| In the post-epidemic era,the production capacity of the PP melt-blown industry was becoming saturated,and the exploration of new materials and new structures was imminent.Taking the micro-compatible blend system as the research object,the preparation of multi-scale nano-micro-structured non-woven materials based on the "tug-of-war effect" during the formation of meltblown fibers was one of major development direction.Polybutylene terephthalate(PBT)was a new melt-blown material that had a wide range of applications in the fields of blood filtration and oilwater separation.PBT and PP slices were used as raw materials,the component content and process parameters were adjusted to control the nano-microstructure,the regulation mechanism of the "partially compatible" component forming the multi-scale nanomicrofiber structure were studied,the theoretical basis and experimental verification for the development of new blended meltblown nonwovens of PBT were provided...The thermal properties and rheological properties of melt-blown chips indirectly reflect the compatibility and spinnability of the two-phase melt blending.The experimental results showed that the PP/PBT mixed melt(50/50)was in the temperature range of 275 ℃-290 ℃ in a "partially compatible" state.The apparent viscosity of PP/PBT mixed chips with different PP content(0 wt%,3 wt%,5 wt%,7 wt%,10 wt%,13 wt%)under the condition of 275 ℃-280 ℃ was similar and the fluidity was excellent,indicating the addition of PP wound not interfere with the formation of PBT meltblown nonwoven materials.The main research contents were as follows:This paper firstly passed a series of melt-blown pre-experiments,and determined the production process of PP/PBT blended melt-blown nonwoven materials as follows:spinning temperature was 277 ℃,single-hole extrusion rate of metering pump was 0.2g/min,drafting air temperature was 273 ℃,drafting air pressure was 0.018 MPa and receiving distance was 13 cm.PP/PBT blended raw materials were used to prepare melt-blown nonwoven materials,and their structure and properties were characterized.The experimental results showed that the blending of PP chips reduces the average fiber diameter(2.0-3.7 μm)of the blended melt-blown nonwoven material,which was smaller than the pure PBT melt-blown web(3.968 μm),and the fiber diameter distribution CV value(41-81%),which was higher than pure PBT melt-blown fiber web(29.36%).When mixed with 5 wt% PP,the PP/PBT blended melt-blown nonwoven material had the most obvious dual-scale distribution of nanofiber diameters.The minimum fiber diameter can reach 200 nm,the maximum fiber diameter was 9 μm,and the fiber diameter distribution CV value was 80.83%.Based on PP/PBT blended raw materials mixed with 5 wt% PP,the scale of the blended melt-blown fiber was adjusted as follows: the process parameters,and the optimal process plan for the nano-microstructure was explored.The experimental results showed that the formation of nano-microfiber structure was restricted by the phase state of the melt interface of the mixed melt.When the melt temperature higher than 290 ℃,the blended melt become homogeneous and gradually loses the conditions for forming the nano-microstructure;Low drafting wind pressure and the receiving distance lead to the effect on nano-micro forming was no longer obvious;while high drafting wind pressure was more conducive to the formation of nano-microstructures.Experiments showed that when the drafting air temperature was 270 ℃,the drafting air pressure was 0.02 MPa,and the receiving distance was 20 cm,the most obvious dualscale melt-blown fiber web was obtained.The minimum fiber diameter was about 300 nm,and the maximum fiber diameter was 10 μm.The diameter distribution CV value reached 98.53%. |
