scholarly journals Synthesis and Polymerization of Naphthoxazines Containing Furan Groups: An Approach to Novel Biobased and Flame-Resistant Thermosets

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Davi Rabelo de Oliveira ◽  
Selma Elaine Mazzetto ◽  
Diego Lomonaco
Keyword(s):  
High Performance ◽  
Thermal Analyses ◽  
Polymeric Materials ◽  
Single Step ◽  
Polymerization Temperature ◽  
Flame Resistance ◽  
Biobased Materials ◽  
H Nmr ◽  
Chemical Structures ◽  
Nmr Techniques

Naphthoxazines are a class of compounds with potential application in obtaining high-performance polymeric materials. Such application of these compounds, however, is still scarcely explored in the literature. Combined with the search for new high-performance materials, the development of biobased polymers has gained a lot of attention. In this sense, the inclusion of furan groups in polymers has been explored as a strategy that combines the search for high-performance materials with the search for the development of biobased materials. In this work, novel naphthoxazine monomers containing furan groups were synthetized. The syntheses were carried out in a single step, without the use of solvents and catalysts, obtaining the products in satisfactory yields and high purity. The naphthoxazines had their chemical structures completely characterized by FTIR, 1H NMR, and 13C NMR techniques. The thermal analyses (DSC and TGA) showed that all naphthoxazines exhibit exothermic typical polymerization events, making these compounds suitable for obtention of poly(naphthoxazines) resins, but suffer significant mass losses at temperatures below the onset polymerization temperature. In this way, a catalyst (1 mol% MgCl2) was used in order to allow the polymerization of the compounds before the mass loss events. The FTIR analysis showed strong evidences of the formation of poly(naphthoxazines), and TGA analyses showed that the resins have high thermal stability, with high flame resistance and self-extinguishing properties (LOI > 28), which makes these compounds attractive in the development of biobased and high-performance materials.

Six-Sided Heptaporphyrin Array: Towards a Nano-Sized Cube

2004 ◽  
Vol 69 (5) ◽  
pp. 996-1008 ◽  
Author(s):  
Steven J. Langford ◽  
Clint P. Woodward
Keyword(s):  
Single Step ◽  
One Pot ◽  
H Nmr ◽  
The Core ◽  
Nmr Techniques ◽  
Axial Vertex

A strategy in preparing a family of hexameric porphyrin cubes based on the interplay of Sn(IV)-O and Ru(II)-N interactions is described. In this first iteration, we have prepared the heptamer [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 (4 = (E)-(3-(4-pyridyl)acrylate)) constituting a 5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) core and 5,10,15,20-tetraphenylporphyrin (TPP) faces and compared its formation by stepwise and "one-pot" strategies where up to nine components are assembled in a single step in a regiospecific manner. In one example, the heptamer is formed around the template [SnIV(TPyP)·(4)2] bearing pyridine groups in which the nitrogens radiate octahedrally along each vertex. The ability to modulate the axial vertex through choice of pyridine is also demonstrated. 1H NMR measurements on [SnIV(TPyP)·(4)2][Ru(CO)(TPP)]6 indicate that the protons on the core template are extremely shielded as a result of the anisotropy of the peripheral porphyrin units. Various NMR techniques, including NOESY experiments, have been used to characterise the heptamer in solution.

scholarly journals Design of High-Performance Polybenzoxazines with Tunable Extended Networks Based on Resveratrol and Allyl Functional Benzoxazine

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2794
Author(s):  
Yunliang Xing ◽  
Xianru He ◽  
Rui Yang ◽  
Kan Zhang ◽  
Shengfu Yang
Keyword(s):  
High Performance ◽  
Condensation Reaction ◽  
Good Thermal Stability ◽  
Chemical Structures ◽  
Dsc Measurements ◽  
Mannich Condensation ◽  
Polymerization Behavior ◽  
Oxazine Ring ◽  
Nmr Techniques ◽  
Ft Ir

A novel resveratrol-based bio-benzoxazine monomer (RES-al) containing an allyl group has been synthesized using resveratrol, allylamine, and paraformaldehyde via Mannich condensation reaction, and its chemical structures have been characterized by FT-IR spectroscopy and NMR techniques. The polymerization behavior of this benzoxazine resin has been investigated using in situ FT-IR and differential scanning calorimeter (DSC) measurements, and the thermal-mechanical properties of its corresponding polybenzoxazines are evaluated by DMA and TGA. We show that by controlling the curing process of the oxazine ring, the C=C bond in resveratrol, and the allyl group in RES-al, the cross-linking network of the polybenzoxazine can be manipulated, giving rise to tunable performance of thermosets. As all curable functionalities in RES-al are polymerized, the resulted polybenzoxazine exhibits a good thermal stability with a Tg temperature of 313 °C, a Td5 value of 352 °C, and char yield of 53% at 800 °C under N2.

scholarly journals Efficient and mild synthesis of pyrano-pyrimidines catalyzed by decorated multi-walled carbon nanotubes bearing cobalt, nickel and copper metals in water

2021 ◽  
Author(s):  
Nasrin Saberi Harouni ◽  
Hossein Naeimi
Keyword(s):  
Reaction Times ◽  
Single Step ◽  
High Yield ◽  
One Pot ◽  
H Nmr ◽  
Multi Walled Carbon Nanotubes ◽  
Nmr Techniques ◽  
One Step ◽  
Ft Ir ◽  
Walled Carbon Nanotubes

Abstract Multicomponent reactions are reactions in which three or more are agreeable of raw interests, composed in a one-step chemical process and the product is formed they give. Since multivariate reactions are monovalent reactions and Single-step conversions to ideal synthesis are very close. In this research, one pot three components reaction was carried out between 1, 3-dimethylbarbituric acid, malononitrile and different aldehydes in the attendance of Cu/Co/Ni/MWCNTs as a recyclable catalyst. This catalyst indicated high catalytic actuality with good proficiency and reusable under mild reservation. This reaction is performed fine at ambient temperature. This method proposed numerous materials such as being environmentally amicable for short reaction times and creating high yield products. The catalysts were collected and specified with diversity spectroscopic, such as techniques, such as FT-IR, X-ray fracture, and scanning electron microscopy. After finalization of the reaction, the vintage was obsolete, purified and identified by the melting points, infrared spectroscopy (FT-IR) and the magnetic resonance of the hydrogen nucleus (1H NMR) techniques.

scholarly journals Analysis by RP-HPLC and Purification by RP-SPE of the C-Tetra(p-hydroxyphenyl)resorcinolarene Crown and Chair Stereoisomers

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Alver A. Castillo-Aguirre ◽  
Zuly Jenny Rivera Monroy ◽  
Mauricio Maldonado
Keyword(s):  
High Performance ◽  
Solid Phase ◽  
Reverse Phase ◽  
Formation Reaction ◽  
H Nmr ◽  
Rp Hplc ◽  
Cyclocondensation Reaction ◽  
Nmr Techniques ◽  
Ft Ir ◽  
C Nmr

A method for the separation of stereoisomer mixture of the octol C-tetra(p-hydroxyphenyl)calix[4]resorcinarene that was obtained by an acid cyclocondensation reaction between resorcinol and benzaldehyde is reported in this paper. A crude product from octol formation reaction was analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC), and two well-resolved signals corresponding to the crown and chair isomers were found. A reverse phase in solid-phase extraction (RP-SPE) protocol allowed the separation of the two stereoisomers with high purity of each isomer. Finally, the crude and purified stereoisomers were characterized by using FT-IR, 1H-NMR, and 13C-NMR techniques, confirming the chemical identity of the two isomers and the efficiency in the separation process.

The Effects of Coupling Agent on the Flame Retardant Properties of PP/ATH Nanocomposites

2015 ◽  
Vol 1115 ◽  
pp. 406-409 ◽  
Author(s):  
Fatimah A’thiyah Sabaruddin ◽  
Noorasikin Samat ◽  
A.I.H Dayang Habibah
Keyword(s):  
Flame Retardant ◽  
Flame Retardancy ◽  
Coupling Agent ◽  
Oxygen Index ◽  
Polymeric Materials ◽  
Coupling Agents ◽  
Flame Resistance ◽  
Limiting Oxygen Index ◽  
Chemical Structures ◽  
Flame Retardant Properties

It is known that polymeric materials are easily to get on fire due to their chemical structures. Thus the flame retardant material such as aluminium hydroxide (ATH) is used to improve the flame retardancy property of polymers. Polypropylene (PP) with various amount of nanosized ATH particles of (5, 10, 20, 30, 40 wt%) were compounded with an extruder machine. The effects of two different type of coupling agent (3-Aminopropyltriethoxysilane (APS) and Maleic anhydride grafted polypropylene (MAPP)) on the flame retardant properties were compared. All samples were characterized with two flame tests; the limiting oxygen index (LOI) and UL94 horizontal burning test (UL94 HB). It is found that both tests showed improvement on the flame resistance properties of the nanocomposites, mainly at high ATH loadings. Type of coupling agents affects the flame retardancy properties of PP/ATH nanocomposites.

A Recommender System for Inverse Design of Polycarbonates and Polyesters

2020 ◽  
Author(s):  
Nathaniel Park ◽  
Dmitry Yu. Zubarev ◽  
James L. Hedrick ◽  
Vivien Kiyek ◽  
Christiaan Corbet ◽  
...  
Keyword(s):  
Ring Opening ◽  
High Performance ◽  
Recommendation System ◽  
Polymeric Materials ◽  
Monomer Conversion ◽  
Design Strategy ◽  
Ring Opening Polymerization ◽  
Inverse Design ◽  
False Negatives ◽  
Accelerate Development

The convergence of artificial intelligence and machine learning with material science holds significant promise to rapidly accelerate development timelines of new high-performance polymeric materials. Within this context, we report an inverse design strategy for polycarbonate and polyester discovery based on a recommendation system that proposes polymerization experiments that are likely to produce materials with targeted properties. Following recommendations of the system driven by the historical ring-opening polymerization results, we carried out experiments targeting specific ranges of monomer conversion and dispersity of the polymers obtained from cyclic lactones and carbonates. The results of the experiments were in close agreement with the recommendation targets with few false negatives or positives obtained for each class.<br>

scholarly journals Mechanochemical synthesis of poly(trimethylene carbonate)s: an example of rate acceleration

2019 ◽  
Vol 15 ◽  
pp. 963-970 ◽  
Author(s):  
Sora Park ◽  
Jeung Gon Kim
Keyword(s):  
Ball Milling ◽  
Mechanochemical Synthesis ◽  
Polymeric Materials ◽  
Solvent Free ◽  
Energy Output ◽  
Polymerization Temperature ◽  
Mechanical Degradation ◽  
Trimethylene Carbonate ◽  
Rate Acceleration ◽  
Conventional Solution

Mechanochemical polymerization is a rapidly growing area and a number of polymeric materials can now be obtained through green mechanochemical synthesis. In addition to the general merits of mechanochemistry, such as being solvent-free and resulting in high conversions, we herein explore rate acceleration under ball-milling conditions while the conventional solution-state synthesis suffer from low reactivity. The solvent-free mechanochemical polymerization of trimethylene carbonate using the organocatalysts 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) are examined herein. The polymerizations under ball-milling conditions exhibited significant rate enhancements compared to polymerizations in solution. A number of milling parameters were evaluated for the ball-milling polymerization. Temperature increases due to ball collisions and exothermic energy output did not affect the polymerization rate significantly and the initial mixing speed was important for chain-length control. Liquid-assisted grinding was applied for the synthesis of high molecular weight polymers, but it failed to protect the polymer chain from mechanical degradation.

Azo (Hydrazone) pigments: general principles

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Christie
Keyword(s):  
High Performance ◽  
Metal Salt ◽  
Low Cost ◽  
Cost Effective ◽  
Precipitation Process ◽  
Ambient Temperatures ◽  
Technical Performance ◽  
Chemical Structures ◽  
General Chemical ◽  
Physical Form

Abstract This paper presents an overview of the general chemical principles underlying the structures, synthesis and technical performance of azo pigments, the dominant chemical class of industrial organic pigments in the yellow, orange, and red shade areas, both numerically and in terms of tonnage manufactured. A description of the most significant historical features in this group of pigments is provided, starting from the discovery of the chemistry on which azo colorants are based by Griess in the mid-nineteenth century, through the commercial introduction of the most important classical azo pigments in the early twentieth century, including products known as the Hansa Yellows, β-naphthol reds, including metal salt pigments, and the diarylide yellows and oranges, to the development in the 1950s and 1960s of two classes of azo pigments that exhibit high performance, disazo condensation pigments and benzimidazolone-based azo pigments. A feature that complicates the description of the chemical structures of azo pigments is that they exist in the solid state as the ketohydrazone rather than the hydroxyazo form, in which they have been traditionally been illustrated. Numerous structural studies conducted over the years on an extensive range of azo pigments have demonstrated this feature. In this text, they are referred to throughout as azo (hydrazone) pigments. Since a common synthetic procedure is used in the manufacture of virtually all azo (hydrazone) pigments, this is discussed in some detail, including practical aspects. The procedure brings together two organic components as the fundamental starting materials, a diazo component and a coupling component. An important reason for the dominance of azo (hydrazone) pigments is that they are highly cost-effective. The syntheses generally involve low cost, commodity organic starting materials and are carried out in water as the reaction solvent, which offers obvious economic and environmental advantages. The versatility of the approach means that an immense number of products may be prepared, so that they have been adapted structurally to meet the requirements of many applications. On an industrial scale, the processes are straightforward, making use of simple, multi-purpose chemical plant. Azo pigments may be produced in virtually quantitative yields and the processes are carried out at or below ambient temperatures, thus presenting low energy requirements. Finally, provided that careful control of the reaction conditions is maintained, azo pigments may be prepared directly by an aqueous precipitation process that can optimise physical form, with control of particle size distribution, crystalline structure, and surface character. The applications of azo pigments are outlined, with more detail reserved for subsequent papers on individual products.

Star-shaped arylacetylene resins derived from silicon

2020 ◽  
Vol 40 (8) ◽  
pp. 676-684
Author(s):  
Niping Dai ◽  
Junkun Tang ◽  
Manping Ma ◽  
Xiaotian Liu ◽  
Chuan Li ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Mechanical Test ◽  
Flexural Modulus ◽  
Mechanical Analysis ◽  
Reinforced Composites ◽  
Scanning Calorimetry ◽  
Chemical Structures ◽  
Structures And Properties ◽  
High Performance Resin

AbstractStar-shaped arylacetylene resins, tris(3-ethynyl-phenylethynyl)methylsilane, tris(3-ethynyl-phenylethynyl) phenylsilane, and tris (3-ethynyl-phenylethynyl) silane (TEPHS), were synthesized through Grignard reaction between 1,3-diethynylbenzene and three types of trichlorinated silanes. The chemical structures and properties of the resins were characterized by means of nuclear magnetic resonance, fourier-transform infrared spectroscopy, Haake torque rheomoter, differential scanning calorimetry, dynamic mechanical analysis, mechanical test, and thermogravimetric analysis. The results show that the melt viscosity at 120 °C is lower than 150 mPa⋅s, and the processing windows are as wide as 60 °C for the resins. The resins cure at the temperature as low as 150 °C. The good processabilities make the resins to be suitable for resin transfer molding. The cured resins exhibit high flexural modulus and excellent heat-resistance. The flexural modulus of the cured TEPHS at room temperature arrives at as high as 10.9 GPa. Its temperature of 5% weight loss (Td5) is up to 697 °C in nitrogen. The resins show the potential for application in fiber-reinforced composites as high-performance resin in the field of aviation and aerospace.

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