R. R. N. Sailaja

Effect of Nanoclay Content and pH of the Medium on the Swelling Characteristics of Grafted and Cross-Linked Mixed Chitosan Derivatives

A mixture of chitosan and carboxy methyl chitosan along with silane functionalized nanoclay has been grafted with acrylic acid followed by cross-linking. The nanocomposites were then examined for swelling characteristics in acidic, alkaline and neutral medium. In all the three mediums, an optimal clay content with maximum swelling was observed. The thermal characterization of the nanocomposites was also carried out.

Cross-linked Chitosan/Thermoplastic Starch Reinforced with Multiwalled Carbon Nanotubes Using Maleate Esters as Coupling Agent: Mechanical, Tribological and Thermal Characteristics

Bio-nanocomposites have been developed using cross-linked chitosan and cross-linked thermoplastic starch along with acid functionalized multiwalled carbon nanotubes (f-MWCNT). The nanocomposites developed were characterized for mechanical, wear, and thermal properties. The results revealed that the nanocomposites exhibited enhanced mechanical properties. The composites containing 3% f-MWCNT showed maximum compression strength. Tribological studies revealed that, with the addition of small amount of f-MWCNTs the slide wear loss reduced up to 25%. SEM analysis of the nanocomposites showed predominantly brittle fractured surface. Thermal analysis showed that the incorporation of f-MWCNTs has improved the thermal stability for the nanocomposites.

Development of HDPE/silicon nitride nanocomposites using HDPE-g-dibutyl maleate as compatibilizer

HDPE has been known for its dielectric properties. Thus in this study, attempt has been made to improve the overall performance of HDPE composites by blending silane treated silicon nitride (SN) with HDPE using HDPE-g-dibutyl maleate (HDPE-g-DBM) as compatibilizer. A small quantity of surface modified nanoclay has also been added in order to improve the mechanical properties. The flexural, wear and thermal properties of the composites were measured according to ASTM standards. The results reveal that, both silane modification of SN accompanied by nanoclay addition has led to the substantial enhancement in flexural strength and flexural modulus. In addition, compatibilization has further improved the mechanical properties showing 10% (w/w of SN) as optimal compatibilizer content. The wear results showed that, as SN content increased, the slide wear loss decreased. TGA analysis showed that, the addition of SN along with compatibilizer improved the thermal stability of the nanocomposites.

Fire Retardancy Characteristics and Mechanical Properties of High-Density Polyethylene/Ultrafine Fly Ash/MWCNT Nanocomposites

ABSTRACT Nanocomposites of high-density polyethylene along with ultrafine fly ash and acid-functionalized multiwalled carbon nanotubes have been developed. To enhance the interfacial adhesion, an epoxy-functionalized high-density polyethylene has been added, while the ultrafine fly ash has been surface modified using aminosilane-coupling agent. Improvement in mechanical properties using both ultrafine fly ash/multiwalled carbon nanotubes was seen and was further analyzed using micromechanical models. The addition of ultrafine fly ash and multiwalled carbon nanotubes together exhibited synergism leading to lowering of peak heat release rate. The nanocomposites showed enhanced thermal stability and lowered crystallinity percentage values of the high-density polyethylene phase due to improved interfacial interactions. GRAPHICAL ABSTRACT

HDPE nanocomposites using nanoclay, MWCNT and intumescent flame retardant characteristics

Nanocomposites of high density polyethylene (HDPE) along with nanoclay (NC), acid functionalized multiwalled carbon nanotubes (MWCNT) and pentaerythritol phosphate (PEPA) have been developed. In order to enhance the interfacial adhesion, HDPE grafted glycidyl methacrylate has been added to the composites. An improvement in mechanical properties and flammable characteristic for the nanocomposites has been observed using both nanoclay and MWCNT and was further analysed using micromechanical models.

Preparation of bio-nanocomposites of chitosan/thermoplastic starch reinforced with multiwalled carbon nanotubes

High performance bio-nanocomposites have been developed using crosslinked chitosan and thermoplastic starch along with acid functionalized multiwalled carbon nanotubes (f-MWCNT). The f-MWCNT loading was varied from 0 to 10%. A small amount of Dibutyl maleate has been added as a coupling agent, in order to improve adhesion between the biomaterials. The nanocomposites developed were characterized for flexural, wear, electrical and thermal properties as per ASTM standards. The composites containing f-MWCNTs exhibited enhanced flexural properties when compared with composites without f-MWCNTs. The wear results showed that, with the addition of f-MWCNTs the slide wear loss reduced slightly. The results revealed that, the resistivity of the nanocomposites decreased indicating the increase in conductivity of the nanocomposites.