Title page for ETD etd-06142001-134722


Type of Document Master's Thesis
Author Kumar, Amit
Author's Email Address akumar@vt.edu
URN etd-06142001-134722
Title Morphology, Crystallization and Melting Behavior of Statistical Copolymers of Propylene with Ethylene, 1-Butene, 1-Hexene and 1-Octene
Degree Master of Science
Department Materials Science and Engineering
Advisory Committee
Advisor Name Title
Marand, Hervé L. Committee Chair
Kander, Ronald G. Committee Member
Reynolds, William T. Jr. Committee Member
Keywords
  • alpha and gamma-phase
  • multiple melting
  • cross-hatching
Date of Defense 2001-06-12
Availability unrestricted
Abstract
In this thesis, the morphology, crystallization and melting behavior of polypropylene copolymers (propylene/ethylene, propylene/1-butene, propylene/1-hexene and propylene/1-octene) has been examined. The multiple melting behavior has been correlated with the presence of alpha and gamma phases and with the occurrence of cross-hatching morphology. The Crystallization and melting behavior of propylene/ethylene and propylne/1-butene are qualitatively similar and compatible with the expectations that the ethylene and butene comonomers are partly included in the propylene lattice. Propylene/1-hexene and propylene/1-octene copolymers exhibit remarkably similar behavior and morphologies consistent with the expectations that the hexene and the octene comonomers are rigorously excluded from the crystal lattice.

The origin and the crystallization time dependence of the multiple melting behavior is very different for these two pairs of copolymers. For PE and PB it is consistent with the melting of parent a-phase lamellae and alpha or gamma-phase daughter lamellae. For PH and PO copolymers it is very similar to that observed for ethylene-octene(EO) and ethylene-styrene(ES) copolymers and compatible with the melting of primary lamellae and secondary mosaic or fringed micellar structures.

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