bluuebunny/crossref_metadata_2025 huggingface dataset:
Cover Picture: DNA Topoisomerase Inhibitor Acutissimin A and Other Flavano‐Ellagitannins in Red Wine (Angew. Chem. Int. Ed. 48/2003)
Authors: Quideau Stéphane , Jourdes Michael , Saucier Cédric , Glories Yves , Pardon Patrick , Baudry Christian
Published: December 2003

Human DNA topoisomerase II is inhibited in vitro by acutissimin A, a flavano‐ellagitannin, with an activity much higher than that of the clinically used antitumor drug etoposide. Acutissimin A is formed by a non‐enzymatic, yet diastereoselective, condensation reaction occurring during the aging of red wine in oak barrels. S. Quideau et al. report its high‐yielding semi‐synthesis in their Communication on page 6012 ff.
High‐conversion catalytic chain transfer polymerization of methyl methacrylate
Authors: Pierik S. C. J. , Herk A. M. van
Published: December 2003

In this work the effects of conversion on the apparent catalyst activity in the catalytic chain transfer polymerization of methyl methacrylate are reported. Several mechanisms are discussed that may explain the experimental observations. The discussion is supported with computer simulations using Predici software. It is shown that the experimental decrease in weight average molecular weight with conversion is smaller than the decrease obtained in simulations. The most likely cause for this discrepancy is slow catalyst deactivation. The half‐life of CoBF under the reported conditions was determined to be about 10 h. Furthermore, the effect of acetic acid (HAc) and benzoyl peroxide (BPO) on the evolution of the molecular weight distribution is investigated. Both HAc and BPO enhance catalyst deactivation. For HAc, catalyst deactivation scales with the square root of its concentration. BPO‐ enhanced deactivation depends linearly on its concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1375–1388, 2004
Degradation of polyethylene during extrusion. II. Degradation of low‐density polyethylene, linear low‐density polyethylene, and high‐density polyethylene in film extrusion
Authors: Andersson Thorbjörn , Stålbom Berit , Wesslén Bengt
Published: December 2003

The degradation of different polyethylenes—low‐density polyethylene (LDPE), linear low‐density polyethylene (LLDPE), and high‐density polyethylene (HDPE)—with and without antioxidants and at different oxygen concentrations in the polymer granulates, have been studied in extrusion coating processing. The degradation was followed by online rheometry, size exclusion chromatography, surface oxidation index measurements, and gas chromatography–mass spectrometry. The degradations start in the extruder where primary radicals are formed, which are subject to the auto‐oxidation when oxygen is present. In the extruder, crosslinking or chain scissions reactions are dominating at low and high melt temperatures, respectively, for LDPE, and chain scission is overall dominating for the more linear LLDPE and HDPE resins. Additives such as antioxidants react with primary radicals formed in the melt. Degradation taking place in the film between the die orifice, and the quenching point is mainly related to the exposure time to air oxygen. Melt temperatures above 280°C give a dominating surface oxidation, which increases with the exposure time to air between die orifice and quenching too. A number of degradation products were identified—for example, aldehydes and organic acids—which were present in homologous series. The total amount of aldehydes and acids for each number of chain carbon atoms were appeared in the order of C5>C4>C6>C7≫C2 for LDPE, C5>C6>C4>C7≫C2 for LLDPE, and C5>C6>C7>C4≫C2 for HDPE. The total amounts of oxidized compounds presented in the films were related to the processing conditions. Polymer melts exposed to oxygen at the highest temperatures and longest times showed the presence dialdehydes, in addition to the aldehydes and acids. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1525–1537, 2004
Blends of plasticized poly(vinyl chloride) and waste flexible poly(vinyl chloride) with waste nitrile rubber powder
Authors: Ghaisas S. S. , Kale D. D. , Kim J. G. , Jo B. W.
Published: December 2003

Blends of poly(vinyl chloride) (PVC) with varying contents of plasticizer and finely ground powder of waste nitrile rubber rollers were prepared over a wide range of rubber contents through high‐temperature blending. The effects of rubber and plasticizer (dioctyl phthalate) content on the tensile strength, percentage elongation, impact properties, hardness, abrasion resistance, flexural crack resistance, limiting oxygen index (LOI), electrical properties, and breakdown voltage were studied. The percentage elongation, flexural crack resistance, and impact strength of blends increased considerably over those of PVC. The waste rubber had a plasticizing effect. Blends of waste plasticized PVC and waste nitrile rubber showed promising properties. The electrical properties and LOI decreased with increasing rubber and plasticizer content. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1552–1558, 2004
Lifetime assessment of epoxies by the kinetics of thermal degradation
Authors: Stutz Herbert
Published: December 2003

The kinetics of thermal degradation of 4,4′‐diaminodiphenylsulfone (DDS)‐cured glycidylethers (DGBA) and glycidylamines (TGDDM) have been studied by isothermal annealing. Thermal degradation proceeds via first‐order kinetics with activation energies of 138 (DGBA/DDS) and 95 kJ/mol (TGDDM/DDS). From these data the temperature‐dependent lifetime can be calculated. Based on the heat distortion temperature and 20 years' service as criteria, the upper service temperature is found to be around 115–120°C. In spite of the different activation energies and bond stabilities, only marginal differences in the upper allowed service temperatures between these resins were found. Only slight improvements can be expected by optimizing the cure conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1881–1886, 2004
Miscibility and specific interactions in blends of poly(vinyl phenyl ketone hydrogenated) with poly(2,6‐dimethyl‐1,4‐phenylene oxide)
Authors: Maldonado‐Santoyo M. , Nuño‐Donlucas S. M. , Cesteros L. C. , Katime I.
Published: December 2003

The miscibility behavior of poly(vinyl phenyl ketone hydrogenated) (PVPhKH) and poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) are studied by differential scanning calorimetry, thermomechanical analysis, and FTIR spectroscopy. Two miscibility windows between 10 to 40 and 60 to 90 wt % PPO are detected. Only the blend with 50 wt % PPO is immiscible. The best fit of the Gordon–Taylor equation of the experimental glass‐transition temperatures for miscible PVPhKH/PPO blends is shown. A study by FTIR spectroscopy suggests that hydrogen bonding interactions are formed between the hydroxyl groups of PVPhKH and the ether groups of PPO. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1887–1892, 2004
Surface free‐energy analysis of poly(N‐vinyl‐2‐pyrrolidone–crotonic acid) copolymers prepared by γ‐ray‐induced polymerization technique
Authors: Çaykara Tuncer , Yerlikaya Zekeriya , Kantoğlu Ömer
Published: December 2003

Pure poly(N‐vinyl‐2‐pyrrolidone) (PVP) and P(VP–crotonic acid) [P(VP/CrA)] copolymers with different CrA contents were prepared by the γ‐ray‐induced polymerization technique. The change in the surface free energy of the copolymers was investigated using the Van Oss–Good contact angle evaluation methodology in order to estimate their wettability properties. The apolar Lifshitz–van der Waals component (γ) and the electron donor component (γ) of the PVP network were calculated as 27.6 and 56.5 mN m−1, respectively. In this case, the surface of the PVP network had a basic character (electron donor). By contrast, the γ component of P(VP/CrA) copolymers increased and then remained almost constant with increasing CrA content. In addition, the surface of these copolymers changed from a basic character (γ = 56.5 mN m−1) to an acidic character (γ = 0.07 mN m−1) with increasing CrA contents in the copolymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1893–1897, 2004
Rheological behavior of reactive blending of epoxidized natural rubber with cassava starch and epoxidized natural rubber with natural rubber and cassava starch
Authors: Nakason C. , Kaesaman A. , Sainamsai W. , Kiatkamjonwong S.
Published: December 2003

Epoxidized natural rubbers (ENR‐25 and ENR‐45) were prepared using the performic epoxidation method. Two‐component (ENR–cassava starch) and three‐component (ENR–NR–cassava starch) blends were prepared. ENR‐25 and ENR‐45 were blended with various quantities of gelatinized cassava starch in the latex state. The pure ENR exhibited lower shear stress and shear viscosity than those of the blends with cassava starch. Furthermore, the shear stress and shear viscosity were increased with an increase in the cassava starch concentration. The chemical interaction between the epoxide groups in the ENR and the hydroxyl groups in the cassava starch molecules might be the reason for the increasing trends of the shear stress and shear viscosity. The blends are classified as compatible blends because of the strong chemical bonding between different phases. SEM micrographs were used to clarify the compatibility. Power law behavior with pluglike flow profiles was observed for all sets of ENR–NR–cassava starch blends. Very low power law index values (<0.34) and highly pseudoplastic fluid behavior were also observed. The log additive rule was applied to plots of zero shear viscosity (consistency index) and the shear viscosity versus the concentration of ENR‐25. Positive deviation blending was observed, which indicates compatible blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1752–1762, 2004
Characterization of mechanical properties of γAl2O3 dispersed epoxy resin cured by γ‐ray radiation
Authors: Jin Kim Dong , Hyun Kang Phil , Chang Nho Young
Published: December 2003

Epoxy resins are widely utilized as high performance thermosetting resins for many industrial applications, but they are characterized by relatively low toughness. Incorporation of rigid inorganics is suggested to improve the mechanical properties of epoxy resins. An attempt is made to disperse nanosized γ‐Al2O3 particles into diglycidyl ether of bisphenol A epoxy resins for the improvement of the mechanical properties. These hybrid epoxy–alumina composites are prepared using by the γ‐ray curing technique conducted at 100 kGy under nitrogen at room temperature. The composites are characterized by determining the gel content, flexural strength, Youngis modulus, and toughness at room temperature using scanning electron microscopy and FTIR studies. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1898–1903, 2004
Treatment of Caribbean pine by in situ polymerization of styrene and furfuryl alcohol
Authors: Magalhães Washington Luiz Esteves , da Silva Renato Romano
Published: December 2003

Caribbean pine impregnated by the full cell treatment schedule with styrene, furfuryl alcohol (FFA), and styrene–FFA monomers was cured for 48 h at 100°C. Styrene did not penetrate inside the wood cell wall; instead, it adhered on the cell wall surfaces and fill cell lumens. The volume contraction during the formation of polystyrene causes the volume contraction of the wood sample. The permanent volumetric swelling is attained only for samples treated with FFA, which is caused by cell wall impregnation. The dimensional stability of the treated wood samples is evaluated with the antiswell efficiency coefficient (ASE). The water repellency is expressed as the water‐repellent effectiveness (WRE). Treatment with styrene improves the water repellence, whereas a double treatment increases the dimensional stability. Lixiviation slightly affects the ASE and WRE coefficients. The treatments improve the Shore D hardness in comparison to untreated wood. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1763–1769, 2004
Compatibilization of nitrile‐butadiene rubber/ethylene‐propylene‐diene monomer blends by mercapto‐modified ethylene‐vinyl acetate copolymers
Authors: Oliveira Marcia G. , Soares Bluma G.
Published: December 2003

Mercapto‐modified ethylene‐vinyl acetate (EVASH) has been employed as a reactive compatibilizing agent for nitrile‐butadiene rubber (NBR)/ethylene‐propylene‐diene monomer (EPDM) blends vulcanized with a sulfur/2,2′‐dithiobisbenzothiazole (MBTS) single accelerator system and a (sulfur/MBTS/tetramethylthiuram disulfide (TMTD) binary accelerator system. The addition of 5.0 phr EVASH resulted in a significant improvement in the tensile properties of blends vulcanized with the sulfur/MBTS system. In addition to better mechanical performance, these functionalized copolymers gave rise to a more homogeneous morphology and, in some cases, better aging resistance. The compatibilization was not efficient in blends vulcanized with the S/MBTS/TMTD binary system, probably because of the faster vulcanization process occurring in this system. The good performance of these EVASH samples as compatibilizing agents for NBR/EPDM blends is attributed to the higher polarity of these components that is associated with their lower viscosity. Dynamic mechanical analysis also suggested a good interaction between the phases in the presence of EVASH. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1404–1412, 2004
Drawing properties of ultrahigh molecular weight polyethylene fibers prepared at varying formation temperatures
Authors: Yeh Jen‐Taut , Lin Yue‐Tang , Jiang Huang‐Bin
Published: December 2003

The values of the percentage crystallinity, melting temperature, birefringence, and cross‐sectional area of ultrahigh molecular weight polyethylene (UHMWPE)/low MWPE (LMWPE) as‐prepared fiber specimens are reduced consistently as the formation temperatures decreased from 60 to 0°C. Much more sparse structures with significantly larger voids are found on the fractured surfaces of those as‐prepared fibers that were prepared at higher formation temperatures than those prepared at lower formation temperatures. The cross sections of the as‐prepared fiber specimens gradually change from an oblate to a nearly circular to an uneven circular shape as the formation temperatures are reduced from 60 to 10 to 0°C, respectively. It is worth noting that the achievable draw ratios (Dra) of the as‐prepared fibers reach maximum when they are prepared at an optimum formation temperature of 10°C. Moreover, the Dra values of the as‐prepared fiber (UL10) specimens can be further improved by using a two‐stage drawing process, wherein the temperature used in the second drawing stage (Tsec) is higher than 95°C. In fact, the optimum Tsec of the two‐stage drawn UL10 fiber specimens increases significantly from 105 to 115°C as the first‐stage draw ratio (Dlr) values increase from 20 to 40, respectively. The birefringence values, tensile strengths, and moduli of one‐ and two‐stage drawn UL10 fiber specimens increase consistently with increasing draw ratios, although the increasing rate of these values is gradually reduced as the draw ratios are greater than certain values. In contrast, at a constant draw ratio, the two‐stage drawn UL10 fiber specimens drawn at a higher Tsec always exhibit higher values of birefringence, tensile strengths, and moduli than those with the same Dlr but drawn at a lower Tsec. Moreover, at a constant draw ratio, the birefringence values, tensile strengths, and moduli of the fiber specimens drawn at a fixed optimum Tsec reach the maximum when they are first drawn up to an optimum Dlr of about 50. In fact, by using the proper optimum Tsec and Dlr, the tensile strengths and moduli of the two‐stage drawn UL10 fiber specimens can reach more than 11 and 155 GPa, respectively. The possible mechanisms accounting for these interesting properties are proposed in this study. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1559–1570, 2004
Crosslinking of polyvinyl chloride by electron beam irradiation in the presence of ethylene–vinyl acetate copolymer
Authors: Wang Shifeng , Zhang Yong , Zhang Yinxi , Zhang Changming , Li Enjun
Published: December 2003

Electron beam (EB) irradiation of polyvinyl chloride (PVC) was carried out in the presence of three different ethylene–vinyl acetate copolymers (EVA). The mechanical properties of the original and irradiated blends were tested. The gel content measurement, chlorine loss upon electron irradiation, and gel permeation chromatograph (GPC) were used to characterize the effect of EVA on the irradiation behavior of PVC/EVA blends. The content and the chemical structure of EVA in the blends had considerable effects on the mechanical properties and gel content of the blends. The incorporation of EVA into PVC blend can increase the gel content and reduce chlorine loss of the blends. The GPC analysis of the soluble part in the irradiated PVC samples showed that the addition of EVA into the PVC blend lowered the polydispersity of molecular weight of PVC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1571–1575, 2004
Damping of vinyl acetate–n‐butyl acrylate copolymers
Authors: Chu Hou‐Hsein , Lee Chi‐Ming , Huang W. G.
Published: December 2003

A photopolymerization process at room temperature was devised to copolymerize vinyl acetate (VAc) and n‐butyl acrylate (BA) mainly to prepare rubber‐like damping sheet bearing pressure‐sensitive adhesive property in this study. The investigations using both the differential scanning calorimeter and rheometric dynamic analysis show the existence of two glass transition temperatures for each copolymer. The scanning electron microscopic pictures reveal that the degree of microphase separation increases with increasing annealing time at 70°C. It was suggested that the rubbery domain (formed by the PBA blocks) disperses in the glassy domain (constituted by the PVAc blocks), making an effective damping entity. Excellent damping was observed for the copolymer samples, with the tanδ peak values as high as 1.76–1.80 at a certain temperature range and with tanδ> 0.3 at quite wide temperature ranges. In addition, the copolymers containing more VAc tend to have the higher damping. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1396–1403, 2004
Linear polymers with sulfur in the main chain. II. Synthesis of polyesters by interfacial polycondensation of bis(4,4′‐hydroxyphenyl)sulfide with several aliphatic acid dichlorides and their properties
Authors: Hirano Hiroshi , Watase Seiji , Tanaka Mitsuaki
Published: December 2003

The synthesis and properties of sulfur‐containing polyesters derived from bis(4,4′‐hydroxyphenyl)sulfide (TDP) and various acid dichlorides (AC) have been studied to evaluate the effect of the incorporation of sulfur in the main chains of polyesters. Polyesters derived from TDP and AC (with methylene numbers of 2–10) were synthesized by interfacial polycondensation in a 1,1,2,2‐tetrachloroethane /water mixture using tetra‐n‐butyl ammonium bromide as a phase transfer catalyst. Through the use of gel permeation chromatography, it was determined that the polyesters thus obtained had high molecular weights. The thermal properties of the polyesters including the TDP moiety were evaluated by thermogravimetry/differential thermal analysis and by differential scanning calorimetry. The analyses indicated that the polyesters including the TDP moiety were crystalline polymers with relatively high heat resistance. These polyesters were found to show an odd–even effect with the glass transition temperature and the melting point based on the methylene numbers. The tensile strength and storage modulus decreased with the methylene numbers. It was further found that the polyesters evidenced excellent barrier properties towards oxygen gas having an odd–even effect. In particular, it was shown that the polyesters with methylene numbers of 3, 4, 6, and 8 of methylene units have lower oxygen permeability than poly(ethylene terephthalate) (PET).©2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1865–1872, 2004
Inhibitor radicals in styrene polymerization
Authors: Motyakin M. V. , Wasserman A. M. , Stott P. E. , Zaikov G. E.
Published: December 2003

Stable radicals derived from inhibitor molecules were detected in the process of styrene polymerization. N‐(1,4‐dimethylpentyl)‐4‐nitroso‐aniline and 2,4‐dinitrophenol inhibitors were shown to produce nitroxyl radicals. Phenoxyl radicals come from 4‐benzylidene‐2,6‐di‐tert‐butyl‐cyclohexa‐2,5‐dienone. The radical structures were determined. The kinetics of radical formation was studied. These radicals can participate in the process of living radical polymerization and significantly affect the kinetics of polymerization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1599–1603, 2004
Influence of processing on structure of β‐nucleated poly(propylene) fibers
Authors: Broda Jan
Published: December 2003

Fibers colored with quinacridone pigment spun at low take‐up velocities were obtained. The spun fibers, with a very high β‐form content, were drawn at room temperature and at a temperature of 120°C at different draw ratios. They were then heat stabilized at different temperatures, ranging from 140 to 150°C for different time intervals. As a result of drawing, the transition from β to mesophase, as well as that from β to α, was observed. The β to mesophase transition results from cold drawing at room temperature, while the β to α transition results from drawing at 120°C. In both cases, the significant decrease of β‐form content occurs at the low draw ratio of 2. At higher draw ratios, the β‐form content gradually decreases, and at a draw ratio of 7 the β‐form disappears altogether. As a result of heat stabilization, the β to α transformation was observed. The first change of the β‐form content was noticed at 140°C. For fibers stabilized at temperatures above 140°C, the decrease of the β‐form content is more significant and increases with the increase of the stabilization temperature. At 150°C, a rapid drop of the β‐form content occurs after only 3 min, and after a few more minutes the β‐form disappears. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1413–1418, 2004
Synthesis and electrorheology of potato starch phosphate
Authors: Park Dong P. , Sung Jun H. , Kim Chul Am , Choi Hyoung J. , Jhon Myung S.
Published: December 2003

Potato starch phosphate (PSP) particles were synthesized via an esterification process of potato starch with a mixture of various concentrations of phosphoric acid and urea. The electrorheological (ER) characteristics of the synthesized PSP particles, suspended in a silicone oil, were examined. The PSP granule‐based ER fluid exhibited typical ER behavior, possessing a nonvanishing yield stress under an applied electric field. Enhanced polarization and higher yield stresses were observed as the content of phosphate groups in the starch increases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1770–1773, 2004
Thiophosphoryl disulfides as crosslinking agents for chloroprene rubber
Authors: Das Amit , Naskar Nityananda , Basu Dipak Kumar
Published: December 2003

The objective of this investigation was the determination of a suitable substitute for ethylene thiourea (ETU), a well‐known vulcanizing agent for polychloroprene rubber (CR). Unfortunately, ETU is a potent carcinogenic compound, and so its replacement is needed. The efficacy of several thiophosphoryl disulfides as crosslinking agents for CR, either alone or in combination with other compounds, was examined. It was shown that bis(diisopropyl)thiophosphoryl disulfide (DIPDIS) and bis(dicyclohexyl)thiophosphoryl disulfide (DCHDIS), being ecofriendly, could be replacements. Additionally, these thiophosphoryl compounds were shown to provide significant antioxidant protection. CR vulcanizates containing DIPDIS or DCHDIS exhibited higher tensile strengths than those containing ETU. Bis(3‐ethoxysilylpropyl) tetrasulfide imparted to CR vulcanizates a notable modulus, which was comparable to that obtained with ETU‐cured products. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1913–1919, 2004
Coating of porous silica beads by in situ polymerization/crosslinking of 2‐hydroxypropyl β‐cyclodextrin for reversed‐phase high performance liquid chromatography applications
Authors: Carbonnier B. , Janus L. , Lekchiri Y. , Morcellet M.
Published: December 2003

Porous silica beads were coated with a crosslinked β‐cyclodextrin polymer by in situ polymerization/crosslinking of 2‐hydroxypropyl β‐cyclodextrin with 1,6‐hexamethylenediisocyanate in anhydrous dimethylsulfoxide. This method was developed for the preparation of reversed‐phase high performance liquid chromatography stationary phases. The mass of polymer immobilized onto the silica surface was controlled by the amount of coupling agent, 1,6‐hexamethylenediisocyanate, added during the coating process. The influence of the polymer coating on the physical features of the beads was investigated by means of nitrogen adsorption/desorption methods, scanning electron microscopy and energy dispersion X‐ray analysis. The column lifetime was found to be primarily dependent on the extent of crosslinking of the stationary phase. Moreover, it was demonstrated that the synthesis of highly crosslinked stationary phases with a reasonable column lifetime gave rise to a phase separation of the β‐cyclodextrin polymer. To prove their usefulness as reversed‐phase packing materials, they were used to separate mixtures of nitrophenol positional isomers, four pesticides, and drugs. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1419–1426, 2004
Effect of different film preparation procedures on the thermal, morphological and mechanical properties of pure and calcite‐filled HDPE films
Authors: Kundu Patit P. , Biswas Jagannath , Kim Hyun , Chung Chee‐Won , Choe Soonja
Published: December 2003

The effect of different film preparation procedures on the thermal, morphological and mechanical properties of high density polyethylene (HDPE) films have been studied using differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and ultimate tensile testing. Film preparation procedures included variation in cooling methods, including quenching, forces (fanning) and natural cooling and techniques such as extrusion followed by melt squeezing and compression molding. The heat of fusion (from DSC), the degree of crystallinity (from WAXRD) and the crystallite size (from WAXRD and AFM) were found to be highest for naturally cooled specimens, followed by fan‐cooled and quenched ones. AFM images of surface topology exhibit stacked lamellar morphology for forcefully cooled (fan‐cooled and quenched) samples and spherulitic ‘lozenges’ for naturally cooled ones. The Young's modulus and yield stress [from the universal testing machine (UTM)] were highest for naturally cooled samples, followed by fan‐cooled and quenched ones. Among the calcite‐filled composites, the ‘base film,’ which was prepared by extrusion followed by melt squeezing and natural cooling, exhibited the lowest heat of fusion and degree of crystallinity and a similar crystallite size relative to compression‐molded films. Lower yield stress, tensile strength and Young's modulus and higher elongation at break were observed for the base film in comparison to the naturally cooled composite film. The low degree of crystallinity and crystallite size in the ‘base film’ explain all of its mechanical and morphological properties. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1427–1434, 2004
Volume strain changes of plasticized poly(vinylidene fluoride) during tensile and creep tests
Authors: Cangemi L. , Elkoun S. , G'Sell C. , Meimon Y.
Published: December 2003

The volume strain changes of plasticized poly(vinylidene fluoride) during tensile and creep tests were characterized. A negative volume strain was observed. This phenomenon was ascribed to compaction taking place during mechanical testing, which further delayed the onset of plastic instability and, therefore, the cavitation process. It was suggested that this compaction was caused by the orientation of amorphous chain segments leading to material densification. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1784–1791, 2004
Study on isotactic polypropylene/zinc‐neutralized sulfonated ethylene propylene diene monomer rubber/CaCO3 ternary blends
Authors: Zheng Mingjia , Li Huilin
Published: December 2003

The morphological structure and mechanical properties of isotactic polypropylene (PP)/zinc‐neutralized sulfonated ethylene propylene diene monomer rubber (ZnSEPDM)/CaCO3 blends were studied. PP/ZnSEPDM/CaCO3 blends were prepared through two different sequences. A: Blending PP with ZnSEPDM, then adding CaCO3; B: Blending ZnSEPDM with CaCO3, then adding PP. The blending sequence has substantial influence on the mechanical properties. SEM micrographs and X‐ray photoelectron spectrometry indicate that the CaCO3 filler is encapsulated by ZnSEPDM in those blends prepared through sequence B, which caused an extra increase of impact strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1635–1640, 2004
Dry‐peelable temporary protective coatings from waterborne self‐crosslinkable sulfourethane–silanol dispersions
Authors: Lewandowski Kevin , Krepski Larry R. , Mickus Daniel E.
Published: December 2003

Novel temporary protective coatings were prepared by the addition of release additives to waterborne polyurethane dispersions. New types of self‐crosslinkable sulfourethane–silanol (SUS) dispersions were utilized as the peelable coatings. These dispersions are stable, low‐volatility organic chemical (VOC) waterborne dispersions that spontaneously crosslink upon drying without extra additives or processing steps. Tensile strengths up to 6000 psi with elongations between 300–600% were obtained for the crosslinked films. The adhesion of the films to a variety of substrates can be controlled by the addition of hydrophilic additives, including glycerol, oligomers of glycerol, and poly(ethylene glycol) derivatives. Alternatively, hydrophobic additives that are water dispersible, such as paraffin waxes and sulfated castor oil, can also be used to control adhesion. In addition, this technique can be utilized for the release of films derived from a wide variety of waterborne urethane dispersions, including carboxylated polyurethane ureas. The removable coatings are useful for the temporary protection of plastic surfaces during thermoforming processes. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1443–1449, 2004
Preparation and characterization of thermosensitive beads with macroporous structures
Authors: Ni Caihua , Wang Zheng , Zhu Xiao Xia
Published: December 2003

Thermosensitive copolymers of poly(N‐isopropyl acrylamide)‐co‐2‐hydroxyethyl methacrylate (NIPA‐co‐HEMA) macroporous resins were synthesized in the form of beads by inverse suspension polymerization. The copolymerization was carried out in aqueous solutions of the comonomers dispersed by cyclohexane with stabilizers. A series of resins with different molar ratios of NIPA : HEMA, and different crosslinking degrees was obtained. The compositions of the copolymers were determined by elemental analysis. The results showed that the content of HEMA in a copolymer was higher than that of the corresponding feed mixture from which the copolymer was made. IR spectra also confirmed the structure of the copolymers. The porous parameters such as true densities, apparent densities, pore volumes, and porosities of the resins were measured by means of pycnometry. The determination of equilibrium swelling ratios and measurement of differential scanning calibration indicated that the resins exhibited thermosensitivity in aqueous solutions. Finally, the loading of hydroxyl groups was determined by titration. The resins have potential applications as supports in solid‐phase synthesis after being functionalized. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1792–1797, 2004
Study on the dynamic self‐organization of montmorillonite in two phases
Authors: Wang Shaofeng , Hu Yuan , Song Lei , Liu Jie , Chen Zuyao , Fan Weicheng
Published: December 2003

Polycarbonate (PC)/acrylonitrile–butadiene–styrene (ABS) polymer alloy/montmorillonite (MMT) and nylon 6 (PA6)/ABS polymer alloy/MMT nanocomposites were prepared using the direct melt intercalation technique. Their structures were characterized by XRD and TEM. The results of TEM show that the silicate layers dispersed differently in two phases. In the PC/ABS/MMT nanocomposite, the silicate layers were self‐organized in the ABS phase, whereas in the PA6/ABS/MMT nanocomposite, the silicate layers were dispersed in both phases but mainly in the PA6 phase. Furthermore, the PC/MMT nanocomposite was melt‐mixed with pure ABS, and the changed morphology of the hybrid with the change of melt‐mixing time was characterized by XRD and TEM, to study the dynamic self‐assembly of clay layers in two phases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1457–1462, 2004
Study of poly(trimethylene terephthalate) as an engineering thermoplastics material
Authors: Zhang Jialiang
Published: December 2003

Poly(trimethylene terephthalate) (PTT) was systematically studied as an engineering thermoplastics material. Crystallization rates, crystalline degrees, and mechanical properties of two commercial PTT polymers and one glass fiber–reinforced PTT compound were investigated and compared with those of poly(butylene terephthalate) (PBT). PTT raw polymers have crystallization temperature (Tc) values around 152°C, and their kneaded polymers show Tc values of about 177°C, about 15°C lower than the values of PBT polymers used in this study. From the exothermic heat values of DSC measurements, both PTT and PBT show the crystalline degree order greater than 30%. Injection‐molded PTT specimens and PBT specimens exhibit crystalline degrees from 18 to 32% and 23.8 to 30%, respectively. PTT polymers show higher tensile and flexural strengths, but lower impact strengths and elongations than those of PBT polymers. The low elongation behavior of PTT does not change with the intrinsic viscosity and the molder temperature. PTT‐GF30 promotes better mechanical properties than those of PBT‐GF30, close to those of PET‐GF30. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1657–1666, 2004
Preparation and characterization of poly(L‐lactide)/ poly(ϵ‐caprolactone) fibrous scaffolds for cartilage tissue engineering
Authors: Zhao Jin , Yuan Xiaoyan , Cui Yuanlu , Ge Quanbo , Yao Kangde
Published: December 2003

Polyblend fibrous scaffolds in mass ratios of 100/0, 90/10, 80/20, and 70/30 from poly(L‐lactide) (PLLA) and poly(ϵ‐caprolactone) (PCL) for cartilage tissue engineering were prepared in three steps: gelation, solvent exchanging, and freeze‐drying. Effects of the blend ratio, the exchange medium, and the operating temperature on the morphology of scaffolds were investigated by SEM. PLLA/PCL scaffolds presented an ultrafine fibrous network with the addition of a “small block” structure. Smooth and regular fibrous networks were formed when ethanol was used as the exchange medium. Properties of the scaffolds, such as thermal and mechanical properties, were also studied. The results suggested that the compressive modulus declined as PCL amount increased. The incorporation of PCL effectively contributed to reduce the rigidity of PLLA. Bovine chondrocytes were seeded onto PLLA/PCL scaffold. Cells attached onto the fibrous network and their morphology was satisfactory. This polyblend fibrous scaffold will be a potential scaffold for cartilage tissue engineering. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1676–1684, 2004
UV‐radiation–induced preirradiation grafting of methyl methacrylate onto lignocellulose fiber in an aqueous medium and characterization
Authors: Khan Ferdous , Ahmad S. R. , Kronfli E.
Published: December 2003

The preirradiation method of grafting has been established by ultraviolet radiation. Methyl methacrylate (MMA) was grafted onto jute fiber in an aqueous medium. The variation of graft weight with UV‐radiation time, monomer concentration, and reaction time was investigated. The conversion of monomer into homopolymer and graft copolymer was evaluated. The graft weight passes through a maximum value (∼ 122%) with UV‐radiation time. The optimum value of the monomer concentration was evaluated for maximum degree of grafting. Graft copolymerization of MMA onto lignocellulose fiber significantly increases the elongation at break (∼ 65%) compared to that of the “as‐received” sample. However, a linear decrease on breaking load was observed with the increase of graft weight. The estimation of degree of grafting was achieved using an IR technique by correlating band intensities with the degree of grafting. Considering the water‐absorption property, the grafted sample showed a maximum up to 61% decrease in hydrophilicity compared to that of the as‐received sample. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1667–1675, 2004
Effect of the addition of acrylonitrile/ethylene–propylene–diene monomer (EPDM)/styrene graft copolymer on the morphology–properties relationships in poly(styrene‐co‐acrylonitrile)/EPDM rubber blends
Authors: Qu Xiongwei , Shang Shurui , Liu Guodong , Zhang Shengwen , Zhang Yan , Zhang Liucheng
Published: December 2003

Blends of poly(styrene‐co‐acylonitrile) (SAN) with ethylene–propylene–diene monomer (EPDM) rubber were investigated. An improved toughness–stiffness balance of the SAN/EPDM blend was obtained when an appropriate amount of acrylonitrile–EPDM–styrene (AES) graft copolymer was added, prepared by grafting EPDM with styrene–acrylonitrile copolymer, and mixed thoroughly with both of the two components of the blend. Morphological observations indicated a finer dispersion of the EPDM particles in the SAN/EPDM/AES blends, and particle size distribution became narrower with increasing amounts of AES. Meanwhile, it was found that the SAN/EPDM blend having a ratio of 82.5/17.5 by weight was more effective in increasing the impact strength than that of the 90/10 blend. From dynamic mechanic analysis of the blends, the glass‐transition temperature of the EPDM‐rich phase increased from −53.9 to −46.2°C, even −32.0°C, for the ratio of 82.5/17.5 blend of SAN/EPDM, whereas that of the SAN‐rich phase decreased from 109.2 to 108.6 and 107.5°C with the additions of 6 and 10% AES copolymer contents, respectively. It was confirmed that AES graft copolymer is an efficient compatibilizer for SAN/EPDM blend. The compatibilizer plays an important role in connecting two phases and improving the stress transfer in the blends. Certain morphological features such as thin filament connecting and even networking of the dispersed rubber phase may contribute to the overall ductility of the high impact strength of the studied blends. Moreover, its potential to induce a brittle–ductile transition of the glassy SAN matrix is considered to explain the toughening mechanism. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1685–1697, 2004
Crosslinking studies on poly(ethylene terephthalate‐co‐1,4‐phenylene bisacrylate)
Authors: Ma Hongming , Vargas Marian , Collard David M. , Kumar Satish , Schiraldi David A.
Published: December 2003

Several compositionally different poly(ethylene terephthalate‐co‐1,4‐phenylene bisacrylate) (PETPBA) copolymers were melt spun into fibers. The resulting fibers were subjected to UV irradiation to induce crosslinking. Evidence of crosslinking was obtained from FTIR, solid‐state 13C‐NMR, thermal analysis, and solubility. Irradiation of the fiber results in an increased glass‐transition temperature, reduced thermal shrinkage, and enhanced modulus retention at elevated temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1698–1702, 2004
Surface properties of miscible poly(1,1,1,3,3,3‐hexafluoroisopropyl methacrylate)/phenoxy blends
Authors: Huang H. L. , Goh S. H. , Lai Doreen M. Y. , Huan C. H. A. , Wee A. T. S.
Published: December 2003

Poly(1,1,1,3,3,3‐hexafluoroisopropyl methacrylate) (PHF) is miscible with poly(hydroxyether of bisphenol‐A) (phenoxy) as shown by the optical transparency and a single glass‐transition temperature in each blend. FTIR spectroscopy shows that the interactions between PHF and phenoxy are not particularly strong. The surface properties of the blends were studied by contact angle measurements, dynamic and static time‐of‐flight secondary ion mass spectroscopy, and X‐ray photoelectron spectroscopy. The blend surfaces were enriched with PHF. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1798–1805, 2004
Effects of convergent flow on in situ fibrillation of TLCP in PEN
Authors: Li L. , Chan C. L. , Yue C. Y. , Lam Y. C. , Tam K. C.
Published: December 2003

A polymer melt entering a capillary die from a cylinder undergoes a convergent flow in which there is a complex combination of extensional and shear flows. The convergent flow plays an important role in controlling the in situ fibrillation of thermotropic liquid crystalline polymer (TLCP) in a thermoplastic matrix melt. This study examines effects of the convergent flow on development of TLCP fibrils in a TLCP/poly(ethylene naphthalate) (PEN) blend. A capillary rheometer was used and the extent of the convergent flow was varied by changing capillary dimension and shear rate. With a given capillary die, the TLCP fibrillation was found to increase with increasing shear rate because of the increased deformation of TLCP droplets. The establishment of a fully developed shear velocity profile by using a relatively long die is considered to be necessary to retain the TLCP fibrils initiated in the convergent flow region. At a given high shear rate, TLCP fibrillation improves with increasing capillary diameter (≤2 mm) because of the increased difference in velocity between the capillary and the cylinder. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1505–1513, 2004
Compatibilization of polystyrene and polyamide 6 mixtures with poly(styrene‐co‐sodium acrylate)
Authors: Rodríguez‐Ríos H. , Nuño‐Donlucas S. M. , Puig J. E. , González‐Núñez R. , Schulz P. C.
Published: December 2003

In this work, the compatibilization of polystyrene‐and‐nylon 6 mixtures with the ionomer, poly(styrene‐co‐sodium acrylate), is investigated. The ionomer was synthesized by emulsion polymerization. Scanning electron microscopy reveals that an appreciable size reduction of the dispersed phase is achieved in the whole composition range, when small amounts of the ionomer were added. IR spectroscopy and water absorption tests disclose that a chemical reaction occurs between the carboxylic group of the ionomer and the terminal amine group of the polyamide 6, which allows the compatibilization process. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1736–1745, 2004
The effect of vibration injection molding on mechanical properties of polyolefin parts
Authors: Yan Zheng , Shen Kai Zhi , Zhang Jie
Published: December 2003

In this paper an experimental study of vibration field effect on molded polymers specimens is carried out. A self‐made vibration injection device is employed to mold the experiment samples. In the experiment some polyolefin materials are investigated, and property tests for the specimens are carried out. The results show that the tensile strength of high‐density polyethylene (HDPE) and polypropylene (PP) have an obvious increase, but polystyrene (PS) does not. The effect of vibration on the strength is related to the temperature, pressure, and gate. Lastly, the test results are analyzed and conclusions are presented. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1514–1518, 2004
Main‐chain liquid‐crystalline polymers containing azobenzene mesogen having long lateral aliphatic side chain: effect of copolymerization on thermal and phase behaviors
Authors: Sandhya K. Y. , Pillai C. K. S.
Published: December 2003

Homo‐ and copolyesters of derivatives of hydroxyazobenzenecarboxylic acid with various percentage compositions of m‐hydroxy benzoic acid (m‐HBA)/p‐hydroxy benzoic acid (p‐HBA) were synthesized and characterized. The properties of the copolyesters were compared with their corresponding homopolyesters. The solubility of the copolyesters with m‐HBA increased because of the decrease in the rigidity of the polymer chain attributed to the introduction of nonlinear molecules, whereas the solubilities of the copolyesters with p‐HBA changed only slightly compared to their corresponding homopolyesters. Thermal and phase behaviors of the polymers were characterized by TGA, DSC, and polarizing light microscopy (PLM) methods. Above 30% composition of m‐HBA, the thermal stability of the copolyesters with m‐HBA decreased compared to that of the homopolyester P1, whereas the copolyesters of p‐HBA possessed greater thermal stability than that of their homopolyesters at all compositions. The introduction of the long, flexible alkyl side chain laterally to the backbone of the azobenzene moiety drastically reduced the transition temperature of the homopolyester, but without destroying the mesophase. The effect of copolymerization on liquid‐crystalline behavior and transition temperature of the copolymers was discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1976‐1982, 2004
Preparation and properties of nylon‐1010/montmorillonite nanocomposites by melt intercalation
Authors: Liu Zengjun , Zhou Peilin , Yan Deyue
Published: December 2003

Two types of nylon‐1010/MMT nanocomposites were successfully prepared by melt intercalation using a corotating twin‐screw extruder. The nanocomposites were characterized with X‐ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis (DMA). It was found that the difference in the properties of the two types of the organo‐MMTs directly influences the structure and the properties of the obtained nanocomposites. The results of XRD and TEM showed that the DK2‐MMT nanocomposites possess an exfoliated structure and the nanocomposites containing 16C‐MMT exist as intercalated structures. The mechanical properties of the nylon‐1010/organo‐MMTs nanocomposites were better than those of the pure nynon‐1010. In addition, the properties of the DK2‐MMT nanocomposites were superior to those of the 16C‐MMT nanocomposites because of the different dispersibility of the two organo‐MMTs. The thermal stability of the nanocomposites was improved. The storage moduli of the nanocomposites increased and the glass‐transition temperature shifted to a slightly higher temperature because of the introduction of the organo‐MMTs. The addition of DK2‐MMT into the nylon‐1010 matrix accelerated the crystallization rate of the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1834‐1841, 2004
Inhibition of calcium oxalate monohydrate by poly(acrylic acid)s with different end groups
Authors: Doherty W. O. S. , Fellows C. M. , Gorjian S. , Senogles E. , Cheung W. H.
Published: December 2003

Water‐soluble low molecular weight polymers are known to affect the crystal habit of scale‐forming minerals and their rates of deposition. Poly(acrylic acid) (PAA) and poly(maleic acid) are commonly used to control scale formation in sugar mill evaporators. Calcium oxalate (both mono‐ and dihydrate) forms the bulk of the hard intractable scale found in Australian sugar mills, causing efficiency losses of significant economic importance. In this work, the formation of calcium oxalate monohydrate in a synthetic juice solution was investigated in the presence of PAAs of varying molecular weights and end‐group functionality and a strong dependency on both of these factors was observed. Terminal functionality was controlled using three chain‐transfer agents (CTA): thioethanol, thioglycolic acid, and dodecanthiol. Effectiveness of inhibition varied with CTA in the order thioethanol ∼ thioglycolic acid > dodecanthiol for all molecular weights. This suggests that polymer end groups play a role in scale inhibition. The polymers that were prepared with dodecanthiol accelerated rather than inhibited calcium oxalate formation, implying a different mode of action on calcium oxalate crystallization. Consistent with previous reports for other scales, the calcium oxalate inhibition tests show optimum effectiveness for PAAs of molecular weight 2000–4000. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2035–2041, 2004