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Polyethylene terephthalate (PET) was alcoholised with ethylene glycol to synthesize hydroxytelechelic oligomers of PET. On the other hand, commercial hydroxytelechelic polyϵ-caprolactone was modified in order to synthesize carboxytelechelic polyϵ-caprolactone. The chemical structure of the products was investigated by 1 H NMR. Multiblock copolyesters were then synthesized by polyesterification...
The dimensional recovery of biaxially oriented styrene–acrylonitrile (SAN) copolymer films appears to consist of two second-order kinetic processes taking place in parallel. The earlier stage of recovery is dominated by a second-order process with a higher rate constant and a lower activation energy. The later stage process has a lower rate constant but with a higher activation energy. In the earlier...
A study has been made of the inhibitory effects of diphenylpicrylhydrazyl and certain nitroxides upon systems at 60 °C involving benzoyl peroxide with methyl methacrylate, styrene or acrylonitrile. The pattern of results is rather different from that found in corresponding experiments with azobisisobutyronitrile as the source of radicals. When using the peroxide, relationship between duration of inhibition...
PVA/WO 3 hybrids were produced by using ion exchange process of Na 2 WO 4 ·2H 2 O. Microstructures of this hybrid was estimated by SAXS measurement as follows; the WO 3 rich domains having radius of gyration of about 5.7 nm (estimated in Guinier regime), in which PVA chains were partly incorporated, were dispersed evenly in PVA matrix with the correlation length...
The evaluation of the size-exclusion chromatography (SEC) concentration elution curves by means of a calibration dependence obtained in a given SEC set for a polymer different from the polymer to be analyzed results in an error in the determination of both molecular weight and molecular-weight distribution (MWD). The problem is analyzed assuming the validity of the universal-calibration concept. The...
The macroscopic deformation behaviour of amorphous polymers is dominated by localisation phenomena like necking and crazing. Finite element simulations show that the details of the intrinsic post-yield behaviour, strain softening and strain hardening, determine the severity of strain localisations. In order to perform these numerical simulations an accurate constitutive model is required. The compressible...
Mechanical properties of miscible blends of high molecular weight poly(N-vinyl pyrrolidone) (PVP) with a short-chain, liquid poly(ethylene glycol) (PEG) of molecular weight 400 g/mol have been examined as a function of PVP–PEG composition and degree of hydration. The small-strain behavior in the linear elastic region has been evaluated with the dynamic mechanical analysis and compared with the viscoelastic...
Radical polymerization of butyl acrylate (BA) and random copolymerizations of styrene (St) and BA and St and methyl methacrylate (MMA) in the presence of 7-aza-15-hydroxydispiro[5.1.5.3]hexadecane-7-yloxyl (1) and 1-aza-2,2-dimethyl-4-hydroxyspiro[5.6]dodecane-1-yloxyl (2) were carried out. Radical polymerization of BA at 120 °C in the presence of 1 gave poly(BA) with M n =20200 and M ...
A series of polymer–clay nanocomposite (PCN) materials that consist of poly(vinyl alcohol) (PVA) and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic PVA matrix via an in situ free radical polymerization with AIBN as initiator. Organic vinyl acetate monomers are first intercalated into the interlayer regions of organophilic clay...
The AB 2 monomer, 3,5-bis(4-fluorobenzoyl)phenol was synthesized via an improved four-step scheme. It was polymerized to form the corresponding fluoride-terminated hyperbranched polymer with higher molecular weight than previously reported, as evidenced by higher glass-transition temperature (T g =159°C vs. 140–143 °C). The homopolymerization showed a bimodal molecular weight distribution...
Nylon 11/organoclay nanocomposites have been successfully prepared by melt-compounding. X-ray diffraction and transmission electron microscopy indicate the formation of the exfoliated nanocomposites at low clay concentrations (less than 4wt%) and a mixture of exfoliated and intercalated nanocomposites at higher clay contents. Thermogravimetric and dynamic mechanical analyses as well as tensile tests...
The objective of this study is to investigate the relationship between gas permeability and the chemical structure and conformational properties for copolymers of styrene and its homopolymer. The diffusion and the solubility coefficients of small gas molecules (He, H 2 , Ne, O 2 , N 2 , CH 4 , Ar, CO 2 ) in amorphous structures of poly (styrene-alt-maleic anhydride)...
In this paper, the preparation and characterization of polyaniline–polyvinyl alcohol composites is described. The polyaniline composite was synthesized by chemical polymerization of aniline in media containing polyvinyl alcohol (10%, w/w). Oxidation of aniline results in a stable water based polyaniline dispersion, which can be cast to form a mechanically robust film. The electrical conductivity of...
In order to acquire fully quantitative, high signal-to-noise 13 C NMR spectra of ethylene-1-octene copolymers in a relatively short period of time, a detailed protocol has been developed, based on the addition of an optimised amount of the relaxation agent chromium(III)triacetylacetonate and without using nuclear overhauser enhancement (NOE). Compared to classical measurements with NOE, the...
The semicrystalline structure and degree of crystallinity of fractionated crystallizing poly(methylene oxide)/(polystyrene/poly(2,6-dimethyl-1,4 phenylene ether) POM/(PS/PPE) blends have been investigated by DSC, SAXS and WAXD. The three techniques yielded highly correlated results. The degree of crystallinity of the POM phase determined by DSC (X c,DSC ) decreases with decreasing POM content...
The isothermal crystallization behaviors of poly(bisphenol A-co-decane ether) (BA-C10) at different temperatures were studied in situ by means of Fourier transform infrared spectroscopic (FT-IR) measurements. Conformational changes during the induction period were investigated in details. The results suggest that conformational changes of polymer chains always take place before the start of changes...
The solubility of poly(methyl methacrylate) in acetone, expanded by carbon dioxide, was studied at 20 °C for a variety of molecular weights and architectures. The suitability of the Gas Anti-Solvent method for fractionation of poly(methyl methacrylate) was investigated with positive results. The threshold pressure for precipitation of various monodisperse molecular weights was investigated, and the...
An in situ measurement technique that isolates the mobility of charge carriers is described and analyzed. The technique allows significant improvement over conductivity measurements to monitor changes in the physical properties and state of a material as it cures. This is essential in systems where N i , the number of charge carriers, cannot be assumed constant such as during cure of epoxies,...
In this work, we utilise ‘MesoDyn’ [J Chem Phys 99 (1993) 9202; 106 (1997) 4260] density functional simulations to study the effect of temperature and concentration on the micellar morphology of polymeric surfactants. Parameterisation strategies based upon atomistic models and experimental data are discussed. Taking the temperature dependence of interaction energy into account, the change in morphology...
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