Masters Theses

Changhong Yin

Date of Award

5-1996

Degree Type

Thesis

Degree Name

Master of Science

Major

Polymer Engineering

Major Professor

Joseph E. Spruiell

Committee Members

D. C. Bogue, E. S. Clark

Abstract

A study of the effects of pigment additions on the development of structure and properties of drawn yarn prepared from of isotactic polypropylene (PP) is presented. Two pigments, one inorganic and one organic, were selected to produce colored spun and drawn polypropylene filaments with black and blue colors, respectively. Wide angle x-ray diffraction (WAXS), differential scanning calorimetry (DSC), density, and birefringence were used in the analysis of structural characteristics for both pigmented and unpigmented PP drawn filaments. Uniaxial tensile tests were also carried out.

The influence of pigment additions on the way that drawing process conditions influence the development of fine structure, as well as the mechanical properties of pigmented PP filaments, were investigated. An extensive statistical analysis is also provided to enhance a quantitative understanding of the effect of pigment types, pigment concentration, draw ratio, draw temperature and draw speed on the final structure and properties of pigmented drawn PP filaments.

The results show that pigment additions have marked effects. on the PP drawn yarn mechanical properties. Under similar processing conditions the presence of pigments increases elongation, but lowers tenacity, yield strength and modulus. Compared with the inorganic pigment, Cabot 660 furnace black, the organic pigment, Phthalyl blue, has more impact on PP drawn yarn mechanical properties.

The drawability and drawn yarn mechanical properties are also greatly affected by the pigment concentration. Finally, changes of draw ratio and draw temperature may improve or damage fine structure of PP drawn filaments and therefore affect pigmented PP drawn properties. The structure and properties differences between the natural, unpigmented PP and pigmented PP are also discussed.

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