E3: The melting index of different polymeric materialsObjectives: 1) Learn the operating mode of TWELVindex2) Determine the melting index of different polymeric materialsIntroduction: The melting index of different polymeric materials The melt flow is given by the weight of the extrudate in grams per 10 min [1]. Referring to Figure 1.1, the melt index measured according to condition E (190°C, 2160 g), which is the normal condition for polyethylene, is called "melt index (MI)". Polypropylene requires Condition-L (230°C, 2160 g) due to its high melting point, and the melt flow rate at Condition-L is called “Melt Flow (MF)”. Figure 1.1: Conditions deemed satisfactory for the listed material Melt index is a common measure used to characterize thermoplastic polymers [2]. Different types of polymers often report melt index under different conditions. Melt index values ​​are not always directly comparable between polymer types since polyethylene generally reports a melt index at 190°C while polypropylenes are generally reported at 230°C due to their different melting points. merger. There are standardized methods for melting index under ASTM and ISO, for example. example, ASTM D1238. Such standard methods specify the geometry and other constraints on the device used as well as the combinations of conditions. The device is essentially a narrow, vertical cylindrical cylinder equipped with a piston and a removable port (for cleaning) at the bottom, as in Figure 1.2. Figure 1.2: Schematic drawing of the fusion flow indexer. is placed on the piston to provide the prescribed force and therefore pressure on the piston, which drives the molten polymer through the orifice. Generally, polymer pellets are loaded into the barrel and allowed...... middle of paper ...... due to their molecular weight distribution and chain branching as well as their crystallinity.References :[1] Chan I. Chung. 2000. “Polymer Extrusion: Theory and Practice.” Germany: Hanser Verlag.[2] Ken. 2012. What is the fusion index? Accessed October 20, 2013. Available at: < http://www.vitaldose.com/blog/what-is-melt-index/>.[3] AB Mathur, IS Bhardwaj, AB Mathur. 2003. “Testing and Evaluation of Plastics.” New Delhi: Allied Publishers.[4] Muralisrinivasan Natamai Subramanian. 2013. “Additives and Testing for Plastics.” Canada: John Wiley & Sons.[5] Clive Maier, Thérèse Calafut. 1998. “Polypropylene: The Definitive User Guide and Data Book.” United States: William Andrew Inc.[6] T. Hatakeyama, Hyoe Hatakeyama. 2006. “Thermal Properties of Green Polymers and Biocomposites.” United States: Springer.[7] Barbara H. Stuart. 2008. “Polymer Analysis.” United States: John Wiley & Sons.