Yingjun Li

Based on the principles of photon and matter attenuation, lead sulphide (PbS) has the potential for applications in radiation protection owed to its elevated atomic number and density. Achieving good dispersion stability of PbS powder in highly filled composites remains a challenge due to the inherent nature. Here, we proposed a solution to these issues for highly filled rubber‐based flexible wearable composites. PbS particles were firstly synthesized and subsequently surface‐modified with a titanate coupling agent (NDZ‐201) enhanced the interfacial compatibility with the rubber‐based. Then, highly filled PbS@NDZ‐201/chloroprene rubber (CR) composites were obtained by physical blending. Test results showed that these highly filled composites exhibited even distribution of PbS granule and favorable interface compatibility. All the prepared PbS@NDZ‐201/CR composites exhibit excellent mechanical properties. In comparison to pure CR, the mechanical properties of the 70 wt% filler‐modified powder composites remained at a high level, with a tensile strength of 7.51 MPa and an elongation at break of 670.11%, represented improvements of 155% and 105%, respectively. The mass attenuation coefficient and the γ‐rays shielding coefficients of 70 wt% PbS@NDZ‐201/CR composites reached 34.15% and 36.87%, respectively. In conclusion, this method is feasible for the preparation of highly filled radiation protective rubber‐based flexible wearable materials. Highlights: Introduction of PbS in the field of radiation protection. NDZ‐201 improved the interfacial compatibility of PbS with CR. The mechanical properties of the composites were improved after modification by NDZ‐201. Highly filled flexible wearable composites for radiation protection was successfully prepared.

The strategic alignment of nanoplatelets within polymer matrices is pivotal for the development of nanocomposites with superior gas barrier characteristics. In this work, the effect of lamellar particles orientation in polymer for gas permeation was demonstrated. The magnetic α‐Al₂O₃ (Al₂O₃@PDA‐Fe₃O₄) was first prepared by in situ growth of Fe₃O₄ nanoparticles immobilized on polydopamine (PDA)‐modified Al₂O₃ surface. Subsequently the orientation of magnetic α‐Al₂O₃ in brominated butyl rubber (BIIR) was achieved by modulating the applied magnetic field direction. Results show that the PDA, as the role of surface adhesive, not only anchored Al₂O₃ substrate but also bound ferric ions for the further in situ formation of Fe₃O₄, which ensured the physico‐chemical stability of the magnetic α‐Al₂O₃. Comparison of hydrogen permeation performance of composites with in‐plan, middle‐of plane and out‐of plane alignment demonstrated the effect of lamellar particles orientation. The Al₂O₃@PDA‐Fe₃O₄/BIIR composite with in‐plane alignment had the best hydrogen barrier property by a 50% reduction in hydrogen permeability coefficient compared to the neat BIIR, underscoring the critical role of particle orientation in enhancing the gas barrier properties of nanocomposites.Highlights: The structural stability of magnetic Al₂O₃ nanocomposites was enhanced by polydopamine (PDA). The composites with in‐plane alignment, middle‐of plane alignment and out‐of plane alignment were prepared by a magnetic field. The effect of lamellar particles orientation on gas permeation of polymer nanocomposites was studied. The composites with in‐plane alignment possesses the best gas barrier property.

As a “green” radiation protection material with the potential to replace lead oxide, bismuth oxide has more research applications in the field of γ protection. However, due to their different surface properties, there are compatibility and interaction problems between metal oxides and rubber. To enhance the performance of bismuth oxide in neoprene, Bi₂O₃@PCPA‐KH590 was prepared by coating bismuth oxide with polyphenol/polyamine and grafting KH590 on the surface of bismuth oxide. This allows for creating more active sites with the help of polyphenol/polyamine, enabling KH590 to be grafted onto bismuth oxide particles. The S functional group on the silane coupling agent is then cross‐linked with the rubber substrate, enhancing the dispersibility of the bismuth oxide powder. This improvement not only improves the dispersibility of the bismuth oxide powder but also enhances the mechanical properties of the rubber composite material. Compared with pure CR, the mechanical properties of 60 wt% filler‐modified powder composites can still be maintained at a high level, with the tensile strength reaching 12.83 Mpa. In sum, the proposed method appears feasible for preparing highly filled radiation protection rubber‐based materials.

In order to solve the problem of poor thermal conductivity of polymer‐based radiation shielding composite materials, h‐BN@PDA@PbWO₄ hybrid powders were prepared by combining h‐BN with high thermal conductivity and PbWO₄ with γ shielding. With the assistance of polydopamine, PbWO₄ particles were synthesized in situ on the h‐BN surface. The effects of h‐BN@PDA@PbWO₄ on thermal conductivity, γ‐ray shielding, and mechanical properties of chloroprene rubber were studied. The results showed that the hybrid particles had better dispersibility than the pure mixing of h‐BN and PbWO₄ in chloroprene rubber and significantly improved the thermal conductivity gamma‐ray shielding performance and mechanical properties of CR composites. When the filler content of the hybrid powder reaches 40 wt%, the thermal conductivity of the composite is about 3.16 times that of the pure CR. The γ shielding rates at 86.5 KeV and 105.3 KeV photon energies increase by 14.14% and 17.61% compared with the pure CR. Compared with pure CR, the tensile strength of the composites increased by 4.79 MPa, and the elongation at break decreased slightly. These were because h‐BN@PDA@PbWO₄ shows had an excellent synergistic effect in CR substrate. The new kind of CR/h‐BN@PDA@PbWO₄ composite can be used for thermal management and gamma shielding.

Graphene-based elastomer composites with a segregated structure were prepared by electrostatic self-assembly. The morphology and microstructures of the composites were characterised by scanning electron microscope (SEM) and transmission electrical microscope (TEM). The segregated network leads to a low gas permeability coefficient for BIIR composites. With the incorporation as low as 0.4 wt-% GTA-GO, the helium permeability coefficient decreased about 63% when compared with that of neat BIIR. The tensile strength and percentage elongation increased with an increase in the GTA-GO content. This is attributed to the complete exfoliation, uniform dispersion and the segregated structure of GTA-GO in the BIIR matrix. These results demonstrate that such electrostatic self-assembly method between latex and sheet-fillers is an effective strategy to design and produce polymeric nanocomposites with good gas barrier properties. The results will effectively promote the application of barrier polymer in the production of protective clothing, gas storage devices and coatings.

Alkynyl-functionalized graphene oxide (A-GO) is an integral part of the click chemistry of graphene. However, this kind of functionalization often occurs in organic solvent system. In this study, a simple method was used to prepare alkynyl-functionalized graphene oxide under mild and environmental-friendly conditions. The results showed that graphene oxide was successfully modified by propargylamine. When the mass ratio of graphene oxide to propargylamine is 1:4, the highest grafting rate is 4.91%. The resulting sample became rougher in microscopic morphology, but still had a lamellar structure. In addition, it can be obtained from XPS that in addition to the ring-opening reaction between the epoxy group and the amino group, there is also the interaction between the carboxyl group and alkynyl ammonium. The present work provides a facile and environmental-friendly strategy toward alkynyl-functionalized graphene oxide.

One effective measure of radioactive material purification is the use of strippable decontaminants, which effectively coat the pollutant, capture suspended particles in the air, and deposit them onto the surfaces of objects. However, there are some shortcomings in terms of film formation and peelability, such as a brittle coating and poor peelability. Therefore, in order to meet future military and emergency needs, this research investigated the influencing factors in the process of surface strippable decontamination. Experiments included tests for wettability, potential, particle size, strippable performance, tensile performance, ultraviolet transmittance reflectance, and film formation as well as image analysis of photomicrographs from an optical microscope system. These experiments indicate that the strippable decontaminant is a viable means of contamination removal.