The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Toluene self-diffusion coefficients in solutions of linear and crosslinked polystyrene (PS) at concentrations up to 30 wt% polymer have been determined over the temperature range 143–230 K using the 1 H n.m.r. static gradient stimulated echo method. At similar polymer concentrations, the diffusion coefficient values of toluene were higher for mixtures with crosslinked PS than for solutions...
The impact strength of blends consisting of polystyrene (PS) and ethylene-propylene-diene rubber (EPDM) could be increased by adding a poly(styrene/ethylene-propylene) (SEP) compatibilizer and an organic peroxide during reactive extrusion. The increased impact strength could be related to an enhanced adhesion between the dispersed EPDM phase and the PS matrix, as a consequence of radical graftlink...
This paper deals with experimental and theoretical investigations on the compatibility of binary polymer blends in solution. The experimental phase boundary of a crystalline polymer such as poly(vinylidene fluoride) with polystyrene (an amorphous polymer) in dimethylformamide as solvent has been determined by size-exclusion chromatography at 25°C. The composition of the coexisting phases has been...
Five polystyrene-poly(dimethylsiloxane) (PS/PDMS) diblocks were synthesized by sequential anionic polymerization, and their morphologies characterized by small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). All materials are microphase-separated in toluene-cast films, and estimates of the interaction parameter χ indicate that these materials are all strongly segregated...
The coexistence curves of blends of polystyrene (PS, M w = 600 and 2.2 10 3 g mol -1 ) and poly(dimethylsiloxane) (PDMS, M w = 460, 1400, 3700 and 2.3 10 5 g mol -1 ) were determined using a specially designed refractometer. The coexistence curve of the oligomer blend PS (M w = 600)M w = 460) was of the upper critical...
A series of polybutadiene/polystyrene (PB/PS) network composites in the form of latexes were prepared via the concentrated emulsion polymerization method. The polymerization rate and the relative content of the crosslinked species were determined and compared at various polymerization temperatures, concentrations of initiator, and with vinyl-terminated PBs of different molecular weights. The mechanical...
Polystyrene microspheres ranging in diameter from 3 to 10 μm were prepared in alcoholic media by dispersion polymerization of styrene in the presence of a methacrylic acid/ethyl acrylate 1:1 statistical copolymer (Eudragit) as the stabilizer precursor. The effects of the initial Eudragit and free radical initiator concentrations on the microsphere dimensions, the microsphere size distribution and...
Physical ageing in polystyrene (PS) has been studied by means of modulated differential scanning calorimetry (m.d.s.c.). The results show that there exists a characteristic annealing temperature at which relaxation enthalpy has a maximum value. When annealing below 65 o C, another relaxation peak has been found. The position of this relaxation peak, which changes with annealing temperature,...
Transmission electron microscopy was used to study monolayers of polystyrene covalently attached to the surfaces of highly dispersed silica gels. The layers were grafted by using immobilized azo initiators and performing the polymerization reaction directly at the surface of the particles. Mono-energetic inelastically scattered electrons were used to map the silicon, oxygen and carbon distribution...
Maleic anhydride (MAH) was grafted to polystyrene (PS) by reactive extrusion in the presence of a free-radical initiator. The grafting reaction was confirmed by spectroscopic analyses. The amount of MAH grafted on PS was evaluated by a titration method. The polystyrenes functionalized with MAH (MPSs) were blended with polyamide 6 (PA6), and the effect of MAH units incorporated in PS on the compatibility...
Molecular dynamics (MD) simulations have been used to study bulk atactic polystyrene (aPS). A united-atom non-bonded potential is calibrated for the aromatic-ring carbons, which, along with previously determined non-bonded functions, results in a good representation of pressure-volume-temperature relations for aPS. Experimental X-ray scattering data for glassy aPS are well reproduced in simulation...
Blends of anionically prepared narrow-molecular-weight-distribution polystyrene (PS) and poly(cyclohexyl methacrylate) (PCHMA) of different molecular weights have been studied. The molecular weights of the PCHMA samples are in the range of two to three entanglement molecular weights M e . The phase diagram was determined by turbidimetry. The critical temperature is about 245°C. Differential...
A method is presented to evaluate the Koningsveld g-functions for quasi-ternary polymer solutions and blends, involving binary and ternary interactions. A robust set of 12 equations derived from the Flory-Huggins lattice theory, dealing with liquid-liquid phase separation conditions, have been solved using as input data the experimental volume fractions of each component in each coexisting phase...
Commercial polystyrene has been modified by chemically attaching 6-methyl-1,3,5-triazine-2,4-dione moieties to it in the para position of the aromatic rings. Chlorination of this novel polymer in aqueous base yielded poly(1,3,5-trichloro-6-methyl-6-(4 -vinylphenyl)-1,3,5-triazine-2,4-dione) which functioned as a biocide against the bacterium Staphylococcus aureas in a water-filter application. ...
Core-shell particles were prepared in which crosslinked polystyrene formed the core and the shells were of poly(styrene-g-N-isopropylacrylamide). The particles were successfully prepared by copolymerizing styrene with an N-isopropylacrylamide macromonomer in the presence of crosslinked polystyrene latices. Two series of core-shell particles have been prepared. In the first series the core and shell...
The styrene-glycidyl methacrylate (SG) copolymer can be used to compatibilize the immiscible and incompatible blends between polystyrene (PS) and liquid crystalline polymer (LCP) copolyester. The epoxy functional groups present in the SG copolymer can react with the carboxylic and/or the hydroxyl terminal groups of the LCP at interface to form the SG-g-LCP copolymer during melt processing. This...
The critical dynamics of a low molecular weight binary polymer blend of polystyrene and polyisoprene is studied near the critical point by dynamic light scattering. Fast and slow modes are observed in the polarized mode in accordance with previous experiments in similar low molecules weight binary polymer blend melts. A new mode is detected in the depolarized dynamic light scattering experiment...
The drawing and orientation-relaxation behaviour of monodisperse linear and 3-arm star polystyrenes was studied as functions of temperature, strain-rate and relaxation-time. Differences in birefringence were found for linear and star polymer, with the same span molecular weight (M s ), drawn to large strains above the glass transition temperature (T g ) for time-scales close to, or...
The spin-label method has been used to study the structure and molecular motion of polystyrene chains adsorbed on porous silica. Spin-labelled polystyrene (PS) with a narrow molecular weight distribution, havingM w (weight average molecular weight) = 1.9 10 5 was adsorbed on the surface of porous silica with two different pore diameters, 28.5 nm (MB-300) and 81.3 nm (MB-800), in...
A miscible PS/PPO blend was prepared and its miscibility was confirmed by d.s.c. It was found that the miscibility of polymer blends could be evaluated by the measurement of their thermal diffusivity. The conductivity in the liquid state was smaller than that estimated from a linear-relation with the PPO content, but in the solid state, the conductivity was larger than the estimated value. This...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.