Branched and hyperbranched polyetherimides

Details Branched and hyperbranched polyetherimides Branched and hyperbranched polyetherimides

1999-11-05

2001-12-25

Dawson, Robert (Department: 1712)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

From silicon reactant having at least one...

C528S170000, C528S029000

Reexamination Certificate

active

06333390

ABSTRACT:

FIELD OF THE INVENTION
The invention involves branched and hyperbranched polyetherimides from stable A
1
B
n
(where n≧2), AB, AA, and BB monomers; A
m
end-capping agents (where m=1); B
n
cores (where n≧1) and combinations thereof; with controllable degrees of branching (DB=0-1), molecular architectures, end-group compositions, along with methods for their preparation. More specifically, the present invention relates to stable A
m
B
n
monomers (as shown generally in
FIG. 1A
, and more particularly in
FIG. 1B
) and methods for making them, as well as using those monomers in methods for producing stable polyetherimides (PEIs), including high molecular weight star PEIs (as shown in FIG.
2
A), linear PEIs (as shown in FIG.
2
B), hyperbranched PEIs (as shown
FIGS. 3A
,
3
B,
4
A,
4
B, and
4
C), and dendritic PEIs (as shown in FIGS.
5
A and
5
B). The stable PEIs of the present invention have advantageous and unique properties never attained by prior compounds. More specifically, the present invention provides compounds that have high solubility and low viscosity, and which are thermally and chemically stable. Thus, the stable compounds of the present invention can be used for many products a wide variety of applications, including but not limited to, coatings, electronic encapsulation, and injection molding processes. The present invention can be used for many products including but not limited to wire enamels, sterilizable medical equipment, computer chip products, and aircraft engine parts.
BACKGROUND OF THE INVENTION
Those of skill in the art to which this invention pertains will recognize the typical terminology used in the art. As a convenience for others whom may not be of skill in the art, the following description is provided so that they can better appreciate the limited nature of the prior art and advantages and importance of the present invention.
The term that describes or quantifies the branched nature of a polymer is called the degree of branching (“DB”).
FIG. 6A
is a schematic representation of terminal (T), linear (L), and dendritic (D) building blocks of AB
2
type polymers. Polymers having a degree of branching approaching 0 are said to be linear (e.g., as shown in
FIG. 6B
) and those having a degree of branching approaching 1 are said to be dendritic (e.g., as shown
FIG. 6D
) or “maximally” branched. Anything in between these two extremes is said to be branched or hyperbranched depending upon the degree of branching (e.g., as shown in FIG.
6
C). The formula that determines the degree of branching for the one-pot polymerization of an AB
2
type monomer is given below:
DB
=
2
⁡
[
D
AB
2
]
2
⁡
[
D
AB
2
]
+
[
L
AB
2
]
(
1
)
In equation 1 above, [D
AB2
] and [L
AB2
] represent mole fractions of dendritic and linear segments, that are incorporated into the polymeric backbone. See Holter D., Burgath A., Frey H.,
Acta Polymer
48, 30-35 (1997). The equation that determines the degree of branching for the one-pot polymerization of an AB/AB
2
type polymerizations is given below:
DB
Frey
=
2
⁡
[
D
AB
2
]
2
⁡
[
D
AB
2
]
+
{
L
AB
2
]
+
[
L
AB
]
(
2
)
In equation 2, [D
AB2
], [L
AB2
] and [L
AB
] represent mole fractions of dendritic and linear segments (FIG.
6
E), respectively. See Frey, H.; Hölter, D.,
Acta Polymerica
1999, 50(2-3), 67-76.
The physical properties of the polymers are determined by the size, shape, and peripheral chemistry (endgroups/B groups) of the polymer. The physical properties (e.g., crystallinity, solution viscosity and solubility) of dendritic macromolecules have been shown to be drastically different from their linear counterparts. See Hawker C. J.; Malmstrom E. E.; Frank C. W., Kampf J. P.,
Journal of the American Chemical Society
, 1997, 119, 9903-9904; and Frechet J.; Hawker C. J.; Gitson I.; Leon J. W.,
Journal of Material Science
-Pure Applied Chemistry 1996 A33(10), 1399-1425. The reason for this is believed to be that dendrimers are discrete molecules whose physical properties are determined by their unique globular shape (lack of intermolecular interactions) and the number of endgroups that occupy their periphery. This is in direct contrast to linear polymers whose physical properties are determined by chain entanglements (intermolecular interactions) and the structure of the repeat unit.
Linear Polymers in General
The majority of products in the plastics industry consist of linear polymers. This linear nature affords diverse physical and mechanical properties. The physical properties of linear polymers are highly dependent on molecular weight. Two examples of such properties are solubility and viscosity. As the molecular weight increases, the viscosity of the material increases. This can be a beneficial property if a viscous material is desired, but in many industrial processes, e.g., where injection molding is the processing method of choice, extremely viscous materials slow down the process and viscosity can become a limiting step of production. Also, as the molecular weight increases, the solubility decreases. If solubility resistance is the desired trait, then this is a suitable outcome. However, in other applications, e.g., the manufacture of coatings or films from liquids, low solubility leads to difficult manufacturing problems.
Thus, there is a need for materials that have much lower viscosity and much higher solubility than linear compounds, yet still retain the advantageous properties of linear compounds. These properties would make such materials ideal commercial candidates for use as additives or property modifiers for commercial coatings and injection molding processes, and thus useful in large volume industrial applications.
Dendritic Polymers in General
Dendrimers are “perfect,” or maximally branched macromolecules that have drawn considerable attention in the last few years. See Frechet J.; Hawker C. J.; Gitson I.; Leon J. W.,
Journal of Material Science
-Pure Applied Chemistry 1996 A33(10), 1399-1425; and Kim Y. H.,
Journal of Polymer Science
1998, 36, 1685-1689. From a materials standpoint, dendrimers have extremely useful properties, such as increased solubility and reduced viscosity at high molecular weights. However, attempts to make dendrimers have resulted in materials whose synthesis is extremely expensive, time consuming, and labor intensive (e.g., extremely difficult to purify).
Hyperbranched Polymers in General
The synthesis of hyperbranched polymers is an area of research that was discussed as early as 1952. See Flory P. J.,
J. Am. Chem. Soc
. 1952, 74, 2718. More recently, interest in hyperbranched polymers has increased due to their possible use as alternatives to dendrimers. See Frechet J.; Hawker C. J.; Gitson I.; Leon J. W.,
Journal of Material Science
-Pure Applied Chemistry 1996, A33(10), 1399-1425; and Kim Y. H.,
Journal of Polymer Science
1998, 36, 1685-1689. Thus far however, attempts to synthesize monomers necessary to make hyperbranched polymers have been costly and difficult, leading to the limited production of monomeric starting materials. The lack of available monomeric starting materials has slowed the bulk property testing of the hyperbranched polymers that could make them viable candidates for commercial applications. Nonetheless, much effort has been given to solve this problem and researchers have been trying to develop new methods and materials that utilize the hyperbranched approach to make cost-efficient, scalable hyperbranched polymers that mimic dendrimers, as evidenced by Frechet J.; Hawker C. J.; Gitson I.; Leon J. W.;
Journal of Material Science
-Pure Applied Chemistry 1998, A33(10), 1399-1425; Kim Y. H.,
Journal of Polymer Science
1998, 36, 1685-1689; and the United States Government Report (NIST) entitled “Workshop on Properties and Applications of Dendritic Polymers: Speaker Abstracts: Literature Review on Characterization, Modeling, and Applications” (July 9-10, 1998).
Moreover, to the extent that scalable quantities of monomers have been made, many of the hyperbran

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