All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
It is permissible to use hair ties. Nevertheless, ties that contain hair, even if it is artificial, should be avoided, even if the user is a married woman and her husband allows her to do so. This is to comply with the opinion that absolutely disallows the attachment of any kind of hair extensions.
It is permissible to use hair ties that do not contain hair of any kind. In Al-Majmoo‘, An-Nawawi said:
He (Al-Qadhi ‘Iyadh) said that attaching extensions of wool and pieces of clothes to the hair is the same as attaching hair extensions, according to the majority of scholars. Al-Layth ibn Sa‘d, however, permitted attaching anything other than hair. The first opinion is the sound one, based on the hadith on the authority of Jabir in which the Prophet, sallallaahu ‘alayhi wa sallam, forbade a woman attaching anything to her hair. [Muslim] This is inclusive of everything. Tying hair with colored silk ties and other things which are not similar to hair is not forbidden. Al-Qadhi reported a consensus of the scholars concerning this.
Allaah Knows best.