Study On Wet Spinning Of Silica Modified Phenolic Fiber

Phenolic fiber is a kind of high performance fiber,with excellent flame retardant,corrosion resistance,smokeless and non-toxic,outstanding mechanical properties.It is widely used in textile,transportation,aviation and other fields.After carbonization and activation,the original form of the fibers can be maintained.The activated carbon fibers prepared by activation and carbonization also have certain applications in the field of adsorption.In the process of producing phenolic fiber by wet spinning,there are some disadvantages,such as difficulty in spinning,high cost of curing and great pollution,which limit its industrial production and application.So to improve spinnability and properties of phenolic fiber becomes the key point of research.CO₂ activation can effectively avoid the pollution caused by chemical activation and reduce the cost when preparing active carbon fibers.In this paper,by introducing silicon into phenolic molecular structure through copolymerization,by changing the content of phenolic modifier and curing conditions,the best performance of silicon modified phenolic fiber（Si PF）was prepared.Then it was carbonized at high temperature and activated by carbon dioxide to prepare phenolic activated carbon fibers with better comprehensive properties.The research content of this paper is as follows:（1）The prepared silicon-modified phenolic resin is spun to prepare silicon-modified phenolic primary fiber,and then the silicon-modified phenolic fiber（Si PF）was finally obtained through thermal curing.The effects of phenolic ratio,modifier dosage,solidification bath condition,curing temperature and curing time on the properties of fibers were studied by FTIR,TG,DSC and mechanical properties.Finally,when the phenolic ratio,modifier dosage,coagulation bath temperature,boric acid concentration in the solidtfication bath,the thermal curing temperatue and the themal curing were1:1.5,5%,45%,3%,160℃and 40 min,respectively,the silicon modified phenolic fiber with excellent mechanical properties and heat resistance can be obtained.The breaking strength of the optimal Si PF was 196MPa with an elongation at break is 5.8%.The residual carbon content was 66.03%at 1000℃.（2）The Si PF with optimal mechancial property was carbonized at high temperature followed by carbon dioxide activion.The obtained carbon fiber was characterized by XRD and N₂ absorption-desorption measurements and thhe effects of carbonization temperature,activatin temperature and activation time on its adsorption peformance was also studied.Finally,it was founded that when the carbonization temperature was 800℃,the activation temperature was 700℃,and the activation time was 1.5h,the performance of activated carbon fiber was the best.At this time,the specific surface area of activated carbon fiber is 605 m²/g,the average pore diameter is 2.02 nm,the adsorption capacity of methylene blue is 221 mg/g,the adsorption capacity of iodine is 923 mg/g.