聚合物注塑成型充模阶段流动取向分子机理研究

doi:10.11896/j.issn.1005-023X.2018.02.033

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Abstract

Taking the polycarbonate (PC) as research objective, the migration properties and morphological evolution of polymer chains under three dimensional periodic boundary condition were studied based on molecular dynamics (MD) simulation. And the flow induced orientation mechanism of polymer was revealed by comparing simulated and experimental results. The mean square displacement indicated that the orientation process was actually an coordinated conformation of polymer conglomeration, although the mean square displacement increased largely and the non-bond energy decreased rapidly while the shear rate increasing, the structure of polymer chains did not changed at all. At the same time, the randomly entangled polymer chains not only arranged along flow direction, but also separated from each other and tended to be dispersive distribution. The experimental results showed that birefringence increased with the increase of the injection rate and decreased along the flow direction, while the tensile properties in the orientation direction also increased with the increase of the degree of orientation, which is well consistent with the migration behavior and morphology evolution rules indicated by the simulation results.

Key words： injection molding polycarbonate molecular chain orientation molecular dynamics (MD)

Published: 25 January 2018

CLC number:

TQ320

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	Articles by authors
	Xuan YU
	Yong XIN

Cite this article:

Xuan YU,Yong XIN. Exploration on Orientation Mechanism of Polymer During Flow Stage in Injection Molding[J]. Materials Reports, 2018, 32(2): 327-332.

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http://www.mater-rep.com/EN/10.11896/j.issn.1005-023X.2018.02.033 OR http://www.mater-rep.com/EN/Y2018/V32/I2/327

(a)The monomer and (b)molecular chains model of PC

Shear rate of different PC model

(a)MSD and (b)the max MSD curve with different shear rates change of PC

(a)Diffusion coefficient and (b)viscosity of PC at different shear rates

(a)Bond length and (b)dihedral angle of PC during shearing flow

(a)Bond energy and (b)non-bond energy curves of PC in the shear field

Radius of gyration distribution of PC at different shear rates

The size of injection molds(mm)

(a)Birefraction and (b)tensile mechanical properties with different injection speed

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