Carbon fiber surfaces and composite interphases

Effect of carbon fiber surface functional groups on the mechanical properties of carbon-carbon composites with HTT

After curing, phenol-formaldehyde resins were postcured at 230°C in air for 32 h and then carbonized and graphitized from 300 to 2400°C. Thermal fragmentation and condensation of the polymer structure occurred above 300°C. The crystal size of the cured phenolic resins decreased with the temperature increase. Above 600°C the original resin structures disappeared completely. Below 1000°C the stack size (Lc) and crystal size (La) were small. Above 1000°C the Lc increased with the increasing treatment temperature. The carbonized and graphitized resins were characterized using Raman spectroscopy. Below 400°C there were no carbon structures in the Raman spectra analysis. Above 500°C the G and D bands appeared. The frequency of the G band of all carbonized and graphitized samples shifted to 1600 cm−1 from the 1582 cm−1 of graphite. The D band shifted to 1330 cm−1 from the 1357 cm−1 of the imperfect carbon. The carbonized and graphitized phenolic resins could not be considered as truly glassy or amorphous carbon materials because they had some degree of order in the basal plane. However, the crystal size was very small even at 2400°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1084–1089, 2001

Microstructural changes of phenolic resin during pyrolysis

The properties of the fiber/matrix interface in carbon fiber-reinforced composites play a dominant role in governing the overall performance of the composite materials. Understanding the surface ch...

Plasma surface modification of carbon fibers: a review

The preparation of silicon oxycarbide glasses and structure changes of polysiloxane precursors during heat-treatment in oxidative and nitrogen atmosphere are studied by 13 C and 29 Si magic angle spinning (MAS) NMR, Fourier-transform infrared (FTIR) spectroscopy and thermogravimetry analysis (TG). The reaction mechanisms in inert and oxidation conditions are discussed with respect to the chemical composition of the used precursors. We focused on the formation of new silicon oxycarbide units as well as a highly condensed aromatic carbon phase, the structure of which is discussed. A correlation of thermo-oxidative properties with chemical structure of prepared materials as well as with conditions of their preparation is given.

Structure of silicon oxycarbide glasses derived from poly(methylsiloxane) and poly[methyl(phenyl)siloxane] precursors

Oxygen plasma treatment was used to introduce functional groups on the surface of polyacrylonitrile-based carbon fibers. The fiber surface was examined by X-ray photoelectron spectroscopy after treatment. The amount of functional groups on the fiber surface initially increased with increasing treatment time up to 2 min, thereafter remaining constant. The variation of surface energy with plasma treatment showed a similar trend. The plasma treatment affected the surface area and the mechanical properties of carbon fibers. The surface area increased but the mechanical properties decreased with increasing treatment times. The plasma treatment also changed the morphology of the fiber surface.

Properties of carbon fibers modified by oxygen plasma

Effect of processing parameters on the mechanical properties of carbonized phenolic resin

The effect of cure on the crystallization rates of polyphenylene sulfide (PPS) and PPS/carbon fiber composites has been studied by differential scanning calorimetry (DSC). The crystallization rate of PPS increased with increasing degree of cure. The carbon fiber acted as a nucleating agent to enhance the crystallization rate of PPS. The fully cured PPS seemed to be saturated with nucleating sites formed through the cure reaction. Therefore, the presence of carbon fibers gave little effect on the crystallization rate of the fully cured PPS.

Crystallization behavior of polyphenylene sulfide (PPS) and PPS/carbon fiber composites: Effect of cure

Differential scanning calorimetry (DSC) was used to investigate the solid-state cure process of poly(phenylene sulfide)(PPS) resin. Virgin PPS resin in an open sample pan was cured in DSC cell. Either air or oxygen was used as a curing atmosphere. Cure temperatures were in the range of 200 and 250 °C, which are below the melting point of PPS resin. Cure temperature as well as atmospheric condition influenced the cure behavior of PPS in the solid state. Both the rate and the amount of cure increased with increasing cure temperature. On the other hand, the time to reach the maximum cure rate was independent of cure temperature. Changing the atmosphere from air to oxygen increased both the cure rate and the amount of cure. The size effect of PPS particles on the cure reaction was also discussed.

Kwang Hee Lee

Papers

Properties of carbon fibers modified by oxygen plasma

Effect of processing parameters on the mechanical properties of carbonized phenolic resin

Crystallization behavior of polyphenylene sulfide (PPS) and PPS/carbon fiber composites: Effect of cure

A thermoanalytical study on solid‐state cure of poly(p‐phenylene sulfide)

Resin impregnation efficiency of carbon-carbon composites