Structure and Property of Polybutylene, Polypropylene and Polyvinylidene Fluoride Crystallized From the Glassy State and Structure-Property - Processing Relationships of Polypropylene - Polybutylene Blends
Hsu, Chih-Chung
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/71809
Description
Title
Structure and Property of Polybutylene, Polypropylene and Polyvinylidene Fluoride Crystallized From the Glassy State and Structure-Property - Processing Relationships of Polypropylene - Polybutylene Blends
Author(s)
Hsu, Chih-Chung
Issue Date
1984
Department of Study
Metallurgy and Mining Engineering
Discipline
Metallurgical Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Polymer
Abstract
Ultraquenching was used to obtain glassy polybutylene (PB), polypropylene (PP) and polyvinylidene fluoride (PVF(,2)). The structure and properties of the as-quenched and subsequently crystallized samples were characterized by various techniques. The glass has no structure larger than 30 (ANGSTROM). PB crystallizes from the glass into tetragonal structure (II) at ca. 0(DEGREES)C, depending on the sample thickness, then transforms to twinned hexagonal structure (I) upon aging at room temperature. In the presence of isopentane, PB crystallizes partially from the glass into untwinned hexagonal (I') structure at ca. -100(DEGREES)C, the rest of the sample transforms to tetragonal structure at ca. 0(DEGREES)C. The exact temperatures of both transformations depend on the amount of isopentane present and sample thickness. Upon aging at room temperature the tetragonal structure converts to twinned hexagonal structure even faster than in the absence of isopentane. Dynamic mechanical spectra show the presence of two relaxation-like peaks at -27(DEGREES)C and -15(DEGREES)C for the ultraquenched samples, presumably T(,g)(L) and T(,g)(U) respectively. X-ray diffraction, DSC and torsion pendulum show PB crystallizes from the glass at T(,g)(U).
PP crystallizes from the glass into a nodular, smectic structure (80 - 100 (ANGSTROM) diameter) at ca. -20(DEGREES)C and then transforms to monoclinic microcrystals at ca. 40(DEGREES)C. Annealing above T(alpha) results in the formation of short fibers. Dynamic mechanical spectra also suggest the presence of two T(,g)s for the as ultraquenched samples, T(,g)(L) = -10(DEGREES)C and T(,g)(U) = 10(DEGREES)C. Crystalization from the glass occurs at T(,g)(L).
For PVF(,2), electron diffraction indicates crystallization from the glass at ca. -35(DEGREES)C into the form. Dynamic mechanical spectra indicate the existence of two T(,g)s for both air quenched and ultraquenched samples. For the air quenched samples T(,g)(L) = -40(DEGREES)C and T(,g)(U) = 30(DEGREES)C; for the ultraquenched samples T(,g)(L) = -38(DEGREES)C and T(,g)(U) is between 0(DEGREES)C and 55(DEGREES)C. Rapid crystallization from the glass results in the development of a nodular, microcrystalline morphology which can only be changed by annealing above T.
Blends of PP and PB were prepared by either melt mixing or solution mixing followed by ultraquenching. The crystallization behavior of the blends from the melt and glass, and the resulting morphology and physical properties were characterized by different methods. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
