Effect of Fiber Loading

Rice husk NR Mechanical properties Resulted in improved hardness but decreased tensile strength and tear strength. Better resilience property than that of silica and carbon black. [11] 

Coir NR Stress relaxation behavior Rate of relaxation was high for the NR compound, and decreased when fiber loading increased from 30 to 60phr. 17] 

Oil palm—wood flour-NR Tensile properties tear strength elongation at break hardness Increasing OPWF loading in NR resulted in the reduction of tensile strength, tear strength, and elongation at break while there was an increase in the tensile modulus and hardness. 20  

Sisal fiber-NR Mechanical properties Tensile strength decreased up to 17.5 vol% loading and then increased. The tear strength and modulus values showed a consistent increase. [21  

---

For tests other than E-84, there have been some studies on the effects of fiber loading and fiber layup on composite flammability. This has primarily been work done by the U.S. Navy on the flammability of composites used in naval vessel flammability,19-20 or work by Kandola et al.10-21-22 on the effect of fiber type and content on polymer composites studied by cone calorimeter. More work is being conducted in studying the effects of fiber orientation and lay-up not on overall flammability performance, but flammability performance under structural load. This is the most important for aircraft, vehicles, and buildings where the composites are structural members. The concern here is... 

Figure 9.8 Effect of fiber loading on the steady state viscosity ( ) virgin PP, (A) 10% PP/sisal, (x) 15% PP/sisal, (o) 30% PP/sisal [74].

Table 9.4 Effect of fiber loading and MAPE concentration on K and n values [74].

In a natural fiber polymer composite, natural fiber is incorporated in a definite volume in the polymer matrix. Mechanical properties can be enhanced by increasing the fiber volume in a composite, but after a certain level, it may start decreasing due to the poor bonding between fiber and matrix. Oksman et al. [9] studied the effect of fiber loading with epoxy polymer. As shown in the Table 22.5, sisal fiber... 

Table 22.5 Effect of fiber loading on tensile properties of sisal fibCT reinforced epoxy thermoset composite...

Table 22.6 Effect of fiber loading on impact properties of sisal fiber reinforced polyester composite...

Annie Paul S, Boudenne A, Ibos L et al (2008) Effect of fiber loading and chemical treatments on thermophysical properties of banana fiber/polypropylene commingled composite materials. Compos A 39 1582-1588... 

Effect of fiber loading The water absorption by OPF-PU composites increased sharply on the day of immersion and remained constant during the following 5 days [65]. Composites with 75% fiber content absorbed 55% water and composites with 65% fiber absorbed 48% water after 1 day of immersion. Weak bonding between the matrix... 

Effect of fiber loading The loss in tensile properties of OPF-polyester composites upon degradation in soil was quantified by. Loss in tensile strength by 8%, 17% and 35% were observed, respectively after exposure of 3,6 and 12 months. Similarly tensile modulus, elongation at break and impact strength also reduced upon soil exposure. A loss of impact strength by 6%, 18% and 43% were observed, respectively after 3, 6 and 12 months. Similarly the tensile stress, tensile modulus and elongation at break decreased from 35.1 MPa, 3.29 GPa and 3.75%, 34.6 MPa, 2.32 MPa and 2.48%, respectively upon soil burial for 12 months [61]. 

Effect of fiber loading Oil palm fiber-PF composites exhibited lowest sorption at a fiber content of 40% among various fiber contents in the range of 10% to 50% [23]. It is interesting to note that maximum mechanical properties were also exhibited at this fiber content. The OPF- glass fiber-PF hybrid composites were found more hydrophilic than unhybridized composites due to the poor compatability between the OPF and glass fiber. It was also observed that the water absorption of OPF-PF composites are diffusion controlled and follow fickian behavior, whereas hybridization with glass fibers caused a deviation from fickian behavior. 

Effect of fiber loading The thermal conductivity and thermal diffusivity of OPF-reinforced PF composites was less than that of pure resin. The thermal conductivity ( ) and thermal diffusivity (x) of xmtreated OPF-PF composite of 40% fiber loading was 0.29 W/mK and 0.16 mmVs, respectively where as the thermal conductivity and thermal diffusivity of pure PF were 0.348 W/m K and 0.167 mmVs, respectively [74]. The effective thermal conductivity of composite can also be predicted from individual thermal conductivities of fibers and matrix by employing different models [75]. The incorporation of OPF in PF matrix resulted in decrease of glass transition temperature [20]. This was due to higher void formation at higher fiber content as voids facilitate the chain mobility at lower temperatures resulting decrease in T value. 

Effect of fiber loading From the studies on the dielectric constant of OPF-LLDPE composites, the dielectric constant is found to increase with fiber loading [39]. This trend of increase in effective dipole moment of the composites was due to the polar groups in the filler material [78]. Similar trend for coconut fiber-polypropylene composites were also observed [79]. It is interesting to note that the increase in dielectric constant with OPF loading was more prominent in case of alkali-treated fiber composites. 

A.S. Singha, and R.K. Rana, Natural fiber reinforced polystyrene composites Effect of fiber loading, fiber dimensions and surface modification on mechanical properties. Mater. Des. 41,289-297 (2012). 

Mechanical properties were evaluated for cellulose-polypropylene composites. Figure 1 shows the effect of fiber loading on the tensile strength with and without the addition of Coupling Agent C. 

Singha AS, Thakur VK (2008b) Effect of fiber loading on urea formaldehyde matrix based green composites. Iran Polym J 17(ll) 861-873... 

EFFECT OF FIBER LOADING ON STRENGTH AND MODULUS OF FP/Pb COMPOSITES... 

Ramanaiah, K., Ratna Prasad, A.V., and Hema Chandra Reddy, K. (2012) Effect of fiber loading on mechanical properties of Borassus seed shoot fiber reinforced polyester composites. J. Mater. Environ. Sci., 3 (3), 374-378. 

---