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[塑料] 塑料阻燃深度总结(十二)阻燃剂的选择

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发表于 2013-10-20 09:10:32 | 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 />
1.3.3 阻燃剂的选择标准
55Criteria for the selection of flame retardants are usually based on:
●The efficiency of a particular type of flame retardant in a particular polymer
system
●The processing conditions of the polymer
●Compatibility and the ability to preserve valuable physical properties
● The cost – performance trade-off
通常,选用阻燃剂应考虑以下四个条件:
(1)    阻燃剂对聚合物的阻燃效率;
(2)    阻燃聚合物的加工工艺;
(3)    阻燃剂与基体的相容性以及对基体物理性能的影响;
(4)    性价比权衡。
56As mentioned above, halogenated flame retardants are more universal than phosphorus-based flame retardants because the halogenated retardants are effective primarily in the flame zone, which is chemically similar for many polymers. However, other criteria listed above require halogenated flame retardants to be tailored to specific polymers. For example , aliphatic halogenated flame retardants are used primarily in thermoset resins or in expandable polystyrene, because of their limited thermal stability. Flame retardants that are soluble in polystyrene are not good for HIPS, because solubility results in plasticization and a dramatic decrease in the heat distortion temperature. On the other hand, partially soluble additives (e.g., decabromodiphenyl oxide) are very suitable for HIPS because they help keep an acceptable heat distortion temperature and good impact properties. Although ABS is chemically similar to HIPS, additives that are soluble in polystyrene (e.g., tetrabromobisphe nol A or brominated epoxy oligomers) are
preferable. Because ABS has a higher rubber content than HIPS, the use of insoluble additives is detrimental for polymer toughness.
如前所述,由于卤系阻燃剂的气相阻燃作用十分高效且与大多数聚合物都有较好的相容性,故其比磷系阻燃剂更为通用。然而,上述其它选择标准就要求对不同的聚合物,应根据具体情况使用不同种类的卤系阻燃剂。例如,由于热稳定性较差,脂肪族卤系阻燃剂主要应用于热塑性树脂或发泡PS。与PS相容的阻燃剂不一定适用于HIPS,因为较好的相容性会致其发生塑化而导致热变形温度降低。与此相反,相容性相对较差的阻燃剂(如十溴二苯醚)则十分适用于HIPS,因其可保持HIPS较高的热变形温度与较好的抗冲击性。尽管ABS与HIPS结构相近,但其却更为适用与PS相容的阻燃剂(如四溴双酚A或溴化环氧树脂)。这是因为ABS的橡胶含量高于HIPS,使用不相容添加剂将导致材料韧性降低。
55Phosphorus-based flame retardants are usually more suitable for engineering plastics that undergo charring than for commodity polymers. In some plastics, such as PC – ABS or poly(phenylene oxide) – HIPS blends, phosphorus-based flame retardants are more effective then halogenated flame retardants. Antimony trioxide, which is a part of halogen-containing formulations, is a Lewis acid and may destabilize some condensation polymers. Furthermore, the impact properties of engineering polymers may suffer due to the presence of powdery antimony trioxide.

一般而言,磷系阻燃剂较适用于工程塑料,因为相比于日用品用高聚物,工程塑料可自成炭。在某些塑料中(如PC/ABS、PPO/HIPS共混物等),含磷阻燃剂比卤系阻燃剂更为高效。这是因为卤系阻燃系统中的协效剂Sb2O3是一种路易斯酸,可破坏一些聚合物的炭层。此外,氧化锑粉体将对工程塑料的抗冲击性带来不利影响。

翻译问题:①commodity polymers翻译为“日用品用高聚物”不妥,常翻译为“通用聚合物”②more effective then halogenated flame retardants中的then应该为than,是印刷错误。③Antimony trioxide, which is a part of halogen-containing formulations, is a Lewis acid and may destabilize some condensation polymers.这句话是说氧化锑破坏了某些缩聚物的稳定性,使缩聚物容易解聚。所以,原来翻译为“可破坏一些聚合物的炭层”,犯了扩大化的错误,尽管可能会破坏炭层,因为即使破坏聚合物也是我们所不需要的。

56Inorganic hydroxides are used at very high loading levels. Only certain polymers, e.g., polyolefins, can tolerate such high loading without a significant loss of physical properties. Furthermore, relatively low thermal stability, especially of ATH, significantly limits the use of inorganic hydroxides. Other polymeric systems in which ATH is used are PVC, unsaturated polyesters, and latex back-coatings of polyamide or polyester carpets

无机氢氧化物最为阻燃剂时,添加量极大。添加如此大量的填料后,仅有某些聚合物(如聚烯烃)仍能保持较好的物理性能。再者,相对较差的热稳定性(尤其是ATH)严重限制了无机氢氧化物的应用。目前,ATH主要应用于PVC、不饱和聚酯、PA背涂胶乳及聚酯地毯类材料。


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