(a) Sayyiduna Ibn Abbas (may Allah be pleased with them both) said that the Prophet (peace and blessings be upon him) "forbade pure silk"; if its warp is silk, then there is no harm in wearing it.
(b) In the hadith of Ibn Jurayj (may Allah have mercy on him) there is: a garment whose warp is silk and whose weft is not silk, and which is not pure silk, there is no harm in wearing it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخوف / 6087