E3: The Melt Flow Rate of Different Polymeric Materials
Objectives:
1) To learn the operating procedure of TWELVindex
2) To determine the melt flow rate of different polymeric materials
Introduction:
Melt flow index is given by the weight of the extrudate in gram per 10 min [1]. Referring to Figure 1.1, the melt flow index measured according to Condition-E (190°C, 2160g) which is the normal condition for polyethylene is called “Melt Index (MI)”. Polypropylene requires Condition-L (230°C, 2160g) because of its high melting point, and the melt flow index at Condition-L is called “Melt Flow (MF)’.
Figure 1.1: Conditions that found satisfactory for the material listed
Melt index is a common measurement used to characterize thermoplastic polymers [2]. Different polymer types often report melt index at differing conditions. Melt index values are not always directly comparable between polymer types since polyethylene typically report melt index at 190°C whereas polypropylenes are typically reported at 230°C due to their different melting points.
There are standardized methods for melt index under ASTM and ISO, for 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 an upright, narrow cylindrical barrel fitted with a plunger and a removable (for cleaning) orifice at the bottom as in Figure 1.2.
Figure 1.2: Schematic drawing of the Melt Flow Indexer.
The barrel is temperature controlled and a defined weight is placed on the plunger to provide the prescribed force and thus pressure on the plunger, which drives the polymer melt through the orifice. Typically, polymer pellets are loaded into the barrel and allowed...
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...s due to their molecular weight distribution and chain branch as well as their crystallinity.
References:
[1] Chan I. Chung. 2000. ‘Extrusion of Polymers: Theory and Practice’. Germany: Hanser Verlag.
[2] Ken. 2012. What is Melt Index? Viewed on 20 October 2013. Available from: < http://www.vitaldose.com/blog/what-is-melt-index/>.
[3] A. B. Mathur, I. S. Bhardwaj, A. B. Mathur. 2003. ‘Testing and Evaluation of Plastics’. New Delhi: Allied Publishers.
[4] Muralisrinivasan Natamai Subramanian. 2013. ‘Plastics Additives and Testing’. Canada: John Wiley & Sons.
[5] Clive Maier, Theresa Calafut. 1998. ‘Polypropylene: The Definitive User's Guide and Databook’. USA: William Andrew Inc.
[6] T. Hatakeyama, Hyoe Hatakeyama. 2006. ‘Thermal Properties of Green Polymers and Biocomposites’. USA: Springer.
[7] Barbara H. Stuart. 2008. ‘Polymer Analysis’. USA: John Wiley & Sons.
There are many internal parts to the injector. Starts with a barrel then moves down to a plunger then there is a check valve, below that is a spacer with the nozzle springs inside of it, lastly is the nozzle. All of these parts have specific and unique jobs. Nozzle has a needle in it that works kind of like a piston that once the pressure build up the needle forces forward and sprays fuel. There is a spacer above the nozzle with the nozzle springs that force the needle down. Above the spacer is a check valve, the check valve allows the right amount of fuel into the nozzle. The plunger and barrel are located above the check valve. It has a spring on the plunger that has to hold resistance of the pressure until it reaches the correct amount before it will let the injector fires. There is two internal o-rings one that is around the plunger and one that sets between the nut and body.
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Piringer, O., & Baner, A. (2008). Plastic packaging: interactions with good and pharmaceuticals. New York: Wiley-VCH.
low current to melt. Below is a graph of the results I expect to get.
Melting Point Determination of Alum 1. 0.5 g of dry alum was crushed with the mortar and pestle, and then the crushed alum was packed to the bottom the capillary tube. The alum measured about 0.5 cm from the bottom of the tube. Then the tube was fastened to the thermometer with the rubber band, and the thermometer was fastened to the ring stand with the universal clamp. 2.
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Gerngross, Tillman U. and Steven C. Slater. "How Green are Green Plastics?" Scientific American. August 2000:1-7.
The Web. The Web. 28 Apr. 2014. The 'Standard' of the 'Standard'. Metal Melting 101 - How To.
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