Yu. N. Smirnov

Effect of gamma radiation on the molecular-topological structure and properties of poly(vinylidene fluoride) and the matrix in a PVDF-based glass-reinforced plastic

The amorphous-topological structure of poly(vinylidene fluoride) (PVDF), the pseudo-network structure of which is formed by polyassociative entities of the cluster type and persists upon γ-irradiation up to 250 kGy, has been investigated. As a result of the processes involved in the fabrication of the glass-reinforced plastic (GRP), five crystalline modifications arise in the polymer matrix instead of cluster branching points in the initial PVDF, and the temperature of the molecular flow of the polymer matrix in the GRP rises from 410 to 593 K in comparison with the initial PVDF. The strength of GRP made of untreated glass cloth (110 MPa) is higher than that of the initial PVDF (86 MPa). However, when using glass cloth treated with a process sizing agent, the strength of the GRP increases up to 286 MPa. After γ-irradiation of the latter, upon which a sharp drop in the strength is observed immediately with the onset of GRP irradiation, the exposure of PVDF and GRP made of untreated glass cloth results in a drop in the strength only after 50 kGy. The irradiation eliminates the properties acquired by the polymer matrix during the fabrication of GRP, and the properties of the GRP polymer matrix approach those of the initial PVDF with an increase in the radiation dose.

Mechanochemical synthesis and properties of fullerene derivatives

A technique was developed of mechanochemical synthesis of the fullerene C60 water-soluble derivatives. The derivatives obtained were characterized by elemental analysis, IR spectroscopy, and thermogravimetric analysis. The effect the substances obtained on the mechanical properties of the polyvinyl alcohol films was studied. A strengthening effect of fullerene derivatives on the elastic modulus, tensile strength, and tensile deformation of the polyvinyl alcohol films were found to become apparent already at the concentrations of 0.1–0.2 wt %.

Polymeric Dressing Formulations Containing Water-Soluble Fullerene Derivatives

The effect of small additions of water-soluble fullerene C60 derivatives on the strength properties of polyvinyl alcohol films was examined. Solutions of polyvinyl alcohol and fullerenol were tested as polymeric dressing formulations for glass-reinforced plastics based on a thermoplastic polyethylene or polyamide matrix.

Effect of the molecular mobility of epoxy amine crosslinked polymers on their relaxation and physicomechanical characteristics

The results on molecular mobility in epoxy amine crosslinked polymers at segmental (α process) and local (β process) levels are analyzed. The effect of intrachain and interchain rigidities on the above processes is considered, where the intrachain rigidity is measured with the use of flexibilizing agents and the interchain rigidity is dependent on the intermolecular-interaction intensity, which is governed by the introduction of plasticizing agents. Both modes of molecular mobility in the crosslinked polymers show a cooperative character that controls the dissipation energy of the corresponding relaxation process. The correlation between the above processes and the elastic, strength, and relaxation characteristics of the epoxy amine crosslinked polymers is studied. Molecular mobility is shown to exert an inverse effect on the relaxation and dissipative characteristics of the network polymers.

Effect of fullerenes and gamma-irradiation on the adhesive strength of model adhesive joints

The dependence of the adhesive strength of model glass/binder/glass adhesive compositions cured with aliphatic and aromatic hardeners on the γ-radiation dose was studied. It was shown that the strength of the fullerene-modified binder decreases at low absorbed doses (to 20 kGy), whereas the strength of the composition with the aliphatic binder increases again with an increase in the dose in the range 140–240 kGy, although its does not reach that of the unirradiated composite.

Formation of Strength Properties of Model Glue Joints Based on Epoxy-Amine Binders Cured by Polycondensation Mechanism

The kinetics of formation of strength properties were studied for a model glue joint based on epoxyamine binder cured by the polycondensation mechanism at various temperatures. The binder curing kinetics were monitored. In the course of curing, shrinkage defects were studied and the glue joint fracture surface was examined.

Elastification of heat-resistant epoxy polymer matrices

The behavior of fracture toughness parameters in comparison with other physicomechanical parameters of failure was examined with the aim to evaluate the efficiency of modification (elastification) of heat-resistant binders, with four epoxy-amine compounds taken as examples.

Adhesive strength of fullerene-doped epoxyamine compositions

Dependence of adhesive strength of model gluing epoxide compositions glass-binder-glass hardened with aliphatic and aromatic amine hardeners on the fullerene additive content is studied. When aromatic amine is used as a hardener of epoxy-diane resin, addition of fullerenes does not affect the adhesive strength. On the contrary, when aliphatic amine hardener is used, the increase of adhesive strength as compared to nondoped composition was 400%. Use of a mixture of aliphatic and aromatic hardener leads to substantial synergism of their effect on strength properties of the fullerene-doped compositions.

Modification of heat-resistant epoxy matrices with acryl-containing oligomers

With the aim to enhance the crack resistance and impact resilience of heat-resistant epoxy polymeric matrices for high-strength composites, modification of epoxy resins with new poly(ether acrylates) and their adducts with amines was studied.

The effect of gamma-radiation on polymer composites based on thermoplastic matrices

The effect of 60Co γ-radiation on polymer composite materials (PCMs) based on reinforcing glass cloth, polyethylene (PE), polyamide (PA) and polypropylene (PP) matrices has been studied. It has been found that PCMs based on more durable PP and PA matrices have a substantially lower radiation resistance as compared to their PE-matrix analogs. More stable carbon-reinforced plastics based on the PE matrix also have a lower radiation resistance as compared to fiberglass plastics. High-strength PE fiber, PE film, and PE-matrix composites behave in fundamentally different manners under the action of radiation.