C_C-SiC_1.jpg
C/SiC composites

- One of my research interests is C/SiC composites. C/SiC composites can 
   maintain their outstanding strength at high temperature. Also, the fabric 
   structure makes these composites have higher fracture toughness than ceramic 
   monolith.
​
- C/SiC can be processed by liquid silicon infiltration (LSI) method. C/SiC can 
   be mass-produced with LSI, because this method utilizes the fast reaction 
   between carbon and liquid silicon. Furthermore, the LSI method is cheaper than 
   chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis (PIP) 
   method.
​
- The LSI method consists of three steps.
   ① Fabricating CFRP
   ② Pyrolyzing CFRP ​
   ③ Infiltrating liquid Si into the pyrolyzed CFRP
​
- There are several ways to enhance the mechanical properties of C/SiC 
   composites.
   ① Reducing the graphene-like crystallinity of pyrolyzed carbon preform
   ② Increasing the surface area of the pyrolyzed preform to react liquid Si
   ③ Modifying the interfacial bonding strength between the fibers and the matrix
   I have studied how cellulose nanofiber (CNF) can be used to enhance the 
   mechanical properties of C/SiC composites.
3D_woven.png
3D Woven Textile Composites

- 3D weaving technology gives us the possibility of the composite materials with 
   high damage tolerance and strong capability to fabricate complex-shaped parts.
   Since the layers inside the fabric structure are connected by the binding yarns, 
   the composites with 3D woven carbon preforms have intensive resistance to 
   delamination.  

- With 3D weaving, complex-shaped composite parts can be produced with 
   consistent properties regardless of the fabricator's skill level, because the 
   preform is formed in three dimensions. In contrast, it is difficult to fabricate 
   composite laminates with complex shape due to the laminates are 2D materials. 
​
- Recently, I have researched optimizing the fabrication process of C/SiC 
   composites with various 3D woven carbon preforms.
CNF.jpg
Cellulose Nanofiber-Based Composites

- Cellulose is abundant in nature (10^11-10^12 tons/year).  It has strong 
   mechanical properties and high crystallinity. Depending on the size, the 
   crystallinity, and the method of production, cellulose is classified into
   ① Micro fibrillated cellulose (MFC),  ② Cellulose nanofiber (CNF)
   ③ Microcrystalline cellulose (MCC),  ④ Cellulose nanocrystal (CNC)
   ⑤ Bacterial cellulose (BC),  ⑥ Electrospun cellulose nanofiber (ECNF)
​
- I have used CNF produced by the aqueous counter collision (ACC) method. The 
   advantage of ACC method is that it consumes less energy than other methods 
   and produce CNF with high crystallinity. 
​
- To disperse CNF into the phenolic resin, we can try various techniques such as 
   ball milling and three roll milling.
​
- I am interested in applying CNF to polymer composites, fiber-reinforced
   plastics, and pyrolysis behavior of CNF-added polymers.
EMI_2.png
Composites for Stealth and EMI Shielding Applications

- Since the carbon fiber is highly conductive materials, it reflects electromagnetic 
   wave (EM wave). With the high resistance to erosion and lightweight, CFRP is 
   promising candidate for EMI shielding materials. 

- FRP can be used to stealth application. By decreasing reflection  of EM wave 
   through absorption and the impedance mismatch, or by reflecting the wave in a 
   different direction, FRP-based radar absorbing structure (RAS) can reduce an 
   object's radar cross section (RCS).
​
- I have studied how CNF affect shielding effectiveness (SE) of C/Phenolic 
   composites by measuring electrical conductivity and calculating S-parameters 
   based on measured value.