P.K. Ghosh

MWCNT/TiO2 hybrid nano filler toward high-performance epoxy composite

In this work, multi-walled carbon nanotubes (MWCNTs) are decorated by TiO2 nanoparticles and formed a new hybrid structure of filler (MWCNT/TiO2 hybrid filler). The MWCNT/TiO2 hybrid filler is reinforced in epoxy matrix and studied the mechanical and anti-corrosion properties of epoxy. The morphology of newly formed MWCNT/TiO2 hybrid nano filler has been studied using transmission electron microscopy (TEM). Field Emission Scanning Electron Microscope (FESEM) images of tensile fracture surface confirmed the superior dispersion of MWCNT/TiO2 in the epoxy matrix. The resultant MWCNT/TiO2 hybrid-epoxy nanocomposite exhibits superior anti-corrosion and mechanical performance than the nanocomposite produced by loading of only MWCNTs or TiO2 nanoparticles as well as neat epoxy. For example, tensile strength and storage modulus of epoxy increased by 61% and 43% respectively on loading of MWCNT/TiO2 hybrid nano filler. Furthermore, the coating of MWCNT/TiO2 hybrid-epoxy nanocomposite on mild steel reduces the corrosion rate upto 0.87×10-3MPY from 16.81MPY.

Improving thermal and electrical properties of graphene–PMMA nanocomposite

Ultrasonic dual mixing involving ultrasonic vibration with simultaneous stirring by rotating impeller and conventional ultrasonication processes were used for preparation of homogeneously dispersed graphene–PMMA nanocomposites. Glass-transition temperature, degradation temperature, electrical conductivity and flexural strength of the graphene–PMMA nanocomposite processed by ultrasonic dual mixing are found superior to that processed only by ultrasonication. Moreover, it gives better dispersion of graphene with almost no agglomeration in the PMMA matrix than the simple ultrasonication process.

UDM enhanced physical and mechanical properties through the formation of nanocavities in an epoxy matrix

The matrix modification of relatively low viscous epoxy based polymer treated under ultrasonic mixing (UM) and ultrasonic mixing with simultaneous stirring by a rotating impeller, referred to as ultrasonic dual mixing (UDM), and the effect of processing techniques has been investigated in terms of the formation of nanocavities in the epoxy matrix. Nanocavities of size 42±8nm have been formed uniformly in the epoxy matrix by UDM. The effect of a change in matrix morphology on the viscoelastic, tensile and thermal properties of the cured epoxy resin has been studied. The UDM processed cured epoxy matrix showed 18.26% and 88.34% improvement in tensile strength and toughness as compared to unprocessed epoxy. Thermal gravimetric analysis (TGA) of UDM processed epoxy showed significant enhancement in the thermal stability of the epoxy matrix.

Impact of ultrasonic assisted triangular lattice like arranged dispersion of nanoparticles on physical and mechanical properties of epoxy-TiO2 nanocomposites

Emerging ex-situ technique, ultrasonic dual mixing (UDM) offers unique and hitherto unapproachable opportunities to alter the physical and mechanical properties of polymer nanocomposites. In this study, triangular lattice-like arranged dispersion of TiO2 nanoparticles (average size ∼ 48 nm) in the epoxy polymer has been attained via concurrent use of a probe ultra-sonicator and 4 blades pitched impeller which collectively named as UDM technique. The UDM processing of neat epoxy reveals the generation of triangular lattice-like arranged nanocavities with nanoscale inter-cavity spacing. The UDM processing of epoxy-TiO2 nanocomposites reveals two unique features such as partial and complete entrapping of the nanoparticles by the nanocavities leading the arranged dispersion of particles in the epoxy matrix. Pristine TiO2 nanoparticles were dispersed in the epoxy polymer at loading fractions of up to 20% by weight. The results display that the arranged dispersion of nanoparticles is very effective at enhancing the glass transition temperature (Tg) and tensile properties of the epoxy at loading fractions of 10 wt%. We quantify a direct relationship among three important parameters such as nanoparticle content, cluster size, and inter-particle spacing. Our results offer a novel understanding of these parameters on the Tg and tensile properties of the epoxy nanocomposites. The tensile fracture surfaces revealed several toughening mechanisms such as particle pull-out, plastic void growth, crack deflection, crack bridging and plastic deformation. We show that a strong nanoparticle-matrix interface led to the enhanced mechanical properties due to leading toughening mechanisms such as crack deflection, plastic deformation and particle pull-out. We showed that the UDM has an inordinate prospective to alter the dispersion state of nanoparticles in viscous polymer matrices.