In-situ-generated fillers

In Situ-Generated Fillers Bicontinuous Phase Nanocomposites... 

Very little work has been done on elastomers in torsion. There are, however, some results on stress-strain behavior and network thermoelasticity [2,116]. More results are presumably forthcoming, particularly on the unusual bimodal networks and on networks containing some of the unusual in situ generated fillers described subsequently. 

In addition to the conventional technique of blending filler particles into the elastomer prior to cross-linking, reinforcement of rubbers has also been obtained by in situ generated filler particles. This technique uses the sol-gel method. 

J.E. Mark and D.W. Schaefer, Reinforcement of elastomers by the in-situ generation of filler particles. In D.W. Schaefer and J.E. Mark (Eds.), Polymer-Based Molecular Composites, Materials Research Society, Pittsburgh, 1990, Vol. 171, p. 51. 

Figure 8.4 Stress-strain isotherms for PDMS networks reinforced with in situ generated titania particles.39 Each curve is labeled with the wt % of filler introduced, and filled circles locate results used to test for reversibility.

These in situ generated silica fillers also give increased resistance to creep or compression set in cyclic deformations, as is illustrated in Figure 8.6.43 The in situ filled PDMS samples are seen to show very little compression set. They can also provide increased thermal stability, as demonstrated by the results presented in Figure 8.7. 44... 

Catalyst/reduction system/temp./reactive/inert atm. (in-situ generation of filler particles)... 

Electron microscopic results on networks filled in situ by the sol-gel approach have shown that the filler particles typically have a narrow distribution of sizes, with most diameters in the range 200-250 A. TEM studies on the distribution of silica in situ generated within PDMS have shown that well-distributed particles can be obtained by using basic catalysts, thin samples, and long hydrolysis times, while the silica was found to precipitate mainly in the sample periphery in the case of acidic conditions, bulky... 

The organization of this edition follows that of the earlier one. Part I (Chapters 1-3) provides an introduction to the types and properties of functional fillers and their polymer composites, including melt mixing aspects. Part II (Chapters 4-6) discusses different types of surface modifiers and coupling agents for fillers. Part III discusses in detail individual types of man-made, natural, in-situ generated and mineral fillers, and their functions. High aspect ratio fillers (Chapters 7-10), low aspect ratio fillers (Chapters 11-16), and a variety of specialty fillers for specific applications (Chapters 17-24) are included in Part III. Each filler chapter, typically, contains information on (a) production methods, (b) structure and properties, (c) suppliers, (d) cost/availability, (e) environmental/toxicity considerations, and (f) applications based on primary and secondary functions. 

In situ-generated silica fillers improve creep resistance and compression set in cyclic deformation. Ihe filled samples show very little compression set (figure 9.7). Thermal stability also improves as reflected by higher decomposition temperatures, (figure 9.8) A possible mechanism... 

Mark, J. E. Schaefer, D. W., Reinforcement of Elastomers by the In-Situ Generation of Filler Particles. In Polymer-Based Molecular Composites, Schaefer, D. W. Mark, J. E., Eds. Materials Research Society Pittsburgh, PA, 1990 Vol. 

Dorigato A et al (2013) Electrically conductive epoxy nanocomposites containing carbonaceous fillers and in-situ generated silver nanoparticles. Express Polym Lett 7(8) 673... 

Fig. 1.41. Mooney-Rivlin isotherms for PDMS elastomers filled with in situ-generated silica, with each curve labeled with the amount of filler precipitated into it [173]. Filled symbols are for results obtained out of sequence in order to establish the amount of elastic irreversibility, a common occurrence with reinforcing fillers. The vertical lines locate the rupture points.

Yuan Q W, Mark J E (1999) Reinforcement of poly(dimethylsiloxane) networks by blended and in-situ generated silica fillers having various sizes, size distributions, and modified surfaces, Macromol Chem Phys 200 206-220. 

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