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[塑料] 塑料阻燃深度总结(七)三聚氰胺阻燃剂

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发表于 2013-10-20 09:24:43 | 显示全部楼层 |阅读模式
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本帖最后由 846082533 于 2015-12-31 14:59 编辑 <br /><br />
1.3.2.3 三聚氰胺阻燃剂
36、Melamine is a unique product with 67wt% nitrogen in the molecule and fairly high thermal stability. Melamine also forms thermally stable salts with strong acids. Melamine itself, melamine cyanurate, melamine phosphate, melamine pyrophosphate, and melamine polyphosphate are commercially available for various flame retardant applications. The
mechanism of flame retardant action of melamine is different from the mechanism of melamine salts or may be part of the mechanism of action of the salts. In addition, melamine phosphates have specific advantages because of the presence of phosphorus in the molecule.
三聚氰胺(MA)是一种独特的化合物,含氮量高达67%,且具有相当优异的热稳定性,也可与强酸反应生成热稳定性很好的盐。三聚氰胺(MA)、三聚氰胺氰脲酸盐(MCA)、三聚氰胺磷酸盐(MP)、三聚氰胺焦磷酸盐(MPP)及三聚氰胺聚磷酸盐(MPP,有点混淆)均可作为具有多功能应用的工业阻燃剂。MA的阻燃作用机理不同于MA盐类,也可认为前者后者的一部分。此外,三聚氰胺磷酸盐因含磷而具有独特优异的性能。
37、Upon heating, to whatever extent it does not sublime away, melamine can undergo progressive condensation with evolution of ammonia and formation of thermally stable condensates, known as melam,  melem, and melon. This reaction competes with melamine volatilization and is more pronounced if the volatilization of melamine is impeded: for example, by trapping in the charred polymer. Formation of the residue is considered to be a condensed-phase contribution of melamine, whereas ammonia evolution dilutes the flame with noncombustible gases.
升温时,三聚氰胺极难升华,可发生“氨解”并在凝聚相形成稳定性很好的产物(蜜白胺、蜜勒胺、氰尿酰胺)。该反应与其挥发机理背道而驰,挥发越少(如炭层阻碍挥发时),则该反应效果越明显。成炭作用是MA的凝聚相作用机理,而“氨解”作用可生成难燃气体从而有效发挥气相阻燃作用。
38Upon heating, melamine-based salts dissociate, and re-formed melamine volatilizes in a manner similar to pure melamine. However, in the case of melamine salts, a larger portion of melamine under goes progressive condensation than does pure melamine; therefore, the condensed-phase contribution of the salts is larger. If the anion contains phosphorus, the phosphoric acid released will phosphorylate many polymers and produce a flame retardant effect similar to that of other typical phosphorus-based additives (see above). Melamine condensates and phosphoric acid react further at temperatures above 600?C, where triazine rings are opened and cross-linked. A (PON)x type of structure known as phosphorus oxynitride is formed. Phosphorus oxynitride is very thermally stable and in some polymers can contribute to condensed-phase mechanisms.

升温时,三聚氰胺盐可热解并重新生成MA,后者可类似于单一MA而挥发。然而相对于纯MA,三聚氰胺盐生成的MA成炭率更高;因此,MA盐类主要发挥凝聚相作用。若与含磷阻燃剂复配使用,后者生成的磷酸也可使聚合物磷酸化,从而发挥与其它典型含磷阻燃剂相同的阻燃作用(见上述)。当高于600℃时,MA凝聚相可与磷酸发生反应,三嗪环开环交联形成(PO)x型结构的含磷氮氧化物,后者热稳定性极好,在一些聚合物中可发挥凝聚相阻燃作用。

翻译问题:If the anion contains phosphorus的意思是“如果三聚氰胺盐的阴离子基团含磷(元素)。“若与含磷阻燃剂复配使用”翻译不准确,因为复配是combination,是外加的,类似与掺混,而原文的意思是“内含”。

39Melamine cyanurate is used primarily in unfilled polyamides. Upon thermal decomposition, melamine is partially volatilized, whereas cyanuric acid catalyzes chain scission of polyamides. This leads to a decrease in melt viscosity and enhanced melt flow and dripping, which removes heat from the polymer and the polymer is extinguished. The vaporizing melamine probably prevents drips from flaming. The fire retardant effect of melamine cyanurate deteriorates significantly in glass-filled polyamides because glass fibers prevent free melt flow.

现在MC主要应用于未填充聚酰胺。热分解时MA部分挥发,氰尿酸可催化PA发生断链。这导致PA的熔体粘度降低,促进了熔融滴落,从而有效带走了热量并致其自熄。挥发性的MA可有效抑制熔滴的产生。玻璃纤维对熔体的流动有阻碍作用,故MC应用于玻纤增强PA时其阻燃效率大打折扣。

翻译问题:The vaporizing melamine probably prevents drips from flaming.这句的准确翻译应该为:挥发的三聚氰胺可能会妨碍燃烧产生熔滴(因为挥发带走了热量,熔滴就少了)。这个句子是从概率角度推测一个结论,而不是语气很强的一个推断。翻译者使用“可有效抑制”,给人的感觉好像是很肯定的语气,这与前面的“这导致PA的熔体粘度降低,促进了熔融滴落,从而有效带走了热量并致其自熄”的结论,看起来很矛盾。事实上,MA只是部分挥发,大部分进入凝聚相,所以,挥发性的MA只是可能妨碍熔滴的产生而已。

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