Preparation And Interfacial Properties Of Glass Fiber Reinforced Polyurethane Composite Fibers

Glass fiber reinforced resin composite is a representative textile reinforced composite material,which is widely used in the fields of aerospace,automotive technology,medical devices,and new energy.It is mainly composed of glass fiber reinforcing phase,resin matrix phase,and interfacial phase,but as the properties between the glass fibers and the resin matrix are quite different,it is difficult to form a stable and strong interfacial phase between them.For composite materials,the stability and strength of the interfacial phase is an important indicator for assessing the composite material,which plays a role in the transfer of mechanical and thermal properties between the matrix phase and the reinforcing phase.For glass fiberreinforced resin composites,polyurethane resins are commonly used as the matrix phase,which has the characteristics of both soft and hard chain segments.With its block structure,polyurethane has good mechanical properties,chemical solvent resistance,high,and low temperature resistance,and is widely used in the preparation of resinbased composites.Previous studies have shown that the interfacial properties of glass fiber-reinforced resin composites have an important influence on their structural properties,mechanical properties,and thermal properties,therefore,it is greatly important to construct a stable interfacial phase in glass fiber-reinforced resin composites.Based on the previous research on the molding mechanism of polyurethane resin by the group,it is proved that the binary solvent N,N-dimethylformamide/toluene(DMF/TL)system can effectively regulate the molecular rearrangement of polyurethane,and can effectively improve its interfacial bonding ability when combined with inorganic particles for molding.In order to achieve the modulation of the interface between glass bulk fibers and polyurethanes,this paper used this system to prepare the glass bulk fiber/polyurethane composite fibers,and mainly investigated the microstructure,mechanical properties,and interfacial properties between unmodified glass fibers,silane coupling agent-modified glass fibers,carbon nanotubegrafted glass fibers,and polyurethanes,and the three main conclusions are as follows.(1)Unmodified glass fiber/polyurethane composite fibers(GFPU)were prepared.At different filling amounts of glass fibers,hydrogen bonding between the glass fibers and the polyurethane resin was generated and affected the microphase separation structure of the polyurethane.The thermal stability of the GFPU composite fibers was enhanced by the combined effect of hydrogen bonding and glass fibers,and its onset decomposition temperature was increased by 8.99% compared to that of the polyurethane resin,but the formation of the microcrystalline structure of composite fibers was hindered.Among them,the maximum breaking strength of 4% GFPU was2.69 ± 0.19 c N/tex,tensile strain was 1877.53 ± 0.15 %,and Young's modulus was 0.98± 0.37 c N/tex,which exhibited the best force-integrated chemical properties.(2)Coupling agent-modified glass fiber/polyurethane composite fibers(MPTSGFPU)were prepared.Stronger hydrogen bonding was generated between the modified glass fibers and the polyurethane resin.The onset decomposition temperatures of0.5MPTS-GFPU and 4MPTS-GFPU fibers were increased by 0.74% and 1.20%,respectively,compared to 4%GFPU under hydrogen bonding.The modification with coupling agent improved the interfacial bonding ability of the composite fibers,and the0.5MPTS-GFPU had the best overall mechanical properties with maximum breaking strength,tensile strain,and Young's modulus of 3.42 ± 0.13 c N/tex,1198.24 ± 0.12 %and 0.96 ± 0.11 c N/tex,respectively.The 0.5MPTS-GFPU composite fibers had the best interfacial bonding strength,and the maximum pull-out force of its microsphere debonding was 5.43 N.(3)Carbon nanotube graft-modified glass fiber/polyurethane composite fibers(CNT@GFPU)were prepared.Stronger hydrogen bonding was generated between the grafted glass fibers and polyurethane resin.In the presence of hydrogen bonding,the onset decomposition temperatures of 8%CNT@GFPU and 15%CNT@GFPU were increased by 0.65% and 0.92% compared to 0.5MPTS-GFPU,respectively.The modification with coupling agent improved the interfacial bonding ability of the composite fibers,and the 8%CNT@GFPU had the best overall mechanical properties with maximum breaking strength,tensile strain,and Young's modulus of 3.41 ± 0.06 c N/tex,1411.78 ± 0.02 % and 1.46 ± 0.17 c N/tex,respectively.The 8%CNT@GFPU composite fibers had the best interfacial bonding strength with a maximum microsphere debonding pull-out force of 6.43 N.