Preparation of high melt flowing index polyethylene masterbatch and spinnability of infrared melt-blown nonwovens
Objective The application of micro/nano ultrafine fiber aggregate materials with high transmittance and medium infrared performance in intelligent buildings,physical therapy and health energy is constantly expanding.Polyethylene(PE),as a typical high transmittance medium infrared material,has not yet received systematic research and applications in relation to its infrared transmittance ultrafine fiber materials.Melt-blown method can be used to prepare PE ultrafine fiber aggregates with high quality and efficiency.However,not much research has been witnessed on PE raw materials for melt-blown performance and melt-blown formation,and there is no PE melt-blown material with satisfactory performance in the market.This study prepared PE master batches with high melt index(HMI-PE)for melt spraying,further prepared PE melt spraying materials(PE-MBs),and studied their infrared transmittance.Method Using spinning grade PE as raw material,high melt index PE master batches(HMI-PE)were prepared by reactive extrusion using a synergistic method of plasticizer(plasticizer,polyethylene wax(PEW))and catalyst(initiator,DCP)chain breaking.The rheological properties,molecular weight and distribution,crystallization performance,and thermal stability of the HMI-PE master batches were investigated.Furthermore,PE melt-blown materials(PE-MBs)were prepared using SJ-25 micro melt blown testing mechanism,and the apparent morphology and mechanical of PE-MBs were studied.The infrared transmittance performance was characterized and analyzed.Results Under the same temperature conditions,as the mass fraction of PEW increased,the melt index(MI)of HMI-PE master batches continuously increased.At different temperatures,the magnitude of the increase in MI of HMI-PE master batches increased with the increase of temperature.Under constant temperature conditions,the complex viscosity showed a decreasing trend with an increase in shear rate,resulting in a decrease in molecular weight and a wider distribution of molecular weight.The glass melting temperature and cold crystallization peak of HMI-PE master batches generally shifted to the left,and with the increase of PEW content,a melting peak with lower temperature and wider peak range would appear,without significant impact on thermal stability.When the mass fraction of PEW was greater than 30%,the HMI-PE masterbatches reached over 200 g/(10 min)(230℃),exhibiting great melt-blown spinnability.The fiber diameter of PE-MBs were distributed in an approximate normal pattern,and with the increase of melt index,the fiber diameter decreased to 7.72 μm.The longitudinal tensile strength of PE-MBs decreased with the increased of PEW content,while their flexibility and overall mechanical properties became better.Research had shown that the infrared transmittance was related to the thickness of the material and the thickness of the fibers.The thinner the material,the finer the fibers,and the higher the infrared transmittance.Conclusion The synergistic method of plasticizer and catalytic chain breaking can be used to prepare high melt index polyethylene master batches,showing good melt-blown spinnability.PE melt-blown nonwoven materials have narrow absorption peaks in the mid infrared band,and their infrared transmittance can reach over 92%,making them an excellent infrared transparent material.
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维普
