Model filler studies

The temperature dependence of the Payne effect has been studied by Payne and other authors [28, 32, 47]. With increasing temperature an Arrhe-nius-like drop of the moduli is found if the deformation amplitude is kept constant. Beside this effect, the impact of filler surface characteristics in the non-linear dynamic properties of filler reinforced rubbers has been discussed in a review of Wang [47], where basic theoretical interpretations and modeling is presented. The Payne effect has also been investigated in composites containing polymeric model fillers, like microgels of different particle size and surface chemistry, which could provide some more insight into the fundamental mechanisms of rubber reinforcement by colloidal fillers [48, 49]. 

The data in Figure 2 clearly show that the phenolic model compounds studied here are more reactive than monomeric phenol under standard phenol formaldehyde reaction conditions. This is not surprising, since a wealth of literature shows the phenols substituted with electron donating groups are more reactive than unsubstituted phenol (12-14). However, it is particularly important for these complex phenolic-rich pyrolysis oils. These results suggest that the pyrolysis oil phenolic will react rapidly under standard cooking conditions and become covalently bound into the polymer networic. This means that the pyrolysis oils contribute to the strength of the network and do not simply act as fillers or extenders. 

Study waxes ie, waxes for carving, are useflil in the study and modeling of tooth forms and the teaching of anatomical detail. Carving wax compositions include paraffin, ceresin, ozokerite, camauba wax, montan waxes, and Acrawax C. Fillers and pigments may be added. 

Kumar et al. have studied the miUing behavior of brominated isobutylene-co-p-methyl styrene (BIMS) and its blends with EPDM [40]. Using the theoretical model of Tokita, they have tried to optimize the rmU parameters. They measured the critical nip-gap at which a front-to-back roll transition takes place. They concluded that addition of different fillers reduced the critical nip-gap for BIMS as compared to the gum polymer. The critical nip-gap is lower for systems containing... 

Applications The general applications of XRD comprise routine phase identification, quantitative analysis, compositional studies of crystalline solid compounds, texture and residual stress analysis, high-and low-temperature studies, low-angle analysis, films, etc. Single-crystal X-ray diffraction has been used for detailed structural analysis of many pure polymer additives (antioxidants, flame retardants, plasticisers, fillers, pigments and dyes, etc.) and for conformational analysis. A variety of analytical techniques are used to identify and classify different crystal polymorphs, notably XRD, microscopy, DSC, FTIR and NIRS. A comprehensive review of the analytical techniques employed for the analysis of polymorphs has been compiled [324]. The Rietveld method has been used to model a mineral-filled PPS compound [325]. 

One of the perspective ways of search of effective inorganic filler-catalysists for complex polyesters is kinetic study of the reesterification model reaction, performed in the presence of various inorganic compounds [1]. Such method allows to use the obtained results in the synthesis process of the filled complex polyesters [2],... 

Where Gp and GF are the shear moduli of the plastic matrix and the filler respectively, v is Poisson s ratio of the matrix, and V is the volume fraction. E s are Young s moduli. Recently this relation was verified for the rubber-reinforced thermoplastics (29). The effect of adhesion at the rubber-resin (or rubber-filler) interface has been studied (49, 57, 58) with mathematical models. 

X-ray diffraction measurements were used to determine the orientation of talc and lead carboxylate fillers in plasticised PVC extrudates. Correlations between the extrusion conditions (draw ratio and temperature), the development of filler particle orientation and the tensile properties of the plasticised PVC were studied. The presence of fillers enhanced Young s modulus and this was predicted well by the model developed by Halpin and Tsai. The extrudates were stretched above and below the gel-liquid transition temperature of PVC (about 205C). Above this temperature, the PVC could be stretched more and the tensile results indicated that the crystallites which were surrounded by more flexible chains were more oriented. 24 refs. 

Fig. 25 The 13C NMR signal in CDC13 of C60, in the absence and presence of the nanotubes (left). Looking down the axis of a space filler model of the nanotube (centre). Looking laterally at a ball and stick model of the helix, as found in the molecular modelling studies (right). AMI semi-empirical level using Hyperchem package the starting geometries for the nanotube and fullerenes were obtained from X-ray data for the free nanotube and the free fullerene and convergence criterion was 0.01 kcal A 1 mol-1...

A generalized kinetic model of cure has been developed from the aspect of relaxation phenomenon. The model not only can predict isothermal and non-isothermal cure curves using modulus and viscosity data, but also allows us to take into account the effect of filler on cure behavior. The prediction of viscosity and modulus values during the cure cycle allows one to preprogram cure in order to improve the material processing and end-product performance. The important findings of this study... 

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