热定形超喂率对大直径涤纶单丝结构与性能的影响

探究了在热定形过程中超喂率对大直径涤纶单丝结构与力学性能的影响。对制备的单丝进行了拉伸和热收缩性能测试,并通过广角X射线衍射、小角X射线散射及声速取向等方法对微观结构进行了表征。结果表明,随着超喂率的降低,单丝在热定形中受到的张力增大,有利于链段沿着拉伸方向排入晶格,结晶度小幅上升,而在纤维径向上的晶粒尺寸及片晶直径减小。超喂率对单丝非晶区结构影响显著,低超喂率下获得的单丝内部形成的非晶区分子链的取向程度大且含量低,导致纤维断裂强度及初始模量较大且断裂伸长低。此外,低超喂率条件下单丝纤维非晶区取向高,致使热收缩率较大。

Effect of Overfeeding Rate in Heat-Setting Process on the Microstructure and Mechanical Properties of Coarse Polyester Monofilament

The effect of overfeeding rates on the microstructure and mechanical properties of large diameter polyester monofilaments during heat-setting process was investigated. The tensile and thermal shrinkage properties of prepared polyester monofilaments were evaluated, and underlying microstructures were also characterized by using wide-angle X-ray diffraction, small-angle X-ray scattering, and sonic orientation.The tensions within the samples increased with the decrease of the overfeeding rate during the heat-setting process, which was beneficial for the molecular chain to be discharged into the lattice along the stretching direction, resulting in the increase of the crystallinity slightly as well as the decrease of crystal size in the fiber axis and lamellar diameter. The overfeeding rate has a significant effect on the amorphous structure of the monofilament. The monofilament with high-oriented and low-fraction amorphous were formed at a low overfeeding rate, leading to the high breaking strength and initial modulus as well as low elongation at break. In addition, the monofilament with high amorphous orientation under low overfeeding rate has a high thermal shrinkage.