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The mechanical properties and fracture behaviour of polyurethanes with two hardness levels have been measured. The polyurethanes were based on polytetramethylene ether glycol (PTMEG) and toluene diisocyanate (TDI) and two different curatives, or chain extenders - methylene-bis-orthochloroaniline (MBOCA) and dimethylthiotoluene diamine (Ethacure E300). The polyurethanes made using MBOCA as the curative...
Temperature dependent X-ray diffraction studies of poly(di-n-alkylsiloxane)s substituted with side chains containing 7 to 10 carbon atoms have been carried out in order to elucidate the crystalline structure of these materials. In contrast to their lower substituted homologues, no evidence for the presence of a hexagonal columnar mesophase could be found for the investigated materials. At low temperatures,...
Polymerization of monomer-containing single-phase Winsor-IV microemulsions was studied and the morphology of the polymer obtained was found to be related to the structure of the microemulsion. The hydrophobic component of the microemulsions was formed with methyl methacrylate together with ethylene glycol dimethacrylate. Methacrylic acid was found to be effective as a polymerizable cosurfactant...
The use of resolution enhanced X-ray diffraction scans for studying small differences in the structures in poorly crystallized semicrystalline polymers is illustrated with examples from three polymers with different crystallization behaviour, namely nylon 6,6, nylon 6 and poly(chlorotrifluoro ethylene). The effects of small coherence length were deconvolved using maximum entropy methods to obtain...
Different types of conductive polymers have been synthesized within the pores of nanoporous microfiltration membranes. These membranes contain linear, cylindrical pores of varying diameter from 10 nm to 10 μm. When synthesized within these pores, the conductivity of the polymer increases compared to the conductivity of a polymer film synthesized on a planar electrode. The enhancement in conductivity...
Metal-containing polyimides with the metals in the main chain were prepared by firstly reacting pyromellitic dianhydride with a mixture of divalent metal salts of sulfanilic acid [ASA(M)] and 4,4 -diaminodiphenylmethane to form poly(amide acid) salts, the desired polyimides being obtained when the poly(amide acid) salts were separated from the solvent and heated under imidization conditions. The...
Time-resolved synchrotron small-angle X-ray scattering measurements have been performed during the heating and melting of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). A rapid, continuous rise in d-spacing was observed during melting, consistent with the disappearance of thinner, unstable crystals from stacks of lamellae possessing a broad distribution of thicknesses....
Propylene was homopolymerized with the ansa-metallocene Ph 2 C(fluorenyl)(cyclopentadienyl)ZrCl 2 /methylaluminoxane catalyst to a highly syndiotactic polymer using a constant set of parameters. The properties of the pure syndiotactic polypropylene (sPP) such as molecular weight, chain microstructure and melting point were investigated, and the morphologies of uniaxially oriented...
Dynamic viscoelastic (DVE) measurements are made on seven ovalbumin (OVA) gel samples induced by thermal denaturation of aqueous suspensions of OVA with OVA concentration C ranging from 12 to 45 wt% at 160°C for 5 min and subsequent moulding under pressure, and also on four OVA gels with higher C prepared by slow evaporation of water from the 45 wt% gel. The storage and loss shear moduli, G (ω)...
Poly(α-ethynylnaphthalene)s were prepared using [Rh(norbornadiene)Cl] 2 complex (a stereoregular polymerization catalyst) in triethylamine or alcohol, and WCl 6 (a metathesis catalyst) in toluene. 1 H nuclear magnetic resonance, electron spin resonance and laser Raman spectra of both polymers were measured in order to assign the geometrical structures with respect to the C=C...
Polyurethane (PU) ionomer acrylates and non-ionomer acrylates were synthesized from poly(propylene glycol)((PPG), isophorone diisocyanate (IPDI), dimethylolpropionic acid (DMPA), 2-hydroxyethylacrylate (HEA), and N-vinylpyrrolidone (NVP), tripropyleneglycol triacrylate (TPGDA), trimethylolpropane triacrylate (TMPTA), and were characterized in terms of water swell, mechanical, and dynamic mechanical...
Photooxidation reactions of linear polysilanes [poly(cyclohexylmethylsilylene) and poly(methylphenylsilylene)], a network polysilane [poly(hexylsilyne)] and branched polysilanes [poly(cyclohexylmethylsilylene-co-phenylsilyne) and poly(cyclohexylmethylsilylene-co-hexylsilyne)] were investigated both in solution and in the solid state in the presence of oxygen. The reactions were monitored by u.v. and...
Solution-grown crystals (SGC) of poly(l-lactide) (PLLA) were prepared from 0.01% (w/w) or 0.08% (w/w) acetonitrile solution by an isothermal crystallization method. Their morphology and structural features were examined by transmission electron microscope with the diffraction mode, wide-angle X-ray diffractometry and atomic force microscope. The molecular chains are packed in the manner perpendicular...
The microhardness of a series of random copolyesters of 4-hydroxybenzoic (HBA) and 2-hydroxy-6-naphthoic acid (HNA) has been investigated as a function of composition and temperature. The results reveal that, at room temperature, the microhardness of non-oriented materials deviates from the linear additivity of the hardness of single homopolymers. Such a deviation is shown to be mainly related to...
Structural investigations of thermally processable, conductive polyaniline (PANI) are presented. Free standing, compact films of conductive polyaniline were prepared by hot pressing of polyemeraldine previously protonated with diphenyl hydrogen phosphate (DPHP) in chlorobenzene. The samples were then subjected to wide-angle X-ray diffraction (WAXD) and small angle synchrotron radiation scattering...
A possible structural model for the mesomorphic form of syndiotactic poly(p-methylstyrene) is discussed. The structural analysis is performed through the comparison between the experimental X-ray diffraction intensities and the calculated intensities for model structures constituted by ordered and disordered aggregates of chains. This analysis provides support for the hypothesis that the mesomorphic...
The structure of freeze-dried atactic polystyrene (a-PS) prepared from dilute benzene and cyclohexane solutions was examined by using Fourier transform infra-red spectroscopy, wide-angle X-ray scattering and differential scanning calorimetry (d.s.c.). The phenyl-phenyl correlation in the freeze-dried a-PS is weak compared with that in the reference sample cast from a 5 wt% solution in tetrahydrofuran...
Polyphenylsilane, (HSiC 6 H 5 ) n , was synthesised by catalytic coupling of phenylsilane using Cp2ZrCl22BuLi as a catalyst. Chlorination of the resulting polymer with tetrachloromethane (CCl 4 ) gave polychlorophenylsilane, (ClSiC 6 H 5 ) n , subsequent substitution of chloride by dimethylamine yielded polydimethylaminophenylsilane, ((CH ...
A study was made of the structure and physico-mechanical properties of epoxy polymers obtained using different curing agent–oligomer ratios. The results were analysed within the framework of the cluster model of structure of the polymer amorphous state. It was shown that the model under consideration can be used for determining the quantitative structure–property relationships for cross-linked polymers...
Mechanical properties of poly(styrene-b-n-butylmethacrylate) diblock copolymers, PS-b-PBMA, with different lengths of the polystyrene block were investigated. The copolymers display a composition range where the tensile strength of the block copolymers exceeds the values of the corresponding homopolymers. At a PS-content of 74vol% not only the tensile strength but also the strain at break is higher...
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