Зміна теплофізичних властивостей поліамідів під впливом полівінілпіролідону

Abstract

The data of temperature-modulated differential scanning calorimetry, thermomechanical and microscopic analyses allowed establishing the effects of poly-N-vinylpyrrolidone (PVP) on the supramilecular structure in the mixtures of PA-6–PVP and PA-66/6–PVP, crystallite sizes, degree of material crystallinity and temperature of physical transitions. The thermodynamic compatibility between the components of polyamide–PVP mixtures in the viscousfluid state is determined. The compatibility between PA-6 and PVP is manifested as one endo-peak observed in the curves of differential scanning calorimetry. The endi-effect is somewhat blurred for the case of PA-66/6. This is explained by the presence of links with various structures in PA-66/6. An increase in PVP content in the mixtures also leads to the growth of the maximal temperatures of peaks in the processes of melting and crystallization and the expansion of their temperature and time ranges. Thermomechanical study showed that the melting temperature increases with an increase in the content of PVP in the case of PA-6–PVP mixtures, whereas it decreases in the case of PA-66/6–PVP mixtures. A decrease of deformation in the area of highly elastic state is observed. Microscopic study of the structure of the materials based on modified polyamides revealed the growth of the size of supràmîleculàr formations and significant changes in the interphase layers. However, the size of crystal formations in the mixtures of PA-66/6–PVP is slightly smaller than in PA-6.