Effect of Colloidal Silica on Adhesion of Glass Fibres to Polypropylene

Abstract

Colloidal silica was used to treat glass fibres to improve their adhesion to polypropylene resin (PP). The glass fibres were also treated with a coupling agent and maleic anhydride modified polypropylene emulsion (MAPP) to enhance their interfacial bonding. The surfaces of the glass fibres were observed by scanning electron microscopy (SEM). Because colloidal silica made the surfaces of the glass fibres rougher, PP could anchor on the surface of glass fibres to improve the fibre/PP bonding. These results were proved by using a microbonding pull-out test. The composites of glass fibres and PP were fabricated by means of a twin screw extruder and an injection moulding machine. The tensile strength and flexural strength were determined and the fracture surfaces were observed by SEM to establish the contribution of the surface treatment. The test results demonstrate that the tensile strength of the composites reinforced by those glass fibres treated with colloidal silica first and then with coupling agent and MAPP was 73.4% higher than that of composites reinforced with untreated glass fibres, and 24.0% higher than that of composites without colloidal silica but still treated with coupling agent and MAPP. As for the flexural strength, the colloidal silica, coupling agent and MAPP-treated composite was 75.9% stronger than the untreated ones and 22.3% stronger than materials without colloidal silica but treated with both coupling agent and MAPP.

Effect of Fiber Surface Texture Created from Silane Blends on the Strength and Energy Absorption of the Glass Fiber/Epoxy Interphase

“…Figure 10 also shows that the fiber treated with the GT13 silane blend undergoes a significant drop in the interfacial shear strength when compared to the GT31 and GT11 silane blends. There are two possible reasons for the decrease in the IFSS in GT13: (1) there is no significant change on the glass fiber surface roughness due to the large amount of TEOS which composes the siloxane network; (2) the large molar fraction of TEOS in the silane blend may possibly result in the formation of weak and brittle aggregates that can be sheared off relatively easily, which does not contribute to an improvement of the interfacial shear strength.…”

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Most of the research to date has focused on tailoring the interphase adhesion by controlling the degree of chemical bonding between fiber and resin. The interfacial shear strength (IFSS) has been increased as much as 40% by modified chemical surface bonding [1][2][3]. However, it is well known that increasing the interfacial strength of the fiber reinforced polymeric composite material often leads to a reduction in the fracture toughness and vice versa [4][5][6][7][8][9][10][11][12].

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Flexural and Charpy impact behaviour of epoxy/glass fabric treated by nano-SiO2 and silane blend

“…It has been reported that increasing the adhesion strength of the fibre-reinforced polymeric composite material often leads to a reduction in the toughness of the composite material. A large body of these researches has focused on the effect of interfacial chemistry on fibre–matrix adhesion [2, 11, 14, 15, 22], and a limited amount of research has assessed the influence of glass surface texture [5, 18, 21, 23, 24].…”

Effect of fiber surface texture on the mechanical properties of glass fiber reinforced epoxy composite

“…resin, which has been reported to increase the interfacial shear strength (IFSS) up to 40% [1][2][3]. However, it is well known that increasing strength often leads to a reduction in energy absorption and vice versa [4][5][6][7][8][9][10][11][12].…”