Effect of blending sequence on the microstructure and properties of PBT/EVA‐g‐MAH/organoclay ternary nanocomposites

Abstract

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.

Micro- and nano-scale deformation behavior of nylon 66-based binary and ternary nanocomposites

“…Furthermore, it was concluded in our previous study that the best micro-structure for improved mechanical properties is to have the fully exfoliated organoclay located within the nylon 66 matrix rather than in the SEBS-g-MA particles [54]. This result is also in agreement with that of PBT/EVA-g-MA/organoclay ternary nanocomposites, where the sequence of (PBT + organoclay) + EVA-g-MA exhibited best mechanical properties [32].…”

“…4.5 times increase in notched impact strength of PP/clay nanocomposite was achieved by 15 wt% of SEBS-g-MA at the expense of stiffness and tensile strength. Li et al [32] also attempted to obtain toughened poly(butylene terephthalate) (PBT) with higher tensile strength and modulus by using maleated poly(ethylene-co-vinylacetate) (EVA-g-MA) elastomer as a toughener and organoclay as a reinforcing agent. The blending sequence influenced the dispersion states of the organoclay.…”

Effect of blending sequence on microstructure of ternary nanocomposites

“…However, almost two decades after the introduction of the concept of polymer silicate nanocomposites, still substantial understanding of the parameters that result in a good balance between elastic stiffness and fracture toughness of these materials is needed. Many approaches have been adopted in the expectation of achieving this goal, such as by addition of an elastomeric phase to the polymer clay nanocomposites [6,7], usage of organoclay as a compatibilizer for immiscible polymer blends [8], and further modification of organically treated clay with epoxy monomer before blending to produce an intercalated nanocomposite [9]. These methods have resulted in improved tensile strength and elastic modulus along with a slight increase in toughness.…”

Nanocomposites formed from polypropylene/EVA blends

“…If the individual platelets of these organoclays or aggregates with a small number of platelets are dispersed in the polymer matrix even at low loading level of these silicates (about 5 wt%), the resulting nanocomposites can exhibit remarkable improvement in certain properties compared to the neat polymer, e.g., high modulus and heat distortion resistance [4][5][6]. More recently, these two approaches for polymer modification have been used together to achieve polymer systems that combine the properties of blends and nanocomposites, for example, high impact strength and modulus [7][8][9][10][11][12]. However, there is much to be learned about the mechanisms by which the clay platelets influence the morphology and mechanical properties of the blends.…”