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The comonomer sequence distribution of a propylene-ethylene random copolymer has been investigated by a combination of temperature rising elution fractionation, 13 C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry (d.s.c.). The propylene-ethylene copolymer exhibited a wide range of comonomer compositional heterogeneity...
We have studied morphological development with time under controlled shear condition for 7525 wt/wt poly(butylene terephthalate) (PBT) and polystyrene (PS) blend having various amounts of poly(styrene-ran-glycidyl methacrylate) (PS-GMA) as an in situ compatibilizer prepared by solution blending method. The morphology of the blend without PS-GMA develops via a coarsening process during an annealing...
The photo-oxidative degradation study of nylon 66 was carried out in a polychromatic irradiation chamber (Sepap 12/24, λ =< 290 nm) at 60 o C in air. The extent of photo-oxidation was monitored by Fourier transform infrared spectrometry. The sample underwent extensive changes in hydroxyl, carbonyl and amorphous region of infrared upon irradiations. The photo-products were characterized...
Morphological investigations for hybrid materials composed of phenolic resin and silica, prepared by in situ polymerization of silicon alkoxide, were performed using TEM. Irregularly shaped silica particles a few tens of nanometres in size, composed of hyper-fine particles, are homogeneously dispersed in the transparent hybrid materials forming a partial or uniform silica network depending on the...
A simple and semiempirical rheological equation of state was developed to describe and predict the steady-state shear viscosities of hollow sphere loaded polymer melts as functions of temperature, shear rate, and composition of hollow sphere. High density polyethylene (HDPE) was used as a matrix polymer and steady-state shear viscosities of various compositions of HDPE/hollow sphere polymeric composites...
Interactions in binary polymer systems have been analysed from the viscosity behaviour. Dilute solution viscosity measurements were made on three different ternary polymer (1)/polymer (2)-solvent (3) systems, i.e. acrylonitrile-butadiene rubber (NBR)/polystyrene, NBR/poly(styrene-co-acrylonitrile), NBR/poly(acrylonitrile-co-butadiene-styrene) in chloroform, as a function of blend composition. The...
Hybrid materials of poly(ethylene oxide-co-epichlorhydrin), HYDRIN, and silica were prepared by a sol-gel process. An inorganic network was grown in a tetrahydrofuran/organic polymer solution from acid hydrolysis and polycondensation of tetraethoxysilane, TEOS. During solvent evaporation and simultaneous growth of the inorganic network, phase separation was observed. The mechanism of phase separation...
Thermoplastic elastomers consisting of triblock copolymers (MBM) with outer syndiotactic poly(methyl methacrylate) (sPMMA) blocks associated to an inner polybutadiene (PBD) block have been modified by stereocomplexation with isotactic PMMA (iPMMA) at a constant 21 sPMMAiPMMA (or si) mixing ratio. Toluene cast films of these stereocomplexes have been studied by thermal analysis as a function of molecular...
Mechanical properties of poly(phenylene sulfide)(PPS)/poly(ethylene-stat-glycidyl methacrylate)-graft-poly-(acrylonitrile-stat-styrene)(EGMA) blends at various testing temperatures (-50 o C, 25 o C and 150 o C) and EGMA contents (0, 2, 5, 10 and 20 wt.%) were investigated. Also the tensile and impact fractured surface and inner subsurface microstructures were investigated...
Methylcelluloses are widely used for industrial purposes due to their peculiar properties. These are the consequence of associative behaviour due to hydrophobic interactions involving highly substituted units. The properties of commercial samples with heterogeneous distribution of the substituents and laboratory-made samples, with a more homogeneous distribution, are compared to allow a better understanding...
In order to obtain a new family of acrylic organotitanium polymers which could be of major interest in the field of non-toxic, self-polishing, antifouling coatings, five acrylic organotitanium monomers, three of which are new, were synthesised. They were analysed by n.m.r. and FTi.r. spectroscopy as well as by microanalysis. Their main features were studied from a structural point of view. The...
The conductivity of nitrile rubber (NBR), ethylene-proylene-diene rubber (EPDM) and 5050 NBR/EPDM blend has been measured against the loading of conductive carbon fibre to check the percolation limit for each system. The volume resistivity of all fibre-rubber composites increases with the increase in temperature, and the rate of increase in resistivity against temperature depends on the loading of...
Solvent activities were measured using a gravimetric method in the range 48-70 o C. The polymers were: 15-arm, 20-arm star and linear poly(ethylene oxide), and 8-arm star and linear polystyrene. The solvents were acetone, chloroform and cyclohexane. In the concentrated regime, to 0.5 solvent weight fraction, there is no significant effect of polymer structure on solvent activities.
The lattice Monte Carlo (MC) simulation is performed to investigate the interface between flexiblle polymers and thermotropic low molecular liquid crystals (LCs), where the anisotropic attraction between nearest neighbour rods is described by the Lebwohl-Lasher nematogen model. The simulation outputs not only confirm some previous numerical calculations under mean-field assumptions, but can reveal...
Ultra-high-molecular-weight polyethylene (UHMWPE) samples of molecular weight 6 million were compressed using a channel die and characterized by wide-angle and small-angle X-ray scattering. The results were compared to previous studies performed on high-density polyethylene (HDPE) under the same compression conditions. Most deformation mechanisms exhibited by UHMWPE were also observed in HDPE. ...
Effects of chemical composition and structure of unsaturated polyester (UP) resins on the miscibility of styrene (ST)/UP/low-profile additive (LPA) ternary systems containing thermoplastic polyurethane (PU), poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) as LPAs, at room temperature and cured sample morphology were investigated. Three series of UP resins were synthesized, which included...
A light microscope was coupled to the flat sheet die of a laboratory extruder allowing on-line morphology measurements during the extrusion of polymer blends. Polystyrene (PS)/polymethylmethacrylate (PMMA) blends were studied in the concentration range of 5-20 wt% PMMA. Image analysis of the on-line photographs allows a fast and reliable determination of the particle size distribution devoid of...
The surface composition of films prepared from blends containing different percentages of pure soluble collagen and poly(acrylic acid) or poly(sodium vinylsulfonate), was analysed by ESCA. The results indicate that the content of collagen on the surface of the blends is higher than expected, and that such enrichment is more evident for the blends containing a lower percentage of collagen.
Several types of commercial and developmental aluminoxanes were studied in the semi-batch polymerization of ethylene using bis(cyclopentadienyl) zirconium dichloride (Cp 2 ZrCl 2 ). High temperature gel permeation chromatography (GPC) measurements of polyethylene (PE) formed using various types of aluminoxanes approximated Flory's most probable distribution from a single site-type...
Isotactic polypropylene (iPP) was blended with a high-density polyethylene (HDPE) and the blends, quenched from the melt at temperatures between 170 and 200 o C, were examined by looking at surface replicas in a transmission electron microscope. Widespread phase separation was evident and a range of morphologies recorded. Phase ripening takes place progressively with time as the blends are...
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