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Ternary nanocomposites based on poly(butylene terephthalate) (PBT), maleic anhydride grafted poly(ethylene‐co‐vinyl acetate) (EVA‐g‐MAH), and organically modified montmorllonite (organoclays) were prepared through four different blending sequences in a Haake rheocord mixer: (1) To blend PBT, EVA‐g‐MAH and organoclays in one step; (2) First to prepare EVA‐g‐MAH/organoclay nanocomposite, then mix it with PBT to get the final nanocomposite; (3) To mix PBT with organoclays first, then the PBT/organoclay nanocomposite with EVA‐g‐MAH. (4) To mix organoclays with the PBT/EVA‐g‐MAH blend. The microstructure of the PBT/EVA‐g‐MAH/organoclay ternary hybrids was characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). It was found that the blending sequence significantly influences the microstructure of PBT/EVA‐g‐MAH/organoclay ternary hybrids and the dispersion behavior of the organoclays in the polymer matrix. Tensile and impact properties of the hybrids were also studied. The results showed that the mixing sequence (2) gives the best tensile and impact strength due to its fine “sea‐island” morphology of PBT/EVA‐g‐MAH blend and good dispersion of the organoclays in the continuous PBT matrix.

ABSTRACT:In the present study, blends of starch with different thermoplastics were prepared by a melt blending technique. The tensile properties and morphology of the blends were measured. It was found that with increasing starch content in starch/ionomer blends, the tensile strength and modulus increase. But for starch/low-density polyethylene (LDPE) and starch/aliphatic polyester (APES) blends, tensile strength and modulus decrease with increasing the starch loading. Elongation at break values of all the blend systems decrease with increasing starch loading. The scanning electron micrographs (SEM) support the findings of tensile properties. Better homogeneity is observed in starch/ ionomer systems compared with that in starch/APES and starch/LDPE systems. Up to 50% starch content, the starch/ ionomer blends appear as a single phase. The extent of phase interactions of starch/APES system lies in between the starch/LDPE and starch/ionomer systems. From the biodegradability studies of the blends it was found that, although the pure LDPE and ionomer are not biodegradable, the starch/LDPE and starch/ionomer blends are biodegradable with an appreciable rate. The rate of biodegradation of the starch/APES is very high as both the components are biodegradable.

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