scholarly journals An Effective, Economical and Ultra-Fast Method for Hydrophobic Modification of NCC Using Poly(Methylhydrogen)Siloxane

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 963
Author(s):  
Xueqing You ◽  
Qingjian Hu ◽  
Xiaoyong Hu ◽  
Hanxian Chen ◽  
Wenbin Yang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Weight Ratio ◽  
Hydroxyl Groups ◽  
Fast Method ◽  
Hydrophobic Modification ◽  
X Ray Diffraction ◽  
Water Contact ◽  
X Ray ◽  
Low Surface Energy ◽  
Thermal Stability Of

Poor compatibility between nanocellulose crystals (NCCs) and major polymers has limited the application of NCC as bio-reinforcements. In this work, an effective and ultra-fast method was investigated to significantly improve the hydrophobicity of NCC by using poly(methylhydrogen)siloxane (PMHS) as modifier. PMHS possessed amounts of reactive –Si–H groups and hydrophobic –CH3 groups. The former groups were reactive with the hydroxyl groups of NCC, while the latter groups afforded NCC very low surface energy. As the weight ratio of PMHS to NCC was only 0.0005%, the hydrophobicity of NCC was significantly improved by increasing the water contact angle of NCC from 0° to 134°. The effect of weight ratio of PMHS to NCC and the hydrogen content of –Si–H in PMHS on the hydrophobicity and thermal stability was investigated in detail by Fourier transform infrared spectroscopy (FTIR), (X-ray Diffraction) XRD and (thermogravimetric analysis) TGA. The results indicated that PMHS chains were covalently grafted onto NCC and PMHS modification improved the thermal stability of NCC.

scholarly journals SINTESIS DAN KARAKTERISASI FAUJASIT DARI ABU LAYANG : Kajian Pengaruh Waktu Sintesis Terhadap Stabilitas Termal Struktur Faujasit (Kinetics of Faujasite Formation from Fly Ash)

2019 ◽  
Vol 2 (2) ◽  
pp. 10
Author(s):  
Sutarno Sutarno ◽  
Arief Budyantoro
Keyword(s):  
Thermal Stability ◽  
Fly Ash ◽  
Amorphous Phase ◽  
Zeolite Y ◽  
Weight Ratio ◽  
Hydrothermal Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of ◽  
Thermal Stability Of

Faujasite was hydrothermally synthesized from fly ash at 100oC in alkaline solution by reflux with 5M HCl and fusion with NaOH (weight ratio of NaOH/fly ash = 1.2) pretreatments. Kinetics of faujasite formation was performed by variation of hydrothermal time (0-120 hours). Thermal stability of faujasite from fly ash was tested at 400-900oC and was compared with commercial zeolite Y. The solid products were characterized by X-ray diffraction method. Results showed that faujasite was formed through dissolution of fly ash components such as quartz, mullite and amorphous aluminosilicates (0-3 hours) followed by crystallization to form faujasite (6-48 hours). In longer hydrothermal time (48-72 hours), faujasite transformed into zeolite P and completely formed hydroxysodalite after 120 hours. X-ray diffraction pattern showed that thermal stability of faujasite from fly ash was relatively lower than that of commercial zeolite Y. Faujasite from fly ash transformed into amorphous phase at 800oC whereas commercial zeolite Y transformed into amorphous phase at 900oC.

scholarly journals Facile Preparation of Biocomposite from Prawn Shell Derived Chitosan and Kaolinite-Rich Locally Available Clay

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Shanta Biswas ◽  
Taslim U. Rashid ◽  
Abul K. Mallik ◽  
Md. Minhajul Islam ◽  
M. Nuruzzaman Khan ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Weight Ratio ◽  
Alkaline Media ◽  
X Ray Diffraction ◽  
Kaolinite Clay ◽  
X Ray ◽  
Fourier Transformed Infrared Spectroscopy ◽  
The Matrix ◽  
Acidic And Alkaline Media ◽  
Thermal Stability Of

A novel composite material was prepared from prawn shell derived chitosan (CHT) and locally available kaolinite-rich modified Bijoypur clay (MC) using a facile technique in which dilute acetic acid was used as a solvent for dissolving chitosan and composite fabrication whereas distilled water was used for preparing the clay dispersion. Bijoypur clay mainly consists of kaolinite clay mineral and it was modified with the dodecyl amine to make it organophilic. Morphology and properties of the composites (different weight ratio of MC and CHT) have been studied and compared with those of pure CHT and MC. Purification and modification of Bijoypur clay were investigated by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transformed infrared spectroscopy (FTIR) analyses. The fabrication of CHT-MC composites was confirmed by FTIR analysis. Thermogravimetric analysis (TGA) and differential scanning colorimetry (DSC) were used to investigate the thermal stability of the composites. It was observed that dispersed clay improves the thermal stability and enhances the hardness of the matrix systematically with the increase of clay loading. In this study, a better insolubility in both acidic and alkaline media of the composites is also observed compared to pure chitosan.

scholarly journals Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2254
Author(s):  
Adeleke A. Oyekanmi ◽  
N. I. Saharudin ◽  
Che Mohamad Hazwan ◽  
Abdul Khalil H. P. S. ◽  
Niyi G. Olaiya ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Coupling Agent ◽  
Silane Coupling Agent ◽  
Cellulose Nanofibrils ◽  
Hydroxyl Groups ◽  
Water Contact ◽  
Silane Coupling ◽  
Cnf Films ◽  
Kenaf Bast ◽  
Thermal Stability Of

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

Formation and Thermal Stability of Nd0.32Y0.68Si1.7 Layers Formed by Channeled Ion Beam Synthesis

1998 ◽  
Vol 514 ◽  
Author(s):  
M. F. Wu ◽  
A. Vantomne ◽  
S. Hogg ◽  
H. Pattyn ◽  
G. Langouche ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Ion Beam ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Good Crystalline Quality ◽  
Ion Beam Synthesis ◽  
Thermal Stability Of

ABSTRACTThe Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

Study of Thermal Behaviour of EPDM/SBR Blends and Carbon Nanocoatings Deposited by Sputtering

2021 ◽  
Vol 875 ◽  
pp. 116-120
Author(s):  
Muhammad Alamgir ◽  
Faizan Ali Ghauri ◽  
Waheed Qamar Khan ◽  
Sajawal Rasheed ◽  
Muhammad Sarfraz Nawaz ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
Thermogravimetric Analysis ◽  
Thermal Behavior ◽  
Thermal Behaviour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

In this study, the effect of SBR concentration (10 Phr, 20 Phr & 30 Phr ) on the thermal behavior of EPDM/SBR blends was studied. Thermogravimetric analysis (TGA) was used to check weight loss of samples as function of temperature by heating upto 600°C. X-ray diffraction (XRD) was performed to determine quality and % crystallinity of the elastomer blends. It was seen that % crystallinity improved with an increase in the content of SBR in EPDM/SBR blends. TGA revealed that the thermal stability of EPDM/SBR blends has improved by 17% than neat EPDM. Carbon nano-coatings produced by sputtering have no beneficial influence on thermal behaviour of elastomers.

Syntheses, Crystal Structures and Thermal Stability of Co(II) and Zn(II) Complexes with Ethyl Carbazate

2005 ◽  
Vol 60 (5) ◽  
pp. 505-510 ◽  
Author(s):  
Tong-Lai Zhang ◽  
Jiang-Chuang Song ◽  
Jian-Guo Zhang ◽  
Gui-Xia Ma ◽  
Kai-Bei Yu
Keyword(s):  
Thermal Stability ◽  
Aqueous Solutions ◽  
Diffraction Analysis ◽  
Single Crystals ◽  
Slow Evaporation ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
Thermal Stabilities ◽  
X Ray ◽  
Thermal Stability Of

Cobalt(II) and zinc(II) complexes of ethyl carbazate (ECZ), [Co(ECZ)3](NO3)2 and [Zn(ECZ)3] (NO3)2, were synthesized. Single crystals of these two compounds were grown from aqueous solutions using a slow evaporation method. Their structures have been determined by X-ray diffraction analysis. Both of them are monoclinic with space group P21/n. The complexes are further characterized by element analysis and IR measurements. Their thermal stabilities are studied by using TG-DTG, DSC techniques. When heated to 350 °C, only metal oxide was left for both complexes.

Immobilization of hemoglobin on stable mesoporous multilamellar silica vesicles and their activity and stability

2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi
Keyword(s):  
Thermal Stability ◽  
Pore Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Silica Material ◽  
Transmission Electron ◽  
Mesoporous Support ◽  
Adsorption Desorption ◽  
Thermal Stability Of

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.

Thermal stability of Mg3Sb1.475Bi0.475Te0.05 high performance n-type thermoelectric investigated through powder X-ray diffraction and pair distribution function analysis

2018 ◽  
Vol 6 (35) ◽  
pp. 17171-17176 ◽  
Author(s):  
Lasse Rabøl Jørgensen ◽  
Jiawei Zhang ◽  
Christian Bonar Zeuthen ◽  
Bo Brummerstedt Iversen
Keyword(s):  
Thermal Stability ◽  
Distribution Function ◽  
Pair Distribution Function ◽  
High Performance ◽  
Function Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

The thermal stability of the high performance n-type Te-doped Mg3Sb1.5Bi0.5 system is investigated.

scholarly journals Exploring the Complexation of Counterion in Novel Family of Polyelectrolytes with Unexpected Solubility Behaviour

2020 ◽  
Vol 869 ◽  
pp. 61-68
Author(s):  
Egor A. Bersenev ◽  
Alina Maryasevskaya ◽  
Evgenii V. Komov ◽  
Denis V. Anokhin ◽  
Dimitri A. Ivanov
Keyword(s):  
Thermal Stability ◽  
Ir Spectroscopy ◽  
Lithium Salt ◽  
Ionic Form ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkali Ions ◽  
In Series ◽  
Chelating Complex ◽  
Thermal Stability Of

In the present paper we study the effect of complexation in linear negatively charged polyelectrolytes with different alkali ions. With combination of IR-spectroscopy, X-ray diffraction and nanocalorimetry, we attempted to explain unusual solubility, crystallinity and thermal stability of these polymers. The increase of thermal stability and insolubility in water in series of semi-crystalline polysalts as K+ ≤ H+ <Na+ was explained by effectiveness of formation of chelating complex. Insoluble in water sodium salt shows the highest thermal stability of crystal phase up to . In contrast, well soluble in water amorphous lithium salt does not self-organize in chelating complex and is presented in ionic form.

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