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MFI Measuring device. The Melt Flow Index (MFI) is a measure of the ease of flow of the melt of a thermoplastic polymer.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.
In polymers, such as plastics, thermal degradation refers to a type of polymer degradation where damaging chemical changes take place at elevated temperatures, without the simultaneous involvement of other compounds such as oxygen. [1] [2] Simply put, even in the absence of air, polymers will begin to degrade if heated high enough. It is ...
Vicat softening temperature or Vicat hardness is the determination of the softening point for materials that have no definite melting point, such as plastics. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 mm 2 circular or square cross-section.
Typically, polymeric materials are characterized as elastomers, plastics, or rigid polymers depending on their mechanical properties. [ 5 ] The tensile strength , yield strength , and Young's modulus are measures of strength and elasticity, and are of particular interest for describing the stress-strain properties of polymeric materials.
Thermogravimetric analysis or thermal gravimetric analysis (TGA) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes. . This measurement provides information about physical phenomena, such as phase transitions, absorption, adsorption and desorption; as well as chemical phenomena including chemisorptions, thermal decomposition, and ...
Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition.Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment and recycling. [1]
One consequence of yielding is that as plastic deformation proceeds, an increase in stress is required to produce additional strain. This phenomenon is known as Strain/Work hardening. [18] For a viscoplastic material the hardening curves are not significantly different from those of rate-independent plastic material.
The Relative thermal index (RTI) is a characteristic parameter related to the ability of plastic materials to resist thermal degradation.. The RTI is part of the longterm thermal aging program (LTTA) described in the UL 746B standard from UL.