bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymer Therapeutics: Concepts and Applications
Authors: Haag Rainer , Kratz Felix
Published: January 2006

Polymer therapeutics encompass polymer–protein conjugates, drug–polymer conjugates, and supramolecular drug‐delivery systems. Numerous polymer–protein conjugates with improved stability and pharmacokinetic properties have been developed, for example, by anchoring enzymes or biologically relevant proteins to polyethylene glycol components (PEGylation). Several polymer–protein conjugates have received market approval, for example the PEGylated form of adenosine deaminase. Coupling low‐molecular‐weight anticancer drugs to high‐molecular‐weight polymers through a cleavable linker is an effective method for improving the therapeutic index of clinically established agents, and the first candidates have been evaluated in clinical trials, including, N‐(2‐hydroxypropyl)methacrylamide conjugates of doxorubicin, camptothecin, paclitaxel, and platinum(II) complexes. Another class of polymer therapeutics are drug‐delivery systems based on well‐defined multivalent and dendritic polymers. These include polyanionic polymers for the inhibition of virus attachment, polycationic complexes with DNA or RNA (polyplexes), and dendritic core–shell architectures for the encapsulation of drugs. In this Review an overview of polymer therapeutics is presented with a focus on concepts and examples that characterize the salient features of the drug‐delivery systems.
Amino Acid Derived Macrocycles—An Area Driven by Synthesis or Application?
Authors: Gibson Susan E. , Lecci Cristina
Published: January 2006

The synthesis, structure, and physical properties of macrocycles have fascinated chemists for many years. Their inherent properties make them useful in areas as diverse as ion transport across membranes, development of new antibiotics, and catalysis. In this Review, the authors examine the chemistry of macrocycles containing non‐peptidic amino acid derived molecules; the analysis is discussed in terms of function, rather than structure or synthesis. It is revealed that the diverse and imaginative structures created by synthetic chemists are not being fully exploited in application‐driven endeavors.
A mild and efficient palladium–triethylsilane system for reduction of olefins and carbon–carbon double bond isomerization
Authors: Mirza‐Aghayan Maryam , Boukherroub Rabah , Bolourtchian Mohammad
Published: January 2006

The versatility of palladium(II) acetate and palladium on activated charcoal catalysts with triethylsilane has been investigated in the hydrogenation and the isomerization of carbon–carbon double bond of 1‐alkenes. The reduction of 1‐alkenes was carried out in the presence of triethylsilane, ethanol and a catalytic amount of palladium(II) acetate or palladium on activated charcoal, at room temperature. This facile and efficient method affords high yields for hydrogenation of unsaturated alkenes to the corresponding alkanes. Then the carbon–carbon double bond isomerization of 1‐alkenes was tested using the same catalysts in the absence of solvent. The system palladium(II) acetate‐triethylsilane was found to be more effective compared with palladium on an activated charcoal–triethylsilane system at room temperature, while comparable results were obtained at 50 °C for both catalysts. Copyright © 2006 John Wiley & Sons, Ltd.
Use of bis(benzimidazolium)–palladium system as a convenient catalyst for Heck and Suzuki coupling reactions of aryl bromides and chlorides
Authors: Demir Serpil , Özdemir Ismail , Çetinkaya Bekir
Published: January 2006

Six new, sterically demanding bis(benzimidazolium) salts (2a–f) as NHC precursors have been synthesized and characterized. These salts, in combination with palladium acetate, provide active catalysts for the cross‐coupling of aryl chlorides and bromides under mild conditions in aqueous media. Copyright © 2006 John Wiley & Sons, Ltd.
Nickel (II) complexes supported by a fluorinated β‐diketiminate backbone ligand: synthesis, catalytic activity toward norbornene polymerization, and the oxygenated species
Authors: Li Yongfei , Jiang Long , Wang Lingyun , Gao Haiyang , Zhu Fangming , Wu Qing
Published: January 2006

The reaction of the lithium salt of backbone fluorinated β‐diketiminate ligands, ArNC(CF3)CHC(CF3) NArLi, with trans‐[NiCl(Ph)(PPh3)2] gives nickel (II) complexes, ArNC(CF3)CHC(CF3)NAr(Ph) (PPh3)Ni (Ar = 2, 6‐Me2C6H3: 1; 2, 6‐iPr2C6H3: 2). When activated by methylaluminoxane (MAO), both complexes polymerize norbornene rapidly via a vinyl‐type polymerization mechanism. Treatment of nickel complex 1 with oxygen gives rise to intramolecular aerobic hydroxylation. The oxygenated species 3 was characterized by X‐ray crystallography. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of temperature on electrical behavior of flyash‐filled epoxy gradient composites
Authors: Chand Navin , Jain Deepak
Published: January 2006

Functionally gradient composites of epoxy resin having different weight percentages of flyash were prepared under centrifugal force to obtain gradient in density, hardness, and electrical properties. Effect of temperature and frequency variation on dielectric constant (ε′), tan δ, and ac conductivity was determined by using a 4274 A Multi‐Frequency LCR meter. Electrical measurements were carried out in a temperature range from 40 to 180°C and in a frequency range from 1 to 100 kHz. It was observed that the dielectric constant and tan δ increased with increase in temperature and decreased with increase in frequency. The ac conductivity increases with increase in temperature and frequency. The increased weight percentage of flyash increased the compaction of flyash particle in the flyash‐rich phase of graded composites, which would have increased the dielectric constant (ε′), tan δ, and ac conductivity. Shore D hardness and density of the functionally gradient composites has also been determined and reported. A continuous increase in the hardness from 69 to 76 and density from 1.287 to 1.41 g/cc has been observed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1269–1276, 2006
Characterization and comparison of diblock and triblock amphiphilic copolymers of poly(δ‐valerolactone)
Authors: Lin Wen‐Jen , Wang Chia‐Ling , Juang Lee‐Wei
Published: January 2006

Three types of pegylated amphiphilic copolymers of poly(δ‐valerolactone) (PVL) were copolymerized with methoxy poly(ethylene glycol) (MePEG) and poly(ethylene glycol) (PEG4000 and PEG10,000), respectively. Pegylation of PVL allowed copolymers possessing amphiphilic property and efficiently self‐assembled to form micelles with a low critical micelle concentration (CMC) in the range of 10−7–10−8M. The average molecular weight of copolymers was in the range of 10,000–20,000 Da, and the polydispersity of copolymers was about 1.7–1.8. Higher mobility of low molecular weight PEG (i.e., MePEG and PEG4000) than high molecular weight PEG10,000 allowed valerolactone ring opening more efficient in terms of PVL/MePEG and PVL/PEG4000 copolymers possessing longer chain length in hydrophobic domain. Pegylated PVL with low CMC and triblock structure was preferred to encapsulate drug during micelle formation. Although all of these amphiphilic copolymers exhibited controlled release character, the micelles formed by triblock copolymer possessed a more stable core‐shell conformation than that by diblock copolymer, and resulted in the release of drug from triblock micelles slower than that from diblock micelles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1836–1841, 2006
Blended graft copolymer of carboxymethyl cellulose and poly(vinyl alcohol) with banana fiber
Authors: El‐Zawawy Waleed K.
Published: January 2006

Conducting hydrogel copolymer was prepared by graft copolymerization of carboxymethyl cellulose (CMC) and boric acid onto poly(vinyl alcohol) (PVA). The dielectric properties of CMC‐g‐PVA/prehydrolyzed banana blend have been investigated as a function of frequency, with special reference to pure prehydrolyzed banana. Also, the static bending for the blend was determined and no abrupt failure was observed. The dielectric properties measured were dielectric constant (ε′), dissipation factor (tan δ), and loss factor (ε″). At high frequencies, a transition in the relaxation behavior was observed, whereby the dielectric constant, loss tangent, and loss factor decreased with frequency. Experimental ε′ values of the blend are greater than those of prehydrolyzed banana. The dielectric behavior depends greatly on the nature of the present group, the crystallinity of the system, and the degree of hydrogen bonding between the different chains. The variation of the dielectric properties was correlated with blend morphology and also to the possibility for interfacial polarization that arises because of the differences in conductivities of the two phases. It was found from the infrared spectra that the incorporation of CMC‐g‐PVA copolymer decreases the crystallinity of the blend and also decreases the degree of hydrogen bonding, which results in a high dielectric constant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1842–1848, 2006
A toughened epoxy resin by silica nanoparticle reinforcement
Authors: Rosso P. , Ye L. , Friedrich K. , Sprenger S.
Published: January 2006

Within this study the influence of adding 5 vol % of silica nanoparticles, obtained via a sol–gel process, on an Araldite‐F epoxy was investigated. To characterize toughening effects, compact tension specimens were used to obtain KIC and GIC. Additionally, tensile strength and E‐Modulus were measured as well as differential scanning calorimetry and dynamic mechanical thermal analysis were carried out to evaluate the influence on the thermal properties of the epoxy because of addition of the particles. Electronic microscopy was used to check dispersion quality and fracture surfaces, in transmission mode and scanning mode, respectively. The addition of 5 vol %. silica‐nanoparticles could improve the stiffness and the toughness of an epoxy resin at the same time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1849–1855, 2006
Cationization of cellulose fabrics by polyallylamine binding
Authors: Wu Min , Kuga Shigenori
Published: January 2006

Novel anion exchange materials was prepared from cellulose fabrics (cotton‐ and rayon‐cloths) by binding polyallylamine to aldehyde groups introduced by partial oxidation of cellulose via sodium periodate treatment. Degree of oxidation (D.O.) was controlled to 2–8% by the amount of oxidant. Polyallylamine (MW: 60,000, 5000, and 1000) was bound to cellulose by reductive amidation via Schiff base formation. Amount of bound amino groups was determined by conductometric titration. With the same cellulose material and degree of oxidation, the level of cationization was strongly dependent on molecular weight of polyallylamine, its concentration, and the pH of reaction mixture. Influence of these factors could be interpreted based on the porous structure of cellulose and behavior of polyallylamine in the solution. In summary, the level of cationization could be maximized by using high concentration of low‐molecular weight polyallylamine under pH as high as possible. The maximum exchange capacity, ∼2.5 meq/g, was obtained by a combination of rayon cloth, oxidation degree of 8%, polyallylamine (MW: 1000) concentration of 10% (w/w) in the reaction mixture, and at pH 11.6. The cationized cellulose showed an adsorption capacity of 1.5 g hemoglobin/g cellulose. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1668–1672, 2006
Frequency‐dependent conductivity and dielectric permittivity of polyaniline/CeO2 composites
Authors: Parvatikar Narsimha , Ambika Prasad M. V. N.
Published: January 2006

The PANI/CeO2 composites were synthesized using in situ deposition technique by placing fine graded CeO2 in polymerization mixture of aniline. This is the single step polymerization process for the direct synthesis of emeraldine salt phase of polymer. Low frequency dielectric studies were carried out on pressed pellets of PANI/CeO2 with various concentrations of cerium oxide (10, 20, 30, 40, and 50 wt % of CeO2 in PANI). The results are interpreted in terms of polarons and bipolarons, which are responsible for the dielectric relaxation mechanism and frequency dependence of conductivity. It is found that a.c. measurements at room temperature may well serve as a parallel way to the time consuming d.c. conductivity versus temperature technique, to detect the thermal degradation of the transport properties in conducting polymers. It is observed that the charge motion via creation/annihilation of polarons and bipolarons increases as the weight percentage of the composite is increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1403–1405, 2006
Effects of ultrasonic oscillation on processing behaviors of PS, EPDM, and PS/EPDM blend
Authors: Li Jiang , Guo Shaoyun , Liang Mei
Published: January 2006

In this study, the extrusion processing behaviors of polystyrene (PS), ethylene–propylene–diene terpolymer (EPDM), and their blend (PS/EPDM, 80/20) were studied by using a special ultrasonic oscillation extrusion system developed in our laboratory. The die pressure and volume flow rate were measured at different ultrasonic intensities and screw rotation speeds. The dependences on ultrasonic intensity of die pressure, volume flow rate, and apparent viscosity of polymers, as well as die swell at the same screw rotation speed were investigated. The effects of screw rotation speed on the processing behaviors of polymers and their blend at the same ultrasonic intensity were also studied. The experimental results showed that in the presence of ultrasonic irradiation, the processibilities of polymers and their blend were improved. Their possible mechanism is discussed in this article. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1856–1863, 2006
Antibacterial property and mechanism of copolymer of acrylamide and quaternary salt of 4‐vinyl pyridine
Authors: Gao Baojiao , He Sanxiong , Guo Jianfeng , Wang Ruixin
Published: January 2006

The copolymers P(AM‐co‐4VP) of acrylamide (AM) and 4‐ vinyl pyridine (4‐VP) were synthesized. They had serial varied composition and molecular weight and then were quaternarized by using dimethyl sulfate. Two series of cationic polyacrylamide of quaternary pyridine salt‐type(Quaternary P(AM‐co‐4VP)'QPAV) had been synthesized, which have different cationic degree and molecular weight respectively. In this paper, the antibacterial property of QPAV was mainly investigated using Escherichia coli (E. coli) as model bacterium. Influences of various factors, such as cationic degree, molecular weight, and pH value on the antibacterial property of QPAV were examined with the method of the plate counting, and the antibacterial mechanism of QPAV was studied using the method of measuring the activity of β‐D‐galactosidase and TTC‐dehydrogenase. The experimental results show that QPAV possesses excellent antibacterial property, and the antibacterial ratio of QPAV for bacterium suspension of 109CFU/mL reached 100% under the conditions of concentration of 20mg/L and contact time of 5 min. The higher cationic degree of QPAV, the stronger is the antibacterial property. In a certain range of molecular weight, the higher the molecular weight of QPAV, the better is the antibacterial activity. The isoelectric point of protein of E. coli cell is probably pH = 4.4. When pH > 4.4, the antibacterial activity of QPAV increases as the pH increases, and antibacterial ratio reaches to 100% and remain nearly constant when pH > 5.3. When pH < 4.4, however, the apparent antibacterial ratio increases with the decrease of pH value, and this phenomenon may result from combined effects of QPAV and H+ ions on microbe. The experimental results reveal that the antibacterial effect of QPAV is not only based on a restraining action but also on a sterilization action. QPAV is believed to cause cell death by disrupting cell membranes, which allows release of the intracellular contents. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1531–1537, 2006
Influence of the porous morphology on the in vitro degradation and mechanical properties of poly(L‐lactide) disks
Authors: Sarazin Pierre , Virgilio Nick , Favis Basil D.
Published: January 2006

Poly(L‐lactide) (PLLA) materials having an interconnected porosity are proposed as an alternative to nonporous biomaterials. Such materials allow for the potential of modulating the degradation behavior and the mechanical properties. In this article, the preparation of porous PLLA disks or cylinders with 50 and 65% void volume is presented. It is demonstrated that both a symmetric and asymmetric porosity can be generated within the disk itself. In addition, open‐ and closed‐cell structures can also be prepared. The accelerated in vitro degradation on symmetric open‐cell porous PLLA disks and on the nonporous control indicate a similar behavior in terms of melting temperature and inherent viscosity of the remaining pieces of the specimens, but the crystallinity and the mass of the remaining fragments are much smaller for the porous specimens. The mechanical properties under compression are determined for open and closed‐cell porous cylinders, porous tubes, and for the nonporous PLLA. The results highlight the excellent mechanical integrity of the prepared porous structures and demonstrate that such materials could have potential for use as biomedical implants. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1039–1047, 2006
Ultraviolet radiation curable epoxy resin encapsulant for light emitting diodes
Authors: Kumar R. N. , Keem Lim Yoke , Mang Ng Chee , Abubakar Abusamah
Published: January 2006

Light‐emitting diodes are currently encapsulated by thermally curable epoxy resins. Thermal curing systems require long curing cycles at high temperatures. Further, because of viscoelastic behavior of the resin, the resin tends to “creep” along the connecting wires (Weisenberg effect), which causes solderability problem. The cured resin should be removed manually, which is time consuming and labor intensive. These problems are solved by the ultraviolet radiation curable systems. UV curing is an ultrafast reaction and takes place at room temperature. No creep behavior occurs due to the rapidity of the curing. The UV curing technique can result in higher productivity and energy saving than the thermal process. This article presents results on the development of UV curable formulations based on cycloaliphatic diepoxide, diglycidyl ether of bisphenol A, and epoxidized novolac induced by cationic photoinitiators. “Mixture experimental design” was employed to arrive at the optimum composition, which meets the stringent demands of performance characteristics and durability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1048–1056, 2006
Nonisothermal crystallization of poly(ethylene‐co‐glycidyl methacrylate)/clay nanocomposites
Authors: Huang Jiann‐Wen , Hung Hui‐Chuan , Tseng Kuo‐Shu , Kang Chiun‐Chia
Published: January 2006

The nonisothermal crystallization of poly(ethylene‐co‐glycidyl methacrylate) (PEGMA) and PEGMA/clay were studied by differential scanning calorimeter, at various cooling rates. Avrami model modified by Jeziorny, Ozawa mode and Liu model could successfully describe the nonisothermal crystallization process. Augis–Bennett model, Kissinger model, Takhor model, and Ziabicki model were used to evaluate the activation energy of both samples. It was found that the activation energy of PEGMA/clay nanocomposite was higher than that of neat PEGMA. Experimental results also indicated that the addition of modified clay might retard the overall nonisothermal crystallization process of PEGMA. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1335–1343, 2006
Chitosan: Aspects of fiber spinnability
Authors: El‐Tahlawy Khaled , Hudson Samuel M.
Published: January 2006

The preparation of useful fibers from chitosan remains an interesting challenge. Chitosan is easily solubilized in aqueous acids, but these solutions generally have high solution viscosities because of the polyelectrolyte effect. The high viscosity affects the processibility of chitosan during extrusion by wet‐spinning techniques. The coagulation rate, which also includes the regeneration of the free amine form of chitosan is also expected to be influenced by viscosity. In this study, the solution rheology of chitosan solutions was examined; our aim was to find the optimum compositions, in terms of chitosan, acid, and added salts, for spinnability. The diffusion of coagulants into chitosan spinning solutions is also reported. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1162–1168, 2006
A high‐resolution solid‐state NMR investigation of molecular mobility of poly(methyl methacrylate)/poly(vinyl pyrrolidone)/poly(ethylene oxide) ternary blends
Authors: Diniz Teresinha M. F. F. , Tavares Maria I. B.
Published: January 2006

The ternary blends of poly(methyl methacrylate)/poly(vinyl pyrrolidone)/poly(ethylene oxide), PMMA/PVP/PEO, were prepared by melting process, using a Haake plastograph, and nuclear magnetic resonance spectroscopy (NMR) was used as a methodology to characterize the molecular mobility of blend components, because NMR has several techniques that allow us to evaluate polymeric materials in different time scales. The NMR results showed that the blends were miscible on a molecular level. The values of proton lattice relaxation time in the rotating frame (T1ρH) indicate that the ternary blend interaction did not reduce the intermolecular distance, because it is dipole–dipole. The molecular motion of each component, even in the miscible amorphous phase and the addition of PEO, has a definitive effect on the PMMA molecular mobility. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1492–1495, 2006
Colloidal aggregation of aminoplastic polycondensation resins: Urea–formaldehyde versus melamine–formaldehyde and melamine–urea–formaldehyde resins
Authors: Despres A. , Pizzi A.
Published: January 2006

Colloidal particles formation followed by their clustering have been shown to be the normal way of ageing of aminoplastic resins, namely urea–formaldehyde (UF) resins, melamine–formaldehyde (MF) resins, and melamine–urea–formaldehyde (MUF) resins. Ageing or further advancement of the resin by other means such as longer condensation times causes whitening of the resin. This is a macroscopic indication of both the formation of colloidal particles and of their clustering. It eventually progresses to resins, which are mostly in colloidal, clustered state, followed much later on by a supercluster formation starting to involve the whole resin. The initial, filament‐like colloidal aggregates formed by UF resins have different appearance than the globular ones formed by MF resins. MUF resins present a short rod‐like appearance hybrid between the two. GPC has been shown to detect the existence of colloidal superaggregates in a UF resin, while smaller aggregates might not be detected at all. The star‐like structures visible in the colloidal globules of MF resins are likely to be light interference patterns of the early colloidal structures in the resins. These star‐like interference patterns become more complex with resin ageing or advancement due to the advancement of the resin to more complex aggregates, to eventually reach the stage in which filament‐like and rod‐like structures start to appear. The next step is formation of globular masses that are representative of the true start of physical gelation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1406–1412, 2006
Optimization of the properties of chitosan lactate/hyaluronan film
Authors: Kukolikova L. , Bakos D. , Alexy P. , Hanzelova S. , Zhong W.
Published: January 2006

Polyelectrolyte complexes represent attractive class of polymer‐based materials, finding an irreplaceable role in biomaterial preparation for tissue engineering or drug delivery beads. Mechanical properties, physical properties, and enzymatic degradation of the film prepared from chitosan lactate/hyaluronan polyelectrolyte complex, crosslinked with starch dialdehyde derivatives, were studied to optimize its composition. This work represents an example demonstrating how a minor modification of the modified complex composition changes final properties of the prepared film and emphasizes enormous variations in complex formation by crosslinking. To obtain sufficiently useful information, experimental design was employed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1413–1419, 2006
Fibrillation tendency of cellulosic fibers. VII. Combined effects of treatments with an alkali, crosslinking agent, and reactive dye
Authors: Zhang Wangsun , Okubayashi Satoko , Badura Wolfram , Bechtold Thomas
Published: January 2006

Lyocell woven fabrics were treated with crosslinking agents [1,3‐dimethyl‐4,5‐dihydroxyethylene urea (X1) and 1,3‐dimethylol‐4,5‐dihydroxyethylene urea (X2)], binders [polyacrylate (B1), anionic polyacrylate (B2), anionic polyurethane (B3), and aliphatic polyisocyanate (B4)], and polyfunctional reactive dyes in combination with alkali treatments. The effects of the treatment conditions, including the reagent types, the reagent concentrations, the process types (pretreatments or posttreatments with alkali), and the treatment combinations, on the fibrillation tendency and dyeing behavior in treated samples were investigated. Generally, the fibril number decreased with an increasing concentration of additives and decreased further with reactive dyeing. Fabrics treated with 45 g/L X1 (34 g/kg of fiber) or with 28 g/L X2 (21 g/kg of fiber) and dyed thereafter exhibited no fibrillation. Posttreatments with alkalis caused no changes in either the color shade or fibrillation tendency of crosslinked fabrics, although they enhanced the water retention capacity. The use of mixtures of binders B3 and B4 minimized the fibrillation, but the use of B4 led to changes in the color shade. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100:1176–1183, 2006
Pressure drop estimation for polyamide 6 flow through spinnerets and filters
Authors: Guštin A. , Zupančič A. , Mitsoulis E.
Published: January 2006

The pressure drop resulting from polyamide 6 flow through industrial spinnerets and wire‐mesh filters was examined as a possible parameter for improving spinning process constancy with experimental techniques and a numerical approach. The rheological characterization of the polymer melt was performed with a capillary rheometer and a controlled‐stress rotational rheometer equipped with a high‐temperature oven cell. Measurements in a nitrogen atmosphere were carried out at different temperatures and at various moisture contents to determine the effect of the postcondensation process on the rheological properties of the polymer melt. These experiments were used to collect all basic material information necessary to fit the data with the purely viscous Cross model and the viscoelastic Kaye, Bernstein, Kearsley, Zappas (K‐BKZ) model. A spinning pilot plant (consisting of an extruder, a gear pump, a pressure sensor, and a spin beam with several spin packs installed) was used to measure pressure drop values through industrial spinnerets and through two types of filters: (1) Dutch twilled weave filters and (2) sintered filters. Pilot plant tests on filters showed that in the examined range of melt throughputs, the pressure drop increased linearly with an increase in the melt flow rate for all the filters considered. The results with respect to the spinneret geometry led to the conclusion that the numerical simulations gave satisfactory predictions even for experimental data coming from complex systems such as spinning plants, as long as extensional properties were accounted for by the model. On the contrary, pressure drop predictions obtained from the Cross model underestimated the pilot plant values by approximately 20% because of the inability of the model to consider the extensional component of the flow. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1577–1587, 2006
Study of the preparation and properties of UV‐blocking fabrics of a PET/TiO2 nanocomposite prepared by in situ polycondensation
Authors: Han Keqing , Yu Muhuo
Published: January 2006

Poly(ethylene phthalate) (PET)/nano‐TiO2 composites prepared via in situ polymerization were spun into fiber by the melt‐spinning process. The dispersion of nanosized rutile TiO2 in the PET was studied using transmission electron microscopy (TEM) and scanning probe microscopy (SPM) techniques. The mechanical properties and the properties of ultraviolet (UV) protection were investigated. The results showed that rutile TiO2 can be dispersed uniformly by the in situ polycondensation process. The mechanical properties of PET/TiO2 fiber were slightly affected by adding nano‐TiO2. The UV‐ray transmittance of PET/nano‐TiO2 fabrics was below 10% in the UV‐A band and below 1% in the UV‐B band. And the ultraviolet protection factor (UPF) of PET/nano‐TiO2 fabrics was greater than 50. All these PET/TiO2 nanocomposite fabrics exhibited excellent UV‐blocking properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1588–1593, 2006
Study on in situ synthesis of konjac glucomannan/silver nanocomposites via photochemical reduction
Authors: Tian Dating , Hu Weibing , Zheng Zhen , Liu Hangbao , Xie Hong‐Quan
Published: January 2006

Konjac glucomannan (KGM)/Silver nanocomposites have been prepared directly in the dilute hydrosol of KGM using photochemical reduction of Ag+. The KGM/Ag nanocomposites have been characterized by means of Fourier transform infrared (FTIR) spectra, transmission electron microscopy (TEM), and thermalgravimetry (TG). The results of FTIR showed that the wavenumbers and the strengths of some characteristic peaks of KGM treated by silver nanoparticles were changed obviously, the characteristic peaks of the OH stretching and the CO (H) stretching became wider with increasing concentrations of the reactants, and the characteristic peaks of the OH stretching and the CO (H) stretching shifted to high wavenumbers with increasing time of photochemical reduction. The images of TEM indicated that Ag nanoparticles were finely dispersed inside the KGM films with different shapes, such as sphere‐like (average diameters of 9 ± 4 nm) and star‐like (edge lengths of about 20 nm), respectively. These suggested that the morphology and the agglomerated state of Ag nanoparticles in the composites changed with the conditions of the preparation, especially with the concentrations of Ag+ and KGM as well as the time of photochemical reduction. The KGM and KGM/Ag films had remarkably different thermal properties from the TG curves. The mechanism of interaction between the polysaccharide and the silver nanoparticles has also been generally discussed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1323–1327, 2006
Structural characterization of sulfur vulcanized deproteinized natural rubber by solid‐state 13C NMR spectroscopy
Authors: Sakdapipanich Jitladda T. , Kowitteerawut Tippawan , Tuampoemsab Surakit , Kawahara Seiichi
Published: January 2006

The structural changes in unfilled and filled vulcanized deproteinized natural rubber (DPNR), which is a highly purified natural rubber (NR), were investigated by solid‐state 13C NMR spectroscopy. The chemical shifts of new signal were assigned by calculation and compared with those observed by Koenig et al. for conventional vulcanized NR. The crosslink structure of sulfur vulcanized DPNR were similar to that of sulfur‐vulcanized NR for CV system assigned by Koenig et al. The increase in the relative intensities of signals between 45 and 58 ppm, which was assigned to monosulfidic and polysulfidic bonds, was concerned with the increase in crosslink density. In this case, the crosslink density was increased after aging, which might be due to incomplete curing. Furthermore, the solid‐state 13C NMR spectrum of the aged sulfur vulcanizate DPNR showed new signals at around 73 ppm, which is assignable to carbon attached to hydroxyl group because of thermal oxidation. It can provide more complete understanding of the final vulcanizate crosslink structure of DPNR vulcanizates. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1875–1880, 2006
Preparation, morphology, and mechanical properties of elastomers based on α,ω‐dihydroxy‐polydimethylsiloxane/poly(methyl methacrylate) blends
Authors: Dong Jian , Liu Zonglin , Feng Yongbin , Zheng Chao
Published: January 2006

α,ω‐Dihydroxy‐polydimethylsiloxane (PDMS)/poly(methyl methacrylate) (PMMA) blends were prepared by the radical polymerization of methyl methacrylate in the presence of PDMS, with benzoyl peroxide as the initiator. The PDMS/PMMA blends obtained by this method were a series of stable, white gums, which were vulcanized into elastomers at room temperature with methyl triethoxysilicane (MTES). The MTES dosage was much larger than the amount necessary for end‐linking the hydroxy‐terminated chains of PDMS, with the excess being hydrolyzed into crosslinked networks, which were similar to SiO2 and acted as fillers. Investigations were carried out on the elastomeric materials by extraction measurements, swelling measurements, and scanning electron microscopy. The extraction data showed that at each composition, the sol fraction was less than expected. The extracted materials were further studied with swelling measurements, which revealed that the material obtained from an elastomer with a higher PMMA content had an apparently larger equilibrium swelling degree. Scanning electron microscopy demonstrated that the elastomer system had a microphase‐separated structure consisting of PMMA domains within a continuous PDMS matrix. Moreover, the mechanical properties of the elastomeric materials were studied in detail. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1547–1553, 2006
New melamine–formaldehyde–ketone polymers. IV. Dissolution of melamine in reactive solvents prepared from methyl ethyl ketone
Authors: Głowacz‐Czerwonka Dorota , Kucharski Mieczysław
Published: January 2006

Reactive solvents of melamine were prepared from methyl ethyl ketone and formaldehyde in the presence of the catalyst triethylamine. The solubility of melamine in the resulting solvents was determined, and the mechanism of dissolution was explained with 1H‐NMR and IR spectroscopy. Preliminary experiments aimed at curing the melamine solutions in reactive solvents into melamine–formaldehyde–butanone resins are reported. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1496–1505, 2006
Preparation of a poly(3‐hexylthiophene)‐grafted indium tin oxide/poly(3‐hexylthiopene) composite and its conductivity–temperature characteristics
Authors: Liu Chuanjun , Oshima Kenji , Shimomura Masato , Miyauchi Shinnosuke
Published: January 2006

The temperature–conductivity characteristics of poly(3‐hexylthiophene) (P3HT) composites filled with P3HT‐grafted indium tin oxide (ITO) particles were investigated in this work. The ITO particles were first treated with a silane coupling reagent of 3‐aminopropyltriethoxysilane (APS), and then thiophene rings were introduced through a condensation reaction between the ending amino groups of APS and the carboxylic groups of thiophene‐3‐acetic acid. The composites were prepared by the polymerization filling of the 3‐hexylthiophene (3HT) monomer with the thiophene‐ring‐introduced ITO particles. Elemental analysis, Fourier transform infrared, and X‐ray photoelectron spectroscopy were used to confirm the grafting reaction on the ITO surface. The longer the polymerization time was or the higher the 3HT/ITO feeding ratio was, the more P3HT was grafted. The influence of the grafted amount on the electrical properties of ITO particles was attributed to the wrapping effect formed by the grafted P3HT on the surface of the ITO particles. The conductivity change of the P3HT‐grafted ITO/P3HT composites was proved to be subject to the change in the average gap width of ITO interparticles, which was determined by the filling ratio of P3HT to ITO in the polymerization and the volume expansion effect of a P3HT thin film between neighboring ITO particles during the heating process. In comparison with the ungrafted ITO/P3HT composites, the grafting treatment enhanced the interaction between the particles and polymer matrix, and this was helpful for obtaining a more homogeneous dispersion structure for the composites and thus afforded a higher positive temperature coefficient intensity and better reproducibility. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1881–1888, 2006
Modification of polyolefin films surface with sodium hypochlorite
Authors: Iguerb O. , Demoustier‐Champagne S. , Marchand‐Brynaert J. , Daoust D. , Sclavons M. , Devaux J.
Published: January 2006

Surface modification of high‐density‐polyethylene (HDPE) and linear‐low‐density polyethylene (LLDPE) films is promoted by sodium hypochlorite solutions using two different processes (I and II). Such an oxidation system introduces limited amounts of carbonyl–carboxyl and hydroxyl groups onto the surface of hydrocarbon polymers. FTIR, XPS, and SEM were used to assess the efficiency of the oxidation. The hydrophilicity of the studied surfaces was investigated by the sessile drop technique and the Wilhelmy plate and a plausible oxidation mechanism is proposed.

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© 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1184–1197, 2006
Evaluation of the microstructure and melting behavior of drawn polypropylene fibers with a microthermal analyzer
Authors: Ye Jiping , Hasegawa T. , Suzuki A.
Published: January 2006

The strong correlation of melting behavior with the microstructure of original and zone‐drawn isotactic polypropylene fibers was evaluated by microthermal analysis (micro‐TA) combined with wide‐angle X‐ray diffraction analysis. The crystal structure of both the original and zone‐drawn fibers was a monoclinic α‐form with a ∼ 0.64 nm, b ∼ 2.03 nm, and c ∼ 0.65 nm. In contrast to the absence of any oriented polymer molecules in the original fiber, the polymer molecules in the zone‐drawn fiber were extended and highly oriented in at least two different states; one arranged along the drawn axis and the other at 40° to the drawn axis. The micro‐TA‐derived melting points corresponded to these microstructural changes caused by the zone‐drawing process and differed from the melting points obtained by differential scanning calorimetery. The micro‐TA melting point of 140°C corresponded to the z‐e‐p melting point of the original fiber, being much lower than the conventional differential scanning calorimetery melting point of 163°C. As for the zone‐drawn fiber, an increase of 19°C in the melting temperature revealed its high orientation level, and the appearance of three elevated melting peaks (161, 167, and 178°C) at the highest heating rate (1500°C/min) coincided with its several oriented states. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1306–1311, 2006
Block copolymerization of poly(diethylene glycol phthalic anhydride) and methyl methacrylate initiated by potassium diperiodatonickelate(IV)
Authors: Liu Yinghai , Bai Libin , Zhou Weiqi , Liu Yuanwei , Li Yanxiang , Deng Kuilin
Published: January 2006

Block copolymers of methyl methacrylate (MMA) and poly(diethylene glycol Phthalic Anhydride) (PPAG) was synthesized using a novel redox system—potassium diperiodatonickelate(IV) [DPN]/PPAG system in an alkaline medium. Block copolymers with high percentage of blocking were obtained, which indicated that DPN/PPAG redox system was an efficient initiator for this blocking. Effects of different factors on the blocking parameters were examined. The overall activation energy of this blocking was calculated to be 55.12 kJ/mol. The structure of the block copolymer was determined by infrared, X‐ray diffraction, and scanning electron microscope (SEM). A mechanism is proposed to explain the generation of radicals and the initiation of block copolymerization. The block copolymer was used as the compatibilizer in blends of PMMA and Nylon6. The SEM photographs show that the block copolymer greatly improved the compatibility of the blend. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1312–1317, 2006
Methacrylic acid and dodecyl methacrylate (MAc‐DMA) hydrogel for enhanced catalytic activity of lipase of Bacillus coagulans MTCC‐6375
Authors: Kanwar Shamsher S. , Chauhan Ghansham S. , Chimni Swapandeep S. , Chauhan Sandeep , Rawat Gajendra S. , Kaushal Rajeev K.
Published: January 2006

An alkaline thermotolerant bacterial lipase of Bacillus coagulans MTCC‐6375 was purified and immobilized on a methacrylic acid and dodecyl methacrylate (MAc‐DMA) hydrogel. The lipase was optimally bound to the matrix after 20 min of incubation at 55°C and pH 9 under shaking conditions. The matrix‐bound lipase retained approximately 50% of its initial activity at 70–80°C after 3 h of incubation. The immobilized lipase was highly active on medium chain length p‐nitrophenyl acyl ester (C: 8, p‐nitrophenyl caprylate) than other p‐nitrophenyl acyl esters. The presence of Fe3+, NH4+, K+, and Zn2+ ions at 1 mM concentration in the reaction mixture resulted in a profound increase in the activity of immobilized lipase. Most of the detergents partially reduced the activity of the immobilized lipase. The immobilized lipase performed ∼62% conversion in 12 h at temperature 55°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1420–1426, 2006
Alanine containing porous beads for mercury removal from artificial solutions
Authors: Şenel Serap , Kara Ali , Karabakan Abdülkerim , Denizli Adil
Published: January 2006

N‐methacryloyl‐(L)‐alanine (MALA) was synthesized by using methacryloyl chloride and alanine as a metal‐complexing ligand or comonomer. Spherical beads with an average diameter of 150–200 μm were obtained by suspension polymerization of MALA and 2‐hydroxyethyl methacrylate (HEMA) conducted in an aqueous dispersion medium. Poly(HEMA–MALA) beads were characterized by SEM, swelling studies, surface area measurement, and elemental analysis. Poly(HEMA–MALA) beads have a specific surface area of 68.5 m2/g. Poly(HEMA–MALA) beads with a swelling ratio of 63%, and containing 247 μmol MALA/g were used in the removal of Hg2+ from aqueous solutions. Adsorption equilibrium was achieved in about 60 min. The adsorption of Hg2+ ions onto PHEMA beads was negligible (0.3 mg/g). The MALA incorporation into the polymer structure significantly increased the mercury adsorption capacity (168 mg/g). Adsorption capacity of MALA containing beads increased significantly with pH. The adsorption of Hg2+ ions increased with increasing pH and reached a plateau value at around pH 5.0. Competitive heavy metal adsorption from aqueous solutions containing Cd2+, Cu2+, Pb2+, and Hg2+ was also investigated. The adsorption capacities are 44.5 mg/g for Hg2+, 6.4 mg/g for Cd2+, 2.9 mg/g for Pb2+, and 2.0 mg/g for Cu2+ ions. These results may be considered as an indication of higher specificity of the poly(HEMA–MALA) beads for the Hg2+ comparing to other ions. Consecutive adsorption and elution operations showed the feasibility of repeated use for poly(HEMA–MALA) chelating beads. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1222–1228, 2006
Mineralization of hydroxyapatite on a polymer substrate in a solution supersaturated by polyelectrolyte
Authors: Iwatsubo Takashi , Kusumocahyo Samuel P. , Kanamori Toshiyuki , Shinbo Toshio
Published: January 2006

In this article, a new method to construct composites of hydroxyapatite (HAP) and polymer material is introduced. A previously developed method for mineralization of CaCO3 on a polymer substrate was applied to HAP. A solution that contained Ca2+, PO43–, and OH‐ ions was supersaturated with polyacrylic acid (PAA) that, at the same time, formed a polymer complex with the substrate, a polyvinyl alcohol (PVA) film, at the substrate surface. In this thin surface layer, nucleation of HAP took place. Subsequently, the disklike domains of HAP that were generated spread until they covered the PVA film surface. By regulating the pH of the supersaturated solution at around 7.4, the domain size decreased and the quantity of deposited material increased. Approximately 20 mg of HAP coating was obtained on a PVA film of 1 cm radius when the film was soaked in single 200 mL batch of the supersaturated solution for 21 days. The junction between HAP layer and PVA substrate film was found to be very firm. When a crosslinked PVA/PAA was used as the substrate, the film swelled in the supersaturated solution to form a hydrogel. Then mineralization took place within the gel, and a transparent monolithic composite of HAP and the polymer network was obtained. In 13 days, the weight increase was 29 mg, which corresponded to a 71 wt % HAP mineralization ratio of the composite. By changing crosslinking degree and HAP mineralization ratio, the flexibility of composite will be controlled in a wide range. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1465–1470, 2006
Synthesis and characterization of poly(butylene terephthalate) nanocomposite fibers: Thermo‐mechanical properties and morphology
Authors: Chang Jin‐Hae , Mun Mu Kyung
Published: January 2006

Nanocomposites of poly(butylene terephthalate) (PBT) with the organoclay C12PPh‐MMT were prepared using in situ intercalation polymerization. Hybrids with various organoclay contents were processed for fiber spinning to examine their thermal behavior, tensile mechanical properties, and morphologies for various draw ratios (DRs). The thermal properties (Tg, Tm, and TDi) of the hybrid fibers were found to be better than those of pure PBT fibers and were unchanged by variation of the organoclay loading up to 2 wt %. However, these thermal properties remained unchanged for DRs ranging from 1 to 18. Most clay layers were dispersed homogeneously in the matrix polymer, although some clusters were also detected. The tensile properties of the hybrid fibers increased gradually with increasing C12PPh‐MMT content at DR = 1. However, the ultimate strengths and initial moduli of the hybrid fibers decreased markedly with increasing DR. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1247–1254, 2006
Synthesis and characterization of poly(ethylene‐co‐trimethylene terephthalate)s
Authors: Wei Gaofu , Wang Liuyang , Chen Guokang , Gu Lixia
Published: January 2006

Taking advantage of a melt polycondensation process, a series of copolyesters composed of pure terephthalate acid (PTA), ethylene glycol (EG), and 1,3‐propanediol (1,3‐PDO) were synthesized. The component, molecular weight, molecular weight distribution, and thermal properties of the copolymers were characterized. The results show that the contents of trimethylene terephthalate (TT) units in the resulting copolyesters are higher than PDO compositions in original diol. Oligomer content in the copolyesters varies with the compositions and attains a minimum value when the TT ingredient is 49.52 mol %. The glass transition temperature (Tg) of the copolyesters varies from 78.5°C for PET (polyethylene terephthalate) to 43.5°C for PTT (polytrimethylene terephthalate) and decreases monotonically with the components. The copolyesters are amorphous copolymers when TT content is in the range of 32.4–40.8 mol %, as calculated from the melting enthalpy (ΔHm) measured via differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1511–1521 2006