APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014;
Denver, Colorado
Session A14: Invited Session: Industrial Applications of Olefin Block Copolymers
8:00 AM–11:00 AM,
Monday, March 3, 2014
Room: 301-303
Sponsoring
Unit:
DPOLY
Chair: Brent Neal, Milliken and Company
Abstract ID: BAPS.2014.MAR.A14.3
Abstract: A14.00003 : The versatility in morphology and physical properties offered by chain shuttled olefin block copolymers
9:12 AM–9:48 AM
Preview Abstract
Abstract
Author:
Jeffrey Weinhold
(The Dow Chemical Company)
Chain shuttling catalysis enables the production of olefin block copolymers
(OBCs) with a wide range of block compositions. Unique morphology and
property combinations can be achieved with highly crystalline hard blocks
and low crystallinity or fully amorphous soft blocks. The effect of the
amount of comonomer in the soft blocks on phase behavior, morphology and
properties will be the focus of this presentation. In one class of
materials, the soft blocks contain just enough octene comonomer to give
elastic behavior but, unlike a random copolymer-based olefin elastomer, the
soft segments are held together by thick crystals formed by the hard blocks.
In addition to strengthening the network, these crystals provide temperature
resistance and, by solidifying at higher temperature, they allow faster
product fabrication. Increasing the soft block's octene content yields the
next class of materials which have improved compatibility with
polypropylene. This property allows the formation of fine,
uniformly-dispersed OBC elastomer particles in PP. Since the impact strength
of toughened PP increases as the particle size is reduced, a lower amount of
elastomer is required to achieve an application's target for toughness. The
direct benefit of lower elastomer loading is an increase in modulus, which
enables lightweighting in applications. With further increases in the soft
block's octene content, the incompatibility between the hard and soft blocks
becomes large enough to cause the OBCs to form ordered melt morphologies. In
the solid state, the alternating crystalline and amorphous regions have
surprisingly large domain spacings and, due to the difference in refractive
index between the domains, the periodicity results in a partial photonic
band gap for frequencies in the visible spectrum. Comparisons to the
morphology of monodisperse block copolymers and the predictions of theories
will be presented. Also, the results of an extension to strong segregation
theory will be shown, providing greater insight into the behavior of these
polydisperse block copolymers.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2014.MAR.A14.3