Glass spheres, strength

Figure 2.2. Compressive strength of glass spheres as a function of their diameter...

Although glass spheres are classified as nonreinforcing fillers, the addition of 40 g of these spheres to 60 g of nylon 66 increases the flexural modulus, the compressive strength, and the melt index of the polymer. The tensile strength, the impact strength, the creep resistance, and the elongation of these composites are less than those of the unfilled nylon 66. 

Foams with polymeric microspheres have poor mechanical properties because the filler and binder have similar elasticities. Consequently the binder s strength is not reflected as clearly as it is when glass spheres are used. 

Reinforcement with particles such as chalk, quartz, mica and glass spheres, is frequently carried out with thermoplastics and thermosets to obtain a higher stiffness (and sometimes a higher strength). There is a gradual transition from high-quality to... 

Table 4, Shear strength values of schwarzsiegel and glass sphere at 4 and 15 bars...

Figure 8. Shear strength changes of glass sphere with saturation at 4 and 15 bar.

Microcel M borosilicate glass spheres in a density range from 0.18 to 0.35 g/cm which have a crushing strength of 6-15 MPa or 900-2200 psi Duke Scientific, Palo Alto, CA USA... 

Compressive strength, MPa 345 (AgCLAD, thick-waUed spheres coated with silver), 10-20 (Metalite, fight glass spheres coated with silver), 70 (Conduct-O-Fil)... 

ESR has been used to investigate the role of the filler-matrix Interaction in filled rubbers at cryogenic temperatures (10). The breakdown In adhesion between filler and matrix results In vacuoles or voids in the material. Figures 3 and 4 show a contrast In behavior for Sp glass spheres In rubber with and without a silicone coupling agent treatment. In the first case strength Is low and very few free radicals are produced... 

The modulus and strength of plastics can be increased significantly by means of reinforcement [25-27]. A reinforced plastic consists of two main components—a matrix, which maybe either a thermoplastic or thermosetting resin, and a reinforcing filler, which is mostly used in the form of fibers (but particles, for example glass spheres, are also used). 

---