Structure-properties correlations in compatibilized polyamide/thermoplastic elastomer/nanoclay mixtures: interrelationship among non-isothermal crystallization kinetics, morphology and viscoelastic responses

In this study, the influences of styrene-butadiene-styrene block copolymer (SBS), a thermoplastic elastomer, nanoclay (NC) and maleic anhydride grafted styrene-ethylene/butylene-styrene (m-SEBS), a compatibilizer, on the non-isothermal crystallization kinetics of polyamide 12 (PA12) have been evaluated using different theoretical models including Avrami, Jeziorny, Ozawa and Mo as well as Kissinger, Takhor and Augis and Bennett equations. Using microscopic observations, X-ray diffraction patterns and rheological responses, the interrelations among the crystallization kinetics variables, morphology and molecular dynamics of compatibilized PA12/SBS rubber/NC mixtures have been thoroughly investigated. A study on different kinetics variables such as crystallization half-time, Avrami index and F(T) demonstrates that the PA crystallization rate has an upward trend against the compatibilizer level within the studied compatibilizer content, while the rate shows a maximum value against NC loading and SBS content. The calculation of the rubber particles diameter, the distance between the rubber particles, PA/SBS interfacial area and normalized chain relaxation time clarifies that more heterogeneous nucleation sites are provided for PA chains by NC platelets and SBS particle surfaces at higher contents (higher amounts in the ranges of 15-21 mass% for SBS and 3-7 mass% for NC), though the molecular movements are restricted more as well, which reduces the growth rate of PA crystals.

Automated summary

This study evaluates the influences of SBS, NC, and m-SEBS on the non-isothermal crystallization kinetics of PA12 using various theoretical models. The interrelations among the crystallization kinetics variables, morphology, and molecular dynamics of PA12/SBS rubber/NC mixtures were thoroughly investigated. The results show that the PA crystallization rate increases with the compatibilizer level, reaches a maximum value with NC loading and SBS content, and is affected by the heterogeneity of nucleation sites provided by NC platelets and SBS particle surfaces.