The global water crisis is becoming more and more serious, and solar steam generation has recently been investigated for clean water production and wastewater treatment. However, the efficiency of solar vapor transfer is still low. It is a great challenge to find photothermal materials which simultaneously have high energy transfer efficiency, facile production, and are low cost. To address this, we propose a method which is simple, low cost and suitable for large-scale preparation to fabricate the photothermal materials based on using recycled natural rubber sponge (NRS) coated with polydopamine (PDA). X-ray photoelectron spectroscopy analysis confirmed that when the PDA coated the surface of the NRS, the hydrophilicity of the sponge was significantly improved. Scanning electron microscopy characterization showed that the PDA-coated natural rubber sponge (PNRS) maintained the porous 3D skeleton of the pristine sponge. As a result, PNRS exhibits excellent photothermal properties, a very high evaporation rate of 1.35 kg m⁻² h⁻¹, and an energy transfer efficiency of 84.6% can be achieved under a light intensity of 1 sun (1 kW m⁻²). It is worth noting that the vapor generation of PNRS is still at a high level with 1.06 and 1.09 kg m⁻² h⁻¹ in the corrosive liquids of 1 M H₂SO₄ and 0.5 M NaOH, respectively. The photothermal materials based on using recycled NRS have good application prospects in seawater desalination and the purification of wastewater, which also provides a new method for the recycling of waste NRS.

The coagulation of fresh latex is one of the critical processes that impacts rubber quality during natural rubber processing. Constitutive relationships are the basis for the study of the mechanical properties of rubber materials and serve as a prerequisite for material simulation studies. However, studies on the effect of different coagulation methods on natural rubber constitutive relationships have yet to be carried out, and the current models used for natural rubber constitutive relationships need to be improved. In order to investigate the effects of different coagulation methods on the hyperelastic properties of natural rubber, the impact of natural coagulation, enzyme coagulation, acid coagulation, microbial coagulation, and enzyme-assisted microbial coagulation on the hyperelastic constitutive relationship of natural rubber were analyzed in detail based on tensile experiments and the Yeoh model. The results show that after introducing a strain rate-related factor, the Yeoh model can describe well the mechanical behavior of natural rubber carbon black composites in different deformation regions, and the rubber, studied with varying coagulation methods, exhibits different mechanical properties in different deformation regions. This study provides new evidence for the study of high-performance natural rubber and serves as a reference for process selection in the primary processing of natural rubber.

Natural rubber (NR) exhibits good elasticity, flexural resistance, wear resistance, and excellent mechanical properties, and it has been widely used in aerospace, transportation, medical, and health fields. For NR, however, the resistance to thermal-oxidation and ozone aging is fairly poor. Although aging properties of NR can be significantly improved with the incorporation of chloroprene rubber (CR) according to some references, the miscibility between NR and CR, the morphologies of the binary blends, and so on are revealed ambiguously. In this work, molecular dynamics simulation (MD) and dissipative particle dynamics (DPD) simulation were carried out to predict the compatibility between natural rubber and chloroprene rubber in view of Flory–Huggins parameters. The morphologies of the blends were obtained with the use of the DPD method. The simulation results were furtherly examined by means of Fourier transform infrared spectroscopy (FT-IR) and dynamic mechanical analysis (DMA). It was found that the miscibility between NR and CR is poor. Nevertheless, the miscibility could be improved when the content of CR is 50% or 90%. In addition, spinodal decomposition with a critical temperature of 390 K would take place according to the phase diagram. Microphase structure such as spherical, lamellar, and bicontinuous phases can be found with different contents of CR in the blends with the results of morphologies analysis.

Formaldehyde is a volatile organic compound that may remain in, or be released from, epoxy adhesive formulations. Prolonged or high-level exposure can cause chronic respiratory injury and elevate cancer risk. Accordingly, developing epoxy curing agents from renewable bioresources without introducing formaldehyde is of significant importance for safeguarding human health and reducing environmental impacts. In this study, a biobased phenalkamine curing agent was synthesized from cardanol via a Mannich reaction incorporating 1,4-butanediamine and citronellal, and subsequently combined with bisphenol A diglycidyl ether to construct an epoxy adhesive system. The overall performance was systematically assessed by differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and mechanical testing. The adhesive system was curable at 26 °C, with an optimal curing temperature of 88 °C. The room-temperature cured specimens exhibited a tensile strength of 1.73 MPa, an impact strength of 32.59 kJ·m^–2, and a lap-shear strength of 3.28 MPa. After stepwise thermal curing, the corresponding values were 5.06 MPa, 50.10 kJ·m^–2, and 3.22 MPa, respectively. Dynamic mechanical analysis revealed glass-transition temperatures (T _g) of 38.9 and 48.8 °C for the room-temperature cured and stepwise thermally cured groups, respectively. Vertical burning tests showed rapid self-extinguishment of approximately 3 s and no ignition-causing dripping, indicating favorable flame retardancy of the adhesive system. This work provides experimental evidence supporting the development of formaldehyde-free, low-environmental-burden, room-temperature-curable epoxy adhesive systems.

Hydrophobic melamine sponges were prepared via a facile one-step reaction of three isocyanates (i.e., cyclohexyl isocyanate, octadecyl isocyanate, and butyl isocyanate) with hydroxymethyl groups located on the melamine sponge. The modified sponges were characterized by infrared spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, and contact angle tester. The results showed that the water contact angle of the modified sponges reached around 140°, and the sponges had a three-dimensional network with high porosity, which can be used as efficient adsorbents to adsorb a variety of oils or organic solvents with different viscosities and densities. The experiments found that the modified sponges had good oil absorption performance, with 62–143 times their weight, for different oil and organic solvents. In addition, after being soaked in strong acid, strong alkali, and 3.5% sodium chloride aqueous solutions for 72 h, the modified sponges’ absorption capacity remained high.