scholarly journals Multiblock Elastomers TPEAA and TPEEA: Physical Structure and Properties

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7720
Author(s):  
Joanna Rokicka ◽  
Katarzyna Wilpiszewska ◽  
Jolanta Janik ◽  
Beata Schmidt ◽  
Anton Nikiforov ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Physical Structure ◽  
Chemical Compositions ◽  
Structure And Properties ◽  
Scanning Calorimetry ◽  
Soft Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Weight Content ◽  
Ft Ir

A three series of terpolymers composed of the blocks PTMO (MPTMO = 1000 g/mol) or DLAol (MDLAol = 540 g/mol), PA12 (MPA12 = 2000 g/mol) and xGT (DPxGT = 2) with various chemical compositions of ester block were obtained. The series differ in the chemical structure of the flexible block and weight content of the soft phase. The effect of the number of carbons dividing the terephthalate groups on the synthesis, structure and properties of these elastomers has been investigated. To confirm assumed chemical structure Carbon-13 (13C NMR) and Proton (1H NMR) Nuclear Magnetic Resonance and Fourier-transform Infrared Spectroscopy (FT-IR) were used. The influence of chemical compositions of ester block on the thermal properties and the phase separation of obtained systems were defined by Differential Scanning Calorimetry (DSC), Dynamic Mechanical Thermal Analysis (DMTA) and Wide Angle X-ray Scattering (WAXS). The mechanical and elastic properties were evaluated.

Thermotropic behavior of sodium cholesteryl carbonate

2009 ◽  
Vol 24 (1) ◽  
pp. 156-163 ◽  
Author(s):  
Rabkwan Chuealee ◽  
Timothy S. Wiedmann ◽  
Teerapol Srichana
Keyword(s):  
Phase Behavior ◽  
Chemical Structure ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Wave Number ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
C Nmr

Sodium cholesteryl carbonate ester (SCC) was synthesized, and its phase behavior was studied. The chemical structure was assessed by solid-state infrared spectroscopy based on vibration analysis. The wave number at 1705 and 1276 cm−1 corresponds to a carbonyl carbonate and O–C–O stretching of SCC, respectively. Molecular structure of SCC was further investigated with 1H and 13C NMR spectroscopy. The chemical shift, for the carbonyl carbonate resonance appeared at 155.5 ppm. A molecular mass of SCC was at m/z of 452. Differential scanning calorimetry (DSC), video-enhanced microscopy (VEM) together with polarized light microscopy, and small-angle x-ray scattering (SAXS) were used to characterize the phase behavior as a function of temperature of SCC. Liquid crystalline phase was formed with SCC. Based on the thermal properties and x-ray diffraction, it appears that SCC forms a structure analogous to the type II monolayer structure observed with cholesterol esters.

Productions and Properties of Bacterial Cellulose from Oil Palm Shoot Juices Felled Medium and Coconut Medium

2017 ◽  
Vol 728 ◽  
pp. 271-276
Author(s):  
Nantharat Phruksaphithak ◽  
Chalermkiet Kaewnun ◽  
Sompong O-Thong
Keyword(s):  
Bacterial Cellulose ◽  
Oil Palm ◽  
Chemical Structure ◽  
Fermentation Medium ◽  
Scanning Calorimetry ◽  
Cellulose Production ◽  
Bacterial Cellulose Production ◽  
X Ray ◽  
Mixing Ratios ◽  
Ft Ir

Bacterial Cellulose (BC) was produced by Acetobacterxylinum TISTR 086 use mixing of oil palm shoot juices (OPSJ) and coconut juice (CJ) medium with or without nutrient supplemented or OPSJ was digested with α-amylase. Results showed the highest yield was obtained at OPSJ with CJ at mixing ratios of 50% (4.70±0.11 g/L) and the lowest yield was obtained at OPSJ with CJ at mixing ratios of 0% (3.54±0.11 g/L). OPSJ was digested with 1300 lU/gm at concentration enzyme 650 IU/L at 37 °C for 24 h has highest sugar concentration of 73.93±0.12 g/L. Amylase digested OPSJ mixed with coconut juice’s highest bacterial cellulose production at OPSJ with CJ at mixing ratios of 50% (4.94±0.13 g/L), respectively. Moreover, the BC obtained had molecular weight from 332,122 to 503,233 g/mol. The chemical structure of BC produced was studied using Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray defections. The morphology of BC was investigated by Scanning Electron Microscopy (SEM). Thermal property was further studied using Differential Scanning Calorimetry (DSC) and Thermogravimetic Analysis (TGA). This study obviously showed the ability of OPSJ, a suitable and cheap carbon source, to be used as a substrate in a fermentation medium for production of cellulose by Acetobacterxylinum TISTR 086.

Use of diisocyanate to enhance the flame-retardant, mechanical and crystalline properties of poly (butylene succinate-co-butylene 3-hydroxyphenylphosphinyl-propionate) (PBSH)

2020 ◽  
Vol 40 (5) ◽  
pp. 409-414
Author(s):  
Tian-Xiang Jin ◽  
Miao-miao Wu ◽  
Jin-bo Ou-yang ◽  
Qin Zhang
Keyword(s):  
Chemical Structure ◽  
Oxygen Index ◽  
Hydrolysis Rate ◽  
Structure And Properties ◽  
Reactive Blending ◽  
Scanning Calorimetry ◽  
Butylene Succinate ◽  
Limiting Oxygen Index ◽  
Methylene Diphenyl Diisocyanate ◽  
Ft Ir

AbstractPoly (butylene succinate-co-butylene-3-hydroxyphenylphosphinyl-propionate) (PBSH) was synthesized through polycondensation. Then, 4,4′-methylene diphenyl diisocyanate (MDI) was introduced into PBSH matrix by reactive blending. The chemical structure and properties of the blending products were investigated using Fourier Transform Infrared Spectroscopy (FT-IR), differential scanning calorimetry (DSC), limiting oxygen index (LOI) tests, thermogravimetric analysis (TGA), and vertical burning tests. The results proved that MDI can improve the mechanical properties and flame retardancy of PBSH. In addition, it was found that the crosslinking structure can reduce the hydrolysis rate of PBSH and effectively eliminate the melt-dripping of PBSH during combustion.

Thermal Behaviour of Candesartan Active substance and in pharmaceutical compounds

2017 ◽  
Vol 68 (8) ◽  
pp. 1895-1902
Author(s):  
Ioana Cristina Tita ◽  
Eleonora Marian ◽  
Bogdan Tita ◽  
Claudia Crina Toma ◽  
Laura Vicas
Keyword(s):  
Thermal Behaviour ◽  
Active Substance ◽  
Pharmaceutical Research ◽  
Pharmaceutical Product ◽  
Nitrogen Atmosphere ◽  
Pure Substance ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir

Thermal analysis is one of the most frequently used instrumental techniques in the pharmaceutical research, for the thermal characterization of different materials from solids to semi-solids, which are of pharmaceutical relevance. In this paper, simultaneous thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) were used for characterization of the thermal behaviour of candesartan cilexetil � active substance (C-AS) under dynamic nitrogen atmosphere and nonisothermal conditions, in comparison with pharmaceutical product containing the corresponding active substance. It was observed that the commercial samples showed a different thermal profile than the standard sample, caused by the presence of excipients in the pharmaceutical product and to possible interaction of these with the active substance. The Fourier transformed infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRPD) were used as complementary techniques adequately implement and assist in interpretation of the thermal results. The main conclusion of this comparative study was that the TG/DTG and DSC curves, together with the FT-IR spectra, respectively X-ray difractograms constitute believe data for the discrimination between the pure substance and pharmaceutical forms.

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

Liquid crystalline polyureas with oligo(ethylene glycol) sequences

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
Shahram Mehdipour-Ataei ◽  
Leila Akbarian-Feizi
Keyword(s):  
Liquid Crystalline ◽  
Spectroscopic Method ◽  
Polymerization Reaction ◽  
X Ray Diffraction ◽  
Subsequent Reaction ◽  
Scanning Calorimetry ◽  
Polar Solvents ◽  
X Ray ◽  
H Nmr ◽  
Ft Ir

AbstractA diamine monomer containing ester, amide and ether functional groups was prepared and its polymerization reaction with different diisocyanates to give main chain poly(ester amide ether urea)s was investigated. The monomer was synthesized via reaction of terephthaloyl chloride with 4-hydroxybenzoic acid and subsequent reaction of the resulted diacid with 1,8-diamino-3,6-dioxaoctane. The polymers were characterized by FT-IR and 1H-NMR spectroscopic method and elemental analysis. The resulting polymers exhibited excellent solubility in polar solvents. Crystallinity of the resulted polymers was evaluated by wide-angle X-ray diffraction (WXRD) method, and they exhibited semi-crystalline patterns. The glass transition temperatures (Tg) of the polymers determined by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were in the range of 88-112 °C. The temperatures for 10% weight loss (T10) from their thermogravimetric analysis (TGA) curves were found to be in the range of 297-312 °C in air. Also the prepared polyureas showed liquid crystalline character.

Synthesis and Properties of Thermotropic Liquid Crystalline Polyesters with Flexible Polymethylene Spacer

2010 ◽  
Vol 428-429 ◽  
pp. 126-131
Author(s):  
Wei Zhong Lu ◽  
Chun Wei ◽  
Qui Shan Gao
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Structure Morphology ◽  
Temperature Ranges ◽  
Ft Ir ◽  
Diffraction Peaks ◽  
Ubbelohde Viscometer

Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (Tm), isotropic temperature (Ti) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 2θ near 19° and 23°.

Preparation and Characterization of Ni2+-Montmorillonite/Polyvinyl Alcohol Water-Soluble Nanocomposite Film

2005 ◽  
Vol 13 (8) ◽  
pp. 839-846 ◽  
Author(s):  
Li-Ping Wang ◽  
Yun-Pu Wang ◽  
Fa-Ai Zhang
Keyword(s):  
Polyvinyl Alcohol ◽  
Photoelectron Spectroscopy ◽  
Thermal Characteristics ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
Xps Spectra ◽  
X Ray ◽  
Alcohol Water ◽  
Ft Ir ◽  
Silicate Layers

A new type of nano-composite film was prepared from polyvinyl alcohol, Ni2+-montmorillonite (Ni2+-MMT), defoamer, a levelling agent and a plasticizer. Its thermal characteristics were studied by Differential Scanning Calorimetry (DSC). The intermolecular interactions were measured by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the tensile strength (TS) and elongation at break (%E) were measured. The microstructures were studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). FT-IR and XPS spectra indicated that cross-linking has taken place between PVA and Ni2+-MMT. XRD and AFM indicate that the PVA molecules had inserted themselves into the silicate layers of MMT, exfoliating them and dispersing them randomly into the PVA matrix. Compared to pure PVA film, the TS of the films was increased and %E decreased when the Ni2+-Montmorillonite was added and the dissolution temperature of the film was also reduced.

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