Synthesis, Formulation And Application Of Isocyanate Modified Polyether Silicone Oil For Carbon Fiber Precursor Acrylic Fiber

Polyether modified silicone oil is a kind of commonly used auxiliary agents in the formulated oil agent for carbon fiber precursor acrylic fiber,but there exist several major concerns about polyether modified silicone oil such as too high percentage of silicone,difficult synthesis and complicated purification process,therefore in this master thesis,I developed the technology of self-assembly to modify the structure of polyether modified silicone oil so that series of self-emulsifying and particle size controllable auxiliary agents are prepared.Finally I formulated the isocyanate modified polyether silicone oil with other chemically modified silicone oil such as epoxy modified silicone oil,hydroxyl amino modified silicone and other additives,studied the properties of formulated oil agents,applied them to carbon fiber precursor acrylic fiber,carried out oxidizing at 200 to 400?in airatmosphere and carbonizing the bundle at 1000?,or higher in an inert atmosphere to produce the carbon fibers,and tested the final product of carbon fiber.?1?In the first section,octadecyclosiloxane?D₄?was used as the raw material,and 1,1,3,3-tetramethyldisiloxane?HMM?as the end-capping reagent to prepare hydrogen-terminated silicone oil called as hydrogenated silicone oil by using the concentrated sulfuric acid as a catalyst.The hydroxyethoxypropyl terminated silicone oil was prepared by hydrosilylation method with the hydrogenated silicone oil and ethylene glycol monallyl ether at catalytic amount of hexchloroplatinicacid.A large number of parallel experiments have been completed and the optimizable experimental conditions to synthesize isocyanate polyether modified silicone oil reached that the mole ratio of hydrogenated silicone oil and ethylene glycol monallyl ether is 1:1.1,reaction temperature is at 100?,the reaction time is 6 h and the amount of hexachloroplatinic acid was 30?g per gram of total reacting reagents.The product structure was determined by FT-IR spectra and ¹H NMR.?2?In the second section,A self-emulsifiable anionic polyurethane modified polyether silicone oil emulsion was prepared by using hydroxyethoxypropyl silicone oil,polypropylene glycol,2,2-dimethylolpropionic acid,toluene-diisocyanate?TDI?as raw materials,ethylenediamine as a chain extension agent,and triethylamine as a neutralizing agent.The synthesized product is tested by FT-IR spectra to determine product structure.The effect of content and molecular weight of hydrophilic polypropylene glycol and hydrophobic hydroxyethoxypropyl silicone oil on emulsion properties was discussed,a conclusion was drawn when the content of the hydrophilic group is increased,the particle diameter of the emulsion is decreasing and the surface tension is becoming lower;but when the content of the hydroxyethoxypropyl silicone oil is increasing or the molecular weight of the hydroxyethoxypropyl silicone oil is increasing,the particle diameter of the emulsion is becoming larger,the heat resistance is enhanced,and the surface tension is increased.?3?In the third section,a self-emulsifiable nonionic isocyanate modified polyether silicone oil emulsion was prepared by using hydroxyethoxypropyl silicone oil,hexamethylene diisocyanate and allyl polyether?APEG?as raw materials.The reacting product was monitored by FT-IR spectra.The effect of molecular weight of hydroxyethoxypropyl silicone oil and APEG on emulsion properties was discussed,a conclusion was drawn that APEG is of the certain molecular weight,the molecular weight of polyether silicone oil increases,the particle size of the emulsion increases,the heat resistance is enhanced,and the molecular weight of polyether silicone oil is1500,the surface tension is the lowest;but hydroxyethoxypropyl silicone oil is of the certain molecular weight,and the larger the molecular weight of APEG,the smaller the particle size of the emulsion and the higher the heat resistance are becoming.Due to little change of the molecular weight,so the surface tension is almost unchanged.When the molecular weight of APEG is 700,the molecular weight of the hydroxyethoxypropyl silicone oil is preferably less than 3,000 so that the emulsion has good storage stability.?4?In the last Section,oil agents are formulated by selecting the right silicone oil and additives:?1?Polyurethane modified polyether silicone oil is formulated with side chain polyether modified silicone oil,when the content of the side chain polyether modified silicone oil is increasing,the emulsion stability is good,the particle diameter is increasing,the heat resistance is enhanced,and the surface tension is decreasing.?2?Isocyanate modified polyether silicone oil is formulated with epoxy modified silicone oil,emulsion stability is good,when the molecular weight of the polyether modified silicone oil is 1000,the particle size of the formulated silicone oil is larger than that of epoxy modified silicone oil self-emulsified emuslion,and the surface tension becomes larger,when the molecular weight of the polyether modified silicone is 1500,the particle size does not change much and the surface tension becomes the lowest,when the molecular weight of the polyether modified silicone oil is becoming larger,the particle size and surface tension of emulsion is increasing.The heat resistance of the formulated oil agent is increasing with the molecular weight of the modified polyether silicone oil.The carbon fiber was produced and evaluated after the PAN fiber was coated by the oil agent and performed pre-oxidizing at 200-300?and carbonization at 300-700?and 1000?or higher temperature,the performance of the formulated oil agent can basically reach the standard of Japanese bamboo oil.