Polymer Bulletin 22, 21-24 (1989) Polymer Bulletin 9 Springer-Verlag 1989 Synthesis of diacetylenic-butadiene-acrylic acid block copolymers M. Strumia, H. Bertorello, and G. Lescano Departamento Quimica Org~nica, Facultad de Ciencias Quimicas, Universidad Nacional de C6rdoba, 5016 Cordoba, Argentina SYNOPSIS This paper describes the synthesis and post-polymerization in solution of a copolymer 1,3-butadiene-acrylic acid modified with diacetylenic pendant groups. The products were characterized by UV, IR and NMR spectros- copy. INTRODUCTION Novel structures often provide opportunities for new applications. Diacetylenic polymers are excellent for these type of studies. Several publications1,2,3 inform us about the polymerization of diacetylenes. In most cases, this polymerization occurs in the solid-state to transform an array of monomer molecular into a polymer chain whose backbone is best represented by the structure -(R)-CEC~ (1), where R is a substituent group. However, very few examples about the solution properties of diacetylenic polymers have been reported in the literature, probable due to their low solubility. 4,5,6 The work presented herein concerns the incorporation of a diacetylenic monomeric structure (1) into a butadiene-acrylic acid co-oligomer previously obtained by us.(1) was incorporated as pendant group along the polymer backbone. Polymerization of this modified oligomer led to soluble polymers showing different colors. Purification of the products together with solution and film studies were performed and are the subject of the present work. EXPERIMENTAL SECTION The resins containing diacetylenic groups were synthesized by using butadiene-acrylic acid co-oligomers as the starting material (Polymer 1). They were synthesized by bulk polymerization using 1,3-butadiene, acrylic acid and benzoyl peroxide as catalyst.7 They were purified by fractional precipitation using benzene solvent and ethanol non-solvent. Fractions F1, F 2 and FR were collected. The modified polymers were synthesized from FI, F 2 and F~. In oPder to introduce the diacety]enic groups into polymer l, the carboxyl groups were converted to chlorides using thionyl chloride (Fluka) in benzene at O~ In this way, polymer 2 was reacted with lO,12- docosadiyne-l,22-diol with a relation of l eq. -COOH:1.25eq. of I giving the polymer 3, 4 and 5. This reaction was performed at reflux in THF for