Matrices epoxy

Dynamic mechanical testing of the epoxy matrix/epoxy sizing blends was done on a DuPont model 983 DMA interfaced to a 9900 model controller. Stoichiometric mixtures of DER 383 and DACH were first prepared, and then sufficient size was added to produce the desired concentration on a weight percent basis. The mixture was degassed and poured into silicone RTV-664 [10] molds that contained four cavities, 3.2 x 12.5 x 60 mm. The specimens were cured at room temperature for 16 h in a desiccator, placed in a forced convection oven, and ramped to 80°C at 5°C/min and held at that temperature for 2 h. The samples were allowed to cool to room temperature and then removed from the mold. The specimens were replaced in the oven on a metal sheet and postcured at 175°C for 2 h. The free surface of the specimens was ground on a Struers Abramin polisher using 320 grit SiC paper and water to produce parallel faces on the specimens. 

The bonded assemblies were produced using two adhesives. The first, which will be discussed in more detail here, is the matrix epoxy resin employed either to bond the composite adherends (in the case of lap shear and L specimens) or to overlaminate onto a balsa sandwich or monolithic composite base in the case of top hat specimens. The second is a more ductile epoxy resin (Redux 420), used to bond the composite adherends. Figure 1... 

Table 7.2 Matrix epoxy resin systems and iayup repeat value in [0/ 45/90°]x, iayup for Karasek et al. [66] iaminates...

Relaxation properties of epoxy rubber compounds and mechanisms of the rubber strengthening effect. Usually ERC displays two regions of relaxation. The first is at a temperature much higher than room temperature and depends on the glass-transition of the matrix (epoxy) component of the compound. The glass-transition of the rubber phase is related to the second relaxation region, which is detected at temperatures below room temperature. 

Epoxy, bisphenol / /epichlorohydrin resin, thermosetting matrix Epoxy, bisphenol / /epichlorohydrin resin, toners... 

Carbon fibers are especially used in the production of highly stressed construction materials, in combination with a matrix (epoxy resin, phenolic resin) and for the production of high-strength sports equipment (golf clubs, tennis racquets, skis). If a further reduction can be achieved in production costs, then a whole new field of application could open up, especially in the automobile industry. 

Fig. 7. Infrared Contour Maps of a liquid crystal specific peak left, bottom) and a matrix (epoxy) specific peak right, bottom) of a PDLC droplet, whose polarized optical image is shown top, left) with the corresponding orientation visualized top, right) (from Ref [87])...

Thermal analysis by differential scanning calorimetry on as-received materials indicated that the matrix epoxy was not fully cured an exotherm was detected during the first scan from room temperature to 573K (300°C). A... 

The polymerization in situ (together with a filler) is often applied as a method for receiving nanocomposites. The matrix epoxy polymer cross-linking process both in nanofiller (Na+ - montmorillonite) presence and without it was studied within the framework of a strange (anomalous) diffusion conception [51,52]. A nanocomposites epoxy polymer/ Na+ - montmorillonite (EP/MMT) cross-linking was made at temperatures 353, 373 and 393 K, cross-linking of EP - at 393 K [53]. 

The properties presented in Table 5.3 are representative of what can be obtained at room temperature with a well made PMC employing an epoxy matrix. Epoxies are widely used, provide good mechanical properties, and can be considered a reference matrix material. Properties of composites using other resins may differ from these. This has to be examined on a case-by-case basis. 

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