Morphology and Properties of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide 11 Hybrid Nanocomposites: Effect of Silica Surface Modification

Poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 11 (PPO/PA11 80/20) blend filled with neat (SiO2) or modified silica having amine functional groups (A-SiO2) was melt mixing in a twin-screw extruder. The silica was prepared by the sol–gel process. SEM shows that, with increasing A-SiO2 content from 1 to 5 wt.%, the morphology of PPO/PA11blend changed from droplet matrix to co-continuous with phase inversion. The phase inversion was also observed for 5 wt.% of neat silica, but the droplet-matrix structure was retained. The overall rheological and mechanical properties improvement of the A-SiO2-filled composites in comparison with the unfilled blend and neat silica counterpart was drastic, especially in terms of viscosity and stiffness. A-SiO2 improved PPO and PA11 miscibility and reduced the crystallinity of PA11, without affecting the Tc, owing to the compatibilization effect. On the other hand, neat silica slightly increased the crystallinity of PA11 and decreased the crystallization temperature of PA11 and the glass transition temperature of PPO as a result of its plasticization

Morphology and Properties of Poly(2,6-dimethyl-1,4-phenylene oxide)/Polyamide 11 Hybrid Nanocomposites: Effect of Silica Surface Modification

Poly(2,6-dimethyl-1,4-phenylene oxide)/polyamide 11 (PPO/PA11 80/20) blend filled with neat (SiO2) or modified silica having amine functional groups (A-SiO2) was melt mixing in a twin-screw extruder. The silica was prepared by the sol–gel process. SEM shows that, with increasing A-SiO2 content from 1 to 5 wt.%, the morphology of PPO/PA11blend changed from droplet matrix to co-continuous with phase inversion. The phase inversion was also observed for 5 wt.% of neat silica, but the droplet-matrix structure was retained. The overall rheological and mechanical properties improvement of the A-SiO2-filled composites in comparison with the unfilled blend and neat silica counterpart was drastic, especially in terms of viscosity and stiffness. A-SiO2 improved PPO and PA11 miscibility and reduced the crystallinity of PA11, without affecting the Tc, owing to the compatibilization effect. On the other hand, neat silica slightly increased the crystallinity of PA11 and decreased the crystallization temperature of PA11 and the glass transition temperature of PPO as a result of its plasticization

Morphology and Selected Properties of Modified Potato Thermoplastic Starch

Potato thermoplastic starch (TPS) containing 1 wt.% of pure halloysite (HNT), glycerol-modified halloysite (G-HNT) or polyester plasticizer-modified halloysite (PP-HNT) was prepared by melt-extrusion. Halloysites were characterized by FTIR, SEM, TGA, and DSC. Interactions between TPS and halloysites were studied by FTIR, SEM, and DMTA. The Vicat softening temperature, tensile, and flexural properties were also determined. FTIR proved the interactions between halloysite and the organic compound as well as between starch, plasticizers and halloysites. Pure HNT had the best thermal stability, but PP-HNT showed better thermal stability than G-HNT. The addition of HNT and G-HNT improved the TPS’s thermal stability, as evidenced by significantly higher T5%. Modified TPS showed higher a Vicat softening point, suggesting better hot water resistance. Halloysite improved TPS stiffness due to higher storage modulus. However, TPS/PP-HNT had the lowest stiffness, and TPS/HNT the highest. Halloysite increased Tα and lowered Tβ due to its simultaneous reinforcing and plasticizing effect. TPS/HNT showed an additional β-relaxation peak, suggesting the formation of a new crystalline phase. The mechanical properties of TPS were also improved in the presence of both pure and modified halloysites