Plastic bags have certain temperature characteristics
1 Flow temperature: refers to the temperature at which the amorphous polymer changes from a highly elastic state to a viscous flow state, which is the lower limit of the processing temperature of the amorphous plastic. The transition zone between the high elastic state and the viscous flow state of the polymer is called a viscous flow transition zone, and the corresponding transition temperature is called the flow temperature Tf. The flow temperature Tf is one of the main basis for determining the parameters of the polymer melt forming process.
2 the melting temperature: melting temperature refers to the temperature of the object from solid to liquid, usually expressed in Tm. For a crystalline polymer, the temperature at which a three-dimensional remote ordered state of a macromolecular chain structure is transformed into a disordered viscous state, also called a melting point. Is the lower limit of the processing temperature of crystalline polymer molding
3 Glass transition temperature: refers to the amorphous polymer including the amorphous portion of the crystalline polymer, the transition state from the glassy state to the high elastic state or the former. It is the lowest temperature for the free movement of the macromolecular segment of the amorphous polymer and the upper limit of the working temperature of the product. Above this temperature, the polymer exhibits elasticity; below this temperature, the polymer exhibits brittleness.
4 Decomposition temperature: refers to the polymer in a viscous flow state, when the temperature is further increased, the degradation of the molecular chain is intensified, and the temperature at which the polymer molecular chain is significantly degraded is the decomposition temperature.
In addition, there is a non-flowing temperature, which is the highest temperature at which no flow occurs under a certain pressure, and is a physical quantity corresponding to Tf.
