Synthesis of Novel Halogen-Free Phenol Based Polymers and their utilization as Flame Retardant in Polypropylene system

2013 ◽  
Vol 1492 ◽  
pp. 161-166 ◽  
Author(s):  
Ruchi Bakshi ◽  
Sethumadhavan Ravichandran ◽  
Weeradech Kiratitanavit ◽  
Jayant Kumar ◽  
Ramaswamy Nagarajan
Keyword(s):  
High Performance ◽  
Flame Retardants ◽  
Radical Scavenging ◽  
Thermal Characterization ◽  
Free Phenol ◽  
New Class ◽  
Char Formation ◽  
New Varieties ◽  
Halogen Free ◽  
Halogenated Flame Retardants

ABSTRACTIncreasing awareness of toxicity of halogenated flame retardants (FRs) has resulted in stringent regulations that require the elimination of their use in plastics. Consequently, there is considerable interest for the development of new varieties of high performance FRs. Here, we report the synthesis of new class of polyphenol based FR additives. Preliminary investigations indicate that these FR materials can possibly work through a combination of radical scavenging and char-formation. The thermal stability and char yield of polyphenol samples were investigated by thermogravimetric analysis (TGA). Thermal characterization indicated that these polymers produce significant amount of carbonaceous char upon combustion.

Polyurethane flexible foam fire resisting by melamine and expandable graphite: Industrial approach

2011 ◽  
Vol 47 (6) ◽  
pp. 549-565 ◽  
Author(s):  
A Gharehbaghi ◽  
R Bashirzadeh ◽  
Z Ahmadi
Keyword(s):  
Physical Properties ◽  
Flame Retardants ◽  
Fire Behavior ◽  
Expandable Graphite ◽  
Fire Retardants ◽  
Safety Issues ◽  
Flexible Foam ◽  
Halogen Free ◽  
Phase Out ◽  
Halogenated Flame Retardants

According to importance of the safety issues especially in air industry, fire-resisted parts and interiors consumption are increasing. Seat foam has a huge fraction of the airplane interior and this makes it essential to become safer. From another point, planning to phase out some of the halogenated flame retardants because of persistence in the environment, bioaccumulation, and toxicity. In recent years, halogen-free fire retardants have been more investigated. In this work, we have concentrated more on two well-known, solid, halogen-free fire retardants, expandable graphite and melamine, and compared their performance according to their fire behavior, physical properties, and production phenomena.

Highly efficient halogen-free flame retardants of thermally-oxidized polyacrylonitrile copolymers containing bio-derived caffeic acid derivatives

2020 ◽  
Vol 11 (41) ◽  
pp. 6658-6669
Author(s):  
Jongho Kim ◽  
Nam-Ho You ◽  
Bon-Cheol Ku
Keyword(s):  
Caffeic Acid ◽  
High Performance ◽  
Flame Retardants ◽  
Caffeic Acid Derivatives ◽  
Highly Efficient ◽  
Halogen Free

Polyacrylonitrile (PAN) copolymer with catechol comonomer is utilized as a precursor for the production of high-performance flame retarding fibers and is also widely used for clothing fibers.

scholarly journals Recent Developments in the Flame-Retardant System of Epoxy Resin

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2145 ◽  
Author(s):  
Quanyi Liu ◽  
Donghui Wang ◽  
Zekun Li ◽  
Zhifa Li ◽  
Xiaoliang Peng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Flame Retardant ◽  
Epoxy Resin ◽  
Flame Retardancy ◽  
High Performance ◽  
Flame Retardants ◽  
Great Progress ◽  
Recent Developments ◽  
Halogen Free

With the increasing emphasis on environmental protection, the development of flame retardants for epoxy resin (EP) has tended to be non-toxic, efficient, multifunctional and systematic. Currently reported flame retardants have been capable of providing flame retardancy, heat resistance and thermal stability to EP. However, many aspects still need to be further improved. This paper reviews the development of EPs in halogen-free flame retardants, focusing on phosphorus flame retardants, carbon-based materials, silicon flame retardants, inorganic nanofillers, and metal-containing compounds. These flame retardants can be used on their own or in combination to achieve the desired results. The effects of these flame retardants on the thermal stability and flame retardancy of EPs were discussed. Despite the great progress on flame retardants for EP in recent years, further improvement of EP is needed to obtain numerous eco-friendly high-performance materials.

Conductive Filament Formation in Printed Circuit Boards – Effects of Reflow Conditions and Flame Retardants

2009 ◽  
Author(s):  
Bhanu Sood ◽  
Michael Pecht
Keyword(s):  
Flame Retardants ◽  
Printed Circuit Boards ◽  
Electrochemical Process ◽  
Lead Free ◽  
Circuit Boards ◽  
Filament Formation ◽  
Conductive Filament ◽  
Printed Circuit ◽  
Free Solder ◽  
Halogen Free

Abstract Failures in printed circuit boards account for a significant percentage of field returns in electronic products and systems. Conductive filament formation is an electrochemical process that requires the transport of a metal through or across a nonmetallic medium under the influence of an applied electric field. With the advent of lead-free initiatives, boards are being exposed to higher temperatures during lead-free solder processing. This can weaken the glass-fiber bonding, thus enhancing conductive filament formation. The effect of the inclusion of halogen-free flame retardants on conductive filament formation in printed circuit boards is also not completely understood. Previous studies, along with analysis and examinations conducted on printed circuit boards with failure sites that were due to conductive filament formation, have shown that the conductive path is typically formed along the delaminated fiber glass and epoxy resin interfaces. This paper is a result of a year-long study on the effects of reflow temperatures, halogen-free flame retardants, glass reinforcement weave style, and conductor spacing on times to failure due to conductive filament formation.

A trait collection of spring groat barley

2018 ◽  
pp. 85-96
Author(s):  
I.A. Petukhova ◽  
V.K. Riabchun ◽  
V.A. Muzapharova ◽  
O.I. Padalka ◽  
T.A. Sheliakina ◽  
...  
Keyword(s):  
High Performance ◽  
Spring Barley ◽  
Vegetation Period ◽  
Grain Weight ◽  
Starting Material ◽  
Economic Traits ◽  
The Czech Republic ◽  
Science And Education ◽  
New Varieties ◽  
1000 Grain Weight

The goal of our research was to form a collection of groats barley, to search, to select and to evaluate starting material of spring barley for a set of valuable economic traits, technological properties and culinary qualities of barley groats. Results and Discussion. Basing on to the results of assessments, we identified selected 55 spring barley accessions, which were characterized by 17 traits and 75 expression levels. The collection includes accessions from 11 countries; the largest number of accessions (59) are from Ukraine; 39 – from Russia; 10 - from Belarus; 10 - from Germany; 6 - from France; 5 - from Kazakhstan; 4 - from Canada; 3 - from the Czech Republic; 2 – from Great Britain; 1 accesson is from Serbia; and 1 - from Austria. Accessions combining high levels of expression of different traits are the most valuable. They include the following accessions: Doridnyi, Vodohrai, Sviatomykhailivskyi, Svarozhych, Soka, Іlot (UKR). Naked accessions include: Akhilles (UKR), Mayskiy, Oskar, Golozyornyy 1, Omskiy Golozyornyy 1 (RUS), CDC Alamo, CDC Candle (CAN). These varieties can be starting material for creation of new modern high-performance spring groats barley varieties. Ten valuable accessions registered with the NCPGRU (Sovіra, Doridnyi, Soka, Vodohrai, Partner, Yukatan, Avhii, Svarozhych, Baskak, and Virtuoz) were included in the trait groats collection. Conclusions. Basing on the results of multiyear studies, we formed the trait collection of spring groats barley comprising 140 accessions from 11 countries. The collection includes 55 reference accessions that cover 17 traits (plant height, vegetation period, ear length, grain weight per ear, 1000-grain weight, grain shape, grain evenness, vitreousness, culinary qualities of barley groats, etc.) characterized by 75 levels of their expression. The collection is of considerable value for science and education. The accessions selected allow improving the efficiency of breeding to create new varieties with high technological and culinary properties as well as with a set of valuable economic characteristics.

New Class of Trimetallic Oxide Hierarchical Mesoporous Array on Woven Fabric: Electrode for high-Performance and Stable battery type Ultracapacitor

2021 ◽  
Vol 35 ◽  
pp. 102249
Author(s):  
S. Thakur ◽  
S. Maiti ◽  
K. Sardar ◽  
N. Besra ◽  
P. Bairi ◽  
...  
Keyword(s):  
High Performance ◽  
Woven Fabric ◽  
New Class

High performance inkjet-printed QLEDs with 18.3% EQE: improving interfacial contact by novel halogen-free binary solvent system

Nano Research ◽  
2021 ◽  
Author(s):  
Ming Chen ◽  
Liming Xie ◽  
Changting Wei ◽  
Yuan-Qiu-Qiang Yi ◽  
Xiaolian Chen ◽  
...  
Keyword(s):  
High Performance ◽  
Solvent System ◽  
Binary Solvent ◽  
Interfacial Contact ◽  
Halogen Free

scholarly journals (−)-Epicatechin—An Important Contributor to the Antioxidant Activity of Japanese Knotweed Rhizome Bark Extract as Determined by Antioxidant Activity-Guided Fractionation

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 133
Author(s):  
Urška Jug ◽  
Katerina Naumoska ◽  
Irena Vovk
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
High Performance ◽  
Radical Scavenging ◽  
Size Exclusion ◽  
Solvent Mixtures ◽  
Japanese Knotweed ◽  
Compound Identification ◽  
Rp Hplc ◽  
Ic50 Value

The antioxidant activities of Japanese knotweed rhizome bark extracts, prepared with eight different solvents or solvent mixtures (water, methanol, 80% methanol(aq), acetone, 70% acetone(aq), ethanol, 70% ethanol(aq), and 90% ethyl acetate(aq)), were determined using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. Low half maximal inhibitory concentration (IC50) values (2.632–3.720 µg mL−1) for all the extracts were in the range of the IC50 value of the known antioxidant ascorbic acid at t0 (3.115 µg mL−1). Due to the highest extraction yield (~44%), 70% ethanol(aq) was selected for the preparation of the extract for further investigations. The IC50 value calculated for its antioxidant activity remained stable for at least 14 days, while the IC50 of ascorbic acid increased over time. The stability study showed that the container material was of great importance for the light-protected storage of the ascorbic acid(aq) solution in a refrigerator. Size exclusion–high-performance liquid chromatography (SEC-HPLC)–UV and reversed phase (RP)-HPLC-UV coupled with multistage mass spectrometry (MSn) were developed for fractionation of the 70% ethanol(aq) extract and for further compound identification, respectively. In the most potent antioxidant SEC fraction, determined using an on-line post-column SEC-HPLC-DPPH assay, epicatechin, resveratrol malonyl hexoside, and its in-source fragments (resveratrol and resveratrol acetyl hexoside) were tentatively identified by RP-HPLC-MSn. Moreover, epicatechin was additionally confirmed by two orthogonal methods, SEC-HPLC-UV and high-performance thin-layer chromatography (HPTLC) coupled with densitometry. Finally, the latter technique enabled the identification of (−)-epicatechin. (−)-Epicatechin demonstrated potent and stable time-dependent antioxidant activity (IC50 value ~1.5 µg mL−1) for at least 14 days.

scholarly journals Environmentally Friendly, High-Performance Fire Retardant Made from Cellulose and Graphite

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2400
Author(s):  
Leandra P. Santos ◽  
Douglas S. da Silva ◽  
Thais H. Morari ◽  
Fernando Galembeck
Keyword(s):  
High Performance ◽  
Raw Materials ◽  
Fire Retardant ◽  
Visual Observation ◽  
Flame Resistance ◽  
New Developments ◽  
New Class ◽  
New Material ◽  
Accredited Laboratory ◽  
Materials Used

Many materials and additives perform well as fire retardants and suppressants, but there is an ever-growing list of unfulfilled demands requiring new developments. This work explores the outstanding dispersant and adhesive performances of cellulose to create a new effective fire-retardant: exfoliated and reassembled graphite (ERG). This is a new 2D polyfunctional material formed by drying aqueous dispersions of graphite and cellulose on wood, canvas, and other lignocellulosic materials, thus producing adherent layers that reduce the damage caused by a flame to the substrates. Visual observation, thermal images and surface temperature measurements reveal fast heat transfer away from the flamed spots, suppressing flare formation. Pinewood coated with ERG underwent standard flame resistance tests in an accredited laboratory, reaching the highest possible class for combustible substrates. The fire-retardant performance of ERG derives from its thermal stability in air and from its ability to transfer heat to the environment, by conduction and radiation. This new material may thus lead a new class of flame-retardant coatings based on a hitherto unexplored mechanism for fire retardation and showing several technical advantages: the precursor dispersions are water-based, the raw materials used are commodities, and the production process can be performed on commonly used equipment with minimal waste.

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