Natural fillers

Table 1. Effect of filler nature, dispersedness and concentration on the degree of crystallinity of polyisobutylene samples [105]...

The increased lifetime expected from reinforcement by particulate fillers naturally refers to cured pieces. The incorporation of reinforcing fillers greatly... 

Fillers - natural cheaper substances such as chalk, talc and clay are incorporated to improve strength and lower the cost of the raw materials by increasing their overall bulk. 

NR composites and nanocomposites can be fabricated by three main techniques, namely latex compounding, solution mixing and melt blending. A variety of nanofillers, such as carbon black, silica, carbon nanotubes, graphene, calcium carbonate, organomodified clay, reclaimed rubber powder, recycled poly(ethylene terephthalate) powder, cellulose whiskers, starch nanocrystals, etc. have been used to reinforce NR composites and nanocomposites over the past two decades. In this chapter, we discuss the preparation and properties of NR composites and nanocomposites from the viewpoint of nanofillers. We divide nanofillers into four different types conventional fillers, natural fillers, metal or compound fillers and hybrid fillers, and the following discussion is based on this classification. 

The data of paper [4] for nanocomposites based on industrial isotactic polypropylene (PP) of manufacture Shell Co. is used. As a filler natural clay Na -montmorillonite is used modified by four modificators, with volume contents cpy=0.025, 0.050 and 0.10. The more detailed description of nanocomposites in paper [4] is cited. Specimens for mechanical testing in the form of dog-bone with base lenght 10 mm and thichness 0.2 mm were produced by pressing from the melt at 473 K. The tension testing was made at temperatures 293 and 373 K... 

Filler Natural Carbon fiber Glass fiber... 

In multicomponent PP systems containing a filler and two polymers, a special morphology may form in which one of the pol)oner components encapsulate the filler. Naturally, such a structure is accompanied by significantly modified interaction and properties [4]. 

Fillers reduce permeability as a consequence of their own impermeability. Replacement of the polymer by filler naturally results in a reduced permeation rate. Some fillers, notably those with a platy shape (fine clays and talcs) have a considerable influence on permeability [39]. These fillers work by forcing the fluid to take a longer path around the plates to escape from the opposite side of the membrane. In addition, the plates reduce the effective area through which the fluid may pass. Thus, the net result is the same as if a thicker membrane of smaller area were used (Figure 7.5). 

Additives used in final products - Fillers carbon fiber, glass fiber, mineral fillers, natural fibers ... 

See carbon black, carbon materialcolloidal carbon, filler, natural graphite, particulate carbon, soot... 

Despite the importance of extensional viscosity studies in filled-poljrmer processing it is unfortunate that the effects of various factors like size distribution of the fillers, nature of the surface, flocculation, etc. as in the case of shear viscosity (section 4.2), has not been studied at all. Only the effect of the shape of the filler on the extensional viscosity has been brought out by Nicodemo et al. [177]. A lot more research in this area is thus warranted. The main reason for the dearth of information in this area is probably due to the absence of a cheap and simple apparatus for the measurement of extensional viscosity. Most of the workers have had to design their own apparatus for determining extensional viscosities depending on the system to be measured and the facilities available. 

The value of the interaction parameter in the siuface layers depends on the filler nature (on its activity) at comparable specific surface. Not all fillers increase thermodynamic stability of the filled alloy. It is also evident that the effect depends on the conditions of the alloy production. Theoretically, the effect of the surface on the behavior of polymer mixtures was considered by Nooland. ... 

This law describes an ideal case of steady flow which is strongly influenced by the nature of polymer, crosslinks, plasticizers, fillers, nature of penetrant, and temperature. Figure 7.1.10 shows the effect of polymer crystallinity and temperature on diffusion coefficients of 1-butanol and 1-octanol in poly(ethylene terephthalate). Increase of temperature facilitates diffusion (see also Figure 7.1.1). There is also difference in diffusion between two penetrants studied. Butanol has higher diffusion rate than octanol, which is easy to understand since butanol has smaller molecular volume (see also Figirre 7.1.3). Increase in crystallinity causes decrease of diffusion rate of both solvents. ... 

Impact resistance is either decreased or improved depending on the filler nature and its characteritics, namely particle size... 

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