Structural morphology of poly(styrene)-poly(butyl acrylate) polymer-polymer composites studied by dynamic mechanical measurements

Cavaillé, J.Y.; Vassoille, R.; Thollet, G.; Ríos, Leonardo; Pichot, Christian

doi:10.1007/bf00665498

Cited by 39 publications

(29 citation statements)

References 18 publications

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“…In addition, some years ago, [3] we showed that a drastic reinforcing effect may be observed, but also that this effect is closely dependent on the material processing step. For this reason, a part of the present investigations has been focused on the effect of particles percolation, especially when they are much stiffer than the matrix.…”

Section: Introductionmentioning

confidence: 99%

Polymer Based Nanocomposites: Effect of Filler-Filler and Filler-Matrix Interactions

et al. 2001

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Nanocomposite materials present specific features, mainly due to their very high interfacial area, and a very short distance between reinforcing particles surface. For polymer based nanocomposites, reinforcing particles are most of the time much stiffer than the matrix. In that case, the percolation of those particles which occurs at a threshold fraction which depends on their shape factor (and on their dispersion characteristics) is shown to play a drastic role, especially if they form a rigid network. Such a network may result from strong interactions between the surface of the dispersed particles, but softer network may appear if the particles are bound together through the interactions of their surface with polymer chains. In order to analyze and to predict the behavior of nanocomposite materials, a modeling of this type of interactions is proposed, and allows to better understand the origin of the high reinforcing effect, generally observed. However, the complete prediction of composite materials with percolating dispersed fillers is still a difficult problem and requires further developments. It exemplifies for the special case of composites a general problem of two phase materials: the effect of scaling down the reinforcement and the properties of entangled structures.

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Section: Introductionmentioning

confidence: 99%

Polymer Based Nanocomposites: Effect of Filler-Filler and Filler-Matrix Interactions

et al. 2001

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“…The mechanical detection of the second phase after thermal treatment arises from an increase of PVA domain size or degree of connectivity within the PVA phase. An analogous phase rearrangement has been observed for films obtained from PS-PBA core-shell particles or homopolymer blends, upon annealing at a temperature higher than the glass transition temperature for PS (32,33). It has been attributed to a more or less extended coalescence of the PS phase at high temperature.…”

Section: Sterically-stabilized Particlesmentioning

confidence: 69%

Dynamic Viscoelastic Properties of Polymer Latex Films

Richard¹

1996

ACS Symposium Series

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The linear viscoelastic behavior of latex films is studied using Dynamic Micromechanical Analysis (DMA). Dried latex films are considered as cellular structures. The core of the cells consists of the hydrophobic particle core, whereas the array of interfacial membranes arise from the hydrophilic shells of the particles which provide colloidal stability in the initial dispersions. Both cases of electrostatically-and sterically-stabilized particles are considered. For the former latex particles which bear copolymerized carboxylic species at their surface, the influence of the cross-linking density within the particle cores is investigated, together with the modification of interfacial membranes induced by H bonding or ionic interactions. The viscoelastic behavior is correlated with the structure of the films which is determined by Small Angle Neutron Scattering (SANS) experiments and Transmission Electron Microscopy (TEM). Segment diffusion coefficients can be deduced from DMA spectra and make it possible to predict membrane preservation or further coalescence. The viscoelastic properties of films obtained from the latter latex particles which bear a steric stabilizer partly grafted in their shell, are also studied. The effect of thermal annealing of the films is more particularly investigated. A specific rebuilding effect of the membranes upon annealing is evidenced for this kind of film and the influence of various parameters (particle size, volume fractions, features of polymer shell) is semi-quantitatively investigated using an equivalent mechanical model and the Kerner equation.Latexes consist of water dispersed polymer particles currently prepared by the well controlled emulsion polymerization technique.

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“…CavaillC et al 27 have investigated the preparation of PS/PBA heterogeneous particles, and they reported that PBA formed domains that did not surround the PS seed particles. The second-stage polymerization was conducted at 70°C.…”

Section: Preparation and Modification Of Core-shell Particlesmentioning

confidence: 98%

Water‐based radiation‐curable latexes

Odeberg¹,

Rassing²,

Jönsson

et al. 1996

J of Applied Polymer Sci

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and 'Hoechst-Perstorp AB, S-284 80 Perstorp, Sweden SYNOPSISFilm-forming polystyrene/poly(n-butyl acrylate-co-glycidyl methacrylate) [PS/P(BA-co-GMA)] core-shell latex particles were prepared via a two-stage emulsion polymerization procedure using a polystyrene latex seed. Delayed addition of GMA was used in order to locate functional epoxy groups close to the particle surfaces. It was found t h a t a temperature of 25°C a t the second-stage polymerization, in combination with a redox initiator system, was essential for the formation of' a uniform shell of BA-GMA copolymer around the PS core. T h e latex particle morphology was investigated by transmission electron microscopy (TEM). Reactive double bonds were introduced into the particle shells in order t o produce a film-forming latex system t h a t could be cured by ultraviolet (UV)-radiation without any need t o use reactive multifunctional monomers or oligomers as crosslinkers. T h e surface-bound epoxy groups were used as grafting sites for amine or carboxyl functional unsaturated monomers, respectively. T h e grafting was demonstrated by Fourier transform infrared (FTIR) spectroscopy. Films prepared from modified and unmodified latexes were exposed to UV radiation in the presence of a photoinitiator. Crosslinking was tested by thermal mechanical analysis (TMA) and by determination of swelling a n d gel content of exposed films. It was demonstrated t h a t films from the modified latexes after irradiation had significantly higher stiffness and gel content and showed lower swelling than unmodified ones. INTRODUCTIONThe mechanical properties of a coating material can be improved by crosslinking the binder after film formation, e.g., by radiation curing. The simplified mechanism for radiation curing involves formation of free radicals, which react with double bonds present in the film to form propagating species. If more than one double bond is present per molecule, a cross-linked network develops.A conventional radiation-curing coating system generally consists of a liquid reactive prepolymer, different monomers, a photoinitiator ( UV-curing systems), pigments, and various additives.' In a water-based coating system, the reactive polymeric binder may be dissolved or dispersed in water. In the latter case, the binder may be prepared by emulsion polymerization.* To whom all correspondence should be addressed As compared to organic-based coating systems, water-based systems have the advantage of low emission of organic compounds to the atmoDifferent radiation-curing water-borne coatings have been reported, e.g., w a t e r -~o l u b l e ,~ water-thinnable,' water-dispersible, and latexbased' systems. Some of these systems contain multifunctional acrylates. The main disadvantage of water-based UV curable coatings are essentially the same as for conventional water-borne coatings, i.e., the need to evaporate water before UV curing. ' Reduction of the amount of polluting solvents and monomers in radiation curable coatings may be achieved by incorporating the functi...

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Structural morphology of poly(styrene)-poly(butyl acrylate) polymer-polymer composites studied by dynamic mechanical measurements

Cited by 39 publications

References 18 publications

Polymer Based Nanocomposites: Effect of Filler-Filler and Filler-Matrix Interactions

Polymer Based Nanocomposites: Effect of Filler-Filler and Filler-Matrix Interactions

Dynamic Viscoelastic Properties of Polymer Latex Films

Water‐based radiation‐curable latexes

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