Carbon nanotubes interaction with amorphous and semi‐crystalline domains of polypropylene in melt‐mixed composites: Influence of multiwall carbon nanotubes agglomerate and their modifications

Abstract

Polypropylene (PP) and multi‐walled carbon nanotubes (MWCNTs) composites were prepared by melt‐mixing with two types of MWCNTs of varying agglomerate size. Agglomerate dominated dispersion was observed in the PP matrix, wherein N‐MWCNTs exhibit a finer dispersion as compared to D‐MWCNTs. Further, MWCNTs were encapsulated by Li‐salt of 6‐amino caproic acid in various proportions along with PP‐g‐maleic anhydride in order to achieve finer MWCNTs dispersion. Thermogravimetric analysis exhibited an increase in onset of degradation temperature and higher residual weight (%) at 500 °C of PP with increased MWCNTs concentration, which suggests the formation of a thicker “interphase.” Glass transition temperature of the PP phase was increased monotonically as a function of unmodified MWCNTs concentration, which suggests a strong interfacial interaction between PP and MWCNTs. An extensive analysis was carried out with modified MWCNTs based PP composites. Moreover, MWCNTs act as a strong hetero‐nucleating agent manifesting in smaller spherulite size of PP, wherein bulk crystallization temperature is increased to ~130 °C of the PP phase at 5 wt% MWCNTs content. The influence of unmodified and modified MWCNTs on the interaction between the PP chains and MWCNTs in the amorphous phase as well as in the crystalline domains are analyzed in PP/MWCNTs composites.

2D Nanomaterials Incorporated Poly(vinylidene fluoride) Nanocomposites: Morphology, Crystalline Structure, and Dielectric, Ferroelectric, and Piezoelectric Properties

“…Moreover, it is also observed (Table S1) that the parameter T m – T c decreases with the increase in h-BN concentration. The decrease in T m – T c suggests an increase in the rate of crystallization of PVDF in the presence of h-BN . It is important to note that the addition of “ultrasonicated” and “centrifuged” 0.16 wt % of h-BN in PVDF leads to a T m of ∼172.5 °C and X c = ∼53.2% (Table S1), suggesting the formation of the β-crystalline form of PVDF with a higher extent of crystallinity as compared to pure PVDF.…”

“…The decrease in T m − T c suggests an increase in the rate of crystallization of PVDF in the presence of h-BN. 47 It is important to note that the addition of "ultrasonicated" and "centrifuged" 0.16 wt % of h-BN in PVDF leads to a T m of ∼172.5 °C and X c = ∼53.2% (Table S1), suggesting the formation of the β-crystalline form of PVDF with a higher extent of crystallinity as compared to pure PVDF. Further, the crystallization studies show an increased T c of ∼139.9 °C at 0.16 wt % h-BN in the PVDF/h-BN nanocomposite with a significant decrease of T m − T c .…”