Preparation Of Pu Electrospun Submicron Fiber Core-spun Yarn And Its Antibacterial Function

The novel coronavirus(COVID-19)that broke out at the end of 2019 and quickly ravaged the world has made people realize the importance of scientific protection,disease prevention and the use of antibacterial products.The loose and porous structure of textiles is not only conducive to bacterial attachment,but also the sweat and oil produced by human metabolism are more likely to become a breeding ground for bacteria.Compared with the antibacterial finishing technology of fabrics with high pollution and poor durability,the electrospinning core-spun yarn technology can wrap the sub-micron fibers with antibacterial function on the surface of the yarn and perform subsequent processing in the traditional spinning process.Compared with pure electrospinning yarn,electrospun core-spun yarn not only has the mechanical properties of core yarn,which meets the requirements of on-machine manufacturing,but also has the surface interface effect and rich physical and chemical properties brought by the ultra-low scale of sub-micron fibers.Without changing the traditional spinning process,the added value of yarn has been greatly improved.The article selects polyurethane(PU),a polymer with high elasticity,wear resistance and good biocompatibility,which is equipped with a more efficient and broad-spectrum quaternary phosphonium salt antibacterial agent than quaternary ammonium salts,and uses electrospinning core-spun yarn technology to prepare antibacterial-Polyurethane submicron fiber core-spun yarn,and study its various properties.Firstly,three different types of polyurethane were selected,and the effects of polymer molecular weight,solution concentration,spinning parameters and spinning environment on the fiber morphology were explored through single factor experiments.The lower molecular weight PU-2(Mw=21348)was electrospray thin film at each concentration,while the fiber morphology could be observed in the higher molecular weight PU-1(Mw=99993)and PU-3(Mw=120231).Controlled variable experiments were carried out for the problems of beading and fiber sticking,and the results showed that when the solution concentration was low(26wt%),increasing the humidity(RH=60%)could reduce beading;while the higher concentration(29wt%)needed to reduce the humidity(RH=20%)to obtain fibers with uniform morphology.In order to explore a solution formulation with wider environmental adaptability,THF with a lower boiling point was selected to form a blend solvent system with DMF.With the increase of THF content,the beading and adhesion between fibers disappeared.When the THF content was 50%,The spinning solution can obtain fibers with good morphology under different humidity(RH=20%,40%,60%)environments.Secondly,electrospun submicron fiber core-spun yarns were prepared using the optimal dope formulation obtained in the previous chapter.Cotton,polyester DTY and spandex were selected as core yarns.As the yarn diameter increased(polyester DTY < cotton < spandex),the coverage rate of the yarn decreased from 134.54% to 8.59%.After coating the PU sub-micron fibers,the strength improvement rates were 5.1%,14.9% and 4.6%,respectively.The submicron fiber thicknesses of the outer layers of the three core-spun yarns were calculated from the scale bar of the cross-sectional SEM,which were 20 ?m,30 ?m and 16.7 ?m,respectively.Using the STOLL computerized flat knitting machine to weave the above-mentioned core-spun yarns,the results show that the physical properties of the core yarns are an important factor in determining the knitability of the fabric,and the yarns with good strength and resilience can be obtained within a certain range of machine parameters.Good looking fabric.Using spandex as the core yarn,the fiber peeling during the weaving process of the PU and PAN core-spun yarns was compared.PAN sub-micron fiber corespun yarn has obvious sub-micron fiber peeling at the yarn guide,yarn guide,etc.,and the defects formed by the accumulation of deposited PAN fibers are observed under the microscope,while PU core-spun yarn does not have the above situation.A knitted structure with uniform color and regular organization can be observed.Using spandex as the core yarn,adding tetradecyl trimethyl ammonium chloride(TTAC)and tetradecyl n-tributyl phosphorus chloride(TTPC)respectively,to prepare antibacterial PU submicron fiber core yarn,adding TTAC/TTPC After that,the conductivity of the spinning solution increased by more than 500 times,and obvious electric field interference appeared in the conjugate spinning device.It was observed under the electron microscope that with the increase of the concentration of TTAC,the number of coated submicron fibers decreased.The fibers are uniformly packed and dense,showing a good skin-core structure.In addition,after adding TTAC and TTPC,the diameter of PU submicron fibers decreased from 2-3 ?m to about 600 nm.Finally,infrared detection and energy spectrum analysis were carried out on the prepared TTAC and TTPC core-spun yarns,and the characteristic absorption peak C-N bond of quaternary ammonium salts was found in TTAC/PU core-spun yarns;in TTPC-PU core-spun yarns The characteristic absorption peak C-P bond of phosphorus-containing polymer was found,and the unique P element of TTPC was detected by EDS,which proved that TTAC and TTPC were combined into submicron fibers.Quantitative antibacterial detection of fabrics was carried out.With the increase of concentration,the bacteriostatic rate of TTAC against Staphylococcus aureus increased from 89.29% to 94.64%,and the bacteriostatic rate against Escherichia coli increased from 83.79% to 86.54%;Excellent bacteriostatic effect,with more than 99% bacteriostatic rate against Escherichia coli and Staphylococcus aureus.After 50 times of washing,the bacteriostatic rate of TTAC against Staphylococcus aureus dropped to 74.19%;the bacteriostatic rate against Escherichia coli dropped to 61.42%;The bacteriostatic rate of Staphylococcus aureus remains above99.9%,which has great potential application value.