MIT-World Peace University (MIT-WPU) is a top educational institute located in Pune, India. It is recognized within&nbsp;UGC under Government of Maharashtra Act No. XXXV 2017.&nbsp;

It is part of the MIT group of institutions (established in 1983) which covers 10+ campuses across India and has more than 50,000+ students enrolled across various disciplines at a given point of time. The institute houses 15 schools ranging from Engineering &amp; Technology, Design, Pharmacy, Commerce, Governance among others. It offers undergraduate, postgraduate and PhD programs among different disciplines.&nbsp;

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MIT World Peace University

School of Polymer Engineering

Polypropylene (PP) is one of the fastest growing thermoplastic polymers in the world, second only to polyethylene. This is primarily due to its excellent balance of physical and chemical properties at a lower cost. PP however possesses low melt strength on account of its linear structure and hence is not easily amenable to processing techniques that involve free surface stretching deformations like thermoforming, blow molding and extrusion film casting. One way to enhance the melt strength of PP is to incorporate long chain branches in its molecular architecture. The present study focuses on the impact of rheology of linear and branched PP on their thermoforming characteristics. Two grades each of linear and long chain branched (LCB) PP homopolymer and impact copolymer (ICP) were used. It was observed that the LCB-PP homopolymer and LCB-ICP showed higher flow activation energy, reduced value of loss tangent and nearly equal frequency dependence of storage and loss moduli in shear rheology. Also, a strong strain hardening behavior was displayed in extensional rheology by the LCB grades. Plug assist thermoforming experiments were carried out to assess the effect of long chain branching on surface strain and thickness distribution for axisymmetric cups of two draw ratios. Biaxial surface strain maps of the formed cups were quantified using Grid Strain Analysis (GSA). Thermoformed cups made from LCB-PP homopolymer and LCB-impact copolymer showed lower surface strain and overall higher thickness as compared to cups made from their linear counterparts, which is in accordance with what might be expected from their rheology.

Engineering and Technology

Fulltext

International Polymer Processing

Study of Rheology and Plug Assist Thermoforming of Linear and Branched PP Homopolymer and Impact Copolymer

Polypropylene (PP)-Flyash (FA) composites containing natural banana fiber (NF) treated by Maleic anhydride and NaOH are reported here. Mechanical properties such asflexural modulus and impact strength were improved considerably which were maximum for 20% fly ash filled PP-NF treated composites. There is extensive nucleation of theα crystalline phase of PP in presence of the additives. This changed to mixed α phase with slight β content in presence of FA and treated NF as confirmed by XRD and DSC. The results on the mechanical properties have been explained on the basis of structure development of PP in presence of fly ash and treated NF. The results have also been analyzed with the help of different models for filled polymer composites and using rule of mixtures of two composites to form final ternary hybrid composite. Some agreement is found if a factor is introduced for redistribution of fibers due to added FA as third component. However, the synergistic behavior at certain composition can be explained on the basis of crystalline structure and nucleation due to the additives.

World University root node

Mater. Res. Express

Structure, mechanical and thermal properties of polypropylene based hybrid composites with banana fiber and fly ash

This paper explores the application of the cooling techniques and Moldex3D software for simulation of cooling system in the injection molding process. The effect of cooling systems as the most important factors in optimization of plastic injection molding. Optimization of cooling system plays a significant role in the quality, efficiency, and the cost effective manufacturing. The importance of shape, type, and the location of cooling channels using the Moldex3D software and good results are achieved. Using numerical simulation tools or combination of analytical and numerical simulation approach is one of the intelligent choices applied to modern mold cooling design. Keywords - Injection Molding, Moldex3D Software, Optimization of Cooling Channels.

International Journal of Mechanical and Production Engineering

Optimization of cooling system using simulation software in injection molding

Polybenzoxazine/epoxy-fumed silica filled composites have been prepared by blending benzoxazine with epoxy (EP) in presence of fumed silica (FS). It has been observed that the thermal stability of the composites increased with increasing amount of fumed silica in the composite composition. Mechanical properties of the composites have been investigated by using tensile and flexural tests. Composites consist of 4 wt% fumed silica in the polymeric matrices, exhibited higher tensile and flexural strength than neat polybenzoxazine, epoxy and their polymeric metrics blend. Prepared composites possess better mechanical and thermal properties than the neat polymers, as well as easy processibilty which can make them good candidates to prepare of complex reinforced structures for various industrial applications.

Materials Research Express

Effect of fumed silica on properties and morphology of polybenzoxazine/epoxy composites

Recycling of plastics is very much hindered due to the process of segregation and sorting of individual polymer and also lack of compatibility between the different polymers. There is no single compatibilizer which can be effective for different pairs of polymer. If one could develop a multifunctional compatibilizer (MFC) that can be effective for a various range of polymers, the mixed plastics waste can be processed as such with minimal sorting/segregation. There are a number of reports on compatibilizer for specific pairs of polymer blends but there are practically no reports on single compatibilizer which works for different pairs of polymers. In the present studies, we have investigated the possibility of introducing different functional groups on a single polymer chain by chemical grafting. This multifunctional polymer has been used as compatibilizer for polypropylene blend with polymethyl methacrylate (PMMA) and ethylene vinyl acetate (EVA). © 2018, Springer Nature Singapore Pte Ltd.

Materials Horizons: From Nature to Nanomaterials

Multifunctional Compatibilizer for Polypropylene Blends with PMMA and EVA

The heat transfer co-efficient (HTC) was measured in nanofluids made from ethylene glycol water mixture dispersed with different amounts of graphite nanoparticles (GRNP) at different flow rates (Reynolds number Re = 50 to 800) and temperatures range between 10 to 85 °C. It was observed that the HTC was highly dependent on the Re with two regimes. HTC was found to follow the power law of the type (HTC) = A (Re)χ where the exponent χ was dependent on Re range, composition and temperature. In the high Re regime, the exponent was of the order of 0.5 while at low Re regime (Re < 150) the χ value was 0.85 to 0.92. The HTC at low Re values could be correlated with the thermal conduction process and Brownian motion, while at high Re, random motion could be prevailing. The results have been compared with the reported data for carbon nanotubes (CNT) for which also the exponent was much more than 0.333 which is indicated in the standard Sieder-Tate equation. Thus, the overall variation of HTC with Re appears to be HTC= A Reχ where χ assumes values depending on the regimes of Re viz. low, intermediate and high Re with χ ≈ 0.92, 0.3 < χ <0.5 and χ ≥ 0.85 respectively.

School of Mechanical Engineering

Journal of Nanofluids (USA)

Power Law Variation of Heat Transfer Coefficient with Reynolds Number in Nanofluids Containing Graphite and Carbon Nanotubes Nanoparticles

Rigid and plasticized PVC is used extensively in a variety of industries like construction, packaging sheet and film, electrical, automotive parts, furniture equipment, clothing, footwear, etc. In recent years, natural biobased materials are being explored for plasticizers for PVC. The present work focuses on the development of different epoxidized soybean oil (ESBO) plasticized PVC formulations in the presence of calcium/zinc stearates and beta-diketone stabilizer such as dibenzoylmethane (DBM). The DBM which has dual property of a UV stabilizer and heat stabilizer was varied from 0 to 10 phr. The PVC films were prepared and analyzed in terms of dehydrochlorination studies. The above PVC films were exposed for 100&nbsp;h in the accelerated QUV weathering, and the characterization of the exposed products was carried out in terms of mechanical and thermal properties and dehydrochlorination. This ternary system hinders the degradation process and decreases the initial rate of dehydrochlorination. The success of the novel beta-diketones stabilizers can meet higher performance and longer service life of epoxidized soybean oil plasticized PVC films in the presence of zinc/calcium stearates. This will ultimately lead to a positive influence on the environment.

Advances in Polymer Sciences and Technology

Stabilization Studies of Epoxidized Soybean Oil Plasticized PVC Films in the Presence of Beta-Diketone Additives

Utilization of waste from tire industry as reclaimed tire rubber (RTR) by formation of blends with high density polyethylene (HDPE) is great area to be focused. Enhancement of properties by the addition of triallyl cyanurate (TAC) as a co-agent with 1%, 3% and 5% to blend of HDPE 50 wt% and RTR 50 wt% in presence of gamma irradiation curing were investigated. Specifically, mechanical and thermal properties were studied as a function of amount of TAC and gamma irradiation dose in range of 50–200 kGy. The resultant blends were evaluated for the values of impact strength, gel content, thermal stability, tensile properties, rheological properties and morphological properties with increasing irradiation dosage and TAC loading. The mechanical properties tensile strength, hardness, impact strength of blend containing 3% of TAC were substantially increased with increasing irradiation dosage up to 150 KGy. Rheological analysis has shown increase in viscosity with increase in TAC loading up to 3% and 150 KGy irradiation dosages. 3% loading of TAC lead to better set of properties with150 KGy gamma irradiation dosage.

Radiation Physics and Chemistry

Influence of triallyl cyanurate as co-agent on gamma irradiation cured high density polyethylene/reclaimed tire rubber blend

Powder-mixed polypropylene (PP)–graphite binary composites exhibit an electrical percolation threshold at 10 wt% graphite signifying insulator-semiconductor transition. Three conducting fillers such as carbon black (CB), sonicated expanded graphite (s-ExGr), and carbon nanofiber (CNF) are mixed with PP-7 wt% graphite binary composites. The electrical percolation threshold has been found to have inverse relation to the aspect ratio of second conducting fillers in hybrid composites. The aspect ratio of second conducting fillers varies in the order CB < ExGr < CNF. The electrical percolation threshold is found to vary for the hybrid composites as 2.2 wt% for CB addition, 0.75 wt% for ExGr addition, and 0.2 wt% for CNF addition in the PP-7 wt% graphite binary composites. When the aspect ratio of second conducting fillers increases, they reduce the barrier for the charge transport. The second conducting fillers occupy the interspace of graphite and alternating current studies show that the effective dielectric constant increases with the concentration of second conducting filler in the hybrid composites. The composites are characterized by transmission electron microscopy and scanning electron microscopy. Melt-crystallized PP-7 wt% graphite-CNF composites exhibit higher percolation threshold due to decrease in the polymer viscosity which increases the interparticulate distance.

Journal of Thermoplastic Composite Materials

Polypropylene based conducting nanocomposites: Effect of aspect ratio of secondconducting filler on the electrical percolation

Polyphenylene sulfide (PPS)-expanded graphite (ExGr) conducting nanocomposites have been prepared by powder mixing and in situ polymerization routes after sonicating ExGr particles in acetone. Synthesized PPS has been used to make powder mixed composites. The powder mixed composites exhibit a percolation threshold of 3 wt% due to the formation of graphite nanosheets. When PPS-ExGr composites are prepared by in situ polymerization route, very low electrical percolation threshold less than 0.5 wt% ExGr is obtained. The low percolation threshold obtained is attributed to better dispersion of ExGr nanosheets in the polymer matrix when compared to powder mixed composites. The synthesized PPS has been characterized by X-ray diffraction, differential scanning calorimetry, and infrared spectroscopy. The formation of graphite nanosheets has been confirmed by transmission and scanning electron microcopy analysis.