Study On The Cyclization And Pre-oxidation Of Acrylic Fibre To Manufacture A Flame-retardant Fibre

As an intermediate product, the pre-oxidized PAN fiber occupies an important place in the production of carbon fiber. The productive technology of pre-oxidized PAN fiber companies with the development of carbon fiber. At the same time, for its special flame-retardant property, pre-oxidized PAN fiber also can be used as a textile fiber to produce special clothing, decorate material, and high-temperature filter materials used in the fields of high-temperature and flam-retardant. But the application of pre-oxidized PAN fiber in those fileds is quite rare, not to mention the pre-oxidation of civil acrylic fiber. For this reason, it is very important to launch studies on the pre-oxidation technology and application of civil acrylic fiber, which will take an important role to promote its development in China.To obtain the pre-oxidized fiber with good textile properties and flame-retardant property, the civil acrylic fiber is first pre-cyclized chemically and then pre-oxidized in this paper. The study synopsis includes:Selection of reagent for chemical and cyclization pre-treatment. The effect of surface-treatment of civil acrylic fiber on the structure and properties of pre-oxidized PAN fiber(PANOF)which is treated by single reagent of hydroxylamine, cyclization reagent and copper sulfate separately and by two-different reagents is studied. The result indicates that the structure and properties of PANOF could be improved by hydroxylamine-cyclization reagent two-step pre-treatment. So the hydroxylamine-cyclization reagent two-step pre-treatment of civil acrylic fiber is selected in this paper.Study on the process of pre-treament.The influence of pre-treatment condition on the structure and properties of PANOF is studied, using the above selected hydroxylamine-cyclization reagent two-step pre-treament. The result shows that high-property PANOF can be acquired following the pre-treatment conditions:concentration of hydroxylamine is 3%, concentration of CuCl is 0.3%, concentration of sodium carbonate is 0.8%, temperature of hydroxylamine solution is 80℃,reaction time is 10min, concentration of cyclization reagent is 3%, temperature of cyclization reagent solution is 80℃, reaction time is 10min, the mass-volume ratio of solution is 1:10.Study on the process of pre-oxidization. The pre-oxidization process is studied. The result indicates that the PANOF with proper mechanical and flame-retardant properties, which meets the demand of textile flame-retardant fibre, can be acquired at the speed of temperature-rising 10℃/10min with the highest pre-oxidization temperature 260℃.Study on the mechanism of pre-treament. The amine-oxime reaction, mechanism of Cu+-cyanogen complexation, mechanism of cyclization reagent-Cu+-cyanogen cyclization are studied. The heat-property and chemical cyclization-degree of pre-treated acrylic fiber have been characterized by infrared spectrometer, DTA and TG analyses. The principle of property-improve of PANOF is explained,which is brought about by the particular functional groups after pre-treatment process.