Influence of the organoclay localization on structure features and properties of polyamide 6/functionalized polyolefins blends

The effect of 1.5 wt. % Cloisite 30B organoclay (Cl30B) containing the hydroxyethyl fragments in the surfactant structure on polyamide 6 (PA 6) / functionalized polyolefin (fPO) – a mixture of linear low-density polyethylene and ethylene copolymer with higher olefin – on the structure, mechanical and rheological properties of the materials was studied. The fPO concentration in the blends was varied from 15 to 50 wt. %. The fPO production and the blend compounding were carried out in melt using a twin-screw mixing reactor. The organoclay in the composition of the blends was introduced in two ways: simultaneously with all polymer components (one-step process) and with its preliminary localization in the PA 6 phase (two-step process). It was established that the complex of static and dynamic mechanical and also rheological characteristics of materials and the crystallisability of the components in the blends depend on the way of the Cl30B distribution in the PA6 and fPO phases, as well as on the phase structure of the blends. The organoclay localization mainly in the polyamide phase leads to a 1.3–3.0 time increase of the impact strength of the blends in which fPO forms a dispersed phase and increases their deformation capacity under tension up to 1.2 times regardless of the phase structure. The organoclay blends localized in the PA 6 phase have increased the values of melt flowability and mechanical loss angle tangent at the PA 6 a-relaxation transition and dynamic shear modulus in the temperature range from –100 to 150 °С compared to the materials produced by one-stage technology, which is explained by the blocking of organoclay amide and other polar groups in the structure of PA6 macromolecules in the polyamide phase and by a decrease as a result of this intensity of interfacial interactions with fPO.

Multiple electrical phase transitions in nanocrystalline aluminium-substituted cobalt ferrite

Electrical properties of a series of nanocrystalline aluminium-substituted cobalt ferrite CoAl[Formula: see text]Fe[Formula: see text]O4 (CAFO) with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5 have been explored. The electrical parameters have been measured by employing impedance and techniques. The impedance has measured as a function of frequency and temperature for all the samples. The impedance increases with the increase in Al concentration in CAFO. Cobalt ferrite is yet to be verified as a ferroelectric material. However, the electrical properties reported here are similar to conventional ferroelectric materials. Multiple (two) electrical phase transitions have been observed, the two transition temperatures are identified as T[Formula: see text] and T[Formula: see text] i.e., one is dipole relaxation transition (T[Formula: see text]) and other one is electrical phase transition temperature. Both AC and DC measurements indicate the transition temperatures.

Effect of secondary relaxation transitions on photo-induced anisotropy in glassy azobenzene-functionalized polymers

The β-relaxation transition in side-chain azobenzene-functionalized amorphous polymers can be directly found from the temperature behavior of infrared dichroism.