| Apocynum venetum is an ideal raw material for natural textile fibers,which has the advantages of good moisture absorption,high softness,and slender fibers.With the gradual improvement of people's pursuit of ecological,healthy and environmentally friendly textiles,apocynum fiber has become more and more popular due to its excellent properties such as renewable,abundant reserves,antibacterial health and so on.However,the traditional chemical degumming technology has a long production process,a large amount of chemicals,a high waste water discharge,and the fibers are easily damaged and have low uniformity,which limit the further development and utilization of apocynum fiber.Therefore,it is urgent to develop a green and efficient The new degumming technology.In the process of studying the separation of plant fibers,analyzing the agglomeration law of fibers in their natural state,and mastering the law of changes in the length and fineness of fibers of different scales during the degumming process,can effectively guide the preparation of high-quality fibers.In addition,physical degumming methods such as microwave and ultrasonic have proven to have the advantages of high efficiency,energy saving,and green in recent years,which are expected to reduce the disadvantages of traditional chemical degumming techniques.Therefore,this subject designed a microwave pretreatment-assisted ultrasonic degumming technology,and systematically studied the effect of different treatment conditions on the degumming effect of apocynum fiber.The research content and results are as follows:1.The natural aggregation state of fibers in the plant bast was studied,apocynum bast was taken as the research object,and kenaf was introduced for comparative analysis.After slicing the hemp phloem,use the micro-infrared imaging technology(Micro-FTIR)to observe the chemical composition distribution in the phloem in situ.Combined with the SEM image,it can be found that the apocynum venetin fiber is more evenly distributed in the phloem and the colloid is looser.The single fibers of hemp aggregate and combine into tight bundles of fibers and are tightly combined with the glue,which explains the advantages of apocynum fiber used in textile processing from the natural structure.2.Prepare multi-scale fibers for apocynum and kenaf respectively,and analyze the fiber morphology.The average diameter of apocynum and kenaf fiber bundles that are mechanically or manually peeled off from the bast is within 100?120 ?m;after degumming,apocynum bundle fibers with an average diameter of less than 20 ?m or red fibers with an average diameter of about 50 ?m can be obtained.Hemp bundle fiber: Apocynum or kenaf single fiber with an average diameter of about 10 ?m can be obtained under acid oxidation conditions.The study found that the length and diameter of the two kinds of hemp fibers were normally distributed as a whole,but the distribution of apocynum fiber was more concentrated,and the length and diameter of the apocynum fiber were closely related.3.The effects of different microwave pretreatment conditions on the microstructure,chemical composition,fiber diameter and other properties of apocynum fiber were studied.Within a certain range,the greater the intensity of microwave pretreatment,the higher the cellulose content in apocynum fiber,the lower the gum content such as lignin and hemicellulose,and the smoother fiber surface.At the same time,during this process,the average fiber diameter gradually decreases and the main fiber diameter accounts for a larger proportion,which represents an increase in fiber uniformity.On this basis,the optimal microwave pretreatment process parameters were determined: the concentration of NaOH in the degumming solution was 1%,the treatment temperature was 120?,and the treatment time was 15 min.4.This project developed a microwave pretreatment assisted ultrasonic degumming technology,compared with the traditional chemical two cooking method has obvious advantages.The amount of chemicals used during the degumming process was reduced to 44.8 percent and only 31.2 percent of the treatment time was required.At the same time,the average fineness of apocynum fiber obtained by the new method is 3100 Nm,and the average length is 26.54 mm,the fracture strength is 7.67 c N/dex,and the whiteness is more than 80%,which is better than the traditional chemical method,and the fiber uniformity is higher,and the spinnability is better. |
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