Evidence for chemical bond formation between surface treated carbon fibres and high temperature thermoplastics

Abstract

The interaction between surface‐treated carbon fibres and high temperature thermoplastics (polyethersulfone and polycarbonate) was studied by measuring the interlaminar shear strength of unidirectionally reinforced composites with a fibre volume content of 60%. The ILSS‐values were correlated with the surface concentration of the acidic functional groups of the carbon fibres, as analysed by temperature programmed desorption and contact angle measurements using basic aqueous solutions (pH ≥ 12). Linear relationships were found with both the amount of carbon dioxide desorbed by decomposition of carboxylic surface groups and the work of adhesion calculated from the measured contact angles. This result could be interpreted as a consequence of acid–base interactions with the basic polymers. However, strongly acidic carboxylic groups are decomposed during processing of the composites. Therefore, the high ILSS‐values can only be explained by chemical bonds being formed with the functional groups of the polymers during decomposition of the carboxylic surface groups. © 1994 John Wiley & Sons, Inc.

Recycled carbon fiber filled polyethylene composites

“…The peaks having mean positions at about 3450, 2913, and 1620 cm 21 are derived from hydroxyl (À ÀOH), carboxylic acid (À ÀCOOH) and carbonyl (À ÀC¼ ¼O) functionality and are formed due to the degradation of the epoxy resin during the CARBONCLEAN 1 process, a combined thermal and chemical treatment of the epoxy/CF composite. The presence of these groups on the surface of the recycled CF provides a mechanism for good wetting between polymer and CF, [16][17][18] and as such account for, in part, the increase in strength and stiffness of the composites with increasing CF loading. Residual undegraded epoxy resin was also evident along the length and the tip of the fibers, see Figure 1(c,d), this residue may also aid dispersion of the CF in PE during melt mixing.…”

Influence of plasma pre-treatment of polytetrafluoroethylene (PTFE) micropowders on the mechanical and tribological performance of Polyethersulfone (PESU)–PTFE composites

“…Thus, the composites containing the standard PTFE exhibit higher specific wear rates than the plasma treated PTFE samples. The improvement of wear resistance of composites containing the plasma modified PTFE can be ascribed to the electro-negativity of the oxygen and the nitrogen atoms in the altered PTFE, which can form hydrogen bonds to the PESU[40] and the steel[39].…”

Physico-Chemical Characterization of Novel Epoxy Matrix System Reinforced with Recycled Short Milled Carbon Fibre

“…The FTIR spectrum of the SMCF shown in Figure 5 reveals the presence of the polar groups hydroxyl (-OH), carboxyl (-COOH) and carbonyl (-C=O) as suggested by respective peaks [17] observed at 3435, 2916 and 1613 cm −1 . Researchers [29]- [31] believe that these groups are formed during the SMCF recycling process. On the other hand, the existence of the corresponding peaks of these groups in the XPS spectrum of virgin carbon fibers [22] may tell a different story.…”