bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrospinning of keratin/poly(ethylene oxide)blend nanofibers
Authors: Aluigi A. , Varesano A. , Montarsolo A. , Vineis C. , Ferrero F. , Mazzuchetti G. , Tonin C. 
Published: January 2007

AbstractResearch on the electrospinning of nanofibers has increased in recent years because of the number of potential applications in different areas, ranging from technical textiles (e.g., filters, composite reinforcements, and protective fabrics) to biomedical commodities and devices such as bandages, membranes, bioactive surfaces, and porous substrates for tissue engineering, for which biocompatible polymers play an essential role. In this work, wool keratin/poly(ethylene oxide) nanofibers were electrospun from aqueous solutions of polymer blends under different operating conditions. The filaments were characterized with scanning electron microscopy, Fourier transform infrared, and differential scanning calorimetry analyses and compared with films of the same materials produced via casting with the aim of investigating structural changes due to the electrospinning process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 863–870, 2007
Synthesis and properties of copolymer microemulsions of siloxane and acrylate with a high solid content
Authors: Zhang Li , Zhang Chen , Li Guoming 
Published: January 2007

AbstractCopolymer microemulsions of methyl methacrylate, butyl acrylate, and vinyltriisopropoxysilane with high monomer/surfactant ratios were prepared through a seeded semicontinuous polymerization in the presence of a redox initiator, ammonium persulfate/sodium hydrosulfate. The mean diameter of the particles decreased with an increase in the amount of the surfactant, the monomer concentration, and the vinyltriisopropoxysilane/monomer ratio, but it increased with an increase in the concentration of the initiator. When the initiator concentration was 0.23% (ammonium persulfate/sodium hydrosulfate = 1.5 : 1), the concentration of the composite surfactant was 0.9 wt %, and the reaction temperature was 50°C; the solid content of the microemulsion could be up to 43% with a small particle size (mean diameter) of 39.8 nm. The chemical, freeze–thaw, and mechanical stability of the latexes was tested as well as the thermal stability of the films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 851–857, 2007
Impact of approximating the initial bubble pressure on cell nucleation in polymeric foaming processes
Authors: Leung Siu N. , Li Hongbo , Park Chul B. 
Published: January 2007

AbstractAccording to the classical nucleation theory, the free energy barrier for bubble nucleation, and thereby the nucleation rate, are functions of the initial bubble pressure, Pbubble,0. In almost all of the previous studies that have used computer simulations to investigate polymeric foaming processes, the value of Pbubble,0 has been approximated using the saturation pressure, Psat. This article employs the thermodynamic equilibrium condition and the Sanchez–Lacombe (SL) equation of state (EOS) to determine the value of Pbubble,0. It is shown that using Psat to approximate Pbubble,0 may lead to significant overestimations of the nucleation rate and the final cell density. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 902–908, 2007
Preparation and properties of polyimides based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane
Authors: Yuan Yuan , Lin Bao‐Ping , Sun Yue‐Ming 
Published: January 2007

AbstractA series of polyimide (PI) thin films were synthesized based on bis[3,5‐dimethyl‐4‐(4‐aminophenoxy)phenyl]methane and conventional aromatic dianhydrides. The structures and properties of the thin films were measured with Fourier transform infrared, NMR, thermogravimetric analysis, dynamic mechanical analysis, and impedance analysis. The PI films exhibited glass‐transition temperatures in the range of 211–300°C and possessed initial thermal decomposition temperature reaching up to 457–482°C in air and 461–473°C in nitrogen. Some PI films had high solubility in organic solvents such as 1‐methyl‐2‐pyrrolidinone, N,N‐dimethylformamide, N,N‐dimethylacetamide, dimethyl sulfoxide, m‐cresol, tetrahydrofuran, and CHCl3. The mechanical properties of these films were also examined. The dielectric constants of the films were in the range of 2.8–3.3 at 25°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1265–1270, 2007
The effect of fabrication methods on the mechanical and thermal properties of poly(lactide‐co‐glycolide) scaffolds
Authors: Forcino Rachel G. , Jonnalagadda Sriramakamal 
Published: January 2007

AbstractThe purpose of this research was to evaluate the effects of the fabrication method, poly(ethylene glycol) (PEG) molecular weight, and PEG concentration on the mechanical and thermal properties of blended poly (lactide‐co‐glycolide) (PLGA)/PEG scaffolds. The manufacturing process was the dominant factor. The tested fabrication processes were compression, heat molding, and solvent casting/vacuum drying. The scaffolds produced by compression were strong and brittle with mechanical properties [compressive modulus (E) ∼ 400 N/mm2] comparable to those of trabecular bone. The heat‐molded scaffolds were weaker and more ductile (E ∼ 45 N/mm2) than the compressed scaffolds, so they were more applicable to non‐load‐bearing applications. The vacuum‐dried scaffolds completely lacked compressive strength (E ∼ 5 N/mm2) and were considered unsuitable for scaffolding applications. The miscibilities of the blends were also affected by the processing method and were evaluated on the basis of the melting‐point depression of crystalline PEG. The miscibility of PLGA in PEG was greatest with vacuum drying (6–13%), followed by heat molding (0.4–1.5%) and then compression (0.2–0.8%). The application of heat and solvent to the blend successfully altered the miscibility of the two polymers. Overall, this study demonstrates the ability to fabricate scaffolds with distinct thermal and mechanical characteristics by the manipulation of the fabrication method. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 944–949, 2007
Composition of the cell wall in the stem and leaf sheath of wheat straw
Authors: Yu Hui , Liu Ruigang , Qiu Limei , Huang Yong 
Published: January 2007

AbstractThe composition of the cell wall of the stem and leaf sheath of extracted wheat straw was studied with X‐ray photoelectron spectroscopy and with a field emission scanning electron microscope equipped with an energy‐dispersive microanalysis system. The outer side (epidermal side) had more lignin, and the inner side (lumen side) of the stem was rich in cellulose. The compositions of the two sides of the leaf sheath were a little different. The chemical components for the same tissue at different growth stages were essentially constant, and this indicated that cellulose, lignin, and hemicelluloses deposited in constant proportions in the cell wall of the same tissue during growth. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1236–1240, 2007
Shear and elongational rheology of polyethylenes with different molecular characteristics. II. Elongational rheology
Authors: Wei X. , Collier J. R. , Petrovan S. 
Published: January 2007

AbstractThe elongational viscosities of polyethylenes with different molecular characteristics were measured at different Hencky strains and temperatures with a capillary rheometer by the replacement of the capillary cylindrical die with a hyperbolic converging die. The hyperbolic shape of the die established a purely elongational flow field at a constant elongational strain rate throughout the die. The effects of molecular characteristics such as the molecular weight, molecular weight distribution, and long‐chain branching and processing conditions such as the temperature and Hencky strain on the elongational rheology of the polyethylene samples were studied. Good master curves were generated for temperature and Hencky strain shifting and simultaneous shifting with respect to both the temperature and Hencky strain. Both the molecular weight distribution and long‐chain branching seemed to promote strain rate thinning and reduce the elongational viscosity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1184–1194, 2007
Substitution of di(2‐ethylhexyl) phthalate by di(isononyl) cyclohexane‐1,2‐dicarboxylate as a plasticizer for industrial vinyl plastisol formulations
Authors: Crespo J. E. , Balart R. , Sanchez L. , López J. 
Published: January 2007

AbstractThe use of plasticizers with low environmental impact is one of the most interesting research fields in the plasticizer additives industry because of the possible toxicity of o‐phthalates. Among the wide variety of new plasticizers, it is important to note the use of di(isononyl) cyclohexane‐1,2‐dicarboxylate (DINCH), which shows a structure similar to the most commonly used o‐phthalates, that is, diisononyl phthalate and di(2‐ethylhexyl) phthalate (DEHP). It is necessary to evaluate the processing conditions (temperature and curing time) regarding the mechanical properties to study the possibilities for substituting conventional plasticizers and to determine whether changes in the processing conditions are needed for use in industrial applications. In this work, we carried out a comparative study of the optimum curing conditions and mechanical performance of DEHP and DINCH as plasticizers. The obtained results show that the viscosities of DINCH and DEHP‐based plastisols were similar. Furthermore, the mechanical properties of the flexible poly(vinyl chloride) obtained from DINCH‐based plastisols were very interesting for industrial applications. All of this favored the substitution of DEHP by DINCH as plasticizer for flexible poly‐ (vinyl chloride). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1215–1220, 2007
Amine‐derivatized poly(diallyldimethylammonium chloride) from N‐vinylformamide copolymerization
Authors: Tanaka Masayoshi , Tanaka Hiroo , Pelton Robert 
Published: January 2007

AbstractThe reactivity ratios for the aqueous free‐radical copolymerization of diallyldimethylammonium chloride and N‐vinylformamide were found to be 0.13 and 1.92, respectively, from a Fineman–Ross analysis of a series of batch polymerizations. Because batch polymerization could not give a uniform product in a high yield with two monomers of such different reactivities, a semibatch procedure was developed in which the more reactive N‐vinylformamide was added in 10 steps over the course of the copolymerization. The poly(diallyldimethyl‐ ammonium chloride‐co‐N‐vinylformamide) copolymers were hydrolyzed to give poly(diallyldimethylammonium chloride‐co‐vinylamine). The utility of the vinylamine/diallyldimethylammonium chloride copolymers was demonstrated by the preparation and characterization of three derivatives: (1) a copolymer with coupled dansyl groups for fluorescence detection; (2) a copolymer with coupled dabsyl groups for ultraviolet–visible detection; and (3) an ultra‐high‐molecular‐weight (1.6 × 106 Da) poly(diallyldimethylammonium chloride) by chain extension (coupling) with glycerol diglycidyl ether. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1068–1075, 2007
Effects of nanoparticles on the density reduction and cell morphology of extruded metallocene polyethylene/wood fiber nanocomposites
Authors: Guo G. , Wang K. H. , Park C. B. , Kim Y. S. , Li G. 
Published: January 2007

AbstractThis article investigates the effects of nanoparticles on cell morphology and foam expansion in the extrusion foaming of metallocene polyethylene/wood fiber nanocomposites with a chemical blowing agent. The results indicate that the addition of clay generally reduces the cell size, increases the cell density, and facilitates foam expansion. Furthermore, the foam material with added clay shows good char formation when it is burned. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1058–1063, 2007
Graft copolymerization of N‐vinyl‐2‐pyrrolidone onto sodium carboxymethylcellulose with azobisisobutyronitrile as the initiator
Authors: Yiğitoğlu Mustafa , Işıklan Nuran , Özmen Rukiye 
Published: January 2007

AbstractGraft copolymers of sodium carboxymethylcellulose with N‐vinyl‐2‐pyrrolidone were prepared in aqueous solutions with azobisisobutyronitrile as the initiator. The graft copolymers [sodium carboxymethylcellulose‐g‐poly(N‐vinyl‐2‐pyrrolidone)] were characterized with Fourier transform infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, differential scanning calorimetry, and scanning electron microscopy. The grafting parameters, including the graft yield of the graft copolymer and the grafting efficiency of the reaction, were evaluated comparatively. The effects of reaction variables such as the time, temperature, and monomer and initiator concentrations on these parameters were studied. The graft yield and grafting efficiency increased and then decreased with increasing concentrations of N‐vinyl‐2‐pyrrolidone and azobisisobutyronitrile and increasing polymerization temperatures. The optimum temperature and polymerization time were 70°C and 4.30 h, respectively. Further changes in the properties of grafted sodium carboxymethylcellulose, such as the intrinsic viscosity, were determined. The overall activation energy for the grafting was also calculated to be 10.5 kcal/mol. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 936–943, 2007
Crosslinking of reactive α‐olefins and maleic anhydride copolymers as oil sorbers
Authors: Atta Ayman M. , El‐Hamouly Sabrnal H. , Al Sabagh Ahmed M. , Gabr Moataz M. 
Published: January 2007

AbstractOctene (OC) and tetradecene (TD) monomers were copolymerized with maleic anhydride (MA) with a low conversion (<10% conversion) to determine their reactivity ratios. The monomers were copolymerized with different molar percentages of MA and OC or TD (90/10, 70/30, 50/50, and 10/90) with benzoyl peroxide as an initiator to produce MA/α‐olefin copolymers of different compositions. Fourier transform infrared was used to determine the copolymer compositions. The monomer reactivity ratios of the MA/OC and MA/TD copolymers were determined with the Fineman–Ross and Kelen–Tudos methods. Crosslinked MA/TD and MA/OC (50 : 50 mol/mol) copolymers were prepared by the condensation of the prepared linear copolymers with different glycols. The crosslinked copolymers were evaluated for oil absorbency applications. The effects of the glycol type, composition, crosslinker weight percentage, and type of oil on the swelling properties of the crosslinked polymers were studied with oil absorption tests. The swelling parameters, such as the maximum oil absorbency, characteristic oil absorbency, characteristic swelling time, and swelling rate constant, were evaluated for the synthesized sorbers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 871–881, 2007
Nonisothermal crystallization kinetics of biodegradable poly(butylene succinate)/poly(vinyl phenol) blend
Authors: Qiu Zhaobin , Yang Wantai 
Published: January 2007

AbstractNonisothermal melt crystallization kinetics of biodegradable PBSU/PVPh blend was investigated with differential scanning calorimetry (DSC) from the viewpoint of practical application. PBSU/PVPh blends were cooled from the melt at various cooling rates ranging from 2.5 to 40°C/min. The crystallization peak temperature decreased with increasing the cooling rate for both neat and blended PBSU. Furthermore, the crystallization peak temperature of PBSU in the blend was lower than that of neat PBSU at a given cooling rate. Two methods, namely the Avrami equation and the Tobin method, were used to describe the nonisothermal crystallization of PBSU/PVPh blend. It was found that the Avrami equation was more suitable to predict the nonisothermal crystallization of PBSU/PVPh blend than the Tobin method. The effects of cooling rate and blend composition on the crystallization behavior of PBSU were studied in detail. It was found that the crystallization rate decreased with decreasing the cooling rate for both neat and blended PBSU. However, the crystallization of PBSU blended with PVPh was retarded compared with that of neat PBSU at the same cooling rate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 972–978, 2007
Blend compatibility of waste materials—Cellulose acetate (from sugarcane bagasse) with polystyrene (from plastic cups): Diffusion of water, FTIR, DSC, TGA, and SEM study
Authors: Meireles Carla da Silva , Filho Guimes R. , de Assunção Rosana M. N. , Zeni Mara , Mello Kátia 
Published: January 2007

AbstractIn this article, the compatibility of blends produced from recycled materials—cellulose acetate (from sugarcane bagasse) and polystyrene (from plastic cups)—was studied using diffusion of water, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and scanning electron microscopy. With these techniques, it was possible to confirm the existence of miscibility microregions in blends produced according to what has already been pointed out in a previous paper (Filho et al., J Appl Polym Sci 2005, 96, 516). In addition, all the results present a transition occurring in blends containing 30% polystyrene. This composition indicates the starting limit for a possible inversion between the matrix and the disperse phase in the system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 909–914, 2007
Polylactide films formed by immersion precipitation: Effects of additives, nonsolvent, and temperature
Authors: Sawalha Hassan , Schroën Karin , Boom Remko 
Published: January 2007

AbstractThe influence of nonsolvent, crystallinity of the polymer film, and addition of dodecane (a poor solvent for the polymer and for the nonsolvent) on the morphology of polylactides films has been investigated and was related to phase separation behavior. Both amorphous poly‐DL‐lactide (PDLLA) and crystalline poly‐L‐lactide (PLLA) were dissolved in dichloromethane, and subsequently films were made by immersion in nonsolvent baths. PDLLA gave dense films without any internal structure, since the structure was not solidified by crystallization or glassification. PLLA films show varying structure depending on the nonsolvent. With methanol, asymmetric morphologies were observed as a result from combined liquid‐liquid demixing and crystallization, while with water symmetric spherulitic structures were formed. As a next step, dodecane was added, which is not miscible with the nonsolvent, and we found it to have a strong influence on the morphology of the films. The PDLLA films with dodecane did not collapse: a closed cell structure was obtained. In PLLA films, dodecane speeds up phase separation and induces faster crystallization in the films, and the porosity, size of the pores, and interconnectivity increased. When the PLLA solutions were subjected to a heat pretreatment, crystallization could be postponed, which yielded a cellular structure around dodecane, which did not contain spherulites anymore. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 959–971, 2007
Dispersed microfibril‐dominated deformation and fracture behaviors of linear low density polyethylene/isotactic polypropylene blends
Authors: Na Bing , Lv Ruihua , Zhao Zunxin 
Published: January 2007

AbstractLinear low density polyethylene/isotactic polypropylene (LLDPE/iPP) blends, with oriented microfibrils of iPP dispersed in the nearly isotropic LLDPE matrix, has been prepared via melt extrusion drawing and subsequent thermal treatment at 160°C to melt LLDPE matrix. The presence of oriented microfibrils of iPP in the LLDPE/iPP blends not only promotes the homogenous deformation, with no drop of nominal stress around yield point, but also enhances the fracture toughness significantly. The specific Essential Work of Fracture we, which is a pure crack resistance parameter per ligament area unit, is 24.7 and 33.6 N/mm for the blends with 15 and 30 wt % microfibrils of iPP, respectively. Moreover, with the deduced deformation parameters, such as true yield stress and strain hardening modulus, the relationship between deformation parameters and fracture toughness is explored. It is demonstrated that the fracture toughness can be well correlated with the ratio of true yield stress to strain hardening modulus σty/G, and either a decrease in yield stress or an increase in strain hardening can improve fracture toughness. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1291–1298, 2007
Preparation and characterization core‐shell particles and application for E‐Ink
Authors: Wang Jing , Feng Ya‐qing , Guo Jun‐wei , Li Yu‐kun , Li Xiang‐gao 
Published: January 2007

Abstractthe core‐shell particles were prepared by dispersion copolymerization. The core‐shell particles were characterized with Fourier‐transform infrared spectroscopy, Transmission electron microscope and scanning electron microscope. The dispersion stability and electrophoretic performance of core‐shell particles were studied in the mixed medium of tetrachloroethylene and cyclohexance. Microcapsules containing the core‐shell particles were prepared by coacervation. Results showed that the core‐shell particles had good dispersion stability and it had no electric response, which could be used as grounding particles for E‐Ink. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1195–1199, 2007
Polymerization of methyl methacrylate catalyzed by macromolecule–copper (II) complex in sodium sulfite aqueous system
Authors: Qing‐Feng Xu , Jian‐Mei Lu , Xue‐Wei Xia , Meng Xiao , Li‐Hua Wang 
Published: January 2007

AbstractVinyl polymerization initiated by a copper complex immobilized on a novel polymer and characterization has been studied. Monomer, 4‐aldehyde‐3‐hydroxy phenyl acrylate (Ahpa), and its homopolymer, poly(4‐aldehyde‐3‐hydroxy phenyl acrylate) (PAhpa), were synthesized and characterized using IR, elemental analysis,1H NMR, TOF MS, etc. The side chain of the polymer can further coordinate with transition metal ions. Its polymeric Cu(II) complex in Na2SO3system is proved to be another useful catalyst in polymerization of methyl methacrylate (MMA) at room temperature. The obtained poly(methyl methacrylate) (PMMA) is similar to those determined by conventional free radical polymerization at the same conditions. Moreover, the catalytic mechanism studied was a “Coordination Hydrogen‐Transfer” process, which is different from that of CuCl2/Na2SO3system, but analogous with that of PVAm‐Cu(II)/Na2SO3(PVAm = polyvinylamine) system, was speculated and testified. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1285–1290, 2007
Reinforcement of the interface in drawn polymer blends PS/PA‐12
Authors: Miroshnikov Y. P. , Chaves G. A. , Vlasov S. V. , Gerasimov V. I. 
Published: January 2007

AbstractThe origin of the reinforcement effect in uniaxially drawn films on the basis of immiscible blends composed of crystalline matrix of polyamide‐12 (PA) and glassy polystyrene (PS) dispersed phase has been investigated. Other conditions being equal, the effect becomes the more pronounced the lager the draw ratio and the finer the PS dispersion. Since the latter factor is itself a strong function of phase viscosity ratio (μ), the following two techniques of adjusting the optimal value of μ ≈ 1 have been adopted. According to the first one, a selective plasticizer, which is a good solvent for the PS minor phase and a nonsolvent for the PA matrix phase, was added to the more viscous PS. According to the second approach, the value of μ was varied by the use of PS samples of different molecular weights. It was shown that significant reinforcement effect appears on drawing regardless of the method of adjusting optimal phase viscosity ratio. These data as well as the results obtained with the help of IR‐dichroism and transmission electron microscopy techniques evidence that the formation of a much more ordered crystalline morphology of the PA matrix located at the PS/PA interfaces and a large interface area are mainly responsible for the discussed reinforcement phenomenon. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1299–1305, 2007