Surface Modification of Bacterial Cellulose Sheets With Various Fire Retardants

Author(s):  
Eser Sözen ◽  
Gökhan Gündüz ◽  
Deniz Aydemir ◽  
Ahmet Can

Abstract This study investigated the effects of various fire retardants including Firetex®, phosphoric acid, and nanoboron nitride on the thermal and morphological properties of bacterial cellulose (BC) sheets. Hestrin and Schramm medium was inoculated with Gluconacetobacter hansenii and the medium with the bacteria was incubated for 14 days. The obtained BC sheets were freeze-dried and then the dried sheets were immersed with Firetex®, phosohoric acid, and nanoboron nitride for a day. The sheets were once again freeze-dried and weight percent gain (WPG) of the sheets was calculated by using wet and dried weights. The morphological characterization, thermal properties, and structural changes of the obtained sheets were also investigated with scanning electron microscopy (SEM), thermogravimetric analysis, and Fourier-transform infrared spectroscopy, respectively. The weight percent gain was found to increase 31% for the samples with boron nitride and 1040% for the samples with phosphoric acid after the impregnation. The thermogravimetric analysis showed that the impregnation improved the thermal stability of the BC films. The sheets with nanoboron nitride exhibited the best thermal stability, whereas the sheets with Firetex were determined to have the worst thermal stability. The Fourier-transform infrared spectroscopy showed some changes in the structural properties of the all BC sheets with fire retardants. As a result, it can be said that nanoboron nitride at low temperatures (25–250 °C) and Firetex and phosphoric acid at higher temperatures (600–900 °C) showed better thermal stability.

2016 ◽  
Vol 47 (6) ◽  
pp. 993-1005 ◽  
Author(s):  
Yasemin Cakmak ◽  
M Fatih Canbolat ◽  
Enes Cakmak ◽  
Mehmet Dayik

The aim of this study was to produce advanced nanofiber mats by adding boron nitride to poly (ɛ-caprolactone) polymer using an electrospinning method and to characterize the resultant structures. Pure poly (ɛ-caprolactone) nanofiber mats and boron nitride-doped nanofiber mats prepared at different concentrations were compared. The morphological structures of the nanofiber mats were examined under a scanning electron microscope, spectroscopic analyses were conducted using Fourier transform infrared spectroscopy, and thermal stability was analyzed using a thermogravimetric analysis method. Successful electrospinning of boron nitride-doped nanofibers at lower voltages was achieved. The thermogravimetric analysis test found that the thermal stability of boron nitride-doped nanofiber mats is higher than that of pure nanofibers, which suggests that the produced composite material could be preferable in applications involving insulation and high temperature. On the other hand, the Fourier transform infrared spectroscopy results indicated that no chemical reaction occurred between boron nitride and the poly (ɛ-caprolactone) nanofibers.


2020 ◽  
Vol 70 (4) ◽  
pp. 387-395
Author(s):  
Qi Li ◽  
Xiaosheng Liu ◽  
Huidong Su ◽  
An Mao ◽  
Hui Wan

Abstract In this study, we compare the panel performance of plywood made with phenol-formaldehyde (PF) resins modified and blended with phenol-rich bio-oil produced from pyrolysis of biomass. The modified PF resins were synthesized with phenol-rich bio-oil at phenol substitutions of 10, 25, 50, and 75 percent. The blended PF resins were prepared by blending control PF resin with phenol-rich bio-oil at 4, 13, 23, and 38 percent by weight. These resins were examined with Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) and evaluated as plywood binders. The results indicated that the apparent viscosities of modified PF resins were similar to those of control PF resin, while the apparent viscosities of blended PF resins increased with the addition of phenol-rich bio-oil. As the amount of phenol-rich bio-oil increased, the gel times of both modified and blended PF resins decreased first and then increased. FTIR results showed that modified PF resins with up to 25 percent substitution had FTIR spectra similar to those of control PF resin, while blended PF resins with a higher amount of added bio-oil had spectra more like those of bio-oil. TGA results showed that at temperatures of 25°C to 400°C, both modified and blended PF resins with high bio-oil content had better thermal stability than the control PF resin. Panel tests showed that modifying or synthesizing PF resin with phenol-rich bio-oil up to 50 percent increased both dry and wet bond strength. Blending PF resin with phenol-rich bio-oil up to 13 percent increased both dry and wet bond strength compared with control PF resin.


2014 ◽  
Vol 1048 ◽  
pp. 423-426
Author(s):  
Huan Yang Yu

Polystyrene beads modified with ester group for the separation of n-heptane/toluene have been successfully prepared. The synthesized beads were characterized by fourier transform infrared spectroscopy and thermogravimetric analysis. The effects of ester group on equillibrium swelling ratio and toluene selectivity were studied. The selective factor firstly increases then decreases with the increasing of ester group content. When the content of ester group is 30%, selective factor reaches maximum, the value is 1.62. Polystyrene beads modified with ester group show excellent thermal stability.


Molbank ◽  
10.3390/m1101 ◽  
2019 ◽  
Vol 2020 (1) ◽  
pp. M1101
Author(s):  
Richa Mardianingrum ◽  
Susanti ◽  
Ruswanto Ruswanto

The bis(N′-(3-chlorobenzoyl)isonicotinohydrazide)iron(III) complex was synthesised from N′-(3-chlorobenzoyl)isonicotinohydrazide and iron(III) metal by reflux in an ethanol solution. The title compound was characterised by Fourier-transform infrared spectroscopy (FTIR) spectroscopy, differential thermal analysis/thermogravimetric analysis (DTA/TGA) and UV-visible spectroscopy. The results indicate that coordination of the iron(III) ion to the ligand increased its thermal stability.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dejia Liu ◽  
Sükrü Caliskan ◽  
Bita Rashidfarokhi ◽  
Harriëtte Oldenhof ◽  
Klaus Jung ◽  
...  

AbstractFreeze-drying can be used to ensure off-the-shelf availability of decellularized heart valves for cardiovascular surgery. In this study, decellularized porcine aortic heart valves were analyzed by nitroblue tetrazolium (NBT) staining and Fourier transform infrared spectroscopy (FTIR) to identify oxidative damage during freeze-drying and subsequent storage as well as after treatment with H2O2 and FeCl3. NBT staining revealed that sucrose at a concentration of at least 40% (w/v) is needed to prevent oxidative damage during freeze-drying. Dried specimens that were stored at 4 °C depict little to no oxidative damage during storage for up to 2 months. FTIR analysis shows that fresh control, freeze-dried and stored heart valve specimens cannot be distinguished from one another, whereas H2O2- and FeCl3-treated samples could be distinguished in some tissue section. A feed forward artificial neural network model could accurately classify H2O2 and FeCl3 treated samples. However, fresh control, freeze-dried and stored samples could not be distinguished from one another, which implies that these groups are very similar in terms of their biomolecular fingerprints. Taken together, we conclude that sucrose can minimize oxidative damage caused by freeze-drying, and that subsequent dried storage has little effects on the overall biochemical composition of heart valve scaffolds.


2021 ◽  
Vol 287 ◽  
pp. 02014
Author(s):  
Amin Abbasi ◽  
Mohamed Mahmoud Nasef ◽  
Wan Zaireen Nisa Yahya ◽  
Muhammad Moniruzzaman

The conversion of palm oil into a sulfur-based polymer by copolymerization with sulfur powder at its molten state is herein reported. The obtained sulfur-containing polymer was characterized using Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to demonstrate the successful conversion. The disappearance of the peaks related to vinylic groups of oil together with the appearance of a peak representing C-H rocking vibrations in the vicinity of C-S bonds confirmed the copolymerization of sulfur with oil. TGA revealed that the polymers have thermal stability up to 230°C under nitrogen and the polymers leave 10% sulfur-rich ash. DSC proved that a small amount of elemental sulfur remained unreacted in the polymer, which showed amorphous and heavily crosslinked structure resembling thermosets. These copolymers are an environmental-friendly polymeric material promoting the utilization of the abundant sulfur while also adding value to palm oil.


2014 ◽  
Vol 881-883 ◽  
pp. 297-301 ◽  
Author(s):  
Yan Zhi Liu ◽  
Shun Ping Wang ◽  
Kun Yuan ◽  
Huian Tang

The solid acid catalyst (ACSA) for the gutter oil esterification to biodiesel was prepared via active carbon as raw material by introducing the-SO3H group onto the surface of it. The ACSA were characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and elemental analysis (EA), respectively. And the results showed that the-SO3H groups were successfully introduced onto the surface of the active carbon and the containing of the-SO3H groups are higher than 0.017g per gram of ACSA.


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