scholarly journals Synthesis and characterization of cyanate ester and its blends with bisphenol dicyanate ester

2008 ◽  
Vol 2 (4) ◽  
pp. 239-247
Author(s):  
Samikannu Rakesh ◽  
◽  
Muthusamy Sarojadevi ◽  
Keyword(s):  
Cyanate Ester ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Dsc Studies ◽  
Degradation Temperature ◽  
Ft Ir ◽  
Flame Retardant Properties ◽  
Lower Temperature

A new keto-ene functionalized 1, 5-bis (4-hydroxyphenyl)penta-1,4-dien-3-one (HPDO) was prepared from p-hydroxy benzaldehyde and acetone using boric acid as a catalyst. The prepared bisphenol was converted into 1,5-bis (4-cyanatophenyl) penta-1,4-diene-3-one (CPDO) by reacting with cyanogen bromide (CNBr) in the presence of triethylamine. The synthesized bisphenol and the dicyanate ester were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR) and elemental analysis (EA) techniques. CPDO was then blended with a commercial bisphenol-A dicyanate ester (BADCy) at different ratios (100:0, 75:25, 50:50. 25:75, 0:100) and the cure characteristics were studied. CPDO was found to be cured at a lower temperature than BADCy. The cyanate ester blends were cured at 373 K (30 min) → 423 K (30 min) → 473 K (60 min) → 523 K (3h). Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to study the thermal properties. DSC studies show that the cure (peak) temperature of CPDO with and without a catalyst was found to be 408 K and 466 K respectively. The initial degradation temperature of the cured resins was found to be in the range from 701 K to 705 K. The Limiting Oxygen Index (LOI) value, determined by Van Krevelen’s equation, shows that these blends have good flame retardant properties.

Thermal behaviour of benzoxazine blends based on epoxy and cyanate ester

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1475-S1485
Author(s):  
Balaji Krishnasamy ◽  
Hariharan Arumugam ◽  
Mohamed Iqbal M ◽  
Alagar Muthukaruppan
Keyword(s):  
High Performance ◽  
Analytical Techniques ◽  
Cyanate Ester ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Polymeric Matrices ◽  
Bisphenol F ◽  
Degradation Temperature ◽  
Cure Behaviour

In the present work, an attempt has been made to develop high-performance polymeric hybrid binary blends of epoxy/benzoxazine and benzoxazine/cyanate ester with varying weight percentages (25/75, 50/50 and 75/25 wt%) of resins, namely, bisphenol-F epoxy resin (DGEBF), benzoxazines [bisphenol–F/aniline (BF-a) and imidazole core-based bisphenol/aniline (IBP-a)] and cyanate ester [bisphenol-F bifunctional cyanate ester (BF-CE)]. The molecular structure, polymerisation temperature/cure behaviour, glass transition temperature (Tg) and thermal stability of the neat polymeric matrices and binary hybrid blends of polymeric matrices were characterised using different analytical techniques, viz. Fourier Transform infra-red spectroscopy (FTIR), Nuclear Magnetic Resonance spectroscopy (NMR), Differential Scanning Calorimetry (DSC) and thermogravimetric analysis (TGA). Among the binary hybrid blends, the lowest polymerisation temperatures (Tp) were noticed in the case of blends of epoxy/benzoxazine were 219°C for DGEBF/BF-a (25/75 wt%) and 170°C for DGEBF/IBP-a (25/75 wt%). Similarly, in the case of blends of benzoxazine/cyanate ester, the lowest values of Tp observed were 155°C and 153°C for BF-a/BF-CE (75/25 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. The highest values of Tg observed for the blends of epoxy/benzoxazine were 175°C and 254°C for DGEBF/BF-a (25/75 wt%) and DGEBF/IBP-a (25/75 wt%), respectively. Whereas, the highest values of Tg observed in the case of blends of benzoxazine/cyanate ester were 234°C and 278°C for BF-a/BF-CE (25/75 wt%) and IBP-a/BF-CE (75/25 wt%), respectively. From the TGA results of blends, the maximum degradation temperature (Tmax) and limiting oxygen index (LOI) value calculated from the char yield, which ascertain that almost all the binary hybrid blends of epoxy/benzoxazine and benzoxazine/cyanate ester possess good flame retardant behaviour.

Synthesis and Characterization of Novel Thermal Stability Poly (ester-imide-ether) with Excellent Lower Temperature Elastic Recovery

2012 ◽  
Vol 554-556 ◽  
pp. 258-262
Author(s):  
Jiao Jiao Shang ◽  
Jian Wu Lan ◽  
Shao Jian Lin ◽  
Si Chen ◽  
Ya Ni Li
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Elastic Recovery ◽  
Synthesis And Characterization ◽  
Scanning Calorimetry ◽  
Excellent Thermal Stability ◽  
Melt Polymerization ◽  
Ft Ir ◽  
Lower Temperature

A new poly(ester-imide-ether) (PEIE) was prepared by melt polymerization from 1,4-butanediol(BD), polytetrahydrofuran diol (PTMG) and a novel imide dicarboxylic acid monomer which was synthesized from 3,3',4,4'-biphenyltetracarboxylic di-anhydride(BPDA) and glycine acid(GLY). The structure, thermal behaviour and elastic recovery of polymer were characterized by FT-IR. thermogravimetric analysis (TGA), differential scanning calorimetry thermograms (DSC) and laboratory stretching machine. The results showed this polymer has excellent thermal stability, 5 % weight loss temperature was at 354°C. Meanwhile, the DSC curve showed that glass-transition temperature and crystallization temperature of the polymer were at -30 °C and 160 °C, respectively. The excellent elastic recovery was still displayed at low temperature.

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.

Preparation and Characterization of Soybean Oil-based Flame Retardant Rigid Polyurethane Foams Containing Phosphaphenanthrene Groups

2020 ◽  
Vol 17 (10) ◽  
pp. 760-771
Author(s):  
Qirui Gong ◽  
Niangui Wang ◽  
Kaibo Zhang ◽  
Shizhao Huang ◽  
Yuhan Wang
Keyword(s):  
Soybean Oil ◽  
Flame Retardant ◽  
Chemical Structure ◽  
Cell Structure ◽  
Polyurethane Foams ◽  
Limiting Oxygen Index ◽  
Rigid Polyurethane Foams ◽  
Degradation Activation Energy ◽  
Ft Ir

A phosphaphenanthrene groups containing soybean oil based polyol (DSBP) was synthesized by epoxidized soybean oil (ESO) and 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide (DOPO). Soybean oil based polyol (HSBP) was synthesized by ESO and H2O. The chemical structure of DSBP and HSBP were characterized with FT-IR and 1H NMR. The corresponding rigid polyurethane foams (RPUFs) were prepared by mixing DSBP with HSBP. The results revealed apparent density and compression strength of RPUFs decreased with increasing the DSBP content. The cell structure of RPUFs was examined by scanning electron microscope (SEM) which displayed the cells as spherical or polyhedral. The thermal degradation and flame retardancy of RPUFs were investigated by thermogravimetric analysis, limiting oxygen index (LOI), and UL 94 vertical burning test. The degradation activation energy (Ea) of first degradation stage reduced from 80.05 kJ/mol to 37.84 kJ/mol with 80 wt% DSBP. The RUPF with 80 wt% DSBP achieved UL94 V-0 rating and LOI 28.3. The results showed that the flame retardant effect was mainly in both gas phase and condensed phase.

scholarly journals Synthesis and Characterization of N-Substituted Polyether-Block-Amide Copolymers

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 773
Author(s):  
Jyun-Yan Ye ◽  
Kuo-Fu Peng ◽  
Yu-Ning Zhang ◽  
Szu-Yuan Huang ◽  
Mong Liang
Keyword(s):  
Titanium Isopropoxide ◽  
Decomposition Temperature ◽  
Phenyl Isocyanate ◽  
Cross Linking ◽  
Resonance Spectroscopy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Melt Polycondensation ◽  
Structural Regularity

A series of N-substituted polyether-block-amide (PEBA-X%) copolymers were prepared by melt polycondensation of nylon-6 prepolymer and polytetramethylene ether glycol at an elevated temperature using titanium isopropoxide as a catalyst. The structure, thermal properties, and crystallinity of PEBA-X% were investigated using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, and thermogravimetric analysis. In general, the crystallinity, melting point, and thermal degradation temperature of PEBA-X% decreased as the incorporation of N-methyl functionalized groups increased, owing to the disruption caused to the structural regularity of the copolymer. However, in N-acetyl functionalized analogues, the crystallinity first dropped and then increased because of a new γ form arrangement that developed in the microstructure. After the cross-linking reaction of the N-methyl-substituted derivative, which has electron-donating characteristics, with poly(4,4′-methylenebis(phenyl isocyanate), the decomposition temperature of the resulting polymer significantly increased, whereas no such improvements could be observed in the case of the electro-withdrawing N-acetyl-substituted derivative, because of the incompleteness of its cross-linking reaction.

Synthesis, Characterization and Application of Multi-Generations Hyperbranched Polyurethane Based on Isophorone Diisocyanate

2012 ◽  
Vol 554-556 ◽  
pp. 126-129 ◽  
Author(s):  
Shun Yin ◽  
Ning Sun ◽  
Chun Yun Feng ◽  
Zhi Mou Wu ◽  
Zhao Hua Xu ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Raw Materials ◽  
Degradation Mechanism ◽  
Resonance Spectroscopy ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Isophorone Diisocyanate ◽  
Scanning Calorimetry ◽  
Degradation Temperature ◽  
Hyperbranched Polyurethane

A series of different generation hyperbranched polyurethane(HBPU) was synthesized based on the raw materials of isophorone diisocyanate(IPDI) and diethanolamine(DEOA). Their structure, thermal degradation mechanism and glass transition temperature(Tg) were characterized by fourier transform infrared spectroscopy(FTIR), nuclear magnetic resonance spectroscopy(NMR), thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC). The results showed that: the yield of each generation HBPU was up to 90%, different generation HBPU had almost the same initial degradation temperature(about at 200°C) and they all had two decomposition platforms; with the increase of generation, Tg increased from 107.2°C to 132.1°C. The gloss and hardness of the HBPU coatings were significantly improved.

scholarly journals ISOLATION OF 2-CHLOROBENZIMIDAZOLE FROM MELIA DUBIA LEAF EXTRACT AND ITS STRUCTURAL CHARACTERISATION

2017 ◽  
Vol 9 (10) ◽  
pp. 67 ◽  
Author(s):  
G. Dayana Jeyaleela ◽  
S. Irudaya Monisha ◽  
J. Rosaline Vimala ◽  
A. Anitha Immaculate
Keyword(s):  
Mass Spectrometry ◽  
1H Nmr ◽  
Research Work ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Ft Ir ◽  
Uv Visible ◽  
Isolated Compound ◽  
Promising Source

Objective: Natural products from medicinal plants, either as isolated compounds or as standardized plant extracts exhibit promising source of medicinal activity against various diseases. The aim of the present work was to make an attempt of isolation of bioactive principle and characterization of the isolated compound, from the medicinal plant Melia dubaiMethods: The extraction was done by a cold percolation method and the compound was separated and isolated by chromatography technique such as a thin layer chromatography (TLC), column chromatography and high-performance liquid chromatography (HPLC). The isolated compound was crystallized and the structural characterization of the isolated compound was made using UV-Visible, FT-IR, 1H-NMR, GC-MS and MS techniques which confirmed the structure of the isolated compound.Results: The separated and isolated compound was characterized by both physical and spectral methods like Ultraviolet-Visible spectroscopy (UV-Visible), Fourier transform infrared spectroscopy (FT-IR), Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), Gas chromatography-mass spectrometry (GC-MS), and Mass spectrometry(MS). Based on the studies, organizational characteristics of one bioactive principle were deciphered. The results revealed that the isolated species is 2-chlorobenzimidazole and it agreed well with the reported value and spectra for 2-chlorobenzimidazole.Conclusion: The above results obtained in this research work clearly indicated the promising occurrence of 2-chlorobenzimidazole in Media dubia plant leaves. The future scope of these studies may guide us to view the biological activity of the isolated compound.

scholarly journals THE PHYSICOCHEMICAL CHARACTERISTICS OF RECYCLED-PLASTIC PELLETS OBTAINED FROM DISPOSABLE FACE MASK WASTES

2021 ◽  
Vol 23 (1) ◽  
pp. 16
Author(s):  
Vienna Saraswaty ◽  
Rossy Choerun Nissa ◽  
Bonita Firdiana ◽  
Akbar Hanif Dawam Abdullah
Keyword(s):  
Tensile Strength ◽  
Physicochemical Characterization ◽  
Face Mask ◽  
Physicochemical Characteristics ◽  
Scanning Calorimetry ◽  
Elongation At Break ◽  
Ft Ir ◽  
The Government ◽  
Plastic Pellets

THE PHYSICOCHEMICAL CHARACTERISTICS OF RECYCLED-PLASTIC PELLETS OBTAINED FROM DISPOSABLE FACE MASK WASTES. The government policy to wear a face mask during the COVID-19 pandemic has increased disposable face mask wastes. Thus, to reduce such wastes, it is necessary to evaluate the physicochemical characteristics of disposable face masks wastes before the recycling process and the recycled products. In this study, physicochemical characterization of the 3-ply disposable face masks and the recycled plastic pellets after disinfection using 0.5% v/v sodium hypochlorite were evaluated. A set of parameters including the characterization of surface morphology by a scanning electron microscope (SEM), functional groups properties by a fourier transform infra-red spectroscopy (FT-IR), thermal behavior by a differential scanning calorimetry (DSC), tensile strength and elongation at break were evaluated. The surface morphological of each layer 3-ply disposable face mask showed that the layers were composed of non-woven fibers. The FT-IR evaluation revealed that 3-ply disposable face mask was made from a polypropylene. At the same time, the DSC analysis found that the polypropylene was in the form of homopolymer. The SEM analysis showed that the recycled plastic pellets showed a rough and uneven surface. The FT-IR, tensile strength and elongation at break of the recycled plastic pellets showed similarity with a virgin PP type CP442XP and a recycled PP from secondary recycling PP (COPLAST COMPANY). In summary, recycling 3-ply disposable face mask wastes to become plastic pellets is recommended for handling disposable face mask wastes problem.

Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization

2014 ◽  
Vol 34 (7) ◽  
pp. 611-616 ◽  
Author(s):  
Shijie Cheng ◽  
Jun Xu ◽  
Yumin Wu
Keyword(s):  
Emulsion Polymerization ◽  
Butyl Acrylate ◽  
Colloidal Stability ◽  
Graft Copolymerization ◽  
Scanning Calorimetry ◽  
Oxidized Starch ◽  
Ir Transmission ◽  
Ft Ir ◽  
Synthetic Latex

Abstract Oxidized starch-graft-poly(styrene-butyl acrylate) [OS-g-P(St-BA)] latex was synthesized by the graft copolymerization of OS with St and n-butyl acrylate (BA) via emulsion polymerization. The graft copolymers were characterized by Fourier transform infrared (FT-IR), transmission electronic microscopy (TEM), dynamic light scattering, thermogravimetry (TG), and differential scanning calorimetry (DSC). The effects of the amount of OS, monomers, and initiator on graft copolymerization were investigated. Under the optimal conditions, the percentage of graft (PG), grafting efficiency (GE), and ζ potential could reach 256.5%, 41.7%, and -30.1 mV, respectively. The results indicated that the OS grafted onto particles greatly enhanced the colloidal stability of latex. The thermal stability properties of OS-g-P(St-BA) were also improved by the addition of OS. The OS-g-P(St-BA) latex may be used to partly replace the conventional synthetic latex for paper coating.

scholarly journals Formulation and Characterization of Aceclofenac-Loaded Nanofiber Based Orally Dissolving Webs

Pharmaceutics ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 417 ◽  
Author(s):  
Emese Sipos ◽  
Nóra Kósa ◽  
Adrienn Kazsoki ◽  
Zoltán-István Szabó ◽  
Romána Zelkó
Keyword(s):  
Oral Absorption ◽  
Vinyl Pyrrolidone ◽  
Drug Dissolution ◽  
In Vitro Dissolution ◽  
Drug Release Profile ◽  
Scanning Calorimetry ◽  
Ft Ir ◽  
Fast Dissolution ◽  
Poly Vinyl Pyrrolidone

Aceclofenac-loaded poly(vinyl-pyrrolidone)-based nanofiber formulations were prepared by electrospinning to obtain drug-loaded orally disintegrating webs to enhance the solubility and dissolution rate of the poorly soluble anti-inflammatory active that belongs to the BCS Class-II. Triethanolamine-containing ternary composite of aceclofenac-poly(vinyl-pyrrolidone) nanofibers were formulated to exert the synergistic effect on the drug-dissolution improvement. The composition and the electrospinning parameters were changed to select the fibrous sample of optimum fiber characteristics. To determine the morphology of the nanofibers, scanning electron microscopy was used. Fourier transform infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) were applied for the solid-state characterization of the samples, while the drug release profile was followed by the in vitro dissolution test. The nanofibrous formulations had diameters in the range of few hundred nanometers. FT-IR spectra and DSC thermograms indicated the amorphization of aceclofenac, which resulted in a rapid release of the active substance. The characteristics of the selected ternary fiber composition (10 mg/g aceclofenac, 1% w/w triethanolamine, 15% w/w PVPK90) were found to be suitable for obtaining orally dissolving webs of fast dissolution and potential oral absorption.

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