Synthesis of superhydrophobic silica nanofibrous membranes with robust thermal stability and flexibility via in situ polymerization

Nanoscale ◽  
2012 ◽  
Vol 4 (20) ◽  
pp. 6581 ◽  
Author(s):  
Liping Yang ◽  
Aikifa Raza ◽  
Yang Si ◽  
Xue Mao ◽  
Yanwei Shang ◽  
...  
RSC Advances ◽  
2016 ◽  
Vol 6 (113) ◽  
pp. 112429-112434 ◽  
Author(s):  
Hao Zhang ◽  
Young-Kwon Moon ◽  
Xue-Quan Zhang ◽  
He-Xin Zhang ◽  
Keun-Byoung Yoon

The in situ polymerization approach proposed here will open a new and exciting avenue for the development of transition metal dichalcogenide reinforced polyethylene nanocomposites.


2012 ◽  
Vol 502 ◽  
pp. 31-35 ◽  
Author(s):  
Xiao Hua Wang

Polyaniline(PANI) with the doping of hydrochloride(HC1), aminosulfonic acid (NH2SO3H) or dodecylbenzenesulfonic acid(DBSA) was prepared by in-situ polymerization. Effects of acid content, reaction time, oxidant ammonium persulfate (APS) dosage and reaction temperature on the conductivity of PANI were studied. The resistance and thermal stability of them were compared. Results show that the largest conductivity of HC1-PANI is 1.98 s.cm-1 among them in case the C(HC1)=0.5mol/L, reaction time is 6.0h, n(APS/aniline)=1.0; The conductivity of NH2SO3H-PANI is 0.2s.cm-1 in case the C(NH2SO3H)=1.0mol/L, reaction time is 6.0h, n(APS/aniline)=2.0; The conductivity of DBSA-PANI is 0.98s.cm-1 in case the C(DBSA)=1.0 mol/L, reaction time is 8.0h, n(APS/aniline) = 2.0. The the least resistance of HC1-PANI is 10Ω, and that of NH2SO3H- PANI is the largest of 120Ω. The order of their thermal stability is DBSA-PANI > NH2SO3H-PANI > HC1-PANI before 350°C, that of their thermal stability is inverse when it reaches 350°C.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1651 ◽  
Author(s):  
Saisai Huang ◽  
Qiufang Jiang ◽  
Bin Yu ◽  
Yujing Nie ◽  
Zhongqing Ma ◽  
...  

Acetylation and in situ polymerization are two typical chemical modifications that are used to improve the dimensional stability of bamboo. In this work, the combination of chemical modification of vinyl acetate (VA) acetylation and methyl methacrylate (MMA) in situ polymerization of bamboo was employed. Performances of the treated bamboo were evaluated in terms of dimensional stability, wettability, thermal stability, chemical structure, and dynamic mechanical properties. Results show that the performances (dimensional stability, thermal stability, and wettability) of bamboo that was prepared via the combined pretreatment of VA and MMA (VA/MMA-B) were better than those of raw bamboo, VA single-treated bamboo (VA-B), and MMA single-treated bamboo (MMA-B). According to scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analyses, VA and MMA were mainly grafted onto the surface of the cell wall or in the bamboo cell lumen. The antiswelling efficiency and contact angle of VA/MMA-B increased to maximum values of 40.71% and 107.1°, respectively. From thermogravimetric analysis (TG/DTG curves), the highest onset decomposition temperature (277 °C) was observed in VA/MMA-B. From DMA analysis, the storage modulus (E’) of VA/MMA-B increased sharply from 15,057 Pa (untreated bamboo) to 17,909 Pa (single-treated bamboo), and the glass transition temperature was improved from 180 °C (raw bamboo) to 205 °C (single-treated bamboo).


2019 ◽  
Vol 14 ◽  
pp. 155892501982744 ◽  
Author(s):  
Juan Xie ◽  
Wei Pan ◽  
Zheng Guo ◽  
Shan Shan Jiao ◽  
Ling Ping Yang

Polypyrrole/cotton composites have substantial application potential in flexible heating devices due to their flexibility, high conductivity, and thermal stability. In this context, a series of flexible polypyrrole/cotton fabrics were intrinsically prepared using in situ polymerization process with the different Py/FeCl3 concentration ratios. To investigate their structural and morphological properties, thermal stability, tensile strength, conductivity, and heat-generating property, the composite fabrics were subjected to Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, thermo-gravimetric analysis, mechanical properties, and resistivity measurements. The results showed that polypyrrole/cotton fabrics exhibited a low resistivity of 0.37 Ω cm. Temperature–time curve showed that temperature of the polypyrrole/cotton fabrics increased very quickly from room temperature to a steady-state maximum temperature of 168.3°C within 3 min at applied voltage of 5 V. Tensile strength of polypyrrole/cotton composites reached to 58 MPa, which far surpassed raw cotton fabrics. Therefore, polypyrrole/cotton fabrics have exhibited high electrical, thermal properties, and mechanical strength, which can be utilized as an ideal flexible heating element.


2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
Valentina Sabatini ◽  
Hermes Farina ◽  
Luca Basilissi ◽  
Giuseppe Di Silvestro ◽  
Marco A. Ortenzi

Polylactic acid (PLA) nanocomposites were prepared via “in situ” ring opening polymerization (ROP) of lactide using a montmorillonite, Cloisite 15A, employed after surface treatment with 3-Glycidoxypropyltrimethoxysilane. The dispersion of the nanoparticles was checked using Wide Angle X-Ray Scattering (WAXS) and Transmission Electron Microscopy (TEM); both the effects of different amounts of montmorillonite and silane were measured on molecular weights and on thermal and rheological properties, using Size Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), thermogravimetric analyses (TGA), and rheological analyses. It was found that even very low amounts (0.1% w/w) of nanoparticles greatly affect nanocomposites properties. Unmodified montmorillonite tends to decrease molecular weights, deactivating the catalytic system used for ROP of lactide, but when epoxy silane is present molecular weights increase. Melt crystallization temperatures increase with modified nanoparticles, which enhance crystallization process. TGA analyses show that when pure montmorillonite is present, nanocomposites have lower thermal stability with respect to standard PLA; when silane is used thermal stability can get much higher than standard PLA as silane content increases. The rheological behaviour of nanocomposites shows that melt viscosity is far higher than that of standard PLA at low shear rates and also a marked shear thinning behaviour can be achieved.


2011 ◽  
Vol 233-235 ◽  
pp. 1830-1833 ◽  
Author(s):  
Yong Chen ◽  
Hui Xu ◽  
Tao Sun

The PMMA/TiO2 nanocomposites were prepared by in situ polymerization,the dissolution, thermal stability and the mechanical property of the nanocomposites were studied. The results indicated that nano-TiO2 may be crosslinking points in the matrix and the thermal stability of the nanocomposites became higher. As the content of nano-TiO2 increased, the mechanical properties of the nanocomposites had great changes.


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