bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress‐induced crystallization of biaxially oriented polypropylene
Authors: Yang Wei , Li Zhong‐Ming , Xie Bang‐Hu , Feng Jian‐Min , Shi Wei , Yang Ming‐Bo
Published: May 2003

The hot stretching of thick, extruded sheets at high temperatures is a very important process in the production of finished biaxially oriented polypropylene (BOPP) films with special inner structures. Through a simulation of hot stretching in the machine direction (MD) of the processing of BOPP films, it was found that at high temperatures, the stretching ratio greatly influenced the obtained crystalline structure, as observed by differential scanning calorimetry (DSC). Also, in MD hot stretching, the crystallinity increased by an average of 20%. Wide‐angle X‐ray diffraction patterns of extruded sheet samples with and without stretching confirmed the structural changes shown by DSC, and the results proved that β‐crystal modification did not occur during the MD hot‐stretching process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 686–690, 2003
Synthesis and properties of novel aromatic polyamides derived from 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy) phenyl]hexafluoropropane and aromatic dicarboxylic acids
Authors: Gutch Pranav K. , Banerjee Susanta , Jaiswal Devendra K.
Published: May 2003

A series of polyamides were synthesized by the direct polycondensation of 2,2‐bis[4‐(4‐amino‐2‐fluorophenoxy)phenyl]hexafluoropropane with various commercially available dicarboxylic acids such as terephthalic acid, isophthalic acid, 5‐t‐butyl isophthalic acid, and 2,6‐naphthalene dicarboxylic acid. The synthesized polyamides were soluble in several organic solvents such as N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, and chloroform, and they exhibited inherent viscosities of 0.42–0.59 dL/g. The polyamides exhibited weight‐average molecular weights of up to 26,000, which depended on the exact repeating unit structure. These polyamides showed good thermal stability up to 440°C for a 10% weight loss in synthetic air. The polyamides synthesized from 5‐t‐butyl isophthalic acid and isophthalic acid exhibited glass‐transition temperatures of 217 and 185°C, respectively (by differential scanning calorimetry) in nitrogen. The polyamides synthesized from terephthalic acid and 2,6‐naphthalene dicarboxylic acid showed melting temperatures of 319 and 385°C, respectively. The polyamides films were pale yellow, with tensile strengths of up to 82 MPa, moduli of elasticity of up to 2.3 GPa, and elongations at break of up to 9%, which depended on the exact repeating unit structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 691–696, 2003
Preparation of liquid crystalline networks doped with azobenzene molecules and their photochemical grating formation behavior
Authors: Kurihara Seiji , Yoneyama Daisuke , Ogata Tomonari , Nonaka Takamasa
Published: May 2003

Liquid crystalline (LC) networks with macroscopically uniaxial molecular orientation were prepared by photopolymerization of mixtures of LC mono‐ and diacrylates and a donor–acceptor azobenzene compound in a homogeneous glass cell at the nematic phase, and their photoresponsive properties were investigated. The transparency of the LC networks decreased with a decrease in the crosslinking density with LC diacrylate. The LC networks crosslinked with a few mol percent of LC diacrylate showed an enantiotropic phase transition from an anisotropic phase to an isotropic phase as well as high transparency. Formation and removal of the grating were investigated by irradiating two writing beams with an argon ion laser. Grating less than 1.0 μm could be achieved, and the response time of formation and removal of the grating were in a range of a few tens of microseconds. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 943–951, 2003
Adhesion mechanisms of enamel–varnishes on copper: Adhesion promoter versus corrosion inhibitor
Authors: Boullanger C. , Chapel J. P. , Danel L. , Fournier J.
Published: May 2003

The role of adhesion promoters, copper oxidation, and thermal aging in the adhesion mechanism of enamel on copper winding wires is investigated. Evidence is presented on the predominant role of the copper oxide at the interface in the wire–enamel adhesion phenomena. The oxidation process and the copper oxides stability at the interface are seen to strongly depend upon the thermal aging of the wire and the nature of both the enamel and the promoter. Atomic force and scanning electron microscopy analyses show that so‐called promoters act more efficiently as corrosion inhibitors than as adhesion enhancers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 952–958, 2003
Study on mechanical properties and intermolecular interaction of silicone rubber/polyurethane/epoxy blends
Authors: Chiu Hsien‐Tang , Chiu Shih‐Hsuan , Wu Jyh‐Horng
Published: May 2003

The aggregation structure and mechanical properties of liquid silicone rubber, polyurethane (PU), and epoxy (EP) blends were studied. The molecular structure was evaluated by FTIR, and the intermolecular interaction of the three‐phase polyblends was measured by dynamic mechanical analysis. The mechanical properties, including the tension, compression, shear, and tear performance, were measured by a material testing system. From the relationship between the intermolecular interaction and mechanical properties, we found that the aggregation structure of the three‐phase blends was influenced by the reaction between silicone and PU, silicone and EP, and PU and EP, which resulted in a change of the crosslinking density and an interpenetrating polymer network structure. Thus, the dominant three‐phase mechanical properties are closely related to the aggregation structure. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 959–970, 2003
Preparation of large‐sized graded‐index polymer preform
Authors: Ding Wen , Xu Chuanxiang , Xu Sihua , Wang Shoutai
Published: May 2003

In this article, an improved method was put forward to overcome the defect of interfacial‐gel polymerization technique. The cause of the defects was analyzed, and the factors of reaction conditions on formation of the graded‐index (GI) polymer preform (i.e., reaction temperature and atmosphere pressure) were investigated. High‐performance large‐sized GI polymer preform was prepared by this improved technique, in which diphenyl sulfide was used as higher refractive index molecules. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 817–820, 2003
A lattice‐fluid, group‐contribution treatment of the glass transition of homopolymers, copolymers, and polymer solutions
Authors: Hamedi Mourad , Danner Ronald P. , Duda J. Larry
Published: May 2003

The glass transition temperature of polymers and polymer solutions was approached through a combination of the group‐contribution, lattice‐fluid equation of state and the Gibbs–DiMarzio criterion. The model assumes zero entropy at the glass transition temperature and treats molecules as semiflexible chains. This stiffness is associated with a flex energy obtained from the glass transition temperature at atmospheric pressure. Whereas the application of the model is straightforward for homopolymers and polymer solutions, a new formalism using the dyad concept was developed for copolymers. It takes into account the copolymer composition as well as the sequencing of the monomers. The results obtained are consistent with experimental data. For polymer solutions, the model predictions are semiquantitative depending on the system. The interaction parameter required for binary systems was found to have little effect on the glass transition temperature predictions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 697–705, 2003
Phase separation behavior of poly(ether imide)/N,N‐dimethyl acetamide/nonsolvent systems
Authors: Shen Li‐Qiang , Xu Zhi‐Kang , Xu You‐Yi
Published: May 2003

The phase separation behavior of a poly(ether imide) (PEI)/N,N‐dimethyl acetamide (DMAc)/nonsolvent system was investigated. Three kinds of nonsolvents were used in the study: H2O, ethanol, and acetic acid (AA). It was found that the three systems (PEI/DMAc/H2O, PEI/DMAc/ethanol, and PEI/DMAc/AA) agree with the linearized cloud point (LCP) relation. The binodal lines of the three systems were calculated according to the LCP relation. The binodal line of the PEI/DMAc/(H2O + DMAc) system was also calculated according to the LCP relation of the PEI/DMAc/H2O system. The phase separation of the PEI/DMAc/(H2O + AA) system was studied, and the results agree with the LCP relation. These results can offer useful information for the establishment of dope and coagulation media using for the fabrication of a PEI membrane. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 875–881, 2003
Synthesis and characterization of amphiphilic hydroxypropylcellulose‐graft‐poly(ε‐caprolactone)
Authors: Shi Ruiwen , Burt Helen M.
Published: May 2003

An amphiphilic graft copolymer, hydroxypropylcellulose‐graft‐poly(ε‐caprolactone) (HPC‐g‐PCL), was synthesized by bulk polymerization without a catalyst and characterized with one‐dimensional and two‐dimensional NMR spectroscopy. Molar substitution of ε‐caprolactone on HPC (MSCL) was estimated by both gravimetry and 1H‐NMR, and the gravimetric method was considered suitable for MSCL determination. Heterogeneity in the HPC‐g‐PCL film was suggested by a microscopic study, and the existence of PCL‐rich crystalline regions was confirmed by the results of X‐ray diffraction and differential scanning calorimetry (DSC). The double endotherm observed in the DSC scans of HPC‐g‐PCL was associated with the different molecular weight fractions in the copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 718–727, 2003
Polyamide‐6‐b‐polybutadiene block copolymers: Synthesis and properties
Authors: Petrov P. , Jankova K. , Mateva R.
Published: May 2003

Polyamide‐6 (PA6)/polybutadiene (PB) block copolymers were synthesized with macroactivators (MAs) based on hydroxyl‐terminated polybutadiene functionalized with diisocyanates and having three N‐acyllactam chain‐growing centers per molecule. Two different diisocyanates, hexamethylene diisocyanate and isophorone diisocyanate, were applied as precursors for the MAs. The sodium salt of ε‐caprolactam was chosen as an initiator. The influence of the MA type and concentration on the anionic ring‐opening polymerization of ε‐caprolactam at 180°C was studied. A large percentage of the gel fraction in the copolymers was estimated, indicating crosslinked macromolecules. The structure and phase behavior of the copolymers were investigated with differential scanning calorimetry, wide‐angle X‐ray scattering, thermogravimetric analysis, and dynamic mechanical thermal analysis. In the copolymers, only the PA6 chains crystallized, and the crystallinity depended on the PB content. Different glass‐transition temperatures for the PB blocks and PA6 blocks were observed, indicating microphase separation in the copolymers. The mechanical properties of the copolymers were studied by notched impact testing and hardness measurements. The impact strength increased linearly with the soft component concentration up to 10 wt % and reached values six times higher than those of the PA6 homopolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 711–717, 2003
Synthesis and biodegradation of starch‐graft‐poly(hexylene adipate)
Authors: Zhu Changying , Kou Xiaodi , You Yingcai , Zhang Zhiqiang , Zuo Ju
Published: May 2003

Poly(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

The 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

The 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

To 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

A 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

Nitrile 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

Blends 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

Reversible 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

Reactive 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

A 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

This 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

The 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

A 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

Biodegradable 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

A 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

The 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

Fine 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
Determination of the crystalline phases of poly(vinylidene fluoride) under different preparation conditions using differential scanning calorimetry and infrared spectroscopy
Authors: Benz Marcel , Euler William B.
Published: May 2003

A method with good precision has been developed to quantitatively measure the degree of α‐, β‐, and γ crystallinity in poly(vinylidene fluoride) (PVDF) by means of infrared spectroscopy. The phase composition of solution‐deposited PVDF films was found to be strongly influenced by the presence of hydrophilic residues on the silicon substrate, the relative humidity present at film deposition, the spatial position on the substrate, and the thermal treatment of the deposited film. Films produced on pristine surfaces gave predominantly α‐phase PVDF, but when a layer of polar solvent (acetone or methanol) remained on the surface, the films produced were predominantly γ phase. Higher humidity promoted a higher fraction of γ crystallinity in the solution‐deposited PVDF films. Solution‐cast films had highly variable composition across the substrate, whereas spin‐cast films were uniform. High‐temperature annealing of PVDF films normally converts the polymer to the γ phase, but annealing the film while still attached to the silicon substrate inhibited this phase transformation. Low‐temperature annealing of freestanding films led to a previously unreported thermal event in the DSC, a premelting process that is a kinetic event, assigned to a crystalline relaxation. Higher‐temperature annealing gave a double endotherm, assigned to melting of different‐sized crystalline domains. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1093–1100, 2003
A comparative study of swelling properties of hydrogels based on poly(acrylamide‐co‐methyl methacrylate) containing physical and chemical crosslinks
Authors: Begam Tamanna , Nagpal A. K. , Singhal Reena
Published: May 2003

Poly (acrylamide‐co‐methyl methacrylate) hydrogels of different ratios were prepared by using chemical and physical crosslinks to study the effect of nature of crosslinks on swelling behavior of hydrogels. The chemically crosslinked gels were prepared by using NN′‐methylene bis acrylamide, while physically crosslinked hydrogels were prepared by precipitation polymerization method, using dioxane as solvent. Detailed swelling kinetics such as swelling ratio, transport exponent n, diffusion coefficient D and the effect of pH on equilibrium swelling studies. The study revealed that the nature of crosslinks alter the swelling characteristics of the hydrogel. In chemically crosslinked hydrogels the water transport is Fickian in nature, while in the case of the physically crosslinked hydrogels the water transport mechanism is anomalous indicating major change in relaxation mechanism due to nature of crosslinks. The results also indicate that with increasing acrylamide content the swelling ratio of the hydrogels were also increased, but the transport exponent n remains nearly constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 779–786, 2003
Chelation ion‐exchange properties of copolymer resin derived from 4‐hydroxyacetophenone, oxamide, and formaldehyde
Authors: Gurnule W. B. , Rahangdale P. K. , Paliwal L. J. , Kharat R. B.
Published: May 2003

A copolymer (4‐HAOF) prepared by condensation of 4‐hydroxyacetophenone and oxamide with formaldehyde in the presence of an acid catalyst proved to be a selective chelating ion‐exchange copolymer for certain metals. Chelating ion‐exchange properties of this copolymer were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+, Pb2+, and Hg2+ ions. A batch equilibrium method was employed in the study of the selectivity of metal‐ion uptake involving the measurements of the distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for Fe3+ ions than for Co2+, Zn2+, Cd2+, Pb2+, Cu2+, Ni2+, and Hg2+ ions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 787–790, 2003
Fourier transform rheometry on gum elastomers
Authors: Leblanc Jean L.
Published: May 2003

Using a modified torsional dynamic rheometer, strain and torque signals are captured and analyzed through Fourier transform. A thorough analysis of strain signal is first performed to document the quality of the applied deformation and to define the optimum conditions for signal capture, and hence, for Fourier transform calculation. A specific calculation procedure is developed that allows the error associated with FT calculation to be estimated, in terms of mean harmonic peaks and their standard deviation. Scatter is observed on low strain results that nearly vanishes when the applied deformation is larger than 14%, thus giving confidence in data gathered under non‐linear viscoelastic conditions. Results on a series of gum EPDM with different macromolecular characteristics (MWD and long chain branching, LCB) are reported and discussed, with respect to a simple four parameters model for the variation on deformation of the relative third harmonic component. Processing additives are found to mask expected LCB effects. Results on a series of SBR 1500 samples, collected from various manufacturers, are presented that illustrate the capability of FT rheometry to detect differences between materials expected to be similar. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1101–1115, 2003
Rheological behavior of ethylene–octene copolymer vulcanizates: Effect of blowing agent and precipitated silica filler
Authors: Nayak N. C. , Tripathy D. K.
Published: May 2003

An experimental study of the rheological behavior of ethylene–octene copolymer vulcanizates in extrusion containing blowing agent has been carried out. The cell morphology development has been studied through a scanning electron microscope. Rheological properties of unfilled and precipitated silica‐filled systems with variations of blowing agent, extrusion temperature, and shear rate have been studied by using a Monsanto processibility tester (MPT). The total extrusion pressure (PT), apparent shear stress (τwa), apparent viscosity (ηa), and die swell (%) of the unfilled and silica‐filled compounds have been determined by using MPT. The effect of blowing agent (ADC) on the rheological properties of the vulcanizates has also been investigated. There is a reduction of stress and viscosity with blowing agent loading. It was observed that the incorporation of a blowing agent led to decreased shear thinning behavior resulting in an increase in power law index. The viscosity reduction factor (VRF) of unfilled vulcanizates is found to be dependent on the concentration of the blowing agent, shear rate, and temperature, whereas VRF of silica‐filled vulcanizates is found to be dependent on shear rate, temperature, and blowing agent concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1132–1138, 2003
Synthesis, characterization, and metal ions adsorption properties of chitosan–calixarenes (I)
Authors: Li Hai‐Bing , Chen Yuan‐Yin , Liu Shi‐Lan
Published: May 2003

Calixarene‐modified chitosans (CTS–CA‐I and CTS–CA‐II) were first synthesized by the reaction of chitosan (CTS‐NH2) with 1,3‐bis‐chloroethoxyethoxy‐2,4‐dihydroxy‐p‐tert‐butylcalix[4]arene (CA‐I) or its benzoyl derivative (CA‐II). Their structures were characterized by infrared and X‐ray diffraction spectroscopy and scanning electron microscopy (SEM). The adsorption of Ni2+, Cd2+, Cu2+, Pd2+, Ag+, and Hg2+ by CTS–CA‐I and CTS–CA‐II was studied and the thermodynamic parameter of two calixarene‐modified chitosans toward Hg2+ was deduced. The adsorption properties of CTS–CA‐I and CTS–CA‐II were greatly varied compared with that CTS‐NH2, especially with the adsorption capacity toward Ag+ and Hg2+, because of the presence of the calixarene moiety. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1139–1144, 2003
Increased stability of polythiophene in the presence of aniline in acetonitrile
Authors: Pekmez Özçiçek Nuran , Pekmez Kadir , Holze Rudolf , Yıldız Attila
Published: May 2003

The conductance behavior of copolymers of aniline and thiophene with varying concentration ratios were studied in acetonitrile/tetrabutylammonium tetrafluoroborate using cyclic voltammetry and in situ conductance measurements. These studies revealed that compared with homopolymers, the copolymers have extended ranges of stability (even at very positive applied potentials), lower conductivities, and reversible doping/undoping characteristics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 862–866, 2003
Polyimides possessing bulky phosphorus groups: Synthesis and characterization
Authors: Liu Ying‐Ling , Hsu Chih‐Yuan , Wu Chuan‐Shao
Published: May 2003

A series of polyimides with bulky pendent groups containing phosphorus were obtained from polymerization of various dianhydrides with a new diamine (2DOPO‐A) bearing two bulky (9,10‐dihydro‐9‐oxa‐10‐oxide‐10‐phosphaphenanthrene‐10‐yl) (DOPO) substituents. The resulting polymers had inherent viscosities of 0.15–0.32 dL/g and glass transition temperatures of 260–283°C. The polyimides were soluble in some organic solvents due to the incorporation of bulky and polar DOPO groups. The non‐coplanar cardo structure of 2DOPO‐A also contributed to the improvement in the solubility of the polyimides. Incorporating DOPO groups into polyimides resulted in polymers with low initial decomposition temperatures (IDT; 310–362°C) due to the independent decomposition of the DOPO groups. Thermogravimetric analysis showed that the DOPO‐containing polyimides exhibited high integral procedural decomposed temperatures (IPDT) of 891–950°C. Incorporation of DOPO group into polyimides also improved their weight loss rate, thermal stability, thermal‐oxidative stability, and heat insulating property in the high temperature region. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 791–796, 2003
Physical and electroresponsive characteristics of the intercalated styrene‐acrylonitrile copolymer/clay nanocomposite under applied electric fields
Authors: Kim J. W. , Jang L. W. , Choi H. J. , Jhon M. S.
Published: May 2003

Styrene‐acrylonitrile copolymer (SAN)/clay nanocomposites were synthesized through an emulsion copolymerization of styrene and acrylonitrile in the presence of sodium montmorillonite, and their physical properties and electroresponsiveness under an applied electric field were characterized. Thermogravimetric analysis (TGA) showed that the thermal stability of the synthesized polymer was sustained. X‐ray diffraction (XRD) analysis confirmed the insertion of SAN into the interlayers of clay, whose separation consequently increased, as compared to those of the pristine clay. Transmission electron microscopy (TEM) was used to observe the suspended state of clay. Dry‐base electrorheological (ER) fluids were prepared by mixing intercalated SAN nanocomposite particles into silicone oil. Typical ER behavior, i.e., enhancement of shear and yield stresses in the presence of an applied electric field, was observed using a rotational rheometer equipped with a high‐voltage generator. A universal yield stress scaling equation was also found to fit our experimental data well. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 821–827, 2003
Surfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) prepared with poly(L‐lactide)/ poly(ethylene glycol)
Authors: Jeong Young‐Il , Shim Yong‐Ho , Choi Changyong , Jang Mi‐Kyeong , Shin Gil Man , Nah Jae‐Woon
Published: May 2003

Surfactant‐free nanoparticles of poly(DL‐lactide‐co‐glycolide) (PLGA) nanoparticles were prepared with or without poly(L‐lactide)‐poly(ethylene oxide) (LE) diblock copolymer (abbreviated as PLGA/LE and PLGA nanoparticles) by dialysis method. LE diblock copolymer was used to make PLGA nanoparticles to alternate conventional surfactant. The size of PLGA and PLGA/LE nanoparticles was 295.3 ± 171.3 and 307.6 ± 27.2 nm, respectively, suggesting LE diblock copolymer might be coated onto the surface of nanoparticles. Observation of scanning electron microscope (SEM) showed that PLGA/LE nanoparticles have spherical shapes ranging ∼ 200–500 nm. In 1H‐NMR study, characteristic peaks of the methyl protons of PLGA disappeared in D2O, whereas characteristic peaks of the methyl proton of both PEG and PLGA were shown in both CDCl3 and D2O, indicating that LE diblock copolymer coated on the surface of the PLGA nanoparticles. The higher the initial content of drug, the higher the drug contents and the lower the loading efficiency. PLGA/LE nanoparticles at higher drug contents resulted in slower adriamycin·HCl (ADR) release rate than that of lower drug contents. Also, slower release rate of ADR was achieved by entrapped into the PLGA/LE nanoparticles, whereas LE polymeric micelles showed rapid ADR release. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1116–1123, 2003