Weekly topic: 5 wealth points for those who answer correctly, 2 wealth points for those who participate； Question 175
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This post was last edited by ljtjbx on 2015-9-16 13:26. Short answers and discussions: What are the three mechanical states of polymers? What are their respective characteristics? Which processing methods are suitable for each? Answer: The glassy state, the high-elastic state, and the viscous flow state are known as the three mechanical states of polymers. 1. In the glassy state, polymers have high modulus and low deformation, so they are not suitable for molding processes that involve large deformations. Suitable for secondary processing. 2. High elasticity: it undergoes significant reversible deformation; the polymer has high viscosity and also possesses a certain degree of strength. Applicable to forming processes with large deformations. 3. Viscous flow state, with significant irreversible deformation and low melt viscosity. Applicable to molding processing techniques that require high liquidity. —————————————————— Please note: We will close this thread after 24 hours, and at that time we will announce the best reply (the best assistance), as well as the answer and explanation. Charisma Reward: Those who post a topic in this section within two days to provide a detailed explanation or discussion on the knowledge points related to this question are asked to reply/comment in this post to inform us, and we will have a moderator award them charisma points. It is not allowed to simply copy and paste; original content is preferred, with at least some organization by the user along with personal insights.
The glassy state, the high-elastic state, and the viscous flow state are known as the three mechanical states of polymers.
Incomplete: Q The glassy state, high-elastic state, and viscous flow state are known as the three mechanical states of polymers. Glassy state: Polymers have high modulus and low deformation, so they are not suitable for molding processes involving large deformations; they are appropriate for secondary processing. Elastomeric state: produces significant reversible deformation ； Polymers have high viscosity and a certain degree of strength. Suitable for: forming processes with large deformations. Visco-flow state: large irreversible deformation ； The melt viscosity is low. Usage: Molding processing technology with high liquidity requirements.
The three mechanical states of polymers are the glassy state, the high-elastic state, and the viscous flow state. Glassy state: In the glassy state below the glass transition temperature, the molecular motion of polymers is characterized by chain segments, side chains, and branches; as a result, the material is hard but highly brittle. Polymers have high modulus and low deformation, so they are not suitable for molding processes involving large deformations, but are appropriate for secondary processing. Elastomeric state: As the temperature rises and the material enters the elastomeric state, the moving units of the polymer become chain segments, granting the polymer excellent elasticity. It can undergo significant reversible deformation; the polymer has high viscosity and certain strength, making it suitable for molding processes that require large deformations. Viscous flow state: As the temperature rises further and the material enters the viscous flow state, all of the polymer molecules begin to move; the polymer flows but has high viscosity, and the unit of motion at this stage is the entire molecular chain. It exhibits significant irreversible deformation and low melt viscosity, making it suitable for molding processes that require high fluidity.
The three mechanical states of polymers – learn about it!
The three mechanical states are the glassy state, the high-elastic state, and the viscous flow state. The glassy state is the state of polymers below their glass transition temperature; in this state, their molecular chains cannot move freely, which makes the material hard but also quite brittle, such as in thermosetting plastics like epoxy resin. In polymers in the highly elastic state, the units of motion become chain segments. Such polymers possess excellent elasticity, such as rubber. Polymers in a viscous flow state have all of their chain segments capable of moving; such polymers are fluid but exhibit high viscosity, and this is generally the state encountered during the processing of thermoplastic plastics. Glassy plastics, such as epoxy resins, can be poured, and the resulting products can be machined using methods such as turning, milling, drilling, sawing, punching, and so on ； Rubber is generally used in its highly elastic state, and can be produced by calendering ； Polyurethane elastomers can also be produced by casting ； Ordinary plastics are processed in their viscous flow state, with common processing methods being injection molding and extrusion.
This post was last edited by zdl1966 on 2015-9-15 10:59. Three states: glassy state, high-elastic state, and viscous flow state. Glassy state: At low temperatures, segmental motion is frozen; only local movements such as those of side groups, chain links, and chain length occur, resulting in minimal deformation. Suitable for machining such as turning and milling. High-elastic state: Segment movement is fully developed, resulting in large deformation that can be restored. Suitable for vacuum forming, pressure forming, calendering, and bending. Viscoplastic state: Intense movement of chain segments leads to relative displacement of these segments, resulting in irreversible deformation. Suitable for spinning, injection, extrusion, blow molding, etc
What are the three mechanical states of polymers? What are their respective characteristics? Which processing methods are suitable for each? The glassy state, the high-elastic state, and the viscous flow state are known as the three mechanical states of polymers. It is characterized by a high elastic modulus and high internal energy; the bond lengths in the polymer backbone are long, and the bond angles can only change slightly, making it impossible to achieve large-scale deformation during molding. It primarily involves cold working processes such as turning, filing, drilling, and threading. In the highly elastic state, the internal energy is reduced and the elastic modulus is lower; under external forces, the molecular chains move, resulting in an increased ability to deform, which allows for large-scale deformation processing such as rolling and thermoforming. Viscoplastic state: Under the action of external forces, the entire molecular chain can move, the material undergoes continuous deformation, and it can be extruded or injected
What are the three mechanical states of polymers? What are their respective characteristics? Which processing methods are suitable for each? The glassy state, the high-elastic state, and the viscous flow state are known as the three mechanical states of polymers. Polymers exhibit small deformations under external forces and display Hookean elastic behavior: the deformation occurs instantaneously, and once the external force is removed, the deformation is immediately restored. They are hard and brittle, and this mechanical state is similar to that of inorganic glass; it is referred to as the glassy state. Machining processes such as turning, milling, planing, and shaving: This type of stress can cause significant deformation, and the ability to return to its original state once the external force is removed is known as high elasticity; the corresponding mechanical state is referred to as the high-elasticity state. Processing methods such as vacuum forming, pressure forming, calendering, and bending involve the polymer turning into a viscous fluid, with its deformation being irreversible; this mechanical state is known as the viscous flow state. Processing methods such as melt spinning, injection, extrusion, blow molding, and lamination
The glassy state, the high-elastic state, and the viscous flow state are known as the three mechanical states of polymers. (1) Glassy state: The polymer has a high modulus and low deformation, so it is not suitable for molding processes that involve large deformations. Applicable: secondary processing. (2) Elastomeric state: Generates significant reversible deformation ； Polymers have high viscosity and a certain degree of strength. Applicable: Forming processes with large deformations. (3) Viscous flow state: large irreversible deformation ； The melt viscosity is low. Applicable: Molding processes with high liquidity requirements.
The three mechanical states of polymers are the glassy state, the high-elastic state, and the viscous flow state. Characteristics of the glassy state: high internal energy and high elastic modulus; only slight changes can occur in the bond lengths and bond angles of the polymer backbone, resulting in minimal deformation. It is not suitable for large-scale deformation processing, but is appropriate for cold working such as turning, drilling, filing, and threading. Characteristics of the high-elastic state: reduced internal energy and lower elastic modulus. Under external forces, the molecular backbone moves, resulting in increased deformability; the deformation can be partially restored, allowing for large-scale deformation processing. It is suitable for rolling, hollow forming, and thermoforming processes. Characteristics of viscous flow state: Under the action of an external force, the entire molecular chain can move, causing the material to deform continuously; this deformation is irreversible, and this state is suitable for extrusion and injection molding processes.