Thermally Stable Polyimide/Silica Hybrid: Synthesis, Characterization and Optical Nonlinearity

2010 ◽  
Vol 123-125 ◽  
pp. 1275-1278
Author(s):  
Guang Yu Wu ◽  
Cheng Yao ◽  
Feng Xian Qiu
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Nonlinear Optical ◽  
Sol Gel ◽  
Optical Nonlinearity ◽  
29Si Nmr ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Electro Optic

An intercalation nonlinear-optical (NLO) polyimide was synthesized based on the 3,3’, 4,4’- Bisphenyltetracarboxylic (BPDA) and [(6-nitrobenzothiazole-2-yl)diazenyl]phenyl-1,3- diamine (NBADA). Then, hybrid polymer was synthesized by the sol-gel technique. FT-IR spectroscopy and 29Si NMR were used to characterize the structure of the hybrid. The results revealed that Q3, Q4 and T3 are the major microstructure elements in forming a network structure. The surface morphology, particle size, crystallinity and the thermal stability of the hybrid were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). DSC and TGA results showed that the glass transition temperature (Tg) and the decomposition temperature (Td) at 5% mass loss were 243, 359°C and 355, 456°C, respectively. These results showed that the hybrid material had excellent thermal stability than the pure polyimide. The electro-optic coefficients of nonlinear optical polyimide and hybrid were measured at the wavelength of 832 nm. The electro-optic coefficients were 22 and 19pm/V (poling voltage of 3.8KV, 210°C) and the values remained well (retained＞93% for more than 100h). The results suggest that the materials have potential applications for high performance optical device.

scholarly journals Curing Kinetics and Thermal Stability of Epoxy Composites Containing Newly Obtained Nano-Scale Aluminum Hypophosphite (AlPO2)

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 644 ◽  
Author(s):  
Farimah Tikhani ◽  
Shahab Moghari ◽  
Maryam Jouyandeh ◽  
Fouad Laoutid ◽  
Henri Vahabi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
High Performance ◽  
Frequency Factor ◽  
Curing Temperature ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Nano Scale ◽  
Aluminum Hypophosphite ◽  
Thermal Stability Of

For the first time, nano-scale aluminum hypophosphite (AlPO2) was simply obtained in a two-step milling process and applied in preparation of epoxy nanocomposites varying concentration (0.1, 0.3, and 0.5 wt.% based on resin weight). Studying the cure kinetics and thermal stability of these nanocomposites would pave the way toward the design of high-performance nanocomposites for special applications. Scanning electron microscopy (SEM) and transmittance electron microscopy (TEM) revealed AlPO2 particles having domains less than 60 nm with high potential for agglomeration. Excellent (at heating rate of 5 °C/min) and Good (at heating rates of 10, 15 and 20 °C/min) cure states were detected for nanocomposites under nonisothermal differential scanning calorimetry (DSC). While the dimensionless curing temperature interval (ΔT*) was almost equal for epoxy/AlPO2 nanocomposites, dimensionless heat release (ΔH*) changed by densification of polymeric network. Quantitative cure analysis based on isoconversional Friedman and Kissinger methods gave rise to the kinetic parameters such as activation energy and the order of reaction as well as frequency factor. Variation of glass transition temperature (Tg) was monitored to explain the molecular interaction in the system, where Tg increased from 73.2 °C for neat epoxy to just 79.5 °C for the system containing 0.1 wt.% AlPO2. Moreover, thermogravimetric analysis (TGA) showed that nanocomposites were thermally stable.

Janus molecules: large second-order nonlinear optical performance, good temporal stability, excellent thermal stability and spherical structure with optimized dendrimer structure

2018 ◽  
Vol 2 (7) ◽  
pp. 1374-1382 ◽  
Author(s):  
Pengyu Chen ◽  
Huanyu Zhang ◽  
Mengmeng Han ◽  
Ziyao Cheng ◽  
Qian Peng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nonlinear Optical ◽  
Temporal Stability ◽  
Second Order ◽  
Optical Performance ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Spherical Structure ◽  
Electro Optic

A Janus molecule J2 containing five FTC moieties exhibited good thermal stability, excellent electro-optic performance and good temporal stability.

scholarly journals Graphitic Carbon Nitride based Photocatalytic Systems for High Performance Hydrogen Production: A Review

2021 ◽  
pp. 161-192
Author(s):  
S. Sharma
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Ion Exchange ◽  
Distribution Coefficient ◽  
High Performance ◽  
Sol Gel ◽  
Exchange Capacity ◽  
Ion Exchange Capacity ◽  
E Coli ◽  
Scanning Electron

Pectin cerium(IV) iodate (PcCeI) and cerium(IV) iodate (CeI) cation ion exchange materials were synthesized via sol–gel methods. The materials were characterized by using Fourier transform infrared spectroscopy, X-ray diffractometer, thermogravimetric analysis, and scanning electron microscopy. The ion exchange capacity (IEC), thermal stability, distribution coefficient (Kd), and pH titrations were investigated to recognize the cation exchange behavior of the materials. The IEC of pectin-cerium(IV) iodate (PcCeI and cerium(IV) iodate CeI were reported as 1.80 meq/g and 0.92 meq/g, respectively. The higher distribution coefficient values of 250.01 and 219.14 mg/L confirmed the selectivity of pectin-cerium(IV) iodate hybrid ion exchanger for As3+ and Zn2+. The antibacterial activity of synthesized ion exchangers was explored for E. coli bacteria and observed relatively higher for PcCeI as compared to CeI.

SYNTHESIS AND ELECTRO-OPTIC PROPERTY OF INTERCALATION POLYIMIDE AND NANOHYBRID

2008 ◽  
Vol 17 (04) ◽  
pp. 443-450
Author(s):  
D. Y. YANG ◽  
F. X. QIU ◽  
G. R. CAO
Keyword(s):  
Hybrid Material ◽  
High Performance ◽  
Sol Gel ◽  
Polymer Networks ◽  
Optical Devices ◽  
Excellent Thermal Stability ◽  
Electro Optic ◽  
Optic Property ◽  
Gel Technique ◽  
Electro Optic Property

Intercalation nonlinear-optical (NLO) polyimide and polyimide/silica hybrid material were synthesized by the sol–gel technique. The results showed that the interpenetrating hybrid polymer networks were formed and showed excellent thermal stability. The electro-optic property suggests that this hybrid material has potential for applications in high performance optical devices.

Eu3+/Tb3+ Co-Doped Cerium Oxide Transparent Nanocomposite for Color-Tunable Emission

NANO ◽  
2018 ◽  
Vol 13 (10) ◽  
pp. 1850119
Author(s):  
Xiaoyan Li ◽  
Yunlong Yu ◽  
Xiangfeng Guan ◽  
Peihui Luo ◽  
Linqin Jiang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Sol Gel ◽  
Homogeneous Precipitation ◽  
Transmission Electron ◽  
Color Tunable ◽  
Co Doped ◽  
Tunable Emission

Eu[Formula: see text]/Tb[Formula: see text] co-doped nanocomposite containing CeO2 nanocrystals was successfully prepared by an in situ sol–gel polymerization approach. High-resolution transmission electron microscopy demonstrated the homogeneous precipitation of CeO2 nanocrystals among the polymethylmethacrylate (PMMA) matrix. The thermal stability and UV-shielding capability of the obtained nanocomposite were improved with increase of CeO2 content. The tuning of the emissive color from green and yellow to red can be easily achieved by varying the dopant species and concentration. These results suggested that the obtained nanocomposite could be potentially applicable in transparent solid-state luminescent devices.

Pressure-controlled synthesis of high-performance SrLiAl3N4:Eu2+ narrow-band red phosphors

2018 ◽  
Vol 6 (38) ◽  
pp. 10174-10178 ◽  
Author(s):  
Mu-Huai Fang ◽  
Yi-Ting Tsai ◽  
Hwo-Shuenn Sheu ◽  
Jyh-Fu Lee ◽  
Ru-Shi Liu
Keyword(s):  
Thermal Stability ◽  
High Performance ◽  
Narrow Band ◽  
Controlled Synthesis ◽  
Excellent Thermal Stability ◽  
Red Phosphors ◽  
Pressure Controlled ◽  
Emission Bandwidth ◽  
Narrow Emission

SrLiAl3N4:Eu2+ (SLA) phosphors have gained increasing attention worldwide due to their narrow emission bandwidth and excellent thermal stability.

scholarly journals Ionic Liquids-Containing Silica Microcapsules: A Potential Tunable Platform for Shaping-Up Epoxy-Based Composite Materials?

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 881
Author(s):  
Ting Shi ◽  
Sébastien Livi ◽  
Jannick Duchet ◽  
Jean-François Gérard
Keyword(s):  
Electron Microscopy ◽  
Sol Gel ◽  
Diameter Distribution ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Micron Size ◽  
Phosphonium Ionic Liquid ◽  
One Step ◽  
The One ◽  
First Time

In this work, silica microcapsules containing phosphonium ionic liquid (IL), denoted SiO2@IL, were successfully synthesized for the first time using the one step sol-gel method in IL/H20 emulsion. The morphologies of the obtained micron-size microcapsules, including their diameter distribution, were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal behavior of these microcapsules and the mass fraction of the encapsulated IL in the silica microcapsules were determined using thermogravimetric analysis, showing an excellent thermal stability (up to 220 °C) and highlighting that an amount of 20 wt.% of IL is contained in the silica microcapsules. In a second step, SiO2@IL microcapsules (1 wt.%) were dispersed into epoxy-amine networks to provide proof of concept of the ability of such microcapsules to act as healing agents as microcracks propagate into the epoxy networks.

Synthesis of nonlinear optical chromophores with isophorone-derived bridges for enhanced thermal stability and electro-optic activity

2020 ◽  
Vol 8 (27) ◽  
pp. 9226-9235 ◽  
Author(s):  
Fenggang Liu ◽  
Songmin Mo ◽  
Zhaofen Zhai ◽  
Meishan Peng ◽  
Shuangke Wu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nonlinear Optical ◽  
Electro Optic ◽  
Nonlinear Optical Chromophores ◽  
Optical Chromophores

In this work, we developed a series of nonlinear optical chromophores J1–J4 with the same julolidinyl-based donor and tricyanovinyldihydrofuran acceptor with different modified isophorone-derived bridges.

Thermal and rheological properties of polyamide 6/layered double hydroxide clay composites

2019 ◽  
Vol 27 (9) ◽  
pp. 567-581 ◽  
Author(s):  
RDS Zwane ◽  
ER Sadiku ◽  
SS Ray ◽  
NE Luruli
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Rheological Properties ◽  
Layered Double Hydroxide ◽  
Polyamide 6 ◽  
Negative Influence ◽  
Scanning Calorimetry ◽  
Dynamic Mechanical ◽  
Double Hydroxide ◽  
Nucleating Effect

Thermal and rheological properties of polyamide 6/layered double hydroxide (PA6/LDH) composites were studied. Pristine (U-LDH) and organically modified (M-LDH) clays were used in this study. Some evidence of intercalation was observed on the microstructure of PA6/M-LDH samples, while PA6/U-LDH was characterised by microcomposite morphology as shown by the transmission electron microscopy results. The scanning electron microscopy results showed a complete delamination of the M-LDH in the PA6 matrix while U-LDH was evenly dispersed as immiscible tactoids. In the melt state, the M-LDH had a significant influence on the melt microstructure of PA6 matrix when compared to U-LDH. Differential scanning calorimetry results, both dynamic and isothermal experiments, showed that LDH had a heterogeneous nucleating effect on the PA6 matrix, with the U-LDH showing better nucleating effect when compared to M-LDH. The thermogravimetric analysis results showed that M-LDH had a negative influence on the thermal stability of the composites, while U-LDH improved their thermal stability. The X-ray diffraction and dynamic mechanical analysis results showed that the presence of M-LDH promoted the formation of γ-crystallites in the PA6 matrix, while U-LDH composites were dominated by the α-crystallites. This phenomenon had a positive correlation with increasing content of both LDH clays. An overall improved dynamic mechanical properties were observed for PA6/U-LDH when compared to PA6/M-LDH composites.

Sign in / Sign up

Export Citation Format

Share Document