Poly(lactic acid) (PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blends were compatibilized using epoxidized polyhedral oligomeric silsesquioxanes (Epoxy-POSS). Three different Epoxy-POSS types were utilized having mono-, tri-, and multi-epoxides per POSS cage. In order to understand the localization of Epoxy-POSS types, wetting coefficients were calculated from surface energy measurements. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was observed that Epoxy-POSS types mostly located at the interface of PLA/PBAT phases. The compatibilization of PLA and PBAT was shown through the decrease in dispersed particles size and the shifts in glass transition temperatures of phases. Mechanical properties of PLA/PBAT improved in the presence of Epoxy-POSS types. The Izod impact strength and elongation in tensile test values were maximized when 0.5% monoepoxy-POSS was used as compatibilizer. The reactions between Epoxy-POSS and polymers were monitored by Fourier transform infrared (FTIR) analysis and rheology.PBAT. 7 PBAT is an aliphatic-aromatic copolymer, which resembles to LDPE in term of its features. It has a great toughness, flexibility, low glass transition temperature, and it is fully biodegradable. PBAT has been considered as a good nominee for the toughening the PLA owing to its high flexibility. 8 However, PLA/PBAT blends show multiphase behavior due to incompatible characters of each component, which results in poor mechanical properties. PLA/PBAT blends can be compatibilized in order to strengthen the interfacial adhesion and to reduce the interfacial tension between phases. 9 Moreover, compatibilization can also improve the morphological stability of the blend.Al-Itry and coworkers used a commercial epoxidized styreneacrylic copolymer as a compatibilizer in PLA/PBAT blends. They found that the compatibilizer enhanced the tensile toughness of PLA/PBAT blends. It was seen from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) pictures that the interfacial adhesion was improved in the presence of compatibilizer. 8 Kumar et al. focused on glycidyl methacrylate (GMA) compatibilizer on the thermal, mechanical, thermomechanical, and morphological properties of PLA/PBAT blends. It was reported that impact strength of PLA/PBAT blends increased in the presence of GMA. The glass transition temperatures of PLA and PBAT phases shifted to each other that proved the enhanced compatibilization. Moreover, the morphological results figured-out that the interfacial adhesion was successfully achieved Additional Supporting Information may be found in the online version of this article.

The aim of this study is to investigate the effects of the reactive and nonreactive polyhedral oligomeric silsesquioxane (POSSs) types and their composition on the mechanical, thermal, and morphological properties of poly(ethylene glycol) plasticized poly(lactic acid) (PLA) composites prepared with melt compounding. The results showed that the incorporation of POSS decreased the melt viscosity of the compounds regardless of POSS type. The lowest viscosity was obtained with epoxy‐POSS, which is the only one that is liquid at processing temperature in comparison to the others. It was revealed from the mechanical tests that the toughness‐related properties such as impact strength and elongation at break improved by the addition of POSS without remarkable deterioration in stiffness. The chemical structure of the POSS influenced the level of dispersion and hence the mechanical performance of the composites. Octaisobutyl‐POSS, being the nonreactive and nonpolar one, had the best dispersion among the other reactive and polar POSS types. The glass transition temperature of the matrix decreased in the presence of POSS types. In addition, the POSS particles also had an impact on the crystallization of PLA. The thermal stability of the composites improved in the presence of POSS particles with respect to the POSS content and the POSS type. POLYM. ENG. SCI., 54:264–275, 2014. © 2013 Society of Plastics Engineers

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In this study, it was aimed to investigate the mechanical, thermal, and morphological properties of PA6 hybrid composites containing talc and wollastonite. Talc and wollastonite filled single and hybrid composites were prepared with melt compounding in a twin screw extruder. The filler content was 40% by weight and the wollastonite/talc ratio was 40/0, 30/10, 20/20, 10/30, and 40/0. The melt flow rate measurements showed that incorporation of fillers into the polyamide 6 (PA6) resulted in an increment in melt viscosity of composites. The presence of a homogeneous dispersion of fillers in the matrix was obtained from morphological analysis. It was revealed from the mechanical tests that in most cases, mechanical properties of 20/ 20 hybrid composites were significantly higher than that of the single and the other hybrid composites. Heat deflection temperature of the composite was markedly improved by the addition of fillers. Differential scanning calorimeter analysis showed that talc and wollastonite acted as a nucleating agent for PA6. POLYM. COMPOS., 36:739-746, 2015.

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