Effect of the amount of curing agent,curing temperature,and polarization on physicomechanical characteristics of epoxyamine adhesive compositions based on DER-331 oligomer

The effect of the amount of amine curing agent and temperature of curing on physicomechanical properties of adhesive composition based on DER-331 epoxy oligomer under the action of polarization under a constant electric field has been investigated. It has been shown that the transition of network polymer structures into a polarized state leads to an increase in their strength properties.     

Adhesive compositions based on perchlorovinyl resin with enhanced adhesion to polymeric elastic materials

A possibility of modifying the adhesive compositions based on perchlorovinyl resin with amino-containing compounds is studied. Aniline and N-nitrosodiphenylamine were used as amino-containing adhesion promoters. It is shown that, at an optimal content of an adhesion promoter, ED-20 resin, and plasticizer additives in the gluing composition, the bond strength of vulcanized resins based on different rubbers and linoleum increases by 1.7–3.3 times.     

Study of effect of epoxynovolac oligomer on rheokinetics of curing of epoxyamine composition

The effect of epoxynovolac resin on hardening process in ED-22 epoxide oligomer is studied using the method of rotational viscometry.     

Synthesis of a Val-Pro diaminodiol dipeptide isostere by epoxyamine cyclization

[reaction: see text] The stereoselective synthesis of a novel proline-containing dipeptide isostere is described. Starting from l-valine, three new contiguous stereocenters are generated by asymmetric induction and epoxide chemistry, while the pyrrolidine ring of proline is introduced in the final step via intramolecular ring opening of the amino acid derived epoxyamine. Proline-containing peptidomimetics are potentially attractive as selective inhibitors of proline-specific enzymes, such as PPIases and retroviral proteases, and as analogues of bioactive peptides.     

Novel nanocomposites based on silver nanoparticles and mixed epoxyamine networks

A procedure has been proposed for the direct synthesis (without the use of reductants) of silver nanoparticles in an epoxy polymer matrix with the formation of novel nanocomposites. The average size of the formed nanoparticles has been shown to be about 18 nm. The polymer cross linking leads to the formation of chain aggregates of the nanoparticles. Nanocomposites containing isolated (individual) silver nanoparticles can also be obtained.     

Contact-layer method in adhesive mechanics: Adhesive strength during normal detachment

The contact-layer method is used to solve the problem of stressed-deformed state and strength in the adhesive attachment model, designed for normal detachment tests. The influence of different model and experimental parameters on the normal destructive stress measured in experiments is studied. It is shown that tangent stresses are distributed nonuniformly over the sticking area and that the strength in the model is determined by the competition of normal and maximum tangent stresses.     

Improvement of adhesion strength of compositions based on chlorosulfonated polyethylene to rubbers

In order to increase the adhesion strength to rubbers, chlorosulfonated polyethylene was modified with amino-containing compounds. It is shown that such modification increases the adhesion strength of the compositions to resins by two to five times.     

Preparation of nanocomposites consisting of an epoxyamine polymer matrix with silver nanoparticles

A promising method is presented for the preparation of polymer composites in situ containing stabilized silver nanoparticles without the use of additional reducing systems. The effects of functionality and the structure of the epoxyamine polymer matrices on their capacity to reduce silver ions and stabilize growing silver nanoparticles were evaluated.     

Influence of colloidal structure of polymer mixes on adhesion strength of polyolefin compositions

Mixtures of low-density polyethylene and ethylene-vinyl acetate (EVA) copolymer are studied. It is shown that the adhesion value is defined by the polymer that forms a dispersion medium in the adhesive compositions and the type of fracture depends on the competing influence of the physical and mechanical parameters and the reduced acidity parameter of the polymer, which forms a continuous phase.     

A method for improving the adhesion strength of UV-curable polymer compositions to metal

A method for improving the adhesion strength of UV-curable polymer compositions to metal is suggested that is based on the production of an adhesion layer at a metal surface, which is able to undergo polymerization with the components of the applied composition under the action of UV irradiation.     

Studying the curing of epoxyamine mixtures via dynamic light scattering and differential scanning calorimetry

The curing of epoxy oligomers with different structures and reactivity using an aliphatic amine curing agent was studied and quantitatively characterized by the methods of dynamic light scattering and differential scanning calorimetry. The presence of disperse phase in the initial reagents, as well as in the reacting systems is established. It is shown that the particles of the disperse phase are involved in the process of curing even in the early stages. By changing the width of the devitrification region, the change in the molecular homogeneity of epoxyamine systems during curing is estimated.     

Preparation of highly photosensitizing liposomes with fullerene-doped lipid bilayer using dispersion-controllable molecular exchange reactions

Fullerene-containing liposomes with high photosensitization ability were prepared. Disaggregated fullerenes were efficiently injected into the bilayer of liposomes by a phototriggered molecular exchange reaction. These liposomes showed far higher photoreactivity than liposomes thermally produced by heating and microwave irradiation. This result indicates that control of self-aggregation of fullerene leads to a high quantum yield for the photoreaction because of the suppression of self-quenching of photoexcited fullerenes.     

Effect of poly(arylene ether ketone)s of different chemical constitutions on adhesion properties of epoxyamine binder

The adhesive strength at the bipolymer blend/fiber interface was determined by the pull-out method. Epoxy resin blends with heat-resistant linear thermoplastics, poly(arylene ether ketone)s of different molecular masses and chemical compositions, were used as adhesives, and a steel wire of 150 μm diameter was used as a substrate. It was found that the addition of 5–20 wt % poly(arylene ether ketone) to epoxy resin results in a 10–20% increase in the adhesive strength; a sharp gain in the adhesive strength (by 50–80%) is observed at a modifier content of 30%. The introduction of nanoparticles (Na⁺-montmorillonite) into the epoxy resin-poly(arylene ether ketone) blend increases the strength of adhesive bonding to steel wire. Possible reasons for the observed changes in the adhesive strength are discussed.     

Adhesive properties of ethylene and vinyl acetate copolymer. Deformation strength characteristics: Contribution of plastic deformation work

The deformation-stress curves of ethylene and vinyl acetate copolymer (EVA) are determined by traditional methods with respect to composition at various rates of deformation. The residual deformations after relief are estimated. The deformation work is calculated and the effect of copolymer composition on the value of plastic deformation is evaluated. According to the previously suggested model, the contribution of deformation characteristics of EVA adhesive to the adhesive joint fracture energy is estimated.     

Asymmetric syntheses of (-)-lentiginosine and an original pyrrolizidinic analogue thereof from a versatile epoxyamine intermediate

Ready access to natural (-)-lentiginosine and its pyrrolizidinic analogue from a chiral vinylic epoxyamine in a straightforward five-step sequence is presented. Careful use of the RCM reaction on aminotriols and constitutes the key feature of the synthetic pathway. The alpha-amyloglucosidase inhibitory activities of the target compounds were evaluated and showed that the more easily accessible pyrrolizidinic analogue possesses an inhibitory activity quite similar to that of (-)-lentiginosine.     

Adhesive prepregs

An assortment of prepregs representing adhesive matrices with regulated strength and heat resistances reinforced with glass and carbon fibers of different structures is reported. The processing of adhesive prepregs into items used for the production of honeycomb structures with simple and complex curvatures in one process step is described.     

Adhesive liquid-crystalline polymers

The synthesis and characterization of liquid-crystalline polymers with possible good adhesive properties is reported. These polymers are prepared by alternating copolymerization of maleic anhydride and mesogenic alkenes. The spacer length m is varied (m = 2, 3, 4, 6, 8 and 9) and methoxybiphenyl is used as the mesogenic group. The glass transition temperature decreases and the isotropization temperature increases with spacer length. Depending on the spacer length and temperature, S_B and S_Ad mesophases can be observed. After annealing, spin-coated films of these polymers show very regular layered structures with a layer spacing similar to that in the bulk.     

Adhesive ability of soot-filled epoxides

The concentration dependence of the adhesive strength in joints of soot-filled epoxides with fibers was investigated. It was shown that this dependence is described by the curve with maximum observed at 2 wt % of soot. Modifying the epoxy resin with soots results in an increase in the interface strength by 20–30%.