CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 10
·1431-1441
·
IF 1.835
Zhao Wen,Lin Bao-ping,Zhang Xue-qin,Sun Ying,Yang Hong
We describe in this work an alkyne-hydrosilylation approach to synthesize a series of novel polysiloxane side-chain LCPs attaching end-on or side-on mesogenic side groups. Their properties are characterized by NMR, FTIR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarized optical microscopy and small-angle X-ray scattering. These obtained alkenylsilane linked novel LCPs exhibit higher glass transition temperatures and clearing points, and especially display the tendency of forming smectic phases, in strong contrast with the nematic phases of their comparative conventional alkylsilane linked analogues, which manifests more rigid features of the alkenylsilane linkages and their significant influence on the mesomorphic properties.
研究领域:
高分子化学
·
材料科学
·
液晶材料
·
有机合成
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Wenjing Zou,Ping Yang,Lifu Lin,Yehua Li,Shanghua Wu
Silicon nitride (Si 3 N 4 ) slurries with high solid loading, low viscosity and good stability is difficulty prepared, due to low intrinsic surface charge and a large refractive index (RI) difference between Si 3 N 4 powder and resin. In this paper, the curing behavior of Si 3 N 4 slurry with different functional group and RI of resin monomer were systematically researched, and then the kind and optimum content of dispersant were investigated. Subsequently, a high solid loading Si 3 N 4 slurry (44 vol%) with good curing behavior, low viscosity and favorable stability was successfully prepared. Lastly, the dense Si 3 N 4 ceramic parts were fabricated by the suitable Si 3 N 4 slurry (44 vol%) via stereolithography . After debinding and sintering process , the relative density and flexural strength of Si 3 N 4 ceramic were 98.28% and 800 ± 27.28 Mpa, respectively.
研究领域:
材料科学
·
制造工程
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Fuming Liu,Mei Luo,Keliang Wang,Ziwei Li,Fei Liu,Min Li
Electrochemical CO 2 reduction reaction (CO 2 RR) is one of the most attractive measures to achieve the carbon neutral goal by converting CO 2 into high-value chemicals such as formate. Si in Bi silicates is promising to enhance CO 2 adsorption and activation due to its strong oxygenophilicity. Whereas, its role in boosting CO 2 RR via the cheap Bi-based catalysts is still not clear. Herein, we design CNT@Bi silicates catalyst, demonstrating the highest FE HCOOH of 96.3 % at −0.9 V vs . reversible hydrogen electrode with good stability. Through X-ray photoelectron spectroscopy (XPS), in-situ Attenuated Total Reflectance-Fourier Transform Infrared ( In-situ ATR-SEIRAS) experiments, and Density Functional Theory (DFT) calculations, the role of Si in Bi silicates was unveiled: tuning the electronic structure of Bi, weakening the Bi-O bond, and strengthening electron transfer from Bi to CO 2 , thereby promoting the generation of CO 2 * − and *OCHO intermediates. Additionally, carbon nanotubes (CNTs) promote not only the conductivity but also the generation of abundant oxygen vacancies in CNT@Bi silicates evidenced by the electron transfer from CNT to Bi silicates from XPS results. Further, the CNT@Bi silicates endows it with the highest electrochemical activation area. These findings suggest the effectiveness of Si in Bi silicates and structure tuning to design highly selective CO 2 RR catalyst for HCOOH production.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2024
·
IF 8.2
Siwei Guo,Huili Zeng,Xiaomin Zhu,Lin Liu,Baoliang Chen,Xin Xiao
Silicon within Si-rich biochars (sichar) plays a crucial role in immobilizing heavy metals and providing slow-releasing bioavailable silicon for silicophilic plants. However, the impact of heating rate on the silicon properties and carbon‑silicon interactions in sichars remains unclear. In this study, rice husk was used as a silicon-rich biomass to prepare sichars at different heating rates (10, 30 and 60 °C per minute, and ultra-fast-pyrolysis), then experiments such as silicon concentration measurement, Raman and XRD characterization were conducted. The results showed that a faster heating rate reduced the carbon content during pyrolysis while promoted the formation of amorphous silica, resulting in a threefold increase in dissolved silicon in sichars prepared at 400 °C. Additionally, we observed the formation of a meta-stable SiO 2 polymorph (tridymite) in rice husk-derived biochars under fast heating, differing from the previously observed quartz generated at slow heating rates. Regarding the C Si relationship, a faster heating rate facilitated the removal of the surface carbon layer, exposing the underlying silicon layer. This led to more soluble silicon species and less encapsulated silicon, resulting in a continuous release and cumulative silicon dissolution amount 1.2 times and 1.6–1.9 times higher, respectively, than those in slow heating rate-derived sichars. Consequently, this enhanced silicon uptake in rice seedlings. Our findings indicate that beyond pyrolysis temperature, the heating rate significantly affects the silicon species, silicon dissolution behavior, and carbon‑silicon relationships of biochar, ultimately determines the properties and applications of sichars.
研究领域:
植物学
·
环境科学
·
土壤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2024
·
IF 4.5
Yang Liu,Qi Lin,Xu Long,Shuting Zhang,Hong Dong,Yanjiang Song,Chuan Wu
Three kinds of α -triethylsiloxyl- ω -trimethoxysilyethyl-terminated oligomers (TES-PDMS-TMOS, TES-PTFPMS-TMOS, and TES-PDES-TMOS) were synthesized through an anion catalyzed non-equilibrium ring-opening polymerization reaction of cyclotrisiloxanes and subsequent hydrosilylation reaction with vinyltrimethoxysilane. As the in situ surface modification agent for mixed-size AlN inorganic fillers (1, 20 and 50 μm blended in a mass ratio of 3:5:9), these oligomers have been mixed with Vi-PDMS in a mass ratio of 1:2. Relative to that of silicone pastes using Vi-PDMS as the polymer matrix , the thermal conductivity of silicone pastes made from AlN particles treated with these oligomers is enhanced, while their thermal resistances decreased. With the change of the repeating unit structure in the oligomers, the silicone pastes prepared from these oligomer-treated AlN fillers differ significantly in filler content, thermal conductivity , and thermal resistance. When TES-PTFPMS-TMOS is used and filled with 800 parts (70.3 vol%) of hybrid AlN powders, a silicone paste with a thermal conductivity of 4.56 W/(m. K) could be achieved, which was 37.8% higher than that silicone paste using pure Vi-PDMS as the matrix. When TES-PDES-TMOS is used and filled with 900 parts (72.7 vol%) of hybrid AlN powders, the thermal conductivity of the silicone paste reaches 4.13 W/(m. K). Despite its thermal conductivity being only 3.5% higher relative to the silicone paste using only Vi-PDMS as the polymer matrix, its thermal resistance decreased by 20.3%. When TES-PDMS-TMOS is used and filled with 1200 parts (78.0 vol%) of hybrid AlN powders, the thermal conductivity of the silicone paste could reach up to 4.59 W/(m. K), together with a thermal resistance 29.6% lower than that of silicone paste where 1000 parts (74.7 vol%) of hybrid AlN particles filled in the Vi-PDMS. The heat dissipation of the 30 W high-brightness LED chip also illustrated the excellent thermal conductivities of these silicone pastes. The effect of another terminal group on the monotrimethoxysilylethyl-terminated asymmetric polysiloxanes on the thermal resistance of thermal interface materials was also discussed in detail.
研究领域:
材料科学
·
热管理技术
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Kemeng Liu,Xueying Wen,Huiyue Wang,Huajian Liu,Lijie Liu,Ran Niu,Tao Tang,Nan Yao,Ruikun Pan,Jiang Gong
Chemical recycling of silicone rubber (SR) waste into valuable products has aroused ever-increasing attention; however, the development of a green, efficient degradation strategy for silicone rubber remains challenging. In this work, we report the catalytic upcycling of silicone rubber by AlCl 3 to produce SiO 2 under atmospheric environment. The optimized AlCl 3 /SR mass ratio, reaction temperature and time are 0.75, 280 ℃ and 120 min, respectively. The maximum yield of SiO 2 is 96 %. The as-prepared SiO 2 displays irregular spherical agglomerates with a particle size of 20–30 nm and bears rich micropores/mesopores/macropores. The result of variable-temperature Fourier-transform infrared spectroscopy proves that AlCl 3 promotes the fracture of Si-O in SR during heating. According to density functional theory, the addition of AlCl 3 leads to a decrease in the bond dissociation energy of Si-O and Si-C. The strategy achieves the green, efficient catalytic degradation of silicone rubber waste.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2021
·Vol. 11
·期 7
·850
·
IF 2.881
Kaixin Fu,Yi Li,Xiumin Chen,Wenhui Ma,Ziheng Yang,Tong Wang,Jiasen Liu,Zhuang Ma,Ran Chen,Xiuhua Chen,Shaoyuan Li
In this study, amino group surface-functionalized porous silicon adsorbent was successfully prepared for the first time using diamond wire saw silicon powder (DWSSP) as raw material through copper-assisted chemical etching (Cu-ACE) and organic functional group grafting. Amino-functionalized porous silicon adsorbent (TEPA-GTS-NPSi) can be used for removing As(V) from water. The properties and mechanism of the new adsorbent were characterized by infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller analysis (BET), and thermogravimetric analysis (TGA). The concentration of metal ions in the solution was determined by inductively coupled plasma spectrometry. Meanwhile, the effects of initial pH, adsorption time, initial concentration and adsorbent dosage on the removal of As(V) in an aqueous solution were studied by intermittent adsorption experiments. The results showed that the adsorption equilibrium could be reached rapidly after 30 min soaking. Under the optimized pH of 7, the maximum adsorption capacity was 13.2 mg/g, and the minimum adsorption limit was 3 mg/L. The adsorbent shows good adsorption performance after five successive regenerated cycles. Based on the density functional theory (DFT) analysis results, the adsorption mechanism is attributed to hydrogen bond interaction between the NH2group and As(V) ions.Keywords:silicon cutting powder;copper-assisted chemical etching;surface modification;waste recycling;arsenic removal
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2016
·
IF 1.207
Fang Jin,Xianqiao Wang,Tieliang Liu,Linbo Xiao,Ming Yuan,Yangchun Fan
A new effective process to improve the utilization of industrial fluorosilicic acid of phosphate fertilizer by-product has been investigated to comprehensive application of the silicon and fluorine source. Two-step ammoniation was applied to recover high-quality silica. The recovered silica can be used to hydrothermal synthesize ZSM-5 zeolite without impurity phase contamination, which was confirmed by XRD, TG, SEM, BET and EDS characteristic techniques. It was found that with the increase of SiO 2 /Al 2 O 3 ratio and the extension of reaction time, the crystal type transform from the orthorhombic to the monoclinic phase. The impurity fluorine content of the recovered SiO 2 from H 2 SiF 6 has great influence on the hydrothermal process for ZSM-5 crystal structure formation. Moreover, the increase of fluorine ions content in the hydrothermal process can control the crystal morphology and size of synthesized ZSM-5. Catalytic properties of synthesized HZSM-5 with different SiO 2 /Al 2 O 3 ratio in transalkylation of toluene and 1,2,4-trimethylbenzene show good and stable catalytic performance. The ZSM-5 synthesized with recovered silica source exhibits similar catalyst life as the performance of small particle size HZSM-5, because the ZSM-5 synthesized with the silica source from industrial hexafluorosilicic acid prefers a thin disk crystal along the b axis direction, which shortens the diffusion distance of generated products.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Hao Xiong,Anze Shui,Qingliang Shan,Mei Cai,Xiuan Xi,Bin Du
The SiO 2 layer preferentially generated on the surface of silicon carbide abrasives in Polishing Porcelain stoneware tile Residues (PPR) is corroded by silicate liquid during firing, resulting in continuous oxidation and foaming of silicon carbide, which makes the PPR difficult to be reused. The PPR is fired to form a silicate liquid that wraps micron silicon carbide in it. In this work, it is possible to study the corrosion of silicate to silicon carbide at high temperature by using two ( Ceramic-SiC ) and three ( Ceramic-SiO 2 -SiC ) layer structure model to simulate the corrosion of silicate to silicon carbide. The corrosion mechanism of SiC in PPR by silicate liquid during firing is revealed that the corrosion rate at its two sides (interfaces) determines the ultimate change in the thickness of the corrosion layer between the ceramic and the SiO 2 layer. Importantly, the corrosion layer thickness with time on the silicate-SiO 2 cross-section periodically presents wave-like changes, which can be attributed to the ionic migration between layers and the rate at which cations cross the corrosion layer when studying the three-layer model.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
PHYCOLOGICAL RESEARCH
·
2017
·Vol. 65
·期 3
·177-187
·
IF 1.338
Xiao-li Li,Thomas Kiran Marella,Ling Tao,Rong Li,Archana Tiwari,Gu Li
SUMMARY Diatoms are a group of highly abundant and diverse aquatic algae species. They contain high lipid content along with many bioactive compounds that can be exploited for biotechnological applications. Despite these attractive attributes, diatoms are underrepresented in production projects due to difficulties in their cultivation. To optimize the growth of three freshwater diatom isolates, Cyclotella sp., Synedra sp. and Navicula sp., an orthogonal assay on N, P, Si and Fe, as well as temperature and pH, was designed using traditional single-factor tests. We also studied the effect of using nanosilica as an alternate Si source on growth and found that the diatom isolates studied achieved their highest growth rates under different combinations of nutrient and environmental conditions. Silica had the greatest influence on growth, followed by phosphate and iron. The optimized growth conditions for Synedra sp. were N: 30 mg L −1 , P: 3 mg L −1 , Si: 14.8 mg L −1 , Fe: 0.448 mg L −1 , temperature 25°C and pH 8. For Navicula sp.: N: 20 mg L −1 , P: 2.5 mg L −1 , Si: 19.7 mg L −1 , Fe: 0.112 mg L −1 , temperature 30°C and pH 7.5–8. For Cyclotella sp.: N: 20 mg L −1 , P: 2.5 mg L −1 , Si: 19.7 mg L −1 , Fe: 0.448 mg L −1 , temperature 30°C and pH 7.5–8. Nano silica negatively affected growth in Navicula sp. and Cyclotella sp., but no such effect was observed in Synedra sp. Fatty acid profiling showed C16:0, C16:1( n − 7), C18:0 and C20:5( n − 3) as major fatty acids, with no significant differences in fatty acid methyl ester profiles between traditional and modified media. This work gives us a new insight into the growth requirements of freshwater diatom species, which are less studied than marine species.
研究领域:
生物技术
·
环境科学
·
藻类学
✓ 已验证
产品关联
DOI
高影响因子
AATCC Journal of Research
·
2022
·
IF 0.726
Shiwei Li,Heng Quan,Li Ai,Shuguang Bi,Qing Li,Renchuan You
Superhydrophobic textiles have attracted great interest due to their special functions and wide applications. However, it is still a huge challenge to construct a durable superhydrophobic coating for large-scale applications due to the complicated process and high cost. In this work, a facile two-step method was developed to construct superhydrophobic cotton fabric with fluorine-free treatment. The cotton fabrics were treated with modified nano SiO2 to construct rough surfaces. Then, the silicone oil was introduced into the surface of the cotton fabric to form superhydrophobic cotton fabric. The results showed that the modified nano SiO2 and silicone oil were stably fixed on the fiber surface. The static water contact angle test showed that contact angle of the modified cotton fabric was 158°, indicating excellent superhydrophobic properties. Furthermore, the self-cleaning and anti-pollution test results showed that the superhydrophobic cotton fabric possessed good self-cleaning and antifouling performance. This superhydrophobic fabric avoids the use of fluoropolymers and reduces the harm to humans and environment, showing a wide range of applications.
研究领域:
材料科学
·
纺织工程
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 6
·1137
·
IF 5.3
Zhiqiang Tang,Yanxia Liu,Yagang Zhang,Zicai Sun,Weidong Huang,Zhikai Chen,Xiaoli Jiang,Lin Zhao
In the field of flexible electronics manufacturing, inkjet printing technology is a research hotspot, and it is key to developing low-temperature curing conductive inks that meet printing requirements and have suitable functions. Herein, methylphenylamino silicon oil (N75) and epoxy-modified silicon oil (SE35) were successfully synthesized through functional silicon monomers, and they were used to prepare silicone resin 1030H with nano SiO2. 1030H silicone resin was used as the resin binder for silver conductive ink. The silver conductive ink we prepared with 1030H has good dispersion performance with a particle size of 50–100 nm, as well as good storage stability and excellent adhesion. Additionally, the printing performance and conductivity of the silver conductive ink prepared with n,n-dimethylformamide (DMF): proprylene glycol monomethyl ether (PM) (1:1) as solvent are better than those of the silver conductive ink prepared by DMF and PM solvent. Cured at a low temperature of 160 °C, the resistivity of 1030H-Ag-82%-3 conductive ink is 6.87 × 10−6Ω·m, and that of 1030H-Ag-92%-3 conductive ink is 0.564 × 10−6Ω·m, so the low-temperature curing silver conductive ink has high conductivity. The low-temperature curing silver conductive ink we prepared meets the printing requirements and has potential for practical applications.Keywords:functional silicon monomers;silicone resin;low-temperature curing;silver conductive inks
研究领域:
材料科学
·
柔性电子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）