Effect of structural-chemical modification of a polycaprolactam block on the retention of strength during thermo-oxidation

The structure and strength of a block of polycaprolactam (PC) have been investigated in relation to diffusion stabilization and thermo-oxidation. It is shown that structural modification of the surface layers of the PC block with zinc iodide has an important effect on the retention of strength during prolonged thermo-oxidation.Kaunas Polytechnic Institute; Institute of Physicotechnical Problems of Energetics, Academy of Sciences of the Lithuanian SSR, Kaunas. Translated from Mekhanika Polimerov, No. 1, pp. 10–14, January–February, 1970.     

Investigation of structural features and strength of diffusion-stabilized polymers

Changes in the structure and properties of polyamides accompanied by diffusion stabilization are discussed.     

Reaction of aminoquinolines with methyl acrylate and transformations of some of the products obtained

3H,4H-Quino[1,2-a]-2-pyrimidone, 1-(2-carboxyethyl)aminoquinolinium betaines, and methyl esters of N-quinolinyl--alanines were isolated from the reactions of aminoquinolines with methyl acrylate. Hydrolysis of the latter yielded the corresponding amino acids, two of which were converted to 1-(3- and 6-quinolinyl)dihydrouracils, and the latter was reduced to 1-(6-quinolinyl)-2-oxohexahydropyrimidine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 482–486, April, 1971.     

Some characteristics of the failure of heat-sealed polyethylene film

It is shown that weld failure most often occurs in the inner weld zone. The mode of failure and deformation of the weld in uniaxial tension depends on the welding conditions. For severe welding conditions the _t-T curve has a certain maximum.Institute of Physicotechnical Problems of Power Engineering, Academy of Sciences of the Lithuanian SSR, Kaunas, Kaunas Polytechnic Institute. Translated from Mekhanika Polimerov, No. 3, pp. 537–538, May–June, 1971.     

Ablation resistance of certain epoxy compounds

The rate of ablation in oxidative and inert media at flow velocities up to 200 m/sec has been investigated for certain epoxy compounds containing powdered copper and zinc dust. The causes of ablative destruction and the factors tending to improve the ablation resistance are examined. The contributions of mechanical erosion and thermal shock are evaluated.Mekhanika Polimerov, Vol. 4, No. 1, pp. 72–77, 1968     

Fatigue and fracture of stabilized polycaprolactam

We have investigated the effect of certain antioxidants and structure-forming agents on the mechanism and work of fatigue fracture of polycaprolactam under cyclic loading. We have analyzed the super-molecular structures and fracture surfaces of the most typical stabilized specimens and offer an explanation of the fatigue hardening mechanism in stabilized polycaprolactam.Mekhanika Polimerov, Vol. 3, No. 4, pp. 713–718, 1967     

Structural changes and defect development in epoxy adhesive compounds during thermal aging

The structural characteristics of epoxy adhesive compounds and the development of surface defects during thermal aging have been investigated. Profilograms of the fracture surfaces of bonded joints have been obtained and certain causes of the increased dispersion of the bond strength characteristics explored.Mekhanika Polimerov, Vol. 4, No. 2, pp. 293–295, 1968