Preparation Of Halogen-free Flame Retardant Pa6, Pp

In this paper, three halogen-free flame retardants were prepared and their application in the polymers materials was also studied. Modification of red phosphorus and alumina hydroxide were used by in-situ polymerization. The resulted retardants were encapsulated well by polymer film in order to improve their compatibility with polymer and stability, the effect of pH on encapsulation was also analyzed. Another retardant (layer-double hydroxide) was modified by one step coprecipitation through anion exchange to improve its hydrophobicity and thermal stability. Effects of reaction time, assisted intercalation agent as well as amount of intercalation agent were investigated.It was found that chemical modification had obvious effects on the topography and structure of resulted flame retardants, which were demonstrated by XRD, FT-IR, SEM and TEM. Furthermore, their thermal stabilities were characterized by TG and DSC analysis, and hydrophobicities were characterized by static contact angle.After preparation of three halogen-free flame retardants mentioned above, they were applied in polyamide 6 (PA6) and polyproplene (PP). First analyzed flame retardance effect of single retardant on polymer materials, followed by mutiply retardants mixed system in the form of orthogonal experiments. Inorganic filler retardants alumina hydroxide and layer-double hydroxide showed better compatibility with polymer materials and better effect of restraint smoke after chemical modification. The microencapsulated red phosphorus (MRP) presented an effective retardancy in PA6, vertical firing would rank UL94V-0 with 20 phr, but had much smoke. The studies revealed that when PA6:MRP: LDHs:ATH= 100 (phr):10 (phr):5 (phr):30 (phr), impact strength would come to 4.85 KJ/m2, improved by 19.5%; and the limited oxygen index (LOI) of the composite is 28.5 %, vertical firing ranking UL94V-0 (3.2 mm). As PP:MRP:LDHs:ATH= 100 (phr):10 (phr):15 (phr):30 (phr), the limited oxygen index (LOI) of the composite is 27.0%, vertical firing ranking UL94V-1 (3.2 mm). Besides, flexural strength of the composites were improved by 12.3%...