Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Patent
1992-01-30
1993-03-30
Schofer, Joseph L.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C08F 2240
Patent
active
051985152
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to curable biscitraconimide containing compositions, copolymers of biscitraconimides with olefinically unsaturated materials, a process for curing these copolymers, and to articles of manufacture comprising the biscitraconimide(co)polymers.
Biscitraconimides are known compounds and can be prepared by the methods disclosed in, "The Synthesis of Biscitraconimides and Polybiscitraconimides," Galanti, A. V. and Scola, D. A., Journ. of Poly. Sci.: Polymer Chemistry Edition, Vol. 19, pp. 451-475, (1981), the disclosure of which is hereby incorporated by reference. These biscitraconimides are polymerized to tough amber-colored films that exhibit good thermal stability. In addition, the article points out that NMR analysis shows that the observed ratio of methyl protons at 2.1 ppm. to the methylene protons at 1.6 ppm. in the biscitraconimides is lower than the theoretical ratios for the imide monomers. The difference is explained as being due to a small degree of polymerization that could occur when the acid is dehydrated thermally.
"The Synthesis of Bisitaconamic Acids and Isomeric Bisimide Monomers," Galanti, A. V. et al., Journ. Poly. Sci.: Polymer Chemistry Edition, Vol. 20, pp. 233-239 (1982) also discloses a method for the preparation of biscitraconimides in the form of an isomeric mixture of the citraconic and itaconic imides.
In "The Development of Tough Bismaleimide Resins," Stenzenberger, H. D., et al., 31st International SAMPE Symposium, Vol. 31, pp.920-932 (1986) it is disclosed that bismaleimides are prime candidates for carbon fiber reinforced composites because of their properties. However, the article also points out that these materials tend to be brittle. Thus, several attempts have been made to improve the fracture toughness of the bismaleimides. First, the bismaleimides have been cocured with reactive elastomers such as carboxy terminated acrylonitrile-butadiene rubbers. Also, the bismaleimide polymers have been modified with comonomers which copolymerize via a linear chain extension reaction and include both diene type copolymerization reactions and "ene"-type copolymerization reaction. Thirdly, the bismaleimides have been modified with thermoplastic materials. Finally, the bismaleimides have been cured in the presence of ionic curing catalysts such as imidazoles and tertiary amines including diazobicyclo-octane (DABCO). Among the alternatives for improving the fracture toughness of the bismaleimides was the incorporation of diallyl benzenes. As shown in table 3 it was found that these materials provided acceptable properties only up to 40 weight percent of the maleimide. Once more than 40 weight percent of the maleimide was employed, a significant decrease in the flexural strength and flexural modulus was observed.
In "Bismaleimide Resins the Properties and Processing of `Compimide` BMI Resins," Segal, C. L., et al., 17th Nat. SAMPE Conference 17pp. 147-160 (1985) formulated bismaleimides are modified with acrylonitrile-butadiene rubbers to produce an increased fracture toughness. However, it was concluded that the rubber is not compatible with the base resin and an additional, pre-reaction step was necessary to accomplish the modification.
Bismaleimide-styrene compositions are known from European Patent Application 0 108,461 published on May 16, 1984, and, "Molecular Structure and Properties of Bismaleimide Styrene Cross-linked Copolymers," Winter, et al., Proceedings of the 3rd Annual Int. Conf. on Crosslinked Polymers, Lucerne, Switzerland, pp, 291-303, (1989). Example II of the European Patent application also discloses a copolymer of styrene, acrylic acid, bismaleimide and biscitraconimide. However, this material contains a relatively large amount of the bismaleimide and acrylic acid and thus is quite different from the material in accordance with the present invention. Most importantly, the copolymer including a biscitraconimide disclosed in this patent application has a strain % of 0.9, which is significantly lower than compositions of
REFERENCES:
patent: 3380964 (1968-04-01), Grundschober et al.
patent: 4568733 (1986-04-01), Parker et al.
patent: 5013804 (1991-05-01), Kramer
"The synthesis of Biscitraconimides and Polybiscitraconimides" Galanti, A. V. and Scola. D. A., Journ. Polym. Sci. Polymer Chemistry Edition, vol. 19, pp. 451-475 (1981).
"The Synthesis of Biscitraconamic Acids and Isomeric Bisimide Monomers" Galanti, A. V. et al., Journ. Polym. Sci.: Polymer Chemistry Edition, vol. 20, pp. 233-239 (1982).
"The Development of Tough Bismaleimide Resins", Stenzenberger, H. A. et al., 31st Int. SAMPE Symposium, vol. 31, pp. 920-932 (1986).
"Bismaleimide Resins Their Properties and Processing of Compidine BMI resins", Segal, C. L., et al. 17th Nat. Sample Conference, pp. 147-160 (1985).
"Molecular Structure and Properties of Bismaleimide-Styrene Cross-Lined Copolymers", Winter et al., Proceedings of the 3rd Annual Int. Conf. on Cross-linked Polymers, Lucenne, CH, pp. 291-303 (1989).
Hope Peter
Talma Auke G.
van Swieten Andreas P.
Akzo N.V.
Mancini Ralph J.
Morris Louis A.
Schofer Joseph L.
Walker Alex H.
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