The role of mold temperature in changing molecular chain morphology of flowing melt

Abstract

In order to gain a deeper understanding of the role of the mold temperature to the high-temperature melt during flow, molecular dynamics simulation is used to simulate the coarse-grained entangled molecular chains flow through the different mold temperatures. The transient function based on the movement factor is established to describe the change of the transition layer molecular chain with the different mold temperatures. The changed of the transition layer molecular chain decreases with the decrease of mold temperature. When the mold temperature is high, the molecular chains undergo a process of tilting U, tilting V, tilting W and even tilting folding morphology. When the mold temperature is low, mainly the tilting U morphology occurs, other morphology emerges is less. The stretch of molecular chain morphology transforms the arrangement, resulting in the density of core layer reaches 0.76–0.84 g/cm3, while the density of the shear layer is about 1.15–1.58 g/cm3. In order to establish the relationship between molecular chain morphology and mechanical properties, a quantity analogous to bending energy is used for characterization. As the mold temperature decreases, it reduces in the transition layer. From the viewpoint of molecular chain morphology and rigid-amorphous fraction, changes in molecular chain morphology increase the possibility of rigid-amorphous fractions, which increases the strength and rigidity of the shear layer.