Effect of filler type on properties of PBAT/organoclay nanocomposites

Abstract

The goal of this study is to evaluate the effect of different organoclays on the properties of poly(butylene adipate-co-terephthalate) (PBAT)/organoclay systems. PBAT/organoclay nanocomposites containing 2.5, 5.0 and 7.5% of three different commercial organically modified clays (Cloisite(R) C10A, C20A and C30B) were prepared as a masterbatch in a laboratory internal mixer, let down to the appropriate concentration in a co-rotating twin-screw extruder, and test specimens were injection molded. Nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetry (TGA) and dynamic mechanical analysis (DMA) as a function of clay identity and content. XRD results showed a significant increase in the interlayer spacing of the clay, suggesting that intercalated structures were obtained with all systems investigated, as confirmed by TEM. Organoclay incorporation into PBAT resulted in lower melt crystallization temperatures compared with the neat polymer, particularly in PBAT/C30B nanocomposites, slightly improved thermal stability, increased stiffness and no changes in the glass transition temperature. Compounding PBAT with up to 7.5% of C10A, C20A or C30B organoclays is an option to improve the performance of PBAT.