Agnieszka Szadkowska

Poly(phenylene oxide) and Renewable Polyamide 11 Blends Compatibilized by Ethylene-n-Octene Copolymer

Poly(phenylene oxide)/renewable polyamide 11 (PPO/PA11 20/80) blends toughened with glycidyl methacrylate grafted ethylene-n-octene copolymer (GEOC) were prepared in a co-rotating twin-screw extruder. The reaction between GEOC and PPO/PA11 blend was analyzed by gel content tests. The morphology of PPO/PA11/GEOC blends was observed by scanning electron microscope. The SEM results showed that PPO formed the continuous phase, though it is a minority component of blends. With increasing GEOC content from 5 to 15 wt% the morphology of the blends transformed from droplet-matrix to co-continuous structure, in which both PA11 and PPO phases are continuous. The blend with co-continuous morphology had better mechanical properties than those with droplet-matrix morphology. The impact strength of the PPO/PA11/GEOC blends was much higher compared to the one without GEOC as well as PA11 due to the compatibilizing effect, which was also proved by DSC analysis, rheological behavior (MFR, DMTA) and tensile properties.

Characteristics of Biodegradable Polylactide/Thermoplastic Starch/Nanosilica Composites: Effects of Plasticizer and Nanosilica Functionality

The effect of plasticizer (polydimethylsiloxanol) and neat (SiO2) or modified (having amine functional groups) silica (A-SiO2) on morphology, thermal, mechanical, and rheological properties of PLA/TPS blends compatibilized by maleated PLA (MPLA) was investigated. Toughened PLA/MPLA/TPS (60/10/30) blend containing 3 wt.% of plasticizer and various contents (1, 3, or 5 wt.%) of silica were prepared in a corotating twin-screw extruder. From SEM, it is clear that plasticized PLA/MPLA/TPS blend continuous porous structure is highly related to the silica content and its functionality. The results indicate that polydimethylsiloxanol enhances ductility and the initial thermal stability of the plasticized blend. DSC and DMTA analyses show that nucleation ability and reinforcing effect of A-SiO2 on plasticized blend crystallization are much better than those of SiO2. Silica practically had no effect on the thermo-oxidative degradation. However, the composites with A-SiO2 had better thermal stability than those with SiO2. Moreover, silica significantly improved the elongation at break.