Browse Prior Art Database

PROCESS FOR PREPARING BLOCK COPOLYMERS

IP.com Disclosure Number: IPCOM000023274D
Original Publication Date: 1977-Apr-30
Included in the Prior Art Database: 2004-Mar-29
Document File: 2 page(s) / 313K

Publishing Venue

Xerox Disclosure Journal

Abstract

There is described a process for the preparation of block co-polymers having photoconductive segments derived from a vinyl monomer and segments derived from a second addition monomer (which may also be photoconductive). The vinyl monomer may be, for example, any of the vinylcarbazoles, vinylpyrene, vinylnaphthalene or the like. The second addition monomer may be, for example, an acrylate, diene, or certain vinyl polymers such as polystyrene. The process is especially suitable for the preparation of block copolymers where at least one of the constituent monomers is incapable of polymerization by anion initiated polymerization yet capable of radical initiated polymerization. Either monomer is polymerized in a manner so as .to introduce terminal peroxide groups onto the individual segments of the polymer. This may be achieved by terminating the polymerization of the polymer with a chemically reactive group which can be subsequently converted to a peroxide or by the free radical initiated polymerization of the monomer with a sequential free radical initiation compound having at least two distinct species of free radical generating groups, one being more stable than the other. The polymer having such terminal groups is then contacted with the other monomer and the terminal groups are decomposed so that the second monomer is polymerized and propagated as a polymer segment from the first polymer. Where the various monomers used differ sub-stantially in thermal stability, it is preferred to polymerize the less thermally stable monomer first. In addition where the monomers differ in relative purity, it is preferred to polymerize the more impure monomer first. Termination of polymerization of the first polymer segment or the copolymer may be either by disproportionation or coupling which will control the product obtained After having prepared block copolymers by this process, it is generally necessary to sep-arate any homopolymer fractions which may be present. This may be done by simple solvent extraction techniques.

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XEROX DISCLOSURE JOURNAL

PROCESS FOR PREPARING BLOCK Proposed Classification
COPOLYMERS U.S. Cl. 260/885
Milan Stolka mt. Cl. C081 31/02

There is described a process for the preparation of block co-
polymers having photoconductive segments derived from a vinyl
monomer and segments derived from a second addition monomer
(which may also be photoconductive). The vinyl monomer may
be, for example, any of the vinylcarbazoles, vinylpyrene,
vinylnaphthalene or the like. The second addition monomer may
be, for example, an acrylate, diene, or certain vinyl polymers
such as polystyrene. The process is especially suitable for
the preparation of block copolymers where at least one of the
constituent monomers is incapable of polymerization by anion
initiated polymerization yet capable of radical initiated
polymerization. Either monomer is polymerized in a manner so
as .to introduce terminal peroxide groups onto the individual
segments of the polymer. This may be achieved by terminating
the polymerization of the polymer with a chemically reactive
group which can be subsequently converted to a peroxide or by
the free radical initiated polymerization of the monomer with
a sequential free radical initiation compound having at least
two distinct species of free radical generating groups, one
being more stable than the other. The polymer having such
terminal groups is then contacted with the other monomer and
the terminal groups are decomposed so that the second monomer
is polymerized and propagated as a...