The preparation and characterization of plasticized PVA fibres by a novel Glycerol/Pseudo Ionic Liquids system with melt spinning method. (15th June 2020) - Xu, Yongjing
Graphical abstract: The novel "green solvent" pseudo ionic liquids (PILs) were synthesized and applied in the plasticization of PVA polymers to broaden the window of thermal processing of PVA. PILs were consist of 3 parts, including the choline chloride-based, cations and strong hydrogen bond acceptors, and all of the parts could form new hydrogen bonding with PVA chains to destroy the intra-/intermolecular hydrogen bonding of PVA, having smaller space volume and more efficiency in disrupting hydrogen-bonded interaction than other plasticizers, achieving the melt spinning of PVA. Highlights: The novel "green solvent" pseudo ionic liquids (PILs) and glycerol (GL)/PILs system were applied to plasticize PVA polymers, which not only improved the poor thermal processability, but also achieved the melt spinning of PVA for the first time. The GL/ChCI-GL system plasticized PVA fibres were successfully prepared with the melt spinning method. Abstract: To solve the problem of thermal processing of PVA polymers, the novel "green solvent" pseudo ionic liquids (PILs) and glycerol (GL)/PILs system were applied to plasticize PVA polymers, which not only improved the poor thermal processability, but also achieved the melt spinning of PVA for the first time. In this paper, different PILs (choline chloride-based, ChCI-based) were prepared and characterized. The plasticizing mechanism and the effects of GL/PILs system on PVA polymers were further investigated. Cation (OH), anion (Cl − ) and hydrogen bond acceptors in the GL/PILs plasticizing system could form strong hydrogen bonds with the hydroxyl groups of PVA. Compared with pure PVA, the plasticized PVA polymer provided a lower melting temperature, wider thermal processing window and better melt fluidity. Finally, the GL/ChCI-GL system plasticized PVA fibres were successfully prepared with the melt spinning method. The structure and properties were systemically investigated by scanning electron microscopy, fourier transform infrared, differential scanning calorimetry, thermal analysis, two-dimensional wide angle X-ray diffraction and yarn strength tester. The PVA fibre diameter was measured to be ~116 μm with a smooth surface, and the cross section was circular and uniform. The tensile strength and Young's modulus of PVA fibre were up to 1208 MPa and 23 GPa, respectively. The melt-spun PVA fibres with large fibre diameter and outstanding mechanical properties will provide an opportunity for cement-based reinforcement material.