bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on viscoelasticity of polyurethane–organoclay nanocomposites
Authors: Jin J. , Song M. , Yao K. J. , Chen L 
Published: January 2006

AbstractPolyurethane (PU)/organically modified layered silicate (organoclay) nanocomposites were prepared by in situ polymerization. The viscoelasticity of PU–organoclay nanocomposites was investigated. The results suggest that the addition of organoclay resulted in the increase in the elasticity of PU and the decrease in damping property, and improvement of the thermal stability of PU significantly. However, it was also found that the addition of organoclay did not enhance the modulus of PU significantly. It was found that at high contents of soft segments, the modulus of PU decreased with the addition of organoclay. Hysteresis results indicated that energy dissipation increased with increasing organoclay. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3677–3683, 2006
Granular urea‐formaldehyde slow‐release fertilizer with superabsorbent and moisture preservation
Authors: Guo Mingyu , Liu Mingzhu , Liang Rui , Niu Aizhen 
Published: January 2006

AbstractTo improve the utilization of fertilizer and water resource at the same time, a new type of slow‐release fertilizer with superabsorbent and moisture preservation was developed, with the combination of slow‐release technique and superabsorbent polymers. The coatings were formed by the inverse phase polymerization technique. The element analysis results showed that the product contained 22.58% nitrogen element, and the water absorbency of the product was 94 times its own weight if it was allowed to swell in tap water at room temperature for 2 h. The results of the slow‐release behavior of N and the water absorbency and retention properties in soil showed that the product not only had good slow‐release property but also had excellent water absorbency and water retention capacity, which was a significant advantage over the normal slow‐release or controlled‐release fertilizers. The effects of the amount of initiator, crosslinker, reaction time, and the degree of neutralization of acrylic acid on water absorbency were investigated and optimized. At the same, a rather new and simple method was used to make homogeneous urea‐formaldehyde granules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3230–3235, 2006
Study on the spin probe added polymeric dense membranes by 13C solid‐state nuclear magnetic resonance spectroscopy
Authors: Rana D. , Matsuura T. , Khulbe K. C. , Feng C. 
Published: January 2006

AbstractDense cellulose acetate, CA, and poly(2,6‐dimethyl‐1,4‐phenylene oxide), PPO, membranes were prepared with and without blending a spin probe, TEMPO free radical, and their 13C solid‐state cross‐polarization magic angle spinning nuclear magnetic resonance, CPMAS NMR, spectra were taken. It was observed that there was no effect of blending TEMPO on the CPMAS NMR spectra of CA and PPO membranes. It was concluded that there was no chemical or physical interaction between the polymeric material and TEMPO. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3062–3069, 2006
Impact‐toughening mechanisms of calcium carbonate‐reinforced polypropylene nanocomposite
Authors: Weon J.‐I. , Gam K.‐T. , Boo W.‐J. , Sue H.‐J. , Chan C.‐M. 
Published: January 2006

AbstractThe impact fracture mechanisms of polypropylene (PP), containing 9.2 vol % of calcium carbonate (CaCO3) nanoparticles, were investigated using optical microscopy and transmission electron microscopy. The incorporation of CaCO3 nanoparticles reduces the size of spherulites and induces the formation of β‐phase crystallites, which leads to a more ductile PP matrix. Double‐notch four‐point bending (DN‐4PB) Charpy impact specimens and notched Izod impact specimens were utilized to study the fracture mechanism(s) responsible for the observed toughening effect. A detailed investigation reveals that the CaCO3 nanoparticles act as stress concentrators to initiate massive crazes, followed by shear banding in PP matrix. These toughening mechanisms are responsible for the observed, improved impact strength. A comparison of the fracture mechanisms observed between DN‐4PB Charpy and Izod impact tests is also made to show the effectiveness of DN‐4PB for investigation of impact fracture mechanisms of polymeric systems. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3070–3076, 2006
Study of creep, stress relaxation, and inverse relaxation in mulberry (Bombyx mori) and tasar (Antheraea mylitta) silk
Authors: Das Subrata , Ghosh Anindya 
Published: January 2006

AbstractThe phenomena of creep, stress relaxation, and inverse relaxation/stress recovery were observed for mulberry and tasar silk. Instantaneous extension and secondary creep are both higher for tasar than for mulberry. The magnitude of inverse relaxation increases with the increase in peak tension and reduction in retraction for both varieties of silk. The extent of inverse relaxation was found to reduce because of cycling stressing. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3077–3084, 2006
Study on the thermal degradation of polyoxymethylene by thermogravimetry–Fourier transform infrared spectroscopy (TG–FTIR)
Authors: Duan Yifei , Li Huilin , Ye Lin , Liu Xiaolong 
Published: January 2006

AbstractThermal degradation behaviors of polyoxymethylene in nitrogen are systematically studied by Thermogravimetry–Fourier Transform infrared spectroscopy (TG–FTIR). Two primary degradation mechanisms are definitely determined by the production of formaldehyde and carbon monoxide collected from successive FTIR spectrum. First, POM tends to split off formaldehyde starting at unstable chain‐ends, then random chain scission occurs at elevated temperature, and several related reactions possibly occur during the degradation process. The results prove that during the degradation, formaldehyde is the predominant product, and therefore polyether as the stabilizers used can greatly improve the degradation temperature of POM in the initial stage, and consequently effectively inhibit the thermal degradation of POM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3085–3092, 2006
Effect of carboxymethylation on the absorption and chelating properties of chitosan fibers
Authors: Qin Yimin , Hu Huiqun , Luo Aixiang , Wang Ye , Huang Xiaoyu , Song Po 
Published: January 2006

AbstractChitosan fibers were treated with chloroacetic acid to prepare partially substituted carboxymethyl chitosan fibers. Fibers with different levels of carboxymethylation were prepared by controlling the ratio between the fiber and the amount of chloroacetic acid. The absorption properties of the modified fibers for Cu(II) ions were studied at different concentrations, temperature, time, and pH. Results showed that the carboxymethylated chitosan fibers were more effective than the original chitosan fibers in removing Cu(II) ions from aqueous solutions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3110–3115, 2006
Effect of filler network on dynamic viscoelastic properties of uncured polymethylvinylsiloxanes filled with silica and carbon black
Authors: Hu Hongguo , Lin Jun , Zheng Qiang , Xu Xiaoming 
Published: January 2006

AbstractDynamic properties of polymethylvinylsiloxane (PMVS) filled with filler‐blends composed of carbon black (CB) and silica (SiO2) were investigated using an advanced rheometric expansion system. A variety of weight fraction of CB to SiO2 were 0/100, 10/90, 30/70, 50/50, 70/30, 90/10, and 100/0, and a bifunctional organsilane, bis(3‐triethoxysilylpropyl)tetrasurfane, was used to facilitate the filler dispersion. The results reveal that the incorporation of CB/SiO2 filler‐blends into PMVS result in a reduced Payne effect. This effect reaches a minimum when the ratio of CB/SiO2 approaches 1, and then it began to rebound with the ratio increase. Meanwhile, a characteristic Newtonian viscosity plateau appearing in low frequencies also significantly decreases, depending on the amount of CB or SiO2 added. On the basis of a simplified Fowke model, we ascribe this phenomenon to the deteriorated filler network, which is predominantly induced by the totally different surface activity between CB and SiO2. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3477–3482, 2006
Rubber toughening of polyamide 6/organoclay nanocomposites obtained by melt blending
Authors: Baldi F. , Bignotti F. , Tieghi G. , Riccò T. 
Published: January 2006

AbstractRubber toughening of polyamide 6 (PA6)/layered‐silicate nanocomposites was investigated. Different systems were prepared via melt blending according to different formulations. Wide‐angle X‐ray diffraction and transmission electron microscopy analyses showed that the nanocomposites had an appreciable degree of exfoliation. A linear elastic fracture mechanics approach was applied to characterize the material fracture behavior in dry conditions, whereas, because of the considerable ductility exhibited by the samples in the wet state, an elastic–plastic approach based on the essential work of fracture methodology was employed. In the absence of rubber, the presence of silicate layers makes the material fracture resistance decrease relative to neat polymer, depending on the degree of humidity. The results showed that the toughening action of rubber strongly depends on the degree of humidity of the material, at least for the rubber contents considered in this study (lower than 10 wt %). In particular, in slightly wet conditions, it was found that the addition of small amounts of rubber increased the fracture resistance of PA6/layered‐silicate nanocomposites without appreciably impairing the material stiffness. Thus, the results indicated that, for the given humidity conditions, a good balance between stiffness and toughness was obtainable by employing a suitable ratio of rubber to layered‐silicate content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3406–3416, 2006
Synthesis and characterization of oligomers containing the α‐aminoalkylphenone chromophore as oligomeric photoinitiator
Authors: Ye Guodong , Zhou Hua , Yang Jianwen , Zeng Zhaohua , Chen Yonglie 
Published: January 2006

AbstractAn oligomeric photoinitiator containing α‐aminoalkylphenone photoactive chromophore in the main chain was prepared from diphenyl ether, α‐chloroisobutyryl chloride, and piperazine through acylation, bromination, epoxidation, and polycondensation. The obtained oligomeric photoinitiator was characterized by GPC, TGA, traditional DSC, FTIR, NMR, UV–vis absorption, and fluorescence spectroscopy. The number‐average molecular weight (Mn) of the oligomeric photoinitiator was determined to be 2000–4000. The excitation and emission wavelengths of the fluorescence spectra were 376 and 473 nm, respectively. The thermal stability of the oligomer was found to be perfect with a decomposition temperature greater than 300°C. All the spectroscopic and thermal analyses clearly confirmed the consistence of property and structure. In a comparative photo‐DSC investigation, the oligomeric photoinitiator showed high photoinitiating efficiency while using 1,6‐hexanediol diacrylate as monomer. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3417–3424, 2006
Preparation and characterization of alginate–carrageenan complex films
Authors: Roh Young Hoon , Shin Chul Soo 
Published: January 2006

AbstractAlginate–carrageenan (Al–Ca) complex films were synthesized and characterized. The Al–Ca ratio and the crosslinking agent type were important factors in determining the pore size of the complex film. The pore size decreased with an increasing carrageenan content and was reduced further by a crosslinking reaction with CaCl2. The most uniform and flexibile film was formed at an Al–Ca ratio of 6:4. The degree of swelling of crosslinked films increased with an increasing carrageenan content. With a combination of CaCl2and ZnSO4, the water content of the film due to swelling was smallest, which was more suitable than with CaCl2alone. The permeabilities of glucose and dextrans for Al–Ca complex films increased as the alginate content increased, because complex films with a high alginate content had large pores. The partition coefficients of glucose and dextrans for films were in a range of 0.2 to 1.0 depending on the contents of alginate and carrageenan. A 6:4 Al–Ca complex film was most stable in a phosphate buffer solution, indicating that the 6:4 content ratio was suitable to maintain the mechanical strength of alginate–carrageenan chains. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3483–3490, 2006
Syntheses of epoxy‐bridged polyorganosiloxanes and the effects of terminated alkoxysilanes on cured thermal properties
Authors: Lee Tzong‐Ming , Ma Chen‐Chi M. , Hsu Chia‐Wen , Wu Han‐Lang 
Published: January 2006

AbstractA series of epoxy‐bridged polyorganosiloxanes have been synthesized by reacting multifunctional aminoalkoxysilanes with diglycidyl ether of bisphenol A (DGEBA) epoxy resin. The reactions of trifunctional 3‐aminopropyltriethoxysilane (APTES), difunctional 3‐aminopropylmethyldiethoxysilane (APMDS), and monofunctional 3‐aminopropyldimethylethoxysilane (APDES) with DGEBA epoxy have been monitored and characterized by FTIR, 1H NMR, and 29Si NMR spectra in this study. The synthesized epoxy‐bridged polyorganosiloxanes precursors, with different terminated alkoxysilane groups, are thermally cured with or without the addition of curing catalysts. Organometallic dibutyltindilaurate, and alkaline tetrabutylammonium hydroxide have been used as curing catalysts to investigate the thermal curing behaviors and cured properties of epoxy‐bridged polyorganosiloxanes precursors. The maximum exothermal curing temperatures of epoxy‐bridged polyorganosiloxanes precursors are found to appear around the same region of 120°C in DSC analysis. The addition of catalysts to the epoxy/APTES precursor shows significant influence on the cured structure; however, the catalysts exhibit less influence on the cured structure of epoxy‐APMDS precursor and epoxy/APDES precursor. Curing catalysts also show significant enhancement in increasing the thermal decomposition temperature (Td50s) of cured network of trifunctional epoxy‐bridged polyorganosiloxane (epoxy/APTES). High Td50s of 518.8 and 613.6 in the cured hybrids of epoxy/APTES and epoxy/APMDS precursors are also observed, respectively. When trialkoxysilane‐terminated epoxy‐bridged polyorganosiloxanes precursor are cured, with or without the addition of catalyst, no obvious Tg transition can be found in the TMA analysis of cured network. The cured network of trialkoxysilane‐terminated epoxy‐bridged polyorganosiloxanes also exhibits the lowest coefficient of thermal expansion (CTE) among the three kinds of alkoxysilane‐terminated epoxy‐bridged polyorganosiloxanes investigated. The organic–inorganic hybrid, from epoxy‐bridged polyorganosiloxanes after the thermal curing process, shows better thermal stability than the cured resin network of pure epoxy‐diaminopropane. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3491–3499, 2006
Preparation and characterization of eugenol‐grafted chitosan hydrogels and their antioxidant activities
Authors: Jung Byung‐Ok , Chung Suk‐Jin , Lee Sang Bong 
Published: January 2006

AbstractThe hydrogels composed of chitosan and eugenol were prepared to enhance and sustain antioxidant activities. The vinyl groups of eugenol monomer were directly grafted on the amino groups of chitosan, using ceric ammonium nitrate. The graft of eugenol onto chitosan was confirmed by using Fourier‐transform infrared and proton nuclear magnetic resonance spectroscopies. Results from the swelling behavior, thermal stability, and wide‐angle X‐ray diffraction revealed that the equilibrium water content decreased with increase of graft yields, because of the hydrophobicity of eugenol, although the introduction of eugenol as a side chain disturbed the ordered arrangement of chitosan's crystalline structure. The eugenol‐grafted chitosan hydrogels showed lower pH sensitivity in comparison with chitosan alone, because the amino groups, which were pH sensitive, of chitosan were grafted with eugenol. The scavenging activity of the tested hydrogels increased with graft yield of eugenol, because phenolic groups in the eugenol could play a major role as potent free‐radical terminators, in the results of improved antioxidant activity in eugenol‐grafted chitosan hydrogel in comparison with chitosan alone. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99:3500–3506, 2006
Material transport properties of polymer–gel composite‐charged mosaic membrane with and without reinforcement [II]
Authors: Hirao Kouichi , Yamauchi Akira , El Sayed A. Mounir 
Published: January 2006

AbstractThe charged mosaic membranes (CMM) without reinforcement and the composite charged mosaic membrane (CCMM) with reinforcement were investigated in terms of solute and solvent transport. The composite charged mosaic membrane (CCMM) with reinforcement showed an unique transport behavior such as preferential material transport Lp and ω. Filtration coefficient, Lp and salt permeability coefficient ω were estimated by taking account of active layer thickness of composite polymer gel. The Lp and ω values of CCMM with reinforcement were larger than those of charged mosaic membrane (CMM) without reinforcement. On the other hand, the reflection coefficient of CCMM σ showed negative value, which suggested the preferential material transport to solvent transport. This indicates that σ was independent of active layer thickness. Furthermore, the results of transport properties of CCMM with reinforcement were supported by the membrane potential measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3507–3513, 2006
Preparation and properties of a novel elastomeric polyurethane/organic montmorillonite nanocomposite
Authors: Wang Jincheng , Chen Yuehui , Wang Jialu 
Published: January 2006

AbstractA novel elastomeric polyurethane (EPU)/organic montmorillonite (OMMT) nanocomposite has been synthesized. 18 Alkane‐3 methyl‐amine chloride and dihydroxethyl‐12 alkane‐3 methyl‐amine chloride were used as intercalation agents to treat Na+‐montmorillonite and for forming two kinds of OMMTs. The better OMMT was chosen according to fourier transform infrared spectroscopy (FTIR) and wide angle X‐ray diffraction (WAXD). Three types of EPU/OMMT nanocomposites were synthesized by in situ polymerization of EPU, with different amounts of OMMT. A combination of FTIR, WAXD, and transmission electronic microscopy (TEM) studies showed that EPU/OMMT composites were on the nanometer scale and the segmented structure of EPU was hindered by the presence of the OMMT, due to the reaction between toluene diisocyanate (TDI) and the intercalation agents. Properties such as tensile property, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were researched and compared. Results showed that the EPU/3% OMMT had the best physical and mechanical properties because of its uniform dispersion of the organic silicate layers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3578–3585, 2006
A comparative study on the preparation and characterization of aromatic and aliphatic bismaleimides‐modified polyurethane–epoxy interpenetrating polymer network matrices
Authors: Mahesh K. P. O. , Alagar M. , Jothibasu S. 
Published: January 2006

AbstractInterpenetrating polymer networks of bismaleimide‐modified polyurethane–epoxy systems were prepared using the aliphatic and aromatic bismaleimides‐ and polyurethane‐modified epoxy and cured in the presence of 4,4′‐diaminodiphenylmethane. Infrared spectral analysis was used to confirm the polyurethane‐crosslinked epoxy (PU–EP). The matrices developed were characterized by mechanical, thermal, electrical, and morphological studies. The results obtained from the mechanical studies indicate that the incorporation of polyurethane and bismaleimides into epoxy increased the tensile strength, flexural strength, and impact strength, according to their nature and percentage concentration. The results obtained from the thermal and electrical studies indicate that the incorporation of polyurethane into epoxy decreased the thermal properties (glass transition temperature, heat distortion temperature (HDT), thermal stability) and electrical properties (dielectric strength, volume and surface resistivity, and arc resistance). The incorporation of aromatic bismaleimide into the polyurethane‐modified epoxy system increased the glass transition temperature, thermal stability, and electrical properties. Decreased values of glass transition and HDT were obtained in the case of aliphatic bismaleimide‐modified polyurethane–epoxy system. Surface morphology of modified epoxy systems was studied using scanning electron microscopy, and it was found that the polyurethane‐modified epoxy systems exhibited heterogeneous morphology and bismaleimides‐modified epoxy systems showed a homogeneous morphology. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3592–3602, 2006
Preparation and characteristics of Tryptophan‐imprinted Fe3O4/P(TRIM) composite microspheres with magnetic susceptibility by inverse emulsion–suspension polymerization
Authors: Lu Shulai , Cheng Guoxiang , Zhang Honggang , Pang Xingshou 
Published: January 2006

AbstractTryptophan‐imprinted Fe3O4/P(TRIM) composite microspheres with magnetic susceptibility (MS‐SMIPs) were prepared by inverse emulsion–suspension polymerization, according to the principle of molecular imprinting technique, using magnetite Fe3O4 particles as magnetically susceptible component, methacrylic acid (MAA) and acrylamide (AM) as functional monomers, trimethylolpropane trimethacrylate (TRIM) as polymeric matrix components, and hydroxy ethyl cellulose (HEC) as dispersant. The external morphology and the inner structure of MS‐SMIPs were observed by SEM. SEM photographs showed that the resulting MS‐SMIPs were regularly spherical in external morphology and had a large quantity of spherical microvoids inside. The effects of the amount of Fe3O4 on particle size and morphology of MS‐SMIPs were investigated in detail. The results indicated that the amount of Fe3O4 affected particle size distribution and morphology of MS‐SMIPs obviously. The magnetic characteristics of MS‐SMIPs were measured by vibrating sample magnetometer, and the results showed that the resulting MS‐SMIPs had a certain magnetic response to external magnetic fields. Adsorption properties, molecular recognition selectivity, and regeneration recognition selectivity of MS‐SMIPs were investigated using tyrosine and phenylalanine as control molecules, and characterized by high performance liquid chromatography. It was shown that the resulting MS‐SMIPs exhibited a good recognition selectivity for tryptophan, and the relative separation factor (β) was 2.75, and MS‐SMIPs also exhibited higher regeneration recognition selectivity, and the separation factor was 1.83 and 1.80 in first regeneration and second regeneration, respectively. The effect of the amount of functional monomers on molecular recognition selectivity was investigated, and the mechanism of imprinting and recognition was analyzed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 3241–3250, 2006