Weekly topic: 5 wealth points for those who answer correctly, 2 wealth points for participation； Question 106
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Fill-in-the-blank: The factors that affect the fluid elasticity of polymers can be basically divided into two categories: ( ), ( ). The first are the molecular parameters of the polymer, and the second are the processing conditions.
Molecular parameters of polymers, processing conditions.
The first are the molecular parameters of ultra-high molecular weight polyethylene polymers; the second are the processing conditions.
Temperature and pressure, two factors.
The first is the molecular parameters of polymers, which include relative molecular mass, relative molecular mass distribution, the degree of chain branching, and the stiffness or flexibility of the chains. As the relative molecular weight increases, the normal stress of the polymer solution and melt increases, and the elastic effect becomes significant. As the relative molecular mass distribution widens, the fluid compliance increases, and elastic effects become significant ； Furthermore, the elastic effect of LDPE melts with long-chain branches is more pronounced. The second is the processing conditions. Processing conditions include thermodynamic parameters (mainly temperature and stock composition), kinematic parameters, and geometric conditions of flow, etc. Raising the temperature facilitates the relaxation process, thereby reducing the amount of elastic energy stored in the polymer fluid at the exit of the spinneret and thus minimizing the degree of elasticity. As the concentration increases, the polymer solution exhibits significant non-Newtonian behavior and normal stress effects; the higher the concentration, the more pronounced the elasticity of the solution. The higher the shear rate, the greater the swelling ratio, indicating that the elastic energy stored in the fluid is higher and the elastic effect is more pronounced.
First are the molecular parameters of ultra-high molecular weight polyethylene polymers； The second is the processing conditions. Molecular parameters include average molecular weight, molecular weight distribution, degree of long-chain branching, chain rigidity, etc. Processing conditions include thermodynamic parameters, kinematic parameters, and geometric conditions of flow, etc.
The factors affecting the fluid elasticity of polymers can be basically divided into two categories: (1) the molecular parameters of ultra-high molecular weight polyethylene polymers; (2) processing conditions
Molecular parameters of polymers, processing conditions
The factors affecting the fluid elasticity of polymers can be basically divided into two categories: (molecular parameters of the polymer) and (processing conditions).
The factors affecting the fluid elasticity of polymers can be basically divided into two categories: (1) molecular parameters of the polymer, and (2) processing conditions.
The factors affecting the fluid elasticity of polymers can be basically divided into two categories: (molecular parameters of the polymer) and (processing conditions).