bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and properties of multihydroxy soybean oil from soybean oil and polymeric methylene‐diphenyl‐ 4,4′‐diisocyanate/multihydroxy soybean oil polyurethane adhesive to wood
Authors: Choi Seung Woo , Wan Seo Dong , Don Lim Young , Gi Jeong Young , Islam Mollah M. S. , Park Heon , Whan Hong Tae , Gi Kim Whan 
Published: February 2011

AbstractThe reactive multihydroxy soybean oil (MHSBO) was synthesized from epoxidized soybean oil (ESBO). The ESBO was reacted with ethylene glycol to obtain MHSBO having high functionality. This study investigated a feasibility to prepare wood adhesive through the reaction of polymeric methylene‐diphenyl‐4,4′‐diisocyanate (pMDI) with MHSBO. Different polyurethane adhesives were prepared with a variety of equivalent mole ratios (eq. mole ratios) of MHSBO to pMDI. The chemical reactions of adhesives were analyzed using 1H NMR and Fourier transform infrared (FTIR), and their thermal studies were investigated by DSC and TGA. The MHSBO/pMDI resins (3 : 1 and 2 : 1 eq. mole ratios) showed endothermic peaks, whereas the MHSBO/pMDI resins (1 : 2 and 1 : 3 eq. mole ratios) showed exothermic peaks. The best adhesion strength was found when plywood was bonded with the adhesive of a eq. mole ratio of 2 : 1 (MHSBO : pMDI). These results indicated that the bond strength was not related to the reactivity obtained from the FTIR spectra. But it was explained that the adhesion strength increased as the residual NCO groups in the adhesive reacted with the hydroxy groups of wood during the manufacturing of plywood. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of hydrogel‐silver nanoparticle‐curcumin composites for wound dressing and antibacterial application
Authors: Varaprasad K. , Mohan Y. Murali , Vimala K. , Mohana Raju K. 
Published: February 2011

AbstractHydrogel silver nanocomposites are found to be excellent materials for antibacterial applications. To enhance their applicability novel hydrogel‐silver nanoparticle‐curcumin composites have been developed. For developing, these composites, the hydrogel matrices are synthesized first by polymerizing acrylamide in the presence of poly(vinyl sulfonic acid sodium salt) and a trifunctional crosslinker (2,4,6‐triallyloxy 1,3,5‐triazine, TA) using redox initiating system (ammonium persulphate/TMEDA). Silver nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating the silver ions and subsequent reduction with sodium borohydride. Curcumin loading into hydrogel‐silver nanoparticles composite is achieved by diffusion mechanism. A series of hydrogel‐silver nanoparticle‐curcumin composites are developed and are characterized by using Fourier transform infrared (FTIR) and UV–visible (UV–vis) spectroscopy, X‐ray diffraction, thermal analyses, as well as scanning and transmission electron microscopic (SEM/TEM) methods. An interesting arrangement of silver nanoparticles i.e., a shining sun shape (ball) (∼ 5 nm) with apparent smaller grown nanoparticles (∼ 1 nm) is observed by TEM. The curcumin loading and release characteristics are performed for various hydrogel composite systems. A comparative antimicrobial study is performed for hydrogel‐silver nanocomposites and hydrogel‐silver nanoparticle‐curcumin composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermal, kinetic, and mechanical properties of glycerol‐plasticized wheat gluten
Authors: Pan Yongkang , Wang Xuehong , Yuan Qiaolong 
Published: February 2011

AbstractGlycerol‐plasticized wheat gluten was prepared by mixing in an internal mixer equipped with sigma rotors, and then thermally compression‐molded to form a sheet for crosslinking and tensile tests. Referring to rubber vulcanization process, rotorless curemeter was applied to test the vulcanization characteristic parameters of the molded round samples, which could be used to calculate the activation energy and reaction rate of crosslinking occurring in wheat gluten when heated. Vulcanizing curves obtained show that the optimum temperature for processing glycerol‐plasticized wheat gluten is 150°C, and that activation energy and reaction rate of crosslinking in wheat gluten plasticized with 20 wt % glycerol reach minimum and maximum values, respectively. In addition, glycerol content, plasticizing time, and temperature have significant effects on the mechanical properties of thermomolded wheat gluten plastics. The factors are closely related to the establishment of a covalent network resulting from the formation and rearrangement of disulfide bridges in wheat gluten. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermoplastic natural rubber based on polyamide‐12: Influence of blending technique and type of rubber on temperature scanning stress relaxation and other related properties
Authors: Narathichat M. , Kummerlöwe C. , Vennemann N. , Nakason C. 
Published: February 2011

AbstractThermoplastic natural rubber based on polyamide‐12 (PA‐12) blend was prepared by melt blending technique. Influence of blending techniques (i.e., simple blend and dynamic vulcanization) and types of natural rubber (i.e., unmodified natural rubber (NR) and epoxidized natural rubber (ENR)) on properties of the blends were investigated. It was found that the simple blends with the proportion of rubber ∼ 60 wt % exhibited cocontinuous phase structure while the dynamically cured blends showed dispersed morphology. Furthermore, the blend of ENR exhibited superior mechanical properties, stress relaxation behavior, and fine grain morphology than those of the blend of the unmodified NR. This is attributed to chemical interaction between oxirane groups in ENR molecules and polar functional groups in PA‐12 molecules which caused higher interfacial adhesion. It was also found that the dynamic vulcanization caused enhancement of strength and hardness properties. Temperature scanning stress relaxation measurement revealed improvement of stress relaxation properties and thermal resistance of the dynamically cured ENR/PA‐12 blend. This is attributed to synergistic effects of dynamic vulcanization of ENR and chemical reaction of the ENR and PA‐12 molecules. Furthermore, the dynamically cured ENR/PA‐12 blend exhibited smaller rubber particles dispersed in the PA‐12 matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Migration of novel epoxidized neem oil as plasticizer from PVC: Experimental design approach
Authors: Gamage Padmasiri K. , Farid Ahmed S. 
Published: February 2011

AbstractMigration behavior of epoxidized neem oil (ENO) from poly(vinyl chloride) (PVC) plasticized with ENO to acrylo nitrile butadiene rubber (NBR) was investigated. Central composite rotatable design (CCRD) for three variables at five levels was chosen as the experimental design. Concentration of Neem oil in PVC matrix, acrylo nitrile (ACN%) content in NBR matrix, and peroxide content used in NBR formulation were selected as three independent variables. Other parameters pertinent to migration phenomena such as partition coefficient, activation energies, rate constants, and diffusion coefficients were evaluated and these properties were fitted to a distinctive response equation generated by CCRD. Proposed response equations for most parameters were considered as having sufficient explanatory power and “good fit” in the statistical sense. Partitioning of ENO as a plasticizer between PVC and NBR follows first order equilibrium kinetics, and the forward reaction is found to be endothermic. The percentage migration of plasticizer at 296 K at equilibrium is well below 25% for the majority of cases irrespective of other pertinent factors. Parameters such as forward, backward, and overall rate constants and their respective activation energies and enthalpy change related to the partitioning phenomenon are influenced to different degrees by plasticizer concentration in PVC, ACN% in NBR and crosslink density of NBR. The influence caused by plasticizer concentration and ACN% was found to be the most significant. Diffusion of plasticizer through PVC matrix is the rate determining step for the overall migration process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology of silver particulate films deposited on softened polymer blends of polystyrene and poly (4‐vinylpyridine)
Authors: Parashar Pratima 
Published: February 2011

AbstractResults of the morphological studies of silver particulate films deposited at a rate of 0.4 nm/s on polymeric blends of polystyrene (PS) and poly (4‐vinylpyridine) (P4VP) held at a temperature 457 K by evaporation in a vacuum of 8 × 10−6 Torr are reported here. The morphology of silver particulate films was characterized by their size, size distribution, shape and interparticle separation. It has been observed that morphology depends on the composition of polymer matrix and the amount of silver deposited. The red shift in the plasmon resonance was observed with the increasing amount of P4VP in the blends in comparison to the pure PS. This indicates the modification in the silver particulate films deposited on the PS/P4VP blends. Scanning electron microscopy (SEM) was used to study the change in morphology of the silver nanoparticles and was correlated with the optical properties of silver particulate films on PS/P4VP blends. The silver nanoparticles deposited on the thin layers of polymer blends exhibit smaller size with narrower dispersion and wider size distribution due to blending of P4VP with PS. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of polypropylene/serpentine composites
Authors: Tan Semra , Tincer Teoman 
Published: February 2011

AbstractComposites of serpentine and polypropylene (PP) were prepared by twin‐screw extrusion. Serpentine was collected as rocks from the Ankara–Beynam region and ground into powder with an average particle size of about 3 μm for composite production. Both as‐received (rock) and powdered serpentine were characterized. A silane coupling agent (SCA), γ‐aminopropyl triethoxy silane, was used for the surface treatment of serpentine. Mechanical properties of the composites were measured in terms of impact strength, elastic modulus, stress at yield, stress at break, and percentage strain at break. The addition of serpentine was found to have a profound effect on the reinforcement of the PP matrix. Because of the stronger interactions at the interphase induced by SCA treatment, mechanical properties were improved further in comparison with the untreated composites. Similar thermal and morphological behaviors were recorded for the composites with and without surface treatment. Thermal studies showed an increase in both melting temperature and percentage crystallinity of the composites. Scanning electron microscopy analysis revealed that homogeneous distribution of filler was observed at low filler contents, but a certain extent of agglomeration was also seen at high filler loadings. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Capacitance properties of graphite oxide/poly(3,4‐ethylene dioxythiophene) composites
Authors: Han Yongqin , Ding Bing , Tong Hao , Zhang Xiaogang 
Published: February 2011

AbstractPoly(3,4‐ethylene dioxythiophene) (PEDOT) and graphite oxide (GO)/PEDOT composites (GPTs) doped with poly(sodium styrene sulfate) (PSS) were synthesized by in situ polymerization in aqueous media. The electrochemical capacitance performances of GO, PEDOT–PSS, and GPTs as electrode materials were investigated. The GPTs had a higher specific capacitance of 108 F/g than either composite constituent (11 F/g for GO and 87 F/g for PEDOT–PSS); this was attributable to its high electrical conductivity and the layer‐within/on‐layer composite structure. Such an increase demonstrated that the synergistic combination of GO and PEDOT–PSS had advantages over the sum of the individual components. On the basis of cycle‐life tests, the capacitance retention of about 78% for the GPTs compared with that of 66% for PEDOT–PSS after 1200 cycles suggested a high cycle stability of the GPTs and its potential as an electrode material for supercapacitor applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical properties, morphology, and crystal structure of polypropylene/chemically modified attapulgite nanocomposites
Authors: Chen Jianjun , Chen Jinyao , Zhu Shipeng , Cao Ya , Li Huilin 
Published: February 2011

AbstractAtactic polypropylene (aPP) was chemically grafted onto attapulgite (ATP) via the bridge linking of a polymerizable cationic surfactant and poly(octadecyl acrylate) in the presence of ultrasonic oscillation and dicumyl peroxide, and then, the modified ATP was added to a polypropylene (PP) matrix to obtain PP nanocomposites by melt blending. The results of Fourier transform infrared spectroscopy and X‐ray photoelectron spectroscopy confirmed that aPP and poly(octadecyl acrylate) were chemically grafted onto ATP through a graft polymerization reaction. The results of the mechanical properties testing showed that the addition of modified ATP improved the toughness and strength of PP remarkably. The dynamic mechanical analysis indicated that the modified ATP significantly increased the storage modulus and decreased the glass‐transition temperature of PP. The results of scanning electron microscopy and transmission electron microscopy showed that the modified ATP was uniformly dispersed into the PP matrix as crystal needles; this proved the presence of strong interactions between modified ATP and PP. The crystal structure analysis revealed that the β‐form crystalline of PP was formed within the modified ATP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Adhesion of polyethylene plates photografted with methacrylic acid and acrylic acid with enzymatically modified chitosan solutions and X‐ray photoelectron spectroscopy analysis of failed surfaces
Authors: Yamagami Sho , Kanama Wataru , Yamada Kazunori 
Published: February 2011

AbstractAn investigation was carried out on the application of dilute chitosan solutions modified by a tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenetylamine (dopamine) to the adhesion of low‐density polyethylene (LDPE) and high‐density polyethylene (HDPE) plates photografted with carboxyl‐group‐containing hydrophilic monomers, such as methacrylic acid (MAA) and acrylic acid (AA). In the case where photografting was carried out at lower monomer concentrations or at lower temperatures, the adhesive strength sharply increased with lower grafted amounts. A sharp increase in the adhesive strength was found to be due to the formation of shorter grafted polymer chains at lower monomer concentrations and/or the restriction of the location of grafting to the outer surface region at lower temperatures. In addition, the adhesive strength also sharply increased at even lower grafted amounts for photografting onto the HDPE plates and/or that of AA because the location of grafting was restricted to the outer surface region. For the AA‐grafted LDPE and HDPE plates, substrate breaking was observed. This was attributed to the coverage of the substrate surfaces with grafted poly(acrylic acid) chains at lower grafted amounts and a high water absorptivity of the grafted layer. X‐ray photoelectron spectroscopy (XPS) analysis of the grafted LDPE plates incubated in a dopamine solution containing tyrosinase suggested that the increase in the adhesive strength was caused by the penetration of enzymatically modified chitosan solutions in the grafted layers and the subsequent reaction of quinone derivatives enzymatically generated with grafted polymer chains. In addition, the surface analysis of the failed surfaces by XPS showed that as the adhesive strength increased, the location of failure was shifted from the interface between the layers mixed with enzymatically modified chitosan materials and grafted polymer chains to the inside the grafted layer containing enzymatically modified chitosan materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Nanoindentation of isotactic polypropylene: Correlations between hardness, yield stress, and modulus on the local and global scales
Authors: Lesan‐Khosh R. , Bagheri R. , Asgari S. 
Published: February 2011

AbstractThe correlations between the hardness, yield stress, and modulus of elasticity of isotactic polypropylene (iPP) were evaluated on the local and global scales. Nanoindentation and traditional macromechanical tests were incorporated for this purpose. Thus, local and global mechanical properties were measured at various temperatures and strain rates. A certain relation was found between the local and global mechanical properties. Moreover, Johnson's model (developed according to the expanding cavity model) was also evaluated at various temperatures and strain rates. The Johnson model was valid only for the yield stresses obtained by nanoindentation and compressive tests and also the elastic modulus obtained via nanoindentation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
New hyperbranched polymers for membranes of high‐temperature polymer electrolyte membrane fuel cells: Determination of the crystal structure and free‐volume size
Authors: Bhadra Sambhu , Ranganathaiah C. , Kim Nam Hoon , Kim Seong‐Il , Lee Joong Hee 
Published: February 2011

AbstractThe key requirements for a membrane in polymer electrolyte membrane fuel cells are a high ion conductivity, mechanical strength, and barrier properties. We reported earlier on two new promising hyperbranched polymers: poly(benzimidazole‐co‐aniline) (PBIANI), with a uniform rectangular net structure, and poly(benzimidazole‐co‐benzene) (PBIB), with a honeycomb structure. Both polymers exhibit a high ion conductivity and mechanical strength and have proven themselves suitable for the membranes of high‐temperature polymer electrolyte membrane fuel cells. In this article, we deal with the determination of crystal structure and free‐volume cell/microvoid size of these two polymers. Both PBIANI and PBIB had the same d‐spacing (3.5 Å). However, the percentage of crystallinity was higher and the crystallite size was larger for PBIB. The kinetic diameters of hydrogen (2.89 Å), oxygen (3.46 Å), water (2.60 Å), and methanol (∼ 4.00 Å) were much larger than the free‐volume cell/microvoid diameters of PBIANI (1.81 Å) and PBIB (1.96 Å) but much smaller than those of Nafion 115 (6.54 Å) and polybenzimidazole (PBI) (∼ 6.00 Å). The very small free‐volume sizes of PBIANI and PBIB ensured good barrier properties against hydrogen, oxygen, water, and methanol, unlike those of Nafion‐ and PBI‐type membranes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Hemp‐fiber‐reinforced unsaturated polyester composites: Optimization of processing and improvement of interfacial adhesion
Authors: Qiu R. , Ren X. , Fifield L. S. , Simmons K. L. , Li K. 
Published: February 2011

AbstractThe processing variables for making hemp‐fiber‐reinforced unsaturated polyester (UPE) composites were optimized through orthogonal experiments. It was found that the usage of initiator, methyl ethyl ketone peroxide, had the most significant effect on the tensile strength of the composites. The treatment of hemp fibers with a combination of 1,6‐diisocyanatohexane (DIH) and 2‐hydroxyethyl acrylate (HEA) significantly increased tensile strength, flexural modulus of rupture, and flexural modulus of elasticity, and water resistance of the resulting hemp‐UPE composites. FTIR spectra revealed that DIH and HEA were covalently bonded to hemp fibers. Scanning electron microscopy graphs of the fractured hemp‐UPE composites demonstrated that treatment of hemp fibers with a combination of DIH and HEA greatly improved the interfacial adhesion between hemp fibers and UPE. The mechanism of improving the interfacial adhesion is proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fabrication of poly(lactic acid) films with resveratrol and the diffusion of resveratrol into ethanol
Authors: Soto‐Valdez Herlinda , Auras Rafael , Peralta Elizabeth 
Published: February 2011

AbstractPoly(94% L‐lactic acid) (PLA) films containing 0, 1, and 3 wt % resveratrol (PR0, PR1, and PR3) were extruded in a pilot‐plant scale blown‐extrusion machine. Yellow‐colored PLA films with reduced crystallinity were obtained, and the films absorbed UV‐visible light at 350–200 nm. The diffusion kinetics of resveratrol into ethanol at 9, 23, 33, and 43°C displayed Fick's behavior, and diffusion coefficients between 10−13 and 10−10 cm2/s were obtained. According to the Arrhenius equation, the energy of activation for the diffusion of resveratrol from PR1 and PR3 films was 175 and 177 kJ/mol, respectively. The temperature of diffusion had a stronger effect on the reduction of the weight average molecular weight of PLA than the processing conditions and the contact time with ethanol. However, diffusion of resveratrol was not affected by the degradation of PLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of crosslinked polymer beads with tunable pore morphology
Authors: Liu Qingquan , Li Yanlu , Shen Shaohua , Xiao Qiuguo , Chen Lijuan , Liao Bo , Ou Baoli , Ding Yue 
Published: February 2011

AbstractCrosslinked polymer beads with tunable pore morphology were prepared by suspension polymerization of styrene (St) and divinylbenzene (DVB) with polypropylene in combination with toluene as co‐porogens. The effect of DVB content on the pore morphology was investigated by changing DVB amount in monomer mixture. The results indicated that the specific surface area, the total pore area, and the total pore volume increased with increasing DVB content of polymer beads. Moreover, high‐DVB concentration was favorable to produce more micropores and mesopores. At a given DVB concentration, the volume ratio of co‐porogen/DVB has significant impact on the pore morphology in crosslinked polymer beads. As the co‐porogen amount was increased, the specific surface area, the total pore area, and the total pore volume were dramatically increased, furthermore, the pore size distribution derived from Hg intrusion shifted toward macropore. Overall, the present article provided a novel route to prepare crosslinked polymer beads with tunable pore morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Structure and properties of PP/POE/HDPE blends
Authors: Chen Yanhua , Ye Lin 
Published: February 2011

AbstractThis work was aimed to counteract the effect of ethylene‐α‐olefin copolymers (POE) by reinforcing the polypropylene (PP)/POE blends with high density polyethylene (HDPE) particles and, thus, achieved a balance between toughness and strength for the PP/POE/HDPE blends. The results showed that addition of HDPE resulted in an increasing wide stress plateau and more ductile fracture behavior. With the increase of HDPE content, the elongation at break of the blends increased rapidly without obvious decrease of yield strength and Young's modulus, and the notched izod impact strength of the blends can reach as high as 63 kJ/m2 at 20 wt % HDPE loading. The storage modulus of PP blends increased and the glass transition temperature of each component of the blends shifted close to each other when HDPE was added. The crystallization of HDPE phase led to an increase of the total crystallinity of the blend. With increasing HDPE content, the dispersed POE particle size was obviously decreased, and the interparticle distance was effectively reduced and the blend rearranged into much more and obvious core‐shell structure. The fracture surface also changed from irregular striation to the regularly distant striations, displaying much obvious character of tough fracture. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011