With the growing volume of waste rubber products, the pressures on the environment and resources become increasingly serious. The reclamation of waste rubber products is one of the practical methods to meet this challenge. Therefore, the application of reclaimed rubber (RR) attracts researchers' attention. In this work, different contents of natural rubber (NR) matrix are replaced by RR and the reinforcing behavior of the RR phase is discussed. The results show that the crosslinking density, Payne effect and 100% modulus increase with increase in RR content in the NR/RR blends when the RR content is not more than 60 phr, and then drop when the RR content gets to 80 phr. It is inferred that both the NR and the RR constitute co-continuous phases when the RR content is 60 phr, and the RR phase is the only continuous phase when its content reaches 80 phr, which can be confirmed by SEM observation. Besides, the curing rate is enhanced with increase of the RR content. It is also found that structures with high crosslinking density appear when the RR is incorporated into the NR matrix. Finally, it is proposed that carbon black in the RR, a structure with high crosslinking density and a continuous rubber matrix are important factors influencing the reinforcement behaviour in RR filled rubber composites.

To meet the comprehensive demand for flexible microwave absorbing (MA) materials, a novel MA rubber containing homemade Polypyrrole nanotube (PPyNT) is produced based on the natural rubber (NR) and acrylonitrile-butadiene rubber (NBR) blends. To achieve the optimal MA performance in the X band, the PPyNT content and NR/NBR blend ratio are adjusted in detail. The 6 phr PPyNT filled NR/NBR (90/10) composite has the superior MA performance with the minimum reflection loss value of −56.67 dB and the corresponding effective bandwidth of 3.7 GHz at a thickness of 2.9 mm, which has the merits in virtue of achieving strong absorption and wide effective absorption band with low filler content and thickness compared to most reported microwave absorbing rubber materials over the same frequency. This work provides new insight into the development of flexible microwave-absorbing materials.

In this work, the Argon (Ar) plasma technology is adopted for pyrolytic carbon black (CBp) modification and the N330/Modified‐CBp (MCBp) hybrid is then incorporated into the Natural Rubber (NR) matrix. Compared with CBp, the MCBp has smaller particle size, lower ash content, higher specific surface area, and surface activity based on the results of laser diffraction method, transmission electron microscope (TEM), thermogravimetric analysis, gas sorption analysis (Nitrogen), acetone solvent, and X‐ray photoelectron spectroscopy. Among them, Dv (90) is found to have reduced by 20% while the specific surface area increased by 4%. According to the bound rubber content experiments, the equilibrium swelling experiments as well as the temperature and strain sweeps, the bound rubber content, filler‐filler bond strength, and cross‐linking density of NR/N330/MCBp are all superior to those of NR/N330/CBp, resulting in an outstanding comprehensive performance of NR/N330/MCBp composite. In particular, the 300% modulus and the tear strength rise by 43% and 14% respectively, surpassing even the system filled with N330. Finally, the mechanism of mechanical properties improvement in the NR/N330/MCBp composite is proposed: the strong filler‐filler bond is formed between the MCBp and N330 aggregates via molecular chains, and they are anchored on the MCBp and absorbed on the N330 simultaneously.