Melamine /ˈmɛləmiːn/ (About this soundlisten) is an organic compound with the formula C3H6N6. This white solid is a trimer of cyanamide, with a 1,3,5-triazine skeleton. Like cyanamide, it contains 67% nitrogen by mass, and its derivatives have fire retardant properties due to its release of nitrogen gas when burned or charred. Melamine can be combined with formaldehyde and other agents to produce melamine resins. Such resins are characteristically durable thermosetting plastic used in high pressure decorative laminates such as Formica, melamine dinnerware, laminate flooring, and dry erase boards. Melamine foam is used as insulation, soundproofing material and in polymeric cleaning products, such as Magic Eraser.
Melamine is sometimes illegally added to food products in order to increase the apparent protein content.[4] Ingestion of melamine may lead to reproductive damage, or bladder or kidney stones, and bladder cancer. It is also an irritant when inhaled or in contact with the skin or eyes. The United Nations' food standards body, the Codex Alimentarius Commission, has set the maximum amount of melamine allowed in powdered infant formula to 1 mg/kg and the amount of the chemical allowed in other foods and animal feed to 2.5 mg/kg. While not legally binding, the levels allow countries to ban importation of products with excessive levels of melamine.
Melamine is reported to have an oral median lethal dose (LD50) of 3248 mg/kg based on rat data. It is also an irritant when inhaled or in contact with the skin or eyes. The reported dermal LD50 is >1000 mg/kg for rabbits. A study by Soviet researchers in the 1980s suggested that melamine cyanurate, commonly used as a fire retardant,[21] could be more toxic than either melamine or cyanuric acid alone.[22] For rats and mice, the reported LD50 for melamine cyanurate was 4.1 g/kg (given inside the stomach) and 3.5 g/kg (via inhalation), compared to 6.0 and 4.3 g/kg for melamine and 7.7 and 3.4 g/kg for cyanuric acid, respectively.
Flame Retardant
A flame retardant melamine phosphate or fire retardant is a material that prevents fire or slows the spread of fire. Used in easy to burn materials as Plastics, Textiles or Coating.
Function of Flame Retardant
Absorb the burning heat to cool down the temperature and prevent polymer further decomposing.
Generate incombustible gas or foaming or liquid to cover the polymer surface to choke the burning.
Eliminate the radical.
Emit inert gas to dilute condensation of oxygen in burning area.
A toxicology study in animals conducted after recalls of contaminated pet food concluded that the combination of melamine and cyanuric acid in diet does lead to acute kidney injury in cats.[23] A 2008 study produced similar experimental results in rats and characterized the melamine and cyanuric acid in contaminated pet food from the 2007 outbreak.[24] A 2010 study from Lanzhou University attributed kidney failure in humans to uric acid stone accumulation after ingestion of melamine resulting in a rapid aggregation of metabolites such as cyanuric acid diamide (ammeline) and cyanuric acid.[25] A 2013 study demonstrated that melamine can be metabolized to cyanuric acid by gut bacteria. In particular, Klebsiella terrigena was determined to be a factor in melamine toxicity. In culture, K. terrigena was shown to convert melamine to cyanuric acid directly. Cyanuric acid was detected in the kidneys of rats administered melamine alone, and the concentration after Klebsiella colonization was increased
Different from the traditional silicone materials, which are not easily ignited, silicone thermoplastic
elastomer (Si-TPE) has poor flame retardant properties due to the existence of the hard segments in its
molecular chains. In this paper, melamine phosphate (MP), a kind of halogen free flame retardant, was
adopted to improve the flame retardancy of Si-TPE. The results showed that MP played the role of flame
retardant in both gas and condensed phases due to its nitrogen-phosphorus-containing structure. Inert
gases, including nitrogen, steam and ammonia which were released by the degradation of melamine
during burning, could take away the heat and dilute the oxygen in the gas phase, and further working
with the phosphoric acid, which was generated in the condensed phase, to form a denser and firmer
char layer. In this way, Si-TPE/MP composite with good flame retardancy was obtained. Interestingly, MP
had little influence on the thermal processability of Si-TPE, even at 28 wt% content, ascribing to its two
opposite effects on Si-TPE, but enhanced the comprehensive mechanical properties of Si-TPE with
suitable loadings, e.g. when the MP content was 28 wt%, the composite reached UL94-V0 rating, and its
tensile strength and Young's modulus were 3.5 MPa and 37.7 MPa, respectively.ynergetic enhancement on flame retardancy by melamine phosphate modified lignin in rice husk ash filled P34HB biocomposites
Lignin can be employed as a sustainable functional additive and reinforcement filler for polymers. In this work, melamine phosphate modified lignin (MAP-lignin) was synthesized as a bio-based halogen-free flame-retardant agent
1. Introduction
Silicone thermoplastic elastomer (Si-TPE) is a kind of synthetic
polymer consisting of a segmented structure of alternating so
blocks (organic silicon segments) that act as the elastic portion and
hard blocks melamine phosphate (plastic polymer segments) that act as the thermally
reversible cross-linking sites.1-3 This special structure endows SiTPE with not only the usual properties of silicone elastomers,
e.g. high and low temperature resistance, weather resistance,
superior corrosion resistance, low surface tension, small viscosity
and temperature coefficient, non-toxicity and good biocompatibility,4-9 but also the possibility of being thermally processed via
traditional plastic processing methods without chemical crosslinking, as well as controllable mechanical properties.10,11
The formation of the char barrier (Si-O, Si-C) at high
temperature is absolutely essential for the ame retardant
properties of a silicone material,12 but the introduction of the
hard blocks disturbs the regularity of Si-TPE molecular chains,
and decreases the proportion of silicone elements in it,
contrarily resulting in its worse ame retardancy and narrow
applications.13 To improve the ame retardancy of a silicone
material, various methods, mainly based on inorganic ame
retardants, have been adopted.12,14-16 However, these inorganic
ame retardants, e.g. Fe2O3, red phosphorus and platinum, are
commonly incompatible with the matrix, causing poor processability and mechanical properties as well as the dissatised
ame retardancy of the matrix. In recent years, researchers have
transferred their attentions to the organic ame retardants, e.g.
melamine, pentaerythritol, graphite, etc.,
4,17,18 but the large
additive content of organic ame retardants is usually required
to achieve the good ame retardancy, which not only deteriorates the processability and mechanical properties of the
materials, but also increases the cost.
Melamine phosphate (MP), a typical halogen-free phosphorus ame retardant, is the reaction product of melamine
and phosphoric acid, thus combining the ame retardancy of
both melamine and phosphoric acid. When burning, MP can
release phosphorus acids to carbonize and construct a stable
and dense charring barrier in the condensed phase to decrease
the ammability of a material,19 and nitrogen, bonded to the
triazine rings in MP, can also pass to the gaseous phase,20
further insulating the material from re. It has been reported
that phosphorous and silicone have synergistic ame retardancy,21-24 so MP has been widely used in some silicone contained materials to improve their ame retardancy. For
example, Li et al.25 adopted MP to promote the ame retardancy
of a,u-dihydroxy polydimethylsiloxane, and found that MP
could accelerate the thermal decomposition of this silicone
rubber to form oxygen and heat insulated barrier, thus effectively improving its limiting oxygen index.
a
Cite this: RSC Adv., 2018, 8, 5034
Received 29th November 2017
Accepted 22nd January 2018
DOI: 10.1039/c7ra12865g
rsc.li/rsc-advances
5034 | RSC Adv., 2018, 8, 5034-5041 This journal is © The Royal Society of Chemistry 2018
RSC Advances
PAPER
Open Access Article. Published on 29 January 2018. Downloaded on 7/18/2020 7:16:59 AM. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. View Article Online View Journal | View Issue
In our previous work,26 a novel Si-TPE consisting of urea
groups and the branched organic polysiloxane was developed.
This Si-TPE had quite good thermal processability and high
mechanical properties, but deteriorated ame retardancy due to
the existence of urea groups. Here, to improve the ame
retardancy of this novel Si-TPE, MP was adopted, and the effects
of MP content on the melt uidity, molecular structure, combusting process, char morphologies as well as mechanical
properties of Si-TPE were systematically studied, which would
surely extend the application elds of this novel Si-TPE
Melamin-fosfat
Eşanlamlılar triazin triamin fosfat; SLFR-7; MELAMİN FOSFAT; ÖZEL BİLEŞEN KE 8000; 1,3,5-Triazine-2,4,6-triamin, fosfat (1,3,5 :)
CAS Sicil No 41583-09-9
Moleküler formül C3H9N6O4P
Moleküler Ağırlık 224.12
EINECS 255-449-7
İntumesan Boya Girdileri ve İşlevleri
Intumesan boyalar ısı ya da aleve maruz kaldıklarında şişerek kabararak kalınlaşıp kömürümsü bir köpük tabakası oluşturarak
yüzeyin hava ısı ve ateş ile temasını engelleyip yanmayı yavaşlatan boyalardır. Ahşap, plastik veya çelik yüzeylerde uygulanabilirler.
Bu boyalar ısı ile 1 mm'den 10 cm'ye kadar yani kalınlıklarının 100 katı kadar şişebilirler. Yaklaşık 150-200˚C'de aktifleşip şişmeye
başlarlar.
İntumesan boya formüle etmek için 3 tip özel malzeme gereklidir:
1. Karbonifik: Karbon sağlayan malzeme, örneğin pentaerythritol veya nişasta gibi polioller. (Karbonifik malzemeler Perstorp'un
Charmor ürünlerinde bulunabilir.)
2. Asit oluşturucu malzeme: Örnekler ve bozunma sıcaklıkları:
• Amonyum polifosfat (215˚C),
• Monoamonyum fosfat (417˚C),
• Melamin fosfat (300˚C).
3. Spumifik: Gaz sağlayıcı malzeme. Örnekler ve bozunma sıcaklıkları:
• Üre (130˚C),
• Dicyandiamid (210˚C),
• Melamin (300˚C).