bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and micromechanical deformation behavior of styrene/butadiene‐block copolymers. I. Toughening mechanisms in asymmetric star block copolymers
Authors: Michler G. H. , Adhikari R. , Lebek W. , Goerlitz S. , Weidisch R. , Knoll K. 
Published: August 2002

AbstractLamellae‐forming styrene/butadiene star block copolymers are studied to investigate the influence of morphology on micromechanical deformation mechanisms and mechanical properties by using transmission electron microscopy and tensile testing. A large homogeneous plastic deformation of polystyrene (PS) lamellae is found in styrene/butadiene star block copolymers on the basis of the new mechanism called thin‐layer yielding. This mechanism depends strongly on the thickness of the PS lamellae. At a critical thickness of PS lamellae of about 20 nm, a transition from thin‐layer yielding mechanism to a crazelike deformation was observed. These new deformation zones are similar to crazes with respect to their propagation perpendicular to direction of external stress and similar to shear bands with respect to an internal shear deformation component of the lamellae in the deformation zones. As a result of our investigations, the mechanical properties of star block copolymers can be understood in correlation with morphology and micromechanical deformation mechanisms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 683–700, 2002
Thermal and mechanical properties of the polymers synthesized by the sequential polymerization of propylene and 1‐hexadecene
Authors: Jeong Han Mo , Lee Shang Hoon , Cho Kwang Jae , Jeong Young Tae , Kang Kap Ku , Oh Jae Kwon 
Published: August 2002

AbstractThe block copolymer of poly(1‐hexadecene) (PHD) and polypropylene (PP) was effectively synthesized by the sequential polymerization of propylene and 1‐hexadecene by using highly isospecific TiCl3/Cp2Ti(CH3)2 (Cp = cyclopentadienyl). The block copolymers had two separate melting temperatures of constituent blocks. The modulus of PHD–PP block copolymer was enhanced as the content of sequentially polymerized PP block was increased. The elongation at break showed positive deviation at the intermediate compositions from the simple additive values of constituent homopolymers. Shape memory effect which utilizes the crystalline PHD block as a reversible phase and the crystalline PP block as a fixed structure was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1709–1715, 2002; DOI 10.1002/app.10551
Preparation and properties of soluble copolysulfoneimide and performance of solvent‐resistant ultrafiltration membrane
Authors: Kim In‐Chul , Kim Jong‐Ho , Lee Kew‐Ho , Tae‐Moon  
Published: August 2002

AbstractSoluble copolysulfoneimides were synthesized by thermal two‐step method in solution of N‐methyl‐2‐pyrrolidone. The used aromatic diamines were bis[4‐(3‐aminophenoxy)phenyl]sulfone (BAPS‐m) and 3,3′‐diaminosulfone, and dianhydrides were pyromellitic dianhydride, 4,4′‐oxyphthalic anhydride, and 3,3′,4,4′‐diphenylsulfone tetracarboxylic dianhydride. The molar ratio of diamines was changed to reduce the content of BAPS‐m. The thermal and mechanical properties of polyimides were investigated. The polyimide ultrafiltration membrane with molecular weight cut‐off of 10 kDa could be successfully prepared by phase‐inversion method. Various solvent (water, alcohols, acetone, and hexane) fluxes were measured to investigate solvent‐resistance and membrane behavior during solvent permeation. The activation energy relationship between hexane flux and viscosity with temperature was also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1024–1030, 2002
Determination of tacticity in polypropylene by FTIR with multivariate calibration
Authors: Ozzetti Rafael A. , De Oliveira Filho Antonio Pedro , Schuchardt Ulf , Mandelli Dalmo 
Published: August 2002

AbstractA method for determination of tacticity in polypropylene (PP) using FTIR associated with multivariate analysis is presented. Blends of PP with known tacticity were prepared with isotactic, syndiotactic, and atactic polymer and analyzed by 13C‐NMR. The FTIR spectra were recorded and processed through principal components regression (PCR) and partial least‐squares regression (PLS), using information from several different portions of the spectra. The method was compared with the classical methods of tacticity determination by FTIR based on the intensities of the bands at 998 cm−1 (isotactic), 868 cm−1 (syndiotactic), and 975 cm−1 (internal standard), which are known to be dependent on the crystallinity of the polymer and, thus, affected by temperature and sample preparation. The models obtained with multivariate calibration, both with PCR and PLS, gave prediction errors up to fivefold smaller than that of the classical methods, and were also shown not to be heavily dependent on the bands that are affected by the crystallinity of the polymer, but rather on the methyl and methylene bendings at 1375 and 1462 cm−1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 734–745, 2002
Reverse atom transfer radical polymerization of stearyl methacrylate using 2,2′‐azobisisobutyronitrile as the initiator
Authors: Saikia Prakash J. , Goswami Aradhana , Baruah Shashi D. 
Published: August 2002

AbstractThe living/controlled radical polymerization of stearyl methacrylate was carried out with a conventional radical initiator (2,2′‐azobisisobutyronitrile) in N,N‐dimethylformamide in the presence of a 2,2′‐bipyridine complex of hexakis(N,N‐dimethylformamide)iron(III) perchlorate. The polymerization mechanism was thought to proceed through a reverse atom transfer radical polymerization. The molecular weights of resulting poly(stearyl methacrylate) increased with conversion, and the resulting molecular weight distributions were quite narrow. The rates of polymerization exhibited first‐order kinetics with respect to the monomer. A probable reaction mechanism for the polymerization system is postulated to explain the observed results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1236–1245, 2002
Heat treatment‐induced multiple melting behavior of carbon black‐filled polymer blends in relation to the conductive performance stabilization
Authors: Hou Yan Hui , Zhang Ming Qiu , Mai Kan Cheng , Rong Min Zhi , Yu Gang , Zeng Han Min 
Published: August 2002

AbstractPolymer blend‐based electrical conductive composites are provided with more possibilities for tailoring the performance in comparison with single polymer systems. To find an optimum heat treatment temperature of the composites, which is critical to practical applications, detailed thermal analyses of the related materials were carried out as a function of different annealing conditions. Based on the discussion of the morphological variation during treatment in terms of multiple melting behavior, it was found that an annealing temperature of 75°C is able to stabilize the resistivity of the composites within a reasonable period of time, as only solid‐state crystallization of LDPE and uniformization of EVA crystalline size are involved. In contrast to treatment at a temperature higher than 75°C, the ultimate equilibrium resistivity resulting from the above annealing procedure approaches the resistivity of the composites as‐manufactured. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1267–1273, 2001
In situ study of the dynamics of erosion of carbon black agglomerates
Authors: Seyvet Olivier , Navard Patrick 
Published: August 2002

AbstractWith the help of a counter‐rotating transparent rheometer equipped with an optical microscope, the erosion of single, commercial carbon black agglomerates suspended in a polyisobutylene fluid was accurately recorded in situ. We observed that clouds of very small aggregates were leaving the agglomerate at 45 and 225° in the shear gradient–flow direction plane, where the stress is maximum. The distribution of the arrached aggregates is more efficient when the carbon black agglomerate is more asymmetric. A spherical agglomerate of critical radius R0 will reach a radius Rt at time t following R − R = at, a being a constant. This implies that the rate at which the number of aggregates is leaving the agglomerate is a constant, independent of the size of the agglomerate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1627–1629, 2001
Recycled old newsprint fibers as a reinforcing filler in molded polyester composites
Authors: Hassan Mohammad L. , Nada Abd‐Alla M. A. 
Published: August 2002

AbstractUsing old newsprint (ONP) fibers as reinforcing filler in polyester (PE) composite has been studied. Using ONP fibers in PE composite resulted in a decrease in modulus of rupture (MOR) and an increase in modulus of elasticity (MOE) and tensile strength as compared with a neat PE composite. Also, water absorption and thickness swelling were increased as a result of using ONP fibers in the composite. Acetylation, steaming, and esterification (using maleic anhydride) of ONP fibers were performed to improve the dimensional stability of the produced composite. Acetylation and steaming of ONP fibers resulted in a decrease in the thickness swelling of the produced composites; MOR, MOE, and tensile strength were also decreased as a result of these treatments. Esterification of ONP fibers using maleic anhydride resulted in a decrease in thickness swelling of the produced composite and, at the same time, an increase in MOR, MOE, and tensile strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2018–2023, 2001
Graft copolymerization of acrylic acid onto cellulose: Effects of pretreatments and crosslinking agent
Authors: Gürdağ Gülten , Güçlü Gamze , Özgümüş Saadet 
Published: August 2002

AbstractThe graft copolymerization of acrylic acid (AA) and 2‐acrylamido 2‐methylpropane sulfonic acid (AASO3H) onto cellulose, in the presence or absence of crosslinking agent N,N′‐methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated. To investigate the effect of pretreatment of cellulose on the copolymerization, before some grafting reactions cellulose was pretreated with either 2 or 20 wt % NaOH solutions or heated in distilled water/aqueous nitric acid (2.5 × 10−3 M) at 55°C. To determine how the excess of initiator affects the grafting and homopolymerization, separate reactions were carried out by removing the excess of ceric ions by filtration of the mixture of initiator solution and cellulose before the monomer addition. Extraction‐purified products were characterized by grafting percentage and equilibrium swelling capacity. Pretreatment of cellulose with NaOH solutions decreased the grafting percentage of copolymers. In the case of AA–AASO3H mixtures, nonpretreated cellulose gave a higher grafting percentage than NaOH‐pretreated cellulose. Filtration also lowered the grafting of AA on the cellulose in the cases of pretreatment with either water or nitric acid. Copolymers with the highest grafting percentage (64.8%) and equilibrium swelling value (105 g H2O/g copolymer) were obtained in grafting reactions carried out in the presence of NMBA at 5°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2267–2272, 2001
Preparation and characterization of electroconductive polypyrrole–thermoplastic composites
Authors: Castillo‐Ortega M. M. , Encinas J.C. , Rodríguez D. E. , Olayo R. 
Published: August 2002

AbstractPolypyrrole–thermoplastic composite films were obtained by casting. Homogeneous films were prepared with dispersant poly(vinyl methyl ether) or poly(vinyl ethyl ether) by two methods. Electric conductivity, morphology, mechanical properties, and sensitivity to H2O2 in water were studied. Composites of polypyrrole with poly(vinyl chloride) carboxylated and poly(vinyl methyl ether) presented improved mechanical and electrical properties compared with other composites studied. These films were sensitive to H2O2 in water, showing a significant change in electric resistance. This change is discussed in relation to the H2O2 concentration and the exposure time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1498–1506, 2001
Effect of zone drawing on the structure and properties of melt‐spun poly(trimethylene terephthalate) fiber
Authors: Lyoo Won Seok , Lee Hyun Seok , Ji Byung Chul , Han Sung Soo , Koo Kang , Kim Sam Soo , Kim Joon Ho , Lee Joon‐Seok , Son Tae Won , Yoon Won Sik 
Published: August 2002

AbstractMelt‐spun poly(trimethylene terephthalate) (PTT) fibers were zone‐drawn and the structures and properties of the fibers were investigated in consideration of the spinning and zone‐drawing conditions. The draw ratio increased up to 4 with increasing drawing temperature to 180°C, at a maximum drawing stress of 220 MPa. Higher take‐up velocity gave lower drawability of the fiber. The PTT fiber taken up at 4000 rpm was hardly drawn, in spite of using maximum drawing stress, because a high degree of orientation had been achieved in the spinning procedure. However, an additional enhancement of birefringence was observed, indicating a further orientation of PTT molecules by zone drawing. The exotherm peak at 60°C disappeared and was shifted to a lower temperature with an increase in the take‐up velocity, which means that the orientation and crystallinity of the fiber increased. The d‐spacing of (002) plane increased with increasing take‐up velocity and draw ratio, whereas those of (010) and (001) planes decreased. In all cases, the crystal size increased with take‐up velocity and draw ratio. The cold‐drawn PTT fiber revealed a kink band structure, which disappeared as the drawing temperature was raised. The physical properties of zone‐drawn PTT fibers were improved as the draw ratio and take‐up velocity increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3471–3480, 2001
Influence of degree of crystallinity and syndiotacticity on infrared spectra of solid PVA
Authors: Sugiura Kentaroh , Hashimoto Morio , Matsuzawa Shuji , Yamaura Kazuo 
Published: August 2002

AbstractThe influence of the degree of crystallinity and the syndiotacticity on the 1145, 1095, and 916 cm−1 bands was studied. The intensity of the 1145 cm−1 band increased with increasing syndiotacticity at a low degree of crystallinity and with an increasing degree of crystallinity for a sample with syndiotacticity. The intensity of 1095 cm−1 band increased with increasing syndiotacticity at a fixed degree of crystallinity and was independent of the degree of crystallinity for a sample. The intermolecular hydrogen bonds were found to play an important role. The differences of the relations between the absorbance ratio D1145/D1095 and the degree of crystallinity with syndiotacticity were explained. The extent of the decrease of the intensity of 916 cm−1 band with an increasing degree of crystallinity increased with decreasing syndiotacticity. The predominant introduction of syndiotactic sequences in the crystals was assumed in the lower syndiotacticity. The improved equation between the syndiotactic diad content in percent [s‐(diad) %] and the absorbance ratio D916/D849 was established as s‐(diad) % = 71.1 × (D916/D849)0.327 for the films heated at 50°C with use of a syndiotactic diad content obtained from NMR spectra. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1291–1298, 2001
Biologically active polymers. IV. Synthesis and antimicrobial activity of polymers containing 8‐hydroxyquinoline moiety
Authors: Kenawy El‐Refaie 
Published: August 2002

AbstractPolymers containing 8‐hydroxyquinoline moiety were prepared. Modifications of the base polymer of glycidyl methacrylate were carried out in order to introduce chloromethyl groups, either by the hydrolysis of the poly(glycidyl methacrylate) and the chloroacetylation of the hydrolyzed polymer by the reaction with chloroacetyl chloride or by aminating the poly(glycidyl methacrylate) either with ethylenediamine or with hexamethylenediamine, followed by reacting the aminated polymers with chloroacetyl chloride. The polymers containing 8‐hydroxyquinoline moiety were prepared by reacting the chloromethyl groups containing polymers with potassium salt of 8‐hydroxy quinoline. The antimicrobial activity of the polymers obtained was examined against gram‐negative bacteria (Escherichia coli) and gram‐positive bacteria (Bacillus subtilus) as well as the fungus Trichophyton rubrum. Generally, all three polymers proved effective against the tested microorganisms, but growth inhibitory effects varied from one another. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1364–1374, 2001
Heat setting of stretched and microvoided PE/CaCO3 films
Authors: Hale W. R. , McGuire J. , Sand I. D. , Dohrer K. K. 
Published: August 2002

AbstractCalcium‐carbonate‐filled linear low‐density polyethylene (LLDPE) films play an important role in the hygienics market because these materials allow for the diffusion of water vapor (breathability) and retain a liquid barrier while providing a barrier to liquids. This is achieved when properly formulated composites are stretched to create pores. There are many important issues surrounding this technology; this report focuses on the effects of poststretching heat‐set treatment on moisture vapor transmission rate (MVTR), dynamical mechanical thermal analysis (DMTA), tensile heat distortion temperature (THDT), and differential scanning calorimetry (DSC) thermal transitions of the porous film properties. Eastman personnel provided the LLDPE/CaCO3 breathable films for this study. In general, the film properties were insensitive to heat‐setting time beyond that of 1 min. This result suggests that the molecular reorientation and recrystallization associated with the changes in film properties occur rapidly. Properties were, however, strongly sensitive to the heat‐set temperature when MVTR decreased and DMTA properties [specifically storage modulus (E′) and the α‐transition temperature] increased as the heat‐set temperature increased. This is believed to have been mainly caused by pore closure and the annealing of crystalline regions. The heat‐set temperature was easily detectable by DSC techniques when a thermal transition was apparent at the applied temperature, and changes in the heat of fusion for the sample could be observed. Ultimately, the changes in the properties of these porous films were related to changes in the molecular orientation and crystallinity of the matrix in combination with changes in the void structure of the composite. In particular, changes in E′ could be related to these separate effects. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2454–2471, 2001
Tensile elongation of high‐fluid polypropylene/ethylene–propylene rubber blends: Dependence on molecular weight of the components and propylene content of the rubber
Authors: Naiki Masahiro , Matsumura Takenobu , Matsuda Masatoshi 
Published: August 2002

AbstractWe studied tensile behavior of low‐molecular‐weight (MW) polypropylene (PP)/ethylene–propylene rubber (EPR; 70/30) blends from the viewpoint of the MWs of PP and EPR and the compatibility between PP and EPR. The value of the melt flow rate of PP varied from 30 to 700 g/10 min at 230°C. We studied the compatibility between PP and EPR by varying the propylene content in EPR (27 and 68 wt %). At the initial elongation stage, crazes were observed in all blends. When blends included EPR with 27 wt % propylene, the elongation at break of the low‐MW PP improved little. The blends with EPR and 68 wt % propylene content were elongated further beyond their yielding points. The elongation to rupture was increased with increasing MW of EPR. Molecular orientation of the low‐MW PP was manifested by IR dichroism measurements and X‐ray diffraction patterns. The blends of low‐MW PP and EPR could be elongated by the partial dissolution of EPR of high‐MW in the PP amorphous phase. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 46–56, 2002
Dynamic mechanical signatures of a polyester‐urethane and plastic‐bonded explosives based on this polymer
Authors: Hoffman D. Mark 
Published: August 2002

AbstractThe complex shear moduli of the segmented polyurethane Estane 5703p, Livermore explosive (LX)‐14, and plastic bonded explosive (PBX)‐9501, which use this polymer as a binder, have been investigated. Segmented polyurethanes, such as Estane 5703, contain microphase‐separated hard segments in a rubbery matrix of soft segments. LX‐14 is composed of 95.5% 1,3,5,7‐tetranitroazacyclooctane (HMX) explosive with 4.5% Estane 5703 binder. PBX‐9501 is composed of 94.9% HMX, 2.5% Estane 5703p binder, 2.5% nitroplasticizer (NP), and about 0.1% antioxidant Irganox 1010. In the temperature range from −150 to 120°C, two relaxations were observed as peaks in the loss modulus and tangent delta in Estane 5703p and LX‐14. A third relaxation was found in PBX‐9501. The low temperature relaxation associated with vitrification of the poly(ester urethane) soft segment occurred in the shear loss modulus (G″) at −29 and −26°C in Estane and LX‐14, respectively, at 1 Hz. In PBX‐9501 the Estane soft segment glass transition peak, Tg(SS), in the loss modulus occurred at −40 ± 3°C at 1 Hz. The reduction in soft segment glass transition in PBX‐9501 is clear evidence of plasticization of the soft segment by NP. The apparent activation energy of the maximum in the loss modulus for LX‐14 and PBX‐9501 over the frequency range from 0.1 to 10 Hz was 230 kJ/mole (55 kcal/mole). The hard segment glass transition, Tg(HS), was observed as a peak in the loss modulus at about 70°C. In LX‐14 the transition was observed at lower temperatures (56–58°C at 1 Hz) depending on thermal history. There was a low temperature shoulder on the Tg(HS) of Estane 5703 associated with soft segment crystallinity. Modulated differential scanning calorimetry (MDSC) was used to verify the Tg(HS) in Estane and 50/50 mixtures of Estane with NP. In PBX‐9501 the hard segment glass transition occurred between 65 and 72°C. The presence of NP in PBX‐9501 gave rise to a new transition, Teu(NP), between 8 and 15°C. This peak is believed to be associated with the eutectic melting of the plasticizer. Returns of fielded PBX‐9501 that were 6 and 11 years old were also measured. Small variations in Tg(SS) and the rubber plateau modulus were observed in these aged samples, consistent with migration of plasticizer and/or very low levels of chain scission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1009–1024, 2002
Polycarboxylic acids as crosslinking agents for grafting cyclodextrins onto cotton and wool fabrics: Study of the process parameters
Authors: Martel B. , Weltrowski M. , Ruffin D. , Morcellet M. 
Published: August 2002

AbstractIn this paper we describe a new method for the grafting of cyclodextrins (CDs)onto cotton or wool fabrics. The novelty principally concerns the chemical approach of the grafting reaction that was carried out in the presence of polycarboxylic acids, such as 1,2,3,4‐butanetetracarboxylic acid, citric acid, or polyacrylic acid. All types of native or CD derivatives could be used successfully as long as they carried enough remaining hydroxyl groups. For example, the amount of native β‐CD fixed onto the fabrics increased up to 12% in weight, whereas this value decreased to only 3% for the randomly methylated derivative of β‐CD (RAMEB). We observed that phosphorous salts, such as sodium mono‐ and dihydrogen phosphate or sodium dihydrogen hypophosphite, catalyzed the reaction. On the other hand, the conventional and convenient pad–dry–cure technique that is currently used at the industrial scale in textile processing was applied. We report that the polycarboxylic acids play the role of linking agent through an esterification (or amidification) reaction with the OH (or NH2) groups of both CD and cotton (or wool) fibers. In addition, this reaction could lead to the graft of a copolymer formed between CD and the polycarboxylic acid. The reaction yield depends on the concentration and nature of the aforementioned reactants and catalysts and on the curing conditions (time and temperature). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1449–1456, 2002