Epoxy polymers strength

The Eq. (7.13) was used for the studied epoxy polymers strength (fracture stress) Oj. calculation. In Fig. 7.11 the comparison of strength values Op obtained experimentally and calculated according to the Eq. (7.13), for sulfur-containing epoxy polymers is adduced. As the adduced comparison shows, the good conformity of theory and experiment is obtained. 

FIG. 10 Compressive (a) yield strength and (b) moduli for the pristine epoxy polymer and the exfoliated epoxy-clay nanocomposites prepared from three different kinds of organomontmorillonites. (From Ref. 40.)... 

Netravali, A.N., Hcnstenburg, R.B., Phoenix, S.L. and Schwartz, P. (1989a). Interfacial shear strength studies using the single filament composite test, part I Experiments on graphite fibers in epoxy. Polym. Composites 10, 226-241. 

One can see that epoxy polymer concrete exhibits higher compressive strength, with values ranging from 3.8-4.3 times higher than commercial concrete. Compressive strength of this PC shows an increase of 1.5 times when glass fibers are added to the epoxy resin matrix and 2.0 times with the use of carbon fibers [8],... 

The ultimate compressive strength of drying epoxy polymer concrete samples is about 92% of the control sample strength, which testifies to a high degree of reversibility of the process associated with the adhesive nature of the interaction between binder and filler. 

Golestaneh, M., Amini, G., Najafpour, G. D., and Beygj M.A., Evaluation of Mechanical Strength of Epoxy Polymer Concrete with Silica Powder as Filler, World Applied Sciences Journal 9, no. 2 (2010) 216-220. 

Novel hydroxyurethane modifiers (HUM) for cold-cured epoxy composite materials were synthesized. It is established that the compositions with HUM demonstrate a significant increase in the speed of the curing process, a nontrivial increase in abrasion resistance, and a marked improvement in strength properties. The HUM, which possesses a wide range of hydrogen bonds, is embedded in an epoxy polymer network without a direct chemical interaction. 

A wide range of physical properties can be achieved by varying the molecular weight of the epoxy component, the type of hardener and by adding catalysts and plasticizers. Epoxy polymers can be reinforced with glass, carbon and synthetic fibres prior to curing to increase strength and flexibility. 

Hypotheses have been advanced to explain the increase of the impact strength of the epoxy resins by the integration of finely dispersed rubbers. There is an assumption [139] that the rubber particles in the epoxy polymer matrix absorb the impact energy in the manner of mechanical damping. In this case the dissipation of the excess energy occurs mainly inside the formed interphase layer with decreased density of the cohesion energy. In addition, to provide max-... 

From the above, one can conclude that for ERC with SKN-3KTR the conditions are met for maximal adhesion interaction between the epoxy polymer and the rubber due to the components compatibility. The maximal values of K c are determined for ERC obtained by the method with PER (Fig. 3.20). It should also be noted that these conditions ensure the higher adhesion strength of ERC (Fig- 3.21). Small additions of surfactant to ERC obtained by the method with PER allow additional improvement of their adhesion characteristics. 

H. Miyagawa, M. Misra, L.T. Drzal and A. K. Mohanty, Fracture toughness and impact strength of anhydride-cured biobased epoxy , Polym Eng Sci, 2005,45, 487-95. 

TBBA is cost effective and melt blendable in ABS, but it tends to lower the heat distortion temperature and the impact strength, as well as being vulnerable to UV. TBBA is used in epoxy polymers to make PCBs and can be converted to the bis-(2,3) dibromopropyl ether derivative, which is capable of meeting the requirements of UL-94 V-2 in high impact polystyrene and PP, despite its low bromine content. It is used in the US for wire nut connectors and in Christmas tree lights. TBBA is being subjected to assessments by various regulatory authorities. 

This phenomenon is in good correlation with corresponding composite mechanical strength. Of course the modified filler has more strong interactions (thanks to modifier) with epoxy polymer molecules, than uiunodified filler. 

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