1. Principle of fabric combustion properties

(1) combustion phenomena can be divided into flame combustion and non-flame combustion. The former is the combustion of gas or volatile liquid formed during fiber pyrolysis, while the latter is the oxidation of residue (carbon).

(2) the combustion of fibers is related to the products of thermal cracking, and different fibers have different thermal cracking processes.

2. Mechanism of flame retardant

(1) cover theory:

Flame retardants in > 500 ℃ in the fiber surface form a blanket has isolation effect, in addition to hinder the supply of O2, also prevent flammable gas spread outward, so as to achieve purpose of flame retardant, such as borax and boric acid.

(2) gas theory:

1. Flame retardant decomposes non-flammable gas at the combustion temperature, dilutes the combustible gas concentration below the flame concentration that can be generated; 2. Under the heating condition, the flame retardant can be used as a highly active base transferer, thus preventing the free radical reaction.

(3) thermal theory:

1. The flame retardant changes, such as melting and sublimation, occur at high temperature to prevent the spread of combustion;

2. It is the rapid heat dissipation of the fiber that makes the fabric unable to reach the combustion temperature.

(4) catalytic dehydration theory:

It mainly refers to the process of thermal cracking that changes the fiber. The flame retardant can cause rapid and large amount of dehydration of cellulose molecular chains before fracture, and even some cross-linking action can prevent the formation of levo-glucose and inhibit flame combustion.

The flame retardant effect of organophosphorus compounds is due to its ability to form esters with hydroxyl in cellulose molecules, prevent the formation of l-glucose, further dehydrate cellulose to form unsaturated double bonds, promote the formation of cross-linking between cellulose molecules, increase the formation of carbon materials, and better anti-smouldering effect. Only when the amount of finishing agent is increased to 10% can the flame combustion be effectively prevented.

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