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The synthesis of poly-yne polymers containing transition metals inserted in the main chain has been attempted by reacting a dialkyne molecule, 4,4'-diethynylbiphenyl (or DEBP), with [PtCl 2 (dppe)] and [PdCl 2 (dppe)], the platinum- and palladium-cis square-planar di-chlorine complexes containing diphenylphosphine ethane (dppe) as bidentate ligand. The aim of this work was to obtain...
A kind of novel polyurethane/Na + -montmorillonite nanocomposites has been synthesised using modified 4,4'-di-phenymethylate diisocyanate (M-MDI), modified polyether polyol (MPP) and Na + -montmorillonite (layered clay). Here, MPP was used as a swelling agent to treat the layered clay. Experimental results indicated that with increasing the amount of layered clay, the strength and...
Electrospinning is a process by which sub-micron polymer fibers can be produced using an electrostatically driven jet of polymer solution (or polymer melt). Electrospun textiles are of interest in a wide variety of applications including semi-permeable membranes, filters, composite applications, and as scaffolding for tissue engineering. The goal of the research presented here is to demonstrate that...
The goal of this work is to develop techniques for measuring gradients in particle concentration within filled polymers, such as thermosetting polymer encapsulants. A high concentration of filler particles is added to such materials to tailor physical properties such as thermal expansion coefficient. Sedimentation and flow-induced migration of particles can produce concentration gradients that are...
Adsorption of a hydrophobically modified polyelectrolyte on hydrophobized silica surfaces in aqueous divalent salt solutions was studied using an ellipsometric technique. The results indicate three distinct stages in adsorption: a relatively short induction period, a surface accumulation region, and a plateau (quasi equilibrium) region. The induction period remains unchanged with increasing divalent...
The phase behaviour of the binary copolymer systems SMA-SAN and SAN-SAN can be described well using the copolymer repulsion model. However, the phase behaviour of the ternary system consisting of SMA-SAN(1)-SAN(2) with SAN(1) and SAN(2) having different chemical compositions is not known. In order to reveal this, the composition of the blends, the composition of the SMA (ranging from 22 to 34wt% MA)...
Crystals , grown from solution, of the monodisperse 5-amide nylon 6 oligomer (4.6nm long) have been investigated using X-ray diffraction and electron microscopy. If the crystals are prepared by adding the miscible non-solvent 1,4 dioxane to a solution in trifluoroethanol the usual nylon 6 monoclinic α-structure occurs, i.e. a structure where the hydrogen-bonded sheets shear in an alternating fashion...
Molecular dynamics (MD) simulations of cis-1,4-polybutadiene in bulk amorphous state were performed to elucidate the origin of a fast relaxation process observed by quasielastic neutron scattering (QENS) measurements. The details of the torsional motion for each dihedral angle were investigated with the torsional auto- and cross-correlation functions for several temperatures in this study. Temperature...
Macroporous chitosan beads used for the immobilization of an anti-inflammatory drug were prepared by the wet phase-inversion method. There are two stages of phase-inversion observed from the cast of chitosan droplet in tripolyphosphate (TPP) aqueous solution. The first stage of phase-inversion is dominated by liquid-liquid demixing and the morphology of the freeze-dried chitosan bead shows a bundle-like...
Plastic injection molding machine that can be classified as reciprocating extruders are among the most widely used machines in industry. However, most studies in the injector design were based on steady state models developed for extruders that involved no reciprocation. This over-simplified model leaves out the most important aspect of reciprocation. The authors of this paper have derived a transient...
We analyze the crystallization process of mixtures of long and short oligomers such as n-alkanes using a Sadler-Gilmer-type growth algorithm. The short chains are assumed to crystallize only in a fully stretched conformation, while the long chains take a pathway over a folded state. Increasing the concentration of long chains from zero to unity, the zero-growth temperature, which separates the stable...
In this paper, solid blends of HPC/PVP obtained by polymerization in situ of NVP are analyzed. These blends retain the initial organization of HPC in NVP in terms of liquid crystalline structure and banded texture. It is also demonstrated that the banded texture may be stabilized with respect to thermal cycles by crosslinking the samples.
In this report, we describe an improved thermal fractionation technique used to characterize the polydispersity of crystalline ethylene sequence length (CESL) of ethylene/α-olefin copolymers. After stepwise isothermal crystallization, the crystalline ethylene sequences are sorted into groups by their lengths. The CESLs are estimated using melting points of known hydrocarbons. The content of each group...
Biodegradable aliphatic poly(butylene succinate-co- -caprolactone) (PBSCs) were synthesized through a polycondensation with titanium tetraisoproxide (TTP), diphenylphosphinic acid (DPPA) and stannous octoate (Sn(Oct) 2 ) as the novel co-catalysts. By means of gel permeation chromatography (GPC) and nuclear magnetic resonance spectrometer (NMR), it was revealed that the PBSC copolyesters had...
Molecular dynamics (MD) calculations of cis-1,4-polybutadiene in bulk amorphous phase were performed under constant pressure and constant temperature conditions. The static and dynamic properties were evaluated from the results of MD calculations. The obtained density and coefficient of thermal expansion are in good agreement with experimental data. The feature of the calculated static structure factor...
Novel microporous membranes with pore size ranging from 2 to 25nm were produced from immiscible polypropylene blends via melt processing and post-extrusion treatments. Systems containing polystyrene and polyethylene terephthalate as the minor phase components were employed as starting membrane materials at concentrations not exceeding 15wt%. The blends were first compounded in a co-rotating twin-screw...
The equivalent inclusion method (EIM) assuming linear elasticity is used to calculate the mechanical interactions between spherical rubber particles in an amorphous matrix, as in a rubber toughened polymer. The influences of the various calculation parameters are examined and it is shown that the method can provide reliable results with regard to the level of hydrostatic stress in the particles. Damage...
In this work, a methodology has been developed for construction of atomistic models of crosslinked polymer networks. The methodology has been applied to low molecular weight water soluble epoxy resins crosslinked with different curing agents that are being considered for use as a primer coating on steel. The simulations allowed the crosslink density and the amount of free crosslinking sites in the...
Isotactic polypropylene and ethylene-1-hexene copolymers containing 32 and 57mol% of 1-hexene copolymers blends (i-PP/EH32 and i-PP/EH57) were prepared by solution blending, precipitating followed by drying and hot pressing. The two blends were subject to investigation on structure and mechanical properties of these blends under uniaxial drawing. The i-PP/EH32 and i-PP/EH57 represented the immiscible...
New fluoroalkyl end-capped fullerene cooligomers were prepared by the reactions of fluoroalkanoyl peroxides with fullerene and comonomers such as acryloylmorpholine, N,N-dimethylacrylamide and acrylic acid. These fluorinated fullerene cooligomers were easily soluble in water and common organic solvents, and were able to reduce the surface tensions of both water and benzene, quite effectively. Additionally,...
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