Filling modification material

In recent years, there has been a breakthrough in the manufacturing cost of potassium titanate whiskers, aluminum borate whiskers, and so forth. Meanwhile, inexpensive and high-quality inorganic whiskers such as calcium carbonate, calcium sulfate, and magnesium are successfully synthesized, which makes inorganic whiskers a new type of filling modification material of polymer materials. This field has become a research hotspot all over the world and reveals broad application and market prospects. 

The results presented by Ling et al. [31], which are focused on carbon fibers as susceptors, describe a similar heating behavior like the one being observed with carbon black filled HDPE material. The work of John Harper [29] is related to the heating behavior of carbon black as a microwave susceptor in high density polyethylene by the modification of the surface area. The specific surface was varied from 7.5 to 137 m /g (Figure 2.14). 

Overall modification is the modification that occurs in both the interior and the surface of the polymer material. A feature of this kind of modification is that performance changes uniformly. Modification of polymer materials is mostly overall modification, such as filling modification, blending modification, crosslinking modification, morphology control modification, and so forth that were mentioned previously. 

Filling modification of polymer is the addition of solid additives with different composition and structure to the polymer matrix material to reduce costs or obviously change the performance of polymer products, which will improve the desired performance at the expense of other kinds of performance at the same time. Such an additive is known as a filler. Because these fillers are mostly inorganic powder, filling modification relates to performance difference and complementation of organic polymer and inorganic matter. This provides diverse areas of research and broad fields of application for filling modification. 

General Principles of Filling Modification of Polymer Materials... 

Therefore, in the practice of polymer filling modification, any extra effects of valuable performances of polymer materials must be prevented, and an integrated balance should be achieved among the contradictory effects. 

The properties of fillers such as geometric shape, particle size and distribution, physical and chemical properties, and so on will directly affect the material performances of the filling modification system. Fillers are classified mainly into the following kinds. 

In the blending process, whiskers may become damaged or even broken because of the impact and collision between whiskers and resin particles and the shear caused by the rotation of the screw. The constant length-to-diameter (Z/D) ratio of whiskers is the key for filling modification, so the speed of extrusion, the temperatures of different sections, and the position of the feed inlet of whiskers greatly influence the performance of the composite materials. Ge adds whiskers from the feed inlet of the twin-screw extruder and the first outlet respectively, and the performances of the composite material are shown in Table 4.2. 

Like other inorganic whiskers, calcium carbonate whiskers have high polarity, and therefore surface modification is required for filling polymer materials. The common surface... 

One of the important conclusions in this chapter is the high prospect of the modification method of epoxy composites in order to give them a set of specific properties using filled microencapsulated materials. 

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