Research On Synthesis Of P-N Synergistic Hyperbranched Flame Retardant Loaded By Metal Ion And Its Application In Modification Of General Thermoplastic Polymer

Flame retardant modification of polymer materials has important significance in the prevention of fire and reduceing fire hazards,and it has become one of the key research fields of polymer materials.The melt-blending method is the most commonly applied,but adding flame retardants have many problems such as small molecular weight,high addition amount and poor compatibility with polymer matrix,etc.The development of environmental protection,low toxicity,high efficiency,multi function flame retardant has become the future development trend of flame retardant industry.To solve the above problem,a kind of P-N synergistic hyperbranched flame retardant with high molecular weight and rich groups was prepared by combining hyperbranched polymer,P-N synergistic flame retardant and synergistic effect of metal ions with high efficiency and low toxicity,designed and prepared rich carboxyl terminated hyperbranched P-N synergistic flame retardant,and further through metal ion complexation crosslinking,obtained hyperbranched P-N-Zn²⁺synergistic flame retardant,the structure and properties of the two flame retardants were characterized and analyzed,further the flame retardant composites(PET,PA6 and PP)were prepared and the structure and properties of the composites were studied.The main content and the corresponding results were summarized as follows:1)3-hydroxyphenylphosphinyl-propanoic acid and 1,3,5-tris(2-hydroxyethyl)cyan-uric acid were used as raw material to synthesize P-N synergistic hyperbranched flame retardant CT with high molecular weight and rich groups,then modified by Zn²⁺to improve the flame retardant efficiency and prepare P-N-Zn²⁺synergistic hyperbranched flame retardant CT-Zn²⁺to solve the problem of low melting point.The test results of CT showed that weight-average molecular weight is 43000g/mol,the melting point is 79.86?,the phosphorus content is 10.22 wt%,the nitrogen content is 5.89 wt%,the T_5%value is 317.5?.The test results of CT-Zn²⁺showed that CT-Zn²⁺is a non melting substance,the phosphorus content is 8.47 wt%,the nitrogen content is4.94 wt%,the zinc content is 10.25 wt%,the T_5%value is 381.9?,CT-Zn²⁺is more thermal stable than CT.Melt behavior and thermal stability of modified CT-Zn²⁺all have been changed and promoted as expected.2)The test results of PET/CT and PET/CT-Zn²⁺composite resins showed that adding small amount of CT(3.9 wt%)and CT-Zn²⁺(7.1 wt%)promoted the crystallization of PET,CT and CT-Zn²⁺improved the thermal stability,char-forming ability and the rheological property of PET.Dispersion tests showed that CT and CT-Zn²⁺can be evenly dispersed in the PET matrix.When the phosphorus content of composite resins improved from 0 ppm to 9000 ppm,the LOI values of PET/CT and PET/CT-Zn²⁺composite resins improved from 21.7%to 33.8%and 35.4%,UL-94 all reached to V-0 grade(molten drop does not ignite cotton),AHRR was reduced by 52.2%and61.3%,respectively,and THR decreased by 24.2%and 29.7%,respectively.In the case of the same phosphorus content,CT-Zn²⁺has better flame retardant effect than CT,flame retardant effect truthful statement.Spinning process of PET/CT and PET/CT-Zn²⁺composite fibers with 6000ppm phosphorus content showed that,under the condition of not optimized spinning process,all of the conditions are good.3)The test results of PA6/CT-Zn²⁺composites showed that adding small amount of CT-Zn²⁺(7.1 wt%)promoted the crystallization of PA6,CT-Zn²⁺improved the thermal stability,char-forming ability and the rheological property of PA6.Dispersion tests showed that CT-Zn²⁺can be evenly dispersed in the PA6 matrix.Spinning process of PA6/CT-Zn²⁺composite fibers with 4000 ppm phosphorus content showed that,under the condition of not optimized spinning process,all of the conditions are good.4)The test results of PP/CT and PP/CT-Zn²⁺composites showed that CT and CT-Zn²⁺promoted the crystallization of PP,but CT and CT-Zn²⁺have poor dispersion in PP matrix.Rheological properties test results showed that CT increase the viscosity of PP,and CT-Zn²⁺reduce the viscosity of PP.