Synthesis and spinnability of vinyl-grafted carbon nanotubes /polycarbosilane precursor with high ceramic yield

Abstract

Silicon carbide (SiC) fiber is a high-performance ceramic fiber mainly prepared by the polymer-derived ceramics (PDC) method. However, balancing the precursor's ceramic yield and spinnability is challenging in the preparation process. Herein, we proposed a new strategy, chemical bonding with PCS to form a high cross-linked network structure, utilizing the flexibility and high aspect ratio within MWCNTs. As a result, based on the spinnable PCS (57.58 %), only the incorporation of 0.05 wt% MWCNTs increase the ceramic yield by 21.66 %–70.05 % and 1 wt% MWCNTs achieved as high as 81.44 % when pyrolyzed at 900 °C. Moreover, the hybrid precursors showed good spinnability, except for the 1%-MWCNTs/PCS. In addition, the presence of chemical bonding and cross-linking structures has been thoroughly proven, and the mechanism behind the increase in ceramic yield has been further explored. MWCNTs occupied cross-linking sites and formed cross-linked structures to effectively reduce weight loss during thermal cross-linking in the 300–500 °C temperature range, thereby increasing ceramic yield. The increment of spinnable PCS in the ceramic yields can effectively reduce the preparation cost and enhance the performance of the SiC fibers using the PCS method.