Zastosowanie generowanych in situ kwasow Lewisa do sieciowania elastomerow

Abstract

New unconventional method of crosslinking of styrene-butadiene rubber (SBR) and epoxidized natural rubber (ENR) was elaborated. To initiate the crosslinking process, Lewis acids generated in situ in reaction of acid precursors - chlorosulfonated polyethylene (CSM), differing in chlorine content (CSM - Table 1), and ZnO were used. The following properties of SBR/CSM/ZnO blends were determined: vulcametric moment (M), equilibrium swelling (Q v ) as well as the content of a fraction soluble in chosen solvents [2-butanone - MEK (Q v MEK), toluene - TOL (Q v TOL), or tetrahydrofurane - THF (Q v THF)], the content of chlorine bounded in the blends investigated (Table 6), Mooney- Rivlin elasticity constants (2C 1 N) as well as tensile strength (TS b ) (Table 2-4, 7). The effects of the type and amount of CSM (Figs. 2, 3) and ZnO (Fig.1) as well as SBR/CSM ratio on SBR curing rate and degree were investigated. For comparison, ZnO in SBR/CSM blend was substituted with another oxides: MnO 2 , CuO, SnO or Fe 2 O 3 (Fig. 8, Table 7). Only in the cases of SnO or Fe 2 O 3 acceptable while significantly worse results were obtained. Effect of ZnO content on ENR/CSM blend curing rate and degree has been also determined (Fig 9). Courses of SBR and ENR curing were analyzed using FTIR spectroscopy (Fig. 4 and 10, Table 5), dynamic thermomechanical analysis (DMTA - Fig. 6) and SEM (Fig. 7). SBR curing is a result of its phenyl rings' alkylation with polymeric halide (CSM) and autoalkylation with SBR chains containing 1,2- and 1,4-cis-butadiene monomer units, catalyzed with ZnCl 2 formed in situ from ZnO and CSM. IR spectra analysis leads to the conclusion that ENR curing is a result of oxirane groups' polymerization also catalyzed with in situ formed ZnCl 2 .