Search

Highlights Highly filled polymer fibers offer huge promise for radiation protection safety and wear comfort of personal protective equipment (PPE) in radiation environments. However, it usually sacrifices mechanical properties that directly related to practical usability. Here, as high as 75 wt% PbWO4 (PWO) particles have been filled in polyvinyl alcohol (PVA) fiber via tailoring their size and shape for enhanced γ‐rays shielding and good mechanical properties. Clearly shown that 0 dimensional (0‐D) PWO exhibits better dispersion and compatibility between the interfaces than 1‐D PWO in highly filled PVA fibers. In addition, 70 wt% 0‐D PWO/PVA fibers display better mechanical properties than 70 wt% 1‐D PWO/PVA fibers. Note that 75 wt% 0‐D PWO/PVA fibers show 1.02 cN/dtex of tensile strength. However, 75 wt% 1‐D PWO/PVA fibers fail to be fabricated smoothly. Importantly, the overlapped fabrics with 75 wt% 0‐D PWO/PVA fibers display 43.05% of γ‐ray shielding (105 keV) meanwhile it offers good air and water vapor permeability for wear comfort. The superior γ‐ray shielding ascribes the polymer fibers with the higher filling in comparison with its counterpart, which provides a practical means to design radiation protection safety and wear comfort of articles. This work breaks the upper limit of filling in polymer fibers Filler structure can weigh the integrated properties of polymer fibers. 0‐D PWO particles promote interfacial compatibility in highly filled fibers. Radiation protection safety and wear comfort of articles tend to be designed. [ABSTRACT FROM AUTHOR]

Polymer dielectrics have gained significant usage in electrical engineering due to their unique merits, such as good flexibility, easy processing, and low cost. However, it is a huge challenge that polymer dielectrics maintain high breakdown strength meanwhile high permittivity for enhanced energy density. Here, sandwiched polymer films are constructed for enhanced energy density. Increased permittivity has been achieved via blending BaTiO3@polyfluorosiloxane with a polymer as the top and bottom layer. Furthermore, the neat polymer as the middle layer is without critically sacrificing breakdown strength. The energy storage density increases from 7.8 J/cm3 of the neat polymer to 10.41 J/cm3 of the sandwich structure at 460 MV/m. This research offers a feasible route for fabricating capacitive films with enhanced energy density. [ABSTRACT FROM AUTHOR]

Achieving lead-free flexible materials with excellent γ-ray shielding as well as good mechanical properties are of significance to radiation protection safety and wear comfort of wearable articles. In this paper, polydopamine (PDA) is coated on Bi2O3 particles to form a typical core–shell structure Bi2O3@PDA, which is used to intensely bond bismuth oxide (Bi2O3) with chloroprene rubber (CR). It promotes the interface interaction between Bi2O3 and CR matrix, leading to the uniform dispersion of the filler and rich interfacial compatibility in CR/Bi2O3@PDA composite with as high as 50 wt% filling. Furthermore, 50 wt% CR/Bi2O3@PDA composite displays 53.6% shielding rate for 105 keV γ-rays. Meanwhile, its tensile strength and elongation at break are 9.6 MPa and 1424.8%, respectively, which are without sacrificing too much in comparison with the neat rubber. We propose a versatile route to prepare superior integrated properties of flexible materials, which can be used as wearable articles for radiation shielding. [ABSTRACT FROM AUTHOR]

Improved dielectric constant and breakdown strength facilitates excellent energy storage density of polymer dielectrics, which is positive to miniaturize dielectric capacitors in electronic and electrical systems. Although coating polar substances on nanoparticles enhances the dielectric constants of polymer nanocomposites, it usually causes local electric field concentration, leading to poor breakdown strength. Here, fluoropolymers with tailorable fluorine content (PF0, PF30 and PF60) are coated on BaTiO3 (BT) nanoparticles to construct typical core–shell structures that are further blended with poly(vinylidenefluoride-co-hexafluoropropylene) (P(VDF-HFP)) to obtain BT@PF/P(VDF-HFP) nanocomposites. Uniform dispersion of nanoparticles and excellent compatibility of interfaces are observed for the samples. In addition, the dielectric constant gradually increases from 8.03 to 8.26 to 9.12 for the nanocomposites filled with 3 wt% BT@PF0, BT@PF30 and BT@PF60, respectively. However, 3 wt% BT@PF30/P(VDF-HFP) has the highest breakdown strength (455 kV mm−1) among the nanocomposites, which is as good as neat P(VDF-HFP). More importantly, BT@PF30 rather than BT@PF60 possesses the maximum discharged energy density (11.56 J cm−3 at 485 kV mm−1), which is about 1.65 times that of neat P(VDF-HFP). This work proposes a facile experimental route to optimize the dielectric constants of the shell layer to couple the dielectric constants between the nanoparticles, shell layer and polymer matrix, which contributes to alleviating the local electric field concentration for excellent breakdown strength and electrical energy storage of polymer nanocomposites. [ABSTRACT FROM AUTHOR]

Radiation protection safety and wear comfort of personal protective equipment (PPE) are of vital importance to nuclear personnel involved. Unfortunately, it is difficult for current PEE to meet the increasing requirements, which causes tremendous threats to health and reduced working efficiency. Here, a highly filled polymer fiber for textile‐based PPE to deal with the dilemma is put forward. PbWO4 (PWO) particles are superficially modified with styrene maleic anhydride (SMA) and then titanate coupling agent (bis(dioctyl pyrophosphate) ethylene titanate (BPET)) to form PWO@SMA‐BPET. After that, as high as 70 wt% PWO@SMA‐BPET/polyvinyl alcohol (PVA) fibers are obtained by solution blending and wet spinning in succession. Synergistic effects of surface modification with SMA and BPET lead to uniform dispersion PWO particles and good compatibility of interfaces in highly filled fibers. Importantly 36.6% γ‐ray (105 keV) shielding has been detected at three‐layer fabrics with 70 wt% PWO@SMA‐BPET/PVA fiber. Besides, the fabrics also display 116 mm s−1 of air permeability and 5388 g m−2 24 h of water vapor permeability, respectively. This work discloses synergistic effects on surface modification of high loading inorganic particles in polymer fibers, which give a further boost to γ‐ray shielding safety and wear comfort of PPE. [ABSTRACT FROM AUTHOR]

Significantly enhanced dielectric constant and energy storage density positively facilitate miniaturising dielectric capacitors for various applications in electronics and electrical devices. Herein, a fluoropolymer is coated on BaTiO3 (BT) nanoparticles to form a core–shell structure (BT@PF80), which is used as additional dipoles to enhance the dielectric constant and energy density of polymer nanocomposites. Characterizations with various techniques show uniform dispersion of nanoparticles and good compatibility of interfaces in polymer nanocomposites. Furthermore, the dielectric constant increases from 7.85 of neat polymer to 9.43 of the nanocomposites filled with BT@PF80 while the dielectric loss further decreases from 0.05 to 0.04 at 1 KHz. In addition, 7.79 J cm−3 of energy density is achieved at the nanocomposites filled with BT@PF80, which is 2.65 times higher than that of the neat polymer. This work presents a simple and effective means to enhance dielectric constant and energy density, which tends to fertilize the fabrications of polymer dielectrics for electric energy storage. [ABSTRACT FROM AUTHOR]

Rubber composites with excellent radiation shielding and flexibility are extremely important to personal protective equipments (PPEs) for protecting workers from radiation hazards, especially for mixed radiations. It is, however, challenging to achieve uniform dispersion of fillers and good compatibility of the interfaces in highly‐filled rubber composites that are closely related to their physical properties. In this article, lead borate@polydopamine (PBO@PDA) core–shell particles are chemically bonded with silicone rubber (SR) for co‐shielding of neutron and γ‐rays. Uniform dispersion of the core–shell particles and good compatibility of the interfaces give rise to enhanced flexibility of the rubber composites. Particularly, the SR composite with 40 wt% PBO particles displays increases of 106% in elongation at break and 490% in tensile strength to neat SR. Furthermore, the mass attenuation coefficient of γ‐rays (105 KeV) reaches 2.35 and the thermal neutron absorption rate (0.025 eV) of is 76.9%. This work takes into account the balance between radiation shielding and flexibility of rubber composites, which provides a facile strategy to fabricate excellent integrated properties of flexible materials for shielding mixed neutron and γ‐rays. [ABSTRACT FROM AUTHOR]

Integrating high-loading dielectric nanoparticles into polar polymer matrices potentially can profit the intrinsic polarization of each phase and allow for greatly enhanced dielectric properties in polymer nanocomposites. It is however challenging to achieve desirable highly filled polar polymer composites because of the lack of efficient approaches to disperse nanoparticles and maintain interfacial compatibility. Here, we report a versatile route to fabricate highly filled barium titanate/fluorinated silicone rubber (BT/FSR) nanocomposites by "thiol–ene click" and isostatic pressing techniques. The loaded BT nanoparticles (from 82 wt% to 90 wt%) are chemically bonded with FSR in the nanocomposites. The existence of the polar group (–CH2CF3) of the polymer matrix does not affect the uniform dispersion of the nanoparticles or the good interfacial compatibility. The 90 wt% BT/FSR nanocomposite shows the highest dielectric constant of 57.8 at 103 Hz, while the loss tangent can be kept below 0.03. Besides, BT/FSR nanocomposites display higher breakdown strength than BT/SR nanocomposites. This work offers a facile strategy towards superior dielectric properties of polymer nanocomposites. [ABSTRACT FROM AUTHOR]

Dielectric nanomaterials offer great promise for diverse technological applications such as capacitors, actuators, and sensors. Unfortunately, the exploitation of desirable dielectric properties in polymer nanocomposites is a great challenge due to lack of efficient routes to achieve uniform dispersion of nanoparticles and good compatibility of interfaces at high nanoparticle loadings. A dilemma between the nanofiller loading and dispersion as well as interfacial compatibility makes it impossible to fully exploit the intrinsic polarization of the nanoparticles. Herein, we solve such a dilemma and fabricate highly filled barium titanate/silicone rubber (BT/SR) nanocomposites through chemically bonding BT nanoparticles with SR by "thiol–ene click" and isostatic pressing techniques. BT loading varies from 88 wt% to 97 wt% without compromising the uniform dispersion quality and good interfacial adhesion with the SR matrix. The 90 wt% BT nanocomposite shows an optimum dielectric constant as high as 55, while its loss tangent can be kept as low as 0.019 at 103 Hz. Meanwhile, it displays good stability of dielectric properties from room temperature up to 100 °C. In addition, the breakdown strength just decreases slightly compared to neat SR (97 MV m−1) but is still beyond 75 MV m−1. The present work provides a facile strategy towards superior dielectric polymer nanocomposites. [ABSTRACT FROM AUTHOR]