Particle filled composite

Minerals and other particles are used as fillers in plastic moldings either to enhance mechanical properties or to reduce shrinkage and flammability. The minerals and other particles used as commercial fillers are mica, clay, talc, silica, woUastonite, glass beads, carbon black and calcium carbonate. Theberge [331] summarized 

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G-10CR and G-l ICR was about 20-25 times greater than that of the particle-filled composites such as Stycast 2850 FT and EPON 828. 

Fracture mechanisms in most inorganic particle filled composites can be described by the crack-front bowing theory 1,18,19), Originally proposed by Lange in 1970 (75), it describes the relationship between a mobile crack front... 

Ada Adachi, T., Osaki, M., Araki, W., Kwon, S. C. Fracture toughness of nano- and micro-spherical silica-particle-filled composites. Acta Mater. 56 (2008) 2101-2109. 

Properties of particle-filled composites, such as strength, toughness, and impact resistance, depend on the material properties of both matrix and filler. Of importance are the size and shape of the filler particles and interactions between them, the total volume occupied by the filler, the presence of voids in the structure, and the degree of adhesion between filler and matrix. When the elastic modulus of the filler is higher than that of the matrix, the modulus of the composite usually increases in proportion to the volume fraction of filler. Opposite behavior is expected if the matrix is more rigid than the filler. 

Some investigations [105-107] on micron-.size particle-filled composites demonstrated that fracture toughness is dramatically influenced by the particle shape, size, volimie fraction, and particle/matrix interfacial strength. Brunner et al. [108] reviewed the development of fracture mechanics test methods in determination of fracture toughness and delamination resistance of fiber-reinforced polymer composites. 

Although the expressions for and its relation to are originally derived for homogeneous, isotropic materials, it has been successfully utilized for particle-filled composites as follows ... 

Figure 1.13 Particle-filled composite with a broad size distribution of spherical glass beads ...

Compounding of long fiber reinforced thermoplastics (LFRTs) is very different from compounding short fiber or particle filled composites. Long fibers enhance properties such as impact strength and are finding great utility in a number of applications in the automotive, industrial, and sports markets. Most of these products use PP or polyamide (PA), but poly(ethylene tere-phthalate) (PET) and other resins are also used. 

Nanocomposites are a new class of particle-filled composites in which at least one dimension of the dispersed particles is within 100 nm. Because of the dispersion of nanosize clay particles, polymer-clay nanocomposites exhibit improved moduli and strength, decreased thermal expansion coefficient, decreased gas permeability, increased swelling resistance, better thermal stability and enhanced ionic conductivity when compared to the pristine polymers or microscale composites [149-151], They find increased applications in various fields such as automobile, packaging, electronic, coating and aerospace industries [152,153],... 

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