Natural rubber (NR) composites have been widely applied in damping products to reduce harmful vibrations, while rubber with only a single composition barely meets performance requirements. In this study, rubber blend composites including various ratios of NR and styrene butadiene rubber (SBR) were prepared via the conventional mechanical blending method. The effects of the rubber components on the compression set, compression fatigue temperature rising and the thermal oxidative aging properties of the NR/SBR blend composites were investigated. Meanwhile, the dynamic mechanical thermal analyzer and rubber processing analyzer were used to characterize the dynamic viscoelasticity of the NR/SBR blend composites. It was shown that, with the increase in the SBR ratio, the vulcanization rate of the composites increased significantly, while the compression fatigue temperature rising of the composites decreased gradually from 47 °C (0% SBR ratio) to 31 °C (50% SBR ratio). The compression set of the composites remained at ~33% when the SBR ratio was no more than 20%, and increased gradually when the SBR ratio was more than 20%.

Considering the dilemma of obtaining economic and high-performance composites based on non-polar and main-chain-saturated ethylene propylene diene monomer rubber (EPDM), we proposed an effective and universal filler modification and nanocomposite preparation method. Specifically, the montmorillonite (MMT) surface was coated with polydopamine (PDA) to obtain DMMT, which was confirmed by XRD, XPS, FTIR, and TGA. After compounding DMMT gel with the solid EPDM via the gel compounding method, a silane coupling agent, vinyltrimethoxysilane, was introduced to construct covalent interactions between rubber and filler. Compared with the unmodified MMT filler EPDM, the EPDM/DMMT nanocomposite showed much fewer filler aggregates in the matrix. The highest tensile strength of the composites reached 6.5 MPa with 10 phr DMMT, almost 200% higher than that of pure EPDM.

Phosphotungstic acid (HPW) can retain water in proton exchange membranes to increase proton conductivity; however, its water-soluble nature limits further application. In this work, we combined HPW and graphitic carbon nitride (g-C₃N₄) via sintering to prepare water-insoluble hybrids (HWN), where HPW was chemically linked to g-C₃N₄ to fix HPW. Then, HWN fillers were added to a sulfonated polyether ether ketone (SPEEK) matrix to prepare composite membranes. The conductivity of the composite membrane with 10 wt% HWN is up to 0.066 S cm⁻¹ at room temperature, which is 53% higher than that of the SPEEK control membrane (0.043 S cm⁻¹). The composite membrane also showed stable proton conductivity after being immersed in water for 2000 h. Therefore, our study demonstrates that preparing water-insoluble nanofillers containing HPW components through sintering is a promising approach.

The positive matrix factorization (PMF) model is widely used for volatile organic compound (VOC) source apportionment, yet its assumption of chemical stability conflicts with reactive transport processes. To address this, we developed a two-stage approach that quantifies photochemical aging by separately identifying distinct atmospheric processing phases. Analyzing one year of VOC measurements in Shanghai, we resolved five factors, including diesel exhaust, industry/solvents, and aged VOCs. By correlating factor contributions with OH radical reaction rate constants (k_OH), we determined transport times for primary emissions (stage I) and the ultimate aging state (stage II). Correcting for these stages revealed that conventional ozone formation potential (OFP) estimates account for only 15% and 42% of the actual potential at QP and PD, respectively, when accounting for photochemical loss. This framework provides a more accurate representation of initial emission profiles, demonstrating that pre-receptor processes are critical for characterizing the true impact of VOC sources on urban air quality.