Potential use of carbon nanotubes as a nanofiller for natural rubber latex condoms

The recent advancement in the field of nano-technology has raised much interest in the area of natural rubber latex (NRL) processing. This interest stems from the exceptional properties of nano-material and the promising results obtained by several researchers. Studies have shown that very low loadings of inorganic nanomaterials such as carbon nanotube (CNT) in NRL matrix leads to enhanced tensile strength, tensile modulus, tear resistance and aberration resistance. Thus providing a great prospect for reinforcement of thin film NRL articles such as condom. In this research, prevulcanised natural rubber latex (PvNRL) composite blends containing single walled carbon nanotubes (SWCNTs) were prepared via direct mixing. A progressive discolouration of PvNRL was observed with increased loadings of CNTs. Thermal analysis revealed faster drying rates for the composite blends containing SWCNT. Results from equilibrium swelling experiments also suggested a slight increase in crosslink density in the presence of SWCNT. There was a significant influence on flow behaviour of PvNRL as a result of varying loadings of SWCNT suspension. This was reflected as a change in pseudoplasticity and apparent viscosity. For Instance, apparent viscosity at a shear rate of 1 s-1 at 25°C for PvNRL with ~0.08% SWCNT was 2.5 Pa.s, compared to 0.49 Pa.s for the blends with 0.02% SWCNT. Condoms were moulded via the straight dipping technique using custom made glass formers. A series of dilutions was performed to correct the viscosity differences. This also ensured good consistency and promoted uniform deposition of PvNRL on the glass former. The average dimensions of the condoms produced in terms of length and width were ~191.17 ± 5.17 mm and 52.67 ± 5.17 mm respectively. Thickness measurement varied slightly according to the method of determination. The water leakage test suggested the absence of holes in the condoms produced. However, results from electrical leakage test contradicted those from water leak test. The results from infrared spectroscopy (FTIR) did not confirm the presence of chemical interactions between the SWCNT and PvNRL matrix. Glass transition temperature (Tg) was also unaffected across the blends. The stiffness (or modulus) was unaffected in all the condoms, as revealed by results from indentation hardness analysis. The SWCNT showed no significant influence on thermal decomposition temperatures of the condoms. Nonetheless, images from optical microscopy revealed increased surface roughness corresponding to higher loadings of SWCNT. Results from stress relaxation studies revealed improved retention of modulus under constant strain for condom samples containing SWCNT

Mechanical and Shape Memory Properties of 3D-Printed Cellulose Nanocrystal (CNC)-Reinforced Polylactic Acid Bionanocomposites for Potential 4D Applications

There is a growing need for diversified material feedstock for 3D printing technologies such as fused deposition modelling (FDM) techniques. This has resulted in an increased drive in the research and development of eco-friendly biopolymer-based composites with wide applications. At present, bionanocomposites of polylactic acid (PLA), biopolymer, and cellulose nanocrystals (CNCs) offer promising technical qualities suitable for FDM 3D printing applications due to their biodegradability and wide-ranging applications. In this work, the applicability of the PLA/CNCs bionanocomposites in 4D applications was investigated by studying its shape-recovery behaviour. Tensile and dynamic mechanical analysis (DMA) was used to elucidate the mechanical and flexural properties of the 3D-printed specimens. The results revealed improvement in the deflection temperature under load (DTUL), creep deformation, and recovery of the PLA/CNCs bionanocomposites. Tensile and static 3-point bending analyses of the bionanocomposites revealed improved tensile strength and modulus of the 3D printed parts. The potential 4D application of the PLA/CNCs bionanocomposites was also investigated by successfully printing PLA/CNC bionanocomposites directly onto a nylon fabric. The PLA/CNCs-fabric prototype included a foldable cube and grid-patterned designs. Additionally, the heat-induced shape memory behaviour of these prototypes was demonstrated

Mechanical and Shape Memory Properties of 3D-Printed Cellulose Nanocrystal (CNC)-Reinforced Polylactic Acid Bionanocomposites for Potential 4D Applications

There is a growing need for diversified material feedstock for 3D printing technologies such as fused deposition modelling (FDM) techniques. This has resulted in an increased drive in the research and development of eco-friendly biopolymer-based composites with wide applications. At present, bionanocomposites of polylactic acid (PLA), biopolymer, and cellulose nanocrystals (CNCs) offer promising technical qualities suitable for FDM 3D printing applications due to their biodegradability and wide-ranging applications. In this work, the applicability of the PLA/CNCs bionanocomposites in 4D applications was investigated by studying its shape-recovery behaviour. Tensile and dynamic mechanical analysis (DMA) was used to elucidate the mechanical and flexural properties of the 3D-printed specimens. The results revealed improvement in the deflection temperature under load (DTUL), creep deformation, and recovery of the PLA/CNCs bionanocomposites. Tensile and static 3-point bending analyses of the bionanocomposites revealed improved tensile strength and modulus of the 3D printed parts. The potential 4D application of the PLA/CNCs bionanocomposites was also investigated by successfully printing PLA/CNC bionanocomposites directly onto a nylon fabric. The PLA/CNCs-fabric prototype included a foldable cube and grid-patterned designs. Additionally, the heat-induced shape memory behaviour of these prototypes was demonstrated