TY - JOUR A1 - Ho, K.K.C. A1 - Lamoriniere, S. A1 - Kalinka, Gerhard A1 - Schulz, Eckhard A1 - Bismarck, A. T1 - Interfacial behavior between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) N2 - Atmospheric-plasma fluorination was used to introduce fluorine functionalities onto the surface of carbon fibers without affecting their bulk properties. The interfacial adhesion between atmospheric-plasma-fluorinated carbon fibers and poly(vinylidene fluoride) (PVDF) was studied by means of direct wetting measurements and single fiber pullout tests. Measured contact angles of PVDF melt droplets on modified carbon fibers show that short exposure times of carbon fibers to atmospheric-plasma fluorination (corresponding to a degree of surface fluorination of F/C = 0.01 (1.1%)) leads to improved wettability of the fibers by PVDF melts. The apparent interfacial shear strength as a measure of practical adhesion, determined by the single-fiber pullout test, increases by 65% under optimal treatment conditions. The improved practical adhesion is not due to the formation of transcrystalline regions around the fibers or a change of the bulk matrix crystallinity or to an increased surface roughness; it seems to be due to the compatibilization of the interface caused of the atmospheric-plasma fluorination of the carbon fibers. KW - Carbon fibers KW - Fluorination KW - Contact angle KW - Interface KW - Adhesion KW - Surface area KW - Fiber properties PY - 2007 U6 - https://doi.org/10.1016/j.jcis.2007.04.076 SN - 0021-9797 SN - 1095-7103 VL - 313 IS - 2 SP - 476 EP - 484 PB - Elsevier CY - Orlando, Fla. AN - OPUS4-16026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ho, K.K.C. A1 - Kalinka, Gerhard A1 - Tran, M.Q. A1 - Polyakova, N.V. A1 - Bismarck, A. T1 - Fluorinated carbon fibres and their suitability as reinforcement for fluoropolymers N2 - The interaction between direct fluorinated carbon fibres and various fluoropolymers (ethylene-chlorotrifluoroethylene, poly vinylidene fluoride, fluorinated ethylene propylene copolymer and tetrafluoroethylene-perfluoro alkoxy vinyl ether copolymer) was studied by means of direct wetting measurements between fibres and the polymer melts and single fibre pull-out tests. The results of both techniques allow the adhesion behaviour between the fibres and the matrices to be predicted. The results obtained show that a low degree of surface fluorination of carbon fibres leads to an improved wettability between the fibres and fluoropolymer melts and this is an indicator for an improved thermodynamic work of adhesion. The apparent interfacial shear strength as measure of practical adhesion, determined by the single fibre pull-out test, increases with increasing degree of surface fluorine content up to a maximum, which depends on the degree of fluorination of the matrix used. The improved interaction between the fibre and the matrix is due to an enhanced compatibility at the fibre/matrix interface. KW - Adhesion KW - A. Carbon fibres KW - B. Debonding KW - B. Interfacial strength PY - 2007 U6 - https://doi.org/10.1016/j.compscitech.2007.02.012 SN - 0266-3538 VL - 67 IS - 13 SP - 2699 EP - 2706 PB - Elsevier CY - Barking AN - OPUS4-15814 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tran, M.Q. A1 - Ho, K.K.C. A1 - Kalinka, Gerhard A1 - Shaffer, M.S.P. A1 - Bismarck, A. T1 - Carbon fibre reinforced poly(vinylidene fluoride): Impact of matrix modification on fibre/polymer adhesion N2 - The quality of interfacial interaction is dictated by the surface chemistry of the carbon fibres and the composition of the matrix. The composition of poly(vinylidene fluoride) (PVDF) was modified by the addition of maleic anhydride grafted PVDF. The surface properties of the various matrix formulations were characterised by contact angle and electrokinetic measurements. Carbon fibres were modified by industrial electrochemical oxidation and oxidation in nitric acid, or the use of a traditional epoxy-sizing of industrially oxidised fibres. The surface composition, morphology and wetting behaviour of the carbon fibres was characterised. The interaction between modified PVDF and the carbon fibres was studied by direct contact angle measurements between PVDF melt on single carbon fibres and by single fibre pull-out tests. The best wetting and adhesion behaviour was achieved between PVDF containing 5 ppm grafted maleic anhydride (MAH) and epoxy-sized carbon fibres. The addition of MAH-grafted PVDF to the unmodified PVDF caused the apparent interfacial shear strength to increase by 184%. The apparent interfacial shear strength of this fibre–matrix combination allowed for the utilisation of 100% of the yield tensile strength of PVDF. KW - A. Carbon fibres KW - A. Coupling agents KW - B. Interface KW - B. Adhesion KW - Wetting PY - 2008 U6 - https://doi.org/10.1016/j.compscitech.2008.02.021 SN - 0266-3538 VL - 68 IS - 7-8 SP - 1766 EP - 1776 PB - Elsevier CY - Barking AN - OPUS4-18259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -