isopropylacrylamide) hydrogels bonded on cellulose supports
Authors: Xie Jiangbing , Hsieh You‐Lo 
Published: May 2003

AbstractA two‐step initiation and polymerization process was developed for the preparation of two series of hydrogel–cellulose composites with distinctively different morphologies and swelling behaviors. Hydroentangled cotton cellulose fibers were optimally initiated in 20 mM aqueous ammonium cerium(IV) nitrate for 15 min and then polymerized in aqueous solutions of N‐isopropylacrylamide (NIPAAm) monomer and N,N′‐methylene bisacrylamide (BisA) crosslinker. The extents of hydrogels on the cellulose solids could be controlled by variations in the concentrations of the monomer and crosslinker as well as the NIPAAm/BisA solution‐to‐solid ratios. The two series of hydrogel–cellulose composites formed were hydrogel‐covered/filled cellulose (I) and cellulose‐reinforced hydrogel (II) composites. Series I composites were synthesized with NIPAAm/BisA solutions below the liquid saturation level of the cellulose; this led to pore structures (size and porosity) that depended on both the extent and swelling of the grafted hydrogels. Series II composites were polymerized in the presence of excessive NIPAAm/BisA solutions to produce cellulose solids completely encapsulated in the hydrogels. All the cellulose‐supported hydrogels exhibited lower extents of phase transition over a wider temperature range (28–40°C) than the free poly(N‐isopropylacrylamide) hydrogels (32°C). These findings demonstrate that hydrogels can be used to control the pore structure of cellulose and can be supported with cellulose fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 999–1006, 2003
Enhancement of the chemical resistance of nitrile rubber by direct fluorination
Authors: Vega‐Cantú Yadira , Hauge Robert , Norman Lewis , Billups W. E. 
Published: May 2003

AbstractNitrile rubber (NBR), poly(acrylonitrile‐co‐butadiene) or NBR packers, are used to seal oil‐well tubing, where they often come into contact with ZnBr2 brines at high temperatures and pressures. Under these conditions, NBR exhibits accelerated chemical degradation, which results in embrittlement and cracking. Although alternative fluoropolymers exhibit excellent chemical resistance, their strength is less than NBR, and replacement of the usual gasket materials with fluoroelastomers is expensive. We have demonstrated that a fluoropolymer surface on a nitrile elastomer provides the necessary chemical resistance while the elastomer retains strength. This can be achieved by direct fluorination, a rather easy and inexpensive process. Samples of NBR O‐rings were fluorinated by exposure to F2 and F2/HF mixtures at various temperatures. Although fluorination by F2 produced the desired fluoropolymer layer, fluorination by F2/HF (hydrofluoric acid) mixtures gave a smoother fluorinated layer at lower temperatures and shorter reaction times. Elemental analysis showed that the fluorinated layer eliminated ZnBr2 diffusion into the NBR polymeric matrix. Surface fluorination also significantly retarded the loss of the mechanical properties of NBR when it was exposed to zinc bromide fluid. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 971–979, 2003
Polystyrene/polybutadiene blends: An analysis of the phase‐inversion region and cophase continuity and a comparison with theoretical predictions
Authors: Joseph Susan , Rutkowska Maria , Jastrzêbska Mariola , Janik Helena , Haponiuk Jozef T. , Thomas Sabu 
Published: May 2003

AbstractBlends of polystyrene and polybutadiene were prepared by melt mixing. The melt rheology behavior of the blends was studied with a capillary rheometer. The morphology of the blends was examined with scanning electron microscopy. The levels of continuity and cocontinuity were studied by both morphology and dissolution techniques. The region of phase inversion was observed at 50 wt % polystyrene. Various theoretical models were applied to determine the region of cophase continuity and to locate the point of phase inversion. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1007–1016, 2003
Synthesis and characterization of polystyrene/poly(4‐vinylpyridine) triblock copolymers by reversible addition–fragmentation chain transfer polymerization and their self‐assembled aggregates in water
Authors: Yuan Jian‐Jun , Ma Rui , Gao Qing , Wang Yi‐Feng , Cheng Shi‐Yuan , Feng Lin‐Xian , Fan Zhi‐Qiang , Jiang Lei 
Published: May 2003

AbstractReversible addition–fragmentation chain transfer polymerization (RAFT) was developed for the controlled preparation of polystyrene (PS)/poly(4‐vinylpyridine) (P4VP) triblock copolymers. First, PS and P4VP homopolymers were prepared using dibenzyl trithiocarbonate as the chain transfer agent (CTA). Then, PS‐b‐P4VP‐b‐PS and P4VP‐b‐PS‐b‐P4VP triblock copolymers were synthesized using as macro‐CTA the obtained homopolymers PS and P4VP, respectively. The synthesized polymers had relatively narrower molecular weight distributions (Mw/Mn < 1.25), and the polymerization was controlled/living. Furthermore, the polymerization rate appeared to be lower when styrene was polymerized using P4VP as the macro‐CTA, compared with polymerizing 4‐vinylpyridine using PS as the macro‐CTA. This was attributed to the different transfer constants of the P4VP and PS macro‐CTAs to the styrene and the 4‐vinylpyridine, respectively. The aggregates of the triblock copolymers with different compositions and chain architectures in water also were investigated, and the results are presented. Reducing the P4VP block length and keeping the PS block constant favored the formation of rod aggregates. Moreover, the chain architecture in which the P4VP block was in the middle of the copolymer chain was rather favorable to the rod assembly because of the entropic penalty associated with the looping of the middle‐block P4VP to form the aggregate corona and tailing of the end‐block PS into the core of the aggregates. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1017–1025, 2003
Treatment of cellulose with cationic, nucleophilic polymers to enable reactive dyeing at neutral pH without electrolyte addition
Authors: Blackburn Richard S. , Burkinshaw Stephen M. 
Published: May 2003

AbstractReactive dyeing of cotton requires very high concentrations of salt, which pollutes freshwater courses. The dyeing effluent is highly colored as a result of high levels of hydrolysis of the dye, and high volumes of water are used in the wash‐off process to remove the hydrolyzed dye in order to achieve the excellent wash‐fastness levels expected. A substantive cationic, nucleophilic polymer was applied to cotton as a pretreatment agent prior to dyeing. This enabled salt and alkali to be completely eliminated from the dyeing process, significantly reducing the duration of the dyeing process and requiring less than 50% of the volume of water compared with those of the standard reactive dyeing processes. Dyeings secured using the pretreatment method required one simple washing stage to give wash‐fastness values equal to those observed for the standard reactive dyeings that required several wash‐off stages. The color strength of the pretreated dyeing was also slightly higher than that of the standard dyeings, and this was attributable to a reduction in dye hydrolysis and hence a higher fixation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1026–1031, 2003
Melt blending of poly(ethylene terephthalate) with polypropylene in the presence of silane coupling agent
Authors: Oyman Z. O. , Tinçer T. 
Published: May 2003

AbstractA silane coupling agent (SCA) was used as a compatibilizer for polypropylene–poly(ethylene teraphthalate) (PP–PET) blends with 20, 40, 50, and 60% PET compositions by weight. PP–PET mixtures were blended with and without an SCA by a single‐screw extruder. The effect of silane modification on the tensile and impact properties of the blends was investigated. The morphology and thermal behavior of the blends were examined with scanning electron microscopy (SEM) and differential scanning calorimetry (DSC), respectively. The presence of the SCA used in this work extensively improved the mechanical properties of the blends. Mechanical properties were found to be highly dependent on the numbers of extrusions. SEM studies showed that substantially different morphology with better adhesion existed when SCA‐treated blends were compared to nontreated PP–PET blends. The presence of individual melting temperatures of the polymers in all compositions with no significant Tm depression indicated that PET and PP were crystallized separately. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1039–1048, 2003
Chemical interaction in blends of polyamide and butyl rubbers
Authors: Van Dyke J. D. (Jack) , Gnatowski Marek , Koutsandreas Andy , Burczyk Andrew , Duncan Scott 
Published: May 2003

AbstractThis study focuses on the interaction between polyamide and butyl or bromobutyl rubbers blended in a high shear environment. The fact that these two normally incompatible systems can be mixed is explained by a chemical reaction that occurs between polyamide and the butyl rubber components during processing. Measurement of the melt viscosity and differential scanning calorimetry of these blends, along with analysis of the extracted soluble butyl rubber component, supports the presence of small quantities of block or graft polymers in the system, significant crosslinking during the blending process, and possibly other interactions between the blend components. The effect of electron beam radiation on interaction in these blends was briefly evaluated and was found to increase crosslinking in the blends, with some degradation of the polyamide component. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 980–991, 2003
Synthesis and characterization of ZnO nanostructures templated using diblock copolymers
Authors: Mulligan Robert F. , Iliadis Agis A. , Kofinas Peter 
Published: May 2003

AbstractThe development of self‐assembled ZnO nanoparticles within a diblock copolymer matrix using wet chemical processing specific to ZnO is reported. Diblock copolymers consisting of polynorbornene and poly(norbornene–dicarboxcylic acid) (NOR/NORCOOH) were synthesized with a block repeat unit ratio of 400 for the first block and 50 for the second block, to obtain spherical microphase separation. The block copolymer self‐assembly was used to template the growth of ZnO nanoparticles by introducing a ZnCl2 precursor into the second polymer (NORCOOH) block at room temperature and processing the copolymer by wet chemical methods to substitute the chlorine atoms with oxygen. X‐ray photoemission spectroscopy (XPS) verified the conversion of ZnCl2 to ZnO by monitoring the disappearance of the Cl 1s peak and the shift in the binding energy of the Zn 2p3 peak in the high‐resolution spectra. The substitution of Cl by O was found to be a highly preferential process, whereby only one approach using a weak base (NH4OH) succeeded in effectively replacing Cl with O to result in spherical ZnO nanoparticles having a size ranging from 7 to 15 nm, as determined by transmission electron microscopy. The development of such block copolymer‐templated ZnO nanoparticles% is important in enabling the functionalization of large‐area nanodevice technologies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1058–1061, 2003
Humidity‐sensitive properties of new polyelectrolytes based on the copolymers containing phosphonium salt and phosphine function
Authors: Lee Chil‐Won , Kim Ohyoung , Gong Myoung‐Seon 
Published: May 2003

AbstractA simple strategy was developed based on a new reactive function‐ and a salt‐containing new monomer, 4‐vinylbenzyl dimethyl 2‐(dimethylphosphino)ethyl phosphonium chloride (VDEPC), to obtain stable humidity‐sensitive membranes. The major ingredient of a humid membrane is crosslinked polyelectrolytes obtained from copolymers of VDEPC/2‐ethylhexyl acrylate (2‐EHA) = 1/0, 4/1, and 2/1. Isothermal humidity absorption experiments were performed for the estimation of humidity‐sensing materials. The crosslinked copolymers prepared from the reaction of VDEPC/2‐EHA = 4/1 with 1,4‐dichlorobutane showed an average impedance of 595, 39.1, and 3.9 KΩ at 30, 60, and 90% RH, respectively. Their hysteresis, temperature dependence, frequency dependence, and response time were measured. The reliability including water resistance and a long‐term stability were estimated for the application of the common humidity sensor. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1062–1070, 2003
Ultrafine fibers electrospun from biodegradable polymers
Authors: Zeng Jing , Chen Xuesi , Xu Xiaoyi , Liang Qizhi , Bian Xinchao , Yang Lixin , Jing Xiabin 
Published: May 2003

AbstractBiodegradable poly(l‐lactide) (PLLA) and poly(ε‐caprolactone) (PCL) were electrospun into ultrafine fibers. The technological parameters influencing the spinning process and morphology of the fibers obtained were examined. These parameters included solvent composition, addition of certain organic salts, molecular weight and concentration of the polymers, capillary diameter, air ventilation, and pressure imposed on the surface of the solution as well as electrostatic field. By properly choosing and adjusting these parameters, submicron PLLA and PCL fibers with a narrow diameter distribution were prepared. Scanning electronic microscopy was used to observe the morphology and diameter size of the fibers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1085–1092, 2003
Separation of superoxide dismutase by size‐exclusion chromatography column packed with regenerated cellulose gels
Authors: Yang Guang , Xiong Xiaopeng , Zhang Lina 
Published: May 2003

AbstractA preparative size‐exclusion chromatography (SEC) column (500 × 10 mm) packed with regenerated cellulose gel particles was used for the separation of superoxide dismutase (SOD) from pig blood. The fraction F‐5, with an Mw of 12.4 × 104, composed of more aspartic acid (Asp), glutamine (Glu), and tyrosine (Tyr) but less cysteine (Cys), has the highest specific activity (204 units per mg protein), which was higher than that of the commercial product (175 units per mg protein). The change of fluorescence intensities at zero concentration of the fractions was identical to that of the activities. The results from amino acid sequence analysis and size‐exclusion chromatography combined with static laser light scattering (SEC–LLS) analysis indicated that the separation mechanism of SOD is based on both size exclusion and ion affinity. They also showed that the activity of SOD is determined mainly by its composition. At a flow rate of 0.62 mL min−1, 42 mg of a high specific activity product can be obtained from crude SOD in 1 day. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 763–768, 2003
Use of binary ethanol/water model solutions to mimic the interaction between a plastic material and pharmaceutical formulations
Authors: Jenke Dennis R. , Brennan Jill , Doty Mark , Poss Mitchell 
Published: May 2003

AbstractThe interaction of model compounds with a polyolefin plastic material was examined in binary mixtures of ethanol/water to assess the impact of the solvent polarity on the magnitude of the interaction. The interactions investigated included both compound sorption from the solution by the plastic material and leaching of plastic components into the solution. The magnitude of the interaction at equilibrium, expressed as an equilibrium interaction constant, could be linearly related to the compound's octanol–water partition coefficient (Po/w) and the solvent's polarity (Pm). The utility of the resulting mathematical interaction model was assessed by examining the compatibility of the sample plastic system with a simulated pharmaceutical product vehicle containing a typically encountered surfactant. The nature of the plastic–solution interaction in the surfactant was unlike that observed in the binary model systems, consistent with the expectation that a surfactant's behavior is mediated by mechanisms other than simple polarity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1049–1057, 2003
Effect of carbon black on the mechanical and dielectric properties of rubber ferrite composites containing barium ferrite
Authors: Soloman M. A. , Kurian Philip , Anantharaman M. R. , Joy P. A. 
Published: May 2003

AbstractFine particles of barium ferrite (BaFe12O19) were synthesized by the conventional ceramic technique. These materials were then characterized by the X‐ray diffraction method and incorporated in the natural rubber matrix according to a specific receipe for various loadings of ferrite. The rubber ferrite composites (RFC) thus obtained have several applications, and have the advantage of molding into complex shapes. For applications such as microwave absorbers, these composites should have an appropriate dielectric strength with the required mechanical and magnetic properties. The N330 (HAF) carbon black has been added to these RFCs for various loadings to modify the dielectric and mechanical properties. In this article we report the effect of carbon black on the mechanical and dielectric properties of these RFCs. Both the mechanical and dielectric properties can be enhanced by the addition of an appropriate amount of carbon black. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 769–778, 2003