The data for polymer blends are compared with those obtained for simpler model systems. The traditional melt index test astm d 1238 is widely used in the plastics industry to characterize polymer processability. Dynisco melt flow indexers are recognized for testing the physical properties of polymers. Since molecular weight mw is the force that drives the performance of polymers, it turns out to be a highly beneficial number. The selection melting temperature was 180 oc and standard load is 5kg. Influence of polymer melting point and melt flow index on the performance of ethylenevinylacetate modified bitumen for reducedtemperature application. One reason is to achieve a material that has a combination of the properties of the constituents. Knowing the mfi of a polymer is vital to anticipating and controlling its processing. This value is also commonly called the melt index, mi, or melt flow index, mfi. Our processing instruments are used to prepare test specimens or evaluate the processability of materials.
However, because of the nature of nonnewtonian polymer melt flow the dimensionless numbers used to describe flow and heat transfer. The value of melt flow index testing polymer solutions. A knowledge of the complete flow curve or rheogram of a polymeric. Different standardised conditions of extrusion temperatures and pressures are used for different types of polymer but, for. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic. 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. Quantifying relationships among the molecular weight. When the polymer flows, the polymer chains slip, or slide, over each other while. Pdf effect of the melt flow index and melt flow rate on. Part i article pdf available in advances in polymer technology 61. The melt flow index value allows for direct comparison of materials to each other and is a valuable tool for quality assurance. Pdf rheograms of cellulosic polymers from the melt flow. It is not to be confused with the standard density value of the material. 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.
Pdf determining the melt flow index of polypropylene. The governing equations are given below inoue and matsuoka 1994. 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 values and molecular weight distributions. 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. 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. The sample can be in the form of virgin resin pellets or ground material from a finished thermoplastic product. This instrument has been designed to determine the melt flow index property and other thermal processing properties of polymers. An effective method has been proposed to estimate the viscosity vs. The root variable is molecular weight, which determines both properties. Us4766200a process for improving the melt flow index of. 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.
Polymer manufacturers deliver high quality to meet ever changing enduse requirements. Nadkarni polymer science and engineering group, chemical engineering division, national chemical laboratory pune india abstract. More than just a quality control rheological parameter. Typical reactions for chain assembling are polyaddition continuous or step wise and condensation polymer ization polycondensation 1 figure 1. Melt viscosity is a constant at low shear rates or frequencies. Standard test method for melt flow rates of thermoplastics by extrusion plastometer 1. Measuring mass flow rate mfr and other polymer properties. Use of melt flow rate test in reliability study of thermoplastic. 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. Generally, higher mfi polymers are used in injection. Influence of polymer melting point and melt flow index on the performance of ethylenevinylacetate modified bitumen for reducedtemperature application a. When using the test method for polymers other than.
Astm d1238 standard test method for melt flow rates. Note 2 melt density is the density of the material in it molten state. Melt flow index is a measure of the resistance to flow viscosity of the. Polymer processors usually correlate the value of mfi with the.
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. Melt flow index of recycle abs for fused deposition. The melt flow index mfi or melt flow rate mfr is a measure for the ease of. The addition of fillers to a polymer changes the melt. Comparison of melt flow index of propylene polymerisation. Some instruments can also calculate the shear rate, shear stress, and viscosity in. Automatically timed flow rate measurement may be performed. Influence of polymer melting point and melt flow index on. The most commercially important polymer conversion processes involve meltprocessing methods in which the polymer is heated and made to flow. The inertia force is neglected in the momentum equation because the reynolds number of the polymer melt flow is low. From melt flow index to rheogram welcome to ias fellows.
Although frequently critiqued, melt flow rate mfr is an excellent measure of the polymer s relative average molecular weight. Two or more existing polymers may be blended for various reasons. 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. Investigation of melt flow index and impact strength of. 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. 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.
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. Friction welding of dissimilar plasticbased material by metal powder reinforcement. Use of melt flow rate test in reliability study of. Melt flow rate depends on molecular weight, additives, and other ingredients. Note 1 polymers having melt flow rates less than 0. Rheograms for engineering thermoplastics from melt flow index.
The weight of melt in grams flowing through the capillary in 10 minutes is the melt flow index. The mass of resin, in grams, that is extruded in 10 minutes equals the mfr, expressed in units of g10 min. Data on the variation of melt viscosity over a wide range of shear rates and temperatures are necessary in the processing of cellulosic polymers. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic polymer. 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. Pdf melt rheology of polymer blends from melt flow index. Although pom fg40u01 cf2001 is a melt blown grade copolymer, it has a very low melt flow rate of 40g10 min at 230oc according to astm d1238, which indicates that the resin has a high average molecular. The viscosity in this region is known as the zero shear, or newtonian, viscosity ho.
Mfr and the melt volume flow rate mvr of thermoplastics3 3. Therefore, two polymers with the same mfi will not behave the same under any given processing conditions. 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. Melt flow index ratio 15 extensional flow 15 temperature effects 16 pressure effects 16 melt elasticity and memory 16 flow defects 17. Standard test method for melt flow rates of thermoplastics. This would be a useful tool for the plastics processor to assess the.
Determination of the melt flow index of plasticized polymer material by using plastometer mflow zwick. The corrections would be expected to vary for polymers of different flow characteristics. Rheograms of cellulosic polymers from the melt flow index. Melt flow rate measures the rate of extrusion of thermoplastics through an orifice at a prescribed temperature and load. 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. Melt flow indices are often listed on data sheets of thermoplastic materials.