Polypropylene/Silicate Composites on the Basis of Crazed Polymer and Hyperbranched Polyethoxysiloxane

Трофимчук, Е. С.; Nesterova, E. A.; Meshkov, I. B.; Никонорова, Н. И.; Muzafarov, А. М.; Bakeev, N.P.

doi:10.1021/ma071379d

Cited by 17 publications

(6 citation statements)

References 7 publications

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“…() conditions were found under which the deformation of amorphous glassy and crystalline polymers in liquid media occurs through the crazing mechanism and gives rise to the formation of nanoporous materials with a porosity as high as 40–60%. It is of particular interest that polymer deformation in solutions of various low‐ or high‐molecular‐mass compounds is accompanied by their penetration into the nanoporous structure of crazes to result in the formation of nanocomposites and highly dispersed polymer–polymer blends (Trofimchuk & Yablokova, ; Trofimchuk et al ., , b, ; Rukhlya et al ., ; Gruzd et al ., ).…”

Section: Introductionmentioning

confidence: 99%

Atomic force microscopic study of the structure of high‐density polyethylene deformed in liquid medium by crazing mechanism

Bagrov

Yarysheva

Rukhlya

et al. 2013

Journal of Microscopy

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SummaryA procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of highdensity polyethylene (HDPE) deformed in an adsorption-active liquid medium (AALM) by the crazing mechanism. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing deformed films from shrinkage. Deformation of HDPE in AALM has been shown to proceed through the delocalized crazing mechanism and result in the development of a fibrillar-porous structure. The structural parameters of the crazed polymer have been determined. The obtained AFM images demonstrate a nanosized nonuniformity of the deformation and enable one to observe the structural rearrangements that take place in the deformed polymer after removal of the liquid medium and stress relaxation. A structural similarity has been revealed between HDPE deformed in the AALM and hard elastic polymers.

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Section: Introductionmentioning

confidence: 99%

Atomic force microscopic study of the structure of high‐density polyethylene deformed in liquid medium by crazing mechanism

Bagrov

Yarysheva

Rukhlya

et al. 2013

Journal of Microscopy

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“…Previously, a method was developed for the incorporation of an SiO 2 phase into polymer films and the creation of polymer–silica nanocomposites using the crazing mechanism. In this work, a liquid precursor, hyperbranched polyethoxysiloxane (HPEOS), [45] and its isopropanol solutions with different concentrations were loaded into the pores of the polymer by impregnation.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we have developed an approach for the preparation of polymer–silica nanocomposites with the use of crazing for the volume filling of matrices with liquid precursors (tetraethoxysilane, hyperbranched polyethoxysiloxane, etc. ), the hydrolytic condensation of which in the presence of acidic or basic catalysts gives rise to the formation of SiO 2 directly in nanopores . The structure of such polypropylene–silica composites varies depending on the content of the inorganic component from discrete silica nanoparticles (less than 15 wt% SiO 2 ) to interpenetrating networks of a polymeric matrix and a 3D silica framework (more than 25 wt% SiO 2 ) .…”

Section: Introductionmentioning

confidence: 99%

Polyethylene–Silica Nanocomposites with the Structure of Semi‐Interpenetrating Networks

Трофимчук

Meshkov

Kandlina

et al. 2019

Macro Materials & Eng

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Organic–inorganic nanocomposites with the structure of interpenetrating or semi‐interpenetrating networks are considered as advanced materials, since they have improved thermal and mechanical properties. An alternative approach to the preparation of such hybrid systems is proposed. It is based on the synthesis of silica from the precursor of hyperbranched polyethoxysiloxane by the hydrolytic condensation reaction in the volume of pores of a polymer matrix (bulk porosity is 40 vol%) stretched via the environmental crazing mechanism. Polyethylene–silica nanocomposites with the structure of semi‐interpenetrating networks when the content of silica is not less than 20–25 wt% are obtained. These composites can undergo an additional phase separation at a temperature of 160 °C (above the melting point of polyethylene), which is accompanied by an increase in the size of the polymer phase with the formation of macrophases. At the same time, the environment (orthophosphoric acid), in which the composite is heated, fills the pores that have appeared. As a result, the content of the third component with the new functionality increases up to 50 wt%, which allowed us to impart proton‐conducting properties to the composite material and preserve its shape stability.

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“…In this work, we propose to use the solvent-crazing process − to reduce the PLA fragility and to increase its strength characteristics. Crazing of polymers is a fundamental mechanism of plastic deformation of solid amorphous and semicrystalline polymers, and it is accompanied by the formation of an oriented highly dispersed fibrillar–porous structure in local deformation zones, which are referred to as crazes. , Moreover, it is known − that crazing is considered as a method for loading polymer matrices with different thermodynamically incompatible low- and high-molecular additives, such as dyes, fire-retardant agents, odorants, bactericides, and so forth, with a simultaneous dispersion of fillers up to the nanometric level.…”

Section: Introductionmentioning

confidence: 99%

Cold Crystallization of Glassy Polylactide during Solvent Crazing

Трофимчук

Efimov

Grokhovskaya

et al. 2017

ACS Appl. Mater. Interfaces

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Uniaxial tension accompanied by the orientation and crystallization of polymer chains is one of the powerful methods for the improvement of mechanical properties. Crystallization of amorphous isotropic polylactide (PLA) at room temperature is studied for the first time during the drawing of films in the presence of liquid adsorption-active media (ethanol, water-ethanol mixtures, and n-heptane) by the solvent crazing mechanism. The crystalline structure arises only under simultaneous actions of a liquid medium and a tensile stress and does not depend on the nature of the environment. The degree of polymer crystallinity increases nearly linearly with the growth in the fraction of the fibrillar material and reaches a maximum value of 42-45%. It has been stated that polymer crystallization happens in crazes involving nanofibrils with a diameter of about 10-20 nm without affecting the bulk polymer parts. Wide-angle X-ray scattering has been used to confirm that the crazing-induced crystallization is accompanied by the formation of the α'-crystalline phase with crystallite sizes (X-ray coherent scattering region) of 3-5 nm, depending on the nature of the liquid medium. After stretching in liquid media to a high tensile strain, the strength of a PLA film has increased to 200 MPa.

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Polypropylene/Silicate Composites on the Basis of Crazed Polymer and Hyperbranched Polyethoxysiloxane

Cited by 17 publications

References 7 publications

Atomic force microscopic study of the structure of high‐density polyethylene deformed in liquid medium by crazing mechanism

Atomic force microscopic study of the structure of high‐density polyethylene deformed in liquid medium by crazing mechanism

Polyethylene–Silica Nanocomposites with the Structure of Semi‐Interpenetrating Networks

Cold Crystallization of Glassy Polylactide during Solvent Crazing

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