Polymer-filler interactions observed effect with

An important feature of filled elastomers is the stress softening whereby an elastomer exhibits lower tensile properties at extensions less than those previously applied. As a result of this effect, a hysteresis loop on the stress-strain curve is observed. This effect is irreversible it is not connected with relaxation processes but the internal structure changes during stress softening. The reinforcement results from the polymer-filler interaction which include both physical and chemical bonds. Thus, deforma-tional properties and strength of filled rubbers are closely connected with the polymer-particle interactions and the ability of these bonds to become reformed under stress. 

An IR spectroscopy technique was developed to study the plasticiser migration from polymer compositions to the air environment. The applicability of the method was demonstrated for filled PVC compositions plasticised with di-n-butyl phthalate. Values for the effective diffusion coefficient(D) of the plasticiser were calculated from the spectroscopic data. An increase in the chalk content in a PVC composition led to a monotonic increase in D, whereas kaolin-filled compositions exhibited a more complex behaviour. The observed pattern of changes in D with varying filler content was correlated with the competing interaction of components in the system. 20 refs. (Full translation of Vys.Soed.B, 44, No.2, 2002, p.363-8)... 

The effect of technological additives on permeability of pol3Tuers is connected with variations in their sorption capacity, formation of defects and interactions of the electrolyte and additives. Impregnation of fillers improves, as a rule, permeability of polymers and intensifies clusterization of water and the penetrant. When polyethylene is filled by talc, HCl and H2O clusters formed in the polymer can be observed in microscope. Water and HCl sorption increases proportionally to the volume content of talc up to 17% concentration. Further increase in talc concentration does not result in sorption growth because of filler particle aggregation in the polymer binder. 

Complex viscosity data also shows how fillers interact with the matrix. Figures 9.19 and 9.20 show the effect of filler loading on the complex viscosity of two polymers (PP and PPS). Two conclusions can be drawn from these figures polymer type affects the rate of viscosity increase and the increase of viscosity is not proportional to the concentration of filler. Figure 9.21 shows that viscosities of polypropylene loaded with 10 and 20% calcium carbonate are almost identical whereas a large increase in viscosity is observed on addition of 40% calcium carbonate. ... 

The authors also describe the effect of temperature on the Payne effect. With increasing temperature the amplitude of the Payne effect decreases significantly (Fig. 12). Very surprisingly, enhanced Payne-like behavior was observed for rubber vulcanizates at room temperature where filler-filler and filler-polymer interaction are not observed in comparison to the typically filled vulcanizates. The authors concluded that in addition to the contribution from the filler-filler network, there are many other factors that affect the nonlinear viscoelastic behavior. Nevertheless, the Payne effect is assumed to arise from the elementary mechanism consisting of adsorption-desorption of polymer chains from the surface of the particles [50]. Besides the experimental investigation, the authors have applied the Maier... 

The authors concluded that the drop in storage modulus with applied strain is found to be higher for ACM/silica nanocomposites and lower for PVA/silica systems. For all measured nanocomposites, this effect is higher with increasing temperature. The reported observations are consistent with relatively weaker polymer-filler bonding in ACM/silica and stronger interactions (matrix vs filler) for ENR/silica and PVA/silica nanocomposites [18]. 

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