Glass Fiber Reinforced Polyester Resin Research Articles

Poliflexsol polyester resin: It's properties and applications to conservation

Abstract Poliflexsol is a light curable, glass fibre reinforced polyester resin supplied in sheet form. Since sheets of Poliflexsol are contained between two nylon films, the resin is clean and easy to handle. Its high flexibility allows it to be shaped as required and this has led to its application as a support material. The purpose of this paper is to present the results of an investigation into the properties of Poliflexsol and to describe three examples of its use both on and off‐site. Poliflexsol undergoes minimal shrinkage on curing and ageing and is suitable for use with metals and organic materials.

ＧＦＲＰの加熱切削

In order to reduce the tool wear in cutting GFRP, turning of both pipe and disk of GFRP and drilling of a GFRP plate were carried out under the condition of elevated temperature below 423 K. The pipe was the unidirectional glass fiber reinforced polyester resin, and the disk as well as the plate was the glass cloth reinforced epoxy resin. Both the mechanism of reducing the tool wear and the influence of the cutting temperature on it are considered from the experimental results. The reducing effects of tool wear range from the low cutting speed inducing the relative small tool wear to the high cutting speed inducing the large tool wear directly proportional to the cutting speed. This is based on the decrease of the shear strength and the hardness of the glass fiber, and the decrease of the viscosity of matrix. However, as the bonding between the glass fiber and the matrix also becomes weak at elevated temperature, the condition of the cut surface is not good in many cases. The cemented carbide P 10 showed the remarkable increase of tool wear even at 373 K in heating the tool itself. Consequently, in cutting GFRP with the carbide tool, it is considered that the cutting heat has the two effects, that is, the one is the reducing effect of tool wear due to the variation of the mechanical properties of workpiece, the other is the promoting effect of the tool wear due to the decrease of hardness of the bonding phase of carbide tool and these two effects cancel out. In case of coating tool, the flank wear width decreases with increase of cutting speed. This differs from the case of the cemented carbide tool, the cermet tool and HSS tool.

Temperature dependence of hydrothermal ageing of CSM-laminate during water immersion

Random glass fibre reinforced polyester resin specimens were exposed to hot water at different temperatures. Effects of the environmental history on strength characteristics of the composite were investigated using the three-point bend tests. The study shows that reduction of the strength of random-fibre composites due to hydrothermal effects is a rate process for which the temperature influences only the rate constant. The rate constant follows the Arrhenius equation 1/τ = 1/τ 0 exp [−E/RT], where 1/τ is the rate constant, E and R are activation energy and gas constant respectively; τ 0 is a constant and T is absolute temperature. The time/temperature superposition principle is applicable for the degradation process and a master curve for strength can be obtained by shifting the data along the logarithmic time scale by a shift distance, ln a D. This allows the estimation of strength at any temperture from experiments conducted only at one temperature.

Glass fibre reinforced polyester resins: (Duse, D. of Italy) GB 2 158 079A (6 November 1985)

Glass fibre reinforced polyester resins: (Duse, D. of Italy) GB 2 158 079A (6 November 1985)

Environmental and time dependence of fracture toughness and crack growth in glass-fibre reinforced polyester resins

The validity of simple (maximum load) fracture toughness testing of glass-fibre reinforced polyester resin laminates has been examined for SEN specimens using “slow strain rate” test techniques developed for metallic materials. Laminates were tested both in air and whilst immersed in an acidic environment. In general, valid test conditions were only established at test speeds <10−2 mm min−1 which are slower than those generally reported in the past. Fracture toughness was found to be greatly reduced by the presence of the chemical environment, as would be expected from the known sensitivity of these materials to environmental stress cracking. The slow strain rate test technique indicated a threshold level of critical stress intensity for environmental stress cracking and hence could be useful in ranking materials. Environmental effects were also found to determine crack growth rates as measured on DCB specimens. Crack growth data was analysed in terms of initial and/or inherent flaws and its use in predicting creep-rupture life examined. In principle it was concluded that use of crack growth data could provide an alternative to the present qualitative approach to design and a more predictable alternative to long term creep-rupture testing.

The microstructure of glass fibre reinforced polyester resin composites

SUMMARYThe microstructure of a composite material is commonly defined by the volume fraction occupied by the fibres. An attempt is made to gain a more quantitative definition of the microstructure of unidirectional glass fibre reinforced polyester resin using data derived from a Quantimet 720 Image Analysing Computer.Sections to be examined under the Quantimet were cut perpendicular to the fibre direction and polished and etched such that the fibres appeared black. Values of the area covered by the fibres inside a small test cell, moved around the cross‐section in a contiguous grid, were determined; values for larger cells, made up of several adjacent test cells, were calculated from these.Two methods of analysis are presented. The first method involves the determination of the variance of the values of fractional area covered for different cell sizes. Information regarding the nature of the fibre distribution is sought both from comparing the variance values with those predicted for the null hypothesis, a random distribution, and from examining the shape of a surface defined by a variance matrix.The second method of analysis is based on the concept that a structure may be defined by its relationship to a structuring element. In the present case, structuring elements are squares and rectangles of empty space; the probability of finding such empty space is estimated. Information regarding the nature of the fibre distribution is sought from the probability matrices.

The development of a damage zone at the tip of a crack in glass fiber reinforced polyester resin

The development of a damage zone at the tip of a crack in glass fiber reinforced polyester resin

Work of fracture of fibre-reinforced polymers

The work of fracture has been measured by bending tests on notched specimens of graphite and glass fibre reinforced polyester resins. Fibre bundles were used to increase the effective fibre diameter and improve the uniformity of the fibre strength.

Some aspects of the evaluation of the impact behaviour of low temperature fibre composites

Miniature Charpy impact and ballistic impact equipment is described and its use exemplified. Ballistic impact studies of glass fibre reinforced polyester resin and boron reinforced aluminium highlight the complex damage mode in composites. Failure criteria used in the evaluation of metals are no longer applicable to composites. Glass fibre reinforced polyester resin composites are damaged by internal delamination at energy levels which result in negligible surface damage. The bend strength is markedly reduced by this damage whilst the tensile strength, although not to the same degree, is also affected significantly. Similar behaviour is noted in the boron reinforced aluminium composite system but is shown to be related to filament damage not delamination. The composites, particularly boron reinforced aluminium, are markedly inferior than homogeneous metals in impact strength. It is proposed that this behaviour may well be an inherent property of composites reinforced with uniformly distributed small diameter brittle fibres.