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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]
The 'approach' region further guides the melt into the final shape, and begins to correct for any non-uniform flow. Finally, the 'lip' forms the melt into the final desired cross section and compensates for any remaining flow asymmetry. After exiting the lip of the die, the polymer melt will undergo die swell before curing. Die swell is an ...
Sheet/film extrusion is used to extrude plastic sheets or films that are too thick to be blown. There are two types of dies used: T-shaped and coat hanger. The purpose of these dies is to reorient and guide the flow of polymer melt from a single round output from the extruder to a thin, flat planar flow.
BUSAN, South Korea (Reuters) -Countries negotiating a global treaty to curb plastic pollution failed to reach agreement on Monday with over 100 nations wanting to cap production while a handful of ...
The processor controls how much voltage is applied, and for how long, depending on the fitting in use. As current is applied to the resistive wire, the coils heat up and melt the inside of the fitting and the outside of the pipe wall which weld together producing a very strong homogeneous joint. The assembly is then left to cool for a specified ...
Ultrasonic welding is a method of joining thermoplastic components by heating and subsequent melting of surfaces in contact. [1] Mechanical vibration with frequency between 10 and 70 kHz and amplitude of 10 to 250 μm is applied to joining parts. After ultrasonic energy is turned off, the parts remain in contact under pressure for some time ...
Typical with friction welding applications, higher melting temperature materials will require more energy to melt, so they will require more welding time or higher RPMs. [3] Common additives and filler will often alter the weldability of polymers. These additions can make the weld process more difficult, or change the intended properties of the ...
Radio-frequency welding, also known as dielectric welding and high-frequency welding, is a plastic welding process that utilizes high-frequency electric fields to induce heating and melting of thermoplastic base materials. [1] The electric field is applied by a pair of electrodes after the parts being joined are clamped together.