Zhaobo Wang

Superhydrophobic materials have significant industrial application value in self-cleaning and oil–water separation. Thus, a β-nucleating agent–modified polypropylene (PP)/EPDM terpolymer thermoplastic vulcanizate (TPV) was fabricated, and a rough surface texture was constructed using metallographic sandpaper as a template. The resulting material exhibited superhydrophobicity, self-cleaning capability, and pressure-responsive oil–water separation performance. The results show that after hot-pressing PP/EPDM TPVs with W10 metallographic sandpaper, the surface contact angle of the TPVs increased to 154.3°, the sliding angle decreased to 3.1°, and the surface energy decreased to 12.2 mN·m ⁻¹ , indicating a remarkable improvement in superhydrophobic performance. Furthermore, with the incorporation of a β-nucleating agent into the PP phase of PP/EPDM TPVs, the loose stacking of β-crystal molecular chains facilitated plastic deformation, leading to a further enhancement of surface roughness after sandpaper templating. Consequently, the surface contact angle increased to 157.8°, the sliding angle decreased to 2.8°, and the surface energy was reduced to 11.3 mN·m ⁻¹ . Under both sliding and rolling self-cleaning test modes, the TPVs with β-nucleating agent exhibited excellent self-cleaning behavior. In oil–water separation experiments, the β-nucleating agent–modified superhydrophobic TPV films demonstrated rapid separation, high selectivity, and pressure-responsive characteristics across various oil–water mixtures. The critical pressure difference between oil and water phases reached as high as 4.10 kPa, and the separation efficiency remained >95.0%, even under strong suction forces. New insights are presented on the development of efficient and sustainable materials for oil–water separation and self-cleaning applications.

Novel thermoplastic vulcanizates (TPVs) based on a coordination-crosslinking system composed of ethylene-vinyl acetate copolymer (EVA), nitrile butadiene rubber (NBR) and liquid nitrile butadiene rubber (LNBR) were prepared via dynamic vulcanization, and a simple and efficient strategy for fabricating thermally responsive shape-memory polymers (TSMPs) was developed. After etching, both EVA/NBR/LNBR TPV and EVA/NBR TPV exhibited distinct sea-island surface microstructures. The incorporation of LNBR into NBR effectively reduced the particle size of the cross-linked rubber phase in EVA/NBR/LNBR TPV, significantly enhancing the mechanical strength of the TPV. EVA, serving as the continuous phase, mainly contributed to the shape fixity capability of the dynamic vulcanizate system. In contrast, the highly elastic NBR/LNBR rubber particles acted as the dispersed phase, providing the primary driving force during shape recovery. The introduction of LNBR into NBR resulted in a slight decrease in the shape-fixity ratio (SF%) of EVA/NBR/LNBR TPVs, but led to a remarkable increase in shape-recovery ratio (SR%). By adjusting the mass ratio of EVA to the NBR/LNBR blend, the shape fixity and shape recovery behaviors of the EVA/NBR/LNBR TPV can be effectively controlled under thermal stimulation. Increasing the EVA content in the TPV improved the SF% but significantly reduced the SR%. The shape-memory performance of EVA/NBR/LNBR TPVs was strongly temperature-dependent. When both the fixing and recovery temperatures were set to 85°C, the EVA/NBR/LNBR TPV with a mass ratio of 80/20 exhibited SF% and SR% values above 94.0%, with a shape-recovery time of 15∼20 s, demonstrating excellent shape-memory behavior.

The non-isothermal crystallization kinetics of both pure ethylene-vinyl acetate copolymer (EVA) and EVA/butadiene rubber (BR) thermoplastic vulcanizate (TPV) which was prepared through dynamic vulcanization were investigated via differential scanning calorimetry (DSC). The mechanism of non-isothermal crystallization was analyzed using the Avrami model modified by the Jeziorny method, along with the Ozawa and Mo methods. The results demonstrated that the non-isothermal crystallization behavior of both EVA/BR TPV and pure EVA could not be accurately described by the Ozawa method. In contrast, the Jeziorny and Mo methods provided a more precise representation of the crystallization behavior. Data analysis revealed that EVA exhibited a faster crystallization rate compared to EVA/BR TPV. In contrast, the initial crystallization temperature of EVA was lower than that of the EVA/BR TPV. In conclusion, BR served as a nucleating agent in EVA/BR TPV, facilitating the nucleation of the EVA phase. However, due to the steric hindrance effects, the EVA crystal growth process was hindered by the existence of BR phase.

Thermoplastic vulcanizates (TPVs) based on ethylene-vinyl acetate copolymer (EVA)/nitrile butadiene rubber (NBR)/liquid nitrile rubber (LNBR) were prepared using a dynamic vulcanization method with a copper sulfate (CuSO₄) coordination cross-linking system. The microstructures of EVA/NBR TPV and EVA/NBR/LNBR TPV were analyzed using field emission scanning electron microscopy (FE-SEM). The mechanical properties and non-isothermal crystallization kinetics of EVA/NBR/LNBR TPV, EVA/NBR TPV and pure EVA were investigated using a universal testing machine and differential scanning calorimetry (DSC), respectively. The experimental results demonstrated that the incorporation of LNBR enhanced the mechanical properties of the EVA/NBR TPV significantly. The size of the crosslinked NBR particles were refined with the incorporation of LNBR in TPV, which influenced the non-isothermal crystallization behavior of the EVA phase. Data analysis revealed that the crystallization behavior could be characterized by the Jeziorny and Mo methods effectively. The NBR phase was found to promote nucleation of the EVA matrix while simultaneously inhibiting the growth of EVA crystals. The existence of LNBR in TPV further enhanced the nucleation-promoting effect, while the influence on weakening the inhibition of crystal growth was limited.

A simple and effective strategy for preparing thermo-responsive shape memory polymers (TSMPs) can be designed where the novel TSMPs based on ethylene-methyl acrylate copolymer (EMA) and chlorinated polyethylene rubber (CR) thermoplastic vulcanizates (TPVs) were prepared using dynamic vulcanization. The morphology of the EMA/CR TPVs exhibited a sea-island structure obviously; moreover, the EMA served as the continuous phase and mainly provided the shape fixation (SF) capability of the blend, while the highly elastic CR was acted as the dispersed phase and provided the primary driving force during the shape recovery (SR) process. The SF and SR behaviors of the EMA/CR TPVs can be effectively controlled by varying the weight ratio of EMA/CR blends. Increasing the weight ratio of EMA/CR, the SF% of the EMA/CR TPVs was enhanced while the SR% was decreased remarkably. The shape memory behaviors of EMA/CR TPVs were significantly influenced by temperature. Notably, when the fixation and recovery temperatures were all set at 95°C, both the SF% and SR% of the EMA/CR TPVs with a weight ratio of 80/20 exceeded 95%, and the SR time was 15∼20s, demonstrating the excellent shape memory property.

Thermoplastic vulcanizate (TPV) made from the ethylene-vinyl acetate copolymer (EVA)/nitrile rubber (NBR) blend was fabricated using the dynamic vulcanization method. Differential scanning calorimetry (DSC) was utilized to analyze the nonisothermal crystallization kinetics of both pure EVA and EVA/NBR TPV. The nonisothermal crystallization mechanism was evaluated using the Avrami method modified by Jeziorny, the Ozawa method and the Mo method. The results demonstrate that the nonisothermal crystallization of both pure EVA and EVA/NBR TPV can be adequately described by the Avrami method modified by Jeziorny and the Mo method, while the Ozawa method is not applicable. By elevating the cooling rate, there was a reduction in the crystallization temperature and t_1/2 for both pure EVA and EVA/NBR TPV, while the degree of crystallization increased. At the same cooling rate, the crystallization temperature of the EVA/NBR TPV was found to be higher than that of the pure EVA, suggesting that the presence of NBR facilitated the nucleation of the EVA matrix within the EVA/NBR TPV. Moreover, a steric hindrance effect existed in the NBR phase of EVA/NBR TPV at the same cooling rate, resulting in a larger t_1/2 compared to that of the pure EVA, indicating hindered crystal growth.

In recent years, with the continuous discharge of wastewater, which has caused serious environmental pollution, it is a task to separate oil or water from wastewater. Therefore, an efficient and low‐cost oil–water separation method is needed to separate the oil–water mixture. Here, a superhydrophobic/superoleophilic low density polyethylene/styrene‐butadiene rubber (LDPE/SBR) thermoplastic vulcanizate (TPV) film (oil contact angle of 0° and water contact angle of 161.1° ± 1.7°) is prepared using an etched aluminum foil as a template and applied to a laboratory‐assembled oil–water separation device, which is a new method for oil–water separation via a pressure response valve. The LDPE/SBR TPV film is rolled up and stuffed into the through‐valve, and the gap between the films is used as the pressure response channel for oil and water separation, thus achieving oil and water separation. When the film gap is 25 or 50 µm, the separation efficiency of TPV film is greater than 99% with the variation of external pumping force, indicating that this method can achieve complete oil–water separation under a suitable external pumping force. This functional TPV film has good recyclability, environmental stability, chemical stability, mechanical durability, as well as thermal stability, which makes it have great application potential.