Determination of the melt flow index of plasticized polymer material by using plastometer mflow zwick. Melt flow index is a measure of the resistance to flow viscosity of the. Polymer melt flow during the filling process is assumed to be a nonisothermal flow of an incompressible, highly viscous, and nonnewtonian fluid with free surfaces. From melt flow index to rheogram welcome to ias fellows.
The weight of melt in grams flowing through the capillary in 10 minutes is the melt flow index. Some instruments can also calculate the shear rate, shear stress, and viscosity in. Influence of polymer melting point and melt flow index on the performance of ethylenevinylacetate modified bitumen for reducedtemperature application. Influence of polymer melting point and melt flow index on the performance of ethylenevinylacetate modified bitumen for reducedtemperature application a. Friction welding of dissimilar plasticbased material by metal powder reinforcement. Us4766200a us06945,784 us94578486a us4766200a us 4766200 a us4766200 a us 4766200a us 94578486 a us94578486 a us 94578486a us 4766200 a us4766200 a us 4766200a authority us united states prior art keywords melt flow mastication process polymer flow index prior art date 19840601 legal status the legal status is an assumption and is not a legal conclusion. The selection melting temperature was 180 oc and standard load is 5kg. Melt flow rate measures the rate of extrusion of thermoplastics through an orifice at a prescribed temperature and load.
Polymer blends have received a lot of attention in recent years due to the possibility of getting compounds with novel andor different properties through proper marriage of the properties of the respective monocomponents. In this study, the experiment was done by melt indexer machinemim which is a common equipment used for the melt flow index mfi or melt flow rate mfr. Dynisco melt flow indexers are recognized for testing the physical properties of polymers. Us4766200a process for improving the melt flow index of. Therefore, two polymers with the same mfi will not behave the same under any given processing conditions. The polymer melt viscosity is an important variable in the process and others because it effectively controls not just the way the process works but the strength of the final product. Influence of polymer melting point and melt flow index on. From lab to production, providing a window into the process. Melt flow rates of thermoplastics by extrusion plastometer1. This value is also commonly called the melt index, mi, or melt flow index, mfi. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic polymer. Comparison of melt flow index of propylene polymerisation. Pla, ldpe, polymer blends, melt viscosity, flow activation energy.
An effective method, proposed earlier by the authors, has been extended to generate normal stress difference versus shear rate curves from the melt flow index of polymer waste. The melt flow index mfi or melt flow rate mfr is a measure for the ease of. A knowledge of the complete flow curve or rheogram of a polymeric. Melt flow rate mfr when 20 kg weight used then mfr test is hlmi or high load melt index melt flow index mfi flow rate of pe obtained under 190 c and 2.
When using the test method for polymers other than. This instrument has been designed to determine the melt flow index property and other thermal processing properties of polymers. Melt flow index is a measure of the resistance to flow viscosity of the polymer melt at a given temperature under a given force for a predetermined period of time. Pdf melt rheology of polymer blends from melt flow index. Melt flow index of recycle abs for fused deposition. Different standardised conditions of extrusion temperatures and pressures are used for different types of polymer but, for. Rheograms of cellulosic polymers from the melt flow index.
Pdf rheograms of cellulosic polymers from the melt flow. Rheograms for engineering thermoplastics from melt flow index. Our processing instruments are used to prepare test specimens or evaluate the processability of materials. The melt flow index value allows for direct comparison of materials to each other and is a valuable tool for quality assurance. An effective method has been proposed to estimate the viscosity vs. Typical reactions for chain assembling are polyaddition continuous or step wise and condensation polymer ization polycondensation 1 figure 1.
A method for obtaining the melt flow index of the polymer blends at various compositions from the melt flow index of the individual components and the blend ratio has been suggested based on the. Data on the variation of melt viscosity over a wide range of shear rates and temperatures are necessary in the processing of cellulosic polymers. Standard test method for melt flow rates of thermoplastics by extrusion plastometer 1. Use of melt flow rate test in reliability study of. Pdf effect of the melt flow index and melt flow rate on. The addition of fillers to a polymer changes the melt. The viscosity in this region is known as the zero shear, or newtonian, viscosity ho. In general, a higher mfi indicates a lower material viscosity, and when comparing polymers of the same class, a lower melt flow rate corresponds to a. Using melt flow rate as a gauge for molecular weight of a.
However, because of the nature of nonnewtonian polymer melt flow the dimensionless numbers used to describe flow and heat transfer. It is defined as the mass of polymer, in grams, flowing in ten minutes through a capillary of a specific diameter and length by a pressure applied via prescribed alternative gravimetric weights for alternative prescribed temperatures. When the polymer flows, the polymer chains slip, or slide, over each other while. It provides a means of measuring flow of a melted material which can be used to differentiate grades as with polyethylene, or determine the extent of degradation. Polymers filled with extending fillers, such as calcium carbonate or talc, or with reinforcing fillers, such as glass fibers or mica, are increasingly being used in a number of applications. The sample can be in the form of virgin resin pellets or ground material from a finished thermoplastic product. Melt flow index values and molecular weight distributions. The mass of resin, in grams, that is extruded in 10 minutes equals the mfr, expressed in units of g10 min. Any attempt to use this instrument in any fashion other than its.
The data for polymer blends are compared with those obtained for simpler model systems. Melt viscosity is a constant at low shear rates or frequencies. Knowing the mfi of a polymer is vital to anticipating and controlling its processing. The inertia force is neglected in the momentum equation because the reynolds number of the polymer melt flow is low. The most commercially important polymer conversion processes involve meltprocessing methods in which the polymer is heated and made to flow. Measuring mass flow rate mfr and other polymer properties. Standard test method for melt flow rates of thermoplastics. Two or more existing polymers may be blended for various reasons. Melt flow indices are often listed on data sheets of thermoplastic materials. The corrections would be expected to vary for polymers of different flow characteristics. The data from this measurement must be interpreted cautiously, however, because polymers are usually processed under conditions that are far removed from those of the melt index. Quantifying relationships among the molecular weight. Effect of the melt flow index and melt flow rate on the thermal degradation kinetics of commercial polyolefins article pdf available in journal of applied polymer science 1265 december 2012.
Polymer manufacturers deliver high quality to meet ever changing enduse requirements. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic. The root variable is molecular weight, which determines both properties. Generally, higher mfi polymers are used in injection. Nadkarni polymer science and engineering group, chemical engineering division, national chemical laboratory pune india abstract. Investigation of melt flow index and impact strength of. Since molecular weight mw is the force that drives the performance of polymers, it turns out to be a highly beneficial number. Note 2 melt density is the density of the material in it molten state. Pdf determining the melt flow index of polypropylene. It is not to be confused with the standard density value of the material. From the rheological point of view, the blends are divided into three groups. Polymer processors usually correlate the value of mfi with the.
Astm d1238 standard test method for melt flow rates. The following polymers are generally categorized as engineering materials. Part i article pdf available in advances in polymer technology 61. This would be a useful tool for the plastics processor to assess the. The traditional melt index test astm d 1238 is widely used in the plastics industry to characterize polymer processability. Melt flow rate depends on molecular weight, additives, and other ingredients. One reason is to achieve a material that has a combination of the properties of the constituents. The governing equations are given below inoue and matsuoka 1994. Although frequently critiqued, melt flow rate mfr is an excellent measure of the polymer s relative average molecular weight.
Mfr and the melt volume flow rate mvr of thermoplastics3 3. Note 1 polymers having melt flow rates less than 0. Use of melt flow rate test in reliability study of thermoplastic. The mfr test quantifies the mass of thermoplastic resin that is extruded by an extrusion plastometer over a fixed time period specified as the mass in grams that would be extruded in 10 minutes under. Melt flow index is an assessment of average molecular mass and is an inverse measure of the melt viscosity. Melt flow index ratio 15 extensional flow 15 temperature effects 16 pressure effects 16 melt elasticity and memory 16 flow defects 17. Melt flow index, melt flow rate, astm d1238, iso 13. The value of melt flow index testing polymer solutions.
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