scholarly journals Impact of Layer-by-Layer Self-Assembly Clay-Based Nanocoating on Flame Retardant Properties of Sisal Fiber Cellulose Microcrystals

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Chun Wei ◽  
Sihua Zeng ◽  
Yuyuan Tan ◽  
Wu Wang ◽  
Jian Lv ◽  
...  

The renewable cationic polyelectrolyte chitosan (CH) and anionic nanomontmorillonite (MMT) layers were alternately deposited on the surface of sisal fiber cellulose microcrystals (SFCM) via layer-by-layer (LBL) self-assembly method. The structure and properties of the composites were characterized by zeta potential, thermal gravimetric analysis (TGA), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometer (FTIR), microcalorimeter (MCC), and so forth. The zeta potential results show that the cellulose microcrystalline surface charge reversed due to the adsorption of CH and MMT nanoplatelets during multilayer deposition. MMT characteristic diffraction peaks appear in XRD patterns of SFCM(CH/MMT)5and SFCM(CH/MMT)10composites. Additionally, FESEM reveals that the SFCM(CH/MMT)10surface is covered with a layer of material containing Si, which has been verified by elemental analysis. TGA results show that the initial decomposition (weight loss of 5%) temperature of SFCM(CH/MMT)5is increased by 4°C compared to that of pure SFCM. On the other hand, carbon residue percentage of SFCM(CH/MMT)10is 25.1%, higher than that of pure SFCM (5.4%) by 19.7%. Eventually, it is testified by MCC measurement that CH/MMT coating can significantly reinforce the flame retardant performance of SFCM.

Cellulose ◽  
2019 ◽  
Vol 26 (4) ◽  
pp. 2729-2741
Author(s):  
Chenmin Zheng ◽  
Sili Wen ◽  
Ziling Teng ◽  
Chunlu Ye ◽  
Qiaoling Chen ◽  
...  

Author(s):  
Jun Hu ◽  
Zuoguo Yang

Abstract Unlike previous utilization of ultrafiltration membranes as supporters of graphene oxide (GO) composite membranes, this study first adopts microporous nylon membranes as substrates. The cationic polyelectrolyte/GO composite membranes are prepared by the layer-by-layer self-assembly method via electrostatic attraction. The introduction of polycations between nanochannels in the GO membranes effectively suppresses the swelling and improves the stability of the membranes. It is found that the polyelectrolytes' charge density and the surface potential of the composite membranes jointly determine the membranes' properties. The experimental results show that the novel GO membranes can obtain high flux and considerable desalination performance under low operating pressure. Typically, the salt rejection rate reaches 66.8% for 1.0 g/L MgSO4, and the flux is 39.8 L·m−2·h−1·bar−1. Benefitting from the GO composite membranes keeping similar retention for both high and low concentration salt solutions, the ideal desalination performance could be obtained through multi-stage processes on the premise of ensuring high flux, which is more suitable for industry.


2008 ◽  
Vol 8 (6) ◽  
pp. 2996-3002 ◽  
Author(s):  
Liqin Ge ◽  
Xing Wang ◽  
Long Ba ◽  
Zhongze Gu

The hydrogen-bonding multilayered polyelectrolyte capsules with sizes around 6 μm were fabricated by layer-by-layer self-assembly method. The morphology of the obtained capsules was observed with Scanning Electron Microscope (SEM), Confocal Laser Scanning Microscope (CLSM) and Atomic Force Microscope (AFM), respectively. The elastic properties of the capsules were studied with AFM. The capsule was pressed by cantilever with different lengths, a glass bead glued at the end of the cantilever. The force curves were measured on the capsule in air. The Young's modulus of the capsule was obtained (E = 170 MPa for the loading). Results show that this model can predict the elastic deformation of the microcapsule. The accuracy of the elastic deformation of polymer capsule can be ensured using a cantilever of mediate stiffness. Our results show that the existence of the hydrogen-bonding layer makes the multilayered polyelectrolyte harder in comparison with the pure multilayered polyelectrolyte capsules.


RSC Advances ◽  
2016 ◽  
Vol 6 (59) ◽  
pp. 53625-53634 ◽  
Author(s):  
Ying Pan ◽  
Wei Wang ◽  
Haifeng Pan ◽  
Jing Zhan ◽  
Yuan Hu

Montmorillonite and titanate nanotube based coatings have been prepared through LbL self-assembly method, in order to enhance the thermal and thermal-oxidative stability, flame retardancy and UV protection of polyethylene terephthalate fabric.


2021 ◽  
Author(s):  
Pundalik Mali ◽  
Narendra Sonawane ◽  
Nilesh Pawar ◽  
Vikas Patil

Abstract A novel melamine-phosphate trifunctional acrylate MPTO) was successfully synthesized via simple cyclization of hexamethylolmelamine (HMM) with phosphorous oxychloride (POCl3) followed by addition reaction of hydroxyethylmethacrylate (HEMA). The molecular structure of MPTO was identified by FTIR and 1H-NMR, 13C-NMR, and GC-MS spectra. The synthesized MPTO oligomer was impregnated with polyurethane acrylate to make the various formulation of UV-cured coatings. The polyurethanes-MPTO oligomers were coated on wood and galvanized steel panels. The properties of UV-cured PU-MPTO were studied by differential scanning calorimeter (DSC), while their crystallinity by X-ray diffraction analysis (XRD). The thermo-gravimetric analysis (TGA) exhibited a high char yield of 18.4% at 800 °C. Moreover, coating films show prominent flame retardancy with UL-94 V-0 rating and maximum limiting index value (LOI) values of 34.8%, which are much higher than the common polyurethane coatings. The polyurethane coatings cured with MPTO exhibited excellent mechanical properties were estimated various tests such as adhesion, pencil hardness, solvent resistance, flexibility, and corrosion test. The coating performance revealed that MPTO improves the mechanical, thermal, and flame retardant properties because their unique structure contains melamine-phosphate moiety and long aliphatic chains of an acrylate ester. These high-performance melamine-based UV-curable coatings are promising for extensive applications.


2021 ◽  
Author(s):  
Xinhua Liu ◽  
Hailong Liu ◽  
Yinchun Fang

Abstract In this study, intumescent flame retardant coating of polyethylenimine/phytic acid (PEI/PA) with gradient structure was constructed on cotton fabric through facile layer-by-layer (LBL) assembly method. The LOI value of coated cotton fabric reached over 40% indicating excellent flame retardancy. Reasonable controlling the LBL assembly process of PEI/PA coating brought less influence to the physical properties of cotton fabrics. And the coated cotton fabric revealed good flame retardant washing durability. Thermogravimetric analysis results of coated cotton fabrics showed that PEI/PA flame retardant coating changed the thermal decomposition process and promoted char formation revealing the obviously condensed phase flame retardant action. SEM images of char residues revealed that PEI/PA flame retardant coating promoted to form the intumescent flame retardant (IFR) char layer showing obvious IFR action. This research provides novel strategy for the development of high-efficiency flame retardant cotton fabric with good durability and physical properties using simple LBL assembly method.


2017 ◽  
Vol 5 (31) ◽  
pp. 7746-7752 ◽  
Author(s):  
Xueliang Ye ◽  
Zhen Yuan ◽  
Huiling Tai ◽  
Weizhi Li ◽  
Xiaosong Du ◽  
...  

A novel strain sensor based on reduced graphene oxide with ultra-sensitive and ultra-durable performance was fabricated by the chemical layer-by-layer self-assembly method.


2020 ◽  
Vol 134 ◽  
pp. 140-148 ◽  
Author(s):  
Eduarda Freitas Diogo Januário ◽  
Natália de Camargo Lima Beluci ◽  
Taynara Basso Vidovix ◽  
Marcelo Fernandes Vieira ◽  
Rosângela Bergamasco ◽  
...  

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