scholarly journals Dental Composition Modified with Aryloxyphosphazene Containing Carboxyl Groups

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1176
Author(s):  
Evgeniy M. Chistyakov ◽  
Natalya Kolpinskaya ◽  
Vera Posokhova ◽  
Vladimir Chuev
Keyword(s):  
Water Sorption ◽  
Water Solubility ◽  
13C Nmr Spectroscopy ◽  
Optimal Conditions ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Dental Tissues ◽  
Dsc Method ◽  
Dental Restorative ◽  
Elastic Modules

A modifier consisting of the mixture of cyclotriphosphazenes containing 4-allyl-2-methoxyphenoxy and β-carboxyethenylphenoxy moieties was developed for administration with acrylate dental restorative compositions. The synthesized compounds were characterized by 1H and 13C NMR spectroscopy and MALDI-TOF mass spectrometry. The optimal conditions to combine the modifier with the starting dental mixture consisting of bis-GMA and TGM-3 were revealed by differential scanning calorimetry (DSC) method. Properties of the cured modified compositions were evaluated for the compliance with requirements of ISO 4049:2019. It was found that these compositions possess the increased adhesion to dental tissues and cure depth and the decreased water sorption and water solubility. The values of elastic modules, destructive compressive stress and microhardness were also increasing along with the increased content of the modifier in the composition.

scholarly journals Novel Urethane-Dimethacrylate Monomers and Compositions for Use as Matrices in Dental Restorative Materials

2020 ◽  
Vol 21 (7) ◽  
pp. 2644 ◽  
Author(s):  
Izabela M. Barszczewska-Rybarek ◽  
Marta W. Chrószcz ◽  
Grzegorz Chladek
Keyword(s):  
Water Sorption ◽  
Water Solubility ◽  
Triethylene Glycol ◽  
Degree Of Conversion ◽  
Dental Composite ◽  
Polymerization Shrinkage ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Urethane Dimethacrylate ◽  
Dental Restorative

In this study, novel urethane-dimethacrylate monomers were synthesized from 1,3-bis(1-isocyanato-1-methylethyl)benzene (MEBDI) and oligoethylene glycols monomethacrylates, containing one to three oxyethylene groups. They can potentially be utilized as matrices in dental restorative materials. The obtained monomers were used to prepare four new formulations. Two of them were solely composed of the MEBDI-based monomers. In a second pair, a monomer based on triethylene glycol monomethacrylate, used in 20 wt.%, was replaced with triethylene glycol dimethacrylate (TEGDMA), a reactive diluent typically used in dental materials. For comparison purposes, two formulations, using typical dental dimethacrylates (bisphenol A glycerolate dimethacrylate (Bis-GMA), urethane-dimethacrylate (UDMA) and TEGDMA) were prepared. The monomers and mixtures were tested for the viscosity and density. The homopolymers and copolymers, obtained via photopolymerization, were tested for the degree of conversion, polymerization shrinkage, water sorption and solubility, hardness, flexural strength and modulus. The newly developed formulations achieved promising physico-chemical and mechanical characteristics so as to be suitable for applications as dental composite matrices. A combination of the MEBDI-based urethane-dimethacrylates with TEGDMA resulted in copolymers with a high degree of conversion, low polymerization shrinkage, low water sorption and water solubility, and good mechanical properties. These parameters showed an improvement in relation to currently used dental formulations.

scholarly journals Synthesis, Thermal and Optical Characterizations of New Lateral Organic Systems

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 551
Author(s):  
Laila Ahmed. Al-Mutabagani ◽  
Latifah A. Alshabanah ◽  
Sobhi M. Gomha ◽  
Hoda A. Ahmed
Keyword(s):  
Methoxy Group ◽  
13C Nmr Spectroscopy ◽  
Molecular Structures ◽  
Phenyl Ester ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Polarized Optical Microscopy ◽  
Organic Systems ◽  
Temperature Ranges ◽  
Ft Ir

New laterally OCH3-substituted optical organic Schiff base/ester series, namely 4-(4-(hexyloxyphenyl)iminomethyl)-3-methoxyphenyl 4-alkoxybenzoates, were prepared and characterized with different thermal, mesomorphic, and photoactive techniques. The prepared group constitutes five homologues that differ from each other in the number of carbons in the terminal alkoxy chain (n), which varies between n = 6, 8, 10, 12, and 16 carbons. The laterally protruded methoxy group is attached to the central benzene ring that makes an angle of 120° with the molecular long axis. Molecular structures of all newly prepared homologues were fully elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic transitions were determined via differential scanning calorimetry (DSC) and the phases identified by polarized optical microscopy (POM). Independent of the length of the terminal alkoxy chain attached to phenyl ester ring, only a monomorphic nematic (N) phase was observed for all the synthesized compounds. A comparative study was made between the present lateral methoxy-substituted homologues and their corresponding laterally-neat analogues. The results revealed that, depending on the length of the alkoxy chain and the presence or absence of the lateral methoxy group, different mesophases with different thermal stability and temperature ranges were observed. Finally, UV-vis spectra showed that the present nematogenic series possess photoactive properties that are of importance for many applications.

scholarly journals Optical and Thermal Investigations of New Schiff Base/Ester Systems in Pure and Mixed States

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1687
Author(s):  
Abeer S. Altowyan ◽  
Hoda A. Ahmed ◽  
Sobhi M. Gomha ◽  
Ayman M. Mostafa
Keyword(s):  
13C Nmr Spectroscopy ◽  
Molecular Structures ◽  
Mixed States ◽  
Scanning Calorimetry ◽  
1H And 13C Nmr ◽  
Meta Position ◽  
Binary Phase Diagrams ◽  
Thermal Investigations ◽  
Ester Moiety ◽  
Ft Ir

New mesomorphic series, 4-hexadecyloxy phenyl-imino-4′-(3-methoxyphenyl)-4″-alkoxybenzoates (An), were prepared and investigated with different thermal and mesomorphic techniques. The synthesized homologous series constitutes four members that differ from each other in the terminal length of flexible chain (n) attached to phenyl ester moiety, which varies between n = 6, 8, 10, and 12 carbons. A lateral CH3O group is attached to the central benzene ring in the meta position with respect to the ester moiety. Molecular structures of all newly prepared homologues were elucidated via FT-IR, 1H and 13C NMR spectroscopy. Mesomorphic and thermal properties were examined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and the mesophases identified by polarized optical microscopy (POM). DSC and POM examinations revealed that all members of the present series (An) exhibit a purely enantiotropic nematic (N) phase. Comparative evaluations and binary phase diagrams were established between the present homologues and their corresponding shorter one (Bn). The examination revealed that, the length of the flexible alkoxy chain incorporated into the phenylimino moiety is highly effective on the temperature range and stability of the mesophase observed. With respect to the binary mixtures An/Bn, the exhibited N phase showed to cover the whole composition range with eutectic behavior.

Differentiated Scanning Calorimetry of Model Systems with Cocoa Butter

Food Industry ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 29-36
Author(s):  
Alexander Vereshchagin ◽  
Irina Reznichenko ◽  
Nikolay Bychin
Keyword(s):  
Cocoa Butter ◽  
Palm Olein ◽  
Palm Stearin ◽  
Model Systems ◽  
Scanning Calorimetry ◽  
Glucose Syrup ◽  
Polymorphic Modifications ◽  
Confectionery Products ◽  
System Temperature ◽  
Dsc Method

The article concerns the research specificity of model systems such as cocoa butter – palm olein, cocoa butter – sucrose and cocoa butter – glucose syrup by the differential scanning calorimetry (DSC) method. The researchers run experiments in the temperature range from –100 to –50°C at a heating rate of 10 °C/min. In the cacao butter – palm olein system an eutectic occurs with a palm olein content of 30.0 % indicating the limited solubility of palm olein in cocoa butter. In the cocoa butter – sucrose system, cocoa butter crystallizes as in the α-form (10,0– 30,0; 60.0–90.0 % MK), and as a mixture of α-and β-forms of MK (40.0; 50,0; 70,0 and 80.0 %). Sucrose stabilizes low-temperature polymorphic modifications of cocoa butter. In the cocoa butter – glucose syrup system, temperature of samples melting is 21-22 °C. This composition is promising for use as a filling of confectionery products and glazes production. In this regard, a man can use glucose syrup only in the candy cases production. The role of surfactants used for the formation and stabilization of cocoa butter polymorphs and increasing the thermal stability of the shock-lad without the introduction of palm stearin requires separate consideration.

An Unprecedented Cyano-Induced Sodium Nitrite-Catalyzed C(sp3)-H and C(sp2)-H Coupling Reaction

2018 ◽  
Vol 15 (7) ◽  
pp. 989-994 ◽  
Author(s):  
Ling Li ◽  
Bo Su ◽  
Yuxiu Liu ◽  
Qingmin Wang
Keyword(s):  
Sodium Nitrite ◽  
Oxidative Coupling ◽  
High Resolution Mass Spectrometry ◽  
Coupling Reaction ◽  
13C Nmr Spectroscopy ◽  
Coupling Reactions ◽  
Reaction Conditions ◽  
1H And 13C Nmr ◽  
Oxidative Coupling Reaction ◽  
Oxidative Coupling Reactions

Aim and Objective: During the investigation of sodium nitrite-catalyzed oxidative coupling reaction of aryls, an unprecedented C(sp2)-H and C(sp3)-H coupling of substituted 2-aryl acetonitrile was found. Materials and Methods: The structure of the coupled product was confirmed by 1H and 13C NMR spectroscopy and high-resolution mass spectrometry (HRMS), and comparison of its derivatives with known compounds. The effects of methoxy group in the benzene ring on the reaction were evaluated. Results: The optimized reaction conditions are summarized as follows: CF3SO3H/substrate = 1.5 equiv., NaNO2/substrate = 0.3 equiv., CH3CN as solvent. 2-(4-Methoxyphenyl)acetonitrile and 2-(3,4,5- trimethoxyphenyl)acetonitrile could also generate C(sp2)-H and C(sp3)-H coupling. The coupling reaction occurred as a typical radial mechanism. Conclusion: An unprecedented cyano-induced, NaNO2-catalyzed oxidative C(sp3)-H and C(sp2)-H coupling was reported. The reaction proceeded under very mild conditions, using O2 in the air as terminal oxidant. The unique oxidative manner might provide more inspiration for the development of intriguing oxidative coupling reactions.

scholarly journals (2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol

Molbank ◽  
10.3390/m1140 ◽  
2020 ◽  
Vol 2020 (2) ◽  
pp. M1140
Author(s):  
Jack Bennett ◽  
Paul Murphy
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
13C Nmr ◽  
Conjugate Addition ◽  
13C Nmr Spectroscopy ◽  
One Pot ◽  
1H And 13C Nmr ◽  
Esi Mass Spectrometry ◽  
The One

(2S,3R,6R)-2-[(R)-1-Hydroxyallyl]-4,4-dimethoxy-6-methyltetrahydro-2H-pyran-3-ol was isolated in 18% after treating the glucose derived (5R,6S,7R)-5,6,7-tris[(triethylsilyl)oxy]nona-1,8-dien-4-one with (1S)-(+)-10-camphorsulfonic acid (CSA). The one-pot formation of the title compound involved triethylsilyl (TES) removal, alkene isomerization, intramolecular conjugate addition and ketal formation. The compound was characterized by 1H and 13C NMR spectroscopy, ESI mass spectrometry and IR spectroscopy. NMR spectroscopy was used to establish the product structure, including the conformation of its tetrahydropyran ring.

scholarly journals Enhancing Toughness and Reducing Volumetric Shrinkage for Bis-GMA/TEGDMA Resin Systems by Using Hyperbranched Thiol Oligomer HMDI-6SH

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2817
Author(s):  
Biao Yu ◽  
Jingwei He ◽  
Sufyan Garoushi ◽  
Pekka K. Vallittu ◽  
Lippo Lassila
Keyword(s):  
Water Sorption ◽  
Water Solubility ◽  
Click Reaction ◽  
Raw Materials ◽  
Triethylene Glycol ◽  
Bending Test ◽  
Volumetric Shrinkage ◽  
Dental Resin ◽  
System A ◽  
Double Bond Conversion

In order to improve the toughness and reduce polymerization shrinkage of traditional bisphenol A-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) based dental resin system, a hyperbranched thiol oligomer (HMDI-6SH) was synthesized via thiol-isocyanate click reaction using pentaerythritol tetra(3-mercaptopropionate (PETA) and dicyclohexylmethane 4,4′-diisocyanate (HMDI) as raw materials. Then HMDI-6SH was mixed with 1,3,5-Triallyl-1,3,5-Triazine-2,4,6(1H,3H,5H)-Trione (TTT) to prepare thiol-ene monomer systems, which were added into Bis-GMA/TEGDMA resins with different mass ratio from 10 wt% to 40 wt% to serve as anti-shrinking and toughening agent. The physicochemical properties of these thiol-ene-methacrylate ternary resins including functional groups conversion, volumetric shrinkage, flexural properties, water sorption, and water solubility were evaluated. The results showed that the incorporation of HMDI/TTT monomer systems into Bis-GMA/TEGDMA based resin could improve C=C double bond conversion from 62.1% to 82.8% and reduced volumetric shrinkage from 8.53% to 4.92%. When the mass fraction of HMDI/TTT monomer systems in the resins was no more than 20 wt%, the flexural strength of the resin was higher or comparable to Bis-GMA/TEGDMA based resins (p > 0.05). The toughness (it was measured from the stress–strain curves of three-point bending test) of the resins was improved. Water sorption and water solubility tests showed that the hydrophobicity of resin was enhanced with increasing the content of thioester moiety in resin.

scholarly journals Effect of Glycero-(9,10-trioxolane)-trialeate on the Physicochemical Properties of Non-Woven Polylactic Acid Fiber Materials

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2517
Author(s):  
Anatoliy Olkhov ◽  
Olga Alexeeva ◽  
Marina Konstantinova ◽  
Vyacheslav Podmasterev ◽  
Polina Tyubaeva ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Polylactic Acid ◽  
Specific Surface Area ◽  
Water Sorption ◽  
Fiber Surface ◽  
High Water ◽  
Scanning Calorimetry ◽  
Fiber Mats ◽  
Fiber Materials

Biocompatible glycero (9,10-trioxolane) trioleate (ozonide of oleic acid triglyceride, OTOA) was incorporated into polylactic acid (PLA) fibers by electrospinning and nonwoven PLA mats with 1%, 3% and 5% OTOA content. The morphological, mechanical, thermal and water sorption properties of electrospun PLA mats after the addition of OTOA were studied. A morphological analysis showed that the addition of OTOA increased the average fiber diameter and induced the formation of pores on the fiber surface, leading to an increase in the specific surface area for OTOA-modified PLA fibrous mats. PLA fiber mats with 3% OTOA content were characterized by a highly porous surface morphology, an increased specific surface area and high-water sorption. Differential scanning calorimetry (DSC) was used to analyze the thermal properties of the fibrous PLA mats. The glass transition temperatures of the fibers from the PLA–OTOA composites decreased as the OTOA content increased, which was attributed to the plasticizing effect of OTOA. DSC results showed that OTOA aided the PLA amorphization process, thus reducing the crystallinity of the obtained nonwoven PLA–OTOA materials. An analysis of the mechanical properties showed that the tensile strength of electrospun PLA mats was improved by the addition of OTOA. Additionally, fibrous PLA mats with 3% OTOA content showed increased elasticity compared to the pristine PLA material. The obtained porous PLA electrospun fibers with the optimal 3% OTOA content have the potential for various biomedical applications such as drug delivery and in tissue engineering.

scholarly journals Comparison of Mechanical Properties of PMMA Disks for Digitally Designed Dentures

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Water Sorption ◽  
Water Solubility ◽  
Flexural Modulus ◽  
Manufacturing Method ◽  
Heat Curing ◽  
Significant Difference ◽  
Cad Cam ◽  
Curing Method

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

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