Study On The Preparation And Flame Retardant Modification Of PPO/PA66 Alloy

PPO(Polyphenylene oxide)and PA66(Polyamide 66)are two kinds of wide-used engineering plastics. PPO has excellent physical and mechanical properties with deficiencies like low melt flow ability and poor process ability and poor solvent resistance, its product is easy to generate residual stress and stress cracking easily, these weaknesses seriously limit its application. Polyamide 66 has excellent melt flow ability and good solvent resistance, but its product possesses poor water resistance, these defects influence its range of application. So research the PPO/PA66 alloy is very valuable, on the one hand it can improve the poor process ablity and poor solvent resistance of PPO, on the other hand it also can improve the poor water resistance of PA66, in this case PPO and PA66 can realize the complementary advantages in performance and expand application scope at the same time. PPO is a nonflameable polymer, when it is melt blending with PA66, the flame retardant abilities of PPO/PA66 alloy is poor. It should improve its flame retardant by adding flame retardant. This thesis has two steps: firstly, PPO/PA66 alloy was prepared by adding a kind of compatilizer during melt blending process; secondly, then the flame retardant resistance of PPO/PA66 alloy was improved through adding several kinds of flame retardant. Finally a series of tests and analysis were done to those products of above two experiments.First, using the dicumyl peroxide(DCP) as the initiator, let high impact polystyrene(HIPS) and maleic anhydride(MAH) occur grafting reaction through melt mixed process to produce compatilizer HIPS-g-MAH; then PPO and PA66 and HIPS-g-MAH were melt mixed together to generate PPO/PA66 alloy. The optimum proportion was got by these tests of fourier transform infrared spectrometer, mechanical property, melt index, water absorption and SEM. Then the PPO/PA66 alloy was melt mixed with flame retardant to improve the flame retardant resistance ability. First, we added flame retardant organic montmorillonite(OMMT) to the alloy, the result showed that added a little OMMT can improve the mechanical property of the alloy, but the mechanical property will decrease with too many OMMT. The flame retardant property can be improved by adding OMMT, but it did not increase limit oxygen index(LOI) obviously. Second, we added flame retardant DBDPE/Sb2O3 to the alloy, we found that DBDPE/Sb2O3 can increase the flame retardant property obviously, but it had a big inmpact on the mechanical property of the alloy, with the proportion of Sb2O3 was more and more, the alloy,s mechanical property decreased more. At last, we took the compounded method to improve the flame retardant efficiency, it was founded out that OMMT was compounded with DBDPE/Sb2O3 could obviously improve the flame retardant effiency, compared with DBDPE/Sb2O3, it cost less and had less impact on the mechanical property of PPO/PA66 alloy. By compared these flame retardant methods, the best flame retardant system was that OMMT compounded with DBDPE/Sb2O3. The optimal mixed ration is OMMT/ DBDPE/Sb2O3=2:3:1.