THE EFFECT OF EC ON ORIENTATION AND RELAXATION OF PP OBTAINED VIA DYNAMIC PACKING INJECTION MOLDING

Yong Wang; Bing Na; Qiang Fu

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THE EFFECT OF EC ON ORIENTATION AND RELAXATION OF PP OBTAINED VIA DYNAMIC PACKING INJECTION MOLDING

Papers | Updated：2021-06-21

- THE EFFECT OF EC ON ORIENTATION AND RELAXATION OF PP OBTAINED VIA DYNAMIC PACKING INJECTION MOLDING
- Vol. 23, Issue 1, Pages: 103-111(2005)
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- Published：20 January 2005
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Yong Wang, Bing Na, Qiang Fu. THE EFFECT OF EC ON ORIENTATION AND RELAXATION OF PP OBTAINED VIA DYNAMIC PACKING INJECTION MOLDING[J]. 2005, 23(1): 103-111.
DOI：

Yong Wang, Bing Na, Qiang Fu. THE EFFECT OF EC ON ORIENTATION AND RELAXATION OF PP OBTAINED VIA DYNAMIC PACKING INJECTION MOLDING[J]. 2005, 23(1): 103-111. DOI：

摘要

As a long term project aiming at engineering plastics based on polypropylene (PP)

in this work

we report the effect of ethylene-cellulose (EC) on the orientation and relaxation of PP obtained via dynamic packing injection molding (DPIM). 2d-WAXD results showed that PP with a highly oriented structure and a shish-kebab structure were achieved by DIPM

leading to an increase of tensile strength from 35.0 MPa to 48.6 MPa. The degree of orientation of PP was increased by adding only 1% of EC

resulting in a further increase of tensile strength from 48.6 MPa to 53.8 MPa. Shish-kebab was found to exist not only in the oriented layer but also in the core of the sample after adding EC

as evidenced by DSC result. This was understood as due to the overall decrease of viscosity by the addition of EC

thus an increasing of shear rate. Higher shear rate can favor the orientation of molecules and continuous growth of shish-kebab structure

resulting in a change of shish-kebab distribution along the sample thickness. On the other hand

the relaxation mode of shish-kebab in the melt re-crystallization of PP is also greatly affected by the presence of EC. A retarded relaxation of PP macromolecules was seen. Even more

SEM results showed that EC could form the short fibers in PP matrix along the shear flow direction. Compared with the morphology obtained by conventional injection molding

a much better dispersion and easy break-up of EC in PP matrix were observed for samples obtained by dynamic packing injection molding.

Abstract