可纺性竹原纤维的脱胶工艺及其性能

Degumming process and properties of spinnable natural bamboo fibers

针对传统竹原纤维制备过程能耗大、污染环境、时间长,且获得的纤维表面粗糙、长度低等问题,构建了氯化胆碱-乳酸低共熔溶剂(DES)脱胶、过氧乙酸(PAA)脱胶、DES协同PAA脱胶3种绿色脱胶方法。通过傅里叶变换红外光谱、扫描电子显微镜和X射线衍射仪等测试手段,对采用传统方法和3种不同绿色脱胶工艺所得纤维的理化性能进行了测试和表征。研究结果表明:制备竹原纤维的4种方法均可去除胶质部分,经DES溶剂脱胶可有效脱除竹原纤维的半纤维素,但木质素残余量高,PAA脱除木质素的效率最高,DES协同PAA脱胶制备的纤维素含量最高;随着竹原纤维无定形区域胶质部分的脱除,4种脱胶方式均可提高纤维的相对结晶度,但传统脱胶制备的纤维结晶度变化最小;DES协同PAA脱胶制备的纤维线密度最低(50.07 tex),断裂强度最高(2.98 cN/dtex),具有最佳的可纺性能。

Objective Bamboo is a promising alternative source of textile fibers by virtue of its rapid growth,ease of cultivation,wide availability and renewable nature.The preparation of traditional natural bamboo fibers has drawbacks such as high energy consumption,environmental pollution and long processing time,resulting in rough fibers with low length.Hence,it is of great practical value to explore for a cost-effective,eco-friendly,and efficient method for preparing natural bamboo fibers.Method Three green degumming methods were developed to address these issues,which are choline chloride-lactic acid deep eutectic solvent(DES)degumming,peracetic acid(PAA)degumming,and DES synergistic PAA degumming.Fourier-transform infrared spectroscopy(FT-IR),scanning electron microscopy,and X-ray diffraction were adopted to test and characterize the physicochemical properties of fibers obtained using conventional methods and the three different green degumming methods.Results FT-IR results show that the lignin benzene ring characteristic absorption peaks were near 1610 cm-1 and 1500 cm-1.The lignin benzene ring characteristic peaks were weakened by PAA and DES synergistic PAA treatment,indicating that PAA has good delignification effect.Besides,all four methods of preparing natural bamboo fibers can remove the gum part.DES consisting of choline chloride-lactic acid could effectively remove the hemicellulose of the bamboo chips,reducing from 12.85%to 8.67%.However,the residual lignin content remained high at 27.10%,close to 28.77%of bamboo chips.PAA had the highest efficiency in removing lignin,with only 2.05%remaining.The highest cellulose content was obtained by DES synergistic PAA degumming,at 86.72%.The surface of fibers prepared by DES synergistic PAA degumming was significantly less rough,its fibers surface was smoother.Furthermore,with the removal of the amorphous area of the glue part of natural bamboo fibers,it was shown that none of the four degumming methods changed the crystal structure of the fibers and all four deacetylation methods can increase the relative crystallinity of the fibers,among them,DES synergistic PAA degumming obtained the largest crystallinity of 69.22%.But the crystallinity of fibers prepared by conventional degumming changes the least,at 62.42%.Fibers prepared by DES,DES synergistic PAA degumming and conventional degumming all had high lengths of 6.97 cm,6.19 cm and 6.72 cm,respectively,with DES having the highest line density of 123.98 tex and DES synergistic PAA degumming having the lowest line density of 50.07 tex.Fibers prepared by conventional degumming had the highest moisture regain of 9.39%and DES had the lowest moisture regain of 6.55%.Fibers prepared by DES synergistic PAA degumming had the highest stress,strain and breaking strengths of 236.35 MPa,1.8%and 2.98 cN/dtex,respectively.Conclusion DES synergistic PAA degumming can more effectively extract natural bamboo fibers.Compared to conventional delignification processes,this method has advantages of lower chemical usage,reduced pollution and shorter processing time.It provides positive guidance for the preparation and development of spinnable natural bamboo fibers.