scholarly journals Synthesis and Properties of Peroxy Oligomers Obtained by Telomerization Effects of the Presence of Bases

2016 ◽  
Vol 5 (4) ◽  
pp. 261
Author(s):  
Michael M. Bratychak ◽  
Volodymyr B. Vostres ◽  
Marc J.M. Abadie
Keyword(s):  
Unsaturated Polyester ◽  
Diglycidyl Ether ◽  
Labile Hydrogen ◽  
Hydrogen Atoms ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Direct Titration ◽  
Mobile Hydrogen ◽  
One Step ◽  
Labile Hydrogen Atom

<p>New bifunctional oligomers bearing peroxy groups have been synthesized by telomerization in one step reaction. For obtaining oligoperoxides (PO) by telomerization method, epoxide compounds will react with substances containing labile hydrogen atom. Using the principle of stochiometric imbalance between diepoxy compounds and substances with mobile hydrogen atoms and employing a functional peroxide as telogen, the synthesis of PO was studied. 2,2–Di[4–(2,3–epoxy–1-propoxy)phenyl]–propane (diglycidyl ether of diphenylol propane - DGEDPP), 1,2–Di (2,3–epoxy–1-propoxy) ethane (diglycidyl ether of ethylene glycol - DGEEG) and 1,2–Epoxy–3–tert–butylperoxypropane (EP) have been synthesized by methods reported in the literature. Chemical structures have been confirmed by NMR and FTIR, number-average molecular weights M<sub>n</sub> of PO<sub>s</sub> by cryoscopy, active oxygen content [O]<sub>act</sub>. for PO<sub>s</sub> was determined by iodometry and epoxy number (<em>e.n</em>.) for PO<sub>s</sub> was measured via direct titration of PO samples. A 50% solution of potassium or sodium isopropylates in 2-propanol is used to catalyze the telomerisation. Different parameters such as ratio of components, temperature, reaction time have been optimized in vu to get well defined peroxy oligomers. The presence of peroxy groups in synthesized POs allows us to employ these compounds as curing agents for polymers containing unsaturated double bonds and may be used to improve performance of unsaturated polyester GFR systems.</p>

scholarly journals Synergistic interaction of renewable nipagin and eugenol for high performance aromatic copoly(ether ester) materials

2021 ◽  
Author(s):  
Keling Hu ◽  
Huachao Sui ◽  
Dongping Zhao
Keyword(s):  
High Performance ◽  
Synergistic Interaction ◽  
Differential Scanning Calorimetric ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Naturally Occurring ◽  
Ether Ester

Abstract Naturally occurring nipagin and eugenol were used as the collaborative starting materials for poly(ether ester) materials. In this study, two series of nipagin and eugenol-derived copoly(ether ester)s, PHN11-xE1x and PHN11-xE2x (x = 0%, 5%, 10%, 15%, 20%), were prepared with renewable 1,6-hexanediol as a comonomer. The nipagin-derived component acts as the renewable surrogate of petroleum-based dimethyl terephthalate (DMT), while the eugenol-derived component acts as the cooperative property modifier of parent homopoly(ether ester) PHN1. 1,6-Hexanediol was chosen as the spacer because of its renewability and short chain to enhance the glass transition temperatures (Tgs) of materials. The molecular weights and chemical structures were confirmed by gel permeation chromatograph (GPC), NMR and FTIR spectroscopies. Thermal and crystalline properties were studied by thermal gravimetric analysis (TGA), differential scanning calorimetric (DSC) and wide-angle X-ray diffraction (WXRD). The tensile assays were conducted to evaluate the mechanical properties. The results suggest that properties of such kind of poly(ether ester)s can be finely tuned by the relative content of two components. Synergistic interaction of two structurally distinctive parts endows the materials with high performance.

Synthesis and characterization of new, liquid, branched poly(methylvinylborosiloxanes)

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Jerzy Chruściel ◽  
Marzena Fejdyś ◽  
Witold Fortuniak
Keyword(s):  
Functional Groups ◽  
Atomic Spectroscopy ◽  
Size Exclusion ◽  
Random Structure ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Siloxane Oligomers ◽  
Exclusion Chromatography ◽  
Ether Solution

Abstract New liquid branched poly(methylvinylborosiloxanes) (br-PMVBS) of random structure were synthesized in three steps. By reacting boric acid with an excess of dimethyldichlorosilane (Me2SiCl2) in dry ether a “borosiloxane precursor”: tris(chlorodimethylsilyl) borate B(OSiMe2Cl)3 was prepared. In the second step of synthesis ether solution of B(OSiMe2Cl)3 was added to a mixture of appropriate organic chlorosilanes (Me2SiCl2, MeViSiCl2, MeSiCl3, and Me3SiCl) and all reagents were reacted with stoichiometric amounts of water, in the presence of pyridine (as an acceptor of HCl), in dry ether, at low temperature (usually at -10 to 0 C). In order to fully react (“to block”) trace silanol groups, reactions of intermediate PMVBS with additional batches of Me3SiCl were carried out in the third step, C5H5N·HCl was filtered off and washed with a dry ether. The solvent was distilled off from filtrates and low molecular weight siloxane oligomers were removed by a vacuum distillation at 130-150 C. Chemical structures of br-PMVBS were confirmed by elemental analysis and spectroscopic methods (FTIR, emission atomic spectroscopy ICP-AES, and NMR: 1H, 29Si and 11B). On the basis of analysis of their 29Si-NMR spectra the microstructure of polysiloxane chains was proposed. The prepared br-PMVBS had in their structures: triple branching borosiloxane units: BO1.5 and in some cases methylsiloxane moiety CH3SiO1.5 (T). They contained linkages: Si-O-Si, Si-O-B, vinyl(methyl)siloxane functional groups (CH2=CH)MeSiO (Dvi), dimethylsiloxane mers (CH3)2SiO (D), and non-reactive trimethylsiloxy terminal groups (CH3)3SiO0.5 (M), but they did not have: hydroxyl functional groups: Si-OH and B-OH, and sensitive to water B-O-B linkages. Molecular weights of br-PMVBS (Mn = 1500-3300 g/mol; Mw = 3800-7400 g/mol) and their polydispersity (Mw/Mn = 2.0-2.5) were determined by a size exclusion chromatography (SEC).

A Method For Rapid Visualization Of The Size- Distribution Of Factor VIII-Related Protein In Plasma

1981 ◽  
Author(s):  
B A Perret ◽  
R Felix ◽  
M Furlan ◽  
E A Beck
Keyword(s):  
Factor Viii ◽  
Size Distribution ◽  
Protein Pattern ◽  
Related Protein ◽  
Step Method ◽  
Silver Stain ◽  
Molecular Weights ◽  
One Step ◽  
Fresh Plasma ◽  
Normal Human

Factor VUI-related protein circulates in normal human plasma as a series of multimeric forms with apparent molecular weights ranging from 1 to 20×106. So far, combined electrophoretic and immunologic methods permitted demonstration of variable concentration and size- distribution of factor VIII-related protein in von Willebrand’s disease as compared to normal. We now have devised a one-step method for determining the size pattern of this plasma protein. Fresh plasma, containing 1% SDS and 0.8M urea, was layered on top of 2.5% polyacrylamide gels with 2.75% by weight of methylene bisacrylamide/acrylamide. Following extended electrophoresis in 0.2% SDS-0.1M Tris/HCl (pH 7.4), the gels were soaked in 5% formaldehyde and then extensively washed with 10% ethanol. Proteins were visualized employing an ultrasensitive ammoniacal silver stain. This staining revealed a multimeric protein pattern in the upper part of the gel the distribution of which was recorded by densitometry. The protein was identified as factor VIII by two-dimensional immunoelectrophoresis. The method was reproducible and allowed densitometric evaluation within 24 hr.

Effect of surface activation of alumina particles on the performances of thermosetting-based composite materials

2019 ◽  
Vol 53 (19) ◽  
pp. 2727-2742 ◽  
Author(s):  
Abdusalam Drah ◽  
Tihomir Kovačević ◽  
Jelena Rusmirović ◽  
Nataša Tomić ◽  
Saša Brzić ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyester Resin ◽  
Linseed Oil ◽  
Unsaturated Polyester ◽  
Surface Activation ◽  
Variable Amount ◽  
Multifunctional Composites ◽  
Alumina Particles ◽  
One Step ◽  
Effect Of Surface

Two types of alumina particles, commercial (c-Al2O3) and iron doped (Fe-Al2O3), were functionalized with 3-(aminopropyl)trimethoxysilane (one-step) and two-step consecutive process, i.e. firstly using 3-(aminopropyl)trimethoxysilane followed by methyl ester of linseed oil (biodiesel) to produce Al2O3ATPMS-BD reinforcement, respectively. The effect of modifier type and variable amount of alumina particles on the dynamical and mechanical properties of unsaturated polyester resin–based composites was studied. The highest improvement of the tensile strength and micro Vickers hardness, 78.1 and 163%, respectively, was obtained at 1.0 wt% of Fe-Al2O3APTMS-BD addition. The obtained multifunctional composites can be potentially applied in construction and mining industries.

Molecular Mechanism of Deformation in Epoxies – A Neutron Scattering Study

1986 ◽  
Vol 79 ◽  
Author(s):  
Wen-Li Wu
Keyword(s):  
Molecular Weight ◽  
Neutron Scattering ◽  
Molecular Mechanism ◽  
Bulk Material ◽  
Large Strain ◽  
Average Distance ◽  
Diglycidyl Ether ◽  
Molecular Weights ◽  
Scattering Study ◽  
Neutron Scattering Study

AbstractNeutron scattering was used to investigate the molecular mechanism of large strain deformation in epoxies. Partially deuterated diglycidyl ether of bisphenol A (DGEBA) was cured with either tri- or di-amines of different molecular weights. The change of the average distance between crosslinks along the epoxy and the amine linkages could easily be determined from the shift in the positions of the scattering maxima. It was found that the average distance between crosslinks remained almost unchanged along both the amine and the epoxy linkages as the bulk material underwent a large deformation. The above results are discussed in terms of the functionality of the junctions as well as the molecular weight between crosslinks. Comparisons are also made between the solid state deformation results and those from swollen networks which did show a substantial increase inaverage distance between crosslinks.

scholarly journals Investigation of Molecular Size Effect on the Formation of Lignin Nanoparticles by Nanoprecipitation

2020 ◽  
Vol 10 (14) ◽  
pp. 4910
Author(s):  
Jae Hoon Lee ◽  
Shin Young Park ◽  
In-Gyu Choi ◽  
Joon Weon Choi
Keyword(s):  
Polymeric Nanoparticles ◽  
Drug Carrier ◽  
Particle Surface ◽  
Molecular Size ◽  
Remarkable Change ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Potential Applications ◽  
Soda Lignin ◽  
Average Size

In recent years, several studies focused on the synthesis of lignin-based nanoparticle in aqueous solution and its potential applications of the drug carrier were investigated. In this study, soda lignin (SL) nanoparticles (i.d. 128–560 nm) were synthesized by the nanoprecipitation process at three different concentrations (1, 2, and 4 mg/mL THF) with various molecular sizes of soda lignin (NP-F1, NP-F2, and NP-F3) obtained from sequential solvent extraction. The average molecular weights of SL, F1, F2, F3, F4, and F5 were 3130, 1190, 2550, 3680, 5310, and 14,650, respectively. The average size of the spherical lignin nanoparticle was a minimum of 128 nm for NP-C1 and the size increased up to 560 nm with increasing concentration. Particle surface charge increased with increasing concentration from −26 mV for NP-C1 to −38 mV for NP-C4. Contrary to expected general trends in polymeric nanoparticles, there was no remarkable change or trend with increasing lignin molecular weight since chemical structures of each lignin fraction are also remarkably different. Further studies to learn correlation between properties of lignin nanoparticle and its additional details regarding the chemical structures is needed.

Synthesis and Properties of a High-Molecular-Weight Polyimide Based on 4, 4'-(hexafluoroisopropylidene) Diphthalic Anhydride

2012 ◽  
Vol 550-553 ◽  
pp. 742-746
Author(s):  
Hui Wen Wu ◽  
Hua Li ◽  
He Zhou Liu
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Organic Solvents ◽  
Membrane Separation ◽  
Amic Acid ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Synthesis Parameters ◽  
Soluble Polyimide

A soluble polyimide with high molecular weight was synthesized from 4, 4'-(hexafluoroiso propylidene) diphthalic anhydride (6FDA) and 2, 2’-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (BAPAF) via two-step polycondesation procedure involving the preparation of poly(amic acid) (PAA) followed by chemical imidization. Effect of synthesis parameters on polyimide molecular weight involving material ratio, imidization temperature and imidization catalyst were studied. Synthesized PI was analyzed with respect to their molecular weights, chemical structures and solubility through GPC, FTIR, XRD and solubility tests respectively. The results showed that a high-molecular-weight PI was successfully synthesized from 4, 4'-(hexafluoroisopropylidene) diphthalic anhydride and 2, 2’-bis (3-amino-4-hydroxyphenyl) hexafluoropropane with imidization at 80°C for 3h, material ratio of n(BAPAF):n(6FDA) equal to 1:1 and catalyst of n(triethylamine):n (pyridine) less than1:3. The obtained PI showed excellent solubility in polar aprotic organic solvents such as NMP, DMAc, DMSO, THF and Acetone. Poly(6FDA-BAPAF) PI, with high molecular weight and excellent solubility, which was synthesized under lower imidization temperature that was equal to 80°C,could be easily obtained and convenient to process, thus it is a potential material for membrane separation.

The non-isothermal oxidation of 2 -methylpentane. - III. The reaction at high pressure

1969 ◽  
Vol 313 (1513) ◽  
pp. 261-297 ◽  
Keyword(s):  
High Temperatures ◽  
Isothermal Oxidation ◽  
Gas Liquid Chromatography ◽  
Labile Hydrogen ◽  
Chain Process ◽  
Unimolecular Decomposition ◽  
Hydrogen Atoms ◽  
Radical Chain ◽  
Cool Flame ◽  
Alkylperoxy Radicals

The non-isothermal oxidation of 2-methylpentane has been studied at pressures of 1-4 MN m -2 and temperatures of 440 to 660 °C in an arrested-piston rapid-compression machine. The variations with pressure and temperature of the induction periods leading to cool-flame reaction and hot ignition have been determined, and the products of the reaction have been analysed by gas-liquid chromatography. At high temperatures and pressures the cool-flame reaction occurs by a free-radical chain process in which homogeneous isomerization and subsequent decomposition of alkylperoxy radicals propagate the chain. The resulting propa­gation cycle is substantially the same as that which has been established at lower tempera­tures and subatmospheric pressures. At high temperatures and pressures the reaction is, however, even more unselective, and oxidation of β -hydroperoxyalkyl radicals competes more successfully with their unimolecular decomposition, thus leading to the formation of β -ketoaldehydes. These compounds, together with the conjugated unsaturated carbonyl compounds, account quantitatively for the absorption of ultraviolet light by reacting 2-methylpentane/air mixtures. The mechanism of chain branching in the cool-flame reaction probably involves the pyrolysis of hydroperoxides. In the second stage of two-stage ignition, the propagation cycle is the same as that occurring in the cool flame but the important difference is that the cool flame has formed substantial concentrations of compounds with labile hydrogen atoms; these react readily with alkylperoxy radicals to form hydroperoxides, the pyrolysis of which again branches the chain.

Preparation and Characterization of Vanadium Pentoxide Hollow Microspheres with Tunable Sizes

2016 ◽  
Vol 697 ◽  
pp. 706-709
Author(s):  
Ming Gong ◽  
Chang An Wang
Keyword(s):  
Electron Microscopy ◽  
Solvothermal Method ◽  
Hollow Microspheres ◽  
Soft Template ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Weights ◽  
Transmission Electron ◽  
One Step

V2O5 hollow microspheres were synthesized by a one-step solvothermal method, with the assistance of PVP as the soft template, ethylene glycol (EG) as the solvent, and vanadium (iii) acetylacetonate (acac) as the metal-ions source. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM). The size of V2O5 hollow microspheres, which can be easily tuned by using PVP of different molecular weights, was about 2.5μm, 4.5μm and 6μm when using PVP-K17, PVP-K30 and PVP-K60 as the template, respectively.

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