BRIGHT LUMINESCENCE OF FIRE RETARDANT ALUMINUM HYDROXIDE-SILICA SPHERE COMPOSITE

2018 ◽  
Vol 25 (06) ◽  
pp. 1850113
Author(s):  
HA-SUNG KONG ◽  
BYOUNG-JU KIM ◽  
KWANG-SUN KANG

Bright luminescence was achieved with excess amount of aluminum hydroxide with silica spheres. Various amounts of aluminum hydroxide were attached to silica spheres to improve the performance of fire retardancy. Although silica spheres attached with 60[Formula: see text]wt.% of AlCl3 (AlOH-A) showed no color change and luminescent chromophores, silica spheres attached with 80[Formula: see text]wt.% of (AlOH-B) and 100% of (AlOH-C) of AlCl3 changed the color and produced luminescent chromophores. The solution colors became intense yellow and brown for AlOH-B and AlOH-C, respectively, after 15 days. The FTIR spectra showed the characteristic absorption peaks of Al–OH and Si–O–Al. The concentration dependent photoluminescence (PL) intensities were continuously increased until 242[Formula: see text]mg addition of the colored solution and then slightly decreased thereafter for both AlOH-B and AlOH-C. The PL peaks shifted toward red by increasing the excitation wavelength for both AlOH-B and AlOH-C. Large Stoke shifts, such as 73 and 68[Formula: see text]nm for AlOH-B and AlOH-C, respectively, were observed.

2018 ◽  
Vol 64 (3) ◽  
pp. 105-114 ◽  
Author(s):  
Masayuki Kawarasaki ◽  
Ryoichi Hiradate ◽  
Yasushi Hirabayashi ◽  
Shinichi Kikuchi ◽  
Yoshifumi Ohmiya ◽  
...  

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 91 ◽  
Author(s):  
Natalia E. Markina ◽  
Alexey V. Markin

This report is dedicated to development of surface-enhanced Raman spectroscopy (SERS) based analysis protocol for detection of antibiotics in urine. The key step of the protocol is the pretreatment of urine before the detection to minimize background signal. The pretreatment includes extraction of intrinsic urine components using aluminum hydroxide gel (AHG) and further pH adjusting of the purified sample. The protocol was tested by detection of a single antibiotic in artificially spiked samples of real urine. Five antibiotics of cephalosporin class (cefazolin, cefoperazone, cefotaxime, ceftriaxone, and cefuroxime) were used for testing. SERS measurements were performed using a portable Raman spectrometer with 638 nm excitation wavelength and silver nanoparticles as SERS substrate. The calibration curves of four antibiotics (cefuroxime is the exception) cover the concentrations required for detection in patient’s urine during therapy (25/100‒500 μg/mL). Random error of the analysis (RSD < 20%) and limits of quantification (20‒90 μg/mL) for these antibiotics demonstrate the applicability of the protocol for reliable quantitative detection during therapeutic drug monitoring. The detection of cefuroxime using the protocol is not sensitive enough, allowing only for qualitative detection. Additionally, time stability and batch-to-batch reproducibility of AHG were studied and negative influence of the pretreatment protocol and its limitations were estimated and discussed.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 955 ◽  
Author(s):  
Demiao Chu ◽  
Jun Mu ◽  
Stavros Avramidis ◽  
Sohrab Rahimi ◽  
Shengquan Liu ◽  
...  

To enhance compression stability and fire retardancy of densified wood, a new modification method i.e., combined nitrogen–phosphorus (NP) fire retardant pre-impregnation with surface thermo-mechanical densification is used to fabricate a certain thickness of functionalized surface layer on poplar. This combined treated wood is investigated via vertical density profile (VDP), and the compression stability is revealed by both soaking test and cone analysis. Results demonstrate that the combined treatment hardened the surface of wood and reformed the interface combination of the NP with the wood cell wall, thus making the surface tissue more close-grained. Fire retardancy was also enhanced; the total heat release and CO generation values decreased by 21.9% and 68.4%, respectively, when compared with that of solely NP-treated wood. Moreover, surface hardness increased by 15.8%, and the recovery of surface hardness and thickness were 56.8% and 77.2% lower than that of simply densified wood. It appears that this NP-involved thermal densification could be considered as an alternative approach to enhance both the compression stability and fire resistance of wood.


2019 ◽  
Vol 34 (1) ◽  
pp. 96-106 ◽  
Author(s):  
Chao Zheng ◽  
Dongfang Li ◽  
Monica Ek

Abstract Sustainable thermal insulating materials produced from cellulosic fibers provide a viable alternative to plastic insulation foams. Industrially available, abundant, and inexpensive mechanical pulp fiber and recycled textile fiber provide potential raw materials to produce thermal insulating materials. To improve the fire retardancy of low-density thermal insulating materials produced from recycled cotton denim and mechanical pulp fibers, bio-based fire retardants, such as sulfonated kraft lignin, kraft lignin, and nanoclays, were coated onto sustainable insulating material surfaces to enhance their fire retardancy. Microfibrillated cellulose was used as a bio-based binder in the coating formula to disperse and bond the fire-retardant particles to the underlying thermal insulating materials. The flammability of the coated thermal insulating materials was tested using a single-flame source test and cone calorimetry. The results showed that sulfonated kraft lignin-coated cellulosic thermal insulating materials had a better fire retardancy compared with that for kraft lignin with a coating weight of 0.8 kg/m2. Nanoclay-coated samples had the best fire retardancy and did not ignite under a heat flux of 25 kW/m2, as shown by cone calorimetry and single-flame source tests, respectively. These cost-efficient and bio-based fire retardants have broad applications for improving fire retardancy of sustainable thermal insulating materials.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2554 ◽  
Author(s):  
Zhi Geng ◽  
Shuaishuai Yang ◽  
Lianwang Zhang ◽  
Zhenzhen Huang ◽  
Qichao Pan ◽  
...  

Introducing fire-retardant additives or building blocks into resins is a widely adopted method used for improving the fire retardancy of epoxy composites. However, the increase in viscosity and the presence of insoluble additives accompanied by resin modification remain challenges for resin transfer molding (RTM) processing. We developed a robust approach for fabricating self-extinguishing RTM composites using unmodified and flammable resins. To avoid the effects on resin fluidity and processing, we loaded the flame retardant into tackifiers instead of resins. We found that the halogen-free flame retardant, a microencapsulated red phosphorus (MRP) additive, was enriched on fabric surfaces, which endowed the composites with excellent fire retardancy. The composites showed a 79.2% increase in the limiting oxygen index, a 29.2% reduction in heat release during combustion, and could self-extinguish within two seconds after ignition. Almost no effect on the mechanical properties was observed. This approach is simple, inexpensive, and basically applicable to all resins for fabricating RTM composites. This approach adapts insoluble flame retardants to RTM processing. We envision that this approach could be extended to load other functions (radar absorbing, conductivity, etc.) into RTM composites, broadening the application of RTM processing in the field of advanced functional materials.


2014 ◽  
Vol 33 (22) ◽  
pp. 2021-2033 ◽  
Author(s):  
Ahmad Bilal ◽  
Richard JT Lin ◽  
Krishnan Jayaraman

A parametric study on the flammability characteristics of rice husk-reinforced polyethylene composites with various material compositions was conducted to find the “best” composites’ formulation for fire retardancy. Composites were manufactured using rice husk, maleated anhydride polyethylene and linear medium density polyethylene. The blends for manufacturing of composites were selected using mixture design approach. The individual effects of each constituent material on the fire performance of composites by cone calorimeter were studied using trace and contour plots for the various thermal and flammability properties. Regression coefficients were also estimated for each measured response. The cone calorimetry results show that the addition of rice husk improved fire retardancy of composites. The addition of maleated anhydride polyethylene did not influence the flammability properties much, except for mass loss rate and specific extinction area. The optimum mixture of rice husk, maleated anhydride polyethylene and linear medium density polyethylene for overall “best” flammability properties of the composites was also determined by multiple response optimisation using the regression models in Design Expert software. The optimum mixture for overall “best” fire retardant properties was found to be 50 wt% of rice husk, 5.6 wt% of maleated anhydride polyethylene and 44.4 wt% of linear medium density polyethylene. The flammability properties measured from composites manufactured with this formulation closely matched the values predicted by the model.


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