Epoxy SINs

Epoxy-sin-butyl acrylate, 266 Epoxy-sin-ethyl acrylate, 265... 

Lap-shear studies for several polyurethane-epoxy SINs and semi-SINs are reported in Figure 7.17. A distinct maximum in lap-shear strength is noted at midrange compositions. By contrast, the peel strength shows a... 

Figure 7.17. Lap-shear (psi) vs. network composition for polyurethane/epoxy SINs SIN-I (open circles) SIN-II (triangles semi-SIN (filled circles) SIN-III (crosses).

Armstrong Cork Company, Improvements in or Relating to Adhesive Compositions, Br. Pat. 784,565 (1957). NBR-sulfur/phenol-aldehyde-epoxy SINs. High peel strength adhesives. 

Technique, J. Dental Res. 53(3), 1074 (1974). IPNs as denture-base materials. Celanese Coatings Company, Resin Compositions, Br. Pat. 1,205,682 (1970). Unsaturated polyester-styrene/epoxy SIN. 

H. L. Frisch, R. Foreman, R. Schwartz, H. Yoon, D. Klempner, and K. C. Frisch, Barrier and Surface Properties of Polyurethane-Epoxy Interpenetrating Polymer Networks. II, Polym. Eng. Sci. 19(4), 294 (1979). Polyurethane/epoxy SINs. Contact angles of drops of methanol mixtures on polyurethane/epoxy interpenetrating network films. Transmission of vapors in polyurethane/epoxy SINs. 

K. C. Frisch, D. Klempner, S. K. Mukherjee, and H. L. Frisch, Stress-Strain Properties and Thermal Resistance of Polyurethane-Polyepoxide, Interpenetrating Polymer Networks, J. Appl. Polym. Sci. 18(3), 689 (1974). Polyurethane/Epoxy SIN. Tensile strength. Heat resistance. 

Westinghouse Electric International Co., Improvements in or Relating to Resinous Compositions, Br. Pat. 794,541 (1958). Unsaturated polyester-styrene/epoxy SINs. Low-shrinkage resins. 

Whitney solved Equations (6.44) for a square four-layered symmetric cross-ply [0 /90 /90 /0 ] laminated graphite-epoxy plate under the transverse load p = Po sin(7tx/a) sin(jiy/a) [6-30], The material properties are typical of a high-modulus graphite-epoxy ... 

Figure 6-22 Deflection of an infinite Two-Layer Cross-Ply Graphite-Epoxy Strip under po sin(ro(/a) (After Whitney [6-30])...

Epoxy re.sins, ubiquitous in the electronics industry, are used in a wide variety of applications in the manufacture of electronic components, including insulation materials, circuit board substrates, and component coatings and encapsulants. 

A novel approach to IPN synthesis was reported by Sperling and Arnts (I). They synthesized two polymer networks by simultaneous yet independent reactions in the same container at the same time. Complicated interactions were eliminated in the SIN s by combining free radical (acrylate) and condensation (epoxy) polymerization. The present work uses the basic technique of Sperling and Amts. 

The length of time the epoxy could prereact was limited at the high end by the gel time of the epoxy which was about 14 hr. The concentration of DEGDM was varied between 0 and 1.6% based on n-butyl acrylate. (Note that 0% DEGDM content produces a semi-SIN.) The ranges of all variables were preselected so that the reactions were most nearly simultaneous in rate when the variables were at the midpoint of their experimental ranges. The experimental conditions are given in Table I. 

The most important results were observed in the glass transition behavior of the materials where increasing the epoxy prereaction time increased the glass transition of the epoxy-rich phase (Figure 8). At an epoxy prereaction time of about 1 hr, Tgl was 97 °C which was lower than the glass transition of the pure epoxy, 105°C. However when the epoxy prereaction time was increased, Tgl also increased. When the epoxy prereacted for 6 hr, the SINs Tgl was 105°C or nearly the same as that of the epoxy homopolymer. Surprisingly, for eleven hours prereaction time the SINs Tgl was 115°C or higher than that of the pure epoxy. The differences in T. i from 97° to 115°C could not readily be accounted for by experimental error. Replication of the center point showed that the experimental error was only about 2°C. 

Stress-Strain Studies. Stress-strain analysis showed that most SIN samples had tensile strengths greater than that of the epoxy homopolymer (Figure 11). The pure epoxy resin has a tensile strength of ca. 6700 psi, and the tensile strength for the SIN s ranged from ca. 6400-8900 psi. 

The SINs all exhibited modest increases in impact strengths. The impact strength for the pure epoxy was 0.16 ft-lbs/in., while the impact strength of the SIN s ranged from 0.21-0.33 ft-lbs/in. However experimental error was significant when compared with the range of the impact strength for the SIN. Consequently no valid trends could be established other than the modest increases already described. 

Another explanation of the increase in the major glass transition 126) of SIN s relates to the retention of low molecular weight polymer of one component by the other phase. In this case low molecular weight fractions of the epoxy may be trapped in the rubber. When the epoxy is at its gel point, there is still much low molecular weight epoxy resin that has not reacted. At the point when the n-butyl acrylate is still mostly... 

In SIN formation, both timing and rates of polymerization to form the two networks are important. With an acrylate-epoxy system, it was found that simultaneous gelation produced materials with poorer properties than those formed by slightly mismatched polymerization rates (6). In another instance (7), polyurethane-poly(n-butyl methacrylate) SINs in which the acrylate was initiated photolytically at various times after the onset of polyurethane formation produced a series of materials, presumably with the same chemical composition, with an average particle size that decreased as the delay time to acrylic initiation increased. Damping properties of these materials changed systematically across the series. 

Bisphenol A type epoxy resin (Epikote 828 Shell) cured with modified amine (Epomate B002 Shell) was used as the matrix of the dismantlable adhesive (re-sin/matrix=2 1 w/w). Fig. 34.3 shows their chemical structures. The bulk adhesive was cured at room temperature for 24 h before the experiments. Cured bulk resin mixed with the microcapsules was used for the specimens to measure the volume change. 

Scarito and Sperling (14). The impact strength of the modified SIN system was indeed improved, but the glass transition temperature of the composite decreased substantially relative to the epoxy control. 

A study of compatible simultaneous interpenetrating polymer networks (SINs) of diallyl phthalate and (diglycidyl ether of bisphenol A)-based epoxy resin [134],... 

The electrical conductivity of carbon fiber composites is affected by the fiber type, density, and waving pattern. Several authors have demonstrated electrical conductivity in carbon fiber composites and measured resistance for a range of composite types. For example, carbon fiber-epoxy has a resistivity ranging from 5000pf2cm to 20,000 pH cm [104,105.110]. It has also been shown that carbon fibers in matrix composites produce a transverse electrical conduction path [112]. Eddy currents flow along fibers and pass from one fiber to another at the points of fiber contact, as shown in Fig. 8. The longitudinal and transversal resistivity of carbon fiber reinforced epo.xy re,sin for a volume fraction of 50% is 0.009 - cm and 0.5 cm respectively [112]. Further detailed infom-... 

MYLAR, PLAIN fTOTAL IDMILSl MYLAR. SANDBLASTED, EPOXY VERSAMIO RE SIN SYSTEM MILS TOTAU ACLA R 33C (S MILS)... 

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