Acta Chimica 52. (1967)

1. szám - Nyitray K.–Hardy Gyula: The radical copolymerization of norbornene derivatives with maleic anhydride

Acta Chimica Academiae Scientiarum Ilungaricae Tomus 52 (1), pp. 99—104 (1967) THE RADICAL COPOLYMERIZATION OF NORBORNENE DERIVATIVES WITH MALEIC ANHYDRIDE K. NyITRAY and Gy. HARDY (Research Institute for Plastics, Budapest) Received May 17, 1966 A study of the radical polymerization kinetics of norbornene derivatives [1] has shown that the radical polymerization of norbornene-carboxylic acid and nitrile can be described by the relations deduced for dead-end polymerization. It was believed for a long time that maleic anhydride in itself was in­capable of polymerization, but lately Joshi [2] has demostrated the homopoly­merization of this anhydride in the presence of higher concentrations of benzoyl peroxide; the kinetics of this polymerization also resembled that of the dead­end processes. The opinion about the incapability of maleic anhydride to homopolyme­rization (self-addition) had probably been based on the relatively low reactivity of this substance in comparison with vinyl compounds. Therefore, interesting new information may be expected from a study of the copolymerization processes of monomers whose reactivity is equal to or even lower than that of maleic anhydride. Little has been published so far on the copolymerization reactions of norbornene derivatives. A U. S. patent [3] describes the benzoyl peroxide­­initiated copolymerization of norbornene and maleic anhydride. Judge and Price [4] have studied the copolymerization of methyl norbornene-carboxylate with vinylidene carbonate, while Imoto, Otsu and Ito [5] reported the copoly­merization of norbornene-nitrile with styrene, vinyl acetate and vinyl chloride. Experimental The synthesis and properties of 5-carboxy-bicyclo [2.2.1 ]-heptene-(2) (norbornene­­carboxylic acid), methyl bicyclo [2.2.1 ]-hept-2-ene-5-carboxylate (norbornene-carboxylic methyl ester) and of 5-cyano-bicyclo [2.2.1]-heptene-(2) (norbornene-nitrile) used in the experi­ments have been described in an earlier paper [1]. Maleic anhydride, analytical grade (Reanal), was used. The reaction mixtures were treated in three cycles of freezing, evacuation, and melt­ing to remove, and the glass ampoules were sealed under vacuum. The initiator was 2% (w/w) of benzoyl peroxide, and copolymerization was carried out at 70° for three hours. The systems containing norbornene-carboxylic acid, or methyl norbornene-carboxylate were then dissolved in acetone, and the copolymer precipitated with ether; the norbornene­­nitrile copolymer was precipitated from the acetone solution with methanol. Under such conditions, maleic anhydride does not give a homopolymer and homopolymers of the norbor­nene derivatives are soluble in the precipitating agent; therefore, the presence of a precipitate conclusively proves the formation of a copolymer. Acta Chimica Academiae Scientiarum Hungaricae 52, 1967

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