bluuebunny/crossref_metadata_2025_split huggingface dataset:
Blends of poly[3,3‐bis(chloromethyl)oxetane] with poly(vinyl acetate). I. Thermal and mechanical properties
Authors: Weilian Liu , Qipeng Guo , Zhiliu Feng 
Published: April 2003

AbstractBlends of poly[3,3‐bis(chloromethyl)oxetane] (Penton) with poly(vinyl acetate) were prepared. Compatibility, morphology, thermal behavior, and mechanical properties of blends with various compositions were studied using differential scanning calorimetry (DSC), dynamic mechanical measurements (DMA), tensile tests, and scanning electron microscopy (SEM). DMA study showed that the blends have two glass transition temperatures (Tg). The Tg of the PVAc rich phase shifts significantly to lower temperatures with increasing Penton content, suggesting that a considerable amount of Penton dissolves in the PVAc rich phase, but that the Penton rich phase contains little PVAc. The Penton/PVAc blends are partially compatible. DSC results suggest that PVAc can act as a β‐nucleator for Penton in the blend. Marked negative deviations from simple additivity were observed for the tensile strength at break over the entire composition range. The Young's modulus curve appeared to be S‐shaped, implying that the blends are heterogeneous and have a two‐phase structure. This was confirmed by SEM observations. © 1992 John Wiley & Sons, Inc.
Model for attachment of active species onto gelular polymer bead
Authors: Jo Young‐Do , Ihm Son‐Ki 
Published: April 2003

AbstractEquations for the equilibrium between the stresses and the degree of swelling, and also for the mass balance of substrate and functional groups, are proposed in order to analyze the attachment of active species onto gelular polymer bead. The asymptotic expansion technique was used to solve these equations when the relaxation rate of polymer in solvent is higher than the reaction rate and the reaction rate is much faster than the diffusion rate. It was shown that the interaction between solvent and polymer with attachment can be explained from the simulation. The equations proposed can be utilized to better understand the control of active species distributions in the polymer bead. © 1992 John Wiley & Sons, Inc.
Tris(3‐aminophenyl)Phosphine oxide‐based nadimide resins. II
Authors: Mathur Anju , Varma I. K. 
Published: April 2003

AbstractA series of phosphorus‐containing nadimide end‐capped resins having different backbones was prepared by reacting endo‐5‐norbornene‐2‐3‐dicarboxylic acid anhydride (nadic anhydride), pyromellitic dianhydride (PMDA)/3,3′,4,4′‐benzophenone tetracarboxylic acid dianhydride (BTDA)/2,2‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride (6F) and tris(3‐aminophenyl)phosphine oxide (TAP) in glacial acetic acid/acetone. Structural characterization of the resins was done by elemental analysis, FTIR, and 1H‐NMR. Thermogravimetric studies revealed a multistep decomposition reaction for uncured resins. Residual weight at 800°C in nitrogen was found to be 50–60%. Resins cured at 300°C for 1 h in air atmosphere were stable up to 440 ± 20°C and decomposed in a single step above this temperature. The char yields of cured resins were in the range 63–71.5%. © 1992 John Wiley & Sons, Inc.
Comparative rheological studies on jute‐fiber‐ and glass‐fiber‐filled polypropylene composite melts
Authors: Basu D. , Banerjee A. N. , Misra A. 
Published: April 2003

AbstractAn experimental study of the melt rheological properties of composites of isotactic poly‐propylene (IPP) filled with chopped jute‐fibers (JF) and glass‐fiber (GF) is reported. Fiber concentration is 5–20 wt %. Variation of shear stress with shear rate at constant temperature indicates increase in shear stress with shear rate and fiber loading. Shear stress values for IPP/GF melts are higher at the same shear rate and temperature. Variation of melt viscosity and melt elasticity with fiber concentration and shear stress or shear rate are also illustrated. Melt viscosity increases with fiber loading, while melt elasticity parameters such as dieswell and first normal stress difference decrease for both systems. For IPP/GF composite melts the viscosity values are higher, the die‐swell and first normal stress difference values are lower compared to IPP/JF composites melts. Processing temperature of the filled IPP composites increase with respect to the nonfilled polymer, being a little higher in case of IPP/GF composites. © 1992 John Wiley & Sons, Inc.
Bending and torsional fatigue of nylon 66 monofilaments
Authors: Toney Mary , Schwartz Peter 
Published: April 2003

AbstractUsing newly developed test equipment, the fatigue behavior of nylon 66 monofilaments was studied under two loading conditions, pure bending or simple torsion. For each mode, results are expressed in terms of the measured decay in stiffness with numbers of cycles over a range of maximum applied strain levels. Fatigue lifetimes are presented in S–N format where the log number of cycles of fatigue for a 40% decay in stiffness (N) is plotted as a function of applied strain (S). The failure mechanism for these fibers in each fatigue mode reflects the morphology of semicrystalline‐oriented synthetic fibers. In torsion, many longitudinal cracks form around the perimeter of a fiber as the result of cleavage of the relatively weak interfibrillar bonds in nylon 66. In bending, cracks form within kink band boundaries and grow at an oblique angle to the fiber axis. © 1992 John Wiley & Sons, Inc.
Interpenetrating polymer networks of polyurethane and vinyl ester resin for reactive injection molding process
Authors: Chen Ning Ping , Chen Yong Ling , Wang Dei Ning , Hu Chun Pu , Ying Sheng Kang 
Published: April 2003

AbstractThree kinds of polyurethane (PU) and vinyl ester resin interpenetrating polymer network (IPN) have been synthesized to study their morphologies and mechanical properties for the potential application in the reinforced reactive injection molding process. For the PU prepared from uretonimine modified pure MDI, the macrophase separation of the IPNs between the rubber and plastic phases was found by DSC measurement and scanning electron microscopy (SEM) observation, whereas the interpenetration between the two networks was also observed on SEM photos at least around the area of interface. However, for the IPN systems including PU prepared from TDI or graft polyol, which was synthesized by using macromer technique, the compatibility between the two phases is excellent. The mechanical properties of these IPNs were measured and could be correlated well enough with their morphologies. The IPN prepared with graft polyol exhibited the best mechanical properties over all IPN specimens studied in this work. © 1992 John Wiley & Sons, Inc.
Syntheses and electric conductivities of poly(methyl vinyl ketone‐co‐acryl amide)s reacted with phosphorus oxychloride
Authors: Kim Dae Young , Ha Chang Sik , Choi Sam Kwon , Cho Won Jei 
Published: April 2003

AbstractStudies have been made on the conductivities of poly(methyl vinyl ketone‐co‐acryl amide) [poly(MVK‐co‐AAm)]s after having reacted with phosphorus oxychloride. It was found that the conductivities were dependent on the mol ratio of [AAm] to [MVK], copolymerization temperature, and time. The effect of treatment conditions of POCl3 on the conductivities of the poly(MVK‐co‐AAm)s was shown to be significant. It was observed that the conductivities of the poly(MVK‐co‐AAm)s, treated with POCl3, are of the order of 10−6–10−9Scm−1. The maximum conductivity of the POCl3‐treated poly(MVK‐co‐AAm) was obtained as 8.7 X 10−6 Scm−1 when the mol ratio of AAm to MVK was 0.5. The conductivity of the poly(MVK‐co‐AAm) was increased with the treatment time and concentrations of POCl3. © 1992 John Wiley & Sons, Inc.
XPS studies on radiation‐induced structural changes in the copolymer of tetrafluoroethylene and ethylene
Authors: Zhong Xiaoguang , Yu Li , Sun Jiazhen , Zhang Yuefang 
Published: April 2003

AbstractIn this work, the radiation‐induced structural changes in the copolymer of tetrafluoro‐ethylene and ethylene (F‐40) were studied by X‐ray photoelectron spectroscopy (XPS). During irradiation, some CF2 groups in the polymer were found to have been converted into carbon structures that bonded indirectly with fluorine atoms. © 1993 John Wiley & Sons, Inc.
Effect of injection‐molding conditions on the crystallinity, orientation gradients, and mechanical properties of poly(aryl ether ketone). II. Large dumbbell parts
Authors: Hsiung C. M. , Cakmak M. 
Published: April 2003

AbstractHigh‐temperature thermoplastics such as poly(arylene ether ketone) form multilayer structures when they are molded at low mold temperatures. The cavity geometry, particularly the cavity thickness, plays an important role in forming these structural gradients. In this paper, we present our results on relatively thick large dumbbell specimens. Unlike the thin specimens (reported in Part I of this series of papers) that show structural gradients composed of amorphous skin‐crystalline intermediate zone and amorphous core, thicker dumbbell specimens exhibit structural gradients with increasing crystallinity from skin to core at low mold temperatures. Optical profiling on thin‐sliced specimens indicate the presence of six layers from skin to core at low mold temperatures, and the number of layers decrease with the increase of mold temperature. As the mold temperature increases, the regions near the surface increase in crystallinity while the core crystallinities remain high and unaffected by the changes in the process variables. At very high mold temperatures where thermally activated crystallization is dominant, the crystallinities become uniform throughout the thickness of the specimens. Wide‐angle X‐ray pole figure investigations indicate that the skin layers possess high preferential orientation with uniplanar axial (200) [001] texture and the core regions possessing lower orientation levels exhibit simple uniaxial texture with the chain axes oriented primarily along the flow direction. Elongation to break, tensile strength, and impact strength increase with the decrease of injection speed. The implications of these structural gradients on the mechanical properties are discussed. © 1993 John Wiley & Sons, Inc.
Young's modulus variation within polystyrene injection moldings
Authors: O'Donnell B. , White J. R. 
Published: April 2003

AbstractYoung's modulus distributions in the depth direction within injection moldings made from polystyrene have been investigated by empolying two independent techniques. Both methods show that the material close to the surface exhibits relatively high stiffness, whereas at all other depths a lower uniform stiffness exists. The depth dependency of other material characteristics, such as tan δ peaks in the dynamic mechanical thermal analysis spectra and molecular orientation, have been investigated in an attempt to correlate them with the stiffness distributions. It appears that the thermomechanical history of the different regions within the moldings, particularly the stresses acting during flow and the temperature gradients set up during cooling, are primarily responsible for the Young's modulus distributions presented here. © 1993 John Wiley & Sons, Inc.
Natural and accelerated photoaging of linear low‐density polyethylene: Changes of the elongation at break
Authors: Tidjani Adams , Arnaud René , Dasilva Anicet 
Published: April 2003

AbstractThe photoaging of different linear low‐density polyethylenes (LLDPEs), namely, ethylene–butene (EB) and ethylene–hexene (EH), has been studied. Experiments have been carried out under natural and accelerated UV exposure. We focused our investigation on the changes of elongation at break and the modifications in the chemical structure (measured by the IR technique) occurring over the photoaging process. Our results showed that the changes of elongation at break were different under the two modes of irradiation from the very beginning of UV exposure; in contrast, the comparison of stoichiometry displayed a small difference in the later stage of UV irradiation. That pointed out the difficulty of establishing a relationship between the buildup of carbonyl groups and the mechanical changes due to UV irradiation, which has been usually attempted. In addition, it appeared that the density, oxygen permeability, and the type of α‐olefin of the polymer might have an effect upon the elongation‐at‐break changes. From our data, it can be suggested that the prediction of weathering resistance of polymers can be based on both mechanical changes and modifications in chemical structure to minimize erroneous prediction. © 1993 John Wiley & Sons, Inc.
Novel low refractive index self‐cross‐linking fluoroterpolymers with very low surface tension and good adhesion to substrates
Authors: Aharoni Shaul M. , Martin Mary F. , O'Brien Kennedy P. 
Published: April 2003

AbstractA novel family of fluoroterpolymers was prepared, containing perfluoroalkylethyl methacrylate (PFAEM), methacrylic acid (MAA), and 2‐hydroxyethyl methacrylate (2‐HEM) residues. The refractive index of the fluoroterpolymers is in the range of 1.3675 ≤ n ≤ 1.4275. The surface tension of cured thin films falls in the interval from 15 mN/m to as low as 8 mN/m. Upon heating, these polymers undergo thermally initiated self‐crosslinking and develop tenacious bonding to substrates. The associated chemical reactions and products were identified by IR spectroscopy and some thermogravimetric scans. The spectra indicate that the reaction products are ester and anhydride groups. In general, the formation of esters occurs more rapidly and requires lower temperatures (≥ 110°C) than does the formation of anhydrides. Prolonged heating, especially at higher temperatures (≤ 150°C), favors the formation of anhydrides. When the molar ratio of MAA to 2‐HEM is substantially larger than 1.0, the formation of anhydride is favored; when the ratio is 1 : 1, the formation of ester is favored; and when the molar ratio is much smaller than 1.0, the rate of formation of both esters and anhydrides is greatly reduced. In the case of the fluoroterpolymers, the formed esters and anhydrides essentially originate exclusively from the MAA and 2‐HEM and seem not to involve any attack on the PFAEM residues. Only after very long heating at the higher temperatures employed, some loss of CF band intensity was noted. In a copolymer of PFAEM and MAA, a substantial and rapid attack by the acid on the ester group in the PFAEM residues takes place under relatively mild conditions. Such and more drastic conditions appear not to affect at all a homopolymer of PFAEM alone. This suggests that in the fluoroterpolymers the more polar MAA and 2‐HEM tend to aggregate close together, so that, when heated, they preferentially react with each other, forming both esters and anhydrides. In the absence of 2‐HEM, the MAA may react with itself or with PFAEM, producing only anhydride groups. Both esters and anhydrides may be intermolecular and/or intramolecular, resulting in a cross‐linked system in which the cross‐link concentration is directly related to the combined amount of ester and anhydride groups. © 1993 John Wiley & Sons, Inc.
Miscible and immiscible blends of ABS with PMMA. I. Morphology and rheology
Authors: Kim Young Jin , Shin Gui Sook , Lee In Tae , Kim Byung Kyu 
Published: April 2003

AbstractMelt blends of ABS and PMMA were prepared using three types of ABS having different acrylonitrile (AN) content, and PMMAs with different MW. From TEM micrographs, it was found that ABSs containing 24 and 27 wt % AN were miscible, and the one containing 35 wt % AN was immiscible with PMMA. Morphologically miscible blends showed welldefined semicircles in Cole—Cole plots, whereas immiscible ones showed immiscible drifts from the semicircle. In addition, as the compounding temperature increases, the dispersed PMMA phase became stratified, and more rubber particles, especially larger ones, migrated toward the PMMA phase. Miscible blends gave viscosities lower than additivity would predict, whereas immiscible ones gave positive (ABS‐rich phase) and negative (PMMA‐rich phase) deviations from the additivity. © 1993 John Wiley & Sons, Inc.
Effect of phase transitions on the volatility of UV absorbers from polypropylene
Authors: Lustoñ J. , Pastus̆áková V. , Vaśś F. 
Published: April 2003

AbstractThe volatility of 2‐hydroxy‐4‐methoxybenzophenone and 2‐(2′‐hydroxy‐5′‐methylphenyl) benzotriazole from isotactic polypropylene was studied by thermal methods in the temperature range that included the melting point of one of the stabilizers and the fusion of the polymer. The process proceeds according to the first order of kinetics. The rate constants of the stabilizers' volatility were calculated and the Arrhenius plots were constructed. The observed discontinuities in the Arrhenius dependences are interpreted as the result of the phase transitions of the polymer (melting) and the stabilizer. The activation energies for all zones were calculated. © 1993 John Wiley & Sons, Inc.
Permanently electrostatic dissipative (ESD) property via polymer blending: Rheology and ESD property of blends of PETG/ESD polymer
Authors: Lee Biing‐Lin 
Published: April 2003

AbstractRheological and electrical properties were studied on blends of a PETG polyester (cyclohexanedimethanol‐modified polyethylene terephthalate) and an inherently static dissipative high molecular weight polyether based copolymer, hereafter referred to as ESD polymer. Several important electrical properties and flow phenomena have been observed. First of all, the PETG blends could result in ESD protected material with excellent performance and a minimal effect on physical properties and melt processability. The rheological characterization reveals that the ESD polymer has a high melt viscosity even at a temperature more than 150 degrees above its melting temperature and that it exhibits pseudoplastic behavior. The PETG melt shows a near constant dynamic viscosity at a low frequency region. The viscosity of the ESD polymer and PETG melt exhibits a cross over at the temperature range from 200–220°C; the PETG melt is the lower viscosity component at low shear rate and the ESD polymer is the lower viscosity component at high shear rate. This appears to result in the existence of a small composition difference in the thickness direction of an injection‐molded ESD polymer/PETG part, with a greater fraction of the ESD polymer component in the skin section. This, in turn, could enhance the surface conductivity of the skin region of an injection‐molded part. © 1993 John Wiley & Sons, Inc.
Shear yield and crazing stresses in selected glassy polymers
Authors: Ikeda Richard M. 
Published: April 2003

AbstractThe plane strain shear yield stress and the triaxial crazing stress were determined for several commercial glassy polymers as a function of temperature. The polymers considered were: polycarbonate (Lexan®), polysulfone (Udel®), polyetherimide (Ultem®), polyarylate (Arylon®), and an amorphous nylon (Zytel® 330). When normalized to Tg the data for the various polymers were similar but not identical. An exception may be the triaxial crazing strains. In the temperature region between [T–Tg] = −300° and −50°C the crazing strains were all small (<1.5%), showed little temperature dependence, and appeared identical within the precision of our measurements. For temperatures below Tg and above any major secondary relaxation, Poisson's ratio was found to be constant for all of the polymers examined, 0.42 (±5%). © 1993 John Wiley & Sons, Inc.
Structure–property relationships of polyurethane‐based materials (PUPA) for applications in biomedicine
Authors: Cimmino S. , Martuscelli E. , Silvestre C. , Barbucci R. , Magnani A. , Tempesti F. 
Published: April 2003

AbstractPolyurethane poly(amido–amine) (PUPA) is a modified polyurethane whose chains are crosslinked with those of a tertiary aminic polymer [poly(amido–amine) (N2LL)] by the bifunctional agent hexamethylenediisocyanate (HMDI). PUPA is capable of complexing heparin; a behavior that is related to the presence of poly(amido‐amine). The effect of the chemical composition of the starting mixture and/or the reaction time on the morphology and physical properties was studied by using differential scanning calorimetry, dynamic mechanical experiments, x‐ray, scanning electron microscopy, and Fourier transform infrared attenuated total reflection analyses. © 1993 John Wiley & Sons, Inc.
Study of anionic and nonionic silicone lattices by 29Si NMR spectroscopy
Authors: Stein Judith , Leonard Tracey M. , Smith Joann F. 
Published: April 2003

AbstractThe curing of silicone lattices has been studied using 29Si NMR spectroscopy. It has been found that cross‐linking occurs prior to removal of the water. Stabilizers prevent gelation by slowing down the rate of condensation, particularly of higher functionality cross‐linkers. © 1993 John Wiley & Sons, Inc.
Surface structure and inert surface characteristics of perfluorodecanoic acid‐grafted polyurethane
Authors: Han Dong Keun , Jeong Seo Young , Kim Young Ha , Min Byoung Goo 
Published: April 2003

AbstractThe surface compositions and characteristics of perfluorodecanoic acid (PFDA)‐grafted polyurethane (PU) were investigated to understand its enhanced blood compatibility. The grafting of PFDA was identified by attenuated total reflectance–Fourier transform infrared (ATR–FTIR). The results from angular‐dependent electron spectroscopy for chemical analysis (ADESCA) demonstrated the fluorocarbon enrichment at the outermost layer in PFDA‐grafted PU. Static secondary ion mass spectroscopy (SIMS) experiments supported the results drawn from ATR–FTIR and ADESCA data about the surface compositions. Energy‐dispersive X‐ray analysis (EDXA) data by fluorine mapping also indicated a considerable coverage with fluoroalkyl groups on the PU–PFDA surface. The critical surface tension, γc, of the highly hydrophobic PU–PFDA surface revealed an extremely low value of 6.9 dyn/cm due to the optimal orientation of CF3 groups to the uppermost surface. Therefore, such an inert low‐energy surface may contribute to improve blood compatibility of PFDA‐grafted PU. © 1993 John Wiley & Sons, Inc.
The effect of radiation‐induced cross‐linking on the relaxation of taut tie molecules during annealing of drawn LDPE
Authors: Yan Rong Jiang , Luo Yunxia , Jiang Bingzheng 
Published: April 2003

AbstractShrinkage, retractive stress, and infrared dichroism of the drawn low‐density polyethylene (LDPE) as‐drawn and irradiated by 60Co‐ray have been measured under different annealing conditions. The shrinkage and the disorientation of the irradiated sample was undergone more rapidly than that of unirradiated one as the temperature was continuously increased, surpassing a certain value, and a higher degree of shrinkage and disorientation was achieved finally for the irradiated sample when the samples were annealed with free ends. For the samples heated isothermally with fixed ends, the retractive stress went through a maximum and then attenuated to a limited value, and the degree of such a stress attenuation for the unirradiated sample was much more than that for the irradiated sample. These results show that the taut tie molecules (TTMs) in drawn PE can relax by the pulling of chain segments out of crystal blocks that they anchored in at elevated temperatures higher than the α transition and also by the displacing of microfibrils if the samples were annealed with free ends. The cross‐links produced by irradiation prohibit the former process. It was further observed that the dependence of the average extinction coefficient of the band at 2016 cm−1 on that of the band at 1894 cm−1 is related to irradiation and annealing conditions, which has also been explained by the relaxation of TTMs and the function of irradiation‐induced cross‐linking on the relaxation. © 1993 John Wiley & Sons, Inc.