Dynamic mechanical analysis of binary and ternary polymer blends based on nylon copolymer/EPDM rubber and EPM grafted maleic anhydride compatibilizer

The dynamic mechanical properties such as storage modulus, loss modulus and damping properties of blends of nylon copolymer (PA6,66) with ethylene propylene diene (EPDM) rubber was investigated with special reference to the effect of blend ratio and compatibilisation over a temperature range –100°C to 150°C at different frequencies. The effect of change in the composition of the polymer blends on tanδ was studied to understand the extent of polymer miscibility and damping characteristics. The loss tangent curve of the blends exhibited two transition peaks, corresponding to the glass transition temperature (Tg) of individual components indicating incompatibility of the blend systems. The morphology of the blends has been examined by using scanning electron microscopy. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends. Finally, attempts have been made to compare the experimental data with theoretical models.

Compatibility Studies on Sulphur Cured EPDM/CIIR Blends

The principal objective of this study was to explore the compatibility of a blend of two synthetic elastomers viz., ethylene-propylene-diene rubber (EPDM) and chlorobutyl rubber (CIIR). Various commercial grades of EPDM were blended with a specific grade of CIIR at different proportions. The mechanical properties such as tensile strength, tear strength, ageing resistance, etc. were studied. On the basis of the observed physical properties, two particular grades of EPDM were found to be compatible with CIIR. Differential scanning calorimetry and scanning electron microscopy confirmed the results. Chlorosulphonated polyethylene was added as a compatibilizing agent to overcome the phase separation of the other two incompatible grades of EPDM in blending with CIIR. The results revealed that the addition of compatibilizer greatly improves the compatibility and thereby the properties of the blends.

Synthesis and Characterisation of Thermoplastic Ionomers based on Natural Rubber

Chemically modified novel thermo-reversible zinc sulphonated ionomers based on natural rubber (NR), radiation induced styrene grafted natural rubber (RI-SGNR), and chemically induced styrene grafted natural rubber (CI-SGNR) were synthesized using acetyl sulphate/zinc acetate reagent system. Evidence for the attachment of sulphonate groups has been furnished by FTIR spectra. which was supplanted by FTNMR results. Estimation of the zinc sulphonate group was done using spectroscopic techniques such as XRFS and ICPAES. The TGA results prove improvement in the therrno-oxidative stability of the modified natural rubber. Both DSC and DMTA studies show that the incorporation of the ionic groups affect the thermal transition of the base polymer. Retention of the improved physical properties of the novel ionomers even after three repeated cycles of mastication and molding at 120 degree C may be considered as the evidence for the reprocessabiJity of the ionomer. Effect of both particulate (carbon black. silica & zinc stearate) and fibrous fillers (nylon & glass) on the properties of the radiation induced styrene grafted natural rubber ionomer has been evaluated. Incorporation of HAF carbon black results in maximum improvement in physical properties. Silica reinforces the backbone chain and weakens the ionic associations. Zinc stearate plays the dual role of reinforcement and ptasticization. The nylon and glass filled lonorner compounds show good improvement in the physical properties in comparison with the neat ionomer. Dispersion and adhesion of the fillers in the ionomer matrix has been amply supported by their SEM micrographs. Microwave probing of the electrical behavior of the 26.5 ZnSRISGNR ionomer reveals that the maximum relative complex conductivity and the complex permittivity appear at the frequency of 2.6 GHz. The complex conductivity of the base polymer increases from 1.8x 10.12 S/cm to 3.3xlO·4 S/cm. Influence of fillers on the dielectric constant and conductivity of the new ionic thermoplastic elastomer has been studied. The ionomer I nylon compound shows the highest microwave conductivity. Use of the 26.5 ZnS-RISGNR ionomer as a compatibilizer for obtaining the technologically compatible blends from the immiscible SBR/NBR system has been verified. The heat fugitive ionic cross-linked natural rubber may be, therefore, useful as an alternative to vulcanized rubber and thermoplastic elastomer

Rice husk ash – A valuable reinforcement for high density polyethylene

This paper presents the results of a study on the use of rice husk ash (RHA) for property modification of high density polyethylene (HDPE). Rice husk is a waste product of the rice processing industry. It is used widely as a fuel which results in large quantities of RHA. Here, the characterization of RHA has been done with the help of X-ray diffraction (XRD), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICPAES), light scattering based particle size analysis, Fourier transform infrared spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Most reports suggest that RHA when blended directly with polymers without polar groups does not improve the properties of the polymer substantially. In this study RHA is blended with HDPE in the presence of a compatibilizer. The compatibilized HDPE-RHA blend has a tensile strength about 18% higher than that of virgin HDPE. The elongation-at-break is also higher for the compatibilized blend. TGA studies reveal that uncompatibilized as well as compatibilized HDPERHA composites have excellent thermal stability. The results prove that RHA is a valuable reinforcing material for HDPE and the environmental pollution arising from RHA can be eliminated in a profitable way by this technique.

HDPE-Ash Nanocomposites

Ash-based polymer composites are assuming increasing importance because of the pollutant potential, fine particle size, and low price of ash. Fly ash and rice husk ash are two prominent ash materials on which some investigations have already been done for potential use in polymer composites. This article highlights the results of a study on the use of wood ash in HDPE. Wood ash is mainly a mixture of various metallic compounds and some silica. Here, the characterization of wood ash has been done with the help of XRD, ICPAES, light scattering based particle size analysis, FTIR, and SEM. The results show that wood ash particle size has an average value of 293 nm, much lower than other categories of ash. When blended with HDPE in the presence of a compatibilizer, wood ash gives rise to vastly improved mechanical properties over that of the base polymer. The results prove that wood ash is a valuable reinforcing material for HDPE and the environmental pollution due to wood ash can be solved in a most profitable way by this technique.