The Synthesis Of Phosphorus Containing Fire Retardants And The Study Of Fire Retarded Lyocell Fibres

There are many fire retardants that are suitable to cellulosic fibres and many of them are halogen containing compounds and among of them bromine compounds are usually the most effective fire retardants. However, the most usefull members of this class cause severe toxicological problems. Therefor , finding little toxic and non-halogen and high effective fire retardant compounds that are suitable to cellulosic fibres have confronted us all. With the increasing protective sense of eco-friendly, and the eco-friendly laws being settled down, the requirement of non-halgen and little smoke and high effective fire retardants becomes more and more urgent. A lot of new fire retardants that are non-halogen and little smoke and high effective have been born one by one. The new fire retardant compounds that are based on Phosphorus such as phosphorus-sulphur, phosphorus-nitrogen or phosphorus-oxygen containing compounds have been developed in the past decade years. Owing to their specific mechnism of flame resistant and the properties of non-halogen and little toxicity and little smoke , So, in recent years , the wide range of applicability of flame-retardant cellulosic fibres has drawn the attention of medical professionals, safety experts, insursnce companies and many consumer groups.In this paper, two major study works have been done:Firstly,the synthesis of phosphorus based fire retardants that are suitable to cellulosic fibres. It contains the synthesis of 1,2-bis (2-oxy-5, 5-dimethyl-1, 3, 2-dioxaphosphorinane-2, 2 -disulfide)(DDPS) ; and 1, 2-bis(2-oxy-5,5-dimethyl-l, 3, 2-dioxaphosphorinane phosphoryl amide) ethane (DDPN) ; and 1,2-bis(2-oxy-5,5-dimethyl-l, 3, 2-dioxaphosphorinane -2, 2 -disulfide phosphoryl amide) ethane (DDPSN) .Secondly, the study of fire retardant Lyocell fibres has been done. It contains the fabrication of Lyocell fibres and the study of the propertiesof the fire retardant Lyocell fibres.All the three fire retardants were identified by elemental analysis, TG-DTA, DSC, FTIR, 1HNMR, MS. In addition, the auther has optimized and studied the reaction routes and reaction conditions such as the selecting of optimum catalyst, slution, reaction time and reaction temperature. They are all resisted to acid and base.In this thesis,with the use of NMMO, the author studied the swelling , dissolving of the pulp in NMMO, filtering and removing bubles of the fabrication solution and the quality of pulpx the water percentage in NMMO, the density, temperature of fabrication solution the density of freezing bath, temperature, the length of air gap, the velocity of fabrication. With these work, the optimum fabrication parameters were found and fine Lyocell fibres were fabricated. The surface and section of Lyocell fibres were observed with the help of SEM.The fire resistant mechanism of fire retarded cellulosic membrane was studied by the use of TG-DAT and DSC. The result showes that the intumescent char formed under the pyrolysis of fire retardants can not only prevent outer air going into the membrane but also resist CO,CO2 releasing out of the membrane and discloses the condensed phase flame-retarding mechanism of phosphorus based fire retardants. SEM also shows that in the membrane matrix many porous are forming after the fire retarded cellulosic membrane flamed. It also shows that the phosphorus based fire retardants are working in the gas phase.The limiting oxygen index(LOI) of cellulosic membrane can rise from 19 to 29% when used the flame-retardant dope additive with the weight percentage 28%.Lyocell fibres was named the green fibres of the 21 century,but the fire retarded Lyocell fibres was few reported. The auther first successively fabricates fire retarded Lyocell fibres using the fire retardants which were synthesized, and the LOI of the fire retarded Lyocell fibres reachs 26. 5. Thesucessively of it will do great to cellulose industry.