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The shear-induced crystallization behavior in isotactic polypropylene (iPP) composite melt containing short aramid fibers was investigated by means of WAXD (wide-angle X-ray diffraction) and SAXS (small-angle X-ray scattering) techniques using synchrotron radiation. The study was carried out in a post-shear isothermal crystallization mode at temperatures of 140–160°C. Parameters pertaining to the...
The effects of long-range connectivity between urea hard domains on the microphase morphology and mechanical properties of novel, segmented, non-chain extended polyureas based on single isocyanate molecules were analyzed. This was achieved by systematic disruption of the intermolecular bidentate hydrogen bonding between the urea hard segments by the incorporation of a hydrogen bond screener, LiCl...
The degradation of melt polyolefin elastomer (POE) at the presence of dicumyl peroxides (DCP) was estimated at elevated temperature in oscillatory shear flow. Large amplitude oscillatory shear (LAOS) experiments followed by Fourier transform rheology (FTR) were carried out to detect and evaluate the branching architecture of the products. The third complex harmonic (I 3∗ ) and other two...
Epoxy resin based on diglycidyl ether of bisphenol A and varying content of hydroxyl terminated polybutadiene were cured using an anhydride hardener. The ultimate aim of the study was to modify the brittle epoxy matrix by liquid rubber to improve the toughness characteristics. Chemorheological analysis of the modified network was performed to understand the physical transformations taking place during...
In this paper, we describe the application of the constrained rolling process to produce highly oriented polyacetal bars with enhanced mechanical properties. In this process, the heated polymer billet is deformed in a channel formed in the circumference of the bottom roll that provides lateral constraint to the material as it deforms. It is a process that has attracted interest due to its capability...
Complexation between poly(sodium acrylate) (PANa) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide methiodide (ETC) in water, which leads to the formation of vesicle-like aggregates, was studied. Different from reported nano-aggregates of polymer complexes that may dissociate when being stimulated, the nano-aggregates of PANa/ETC complexes dissociate automatically in the aqueous solution at ambient...
A new series of pyrroles bearing bile acid moieties were synthesized and electrochemically polymerized in acetonitrile with tetrabutylammonium hexafluorophosphate (TBAFP 6 ) as the supporting electrolyte. It is found that these functionalized monomers could form polypyrrole films, but their electrochemical properties and the stability of the films are strongly dependent on the length of the...
The use of phosphazene bases in combination with water was proved to be efficient in order to obtain polysiloxane polymers from cyclic monomers. Only a few minutes are necessary to obtain polymer chains with a monomer concentration of 5% at the equilibrium. For that purpose the space which is between a rheometer's plates is the most convenient device to monitor this reaction concerning a chemical...
Carbazole-containing donor–acceptor type conjugated polymers were prepared by Sonogashira cross-coupling reaction of 3,6-diethynyl-9-hexadecylcarbazole and arylene dibromides, and the optical and electrochemical properties were extensively investigated. Copolymerization with 4,7-dibromo-2,1,3-benzothiadiazole furnished the orange-colored polymer with a charge-transfer band at 440nm in CH 2 ...
Polymethacrylate and polycondensated polymers based on chromophores containing the s-triazolo[3,4-b]-thiadiazole heterocycle were synthesized. Chromophore and polymer preparations are described. Second order NLO measurements are reported for polymers and for one functionalized chromophore. The maximum value of second harmonic generation coefficient (d 33 ) measured is 11.5pm/V at incident...
A novel fluorene-based copolymer P 1 with diphenyl urea as pendent group, as well as its analogous copolymer P 2 without urea group for comparison, were synthesized by Suzuki-coupling reaction, and characterized by 1 H NMR, EA, IR and GPC. The polymers were brightly blue emissive in THF, DMF, or DMSO solution. Anion titration experiments carried out in THF indicate that the...
Reaction-induced phase separation occurring by spinodal decomposition is simulated in this paper. A technique developed earlier [Alfarraj A, Nauman EB. Spinodal decomposition in ternary systems with significantly different component diffusivities. Macromolecular Theory and Simulations, 2007;16:627–31.] that allows component diffusivities to be dramatically different has been extended to reactive conditions...
A three-dimensional simulation is carried out in the growth process of a polymer spherulite and the Hv light scattering intensity is calculated. In the simulation, a crystallite is represented by a thin disk with the optical axis perpendicular to the disk. In a growth step, each crystallite generates new crystallites, the optical axes of which are fluctuated. The simulation results reproduce prominent...
This review presents an overview of 1→2 branched dendrimers and dendrons, created by a divergent procedure, from their synthesis to modern day applications. The first members of this branched class of fractal macromolecules were prepared through a cascade synthesis, which was later replaced by the iterative divergent synthetic approach. Most classes of this 1→2 N-, Aryl-, C-, Si-, and P-branched families...
Polyaniline (PANI) (emeraldine) base has been exposed to iodine in an ethanol–water suspension. The conductivity of PANI increased from 10 −9 Scm −1 to 10 −4 Scm −1 already at the molar ratio [I 2 ]/[PANI]=1, and a higher content of iodine had only a marginal effect. This is the result of the protonation of PANI base with hydriodic acid, which is a by-product...
The composites (iPP/CNTs) made of isotactic polypropylene (iPP) and multi-wall carbon nanotubes (CNTs) were prepared by solution blending. To improve compatibility between CNTs and iPP and to enhance dispersion of CNTs in iPP matrix, CNTs were chemically modified by grafting alkyl chains. The chemically modified CNTs had about 6wt% grafted alkyl chains. Rheological measurements indicated that CNTs...
A tertiary amine functionalized 4-nitro-4′-alkoxy azobenzene mesogen with a 10 or 12 carbon spacer (azo-nN) was synthesized and complexed in equimolar proportions with poly(acrylic acid) (PA–H) and poly(sulfonic acid) (PSS–H), and investigated by thermogravimetric analysis, differential scanning calorimetry, polarizing optical microscopy, Fourier transform infrared spectroscopy and X-ray diffraction...
Norbornene polymerization and ethylene/norbornene copolymerization were studied using constrained geometry complexes 2-(tetramethylcyclopentadienyl)-4,6-di-tert-butylphenoxytitanium dichloride (1), 2-(tetramethylcyclopentadienyl)-6-tert-butylphenoxytitanium dichloride (2), and 2-(tetramethylcyclopentadienyl)-6-phenylphenoxytitanium dichloride (3) as catalysts with Al i Bu 3 and Ph...
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