Effect of POSS on morphology, thermal and mechanical properties of polyamide 6

Polyamide nanocomposites with different octakis(dimethylsiloxy, 3-glycidoxypropyl)octasilsesquioxanes (POSS) contents (0.5, 2, 4 wt. %) were obtained during melt blending. SEM results showed that POSS are uniformly dispersed in polyamide 6 matrix (Fig. 1). FT-IR and DSC analysis indicated that the addition of POSS promotes modifications of the polyamide crystal structure, which consist of the progressive development of alpha crystals and significant increase in the glass transition temperature, crystallization temperature and the crystallization rate of the polyamide 6 (Figs. 2 and 3, Tab. 1). Tensile tests, performed on dried samples, revealed that strength and elongation at break were appreciably modified by the presence of POSS (Fig. 4, Tab. 2). Compared with the neat polyamide 6, the impact strength of PA 6/POSS composites is enhanced (Tab. 2). Dynamic mechanical thermal analysis (DMTA) demonstrated that both the storage modulus (G') and relaxation temperatures (T-alpha, T-beta and T-gamma), especially glass transition temperature (T-alpha) of the PA6/POSS composites significantly increased (Fig. 5, Tab. 3).