The Synthesis And Application Of Phosphite Antioxidants

With the development and wide use of polymer materials, developing novel antioxidant with high efficiency and environment friendly characters has been a frontier research topic in the field of polymer additives.In this dissertation, four new antioxidants of bis-(2, 4-di-tert-butylphenyl)phenylenephosphite ester (P1), bis-(2, 4-di-cumylphenyl) phenylenephosphite ester (P2),diphenylene-(2, 4-di-tert-butylphenyl) phosphite ester (P3) and diphenylene-(2,4-di-cumylphenyl) phosphite ester (P4) were synthesized by reaction of benzylphosphine dichloride (BPD) and diphenylphosphine chloride (DPC) with 2, 4-di-tertiary-butyl phenol and 2, 4-di-cumyI, respectively. Reaction factors such as reactants addition method, reaction temperature, reaction time, reactants ratio, drop time and the dosage of solvent used were investigated. All target compounds were characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR and MS.The hydrolytic stability and thermal stability of the four target compounds were investigated. It was found that, P1, P3, P4 are suitable for materials with processing temperature between 200-220 ?, while P2 can be used at processing temperature as high as 300 ?.The antioxidant performance of the four target compounds using as secondary antioxidants for PP during multiple extrusions was studied in combination with phenolic antioxidant AO-1010. And three widely used commercialized products (2,4-di-tert-butylphenyl) phosphite (AO-168), bis-(2, 4-di-tert-butylphenyl-4, 4'-biphenyl)diphosphite (P-EPQ), di-(2, 4-di-cumylphenyl) pentaerythritoldiphosphite (s9228) were also investigated for comparison. The performance was evaluated through study of the melt flow index (MFI) and yellowness index (YI) after five twin-screw extrusions, Long-term heat ageing (LTHA) and oxidation induction time(OIT) under 210 of modified PP.Evaluation of the antioxidant efficiency of the antioxidant system by melt index (MFI)and yellowing index (YI) after five twin-screw extrusions, the aging embrittlement time(LTHA) of first extrusion of the sample, as well as oxidation induction time(OIT) under 210?. The results showed that, P1, P2, P3 and P4 all showed better antioxidant performance than AO-168. The performance of P1 is comparable with P-EPQ and S9228, especially in the thermal process stability and anti-colour characters. The antioxidant mechanism were also proposed.