Mechanical properties and dynamic mechanical analysis of thermoplastic-natural-rubber-reinforced short carbon fiber and kenaf fiber hybrid composites

The hybridization of thermoplastic natural rubber based on carbon fiber (CF) and kenaf fiber (KF) was investigated for its mechanical and thermal properties. Hybrid composites were fabricated with a melt-blending method in an internal mixer. Samples with overall fiber contents of 5, 10, 15, and 20 vol % were subjected to flexural testing, and samples with up to 30% fiber content were subjected to impact testing. For flexural testing, generally, the strength and modulus increased up to 15 vol % and then declined. However, for impact testing, higher fiber contents resulted in an increment in strength in both treated and untreated composites. Thermal analysis was carried out by means of dynamic mechanical analysis on composites with 15 vol % fiber content with fractions of CF to KF of 100/0, 70/30, 50/50, 30/70, and 0/100. Generally, the storage modulus, loss modulus, and tan d for the untreated hybrid composite were more consistent and better than those of the treated hybrid composites. The glasstransition temperature of the treated hybrid composite was slightly lower than that of the untreated composite, which indicated poor damping properties. A scanning electron micrograph of the fracture surface of the treated hybrid composite gave insight into the damping characteristics

Effects of liquid natural rubber (LNR) on the mechanical properties of LNR toughened epoxy composite

The effects of liquid natural rubber (LNR) on the morphology and mechanical properties of rubber modified epoxy were investigated. Epoxy composites were prepared in four different compositions of LNR (3, 5, 7 and 9phr) by using twin screw extruder. The samples for tensile, fracture toughness and impact tests were prepared according to ASTM D 638, D 5045 and D 256. The elastomeric nature of rubber can act as energy dissipating centre to cause the ductile fracture for the rubber modified epoxy. They was an obvious increment of fracture toughness where maximum value was observed with 3 phr LNR. A clear increment of impact strength at 3 phr LNR was observed, followed by a small increment at 5 phr and no further increment at 7 and 9 phr LNR. The tensile strength showed a similar trend with impact strength and Young’s modulus. SEM micrographs showed an increment of rubber particle size when the amount of LNR was increased and caused the mechanical properties to drop

Mechanical properties of thermoplastic natural rubber (TPNR) reinforced with different types of carbon nanotube

The effect of various multi-walled carbon nanotubes (MWNTs) on the tensile properties of thermoplastic natural rubber (TPNR) nanocomposite was investigated. The nanocomposite was prepared using melt blending method. MWNTs were added to improve the mechanical properties of MWNTs/TPNR composites in different compositions of 1, 3, 5, and 7 wt.%. The results showed that the mechanical properties of nanocomposites were affected significantly by the composition and the properties of MWNTs. SEM micrographs confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which was improved mechanical properties significantl

Thermal behavior of MWNT-reinforced thermoplastic natural rubber nanocomposites

This article studies the thermal properties of a multi-walled carbon nanotube (MWNT)-reinforced thermoplastic natural rubber (TPNR) nanocomposite. The nanocomposite was prepared using a melt blending method. Various percentages (1, 3, 5, and 7 wt%) of MWNTs were added into TPNR to improve its thermal properties. The laser flash technique was also employed to determine the thermal conductivity, thermal diffusivity, and specific heat capacity of the nanocomposite. The DMA result showed that the glass transition temperature (Tg) increased with the increase in MWNT content. TEM micrographs also demonstrated that a good dispersion of MWNTs was achieved in the TPNR environment