Tuhin Chatterjee

Exploring the influence of electron beam irradiation on the morphology, physico-mechanical, thermal behaviour and performance properties of EVA and TPU blends

The effects of electron beam radiation (EBR) on the blends of ethylene vinyl acetate/thermoplastic polyurethane (EVA/TPU) at two different blend ratios prepared via melt blending technique were investigated. All the samples were irradiated by using a 2.5 MeV electron beam accelerating energy over a dose range from 25 to 200 kGy. The blends exhibit drastic improvement in the mechanical properties with increasing radiation dose upto an optimum dosage, beyond which the properties began to deteriorate. Modification of the blends via EBR enhances the elastic recovery of the blends resulting significant improvement in tension set behaviour. DSC study shows that electron beam irradiation causes a marginal change in melting temperature (Tm), glass transition temperature (Tg) and crystallization peak temperature (Tc) of EVA/TPU blends. Dynamic mechanical analysis (DMA) was conducted to investigate the change of loss tangent and storage modulus with varying radiation dose. Thermogravimetric analysis (TGA) suggests that irradiation induced crosslinks also help to improve the thermal stability of the blends to some extent. Scanning electron microscopy (SEM) study was performed to explore the changes in morphology before and after irradiation. All the irradiated blends have higher electrical resistivity than the blends without irradiation and the volume resistivity increases upto 150 kGy. The samples were found to exhibit remarkable improvement in oil resistance property after irradiation which is more prominent in EVA/TPU 70/30 blends.

Polymer-Carbon Composites as Anti-corrosive Materials

The objective of this chapter is to focus on the recent developments of polymer-carbon composites in terms of utilizing various forms of carbon, i.e., graphene or graphene-like sheets, carbon nanotube, along with polymer binder for high-performance anti-corrosive paints. The attributes to final properties of dried film coating can be resolved into two major parts, i.e., attributes due to binder and additives. The role of binder and additives has been discussed separately in the subsequent sections. A general idea has also been discussed as a premise to give the right context before the objective of this chapter is discussed, i.e., Polymer-carbon composites as anti-corrosive material.

Studies on Interfacial Characteristics of Highly Dispersible Silica Reinforced Epoxidized Natural Rubber Compounds

ABSTRACT The present work examines the effect of two different specific surface areas of highly dispersible silica (HDS)-reinforced epoxidized natural rubber (ENR) composites. The influences of different blend ratio between ENRs consisting 25 and 50 mol% of epoxidation-based (ENR-25/ENR-50) composites was studied in detail. The primary objective is to investigate the interfacial area of HDS surface involved in filler-to-rubber interaction mechanisms for the better reinforcement. Notable improvement in overall properties of these green composites are corroborated with various meticulous characterization including cure characteristics, specific bound rubber content, physicomechanical, dynamic mechanical properties, etc. Increasing the specific surface area of HDS and their subsequent interface with ENR matrix invokes its superior dispersion. Small angle X-ray scattering (SAXS) has been used to analyze the particles network and clusters establishment in green composites. The present SAXS method provides a unique insight into the cluster formation according to the Beaucage model. However, SAXS results demonstrate that particles networks can be effectively suppressed by increasing specific surface area of HDS. GRAPHICAL ABSTRACT

Thermo-Sensitive Shape Memory Polymer Nanocomposite Based on Polyhedral Oligomeric Silsesquioxane (POSS) Filled Polyolefins

ABSTRACT Shape memory polymer nanocomposite of EOC-EPDM blend has been prepared by the incertion of two different types of POSS nanoclay namely octaisobutyl POSS and trisilanolIsobutyl POSS. Compared to TSIB POSS, OIB POSS shows significant impact upon the shape memory behaviour of the blend. With increasing amount of POSS nanoclay, reduction in percentage shape fixity is lower for the nanocomposite containing OIB POSS rather than the TSIB POSS containing nanocomposite. On the other side, presence of closed cage like structure also results higher shape recovery ratio and lower shape recovery induction time for OIB POSS containing nanocomposite. GRAPHICAL ABSTRACT

Exploring the Influence of Methylene Diphenyl Diisocyanate as a Modifier for Ethylene Vinyl Acetate/Thermoplastic Polyurethane Blends

ABSTRACT Ethylene vinyl acetate (EVA)/thermoplastic polyurethane (TPU) blend at various blend ratios has been modified via reactive processing with 4,4′-methylene diphenyl diisocyanate (MDI). Modification of the blends with even small amount of MDI shows significant improvement in physico-mechanical properties for EVA/TPU 50/50 and 30/70 blends, and it is also supported by the superior melt rheological behavior and dramatic improvement in oil resistance property. After the treatment of electron beam (dose range: 50–150 kGy), radiation crosslinked EVA/TPU (30:70) blend reveals further improvement in various properties. This particular material can find potential application as cable sheathing component. GRAPHICAL ABSTRACT

Polymer Nanocomposites for Shape-Memory Applications

The dynamic response of the materials to the external stimuli makes it intelligent or smart, and the smart materials have promising applications in many areas. Shape-memory polymers (SMPs), a class of smart materials, exhibit a rapid change from a normal rigid state to a stretchy elastic state and then come back to the original state in the presence of external stimulus. SMPs have several advantages which include multiple sensitivity of the materials, highly flexibility in programming, various structural designs of materials, fine-tuning of the property by proper blending, and formation of composite. Still SMPs have many disadvantages, including poor mechanical properties, low shape fixity and poor shape recovery stress, and shape recovery ratio. Therefore, the development of shape-memory nanocomposites is a matter of concern to improve the shape-memory behavior, stiffness, etc. Various SMP nanocomposites have been developed by incorporation of carbon nanofiber (CNF), carbon nanotube (CNT), nanoclay, nanosilicon carbide, carbon black, and inorganic fillers into the polymer matrix. Incorporation of nanoparticles leads to the development of electrical-sensitive, light-sensitive, magnetic-sensitive, and water-/solvent-sensitive SMP nanocomposites with special features.