| Abstract: | The viscoelasticity and stress‐softening behavior of chloroprene rubber (CR) filled with multiwalled carbon nanotubes (MWCNT) and carboxylated multiwalled carbon nanotubes (MWCNT‐COOH) were studied using a Rubber Process Analyzer 2000 (RPA2000). In the strain sweep measurements, it is found that CR/MWCNT and CR/MWCNT‐COOH compounds have different behavior on storage modulus (G′). With increasing strain, G′ of CR/MWCNT (100/8) compound decreases at strain less than 2°, while G′ of CR/MWCNT‐COOH (100/8) compound stays at constant, indicating that MWCNT‐COOH has stronger filler–filler network and filler–rubber interactions as compared to MWCNT in CR matrix. CR/MWCNT (MWCNT‐COOH) vulcanizates have higher G′ but lower loss modulus (G″) than the corresponding uncured compounds. Repeated strain sweep scans were carried out to study the stress‐softening behavior of CR compounds. A stress‐softening effect of the filled CR compounds is observed and becomes more pronounced with increasing loading of MWCNT or MWCNT‐COOH. The correlation between the Payne effect and stress‐softening effect of CR/MWCNT (MWCNT‐COOH) vulcanizates is also studied. It is found that the difference of the storage moduli at 0.1° and 10° strain amplitudes and the difference of storage moduli of first and second strain sweeps at 0.1° strain amplitude show a positive linear correlation. POLYM. COMPOS., 35:2194–2202, 2014. © 2014 Society of Plastics Engineers |
