Carboxylic Rubbers. I. Synthesis and Structures

Abstract

It is well known that the high strength of unfilled (pure gum) natural rubber and some synthetic rubber compounds can be explained by the homogeneity of the polymer chain which determines its ability to crystallize or to orient on stretching. The character of the vulcanization network as well as the structure of the main chain is of importance. This has been verified by the use of polyethylene polyamines and other chemical compounds as vulcanization accelerators for butadiene-styrene rubber (SKS-30A) to produce high strength (up to 200 kg/cm2) gum rubber compounds. In certain cases, only the structure of the vulcanization network obtained with carboxyl-containing rubber compounds can account for obtaining the same effects as are obtained with natural or other synthetic rubber compounds as a result of homogeneity of polymer chain. The first work done by us on carboxyl-containing (carboxylic) rubbers was done in 1954\2-1955. In this work it was shown that polymers of isoprene and of butadiene, copolymers of butadiene with styrene, butadiene with acrylonitrile, and others, which contain small quantities of methacrylic acid (1\2-2 mole %) in the chain, can be vulcanized with oxides of divalent metals to give pure gum and lightly filled compounds characterized by high strength and elasticity, good resistance to heat aging and good cut growth resistance.

Reinforcement of nitrile rubber by in situ formed zinc disorbate

“…New diffraction peak is observed at 6.8°, being close to that of ZDS, indicating the complete formation of ZDS. According to the report of Dolgoplosk et al [26], a basic salt is first formed by the reaction of SA and ZnO. Then, the neutral salt is formed when the SA is excess.…”

Synthesis and characterization of high molecular weight carboxylated polybutadiene

“…All polymers were used as received and information about the molecular weight and microstructures was also provided by the suppliers. Catalyst PdCl 2 (PPh 3 ) 2 2 A solution of PdCl 2 (0.085 mol) in 750 mL distilled water and 2.5 mL concentrated HCl was added slowly into a warm (ca. 60°C) solution of triphenylphosphine (0.172 mol) in 1.5 L ethanol.…”

“…For example, the reactivity ratios for the methacrylic acid-butadiene system are r 1 Ϸ 0.526 and r 2 Ϸ 0.201. 2 Consequently, the cPBD formed during the beginning stage of the copolymerization is rich in methacrylic acid units and the composition of cPBD changes with the extent of the conversion. Another disadvantage of cPBDs synthesized by a free-radical copolymerization is that some degree of gelation also exists in the system.…”

“…1 Usually, cPBDs are synthesized through free-radical copolymerization of the butadiene monomer with acrylic acid or substituted acrylic acid monomers. [2][3][4][5][6] However, polymers synthesized by this method showed uneven distribution of the acid monomers. 2 This is due to the differences in the monomers reactivity.…”

“…[2][3][4][5][6] However, polymers synthesized by this method showed uneven distribution of the acid monomers. 2 This is due to the differences in the monomers reactivity. For example, the reactivity ratios for the methacrylic acid-butadiene system are r 1 Ϸ 0.526 and r 2 Ϸ 0.201.…”