Water Interactions in Hybrid Polyacrylate-Silicate Hydrogel Systems

Hybrid polyacrylate-silicate hydrogels were obtained in the presence of N,N′-methylenebisacrylamide (NNMBA) as the cross-linking monomer and sodium thiosulphate/potassium persulphate (NTS/KPS) as the redox initiators. The results of the tests allowed us to conclude that a hybrid structure with a polyacrylate scaffolding and a silicate matrix had been obtained. The results of the rheological analysis revealed that the hydrogel sample with a 1:7 mass ratio of sodium water glass to the sodium polyacrylate is characterized by the highest complex viscosity. Thermal analysis (Thermogravimetry/Differential Scanning Calorimetry (TG/DSC)) showed that water begins to evaporate at higher temperatures, from 120 °C to even 180 °C. These results were confirmed by mid-infrared spectroscopy (MIR) and nuclear magnetic resonance spectroscopy (NMR) analysis. Differences in the intensity of the peaks derived from water in the MIR spectra indicate that most of the water is bounded. In turn, NMR results showed that the mobility of water molecules decreases as the amount of sodium water glass in the mixture increases.

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Rheological, Thermal, Superficial, and Morphological Properties of Thermoplastic Achira Starch Modified with Lactic Acid and Oleic Acid

Molecules ◽

10.3390/molecules24244433 ◽

2019 ◽

Vol 24 (24) ◽

pp. 4433 ◽

Cited By ~ 2

Author(s):

Carolina Caicedo ◽

Rocío Yaneli Aguirre Loredo ◽

Abril Fonseca García ◽

Omar Hernán Ossa ◽

Aldo Vázquez Arce ◽

...

Keyword(s):

Lactic Acid ◽

Oleic Acid ◽

Complex Viscosity ◽

Thermoplastic Starch ◽

Residual Energy ◽

Morphological Properties ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Rheological Analysis ◽

Acid Agent

The modification of achira starch a thermoplastic biopolymer is shown. Glycerol and sorbitol, common plasticizers, were used in the molten state with organic acids such as oleic acid and lactic acid obtaining thermodynamically more stable products. The proportion of starch:plasticizer was 70:30, and the acid agent was added in portions from 3%, 6%, and 9% by weight. These mixtures were obtained in a torque rheometer for 10 min at 130 °C. The lactic acid managed to efficiently promote the gelatinization process by increasing the available polar sites towards the surface of the material; as a result, there were lower values in the contact angle, these results were corroborated with the analysis performed by differential scanning calorimetry and X-ray diffraction. The results derived from oscillatory rheological analysis had a viscous behavior in the thermoplastic starch samples and with the presence of acids; this behavior favors the transitions from viscous to elastic. The mixture of sorbitol or glycerol with lactic acid promoted lower values of the loss module, the storage module, and the complex viscosity, which means lower residual energy in the transition of the viscous state to the elastic state; this allows the compounds to be scaled to conventional polymer transformation processes.

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Synthesis and properties of a novel high-temperature vinylpyridine-based phthalonitrile polymer

High Performance Polymers ◽

10.1177/0954008318801911 ◽

2018 ◽

Vol 31 (7) ◽

pp. 820-830 ◽

Cited By ~ 3

Author(s):

Haifeng Wang ◽

Zhenjiang Zhang ◽

Puguang Ji ◽

Xiaoyan Yu ◽

Kimiyoshi Naito ◽

...

Keyword(s):

Complex Viscosity ◽

Mechanical Analysis ◽

Curing Temperature ◽

Gravimetric Analysis ◽

Test Results ◽

Scanning Calorimetry ◽

Excellent Thermal Stability ◽

Rheological Analysis ◽

Dsc Analyses ◽

Low Complex

A novel vinylpyridine-based phthalonitrile monomer, 2,6-bis[3-(3,4-dicyanophenoxy)styryl]pyridine (BDSP), was resoundingly produced by a nucleophilic substitution reaction of 2,6-bis(3-hydroxystyryl)pyridine with 4-nitrophthalonitrile in the presence of potassium carbonate. The chemical structure of the synthesized BDSP was confirmed by proton (1H) and carbon (12C) nuclear magnetic resonance (NMR) as well as Fourier transform infrared (FTIR) analysis. The curing behavior of BDSP was investigated by FTIR and differential scanning calorimetry (DSC) analyses. The resin showed a low complex viscosity in the wide processing window between the monomer melting temperature and the curing temperature of the polymer, as discovered by rheological analysis. In addition, the properties of the polymer were studied by thermal gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Based on the test results, the BDSP polymer demonstrated superior processing performance, excellent thermal stability, outstanding mechanical properties, and low water uptake, and these advanced performance characteristics are critical to many fields.

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Effect of Extrusion Screw Speed and Plasticizer Proportions on the Rheological, Thermal, Mechanical, Morphological and Superficial Properties of PLA

Polymers ◽

10.3390/polym12092111 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2111

Author(s):

Jaime Gálvez ◽

Juan Correa Aguirre ◽

Miguel Hidalgo Salazar ◽

Bairo Vera Mondragón ◽

Elizabeth Wagner ◽

...

Keyword(s):

Loss Modulus ◽

Complex Viscosity ◽

Processing Parameters ◽

Extrusion Process ◽

Mechanical Analysis ◽

Residual Energy ◽

Poly Lactic Acid ◽

Scanning Calorimetry ◽

Rheological Analysis ◽

Acetyl Tributyl Citrate

One of the critical processing parameters—the speed of the extrusion process for plasticized poly (lactic acid) (PLA)—was investigated in the presence of acetyl tributyl citrate (ATBC) as plasticizer. The mixtures were obtained by varying the content of plasticizer (ATBC, 10–30% by weight), using a twin screw extruder as a processing medium for which a temperature profile with peak was established that ended at 160 °C, two mixing zones and different screw rotation speeds (60 and 150 rpm). To evaluate the thermo-mechanical properties of the blend and hydrophilicity, the miscibility of the plasticizing and PLA matrix, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), oscillatory rheological analysis, Dynamic Mechanical Analysis (DMA), mechanical analysis, as well as the contact angle were tested. The results derived from the oscillatory rheological analysis had a viscous behavior in the PLA samples with the presence of ATBC; the lower process speed promotes the transitions from viscous to elastic as well as higher values of loss modulus, storage modulus and complex viscosity, which means less loss of molecular weight and lower residual energy in the transition from the viscous state to the elastic state. The mechanical and thermal performance was optimized considering a greater capacity in the energy absorption and integration of the components.

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Synthesis and properties of pyrazine-based oligomeric phthalonitrile resins

High Performance Polymers ◽

10.1177/0954008318823894 ◽

2019 ◽

Vol 31 (9-10) ◽

pp. 1075-1084 ◽

Cited By ~ 5

Author(s):

Yao Liu ◽

Puguang Ji ◽

Zhenjiang Zhang ◽

Xiaoyan Yu ◽

Kimiyoshi Naito ◽

...

Keyword(s):

Complex Viscosity ◽

Resonance Spectroscopy ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

One Pot ◽

X Ray ◽

Tetragonal System ◽

End Capping ◽

Initial Storage ◽

Reaction Activation Energy

The pyrazine-based oligomeric phthalonitrile (PN) monomer, 2,6-bis[3-(3,4-dicyanophenoxy)phenoxy]pyrazine (BCPP), was synthesized from the reaction of an excess amount of resorcinol with 2,6-dichloropyrazine in the presence of potassium carbonate, followed by end-capping with 4-nitrophthalonitrile in a two-step, one-pot reaction. 4-(Aminophenoxy)phthalonitrile was applied to promote the curing reaction. The curing behavior was investigated by differential scanning calorimetry and rheological behavior, showing a wide processing window of 94°C, a complex viscosity of less than 1.5 Pa·s and a lower reaction activation energy of 32.57 kJ mol−1. The structure of the BCPP monomer was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The unit cell was determined to be tetragonal system by wide-angle X-ray diffraction. The monomer was cured to yield cross-linked polymers, which exhibited a high initial storage modulus, excellent glass transition temperature, outstanding thermal stability, and low water uptake.

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Physicochemical properties and structural dynamics of organic–inorganic hybrid [NH3(CH2)3NH3]ZnX4 (X = Cl and Br) crystals

Scientific Reports ◽

10.1038/s41598-021-87940-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ae Ran Lim ◽

Sun Ha Kim ◽

Yong Lak Joo

Keyword(s):

Structural Dynamics ◽

Chemical Shifts ◽

Lattice Relaxation ◽

Magic Angle Spinning ◽

Spin Lattice Relaxation ◽

Resonance Spectroscopy ◽

Magic Angle ◽

Scanning Calorimetry ◽

Inorganic Hybrid ◽

Halogen Atoms

AbstractThe physical properties of the organic–inorganic hybrid crystals having the formula [NH3(CH2)3NH3]ZnX4 (X = Cl, Br) were investigated. The phase transition temperatures (TC; 268K for Cl and 272K for Br) of the two crystals bearing different halogen atoms in their skeletons were determined through differential scanning calorimetry. The thermodynamic properties of the two crystals were investigated through thermogravimetric analysis. The structural dynamics, particularly the role of the [NH3(CH2)3NH3] cation, were probed through 1H and 13C magic-angle spinning nuclear magnetic resonance spectroscopy as a function of temperature. The 1H and 13C NMR chemical shifts did not show any changes near TC. In addition, the 1H spin–lattice relaxation time (T1ρ) varied with temperature, whereas the 13C T1ρ values remained nearly constant at different temperatures. The T1ρ values of the atoms in [NH3(CH2)3NH3]ZnCl4 were higher than those in [NH3(CH2)3NH3]ZnBr4. The observed differences in the structural dynamics obtained from the chemical shifts and T1ρ values of the two compounds can be attributed to the differences in the bond lengths and halogen atoms. These findings can provide important insights or potential applications of these crystals.

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Synthesis and properties of phthalonitrile-based resins containing spirocycle acetal

High Performance Polymers ◽

10.1177/0954008320977594 ◽

2020 ◽

pp. 095400832097759

Author(s):

Ke Li ◽

Hua Yin ◽

Kun Yang ◽

Pei Dai ◽

Ling Han ◽

...

Keyword(s):

Thermal Stability ◽

Chemical Structure ◽

Room Temperature ◽

Laser Desorption Ionization ◽

Scanning Calorimetry ◽

Rheological Analysis ◽

Ionization Time ◽

Dynamic Mechanical ◽

Nmr Spectrometry ◽

Current Context

Designing novel low-melting, high-rigidity phthalonitrile resin is of great significance in the current context of development. In this study, rigid spirocycle acetal structure was introduced into phthalonitrile to reduce the melting point and maintain their thermal stability. The chemical structure of resins was confirmed by nuclear magnetic resonance (NMR) spectrometry, matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry and Fourier-transform infrared (FTIR) spectroscopy. The curing behaviors were studied by differential scanning calorimetry (DSC). Thermal stability and mechanical properties of the cured resins were investigated by dynamic mechanical thermal analysis (DMTA) and thermogravimetric analysis (TGA). The processability was studied by rheological analysis. The results indicated the three monomers had a low melting temperature, wide processing windows and low viscosities. These polymers did not exhibit Tg from room temperature to 400°C, exhibited superb dynamic mechanical property and thermal stability.

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

Materials ◽

10.3390/ma14040773 ◽

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.

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Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽

10.3390/polym11121915 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1915 ◽

Cited By ~ 2

Author(s):

Eyob Wondu ◽

Hyun Woo Oh ◽

Jooheon Kim

Keyword(s):

Molecular Weight ◽

Contact Angle ◽

Polyethylene Glycol ◽

Photoelectron Spectroscopy ◽

Water Solubility ◽

Soft Segment ◽

Water Soluble ◽

Size Exclusion ◽

Resonance Spectroscopy ◽

Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.554-556.126 ◽

2012 ◽

Vol 554-556 ◽

pp. 126-129 ◽

Cited By ~ 3

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.

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Extrem asymmetrisch gebundene Wassermoleküle-Kristallstrukturen von Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O und Ba(OH)I·4 H2O / Extremely Asymmetrically Bound Water Molecules-Crystal Structures of Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O, and Ba(OH)I·4 H2O

Zeitschrift für Naturforschung B ◽

10.1515/znb-1991-1001 ◽

1991 ◽

Vol 46 (10) ◽

pp. 1279-1286 ◽

Cited By ~ 7

Author(s):

Thomas Kellersohn ◽

Konrad Beckenkamp ◽

Heinz Dieter Lutz

Keyword(s):

Crystal Structures ◽

Bound Water ◽

Structure Type ◽

Water Molecules ◽

Halide Ions ◽

Weak Hydrogen Bond ◽

Scanning Calorimetry ◽

Unknown Structure ◽

Stretching Vibrations ◽

Strong Distortion

The crystal structures of isotypic Sr(OH)Cl ·4 H2O, Sr(OH)Br·4 H2O, and Ba(OH)I·4 H2O are reported. The title compounds crystallize in a hitherto unknown structure type, space group PĪ, Z = 2. The final R values obtained are 0.0261, 0.069, and 0.062, respectively. The coordination of the metal ions is monocapped square antiprismatic with 7 H2O, 1 OH- and 1 halide ion. The halide ions separate metal/water/hydroxide layers. Each of the four crystallographically different water molecules serves as donor for one very strong and one very weak hydrogen bond and, hence, is extremely asymmetrically bound. Owing to this strong distortion, the largest one known so far, the OH stretching vibrations of the H2O molecules are intramolecularly decoupled as shown from vibrational spectra. The enthalpies of dehydration obtained from differential scanning calorimetry are reported.

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