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 of the plastic as a result of molding. Melt flow rates of thermoplastics by extrusion plastometer1. Both melt flow and rheology tests can be very helpful tools for qc monitoring and development of polymers. Knowing the mfi of a polymer is vital to anticipating and controlling its processing. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic polymer.
Qc652s melt flow index astm d1238, astm d3364, iso 13. It is found that the mfi and impact strength of rotomoulded product increases. Plastics testing lab rheology lab melt flow testing melt flow index mfi melt flow rate mfr volumetric flow rate q plastic melt density. Injection molding fractional melt index, high density polyethylene materials laren d. Melt flow rate testing part 4 reprinted with permission materials know how by michael sepe from michael p.
Of those that do, most dont understand why they are doing it or what they are measuring. A number in parentheses indicates the year of last. The melt flow index mfi is a measure of the ease of flow of the melt of a thermoplastic. Melt flow tests are a simple method of characterizing the flow properties of a plastic melted mass. Standard test method for melt flow rates of thermoplastics by extrusion plastometer, iso13. Melt flow system the 6mba is the basic model offered within the rayran range of melt flow indexers. Part i article pdf available in advances in polymer technology 61. Different standardised conditions of extrusion temperatures and pressures are used. From melt flow index to rheogram welcome to ias fellows. The 4601 melt flow indexer is an affordable and easytouse tabletop instrument that tests the melt flow resistance mfr of a wide range of thermoplastics.
Melt flow index tester, manufacturers suppliers of melt. Pertaining to materials typically used in geosynthetics, this test follows astm d1238 or iso 013. The melt flow index mfi, also known as the melt flow rate mfr, of a resin is a materials property test used in the plastics industry. 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. Scanning electron microscope image obtained from polypropylene. Because the viscosity of a polymer varies with flow rate, or shear rate, a complete characterization of viscosity must allow for measurements at multiple shear. The result is expressed in grams per 10 minutes g10 min. The model is used to determine melt flow index grams 10 minutes, melt volume rate cu. Melt flow index tester is a consistent tool useful for checking the flow properties of molten plasticsresins. Provision is made for calculation of melt volumeflow rate as well as melt mass flow rate. The melt flow rate mfr, originally called melt flow index or melt index, is a measure of the ease of flow of the melt of a thermoplastic polymer.
Determination of melt mass flow rate mfr and melt volume. Standard test method for melt flow rates of thermoplastics by extrusion plastometer1 this standard is issued under the. Shoup, chevron phillips chemical company lp abstract when injection molding high density polyethylene hdpe, typical melt index of the product used ranges from about 2. Aug 26, 20 melt flow rate testing part 2 to fully appreciate the strengths and weaknesses of the meltflowrate mfr test it is important to know something about the way the test is performed. Similarly, the test conditions of mfi measurement is normally expressed in kilograms rather than. Note 2 melt density is the density of the material in it molten state. The melt flow index only tests the material at one shear stress, and temperature.
Melt flow indexer the melt flow indexer is an affordable tabletop instrument that tests the melt flow resistance mfr of a wide range of thermoplastics. Injection molding fractional melt index, high density. The tester conforms to all national and international melt flow resistance standards, including bs en iso 13 and astm d1238. 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. Melt flow rate testing for moisture sensitive materials solution. A flow rate test is a measure of a polymers mass flow rate grams extruded in 10 minutes using a particular orifice under specified conditions of temperature and load. Standard test method for melt flow rates of thermoplastics by extrusion plastometer 1. A useful measure of the shear stressshear rate relationship flow parameter can be made by measuring the samples mfr at standard load and at a higher load. The value of melt flow index testing polymer solutions. Using standard test procedure and conditions to perform mfi test on plastic granules is the best way to determine the physical as well as chemical properties of the material. Impact tests and melt flow property are performed on the rotationally molded parts. Melt flow index is an assessment of average molecular mass and is an inverse measure of the melt viscosity. Ceast melt flow testers range from systems that perform a simple manual test procedure to semiautomated testing systems performing multiple weight tests.
Polyox watersoluble resins melt flow test procedure. The demands placed on the extrusion plastometer vary according to which processing stage in the plastics industry is involved. Plastics determination of the melt massflow rate mfr and the melt volumeflow rate mvr of thermoplastics part 1. The mfi is the melt flow index, an empirical measure of melt viscosity used by moulders, and inversely related to molecular weight. Melt flow rate testing part 2 to fully appreciate the strengths and weaknesses of the meltflowrate mfr test it is important to know something about the way the test is performed.
This presentation is designed to be an informative introduction and guide to melt flow test, and to assist with troubleshooting inconsistencies in results. The sample consists of a strand produced by extrusion of the polyethylene in accordance with test method d1238, condition 1902. While melt flowrate testing is not extremely difficult, and the equipment is not very costly, few. Melt flow rate measures the rate of extrusion of thermoplastics through an orifice at a prescribed temperature and load. The melt flow index mfi is the measure of how many grams of polymer pass through a standardized capillary under a standard load over 10 minutes. Astm d1238 standard test method for melt flow rates of. Determination of melt mass flow rate mfr and melt volume flow rate mvr iso 131, 2 and astm d1238 extrusion plastometers provide standard values for the melt index mfr and volume index mvr of filled and unfilled thermoplastics to iso 131 and 2, astm d1238. Astmd1238 standard test method for melt flow rates of.
Melt flow index, melt flow rate, astm d1238, iso 13. Both measure the same property, but slight procedural and equipment differences can yield different results. Iso 131991 determination of the meltmass flow rate mfr and the melt volumeflow rate mvr of thermoplastics3 3. Investigation of melt flow index and impact strength of. The instron melt flow testers are specifically designed for easy and accurate measuring of the melt massflow rate mfr and the melt volumeflow rate mvr. Iso 13 determination of the meltmass flow rate mfr and the melt volumeflow rate mvr of thermoplastics3 3. The test conditions normally used for thermoplastics are listed in annex a. Use of melt flow rate test in reliability study of. Friction welding of dissimilar plasticbased material by metal powder reinforcement. Standards can be obtained from appropriate standard authorities. Plastic testing instruments melt flow index tester. 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 prescribed temperature and mechanical load conditions. The shear rates encountered in the pipes of moulding machines is typically above 10 3 sec. Greater control on timetemperature history occurring during test.
Determination of the melt massflow rate mfr and melt volumeflow rate mvr of thermoplastics. Astm d 1238 melt flow rates of thermoplastics by extrusion plastometer iso 13 plastics determination of the melt massflow rate mfr and the melt volumeflow rate mvr of thermoplastics. The sample can be in the form of virgin resin pellets or ground material from a finished thermoplastic product. This test method is widely used, especially in quality assurance and goods inwards testing. Presto stantest understands the need for measuring mfi of polymer granules and offers a highquality melt flow index tester. Machines that determine flow rate are generally called melt indexers.
Note 1 polymers having melt flow rates less than 0. It is generally used as an alternative to procedure b on samples having melt flow rates greater than 75 g10 min. Flow rate 600t x weight of extrudate t time of extrudate in seconds. Experimental procedure summary approximately 6 to10 grams of polyethylene is loaded into the barrel of the melt flow plastometer. Standard test method for melt flow rates of thermoplastics. Pdf determining the melt flow index of polypropylene. Generally, higher mfi polymers are used in injection. The test measures the melt flow properties of resins in g10 min at a particular shear stress related to applied load and temperature. Fundamentals of melt flow testing linkedin slideshare. Melt flow indexer machines and instruments to test and.
Mfi 10 melt flow indexing machine large mwd corresponds with a greater shear sensitivity, i. The test protocol above is used for defining all of the equipment used during the test ie. Melt flow indexer qualifi 6000 series astm d1238, iso 13. Method a is a very simple and is focused on cutting the flowing extrudate with respect to time and recording the mass in order to. Normally, the test conditions for measurement of melt flow rate are specified in the material standard with a reference to this part of iso 13. One of the limitations of the melt flow rate method is in the testing of materials that are unstable at their test temperature. Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. Different standardised conditions of extrusion temperatures and pres. The protocol is followed in general except for the specific instructions presented in steps b f of this procedure. Melt flow rate depends on molecular weight, additives, and other ingredients. Standard test procedure and conditions to perform mfi.
More than just a quality control rheological parameter. The sample should be extruding at a rate such that the lower. The value obtained through the melt flow index test is a single data point. The melt flow index value allows for direct comparison of materials to each other and is a valuable tool for quality assurance. Note 1roundrobin testing indicates this test method may be suit. There are correlation charts if anyone wants to get viscosity in mpa or centipoises from a melt index number, but hardly anyone use s them in industry. Flow temperature of pure polypropylene by using a base load. In the present work, a method has been proposed to estimate the rheograms of a melt at temperatures relevant to its processing conditions with the use of a master curve, knowing the melt flow index and glass transition temperature of the material. Standard test method for melt flow rates of thermoplastics by. Astm d1238 standard test method for melt flow rates. Melt flow index testing associated polymer labs, inc.
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