NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Phenyl-Terminated Polyolefins via Living Coordinative Chain Transfer Polymerization with ZnPh2 as a Chain Transfer Agent
Published
Author(s)
Mark Wallace, Aaron Burkey, Lawrence Sita
Abstract
ABSTRACT: Living coordinative chain transfer polymeriza-tion (LCCTP) of α-olefins, including propene, 1-hexene, 1-decene, and 4-methyl-1-pentene, using the CPAM Hf pre-in-itiator 1, the borate co-initiator B1, and excess equivalents of diphenylzinc (ZnPh2) as chain transfer agent, provides excellent yields of the corresponding phenyl-terminated polyolefins with tunable degree of polymerization (DPn) and very symmetric and narrow molecular weight distribu-tion (e.g. Ð ≤ 1.1). Reactive quenching of ZnPh2-mediated LCCTP with molecular iodine (I2) further provides the or-thogonally difunctionalized α-iodo, ω-phenyl polyolefins (x-PAO-Ph). Use of diethylzinc (ZnEt2) in place of ZnPh2 under otherwise identical conditions provides the corresponding ethyl-terminated polyolefin products (x-PAO-Et) with nearly the same DPn and Ð values. A mechanism is proposed for R' group transfer from ZnR'2 and polymeryl (P) group transfer from ZnP2 during LCCTP that involves nucleophilic attack on a coordinated olefin and avoids formation of a Hf-R' bonded intermediate. These results serve to advance LCCTP further for the production of next generation poly-olefins.
Wallace, M.
, Burkey, A.
and Sita, L.
(2021),
Phenyl-Terminated Polyolefins via Living Coordinative Chain Transfer Polymerization with ZnPh2 as a Chain Transfer Agent, ACS Catalysis, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932342
(Accessed October 7, 2025)