Formation of Continuous Pore Structures in Si–C–O Fibers by Adjusting the Melt Spinning Condition of a Polycarbosilane–Polysiloxane Polymer Blend

Abstract

A polymer blend containing polycarbosilane (PCS) and 15 mass% of polyhydromethylsiloxane (H-oil) was prepared and the properties of the polymer melt were investigated in order to clarify the mechanisms of continuous pore formation. Melt viscosity decreased as the H-oil content increased. Moreover, the saturation of the plasticizer effect of H-oil on the viscosity and apparent turbidity of the melting polymer suggested that the compatibility of H-oil to PCS in melting was limited at 15 mass%. Gas chromatography data after heating showed that an amount of evolved hydrogen at 573 K was increased by 15 mass% of H-oil addition. The fibers formed by the melt-spun of the polymer blend at 578 K mainly possessed a single pore at the center of the fibers' cross section. On the other hand, the fibers melt-spun at 543 K usually included multiple pores, and the fibers melt-spun at 538 K included a number of tiny pores. It is proposed that the evolved hydrogen can be dissolved in the polymer melt, and the desaturation process of the dissolved gas during the fiber spinning with a sudden temperature reduction likely determined the size and location of pores in the fibers.

Preceramic polymer‐derived SiOC fibers by electrospinning

“…Furthermore, their cross‐sections do not contain any macroscopic defect [see Figure (b,d)]. The SiOC fibers produced in this work exhibit both a smaller average diameter and a more controlled morphology than those previously reported by previous literature …”

“…SiOC fibers have been mainly prepared by mechanical spinning from a viscous melt or a sol–gel solution. Kita reported the preparation of SiOC fibers by melt spinning from a polymer blend of polycarbosilane (PCS) and 15 wt % of polyhydromethylsiloxane (H‐oil), producing fibers with a diameter, after pyrolysis, of about 30 μm. In Ruan's work the polysiloxane fibers were drawn from a sol–gel system of tetraethoxide (TEOS) and vinyltrimethoxysilane using a glass bar, and then pyrolyzed into SiOC fibers with a diameter of about 26 μm.…”

Silicone Resin Applications for Ceramic Precursors and Composites

“…Blends of silicones with ordinary ceramic precursors, like polycarbosilanes, polysilazanes and polysilanes, are another interesting theme. For example, polycarbosilane (PCS), which is famous as a precursor of continuous silicon carbide base fibers, accepts the dissolution of various silicone oils [ 44 , 45 ]. Since main chain structure of silicones (Si-O-Si) is different from the chain structure of PCS (Si-CH 2 -Si), compatibility of the silicone oils to PCS is intrinsically limited.…”

Facile one-pot formation of ceramic fibres from preceramic polymers by pressurised gyration

“…Generally, SiOC fibres are prepared by mechanical spinning of a melt or sol-gel solution [9][10][11]. Electrospinning was also recently explored to fabricate continuous SiOC fibres with different chemical compositions [1][2][3][4].…”