scholarly journals Thermogravimetric, Devolatilization Rate, and Differential Scanning Calorimetry Analyses of Biomass of Tropical Plantation Species of Costa Rica Torrefied at Different Temperatures and Times

Energies ◽  
2018 ◽  
Vol 11 (4) ◽  
pp. 696 ◽  
Author(s):  
Johanna Gaitán-Álvarez ◽  
Róger Moya ◽  
Allen Puente-Urbina ◽  
Ana Rodriguez-Zúñiga
Keyword(s):  
Differential Scanning Calorimetry ◽  
Costa Rica ◽  
Scanning Calorimetry ◽  
Plantation Species ◽  
Different Temperatures ◽  
Tropical Plantation

scholarly journals Swelling properties of chitosan hydrogels

2004 ◽  
Vol 22 (1) ◽  
pp. 32 ◽  
Author(s):  
David R Rohindra ◽  
Ashveen V Nand ◽  
Jagjit R Khurma
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Glass Transition ◽  
Free Water ◽  
Scanning Calorimetry ◽  
Swelling Behaviour ◽  
Swelling Properties ◽  
Different Temperatures ◽  
Ft Ir ◽  
Chitosan Hydrogels

Chitosan hydrogels were prepared by crosslinking chitosan with glutaraldehyde. The swelling behaviour of the crosslinked and uncross-linked hydrogels was measured by swelling the gels in media of different pH and at different temperatures. The swelling behavior was observed to be dependent on pH, temperature and the degree of crosslinking. The gel films were characterized by Fourier transform Infrared spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) and the amount of free water in the hydrogels decreased with increasing crosslinking in the hydrogels.

GROWTH AND STUDIES OF PROPERTIES OF COPPER SUCCINATE DIHYDRATE SINGLE CRYSTALS

2013 ◽  
Vol 27 (11) ◽  
pp. 1350073
Author(s):  
M. P. BINITHA ◽  
P. P. PRADYUMNAN
Keyword(s):  
Differential Scanning Calorimetry ◽  
Dielectric Constant ◽  
Single Crystals ◽  
Scanning Calorimetry ◽  
Force Microscopy ◽  
Atomic Force ◽  
Different Temperatures ◽  
Triclinic Structure ◽  
Ft Ir ◽  
Ft Ir Spectroscopy

Single crystals of copper succinate dihydrate (CSD) with triclinic structure were grown in silica gel medium. The functional groups in the crystal were analyzed by FT-IR Spectroscopy. Atomic Force Microscopy (AFM) revealed the striations on the surface of grown crystals, which were incorporated during its time of growth. Thermal degradation studies have been carried out by Differential Scanning Calorimetry (DSC). Dielectric constant and AC conductivity have been estimated as a function of frequency at different temperatures.

Study on the Precipitation Sequence of Aged NCu30-4-2-1 Alloy by DSC

2014 ◽  
Vol 1061-1062 ◽  
pp. 35-38
Author(s):  
Yun Long Ai ◽  
Xiao Rui Shen ◽  
Wei Hua Chen ◽  
Yao Hui Xie
Keyword(s):  
Solid Solution ◽  
Differential Scanning Calorimetry ◽  
Supersaturated Solid Solution ◽  
Aging Treatment ◽  
Holding Time ◽  
Precipitation Sequence ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Different Temperatures ◽  
Block Distribution

NCu30-4-2-1 alloy was handled by solid solution at 950°Cfor 2h and then taking aging treatment at different temperatures and holding time. The microstructural evolution of NCu30-4-2-1 alloy in the process of aging treatment was investigated by metallographic microscope, X-ray diffractometer and differential scanning calorimetry. The results show that the phases of as-cast NCu30-4-2-1 alloy is composed by dendritic α-Ni-based solid solution and β-Ni3Si. After solid solution and aging treatment, the block distribution β-Ni3Si dissolves and many small granular dispersed distribution β'-Ni3Si precipitate out. With the increase of aging temperature and holding time, metastable β' tends to transform into stable β-Ni3Si. The precipitation sequence of aged NCu30-4-2-1alloy is supersaturated solid solution of α-Ni, GP zone, β'-Ni3Si and β-Ni3Si.

Synthesis, characterization and separation properties of novel PU membranes crosslinked by β-cyclodextrin

2013 ◽  
Vol 33 (3) ◽  
pp. 285-292 ◽  
Author(s):  
Hong Ye ◽  
Jing Wang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Soft Segment ◽  
Chain Extender ◽  
Scanning Calorimetry ◽  
Structures And Properties ◽  
Separation Factors ◽  
Different Temperatures ◽  
Ft Ir ◽  
A Chain ◽  
Phenol Water

Abstract Polyurethane (PU) pervaporation (PV) membranes are promising for the recovery of phenol from water. The four kinds of PU membranes, with hydroxyl terminated polybutadiene (HTPB) as a soft segment and diamine or β-cyclodextrin (CD) as a chain extender, were prepared. The structures and properties of these membranes were characterized by means of Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and contact angle. Furthermore, the PV performances were investigated for separating phenol/water mixtures at different temperatures. The results showed that CD increased the permeability and selectivity of PU, at the same time. At 80°C, the total fluxes of pure PU membranes with HTPB (Mn=2500 g/mol) (H2500) and with HTPB (Mn=2000 g/mol) (H2000) were 6.96 kg μm m-2 h-1 and 6.09 kg μm m-2 h-1, respectively, while those of PU membranes containing CD with HTPB (Mn=2500 g/mol) (H2500-CD) and with HTPB (Mn=2000 g/mol) (H2000-CD) were 9.16 kg μm m-2 h-1 (increased by 31%) and 8.23 kg μm m-2 h-1 (increased by 26%), respectively. The separation factors of H2500 and H2000 were 23 and 34, while those of H2500-CD and H2000-CD were 33 (increased by 43%) and 40 (increased by 9%). Additionally, the modification of CD crosslinking was simple and easy with less modifying agent.

scholarly journals Formamidinium iodide: crystal structure and phase transitions

2017 ◽  
Vol 73 (4) ◽  
pp. 569-572 ◽  
Author(s):  
Andrey A. Petrov ◽  
Eugene A. Goodilin ◽  
Alexey B. Tarasov ◽  
Vladimir A. Lazarenko ◽  
Pavel V. Dorovatovskii ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transitions ◽  
Powder Diffraction ◽  
Solid Phase ◽  
Monoclinic Space Group ◽  
Scanning Calorimetry ◽  
Polymorphic Modifications ◽  
Different Temperatures ◽  
Physicochemical Methods ◽  
Hydrogen Bonded

At a temperature of 100 K, CH5N2+·I−(I), crystallizes in the monoclinic space groupP21/c. The formamidinium cation adopts a planar symmetrical structure [the r.m.s. deviation is 0.002 Å, and the C—N bond lengths are 1.301 (7) and 1.309 (8) Å]. The iodide anion does not lie within the cation plane, but deviates from it by 0.643 (10) Å. The cation and anion ofIform a tight ionic pair by a strong N—H...I hydrogen bond. In the crystal ofI, the tight ionic pairs form hydrogen-bonded zigzag-like chains propagating toward [20-1]viastrong N—H...I hydrogen bonds. The hydrogen-bonded chains are further packed in stacks along [100]. The thermal behaviour ofIwas studied by different physicochemical methods (thermogravimetry, differential scanning calorimetry and powder diffraction). Differential scanning calorimetry revealed three narrow endothermic peaks at 346, 387 and 525 K, and one broad endothermic peak at ∼605 K. The first and second peaks are related to solid–solid phase transitions, while the third and fourth peaks are attributed to the melting and decomposition ofI. The enthalpies of the phase transitions at 346 and 387 K are estimated as 2.60 and 2.75 kJ mol−1, respectively. The X-ray powder diffraction data collected at different temperatures indicate the existence ofIas the monoclinic (100–346 K), orthorhombic (346–387 K) and cubic (387–525 K) polymorphic modifications.

scholarly journals Extraction and Characterization of Galactan from Seaweed Gracilaria verrucosa of Vietnam 

2021 ◽  
Vol 31 (1) ◽  
pp. 73-77
Keyword(s):  
Differential Scanning Calorimetry ◽  
Infrared Spectroscopy ◽  
Thermal Resistance ◽  
Gracilaria Verrucosa ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Kjeldahl Method ◽  
Viscosity Determination

In this study, we extracted galactan from the seaweed Gracilaria verrucosa of Vietnam and investigated its structure and properties. The seaweed was immersed in water in the different temperatures to obtain the solution of galactan. Thereafter, the solution was coagulated and purified to obtain galactan as a powder. Kjeldahl method, infrared spectroscopy, viscosity determination and differential scanning calorimetry (DSC) were used to characterize structure and properties of the resulting material. It was found that the obtained galactan had agar structure without sulfate as substitute group. The proteins content, the intrinsic viscosity and the thermal resistance of the galactan extracted in water at 40 oC were higher than those of the galactan extracted in water at 100 oC.

scholarly journals Physical Ageing of Amorphous Indapamide Characterised by Differential Scanning Calorimetry

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 800
Author(s):  
Agata Drogoń ◽  
Marcin Skotnicki ◽  
Agnieszka Skotnicka ◽  
Marek Pyda
Keyword(s):  
Differential Scanning Calorimetry ◽  
Glass Transition ◽  
Amorphous State ◽  
Modulated Dsc ◽  
Physical Ageing ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Fragility Parameter ◽  
Liquid States

The objective of this study was to characterise amorphous indapamide (IND) subjected to the physical ageing process by differential scanning calorimetry (DSC). The amorphous indapamide was annealed at different temperatures below the glass transition, i.e., 35, 40, 45, 65, 75 and 85 °C for different lengths of time, from 30 min up to a maximum of 32 h. DSC was used to characterise both the crystalline and the freshly prepared glass and to monitor the extent of relaxation at temperatures below the glass transition (Tg). No ageing occurred at 35, 40 and 45 °C at the measured lengths of times. Molecular relaxation time constants (τKWW) for samples aged at 65, 75 and 85 °C were determined by the Kohlrausch-Williams-Watts (KWW) equation. The fragility parameter m (a measure of the stability below the glass transition) was determined from the Tg dependence from the cooling and heating rates, and IND was found to be relatively stable (“moderately fragile”) in the amorphous state. Temperature-modulated DSC was used to separate reversing and nonreversing processes for unaged amorphous IND. The enthalpy relaxation peak was clearly observed as a part of the nonreversing signal. Heat capacities data for unaged and physically aged IND were fitted to Cp baselines of solid and liquid states of IND, were integrated and enthalpy was presented as a function of temperature.

Characterization of Spin on Glass Using Thermo Analytical Techniques and Ftir Spectroscopy

1990 ◽  
Vol 204 ◽  
Author(s):  
M. Speciale ◽  
C. La Rosa ◽  
D. Grasso ◽  
A. Porto ◽  
P. Lanza ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Ftir Spectroscopy ◽  
Analytical Techniques ◽  
Experimental Results ◽  
Thermal Treatments ◽  
Cross Polarization ◽  
Scanning Calorimetry ◽  
Thermoanalytical Techniques ◽  
Different Temperatures

ABSTRACTThe curing of a commercial ethoxymethyl-phosphosiloxane at different temperatures and under various gas ambients was characterised using NMR, thermoanalytical techniques, and FTIR spectroscopy. DSC (Differential Scanning Calorimetry) and DTG (Differential Thermo Gravimetry) were employed to characterize the reactions that occur during thermal treatments in O2 or N2 atmospheres. FTIR spectroscopy and CP (Cross Polarization) 133C - NMR were used to detect the presence of the hydroxyl and organic groups in the cured samples. The experimental results identified three different temperatures (400,580,700°C) that define important stages of the curing reaction. In particular, for annealing at temperatuires up to 580°C in 02, DSC, DTG and FTIR spectra showed the elimination of the organic groups. However, when the annealing was carried out in N2 up to 700°C, these groups are retained.

scholarly journals Implications of Global and Local Mobility in Amorphous Excipients as Determined by DSC and TM DSC

2009 ◽  
Vol 4 (2) ◽  
pp. 105-115
Author(s):  
Ion Dranca ◽  
Tudor Lupascu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Differential Scanning Calorimeter ◽  
Scanning Calorimetry ◽  
Modulated Differential Scanning Calorimetry ◽  
The Real ◽  
Local Mobility ◽  
Complex Heat Capacity ◽  
Different Temperatures ◽  
Global And Local

The paper explores the use of differential scanning calorimetry (DSC) and temperature modulated differential scanning calorimetry (TM DSC) to study α- and β- processes in amorphous sucrose and trehalose. The real part of the complex heat capacity is evaluated at the frequencies, f, from 5 to 20mHz. β-relaxations were studied by annealing glassy samples at different temperatures and subsequently heating at different rates in a differential scanning calorimeter.

The structural modification of epoxy resins by a liquid elastomer

1994 ◽  
Vol 6 (1) ◽  
pp. 71-81
Author(s):  
A Padma ◽  
R M V G K Rao ◽  
C Subramaniam
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Reaction Mechanism ◽  
Acrylic Acid ◽  
Epoxy Resins ◽  
Structural Modification ◽  
Scanning Calorimetry ◽  
Different Temperatures ◽  
Group Reaction ◽  
Diaminodiphenyl Methane

A carboxy terminated poly-n-(butyl acrylate, acrylic acid, acrylonitryl) (PNBA) terpolymer was used as a modifier for three high-functionality epoxy resins, (i) epoxy novolac, (ii) triglycidyl-4-aminophenol (TGPAP) and (iii) tetraglycidyl diaminodiphenyl methane (TGDDM), used as matrix materials in polymer composites. The resin and elastomer were reacted using different amine catalysts at different temperatures. The progress of the reaction between the epoxy resin and elastomer was studied extensively by Fourier transform infrared (FMR) spectroscopy and differential scanning calorimetry (psc). The results show that hydroxy esterification and etherification occurred during the epoxy-carboxy group reaction. The possible reaction mechanism involved is discussed on the basis of the results obtained.

Sign in / Sign up

Export Citation Format

Share Document