Authors:
W. Liu State University of New York at Stony Brook Chemistry Department Stony Brook NY 11794-3400 USA Stony Brook NY 11794-3400 USA

Search for other papers by W. Liu in
Current site
Google Scholar
PubMed
Close
,
S. Kim State University of New York at Stony Brook Chemistry Department Stony Brook NY 11794-3400 USA Stony Brook NY 11794-3400 USA

Search for other papers by S. Kim in
Current site
Google Scholar
PubMed
Close
,
J. Lopez State University of New York at Stony Brook Chemistry Department Stony Brook NY 11794-3400 USA Stony Brook NY 11794-3400 USA

Search for other papers by J. Lopez in
Current site
Google Scholar
PubMed
Close
,
B. Hsiao State University of New York at Stony Brook Chemistry Department Stony Brook NY 11794-3400 USA Stony Brook NY 11794-3400 USA

Search for other papers by B. Hsiao in
Current site
Google Scholar
PubMed
Close
,
M. Keating E. I. duPont de Nemours and Company Wilmington DE 19880-0323 USA Wilmington DE 19880-0323 USA

Search for other papers by M. Keating in
Current site
Google Scholar
PubMed
Close
,
I.-H. Lee E. I. duPont de Nemours and Company Wilmington DE 19880-0323 USA Wilmington DE 19880-0323 USA

Search for other papers by I.-H. Lee in
Current site
Google Scholar
PubMed
Close
,
B. Landes Dow Chemical Company Midland MI 48667 USA Midland MI 48667 USA

Search for other papers by B. Landes in
Current site
Google Scholar
PubMed
Close
, and
R. Stein University of Massachusetts Chemistry Department Amherst MA 01003 USA Amherst MA 01003 USA

Search for other papers by R. Stein in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract  

In this study, the stepwise isothermal crystallization or thermal fractionation of Ziegler—Natta and metallocene based polyethylenes (ZN-PE and m-PE) with two kinds of branch lengths (ethyl and hexyl) and branch compositions were studied using simultaneous synchrotron small-angle X-ray scattering (SAXS)/wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The crystal long period and the invariant were determined by SAXS, and the variations of crystal unit cell parameters and the degree of crystallinity were determined by WAXD. The arithmetic mean length (Ln), the weightedmean length (Lw) and the broadness index (Lw/Ln) of the studied polyethylenes were previously determined by DSC. Results from these studies were interpreted using the model of branch exclusion, which affects the ability of the chain-reentry into the crystal phase. Multiple SAXS peaks and step-change in crystallinity change (WAXD) were seen during heating, which corresponded well with the crystal thickness distribution induced by stepwise crystallization. The effects of the heterogeneity of the 1-olefin branch length and the distribution on the crystal long period and the invariant as well as the degree of crystallinity were discussed.

  • Collapse
  • Expand

To see the editorial board, please visit the website of Springer Nature.

Manuscript Submission: HERE

For subscription options, please visit the website of Springer Nature.

Journal of Thermal Analysis and Calorimetry
Language English
Size A4
Year of
Foundation
1969
Volumes
per Year
1
Issues
per Year
24
Founder Akadémiai Kiadó
Founder's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
Publisher Akadémiai Kiadó
Springer Nature Switzerland AG
Publisher's
Address
H-1117 Budapest, Hungary 1516 Budapest, PO Box 245.
CH-6330 Cham, Switzerland Gewerbestrasse 11.
Responsible
Publisher
Chief Executive Officer, Akadémiai Kiadó
ISSN 1388-6150 (Print)
ISSN 1588-2926 (Online)

Monthly Content Usage

Abstract Views Full Text Views PDF Downloads
Dec 2023 14 0 0
Jan 2024 28 0 0
Feb 2024 25 1 0
Mar 2024 4 0 0
Apr 2024 14 0 0
May 2024 7 0 0
Jun 2024 2 0 0