Preparation and characterisation of crosslinked polycaprolactone and natural rubber (SMR CV60) blends

Polycaprolactone (PCL) and natural rubber (NR) blends were prepared using a melt blending process, in the absence and presence of an organic peroxide crosslinking agent. The resulting blends were then characterised for their functional groups using Fourier transform infrared analysis (FTIR), surface morphology using scanning electron microscopy (SEM), crosslink degree using gel content measurements, physical properties using tensile measurements and viscoelastic properties using dynamic mechanical analysis (DMA). FTIR analysis revealed the reduction in C=O stretching and C–O bending of PCL due to crosslinking whereas SEM analysis showed rougher and more irregular surfaces with holes and grooves as well as increasing PCL concentration. Similarly, surfaces with holes after extraction with acetone were also observed using SEM. Gel content experiments showed an increase in gel content of the blends with crosslinking, which reduced with increasing PCL concentration. On the other hand, tensile strength and modulus at 300% increased after crosslinking and PCL concentration. However, the elongation at break after crosslinking showed an opposite increasing effect. DMA showed that crosslinking resulted in a more elastic blend behaviour with an increase in the glass transition temperature, Tg for all blend ratios

Preparation and Characterisation of Crosslinked Natural Rubber (SMR CV 60) and Epoxidised Natural Rubber (ENR-50) Blends

In this sudy, the influenceof di(tert-butylperoxyisopropyl)benzene (DTBPIB) on the properties of natural rubber (NR) blend with epoxidized natural rubber (ENR) was determined. Fourier transform infrared spectroscopy with attenuated total refletance analysis and gel content confired crosslinking occurred in the rubber blends in the presence of peroxide DTBPIB percentage. Studies including tensile properties, dynamic mechanical properties, thermogravimetric analysis (TGA) and water absorptivity showed the changes in properties of the crosslinked NR/ENR blends. Tensile properties analysis disclosed the improvements in the modulus at 300% elongation and tensile stength with increasing NR ratios. Dynamic mechanical analysis revealed the blends to be incompatible and immiscible, with ENR showing a more viscous behaviour compared to the polymer blends. Thermal properties improved by blending NR with ENR as the onset temperature of NR/ENR: 50/50 was higher than pure NR by approximately 10oC and ENR by approximately 2oC. Water absorptivity experiment revealed a two-fold reduction in the presence of crosslinking for all blend ratios