Hydrogenated butadiene-nitrile rubber elastomers: research of functional properties

The subject of the study were rubbers based on partially and fully hydrogenated nitrile-butadiene rubbers (HNBR) Therban АТ 5065 VP and Therban АТ 5005 VP, taken individually and in the ratios 80:20, 70:30, 60:40, 50:50 accordingly. The purpose of the work was to study the functional properties of rubbers based on HNBR of various degrees of unsaturation using modern methods of analysis. The degree of dispersion of the filler and the thermodynamic compatibility of polymer components in rubbers based on Therban АТ 5065 VP and Therban АТ 5005 VP mixtures are appreciated. Glass transition and decomposition temperatures, elastic modulus and mechanical loss tangent of HNBR-based and their combined compositions were identified. The microrelief of the surface of rubber samples based on HNBR, taken in different ratios, was investigated.

Thermodynamic compatibility conditions of a new class of hysteretic materials

The thermodynamic compatibility defined by the Drucker postulate applied to a phenomenological hysteretic material, belonging to a recently formulated class, is hereby investigated. Such a constitutive model is defined by means of a set of algebraic functions so that it does not require any iterative procedure to compute the response and its tangent operator. In this sense, the model is particularly feasible for dynamic analysis of structures. Moreover, its peculiar formulation permits the computation of thermodynamic compatibility conditions in closed form. It will be shown that, in general, the fulfillment of the Drucker postulate for arbitrary displacement ranges requires strong limitations of the constitutive parameters. Nevertheless, it is possible to determine a displacement compatibility range for arbitrary sets of parameters so that the Drucker postulate is fulfilled as long as the displacement amplitude does not exceed the computed threshold. Numerical applications are provided to test the computed compatibility conditions.

Toughening Modification of Polylactic Acid by Thermoplastic Silicone Polyurethane Elastomer

The melt blending of polylactic acid (PLA) and thermoplastic silicone polyurethane (TPSiU) elastomer was performed to toughen PLA. The molecular structure, crystallization, thermal properties, compatibility, mechanical properties and rheological properties of the PLA/TPSiU blends of different mass ratios (100/0, 95/5, 90/10, 85/15 and 80/20) were investigated. The results showed that TPSiU was effectively blended into PLA, but no chemical reaction occurred. The addition of TPSiU had no obvious effect on the glass transition temperature and melting temperature of PLA, but slightly reduced the crystallinity of PLA. The morphology and dynamic mechanical analysis results demonstrated the poor thermodynamic compatibility between PLA and TPSiU. Rheological behavior studies showed that PLA/TPSiU melt was typically pseudoplastic fluid. As the content of TPSiU increased, the apparent viscosity of PLA/TPSiU blends showed a trend of rising first and then falling. The addition of TPSiU had a significant effect on the mechanical properties of PLA/TPSiU blends. When the content of TPSiU was 15 wt%, the elongation at break of the PLA/TPSiU blend reached 22.3% (5.0 times that of pure PLA), and the impact strength reached 19.3 kJ/m2 (4.9 times that of pure PLA), suggesting the favorable toughening effect.

To the Calculation of the Compatibility of Oligomers with High Molecular Weight Rubbers

The article presents a modified theoretical calculation of the solubility parameter for oligomers and polymers, taking into account the influence of their molecular structure. The obtained values of the solubility parameter make it possible to predict thermodynamic compatibility for polymers and oligomers