Supratim Suin

Highly exfoliated eco-friendly thermoplastic starch (TPS)/poly (lactic acid)(PLA)/clay nanocomposites using unmodified nanoclay.

Highly exfoliated, biodegradable thermoplastic starch (TPS)/polylactic acid (PLA)/sodium montmorillonite (NaMMT) nanocomposites were prepared by an eco-friendly approach, involving in-situ gelatinization of potato starch in presence of dispersed nanoclay followed by melt mixing with PLA. The morphological analysis revealed that the NaMMT was selectively dispersed into the TPS in a highly delaminated manner. An increase in mechanical as well as thermomechanical properties was evident in the presence of PLA and more influenced in the presence of clay. The water absorption was significantly decreased in the presence of PLA (∼8%) itself and both PLA and clay (∼8-12%) in the nanocomposites. The improved mechanical properties along with its biodegradability might lead to a new green material in the area of packaging.

A strategy to achieve high electromagnetic interference shielding and ultra low percolation in multiwall carbon nanotube–polycarbonate composites through selective localization of carbon nanotubes

Here, we report a simple method that involves solution blending of polycarbonate (PC) in the presence of multiwall carbon nanotubes (MWCNTs) and commercial PC beads for the preparation of electrically conducting MWCNT–PC composites with high electromagnetic interference shielding effectiveness (EMI SE) and electrical conductivity at very low (∼0.021 wt%) percolation threshold (pc). Thus, electrical conductivity of ∼4.57 × 10−3 S cm−1 was achieved in the MWCNT–PC composites at an extremely low MWCNT loading (0.10 wt%) in the presence of 70 wt% PC beads in the composites. Finally, optimizing the ratio of PC beads and MWCNT loading in the composites, a very high EMI SE value (∼23.1 dB) was achieved at low loading (2 wt%) of MWCNT with 70 wt% PC beads. The effective concentration of MWCNT increases in the solution blended PC region with increasing the amount of PC beads. Thus, a strong interconnected conductive network structure of CNT–CNT is developed throughout the matrix and the presence of strong π–π interaction among the electron-rich phenyl rings of PC and MWCNT in the composites plays a crucial role in increasing the EMI shielding value and electrical conductivity of the MWCNT–PC composites.

Compatibilization Mechanism of Nanoclay in Immiscible PS/PMMA Blend Using Unmodified Nanoclay

Organically modified nanoclays have been reported to play the role of a compatibilizer for immiscible polymer blends. However, the mechanism of compatibilization by nanoclay has been reported differently. In this work, we investigated the exact mechanism of compatibilization of nanoclay in immiscible polystyrene (PS)/poly(methyl methacrylate) (PMMA) blend in the presence of sodium-montmorillonite (Na-MMT) through selective dispersion of clay in the matrix phase. Through a detailed investigation of the morphology of PS/PMMA/Na-MMT blend nanocomposites, the plausible mechanism behind the compatibilization effect of clay in immiscible blends has been proposed.

An approach to reduce the percolation threshold of MWCNT in ABS/MWCNT nanocomposites through selective distribution of CNT in ABS matrix

In this article, we demonstrate a facile route to prepare ABS/MWCNT nanocomposites with high electrical conductivity at a significantly low percolation threshold of the CNT. The strategy involves in situ co-polymerization of styrene and acrylonitrile monomers in the presence of multi-wall carbon nanotubes (MWCNT) and commercially available acrylonitrile butadiene styrene (ABS) beads. A dramatic improvement in the electrical conductivity in the nanocomposites was evident with increasing content of ABS beads at a constant CNT loading, which might be explained in terms of the formation of a continuous network structure of CNTs throughout the in situ polymerized ABS matrix. Such selective dispersion of MWCNTs results in an electrical conductivity (3.01 × 10−7 S cm−1) in the nanocomposites at 30 vol% loading of ABS beads and 0.24 vol% loading of MWCNTs. An increase in electrical conductivity to 4.50 × 10−5 S cm−1 was evident when the ABS bead content was increased to 60 vol% at the same loading of MWCNTs. The morphological analysis of the nanocomposites indicates selective distribution of the MWCNTs in the in situ co-polymerized ABS phase of the nanocomposites leaving the externally added ABS beads free from CNT dispersion. This leads to an increase in effective concentration of the CNTs in the in situ co-polymerized ABS phase of the nanocomposites, which in turn creates a path of MWCNTs throughout the matrix, resulting in a decrease in the percolation threshold of the nanocomposites to a lower value (0.2 vol% MWCNT).

Transparent and Thermally Conductive Polycarbonate (PC)/Alumina (Al2O3) Nanocomposites: Preparation and Characterizations

We report the preparation and characterization of thermally conductive and transparent polycarbonate (PC)/alumina (Al2O3) composites. First, nano Al2O3 powder was synthesized by flash pyrolysis process and calculated amount of Al2O3 was dispersed into the methylmethacrylate (MMA) followed by bulk polymerization. PC/poly-(methylmethacrylate) (PMMA)-Al2O3 nanocomposites with various amounts of Al2O3 was prepared by mixing bulk polymerized PMMA-Al2O3 composites with PC through melt-mixing. Incorporation of Al2O3 in the bulk polymerized PMMA resulted in good dispersion of the Al2O3 particles in the PC matrix. The effect of particle size of Al2O3 on thermal conductivity, mechanical and optical properties of the composites was investigated.