Delamination resistance

Davies, P. and Moore, D.R. (1990). Glass/nylon-6.6 composites Delamination resistance testing. Composites Sci. Technol. 38, 211-227,... 

Chan, W.S. (1991). Design approaches for edge delamination resistance in laminated composites. J. Composites TechnoL Res. 14, 91-96. 

Liu, D. (1990). Delamination resistance in stitched and unstitched composite plates subjected to impact loading. J. Reinforced Plasi. Composites 9, 59-69. 

Masters. J.E. (1987a). Correlation of impact and interleaf delamination resistance in interleaved laminates. In Proc. 6th Intern. Conf. Compo.site Mater. (ICCM-VI) (F.L. Matthews et al.. eds), Elsevier Appl. Sci.. London, pp 3.96-3.107. 

Masters, J.E. (1989). Improved impact and delamination resistance through interleaving. Key Eng. Mater. 37, 317-348. 

The comparison of the different initiation points in the three laminate types (Tables 2-4) raises the question which definition shall be used for initiation in the cross-ply laminates. Since visual initiation (VTS-point) and probably also non-linearity of the load-displacement plot (NL-point) yield values similar to initiation values in the corresponding unidirectional laminate, the maximum load or 5% offset in compliance (MAX/5%-point) seems to reflect the higher delamination resistance of cross-ply compared with unidirectional laminates better. Further analysis of additional data from the 3" round robin may allow a better assessment of this question. 

Fig 3 Apparent delamination resistance curves of representative specimens, the position of the pinned areas is shown by the dashed lines. 

Exploratory tests with a higher loading rate of 5mm/min (maximum allowed by ISO 15024) were conducted on two SO.5/0.5 and one S2/2 specimen in order to check for indications of loading rate effects. In Fig. 6, the dashed lines show the apparent delamination resistance curves of specimens tested at a loading speed of 5mm/min, the full lines the resistance curves of the specimens tested at 2mm/min. The S2/2 specimens are represented by filled circles,... 

Fig 6 Comparison of the apparent delamination resistance with the different loading rates... 

In most cases, the substrates are metals, such as copper, aluminum, etc. The pretreatment of the metal substrate is critical to its performance. In some cases, a primer is applied to impart adhesion, corrosion, and delamination resistance. 

The properties of filled materials are eritieally dependent on the interphase between the filler and the matrix polymer. The type of interphase depends on the character of the interaction which may be either a physical force or a chemical reaction. Both types of interaction contribute to the reinforcement of polymeric materials. Formation of chemical bonds in filled materials generates much of their physical properties. An interfacial bond improves interlaminar adhesion, delamination resistance, fatigue resistance, and corrosion resistance. These properties must be considered in the design of filled materials, composites, and in tailoring the properties of the final product. Other consequences of filler reactivity can be explained based on the properties of monodisperse inorganic materials having small particle sizes. The controlled shape, size and functional group distribution of these materials develop a controlled, ordered structure in the material. The filler surface acts as a template for interface formation which allows the reactivity of the filler surface to come into play. Here are examples ... 

Blends of ABS with commercial polyamides such as polyamide-6 and -66 are highly incompatible due to their dissimilar polarity. Such simple blends of ABS and PA exhibit poor delamination resistance and have no practical value. Recent efforts to improve the compatibility led to several different approaches. 

Key to the successful compatibilization involves the formation of a graft copolymer of SAN and PA at the interface, which reduces the interfacial tension and improves the interfacial adhesion. Blends with stable, dispersed morphology are achievable. They exhibit high delamination resistance and toughness. 

Because of their highly polar and hydrogen bonded structure of the backbone, as a general rule polyamides are immiscible with most of the commercially known polymer systems. In addition, the high degree of interfacial tension [Wu, 1989] between polyamides and other classes of polymers leads to highly phase separated blends with poor delamination resistance. Hence simple blends of PA with other commercial polymers generally do not have any practical value. 

Molecular condensables Phthalates, organophosphates, silicones, siloxanes Outside air, air filters, sealants, adhesives, flame retardants, FOUPs, gaskets Delaminates resist and ARC films... 

ISO 15.024. Determination of Mode I delamination resistance of unidirectional fibre-reinforced polymer laminates using the double cantilever beam. 

Fracmre mechanics tests that quantify the delamination resistance of FRP composites determine the rate of change in strain energy per unit area of delamination (i.e. the... 

Strain energy release rate, which is the driving force for delamination propagation and denoted by the symbol G) [1,4]. Assessment of the long-term performance of FRP composites for aerospace apphcations requires consideration of the effects on their delamination resistance of both service loads and environmental exposure. 

Mode I cyclic compression—compression tests on CFRP-impacted CFRP plates have been performed by Katerelos et al. [38]. The analysis relies on nondestructive testing (ultrasonic C-scan) and modelling for quantification of delamination resistance. In mode II tests, there is a choice between test parameters yielding no shear reversal or... 

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