Mechanical properties of C/C composites processed by wet impregnation and P-CVI methods

Abstract

Wet impregnation with phenolic resin and P-CVI methods were used to manufacture C/C composites. The influence of impregnation process of porous 2D carbon fibre substrate with resin and pyrocarbon deposited by CVD technique on mechanical properties of formed composites was studied. The results indicate that using P-CVI method large pores remain in the matrix resulting in lower mechanical strength. This fraction does not undergo any changes during thermal treatment. The flexural modulus of C/C composites depends mainly on the type of reinforcing fibres. The values of moduli measured in composites obtained by both methods do not differ significantly.Comparison of two methods of fabrication of C/C composite show that much better strengths can be achieved by forming the carbon matrix in solid state.

Performance of novolac resin‐ and resole resin‐based carbon/carbon composites in relation to their fabrication conditions

“…1,11,12 Factors that may cause composite failure are (i) deterioration of the mechanical properties of the fibres due to chemical attack by polymeric matrix pyrolysis gases at high temperatures, (ii) residual stresses developed due to the different thermal expansion coefficients of matrix and fibres, (iii) fibre/matrix debonding, (iv) manufacturing flaws and (v) development of large pores. 1,2,13 Phenolic resins are produced via polycondensation step-growth polymerisation between phenol and formaldehyde, in which two different condensation reactions can occur, creating: (i) an ether bridge between the phenol-free position and the methylolphenols and (ii) a methylene bridge between the methylolphenols themselves. 3,14,15 The structure and the properties of the produced phenolic resins depend strongly on the molar ratios of the reactants, and the type and concentration of the catalyst.…”

“…Apart from the density/porosity of the matrix and the pyrolysis heating rate, the performance of C/C composites is also related to the volume fraction and direction of the fibres relative to the direction of the applied stress, 2,9,10 fibre architecture 1,2 and type and degree of fibre‐surface treatment 1,11,12 . Factors that may cause composite failure are (i) deterioration of the mechanical properties of the fibres due to chemical attack by polymeric matrix pyrolysis gases at high temperatures, (ii) residual stresses developed due to the different thermal expansion coefficients of matrix and fibres, (iii) fibre/matrix debonding, (iv) manufacturing flaws and (v) development of large pores 1,2,13 …”

Effect of Varying Initial Processing Temperature on Mechanical Properties of Carbon Epoxy Composites

“…Zhang et al [7] focused on wool fiber composites processed by compression molding and optimum processing parameters were identified for the combination. Choupin tested wet impregnation processing parameters for mechanical properties with phenolic resin for the mechanical properties [9] as was done in another research by Michlowski [8]. PEEK thermoplastic composites and their processing parameters were linked in another study and Schell et al [14] described the significance of equipment, production rate and energy cost for processing at lowest possible pressure and temperature with shortest cycle time.…”

n-Heptane Hydroisomerization over a SO42–/ZrO2@SAPO-11 Composite-Based Catalyst Derived from the Growth of UiO-66 on SAPO-11

“…The conventional methods for preparing composite materials include wetness impregnation (WI) and chemical vapor deposition (CVD). − The WI method is attractive due to its low cost and technical simplicity. However, the composite prepared by the WI method has a poor dispersion and large particles for the supported components .…”