Preparation And Aluminizing Process Of Aramid 1313/ Polyimide/flame Retardant Polyester Spunlaced Felt

Fire suit is an important protective equipment in the process of fire fighting and rescue,especially the heat insulation layer,which is of great significance to improve the thermal protection effect of fire suit.At present,the heat insulation layer of fire suit is mainly made of high performance fibers such as aramid 1313 and aramid 1414,which are processed by needling or spunlacing.Polyimide fiber has the advantages of flame retardancy and good thermal stability,so it has been widely used in the surface fabric of fire protection clothing,but it has not been applied in the insulation layer.This theis is to take the fire suit insulation layer as the research object,to further improve its flame retardant performance and thermal protection performance,to provide more efficient protection for firefighters.In this theis,aramid 1313,polyimide and flame retardant polyester were used as raw materials to make spunlaced felt,the optimal fiber ratio and aluminizing processing were discussed,and then the influence of coating method on the performance of spunlaced felt were also involved.The three kinds of fibers were tested firstly in this thesis.The results show that polyimide fiber has the best tensile strength,friction coefficient,flame retardant and heat resistance among the fibers,which has the limit oxygen index as high as 44%,so it is the best suitable fiber for insulation material that can effectively improve the strength of heat insulation and flame retardant.In addition,it can also be mixed with aramid 1313 and flame retardant polyester fiber.Aramid 1313 has moisture recovery rate up to 5.22%,so it has good moisture absorption and can fully absorb the water needle energy in the process of spunlacing,so as to improving fiber entanglement reinforcement.Flame-retardant polyester is the coarsest fiber among the three fibers,which can serve as a skeleton structure to improve the uniformity of the mesh and reduce the production cost.Then,using aramid 1313 as material,single factor analysis was used to study the influence of different spunlacing parameters on the entanglement coefficient of aramid spunlaced felt.The study shows that with the increase of spunlacing pressure and times,the entanglement coefficient of spunlaced felt gradually increased,but the increase range gradually decreased.The entanglement coefficient of spunlaced felt decreases with the increase of transfer curtain speed.After that,9 kinds of heat insulation samples with different fiber ratios were prepared with aramidon 1313,polyimide and flame retardant polyester by the optimum spunlacing process,and their mechanical properties,gas permeability,thermal stability,flame retardant and thermal insulation properties were tested and analyzed.The results show that the gas permeability of each sample is good and can meet the requirements of users.With the increase of polyimide content,the performance of insulation layer is improved.With the increase of the content of flame retardant polyester,the mechanical properties,thermal stability,flame retardant and thermal protection properties of the samples basically decreased,but the thermal resistance first increased and then decreased.The comprehensive comparison shows that when the ratio of polyimide/aramid 1313/ flame retardant polyester is 50/40/10,the comprehensive performance of the insulation layer is the best.Finally,this paper studies the aluminizing process of the sample prepared with the best spunlacing process.The single-side aluminizing is carried out by point-adhesion coating and brush-coating.The results show that the thermal stability of the brush-coated sample is improved,while the thermal stability of the point-adhesion coating sample is slightly decreased.However,the limiting oxygen index and longitudinal and transverse damage length of aluminized samples were improved,and the thermal protection performance(TPP value)was significantly improved.TPP values of the two aluminized samples were respectively increased by 43.7% and 54.1% compared with the original samples,which was because aluminum has good flame retardant and thermal radiation reflection function.The research in this thesis provides good alternative for improving the thermal protection effect of fire suit.