Largely improved dimensional stability of short carbon fiber reinforced polyethersulfone composites by graphene oxide coating at a low content

For aviation and automobile applications, etc., high dimensional stability is critically important since the mismatch in linear coefficient of thermal expansion (LCTE) between polyethersulfone (PES) and metal materials would lead to dimensional instability. In this work, the GO-coating treatment is proposed to greatly enhance the dimensional stability of injection molded short carbon fiber (SCF)/PES composites. It is shown that the LCTE of the GO-coated SCF/PES composites is significantly reduced along both the longitudinal and transverse directions. At the low content of 0.5 wt% GO, the LCTE of the GO-coated SCF/PES composite is largely reduced by 67.0% along the longitudinal direction and 28.9% along the transverse direction in the temperature range from −196 °C to 150 °C. The enhanced dimensional stability by the addition of GO-coated SCFs is much higher than that by the addition of un-treated SCFs or the separate addition of GO and SCFs. The dynamic mechanical analysis (DMA) shows that the composite storage modulus and loss modulus are effectively enhanced by the GO-coating, indicating that the GO coating treatment brings about a strong interfacial interaction between SCFs and PES. It is regarded that the chain movement of PES would be restricted by the enhanced SCF/PES interfacial interaction and the restricted movement of PES chains by the strong SCF/PES interfacial adhesion finally leads to a significantly lowered composite LCTE.

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