Shahid Khan,Chaoyan Fang,Yecheng Ma,Mahmood ul Haq,Mohammad Nisar,Gang Xu,Yong Liu,Gaorong Han
The aim of the study was to determine the effect of inorganic core-shell SiO2 nanoparticles modified with polymethyl methacrylate (PMMA) layer, on the optical and electrochemical properties of poly vinylidenefluoride-co-hexafluoropropylene (PVDF-HFP) gel polymer electrolyte (GPE). The core-shell SiO2 nanoparticles were first modified with PMMA to improve its dispersibility and compatibility in the polymer matrix. The morphology and structural properties of the core-shell SiO2 nanoparticles before and after modification were characterized by XRD, FTIR and SEM analysis. Then the modified SiO2 nanoparticles were used to prepare the composite GPE, composed of chemically modified core-shell structured SiO2-PMMA and PVDF-HFP polymer matrix. The transformation of nano-silica to SiO2-PMMA nanoparticles shows the better compatibility of PMMA and PVDF-HFP that favours the silica to be well dispersed in the organic matrix and significantly improve the doping effect. Various concentrations of modified SiO2-PMMA were used to dope PVDF-HFP GPEs. The results indicate that the 10% doping shows the highest ionic conductivity i.e. 2.22 × 10−3 s cm−1. In addition, the composite GPEs show the high transmittance and good thermal stability; therefore it can add important insight into developing high-performance materials for electrochromic devices.
Heat-resistant, highly surface-hardened, and transparent composites of poly(methylmethacrylate) (PMMA) play a significant role in modern devices. However, conventional PMMA-based composites with high nanoparticle loadings often compromise transparency for high surface hardness and heat resistance due to nanoparticle aggregation and poor interfacial compatibility. In this work, we successfully fabricated an exceptional composite (MSiO 2 /PMMA composites) with high transparency, superior heat resistance, and high surface hardness using γ-ray irradiation-induced polymerization of methyl methacrylate (MMA) containing uniformly dispersed SiO 2 that was modified by 3-methacryloxypropyl trimethoxysilane and trimethylchlorosilane. Specific silanes were utilized for polarity regulation to reduce the agglomeration of SiO 2 nanoparticles and improve compatibility with MMA. Compared to pure PMMA, the 40-MSiO 2 /PMMA composite sample exhibited significantly improved thermal stability in terms of the temperature at 10% weight loss ( T 10% ), glass transition temperature ( T g ), and decreased coefficient of thermal expansion (CTE). Furthermore, this composite achieves a very high surface hardness (pencil hardness of 6H versus H for pure PMMA) while maintaining transparency similar to PMMA. These MSiO 2 /PMMA composites open up new avenues to enhance the performance and durability of materials used in various industries such as electronics, optics, automotive, and aerospace.
Wu Gang,Guo Shuang,Yin Yue,Sun Gang,Zhong Yongjian,You Bo
This paper presented a facile method to prepare the silica/poly (methyl methacrylate) (SiO 2 /PMMA) nanocomposite hollow microspheres (NHSs) which were firstly applied to fabricate the light diffusion films with high transmittance and high haze simultaneously. The SiO 2 /PMMA NHSs were prepared via in situ diffusion of polymeric core into the voids of inorganic shell under strong electrostatic attraction. The hollow morphologies of the microspheres were studied under the help of transmission electron microscope and scanning electronic microscope. The formation process of these NHSs could be elucidated using a mechanism similar to the Kirkendall effect. These NHSs were firstly used to produce light diffusion films by blending with polyacrylate latex. The new kind of light diffusion films with micro-nano structure were built by casting the SiO 2 /PMMA NHSs/polyacrylate coatings on optical-grade PET films. The transmittance and haze value of the light diffusion films were tested by a haze meter and application on a LED lamp. As a result, the coating films with NHSs had the best light diffusion properties compared to those films with no spheres or nanocomposite solid microspheres, which indicated that the light diffusion films with NHSs were promisingly applied in LED illumination, photoelectric devices and large area LCD.
Li Jian,Hu Rong,Zhou Hongming,Tao Shengdong,Wang Ya
Polymer electrolytes have attracted widespread attention owing to their low cost and excellent processability. However, polymer electrolytes have yet been widely applied in commercial batteries due to their own drawbacks, such as weak mechanical properties and lower ionic conductivity. In this paper, poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was blended with polyethylene oxide (PEO) and polymethyl methacrylate (PMMA) to build a novel polymer matrix, and SiO 2 @PMMA was doped into blended polymer matrix to form a composite polymer electrolyte named CPE-(SiO 2 @PMMA). The CPE-(SiO 2 @PMMA) performs superior electrochemical performance, such as a favorable electrochemical stability window (4.7 V vs Li/Li + ), decent ionic conductivity (8.54 × 10 –5 S cm −1 at 60 ℃), and excellent interface stability. The lithium metal battery LiNi 0.8 Co 0.1 Mn 0.1 O 2 /CPE/Li was fabricated to build a high specific energy system, which performs excellent cycling and C-rate performance compared to others polymer electrolytes. Capacity retention of LiNi 0.8 Co 0.1 Mn 0.1 O 2 /Li cell with CPE-(SiO 2 @PMMA) achieves 81.6% after 100 cycles, while CPE was broken with 100 cycles unfinished. All of the above favorable properties proved that PVDF-HFP/PMMA/PEO polymer matrix with SiO 2 @PMMA doped is a promising electrolyte candidate for flexible lithium metal batteries.
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