| Polyamide 6(PA6)is one of the most common and most widely used polyamide materials.Its excellent comprehensive properties are the main reason why PA6 has tremendous application as engineering plastics and synthetic fibers.However,PA6 has a series of problems such as flammability,easy dripping,rapid flame diffusion,and large heat and smoke release during combustion under high temperature environment,among which the key problem is its low flame retardance.It not only limits the application of PA6 in electrical and electronic environment,but also severely limits the application in military clothing,fire-fighting clothing,public fabric decoration and other fields with high requirements for flame retardancyIn this paper,two series of copolymerized flame retardant PA6(c-PA 6)resins with relatively high limited oxygen index were prepared.At the same time,they were applied in fiber and composite materials to obtain fabrics and composites with good flame retardancy.The main research work is as follows1.A diacarboxylic acid monomer(DPPATPO)with high content of flame retardant elements was synthesized by combining the structure of triazine benzene ring with 2-carboxyethyl phenylhypophosphonic acid.The structure characterizations carried out by means of IR,1H NMR and elemental analysis showed that DPPATOP was successfully synthesized and had the potential to be used in melt polycondensation of PA6 under high temperature.2.DDP or DPPATPO were chosen as the second monomers and used in random copolymerization with caprolactam and hexanediamine to synthesize DDP based and DPPATPO based c-PA6 resins.Series reactions were carried out and the optimum reactant formula was selected.3.The DDP or DPPATPO based two series of c-PA6 synthetic products were spun and made into fabric.Compared with the traditional flame retardant finishing for fabric,flame-retardant fabrics made of c-PA6 had obvious advantages in flame-retardancy.On the other hand,compared with DPPATPO(2.4%loading)based c-PA6 fabric,DDP(the same loading)based c-PA6 fabric had good spinnability with little filament floating phenomenon,and the latter had better damage length and limited oxygen index than the former.4.c-PA6 and glass fiber(GF)(c-PA6/GF)and blending flame retardant PA6(b-PA6)(b-PA6/GF)fibers were prepared and the comparative research between them were carried out.The effects of different GF kinds,contents and processing aids on the properties of c-PA6/GF composites were studied.The thermal stability,crystallization,mechanical properties,flame retardancy and cross-section morphology of the two composites were also investigated.The results showed that the composite has when flat GF was used and the content reached 30%with silicone masterbatch as a process aid,the composites had the best comprehensive properties and excellent thermal stability.Although their combustion grade could reach V-0,DPPATPO based C-PA6/GF materials had higher limited oxygen index and ignition temperature. |
