Filling modification characteristics

With the development of filling modification technology and a deepening understanding of fillers, reasons for using them, especially the functional fillers, have expanded from pure cost reduction to a provision of some performance characteristics to products, such as electrical property, magnetism, electric wave absorbency, ultraviolet resistance, antibiosis, and other special... 

The use of irradiated PTFE powder in EPDM gives enhanced mechanical properties as compared to composites containing nonirradiated PTFE. The existence of compatibility between modified PTFE powder and EPDM is indirectly revealed by , DSC, and SEM. shows that modified PTFE powder (500 kGy-irradiated) is obviously but partially enwrapped by EPDM as compared to nonirradiated PTFE powder. This leads to a characteristic compatible interphase around the modified PTFE. The resultant chemically coupled PTFE-filled EPDM demonstrates exceptionally enhanced mechanical properties. Crystallization studies by DSC also reveal the existence of a compatible interphase in the modified-PTFE-coupled EPDM. The synergistic effect of enhanced compatibility by chemical coupling and microdispersion of PTFE agglomerates results in improvement of mechanical properties of PTFE-coupled EPDM compounds. In summary, an effective procedure both for the modification of PTFE powder as well as for the crosslinking of PTFE-filled EPDM by electron treatment has been developed for the preparation of PTFE-coupled EPDM compounds with desired properties. 

The characteristics of pore structure in polymers is a key parameter in the study of diffusion in polymers. Pore sizes ranging from 0.1 to 1.0 pm (macroporous) are much larger than the pore sizes of diffusing solute molecules, and thus the diffusant molecules do not face a significant hurdle to diffuse through polymers comprising the solvent-filled pores. Thus, a minor modification of the values determined by the hydrodynamic theory or its empirical equations can be made to take into account the fraction of void volume in polymers (i.e., porosity, e), the crookedness of pores (i.e., tortuosity, x), and the affinity of solutes to polymers (i.e., partition coefficient, K). The effective diffusion coefficient, De, in the solvent-filled polymer pores is expressed by ... 

Locality Depth of faulting (m) Matrix cement prior to faulting Fault throws (m) Deformation characteristics Fault cement Later, burial modification of faults Max. burial (m) Late uplift Late extensional fracture fill... 

The use of the complex with A -substituted-phenylstyrylacrylohydroxamic acid and Aliquat 336 for the determination of V in alloys, rock, environmental and clinical samples has recently been reported [1]. Studies on the complexation of V(V) with PAR on the solid phase of a fibrous sorbent filled with an anion exchanger were described [2]. The DL of of 3-4 ng ml V was achieved. The effect of modification of a solid support with 8-hydroxyquinoline and 8-hydroxyquinoline-5-sulfonic acid on analytical characteristics of the reaction of vanadium(V) with PAR on a solid phase was studied [3]. Extraction of V with the use of 3-hydroxy-2-(4-methoxyphenyl)-6-methyl-4//-chromen-4-one was employed to detect V in flue dust and steel [4]. 

Whilst many of these areas fall outside the scope of this chapter, particulate polymer composites are becoming increasingly complex and commonly require more than just inclusion of a filler or particle additive in order to achieve optimum properties. For example, rubber modification of mineral-filled thermoplastics to yield a balance of enhanced toughness and stiffness, is an area of commercial importance. In these ternary-phase systems, there is not only a requirement to attain good dispersion of the filler component, but also a need for breakdown of the rubbery inclusion to yield the most effective size and spatial location within the composition. Whilst this may depend to a large extent on characteristics of the material s formulation, it can also be influenced by the material s compounding route. 

In the indirect method, surface-modified whiskers are filled into polymers to prepare composite materials and the surface modification effects of whiskers can be evaluated by studying characteristics of composites, such as mechanical, thermal, and electrical properties. This method is the most often used. 

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