Glasses difference from bulk

When a craze occurs around a rubber droplet the droplet is stressed not only in a direction parallel to the applied stress but also in the plane of the craze perpendicular to the applied stress (see Figure 3.9). Such a triaxial stress leading to dilation of the particle would be resisted by the high bulk modulus of the rubber, which would thus become load bearing. The fracture initiation stress of a polyblend should not therefore be substantially different from that of a glass. 

The surface of a solid may differ in many ways from its bulk composition. Especially, such solids as commercial carbon black may contain minor amounts of impurities (such as aromatics, phenol, carboxylic acid). This would render surface adsorption characteristics different from that of pure carbon. It is therefore essential that, in industrial production, quality control of the surface from different production batch is maintained. Otherwise, the surface properties will affect the application. Another example arises from the behavior of glass powder and its adsorption character for proteins. It has been found that if glass powder is left exposed to the... 

Gross dissolution of the waste can be measured from the loss of weight of the sample or by determination of the appearance in the leaching medium of the major matrix constituent e.g. glass). However, the selective leaching of important fission product elements has been observed in this work to be significantly different from that of the bulk waste matrix. The units normally used to describe leach rates, g/cm day, appear to imply... 

The theory has been examined by measuring the ratio K,c/Klcs as a function of j/g, as shown in Fig. 17. The theoretical lines have been fitted to the experimental points by choosing suitable values of the critical distance, c, which is the only fitting parameter. The agreement between theory and experiment has been found to be equally good for many different epoxy polymers cured with many different hardeners, both unmodified 44- 45,51), rubber-modified 45) and containing glass particles 22) and even, under certain circumstances, for structural adhesive joints S3). Values of critical stress, ct,c, and distance, c, for various epoxy materials, obtained from bulk and... 

One optical imaging technique that circumvents the problem of multiple fight scattering is to estimate the bubble size distribution from the area individual foam bubbles occupy ai a glass surface. Such experiments, and the systematic differences between bulk and surface bubble distributions, have been reviewed. Another technique that also directly measures the bubble size distribution is ihe use Of a Coulter counter, where individual bubbles are drawn through a small lube and counted. This yields a direct measure of the bubble size distribution, hut it is invasive and cannot probe the structure of the foam. 

The interfacial region modified by the silane has properties different from those of the bulk polyethylene. The crystallization in the interphase will be hindered due to the chemical bonds between the azidofunctional group and the polyethylene chains. Figure 6 shows this effect by a decrease of the heat of fusion (AH) with increasing number of silane layers for the composites with 20 and 50 vol% of glass. The AH values in Fig. 6 are in J/g polymer and were calculated from the values... 

---