Elucidating the Coir Particle Filler Interaction in Epoxy Polymer Composites at Low Strain Rate

Rahul Kumar,Sumit Bhowmik 한국섬유공학회 2019 Fibers and polymers Vol.20 No.2

Addressing the growing environmental issues and diverse range of applications, the present work is focused on the development of high potential ‘agro-waste’ such as ‘coir filler’ reinforced epoxy composite and evaluation of its critical mechanical properties under diverse constraints. The produced composite material is subjected to a tensile test with variable strain rate, fracture test, impact test and thermogravimetric analysis to assess its applicability in diverse loading and temperature environment. The experimental results display the complementary effect of coir fillers in improving the mechanical properties of the composite by two to four times as compared to neat epoxy and other bio-fibre/filler based composite materials. The increased tensile and flexural strength with filler addition confirms the evident interaction and load transfer capability of infused coir particle fillers in the epoxy matrix. The rate of crack initiation and propagation in the tensile test seems to be extremely affected by the strain rate variation and at higher crosshead speed, the fracture initiated early due to the singularity existed at the crack tip. The highest value of tensile stress and Young’s modulus for the developed composite material is observed at the crosshead speed of 2 mm/min. The fracture properties is observed to be maximum for 5 wt. % filler loading and the principal mechanism of fracture failure is crack pinning. This study will be able to open new insights and establish the probable application of the low-cost agro-byproduct in the engineered value added bio-based composite material.

Electromagnetic Interference Reflectivity of Nanostructured Manganese Ferrite Reinforced Polypyrrole Composites

Himel Chakraborty,Sumit Chabri,Nandagopal Bhowmik 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.6

Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.

Electromagnetic Interference Reflectivity of Nanostructured Manganese Ferrite Reinforced Polypyrrole Composites

Chakraborty, Himel,Chabri, Sumit,Bhowmik, Nandagopal The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.6

Nano-size manganese ferrite reinforced conductive polypyrrole composites reveal a core-shell structure by in situ polymerization, in the presence of dodecyl benzene sulfonic acid as the surfactant and dopant, and iron chloride as the oxidant. The structure and magnetic properties of manganese ferrite nano-fillers were measured, by using X-ray diffraction and vibrating sample magnetometer. The morphology, microstructure, and conductivity of the composite were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and four-wire technique. The microwave-absorbing properties of composites reinforcement dispersed in resin coating with the coating thickness of 1.2 nm were investigated, by using vector network analyzers, in the frequency range of 8~12 GHz. A reflection loss of -8 dB was observed at 10.5 GHz.

Effect of Space Charge Density and High Voltage Breakdown of Surface Modified Alumina Reinforced Epoxy Composites

Himel Chakraborty,Arijit Sinha,Sumit Chabri,Nandagopal Bhowmik 한국전기전자재료학회 2013 Transactions on Electrical and Electronic Material Vol.14 No.3

The incorporation of 90 nm alumina particles into an epoxy matrix to form a composite microstructure is described in present study. It is shown that the use of ultrafine particles results in a substantial change in the behavior of the composite, which can be traced to the mitigation of internal charges when a comparison is made with conventional Al2O3 fillers. A variety of diagnostic techniques have been used to augment pulsed electro-acoustic space charge measurement to provide a basis for understanding the underlying physics of the phenomenon. It would appear that,when the size of the inclusions becomes small enough, they act cooperatively with the host structure and cease to exhibit interfacial properties. It is postulated that the Al2O3 particles are surrounded by high charge concentrations. Since Al2O3 particles have very high specific areas, these regions allow limited charge percolation through Al2O3 filled dielectrics. The practical consequences of this have also been explored in terms of the electric strength exhibited. It would appear that there was a window in which real advantages accumulated from the nano-formulated material. An optimum filler loading of about 0.5 wt.% was indicated.

Punica Granatum Fibers as Potential Reinforcement of Composite Structures

Divya Zindani,Santosh Kumar,Saikat Ranjan Maity,Sumit Bhowmik 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

In the present work, punica granatum (Punica granatum L) straw discarded from the punica granatum cultivationhas been explored for potential reinforcement to form green polymeric composites. To adjust the lignin content, the punicagranatum straw fibers (PGF) were dissolved in an aqueous solution of sodium bicarbonate (10 %w/w) for different duration(1 day, 5 days and 10 days) at room temperature. The statistical parmeter associated with the fiber morphology wasdetermined for different fiber conditions. The relationship between tensile properties and fiber transverse dimensions wasinvestigated through mathematical model. Moreover, the bio-epoxy composites reinforced with punica granatum straw fiberswere fabricated and characterized for static mechanical properties. The optimal composite composition was determined usingTOmada de Decisao Interativa Multicriterio (TODIM) methodology. PGF-5D reinforced green composite with 30 wt% fiberloading was identified as the optimal composition. Finally, micromechanics evaluation was carried out to quantify the criticalparameters playing a major role in controlling the structural-property relationships of the fabricated composites.

Effect of Space Charge Density and High Voltage Breakdown of Surface Modified Alumina Reinforced Epoxy Composites

Chakraborty, Himel,Sinha, Arijit,Chabri, Sumit,Bhowmik, Nandagopal The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.3

The incorporation of 90 nm alumina particles into an epoxy matrix to form a composite microstructure is described in present study. It is shown that the use of ultrafine particles results in a substantial change in the behavior of the composite, which can be traced to the mitigation of internal charges when a comparison is made with conventional $Al_2O_3$ fillers. A variety of diagnostic techniques have been used to augment pulsed electro-acoustic space charge measurement to provide a basis for understanding the underlying physics of the phenomenon. It would appear that, when the size of the inclusions becomes small enough, they act cooperatively with the host structure and cease to exhibit interfacial properties. It is postulated that the $Al_2O_3$ particles are surrounded by high charge concentrations. Since $Al_2O_3$ particles have very high specific areas, these regions allow limited charge percolation through $Al_2O_3$ filled dielectrics. The practical consequences of this have also been explored in terms of the electric strength exhibited. It would appear that there was a window in which real advantages accumulated from the nano-formulated material. An optimum filler loading of about 0.5 wt.% was indicated.