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The photoinitiated radical polymerization of difunctional vinyl ether/maleate mixtures has been studied by real-time i.r. spectroscopy, a technique which records directly conversion vs time profiles for reactions occurring within seconds. Various factors were found to affect the polymerization kinetics, such as the photoinitiator concentration, the light intensity, the presence of oxygen and the...
An in-situ compatibilizer of poly(styrene-ran-glycidyl methacrylate) (PS-GMA) was used to study the effect of blend compositions on the morphology of two different blend systems, i.e. poly(ethylene-ran-acrylic acid) (PE-AA) and polystyrene (PS) blend, and poly(butylene terephthalate) (PBT) and PS blend. The epoxy group in PS-GMA reacted easily with the carboxylic acid group in both PE-AA and PBT,...
Several isomeric aromatic diester-diacids may appear as a result of the opening selectivity of anhydride groups towards the alcohol. 1 H n.m.r. was thus used to characterize the isomeric structure and to quantify the isomer composition. It was found that the isomer ratios quantitatively correlate with electron affinity of bridged dianhydrides and is independent of the alcohol structure used...
We present an experimental and theoretical analysis of i.r. (thermal) sintering of thermosetting resins used for stereolithography. In the experimental work an epoxy resin was chosen. The optimum mix (which was quite critical) was composed of 10 parts (by weight), 1.4 parts diethylene triamine and 0.7 parts of silica powder. Using a differential scanning calorimeter (d.s.c.) we were able to determine...
The surface morphology and molecular arrangement of a Kevlar aramid fibre (coded Fibre A, from E. I. DuPont de Nemours and Co.) were studied by atomic force microscopy (AFM). Pleats parallel to the fibre axis have been observed. At nanometre scale, the polymer chains display several different arrangements from the reported crystalline structures for the bulk polymer especially in the polymer chain...
Our previous studies have proposed occurrence of transreactions and subsequent alcoholysis reactions upon heating between the carbonate group in bisphenol-A polycarbonate (PC) and the epoxide group in tetraglycidyl-4,4 -diaminodiphenylmethane (TGDDM) with the TGDDM monomer itself as a tertiary amine auto-catalyst. In this study, solution proton/carbon-13 n.m.r. as well as solid-state carbon-13 n...
Polyindole obtained by oxidizing coupling of indole, C 8 NH 7 , was studied either in the doped or the undoped state by FTi.r., Raman and electron energy loss (EEL) spectroscopies. Interpretation of the vibrational modes was facilitated by comparison of the absorption spectra of polyindole and those of related molecules acting as standards. The change from the doped to the dedoped...
The synthesis of poly(vinyl chloride) (PVC) modified with p-aminothiophenol is described. The presence of free amino groups in the products is proven and their content measured by nuclear magnetic resonance and infrared spectroscopy, and elemental analysis. Modification degrees of up to 30% can be achieved without degradation or other side-reactions. The amino group containing polymers can be easily...
Asymmetric polysulfone and polyacrylonitrile flat sheet membranes have been produced by a simple dry-wet casting technique. Both membrane types were cast at low and high shear rate. Molecular orientation in the membranes was determined using polarized reflection i.r. spectroscopy. Gas permeation properties were examined using carbon dioxide and methane as test gases. I.r. dichroism was detected...
A new technique, based on steady state fluorescence measurements is introduced for studying swelling and dissolution of polymer discs. These discs are formed by free radical polymerization of methyl methacrylate (MMA). Pyrene (Py) was introduced as a fluorescence probe during polymerization. Swelling and dissolution of disc shape poly(methyl methacrylate) (PMMA) samples in chloroform-heptane mixtures...
The aim of this work was to establish whether the lifetime of the junction zones in the poly(vinyl alcohol)/borate gels depended on the chemical composition or concentration of the constituents. It was found that the maximum in the distribution of lifetimes was about 0.3 s and independent of the polymer, borate concentrations and of the degree of hydrolysis of the polymer. The gels changed their...
The miscibility of blends of cellulose diacetate (CDA) and poly(vinyl pyrrolidone) (PVP) was extensively studied by means of differential thermal analysis and dynamic mechanical thermal analysis, tensile test, measuring viscosity of diluted and concentrated solutions of blends in acetone-ethanol mixture and morphological observations. A single glass transition temperature is observed, which is intermediate...
Solutions of a 15-mer of poly(vinyl alcohol) in water, ethanol and a 11 (mole fraction) mixture of water and ethanol have been studied by molecular dynamics simulations. The solvent structure near the solute is analysed in terms of radial distribution functions and hydrogen bonding. Results indicate a preferential solvation by water molecules. Hydrogen-bond life time analysis shows that solvent-solute...
Methyl methacrylate (MMA)-acrylamide (AA) system was studied in radical conventionally and non-conventionally initiated polymerization reaction with respect to the bootstrap effect using the penultimate model propagation kinetics of vinyl copolymerization. For this, two different methods, the Nelder-Mead simplex method and a scanning method have been adapted for the determination of r 1 ...
A novel thermoplastic elastomer consisting of a triblock copolymer (MBM) with outer syndiotactic poly(methyl methacrylate) (sPMMA) blocks associated to an inner polybutadiene (PBD) block has been modified by stereocomplexation with isotactic PMMA (iPMMA). Solution cast films of stereocomplexes have been analysed by thermal analysis as a function of the iPMMA/sPMMA (i/s) mixing ratio and the solvent...
Two-dimensional wide-angle X-ray scattering data from oriented polymers are profile fitted by describing the intensity distribution as a product of two orthogonal functions in polar cylindrical coordinates. The parameters of the fit are used to describe the structure in terms of amorphous and crystalline orientation, crystallinity and crystallite size. The possibility of using the data to refine...
This study focuses on the effect of thermal history on the morphology of poly(vinylidene fluoride). Rheo-photoacoustic Fourier transform infra-red spectroscopy (RPA FTi.r.) was utilized to measure changes in PVDF network permeability as a function of elongation. The permeability data, in conjunction with the stress-strain response, provide insights into the morphological changes resulting from deformations...
Cyclic oligomers of tetraethyleneglycol succinate [O(CH 2 CH 2 O) 4 .CO.(CH 2 ) 2 .CO] x were prepared by a ring-chain reaction. The cyclic products were characterized in full. Cyclic oligomers with up to eight repeat units were fractionated using preparative gel permeation chromatography to give narrow molar mass fractions with polydispersities of...
A series of novel polyamides carrying NLO chromophores were synthesized and their general properties were characterized. The electrooptic properties of a couple of selected compositions were studied. These polyamides were synthesized by direct polycondensation at 100°C of 4,4 -methylenedianiline or 4,4 -oxydianiline with 4-nitro-[N,N-bis(2-carboxyethyl)]aniline or 4-[N,N-bis(2-carboxyethyl)amino]-4...
In crystalline polymer/amorphous polymer blends the crystalline component crystallizes out, however low its concentration in the blend, if the blends are left at room temperature for months/years after its preparation, provided the diffusion is permissible at room temperature. This phenomenon has been termed kinetic immiscibility in crystalline polymer/amorphous polymer blend. Blends of poly(vinylidene...
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