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The crystallinity of linear low-density polyethylene (LLDPE) after electron beam irradiation and subsequent grafting with acrylamide in aqueous solution was investigated by differential scanning calorimetry and X-ray diffraction. The LLDPE was pre-irradiated in air or argon in the dose range up to 20 Mrad. The pre-irradiation atmosphere influences the grafting kinetics due to differences in the...
Homopolymers and random copolymers derived from 3-vinylpyridium salts form compact coils in aqueous solutions. The resulting hydrophobic microdomains were characterized by both the hypsochromic shift of the wavelength emission band and the fluorescence quantum yield increase of a molecular rotor used as a fluorescence probe.
The effect of molecular weight between crosslinks, M c , on the fracture toughness and fracture behaviour of diallylterephthalate resin was investigated. As M c increased, the fracture toughness increased rapidly up to a maximum value and then decreased gradually. Scanning electron micrographs showed that the fracture toughness increased with an increase in the length of the slow...
Dissolution of polystyrene-block-poly(ethylene-co-propylene) (PS-PEP) in decane, a selective solvent for the PEP block, and dioxane, a selective solvent for the PS block, at room temperature leads to formation of metastable micellar structures, which convert into stable micelles with molar mass reduced several times after heating above 50°C. By comparing small-angle X-ray scattering (SAXS) and...
Statistical copolymerization has been performed for five binary systems using 1-methoxy-2-methyl-1-trimethylsilyloxy propene (initiator) and tetrabutylammonium bibenzoate (catalyst) in tetrahydrofuran solution. The copolymer compositions were determined by elemental analysis for nitrogen and the results evaluated by the Kelen-Tudos method. The monomer pairs concerned are (1) acrylonitrile (AN) and...
A method was developed to prepare a crystalline structure of β-TiCl 3 (brown) using an electron-donor compound as an internal Lewis base, namely, diisoamyl ether (DIAE). β-TiCl 3 combined with triethylaluminium (TEA) resulted in highly active and stereospecific catalyst systems close to those based on violet TiCl 3 (α-, γ- or δ-TiCl 3 ) for propylene polymerization...
New siloxanes with acid-sensitive substituents have been synthesized by means of hydrosilylation, starting from methylhydrosiloxanes. Details of the preparation and characterization are reported. p-t-Butoxycarbonyloxystyrene,p -t-butoxystyrene and t-butyl methacrylate turned out to be excellent reagents in these experiments. 1 H, 13 C and 29 Si nuclear magnetic resonance...
Small-angle X-ray scattering (SAXS) has been applied in obtaining the solution parameters (molecular massM , radius of gyration R g , radius of gyration of cross-section R q , mass per unit lengthM u , and persistence length a * ) of a poly(acrylic acid) (PAA) sample in dioxane at 25°C. The M and R g values measured from SAXS were 552 000 Da (daltons) and 292...
The statistical terpolymer composed of 52 mol% vinylidene fluoride (VDF), 36 mol% tetrafluoroethylene (TFE) and 12 mol% hexafluoropropylene (HFP) is a ductile material that can be highly deformed in uniaxial tensile tests. Wide-angle and small-angle X-ray scattering (WAXS, SAXS) techniques have been used to study the structure of uniaxially oriented samples. WAXS shows that the terpolymer exhibits...
The normal modes and their dispersions for isotactic poly(4-methyl-1-pentene) have been obtained in the reduced zone scheme using Wilson's GF matrix method as modified by Higgs. The zone centre frequencies and Urey-Bradley potential field have been obtained by fitting the observed Fourier transform infra-red absorption bands. Some of the characteristic features of the dispersion curves are repulsion,...
4-(N,N-Diallylamino)pyridine (DAAP) and N,N-diallylaminobenzene (DAAB), each having only a single diallylamino group, and N,N,N ,N -tetrallyl-4,4 -diaminobenzidine (AAB), N,N,N ,N -diaminodiphenyl-suflone (AABS) and N,N,N ,N -tetrallyl-4,4 -diaminodiphenyl ether (AABE), each of which has two diallylamino groups, were prepared by means of N-alkylation reaction involving aromatic amines and...
Faucher investigated the stress relaxation behaviour of isotactic polypropylene at temperatures between -67 and 140°C and found that a master curve could be formed by applying the principles for thermorheologically simple (TRS) materials. Since a previous investigation by the authors has shown that the TRS principle fails to model the viscoelastic performance of isotactic polypropylene consistently,...
Fourier transform (FT)-Raman and infra-red (i.r.) spectroscopy were utilized to monitor changes in the morphology of a commercial, phase-segregated thermoplastic polyurethane (TPU) as a function of LiClO 4 concentration (0.1 to 2.0 mmol/g TPU). Significant changes in both the FT-Raman and the FTi.r. spectra were detected which suggest a competition between hydrogen bonding and lithium cation...
Polypyrrole-polypropylene conducting polymer composite films with good mechanical properties and high electrical conductivity were prepared using a two-direction permeation/diffusion polymerization method. The oxidant used was iron(III) chloride. Polypropylene microporous films prepared by the biaxial stretching technique were used as the matrix material. The maximum conductivity of these composite...
The network structures formed when the diglycidyl ether of bisphenol A is cured with two stoichiometries of diaminodiphenyl sulfone have been studied by solid-state 13 C n.m.r. at temperatures well above the glass transition temperature. High-resolution spectra have been obtained giving detailed information on the chemistry of these structures. Spectral editing and two-dimensional techniques...
1 3 C nuclear magnetic resonance spin-lattice relaxation times (T 1 ) and nuclear Overhauser enhancement factors 13 C{ 1 H} (NOEf) have been measured on solutions of poly(ethylene terephthalate) (PET), poly(ethylene isophthalate) (PEI) and poly(ethylene isophthalate-co-terephthalate) (PEIT) in d 2 -tetrachloroethane. TheT 1 and NOEf values are...
The dipole moment has been measured for various stereostructural forms of poly(N-vinylcarbazole) (PVK) in solution in 1,4-dioxane and in toluene in the temperature range 288-338 K. The dielectric and dipole moment data were correlated with the stereostructure of PVK. The dipole moment behaviour of various types of PVK, prepared using different catalyst systems, may be explained in terms of 3, 2...
Melt blends of poly(methyl methacrylate) (PMMA) with a phenoxy (polyhydroxy ether of bisphenol A) have been prepared over the complete composition range using a single-screw extruder. Injection-moulded specimens of the blends were transparent, and differential scanning calorimetry and rheological measurements gave a single glass transition temperature (T g ), indicating miscibility of the...
Due to their poor solubility in organic solvents, triazine-based polyamines are very difficult to characterize with respect to chemical structure and molar mass. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is shown to be a unique method for investigating both the reaction between substituted 2,4-dichloro-s-triazines and diamines, and the chemical structure of the reaction...
The graft copolymer of acrylic acid on biopolymer chitin, with 45% grafting efficiency, was used to study the effect of the carboxylic group of the graft copolymer on the metal binding ability of calcium ions in aqueous solution as a function of pH, contact time and metal concentration. The adsorption equilibrium data correlate well with the Langmuir isotherm equation. The maximum adsorption capacities...
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