聚乳酸非织造材料的后牵伸辅助熔喷成形工艺及其力学性能

Preparation and mechanical properties of polylactic acid nonwovens via post-drafting assisted melt blown process

为改善聚乳酸(PLA)熔喷非织造材料的力学性能,在PLA热力学性能实验分析的基础上,采用后牵伸辅助熔喷成形工艺一步法制备了高结晶度的PLA熔喷非织造材料,并对材料的外观形态、拉伸断裂性能和顶破性能进行分析。结果表明:PLA聚合物的玻璃化转变温度为60.69℃,熔点为162.6℃,可以很好地用于高牵伸倍率的后牵伸辅助熔喷成形;随着牵伸倍率从1.0增大到3.0,高取向纤维(取向角度≤20°)的数量占比从28%增大至100%,超细纤维(纤维直径≤3μm)的数量占比从23%增大到67%;同时,材料的结晶度从1.22%增大到37.43%,纵向拉伸断裂强度增大到4.33 N/mm^(2),顶破强力增大到36.8 N,力学性能有所提升。

In order to improve the mechanical properties of polylactic acid(PLA)melt blown nonwovens,samples of PLA melt blown nonwovens with high crystallinity were prepared by a large scale and one step post-drafting assisted melt blown process,based on the experimental analysis of the thermodynamic properties of PLA polymers.The morphology,tensile and bursting properties of the prepared samples were evaluated.The results show that the glass transition temperature and melting point of PLA were 60.69℃and 162.6℃,respectively,suitable for the preparation at a high drafting ratio during the post-drafting assisted melt blown process.It was noted that with the drafting ratio increasing from 1.0 to 3.0,the proportion of high-oriented fibers(fiber orientation angle≤20°)was increased from 28%to 100%,and the proportion of the microfibers(fiber diameter≤3μm)was increased from 23%to 67%.The drafting ratio increase also caused the crystallinity to increase from 1.22%to 37.43%,the tensile breaking strength in machine direction to reach 4.33 N/mm^(2),and the bursting force to 36.8 N,demonstrating improvement of the mechanical properties of the PLA melt blown nonwovens due to the post-drafting assisted melt blown process.