The Degradation Of PET To Synthesize Phosphate Flame Retardants And The Study Of Their Flame-retardant Performance

In recent years, because of good comprehensive performance, three synthetic materials and five synthetic resins faces the extensive development space, espeacially in textile materials, packaging, construction materials, electronic consumption, office and commodities, etc. However, these synthetic materials caused endless fire and caused a large number of casualties and property losses to the world. Then the global place more emphasies on security and environmental protection. As a result, flame retardant materials were paid much attention by the government agencies,producers and consumers. Therefore, green flame retardant agent with low smoke, non-halogen, low-toxic, high heat resistance is the goal for people to pursue and the synthesis and application of flame retardant in polymer composites become an important development trend.Polyphosphate flame retardants are a type of environment-friendly flame retardants with phosphorus and carbon as main elements. The carbon layer, decomposed by this type of flame retardants have the function of oxygen insulation , smoke suppression, preventation to produce melt drops, and have the advantage of good thermal stability, high volatile temperature, good compatibility resistance. Hence, they are more and more popular among people. Therefore, the development of polymerization phosphate flame retardant quickly become become a focus in the areas of flame retardants study.This topic is divided into four stages in total. In the first stage, Using chemical degradation method to recycle discarded PET polyester, which was then degradated to small ethylene glycol terephthalate. The process of technology is mature in this stage. In the second stage, Intermediate products TPC was synthesized using BHET and SOCl2, which was a acylating agent. Then TPC was characterized by IR spectrum, 1H-NMR spectrum and the optimum condition was determined with TPA3.32g(0.02mol),SOC127.4mL (0.1mol),catalyst 0.2g,temperature 80℃,time 4h. And the product yield is not less than 80%. In the third stage, several polyphosphate flame retardants with different proportions were synthesized by design synthetic routes and synthesis conditions optimization. And these polyphosphate flame retardants were characterized by IR spectrum and TGA analysis. At the same time, the materials rate, catalyst dosage, reaction temperature were respectively studyed by single factor method and the optimum condition was determined with n(TPC)/n(Na₃PO₄) = 1.8:1, the dosage of K₂CO₃ catalyst is 1.5% weight of Na₃PO₄, the reaction temperature was controlled in oil bath temperature around 105. At last, the flame retardancy finishing liquid was made of by these polyphosphate flame retardants. The flame retardancy finishing liquid was applied in cotton wovens to test and analyse their flame retardant property in breaking strength and heat stability by Vertical combustion method and oxygen index method. Then the optimum condition was determined with PFR300g/L, Na₂CO₃15g/L,osmotic agent and softener 5g/L,Curing temperature and time as 160℃×5 min或150℃×6 min. In this way, LOI value basically can reach 28% and the damaged length of cotton fabric does not exceed 12cm.The PET polymer as the initial material in this experiment is the main environmental pollution. However, PET polymer is recycled in the issue, not only protect environment, but make significant contribution in circular economy and resource utilization. This solution is the very innovation in choosing the material of polyphosphate flame retardants.