A new-type of composite combined by helical polysilane (HPS) and hollow spherical indium oxide (In 2 O 3 ) was designed and fabricated via solution blending. The hollow spheres constructed by In 2 O 3 particles were synthesized via a facile hydrothermal route where it demonstrated larger surface area, enabling the combination of HPS and In 2 O 3 more easily. Meanwhile, the synergetic effect between functional group of HPS and surface hydroxyl of In 2 O 3 improve the reduction of infrared emission. Consequently, the composite shows a superior low infrared emissivity performance at the value of 0.416 (8–14 μm), and the covering of HPS make the composite disperse well in the polar reagent. This work develops a feasible strategy that utilizes metallic oxide to design and synthesize hollow spherical matrix for preparing the low infrared emissivity materials.
Muyang Zhang,Yuming Zhou,Man He,Tao Zhang,Xiaohai Bu
A helical polysilane/multi walled carbon nanotubes composite was fabricated by wrapping helical HPS copolymer around the surface of modified nanotubes through surface oxidation. HPS was pre-polymerized by Wurtz-type coupling reaction in chloroform (CHCl3), demonstrating optical activity and adoption of a predominately signal-handed helical conformation. Various kinds of characterization including Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-vis), thermogravimetric analysis (TGA), circular dichroism (CD) and Raman spectroscopy have been utilized to demonstrate HPS noncovalently wrapped around the nanotubes to protect their original graphite structure. The wrapped HPS exhibited enhanced thermal stability and increased optical activity after wrapping. The infrared emissivity property of the composites at 8–14 μm was investigated as well. These results indicate the HPS/f-MWNTs composites possess a much lower infrared emissivity value (ε = 0.576) than raw MWNTs, which resulted from synergistic effect of the particular helical conformation of HPS and improved interfacial interaction between the organic polymers and inorganic nanoparticles.
Muyang Zhang,Yuming Zhou,Man He,Tao Zhang,Xiaohai Bu
The novel single-handed helical polysilanes (HPS), poly[di-n-hexylsilane-co-(methoxycarbonyl ethyl propyl ether)methylsilane] were synthesized by the Wurtz-type coupling of the chiral functional monomer, dichloro(methoxycarbonyl ethyl propyl ether)methylsilane (DCMMS). The monomer was prepared by the hydrosilylation reaction of methyl (S)-2-(allyloxy)propanoate. The chemical structure of HPS was confirmed by 1H, 13C and 29Si nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-Vis) and circular dichroism (CD). The weight distributions and crystallinity of the polysilanes were demonstrated by gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and polarized light microscopy (POM), respectively. The single-handed helical characterization and polymerization degree of the new-typed polysilanes could be controlled by the co-monomers of DCMMS and di-n-hexyldichlorosilane (DCDHS), respectively. Furthermore, the infrared emissivity values (0.598 at 8–14 μm) of HPS were investigated by an Infrared Emissometer.
Radiation detection plays a crucial role in the construction and safe operation of nuclear facilities. Liquid scintillator is widely used in this field but its fluorescence-scintillation properties still require improvement to achieve high sensitivity detection at present. In this paper, a new liquid scintillator system is developed, which selects polysilane as the matrix, and aryl with electron repulsing/withdrawing groups as the grafting substituents. The conjugated structure between the Si–Si chain and the aryl scintillating group enables electron delocalization transfer, resulting in improved fluorescence emission spectra and scintillation sensitivity. Three aryl-grafted polysilanes with typical electron repulsing and withdrawing group are successfully synthesized by Grignard routes. The optical properties of the materials are evaluated through both molecular simulation and experimental measurements, to determine the electronic effect of aryl groups on the electron delocalization in modified polysilane scintillators. The scintillation count performance is also evaluated. In conclusion, polysilanes grafted with aryl groups can be utilized as a new type of liquid scintillator, and electron repulsing substituents could enhance the fluorescence-scintillation properties more effectively, which providing meaningful guidance for the further optimization of liquid scintillation composition .
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