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Viscoelastic Functions: Effect of Various Parameters
Published in B. R. Gupta, Rheology Applied in Polymer Processing, 2023
Mishra et al.[127U] have reported on the mechanical and rheological properties of a thermoplastic polyolefine (TPO)/organoclay nanocomposites with reference to the effect of maleic anhydride modified polypropelene as a compatibilizer. Thermoplastic elastomer compositions based on uncured ethylene propylene dien terpolymer (EPDM) and polypropylene (PP) is referred as TPO. The compatibilizer not only enhances the intercalation of polymer chains inside the clay gallery but also changes the composition of the TPO/clay nanocomposites. The tensile modulus as well as storage modulus of the nanocomposite was substantially higher over their pristine counterpart. The increase in storage modulus in the melted state and decrease in terminal slope of nanocomposite confirms the strong interaction between clay platelet and polymer molecule in the melted state. The nanocomposites and their pritine counterpart show strong shear thining behaviour at the melted state.
Thermoplastic Rubbers via Dynamic Vulcanization
Published in Gabriel O. Shonaike, George P. Simon, Polymer Blends and Alloys, 2019
Most applications of TPO-V (ca. 40%) are in the automotive sector (airbag covers, axle sleeves, bumper fascia, under hood cables and hoses, sealings), where it replaces mostly thermoset rubbers and PVC. For bumpers, TPO-O grades are preferentially used. The second big market (ca. 30%) for TPO-V is building and construction (window glazing, weather seal, expansion joint, roofing membranes, etc.), followed by electric and electronic applications (ca. 15%; covering wire and cable jacketing, electric plugs). TPO-V is also gaining acceptance for medical goods, like tubes (dialysis, blood collection) and for sealing (safety needle sealing, medical stoppers). In case of technical rubber goods (seals, gaskets, bushings, etc.), TDVs are replacing conventional rubbers. Since their set properties are, however, inferior to those of the traditional rubbers, the replacement should be accompanied with some “redesign” (i.e., taking into consideration the property profile of the TDV) of the product. Forecasts for the consumption and applications, including replacement trends for TPEs, can be taken from recent reviews (78–80).
Electron Beam Processes
Published in Jiri George Drobny, Radiation Technology for Polymers, 2020
Thermoplastic elastomers based on polyolefins (TPO) are blends of PE or PP with EPDM elastomers wherein the elastomer is often cross-linked using thermochemical systems.205 TPOs more suitable for medical products with no chemical residuals can be made using EB processing to cross-link the elastomer portion in such an elastomer-plastic blend. The thermoplastic governs the melt transition, and thus the extrusion properties of TPOs. The radiation response of these materials is also governed by the choice of the thermoplastic. An example of an EB-cured blend of EPDM and polyethylene used is for fluid transmission tubing and electrical insulation.206
Synthesis of multi-walled carbon nanotubes using tire pyrolysis oil as a carbon precursor by spray pyrolysis method
Published in Inorganic and Nano-Metal Chemistry, 2018
B. Parasuram, S. Sundaram, C. Sathiskumar, S. Karthikeyan
Disposal of waste scrap tires is a major environmental and economic issue.[1] It was estimated that approximately more than 1.5 tones of tires were produced worldwide each year, which eventually ends up as waste tires.[2] The negative impacts caused by disposal of waste tires in landfills on both environment and humans can be minimized by recovering constituent chemicals and energy content from these tires using available technologies.[3] From the total mass, 30% of the waste tires can be reused and recycled as new rubber products, playgrounds, sports surfacing and rubber-modified asphalt.[4] For the last few decades, researchers had been looking for various ways to overcome the problems of such large quantities of waste tires. They had been of high interest in alternative recycled process for waste tires.[5] One of the alternative technologies was pyrolysis. Pyrolysis offered an environmental attractive method to decompose wide variety of waste tires. Pyrolysis is nothing but the thermal degradation (absence of oxygen) of the waste tires at a typical pyrolysis temperature of 400°C to produce oil, gas, and char. Tire pyrolysis oil (TPO) was a chemically complex mixture of aliphatic, aromatic, heteroatom, and polar fraction. TPO may be used directly as a fuel, added to petroleum refinery stocks, upgraded using catalyst to a premium grade fuel, or used as a chemical feedstock. Carbon nanotubes (CNTs) are very promising nanomaterials thanks to their exclusion properties.[6] CNTs have outstanding electrical, thermal, and mechanical properties which make them an interesting material for application in nanoelectronics sensors and field emission.[7] The currently existing methods for CNT production are electric arc discharge method, laser ablation method, chemical vapor deposition (CVD), flame synthesis, and the solar energy route. Among these methods, CVD seems to be the most promising and low-cost process.[8] Several papers had been published and described a simple routine for synthesizing low-cost CNT arrays in large scale from petroleum-based precursors such as benzene, xylene, and hexane. This carbon precursor would not be sustainable due to an unstable supply of oil resources. From the CNT research groups were advised, it is better to choose a hydrocarbon precursor (starting materials) from unconventional and waste material, such as botanical hydrocarbon for the synthesis of CNTs.[9,10] In the present work, the fractions of TPO with boiling point ranging from 45 to 205°C (low boiling point liquid) were chosen as precursor for the synthesis of MWNTs on quartz substrate using ferrocene as a catalyst at 950°C.