并用非极性溶剂或弱极性溶剂进行重结晶。
The product was recrystallized by non-polar or low-polar solvent.
第三种方法包括：1将含极性取代基的染料分子合成；2控制染料分子的聚合或结晶过程。
The third approach involves: 1 the synthesis of certain molecules containing readily polarised groups of substituents, and 2 the controlled polymerisation or crystallisation of these molecules.
这是由于纤维在化学上不活泼，表面能低，表面缺乏极性基团，且是高度对称的亚甲基结构，使得纤维具有很高的结晶度和取向度。
Because the fiber is of chemical inertion, low surface energy, lack of polar groups, and highly symmetric methylene structure, the fiber has a high degree of crystallinity and orientation.
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