Study On Preparation Of Modiifed Melamine-formaldehyde Fiber

As a kind of high performance flame retardant fiber, melamine fiber has been widelyused in the fabric of flame retardant、high temperature resistance filter material and so on.The melamine formaldehyde resin (MF) is a kind of thermosetting resin with threedimensional network structure, and it has poor toughness, which greatly limited thedevelopment of melamine fiber. In order to improve the performance of melamine fiber, alot of research at home and abroad has been carried on the blending spinning of MF andpolyvinyl alcohol (PVA), but by now still no achievement has been made onindustrialization. In this work, two kinds of blending fibers were prepared through theblending modification and electrostatic spinning of MF-PVA and MF-PAN in order toexpand its application scope.The melamine formaldehyde resin has been firstly prepared according to differentprocess conditions, and then MF was blended with PVA and PAN respectively. The effecton electro-spinning rule of the viscosity of spinning solution, spinning voltage andspinning distance has been studied via determination of viscosity and electrostaticspinning.The result of synthetic process showed that the most suitable conditions of synthesisof melamine resin was pH9, the melamine and formaldehyde mole ratio1:1.7, reactingtemperature80℃,reacting time1.5h. The limited oxygen index test showed that: the LOIof melamine resin itself was32with excellent flame-retardant property.The blending modification experiments of MF and PVA revealed that the mostsuitable viscosity range to perform electrostatic spinning was150mpa·s~250mpa·s (testedat70℃) with12wt%PVA added and the solid content ratio of MF and PVA was at1:1.The spinning distance was settled at5cm under spinning voltage at20kV. At this point, theelectrostatic spinning effect was the best, and the LOI of MF-PVA fiber was about28withexcellent flame retardant performance.When the PAN concentration in the PAN-DMF solution was about10%~12%and theMF resin accounted for15%~20%of PAN, the spinning effect was the best. However, theLOI of the MF-PAN blending fiber was only about23.5. When the addition of MF wasincreased to40%of the mass of PAN, the limited oxygen index was26.5. The samples were detected by SEM, XRD, FTIR and the LOI Test. SEMobservation results showed that the uniformity of MF-PVA and MF-PAN blending fiber isquite good, it proved that MF and PVA or MF and PAN have a good blending performance.FTIR analysis showed that effective flame retardant structure elements such as the aminogroups and triazine ring are present in MF-PVA and MF-PAN fibers, which lead to goodflame retardant performance to the blending fiber. XRD analysis showed that comparedwith PVA and PAN fiber, the crystallization ability of both MF-PVA and MF-PANdecreased, which is beneficial to improve the flexibility and performance of the blendingfiber.The results above showed that the blending preparation of MF-PAN fiber is feasibleby comparison, and the spinning effect is better than that of MF-PVA fiber. In a word, theblending preparation of melamine resin and PAN has great significance and potentialbusiness development.