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Cast Films (cast + film)
Selected AbstractsThiophene,Benzothiadiazole Co-Oligomers: Synthesis, Optoelectronic Properties, Electrical Characterization, and Thin-Film PatterningADVANCED FUNCTIONAL MATERIALS, Issue 3 2010Manuela Melucci Abstract Newly synthesized thiophene (T) and benzothiadiazole (B) co-oligomers of different size, alternation motifs, and alkyl substitution types are reported. Combined spectroscopic data, electrochemical analysis, and theoretical calculations show that the insertion of a single electron-deficient B unit into the aromatic backbone strongly affects the LUMO energy level. The insertion of additional B units has only a minor effect on the electronic properties. Cast films of oligomers with two alternated B rings (B,T,B inner core) display crystalline order. Bottom-contact FETs based on films cast on bare SiO2 show hole-charge mobilities of 1,×,10,3,5,×,10,3,cm2 V,1s,1 and Ion/Ioff ratios of 105,106. Solution-cast films of cyclohexyl-substituted compounds are amorphous and do not show FET behavior. However, the lack of order observed in these films can be overcome by nanorubbing and unconventional wet lithography, which allow for fine control of structural order in thin deposits. [source] Synthesis, properties, and sulfonation of novel dendritic multiblock copoly(ether-sulfone)JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2008Sumiko Matsumura Abstract Multiblock copoly(ether-sulfone)s (PESs) bearing anchor units for the construction of dendritic blocks were synthesized by two-step reactions: (1) synthesis of PES block with both phenoxide end-groups; (2) chain extension and end-capping of the block by use of excess novel hexafunctional agent, hexakis(4-(4-fluorophenylsulfonyl)phenyl)benzene. The optimum average block length (n) and amount (x) of the hexafunctional agent used for the synthesis of high-molecular-weight PES without crosslinking were n = 26 and x = 2.6 equiv, respectively. The dendritic blocks in the PES were constructed by the aromatic nucleophilic substitution reaction of the activated aromatic fluoride groups on the anchor units using 4-tritylbenzenethiol. The clean substitution of the fluoride groups in the PES was confirmed by 1H NMR and 19F NMR. Three sulfonic acid groups were introduced on the pendant phenyl rings of the trityl groups in the PES by the reaction with chlorosulfonic acid. This is the first example of a dendritic PES bearing clusters of sulfonic acid groups only on the dendritic blocks. Cast films of presulfonated dendritic PES were strong and flexible, however, the membranes of sulfonated dendritic PES were brittle so that the conductivity measurements were not performed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6365,6375, 2008 [source] Influence of co-monomer structure on properties of co-polyamide packaging filmsPACKAGING TECHNOLOGY AND SCIENCE, Issue 1 2002P. Scarfato Abstract In this work a series of co-polyamides were prepared by random polymerization of ,-caprolactam in presence of four different co-monomers at a percentage of 5% w/w, with the aim of verifying their suitability as film-forming materials. The effects of structural changes induced in the ,-caprolactam homopolymer by co-monomers were evaluated in both molten and solid states. Rheological tests in shear and elongational flow were performed to evaluate the processability of co-polyamides. Cast films were obtained and their thermal, mechanical and transport properties were evaluated to establish the performances of the co-polyamides in view of packaging applications. The results indicate that co-polyamide films having a partially aromatic structure display the best mechanical performances and show a significant improvement in barrier properties to gases compared to the homopolymer. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effect of ,-irradiation on the physical properties and dyeability of poly(vinyl butyral) blends with polystyrene and poly(ethylene glycol)POLYMER COMPOSITES, Issue 6 2008Horia M. Nizam El-Din Cast films of polymer blends essentially based on poly(vinyl butyral) (PVB) and equal ratios of polystyrene (PS) and poly(ethylene glycol) (PEG) were prepared from benzene and butyl alcohol solutions of the individual polymers. The effect of ,-irradiation on the thermal decomposition and tensile mechanical properties was investigated. Moreover, the effect of ,-irradiation on the dye affinity of PVB/PS and PVB/PEG for basic and acid dyestuffs was studied. The thermogravimetric analysis (TGA) study showed that the unirradiated PVB polymer films prepared in benzene displayed higher thermal stability than the same polymer films prepared in butanol. However, in all cases the thermal stability was found to increase with increasing ,-irradiation dose. On the other hand, PVB/PS blend possesses higher thermal stability than PVB/PEG, as shown from the determination of the weight loss (%) at different heating temperatures, the temperatures of the maximum rate of reaction and the activation energy. While, pure PS films showed the stress-strain behavior of brittle polymers, PVB/PS films showed the behavior of tough polymers with yielding properties. The results of dyeing clearly showed that the solvent type, blend composition, and irradiation dose are determining factors for the dye affinity for basic or acid dyes. For example, unirradiated PVB films prepared from butanol displayed a higher affinity for the basic and acid dyes than the same polymer prepared from the same benzene. However, PVB prepared from butanol showed higher affinity to the dyes than PS prepared from the same solvent. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] The Effect of Orientation on Extrusion Cast Metallocene Polyethylenes and the Role of Processing Conditions in the Die Swell of Metallocene and Conventional PolyethylenesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1-2 2004B.G. Millar Cast films were prepared from a range of metallocene polyethylenes (mPEs) of varied co-monomer types (hexene, octene) using a Killion single-screw extruder, using different haul off speeds (8,4 m/min) and die gaps (700,250 m,m). Samples with greater orientation in one direction had increased tensile strength and shrinkage in that direction. DSC analysis showed crystallinity to decrease with decreasing haul of speed. Extrusion of mPEs and conventional linear low density polyethylenes (LLDPEs) by single capillary rheology showed that die swell increased with increasing extrusion rate and decreasing melt temperature. Increased die swell was found for the broader molecular weight distribution (M.W.D.) LLDPEs and in the higher molecular weight resins. Furthermore, long chain branching was found to increase die swell. [source] Anti-thrombogenicity of styrene-butadiene-styrene triblock copolymer grafted with poly(ethylene glycol)sJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Masanobu Nagura Abstract We transformed hydrophobic/hydrophobic styrene/butadiene/styrene tri-block copolymer (SBS) to hydrophobic / hydrophilic microphase-separated surfaces by grafting with hydrophilic poly(ethylene glycol) (PEG) on poly(butadiene) (PB) domain via hydrocarboxylation and hydrobromination and investigated the anti-thrombogenicity of these surfaces. In the case of SBS cast film from toluene solution, PEG was densely grafted because of the development of an unevenness on the order of several 10 nm on the surface, which had a huge surface area in comparison with poly(butadiene) rubber with its uniformly smooth surface. Grafted PEG (molecular weight = 600) was found to clearly inhibit adhesion and activation of platelets and coagulation of the whole blood component, which is indicative of anti-thrombogenicity. These properties correspond to a surface coated by a copolymer of 2-methacryloyl-oxyethyl phosphorylcholine and n -butyl methacrylate, which is well known to be the best excellent anti-thrombogenic material in the world. Melt-molded SBS film, which also has an uneveness on the order of several 10 nm, showed similar excellent anti-thrombogenicity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Chitosan,alginate,CaCl2 system for membrane coat applicationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2001Lishan Wang Abstract Water-based formulations are preferred for membrane coat application because they do not require the use of noxious solvents. A novel aqueous chitosan,alginate,CaCl2 system was evaluated as a potential formulation to produce water-insoluble membranes of biodegradable polymers. Chitosan,alginate coacervates were prepared by controlled reaction of chitosan (0.25% w/v) and sodium alginate (0.25% w/v) solutions. Coherent membranes were obtained by casting and drying the coacervates suspended in aqueous CaCl2 solutions (0.05,0.07% w/v). Increasing the calcium content did not modify membrane thickness (25,26 ,m), but reduced the water vapor transmission rate from 658 to 566 g/m2/day, and improved the tensile strength of the membranes from 9.33 to 17.13 MPa. Differential scanning calorimetry, Fourier transform infrared spectroscopy, and elemental analyses of the chitosan,alginate coacervates indicated they were stable for up to 4 weeks of storage in distilled water at ambient temperature. Membranes of the stored coacervates required less calcium to attain maximum mechanical strength. They also had higher water vapor transmission rates than corresponding films prepared from fresh coacervates. On the basis of the properties of the cast film and its storage stability, the chitosan,alginate,CaCl2 system can be considered for potential membrane coat application. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1134,1142, 2001 [source] Synthesis and chiroptical properties of ,-conjugated polymer consisting of dihydropentahelicene units with axial chiralityJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 8 2010Masahiro Abe Poly(dihydropentahelicene) or poly(1,1,-naphthalene- 4,4,-diyl) with axial chirality was prepared. The polymer showed a large circular dichroism of 1.8 degrees/,m in a cast film. [source] Image Contrast Inversion of a Solvent Cast SEBS FilmCHINESE JOURNAL OF CHEMISTRY, Issue 1 2006Xia Han Abstract The image contrast inversion was investigated in detail when soft polymeric materials were imaged with tapping mode atomic force microscopy (TM-AFM). Solvent cast film of polystyrene- block -poly(ethylene/butylene)- block -polystyrene (SEBS) triblock copolymers was used as a model system in this study, which showed phase separation domains with a size of several tens of nanometers. AFM contrast reversal process, through positive image, to an intermediary and till negative image, could be clearly seen in height images of the soft block copolymer using different tapping force. The higher tapping force would lead to not only contrast inversion, but also the different size of the microdomains and different roughness of the images. Moreover, contrast inversion was explained on the basis of attractive and repulsive contributions to the tip-sample interaction and indentation of the soft domains. [source] Dispersion of Graphene Sheets in Organic Solvent Supported by Ionic InteractionsADVANCED MATERIALS, Issue 17 2009Yanyu Liang Organic solution-processable graphene sheets were prepared using a large-scale novel approach based on a transfer process assisted by ionic interactions. Smooth monolayer graphene sheets were easily fabricated on a substrate from organic solution. Such a noncovalent functionalization preserves the extended aromatic conjugation of reduced graphene sheets, giving rise to high-conductivity cast films. [source] Copper-Mediated Aryl-Aryl Couplings for the Construction of Oligophenylenes and Related HeteroaromaticsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 7-8 2009Masahiko Iyoda Abstract Efficient methods for the syntheses of biaryls by the copper-mediated homocoupling of arylmetals are summarized. First, a smooth transmetallation between arylzinc halides and copper(II) salts has been employed for the selective homocoupling of arylzinc halides to produce either biphenylenes or tetraphenylenes. This reaction has been applied to the synthesis of cyclic oligothiophenes. Second, an efficient method for the homocoupling of aryl halides by the electron-transfer (ET) oxidation of Lipshutz cuprates [Ar2Cu(CN)Li2] with organic electron acceptors has been developed. The ET oxidation of cuprates with 1,4-benzoquinones proceeds smoothly to afford the corresponding coupling products in moderate to high yields. The ET oxidation of cuprates has been applied to the synthesis of either thiophene- or benzene-fused 10-membered ring cyclophanes. For the synthesis of macrocyclic cyclophanes, a linear CCuC structure of Lipshutz cuprates should be maintained in the dimetallacyclic intermediates to efficiently produce large-ring cyclophanes. Moreover, nonaphenylenes and dodecaphenylenes have been synthesized using the ET oxidation of cuprates with duroquinone. Interestingly, hexadodecyloxynonaphenylene exhibits different nanostructures between fibrous materials in solution and cast films on a surface. Films of this compound can detect vaporized nitroaromatics such as dinitrobenzene and trinitrobenzene. [source] Studies on , to , phase transformations in mechanically deformed PVDF filmsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Vijayakumar R. P. Abstract PVDF cast films were drawn at different temperatures to different draw ratios at constant draw rate to understand the mechanism of , to , phase transformation during mechanical deformation. WAXD and FTIR studies were carried out to determine the formation and content of , phase in the drawn films. Lower stretch temperatures gave higher fractions of , phase. The cast PVDF films were also drawn at suitable temperatures below the PVDF ambient melting point to the draw ratio of 6.4. The highest fraction of , phase obtained in these ultra drawn films was 0.98. SALS studies carried out for films at different stretch ratios show the change in spherulitic structure with the stretching parameters and give information for the understanding of phase transformation during stretching of PVDF films. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Structural determination of ethylene-propylene-diene rubber (EPDM) containing high degree of controlled long-chain branchingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009Susanta Mitra Abstract This work highlights an attempt to characterize the degree and nature of long-chain branching (LCB) in an unknown sample of ethylene-propylene-diene rubber (EPDM). Two EPDM rubbers selected for this study were comparable in comonomer compositions but significantly different with respect to molar mass and the presence of LCB. Both rubbers contained 5-ethylidene-2-norbornene (ENB) as diene. Solution cast films of pure EPDM samples were used for different characterization techniques. 1H-NMR, and 13C-NMR were used for assessing the comonomer ratios and LCB. Size exclusion chromatography (SEC) equipped with triple detector system was used to determine the molar mass (both absolute and relative) and polydispersity index (PDI). Presence of branching was also detected using sec-viscometry. Rheological analysis has also been used for characterizing LCB. Finally, on the basis of the experimental findings and the available theories, an attempt was made to identify the chemical nature and degree of LCB. This study reveals the possibility of detailed characterization of molecular architecture of EPDM containing LCB by comparing with an essentially linear EPDM in light of an existing theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Characterization of chitosan/citrate and chitosan/acetate films and applications for wound healingJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Junichi Tanigawa Abstract In this work, we aimed to develop a scaffold of chitosan (CS) with a porous sponge structure for an artificial skin. The scaffolds were prepared from both CS/citric and CS/acetic solutions. In addition, the cast films were also prepared from the same solutions to compare some of their properties. They were characterized using WAXD, FTIR, DSC, tensile measurements, and SEM observation. It was found that CS/acetate had low crystallinity but CS/citrate was in an amorphous state, resulting in a large ductility with rubbery softness. Despite the different morphologies of CS/citrate and CS/acetate scaffolds, both scaffolds exhibited the wound healing effect available for tissue engineering. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Supramolecular control of spin-crossover phenomena in lipophilic Fe(II)-1,2,4-triazole complexesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 17 2006Keita Kuroiwa Abstract The spin-crossover properties of lipophilic, supramolecular Fe(II) complexes bridged by 4-(3-dodecyloxy)propyl-1,2,4-triazole [Fe(II)(1)3Cl2] were investigated in chloroform and cast films. A purple low-spin (LS) complex in a powdery form was transformed into pale yellow high-spin (HS) polymers by dissolution in chloroform. The formation of lipophilic molecular wires in chloroform was observed with transmission electron microscopy. The casting of chloroform solutions onto solid supports produced purple, transparent films (LS state). The cast films exhibited sluggish spin-crossover (LS , HS) behavior without thermal hysteresis. On the other hand, the cocasting of equimolar dodecanol or tetradecanol with Fe(II)(1)3Cl2 produced composite films in which alcohol molecules were bound to the complex by ionic hydrogen bonding (ROH···Cl,) and van der Waals interactions. At room temperature, the cast films exhibited regular lamellar structures before and after alcohol doping; this was confirmed by wide-angle X-ray diffraction measurements. Interestingly, the Fe(II)(1)3Cl2/CnOH (n = 12 or 14) ternary films showed a reversible abrupt spin crossover accompanied by thermal hysteresis. The observed bistability was related to dynamic structural transformations between lamellar and hexagonal structures. This study provides a novel supramolecular approach to designing spin-crossover polymer films with controlled thermal bistability. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5192,5202, 2006 [source] Novel thermally stable poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s for luminescent and electrochromic materialsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 15 2005Guey-Sheng Liou Abstract We describe the preparation, characterization, and luminescence of four novel electrochromic aromatic poly(amine hydrazide)s containing main-chain triphenylamine units with or without a para-substituted N,N -diphenylamino group on the pendent phenyl ring. These polymers were prepared from either 4,4,-dicarboxy-4,- N,N -diphenylaminotriphenylamine or 4,4,-dicarboxytriphenylamine and the respective aromatic dihydrazide monomers via a direct phosphorylation polycondensation reaction. All the poly(amine hydrazide)s were amorphous and readily soluble in many common organic solvents and could be solution-cast into transparent and flexible films with good mechanical properties. These poly(amine hydrazide)s exhibited strong ultraviolet,visible absorption bands at 346,348 nm in N -methyl-2-pyrrolidone (NMP) solutions. Their photoluminescence spectra in NMP solutions or as cast films showed maximum bands around 508,544 and 448,487 nm in the green and blue region for the two series of polymers. The hole-transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. All obtained poly(amine hydrazide)s and poly(amine-1,3,4-oxadiazole)s exhibited two reversible oxidation redox couples at 0.8 and 1.24 V vs. Ag/AgCl in acetonitrile solution and revealed excellent stability of electrochromic characteristics, changing color from original pale yellow to green and then to blue at electrode potentials of 0.87 and 1.24 V, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3245,3256, 2005 [source] Structural, Electrical, Mechanical, and Thermal Properties of Electrospun Poly(lactic acid)/Polyaniline Blend FibersMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2010Paulo H. S. Picciani Abstract Conducting electrospun fiber mats based on PLA and PAni blends were obtained with average diameter values between 87 and 1 006,nm with PAni quantities from 0 to 5.6 wt.-%. Structural characteristics of fiber mats were compared to cast films with the same amount of PAni and studied by SEM, SAXS, and AFM. Thermal properties of fiber mats and cast films were compared by DSC analyses. Mechanical properties of fiber mats were also evaluated. It was found that electrospinning process governs the crystal structure of the fibers and strongly affects fiber properties. New properties of PLA/PAni blends are reported due to the size fiber reduction. [source] Stretching induced phase transformations in melt extruded poly(vinylidene fluoride) cast films: Effect of cast roll temperature and speedPOLYMER ENGINEERING & SCIENCE, Issue 12 2007Milind V. Mhalgi Melt extruded poly(vinylidene fluoride) cast films were prepared at different cast roll temperatures and speeds to study the effect of casting temperature and preorientation of the melt on the ,- to ,-phase transformation in these films after uniaxial stretching. X-ray and fourier transform infrared spectroscopy were used to identify the crystalline phases. The unstretched films were characterized using small angle light scattering (SALS). The films were stretched to a stretch ratio of 4.2 and at 80°C. Birefringence of the films and the fraction of ,-phase [F(,)] formed after uniaxial stretching increased with stretch ratio. The films showed increased crystallinity after stretching. For the films prepared at different cast roll temperatures, there was little change in F(,) in the films having a cast roll temperature between 75 and 120°C, but for the film with a cast roll temperature of 130°C F(,) decreased considerably. For the films prepared at different cast roll speeds, the F(,) increased with stretch ratio as well as with cast roll speed for a fixed stretch ratio. The primary effect of changing both the parameters is a change in the average spherulitic radius (R), in the unstretched films measured using SALS. The F(,) obtained correlated well with R and lower spherulitic radii resulted in the higher conversion to the ,-phase. POLYM. ENG. SCI., 47:1992,2004, 2007. © 2007 Society of Plastics Engineers [source] Optical properties of highly transparent polypropylene cast films: Influence of material structure, additives, and processing conditionsPOLYMER ENGINEERING & SCIENCE, Issue 4 2006Katharina Resch Polypropylene homopolymers and ethylene/propylene-random-copolymers formulated with and without anti-blocking additives were extruded to cast films with an industrial scale extruder equipped with a soft box, a specific air knife that expels a higher volume of air at lower velocity. The films were analyzed as to their optical properties haze and clarity. A comprehensive topographical characterization was performed using atomic force microscopy (AFM) and confocal microscopy. To obtain morphological information on a nanometer scale AFM phase imaging, micro-thermal analysis and small angle X-ray scattering (SAXS) were done. A significant effect of additives and processing conditions on the film topography and the optical properties was revealed. The films without anti-blocking and antacid aids showed the best optical properties and lowest vertical roughness fluctuations. In contrast, the addition of anti-blocking and antacid aids reduced the optical properties associated with an increase in surface roughness. While for films without anti-blocking aids an enhanced soft box condition resulted in lower vertical fluctuations of roughness and better optical properties, the behavior was in reverse for films with anti-blocking aid. By means of SAXS crystalline lamellae with a thickness of about 2.5 nm were detected. High-resolution phase imaging AFM yielded thicker crystal lamellae on the film surface. POLYM. ENG. SCI., 46:520,531, 2006. © 2006 Society of Plastics Engineers. [source] | |||||||||||||||||||||||||