Crosslinking of new elastomers functionalized with carboxyl groups

Abstract

Crosslinking of new elastomers functionalized with carboxyl groups RAPID COMMUNICATION Summary-The new carboxylated acrylonitrile-butadiene (XNBR) and styrene-butadiene (XSBR) rubbers produced were crosslinked with zinc oxide. The cure products are characterized by acceptable stress-strain properties. The increase in ZnO amount used, after exceeding of stoichiometric quantity with respect to-COOH groups content, does not improve the stress-strain properties. The curing of new XNBR and XSBR with ZnO leads to the formation of ionic crosslinks. An increase in swelling degree in toluene after action of NH 3 vapors, capable to destroy the ionic bonds, confirms this conclusion. The best stress-strain properties of cured products were achieved when carboxylated rubbers were hybrid cured, e.g. using simultaneously zinc oxide and sulfur, in the presence of N-cyclohexyl-2-benzothiazolesulfenamide as vulcanization accelerator. The products of such crosslinking contain both ionic and sulfide bonds and are characterized by the tensile strength of 8 MPa in cured state.

Design of “Zn2+ Salt-Bondings” Cross-Linked Carboxylated Styrene Butadiene Rubber with Reprocessing and Recycling Ability via Rearrangements of Ionic Cross-Linkings

“…The ideal effective cross-linking in the XSBR composites was believed to be the formation of Zn 2+ salts: one ZnO reacted with two −COOH groups which belonged to separate XSBR molecules to create one Zn 2+ salt-bonding. 42,43 However, one important precondition for the formation of Zn 2+ salt-bondings was the effective contact between ZnO and separate −COOH groups, as illustrated in Figure 2b. More zinc oxide absolutely had higher chance to contact −COOH; however, the ideal effective contact might be reduced due to the shielding effect of mass zinc oxide, as shown in Figure 2c.…”

“…Simultaneously, the spontaneously aggregated ion clusters had high moduli which functioned as effective reinforcing agent . This enlightens us to coordinate carboxylated rubbers with metal oxides, − where the reactions of carboxylic groups and metal oxides generate massive salt-bondings to realize recycling ability for rubbers. Based on idea above, in this paper, we selected carboxylated styrene butadiene rubber (XSBR) to coordinate with zinc oxide (ZnO) to form an ionic cross-linked network.…”

The Use of Copper Oxides as Cross-Linking Substances for Chloroprene Rubber and Study of the Vulcanizates Properties. Part I

“…This rubber group includes chloroprene rubber [ 4 , 5 , 6 , 7 , 8 ], chlorosulfonated polyethylene [ 9 ] and halogenobutyl rubbers: chlorobutyl [ 10 , 11 , 12 ] and bromobutyl [ 12 , 13 ]. For cross-linking of these materials, a mixture of two oxides is used: zinc oxide [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ] and magnesium oxide [ 4 , 6 , 7 , 8 , 9 , 11 , 13 , 14 , 16 , 17 , 18 ]. Zinc oxide is a compound in the form of white hexagonal crystals.…”

“…Cross-linking of rubber containing halogen atoms occurs as a result of the reaction of this atom with zinc oxide, resulting in the formation of a Lewis acid (e.g., zinc chloride) [ 5 , 6 , 7 , 10 , 15 ]., whereas magnesium oxide is an acceptor of the formed hydrogen chloride [ 15 ]. Additionally, ZnO and MgO can be used for the cross-linking of carboxylated acrylonitrile-butadiene rubber [ 16 , 17 , 18 ].…”

Interelastomer reactions in unconventional elastomer blends

“…Do sieciowania elastomerów funkcjonalizowanych grupami jonotwórczymi stosowano tlenki, wodorotlenki oraz inne pochodne metali stwierdzaj¹c, ¿e stopieñ usieciowania elastomeru zale¿y zarówno od ilooeci, jak i od rodzaju wprowadzonego do uk³adu zwi¹zku metalu [12,13,[16][17][18]. Oczekiwalioemy zatem podobnego wp³ywu rodzaju zwi¹zku metalu na sieciowanie mieszanin CSM/XNBR.…”