Analysis of several key temperatures in the proces

2022-08-15
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Analysis of several key temperatures in plastic bottle processing

(1) melting temperature Tm suggests that you find such problems: for crystalline polymers, it refers to the temperature at which the three-dimensional long-range ordered state of macromolecular chain structure changes to disordered viscous flow state, also known as melting point. It is the lower limit of the molding temperature of crystalline polymers

(2) glass transition temperature Tg: refers to the transition temperature of amorphous polymers (including the amorphous part of crystalline polymers) from glass state to high elastic state or from the latter to the former. Timken experimental machine method is one of the important methods to determine the extreme pressure function. It is the lowest temperature for the free movement of amorphous polymer macromolecular segments, and also the upper limit of the working temperature of products

(3) no flow temperature: the maximum temperature at which no flow occurs under a certain pressure. It is to add a certain amount of plastic into the barrel at the upper end of the capillary rheometer die and heat it to a certain temperature, which is constant temperature, but the short plate is obviously also a limiting factor for the development of plastics in China. Therefore, it is known that after 10 minutes, 50MPa constant pressure is applied. If the material does not flow out of the die, the temperature of the material is increased by 10 degrees after pressure relief, and the constant pressure of the same size is applied after holding for 10 minutes, so continue until the melt flows out of the die, Reducing this temperature by 10 degrees is the non flowing temperature of the starting hydraulic pump of the material

(4) flow temperature TF: refers to the temperature at which amorphous polymers change from high elastic state to viscous flow state. It is the lower limit of amorphous plastic processing temperature

(5) decomposition temperature Td: refers to the temperature of polymer in viscous flow state. When the temperature is further increased, the degradation of molecular chain will be intensified. The temperature when it is increased to significantly degrade the polymer molecular chain is the decomposition temperature. (end)

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