bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystallization behaviors of polypropylene/montmorillonite nanocomposites
Authors: Ma Jisheng , Zhang Shimin , Qi Zongneng , Li Ge , Hu Youliang 
Published: August 2002

AbstractThe isothermal crystallization kinetics of polypropylene/montmorillonite (PP/MMT) nanocomposites synthesized via intercalation polymerization were investigated by using differential scanning calorimeter and polarizing optical microscope (POM). The crystallinity of the nanocomposites decreased with the increase of the montmorillonite content, indicating that the MMT layers dispersed in the PP matrices confined the PP chains and hindered the crystallization of the PP chains. The POM photographs showed that the spherulites of the PP/MMT nanocomposites were greatly decreased in size as MMT was introduced. On the other hand, the crystallization rate increased dramatically with the increasing of MMT content. The interfacial free‐energy per unit area perpendicular to PP chains in PP/MMT nanocomposites decreased with increasing MMT content, suggesting that the MMT layers acted as heterogeneous nuclei in the nucleation of crystallization. The nucleus density increased with the increasing of MMT content, leading to a positive effect on the crystallization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1978–1985, 2002
Sulfonyl azides—an alternative route to polyolefin modification
Authors: Bateman Stuart A. , Wu Dong Yang 
Published: August 2002

AbstractLow‐density polyethylene was modified to incorporate aniline moieties by reactive processing with 4‐aminobenzenesulfonyl azide. Under melt‐processing conditions, the loss of nitrogen produces a sulfonyl nitrene which, in the singlet state, interacts with the substrate primarily by C–H insertion. Polymeric blends prepared from aniline‐grafted polyethylene and nylon‐66 showed improved tensile and impact properties over and above nylon blended with virgin polyethylene. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1395–1402, 2002; DOI 10.1002/app.10302
Multiwalled carbon nanotube polymer composites: Synthesis and characterization of thin films
Authors: Safadi B. , Andrews R. , Grulke E. A. 
Published: August 2002

AbstractThe aim of this article was to elucidate the basic relationships between processing conditions and the mechanical and electrical properties of multiwalled carbon nanotube reinforced polymer composites. In conventional chopped fiber reinforced polymer composites, uniform distributions of fibers throughout the matrix are critical to producing materials with superior physical properties. Previous methods have dispersed carbon nanotubes by aggressive chemical modification of the nanotubes or by the use of a surfactant prior to dispersion. 1, 2 Here, ultrasonic energy was used to uniformly disperse multiwalled nanotubes (MWNTs) in solutions and to incorporate them into composites without chemical pretreatment. Polystyrene (PS) solutions containing MWNTs were cast and spun to yield thin film MWNT composites. The rheology of PS/MWNT suspensions was modeled using the Carreau equation. MWNTs were found to align at the shear rates generated by the spin casting process. The tensile modulus and strain to failure of samples compared well to classical micromechanical models, increasing with MWNT loading. The composite films showed lower strains at the yield stress than neat PS films. The presence of MWNTs at 2.5 vol % fraction approximately doubles the tensile modulus, and transforms the film from insulating to conductive (surface resistivity, ρ, approaching 103 Ω/□). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2660–2669, 2002
Phosphorus‐containing epoxy resins: Thermal characterization
Authors: Jain Preeti , Choudhary V. , Varma I. K. 
Published: August 2002

AbstractThree novel aromatic phosphorylated diamines, i.e., bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl} pyromellitamic acid (AP), 4,4′‐oxo bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AB) and 4,4′‐hexafluoroisopropylidene‐bis N,N′‐{3‐[(3‐aminophenyl)methyl phosphinoyl] phenyl}phthalamic acid (AF) were synthesized and characterized. These amines were prepared by solution condensation reaction of bis(3‐aminophenyl)methyl phosphine oxide (BAP) with 1,2,4,5‐benzenetetracarboxylic acid anhydride (P)/3,3′,4,4′‐benzophenonetetracarboxylic acid dianhydride (B)/4,4′‐(hexafluoroisopropylidene)diphthalic acid anhydride (F), respectively. The structural characterization of amines was done by elemental analysis, DSC, TGA, 1H‐NMR, 13C‐NMR and FTIR. Amine equivalent weight was determined by the acetylation method. Curing of DGEBA in the presence of phosphorylated amines was studied by DSC and curing exotherm was in the temperature range of 195–267°C, whereas with conventional amine 4,4′‐diamino diphenyl sulphone (D) a broad exotherm in temperature range of 180–310°C was observed. Curing of DGEBA with a mixture of phosphorylated amines and D, resulted in a decrease in characteristic curing temperatures. The effect of phosphorus content on the char residue and thermal stability of epoxy resin cured isothermally in the presence of these amines was evaluated in nitrogen atmosphere. Char residue increased significantly with an increase in the phosphorus content of epoxy network. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2235–2242, 2002
Eco‐friendly durable press finishing of cellulose‐containing fabrics
Authors: Ibrahim N. A. , Abo‐Shosha M. H. , Elnagdy E. I. , Gaffar M. A. 
Published: August 2002

AbstractTo impart easy‐care properties to cellulose‐containing fabrics along with avoiding any harmful effects of formaldehyde on both the health and the environment, attempts have been made to use citric acid (CA) as an ester crosslinking agent along with different catalytic systems in the absence and presence of certain additives. Further, fixation conditions, type of crosslinking agent, as well as type of substrate have been studied. Results revealed that the enhancement in carboxyl content, performance properties, and the decrease in tear strength (TS) as well as in whiteness indices (WI) of the finished fabric samples were increased by increasing CA concentration up to 80 g/L and by raising thermofixation temperature from 140 up to 180°C for 90 s. Inclusion of triethanolamine hydrochloride (TEA. HCl), decreased the carboxyl content, TS, color strength K/S, as well as oily stain release rating (SRR) of the finished fabric samples along with an increase in bound nitrogen (%N), wrinkle recovery angle WRA, and an improvement in WI without affecting the durable press rating (DP). Within the range examined (0–30 g/L), increasing PEG‐600 concentration improved the wet resiliency, TS, as well as WI properties of the finished samples. Increasing DMDHEU ratio in the CA/DMDHEU crosslinking system gave rise to an increase in %N, WRA (dry and wet), DP, as well as in free CH2O of finished fabrics, along with a slight improvement in WI values. On the other hand, the TS, carboxyl content, K/S, SRR values of the finished fabric samples were lower at a higher DMDHEU ratio. Increase in carboxyl content, %N, WRA (dry and wet), DP and SRR, as well as extent of post dyeing (K/S) of the treated fabric samples upon using different ester crosslinking agents followed the descending order: citric acid > pyromellitic dianhydride. The opposite holds true for the TS, and WI values. Among the esterifying catalysts used, and for a given set of finishing conditions, NaH2PO2 · H2O proved to be the most effective one, and the following order of effectiveness may be drawn: NaH2PO2 · H2O > K2HPO4 > Na3–citrate > Na2–tartrate. Inclusion of silicone softener in the finishing formulation brought about an improvement in softeness degree, WRA, %N, DP, TS as well as K/S values along with a decrease in carboxyl content, SRR, and WI values of the treated fabric samples, regardless of the used silicone softener.The performance properties of the finished fabric samples were determined by the type and nature of the substrate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2243–2253, 2002
Influence of carbon fiber surface treatments on the structure and properties of conductive carbon fiber/polyethylene films
Authors: Mironov V. S. , Park Min , Choe Chulrim , Kim Junkyung , Lim Soonho , Ko Hyunhyub 
Published: August 2002

AbstractEffects of carbon fiber (CF) surface modification on the crystalline structure and both electrical and mechanical properties of conductive CF/high‐density polyethylene (HDPE) films were studied. Three different types of surface‐treated CF, epoxy‐sized, unsized, and sized but thermally treated, were considered. It was found that the uniformity of the transcrystalline zone around CF and the overall crystallinity of the polyethylene matrix decreased when epoxy‐sized CF was used. Epoxy‐sized CF caused a significant reduction not only in electrical resistivity and temperature coefficient of resistivity (TCR) but also tensile strength and coefficient of linear thermal expansion (CLTE) of composite films compared with that of unsized or sized CF that was thermally treated. We observed the systematic changes of TCR and CLTE values in accordance with CF surface modification and CF content in composite films. It was concluded that thermal expansion of the polymer matrix is the main reason for the positive TCR of CF/HDPE films. As the most probable reasons for decreased resistivity and strength of the CF/HDPE films with epoxy‐sized CF, the diffusion of epoxy sizing agent into the polyethylene matrix and the formation of loosened semiconductive interphase structure in the film are considered. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2040–2048, 2002; DOI 10.1002/app.10500
Expandable graphite systems for halogen‐free flame‐retarding of polyolefins. I. Flammability characterization and synergistic effect
Authors: Xie Rongcai , Qu Baojun 
Published: August 2002

AbstractThe use of some types of expandable graphite (EG) as an intumescent flame‐retardant additive in polyolefins was studied using the cone calorimeter test (CCT), thermogravimetric analysis (TGA), the limiting oxygen index (LOI), and the‐UL 94 test and through measurement of EG's mechanical and electrical properties. The present study has shown that some suitable EG systems combined with other organic and inorganic halogen‐free flame‐retardant (HFFR) additives apparently can improve the flame‐retardant capacity with good mechanical properties of polyolefin blends. For linear low‐density polyethylene and/or ethylene vinyl acetate/EG/HFFR blends the limiting oxygen index can reach a rating above 29, and the UL‐94 test can produce a value of V–0. The CCT and TGA data show that the EG and EG/HFFR additives not only promoted the formation of carbonaceous char but also greatly decreased the heat release rate and the effective heat of combustion and increased the residues after burning. The synergistic effect of EG with other HFFR additives, such as zinc borate, the phosphorus–nitrogen compound NP28, and microcapsulated red phosphorus is examined and discussed in detail in this article. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1181–1189, 2001
Mechanism for the plasma oxidation of wool fiber surfaces from XPS studies of self‐assembled monolayers
Authors: Dai X. J. , Elms F. M. , George G. A. 
Published: August 2002

AbstractThe O2 plasma treatment of self‐assembled monolayers (SAMs) of octadecyl mercaptan on gold substrates was investigated as a model for the oxidation of wool fiber surfaces. Three controlled low‐pressure gas‐plasma treatments were employed in which the active species were (i) atomic oxygen, (ii) atomic oxygen plus vacuum UV radiation, and (iii) full plasma treatment (charged particles in addition to the above). X‐ray photoelectron spectroscopy revealed that the plasma treatments differ from each other in the extent of oxidation and etch rate with the full plasma treatment being the most aggressive plasma. The results have confirmed that the charged particles present in a full O2 plasma treatment are responsible for rapid etching of the organic surface and thus play a significant role in the oxidation mechanism due to radical formation during this process. Vacuum UV radiation also contributes to the oxidation process. Only short plasma treatment is necessary for the oxidation of the lipid layer and the SAM is a suitable model for this process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1461–1469, 2001
Studies on high‐speed melt spinning of noncircular cross‐section fibers. III. Modeling of melt spinning process incorporating change in cross‐sectional shape
Authors: Takarada Wataru , Ito Hiroshi , Kikutani Takeshi , Okui Norimasa 
Published: August 2002

AbstractA numerical analysis program for high‐speed melt spinning of flat and hollow fibers was developed. Change in cross‐sectional shape along the spin line was incorporated adopting a formulation in which energy reduction caused by the reduction of surface area was assumed to be equal to the energy dissipation by viscous flow in the plane perpendicular to the fiber axis. In the case of flat fiber spinning, the development of temperature distribution in the cross section was considered. It was found that the empirical equations for air friction and cooling of the spin line of circular fibers can be applied for the flat fiber spin line if the geometrical mean of long‐axis and short‐axis lengths was adopted, instead of fiber diameter, as the characteristic length for Reynolds number and Nusselt number. Three features expected through the high‐speed spinning of noncircular cross‐section fibers could be reproduced: (1) although cooling of the flat fiber spin line was enhanced, calculated tension at the position of solidification was not affected much by the difference in cross‐sectional shape; (2) change in cross‐sectional shape proceeded steeply near the spinneret; and (3) temperature at the edge became significantly lower than that at the center in the cross section of flat fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1589–1600, 2001
Use of silanes and copolymers as adhesion promoters in glass fiber/polyethylene composites
Authors: Bikiaris D. , Matzinos P. , Prinos J. , Flaris V. , Larena A. , Panayiotou C. 
Published: August 2002

AbstractTwo organofunctional silanes and three functionalized copolymers were used as adhesion promoters in glass fiber/polyethylene‐reinforced composites. The performance of the coupling agents was investigated by mechanical property measurements, scanning electron microscopy, and dynamic mechanical analysis. Coupling achieved with the poly(ethylene‐g‐maleic anhydride) copolymer proved to be the most successful compared with the other copolymers (ethylene/vinyl alcohol, ethylene/acrylic acid) and silane agents (γ‐methacryloxypropyltrimethoxy, cationic styryl). The combined coupling performance of the silanes and copolymers examined in this study appears to be controlled by the coupling performance of the copolymer. Effective coupling was reflected in increased mechanical properties. Increased fiber/matrix adhesion is not always associated with effective coupling because structural changes occurring at the interface region can result in a deterioration of the material property. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2877–2888, 2001
Adsorption of heavy‐metal ions on poly(ethylene imine)‐immobilized poly(methyl methacrylate) microspheres
Authors: Duru P. Erol , Bektas Sema , Genç ömer , Pati̇r Süleyman , Denizli Adil 
Published: August 2002

AbstractPoly(methyl methacrylate) (PMMA) microspheres carrying poly(ethylene imine) (PEI) were prepared for the removal of heavy‐metal ions (copper, cadmium, and lead) from aqueous solutions with different amounts of these ions (50–600 mg/L) and different pH values (3.0–7.0). Ester groups in the PMMA structures were converted to imine groups in a reaction with PEI as a metal‐chelating ligand in the presence of NaH. The adsorption of heavy‐metal ions on the unmodified PMMA microspheres was very low [3.6 μmol/g for Cu(II), 4.6 μmol/g for Cd(II), and 4.2 μmol/g for Pb(II)]. PEI immobilization significantly increased the heavy‐metal adsorption [0.224 mmol/g for Cu(II), 0.276 mmol/g for Cd(II), and 0.126 mmol/g for Pb(II)]. The affinity order of adsorption (in moles) was Cd(II) > Cu(II) > Pb(II). The adsorption of heavy‐metal ions increased with increasing pH and reached a plateau value around pH 5.5. Their adsorption behavior was approximately described with the Langmuir equation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 197–205, 2001
Combustion characteristics of halogen‐free flame‐retarded polyethylene containing magnesium hydroxide and some synergists
Authors: Wang Zhengzhou , Qu Baojun , Fan Weicheng , Huang Ping 
Published: August 2002

AbstractHalogen‐free flame‐retarded polyethylene materials have been prepared by using magnesium hydroxide (MH) as a flame retardant combined with red phosphorous (RP) and expandable graphite (EG) as synergists. The effects of these additives on the combustion behavior of the filled linear low density polyethylene (LLDPE), such as a limiting oxygen index (LOI), the rate of heat release (RHR), the specific extinction area (SEA), etc., have been studied by the LOI determination and the cone calorimeter test. The results show that RP and EG are good synergists for improving the flame retardancy of LLDPE/MH formulations. In addition, a suitable amount of ethylene and vinyl acetate copolymer (EVA) added in the formulations can increase the LOI values while promoting the char formation and showing almost no effect on the RHR and SEA values. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 206–214, 2001
Thermal characterization of diglycidyl ether of bisphenol‐A/phosphorus containing amines
Authors: Jain Preeti , Choudhary Veena , Varma I. K. 
Published: August 2002

AbstractIn order to improve the thermal resistance of diglycidyl ether of bisphenol‐A (DGEBA), phosphorus‐containing di‐ and tri‐amines, i.e., bis (3‐aminophenyl) methyl phosphine oxide (B) and tris (3‐aminophenyl) phosphine oxide (T), were used as curing agents. The effect of phosphorus content on the curing characteristics and char residue of cured resins in nitrogen atmosphere was evaluated by using different molar ratios of conventional curing agent, i.e. 4, 4′‐diaminodiphenyl sulfone (D) and amine B or T. Activation energy of curing, as evaluated by using the multiple heating rate method, was lowest when triamine T (61.0 kJmol−1) was used as hardener and was highest when D (68.7 kJmol−1) was used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 390–395, 2001
Properties of rigid polyurethane foams blown by HCFC 141B and distilled water
Authors: Jung H. C. , Ryu S. C. , Kim W. N. , Lee Y.‐B. , Choe K. H. , Kim S.‐B. 
Published: August 2002

AbstractRigid polyurethane foams (PUFs) were prepared from polymeric 4,4′‐diphenylmethane diisocyanate, polyester polyol, 1,4‐butane diol, silicone surfactant, hydrochlorofluorocarbon (HCFC) 141B, and distilled water. The properties and structure of the PUFs were investigated with differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and a universal testing machine. The density of the PUF blown by distilled water and/or HCFC 141B decreased from 175.7 to 28.2 kg/m3 with an increase of blowing agents. From the SEM results, the average cell size of the PUF blown by distilled water increased from 150 to 290 μm with the distilled water content. From the DSC results, the glass‐transition temperature (Tg) of the PUF blown by distilled water increased from 85.7 to 101.7°C with increasing distilled water content, whereas the Tg of the PUF blown by HCFC 141B remained unchanged with HCFC 141B content. The compressive strength and modulus of the PUF blown by a mixture of distilled water and HCFC 141B was increased from 0.13 to 0.25 MPa and from 3.00 to 7.23 MPa, respectively, with the distilled water content at the sample density of about 44.0 kg/m3. The increase of the compressive strength and modulus of the PUF at the same density was related to the increase of the Tg from 86.0 to 100.9°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 486–493, 2001
Functionalization of high‐density polyethylene in the molten state by glycidyl methacrylate grafting
Authors: Torres N. , Robin J. J. , Boutevin B. 
Published: August 2002

Abstract:This study concerns the melt‐free radical grafting of glycidyl methacrylate (GMA) onto high‐density polyethylene (HDPE). We studied the effect of two initiators (tert‐butyl cumyl peroxide and di‐tert‐butyl peroxide) onto HDPE. Crosslinking of polymer was observed in the presence of 0.3 wt % tert‐butyl cumyl peroxide but not with 0.3 wt % di‐tert‐butyl peroxide. The grafting was carried out in a Brabender batch mixer at 190 °C. The grafting yield of GMA onto HDPE (determined by infrared spectrometry) is weak (<1 wt % for an initial concentration in monomer of 6 wt %). Moreover, it was noted that the degree of grafting did not vary with the concentration and the nature of peroxide used. To increase the grafting yield of GMA, we added to the HDPE/peroxide/GMA system an electron‐donating monomer, such as styrene. Adding this comonomer multiplied the rate of grafted GMA 3‐ or 4‐fold, resulting in a ratio [styrene]i/[GMA]i = 1 mol/mol with [GMA]i = 6 wt %. So, the copolymerization is favored compared with the homopolymerization. This kind of copolymer presenting reactive functions is very attractive in the field of compatibilizing immiscible polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 581–590, 2001
AB crosslinked polymers based on cationomeric polyurethane and poly(methyl methacrylate): Static and dynamic mechanical studies
Authors: Sriram V. , Aruna P. , Tharanikkarasu K. , Venkateswarlu U. , Radhakrishnan Ganga 
Published: August 2002

AbstractVinyl‐terminated polyurethane (VTPU) was prepared by end‐functionalizing isocyanate‐terminated prepolymers with 2‐bromoethanol and subsequently quartenizing with 4‐vinylpyridine. The vinyl functionality was then effectively utilized for preparing AB crosslinked polymers (ABCPs) with methyl methacrylate (MMA). ABCPs prepared with variable weight ratios on PTMG1000‐based VTPU/MMA (8/2, 6/4, 5/5, 4/6, 2/8) and those prepared at a 5/5 weight ratio with different polyols (PTMG1000, PPG1000, and PCL1250) in VTPU were characterized by Fourier transform infrared spectroscopy (FTIR) and further analyzed for thermal and mechanical properties. FTIR spectral results confirm quartenization of heterocyclic nitrogen, leading to crosslinking. Thermogravimetric analyses show enhanced thermal stability of the crosslinked systems. The stress–strain measurements reveal increasing tensile strength with increasing amounts of MMA. Comparison of dynamic mechanical spectra of ABCPs based on PTMG1000shows that the 5/5 composition exhibits good damping over a broad temperature range. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 813–821, 2001
Preliminary studies on the use of modified ALCELL lignin as a coupling agent in the biofiber composites
Authors: Rozman H. D. , Tan K. W. , Kumar R. N. , Abubakar A. 
Published: August 2002

AbstractALCELL lignin has been employed as a coupling agent in empty fruit bunch fiber (EFBF)–polypropylene (PP) composites. The lignin has been chemically modified with toluene diisocyanate (TDI) to various weight loadings. The evidence of the reaction between TDI and lignin has been observed by using Fourier transform infrared (FTIR) analysis. The effect of lignin as a coupling agent on mechanical properties has been studied. The results show that the TDI‐modified lignin is able to impart greater compatibility between EFBF and PP. This is reflected in the greater mechanical properties shown by the composites with TDI‐modified lignin than in those with the unmodified lignin. Scanning electron microscopy (SEM) studies showed that TDI modification of lignin resulted in a better blending and compatibility between lignin and PP matrix. The glass‐transition temperature of the lignin increases as the WPG is increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1333–1340, 2001