Lubricants are very important consumables in all industries as failure in machine parts due to absence or wrong choice of lubricants carries enormous cost. The base oil used for the formulation of most lubricants is environmentally hostile mineral oil and 30% of lubricants consumed ends up in the ecosystem. However, mineral oil reserve is depleting and the environmental concern about the damaging impact of mineral oil is growing. The search for environment friendly substitutes to mineral oils as base oils in lubricants has become a frontier area of research in the lubricant industry. Vegetable oils are perceived to be alternatives to mineral oils for lubricant base oils due to certain inherent technical properties and their ability to be biodegradable. This paper is an overview of recent research on vegetable oils as base oil for lubricant production with focus on the prospects, challenges and efforts to overcome the challenges of using vegetable oils as base oil for the production of industrial lubricants. Compared to mineral oils, vegetable oils in general possess high flash point, high viscosity index, high lubricity, low evaporative loss, are renewable, and are environmentally friendly. Poor oxidative and hydrolytic stability, high cost, food versus energy debate, high temperature sensitivity of tribological behaviour and poor cold flow properties are reckoned to be the limitations of vegetable oils for their use as base oils for industrial lubricants. The current effort to overcome these limitations includes the use of non edible oils, additives, chemical modifications and thermal modifications. More research and legislation in favour of the use of vegetable oil lubricants is recommended.

Inhibitors are added to concrete to improve its quality and integrity. In recent years the use of these inhibitors in producing high performance concrete has increased significantly as a result of aggressive environment. This report is based on the corrosion inhibitors used in concrete and also on the published literatures. Most authors agreed that reinforcement corrosion is the most important causes of premature failure of reinforced concrete structure worldwide and generate a great research concern due to its effects on global economy. The report presents information related to basic mechanism of corrosion protection methods to extend the service life of reinforced concrete structures which include inhibitors, sealers and barriers. Environmental sustainability issues concerning the present inhibitors being used were examined, viability and versatility of green inhibitors to concrete was also x-rayed.

This research is motivated by the desire to restore the quality of life to amputees. The study uses multi-walled carbon nanotube (WMCNT) reinforced natural rubber (NR) polymer nanocomposite (PNC) for prosthetic foot application. The compound formulation was carried out in accordance to a modified procedure described by Hemkaew et al. Mixing of the ingredients during vulcanisation was performed according to ASTM D-3182 standard on an open two-roll mill. The various compositions of the nanocomposites (NCs) were cured at a temperature of 150 ± 2 °C and a pressure of 0.2 MPa for 10 minutes in an electrically heated hydraulic press. Mechanical investigation revealed that NR/MWCNT-3 exhibited the highest capacity to withstand tensile and dynamic loading (449.79 MPa). It also showed superior filler distribution and hence improved crystallinity and cross-link. Water absorption test indicated that NR/MWCNT-3 offers optimum dimensional stability at ambient conditions. Moreover, thermogravimetric analysis/differential thermogravimetry (TGA/DTG) showed degradation peaks at 305 °C and 290 °C respectively with temperature range within which the NCs degraded lying between 250 °C and 600 °C. Dynamic mechanical analysis (DMA) revealed that filler incorporation results in higher storage and loss moduli (2000–7500 MPa and 500–1413 MPa respectively). Tan δ curves proved that NR/MWCNT-3 has the highest capacity to dissipate energy through segmental motion. Furthermore, microstructure examination confirmed good filler/matrix adhesion as NR/MWCNT-3 indicated improved interaction; hence higher strength (6.02 MPa) of the NC. Better wear resistance ability can also be reported of the newly developed than existing prosthetic material. It can be deduced that the formulated nanocomposite from MWCNTs for reinforced natural rubber is suitable for the development of the anthropomorphic prosthetic foot.

The dynamic mechanical analysis (DMA) of crosslinked natural rubber nanocomposites reinforced with cellulosic nanoparticles obtained from lignocelluloses biomass (coconut husk, bamboo culm and cotton linters) has been investigated and compared with carbon black filled natural rubber vulcanizate. The crosslinked natural rubber matrix based composites were produced by melt intercalation process using two roll mixing mill and vulcanized in a thermally regulated hydraulic press. DMA were carried out in order to obtain their viscoelastic thermo-mechanical spectrum. Results showed decrease in storage modulus (E') with increasing temperature while glass transition temperatures (Tg) obtained from temperature dependence loss tangent curves were -35.84, 37.30, -34.61, -35.27 and -34.29 o C for neat-natural rubber (NR), natural rubber reinforced carbon black (NR-CB), natural rubber reinforced bamboo cellulosic particles (NR-BNC), natural rubber reinforced coconut husk cellulosic particles (NR-CHNC) and natural rubber reinforced cotton linter particles (NR-CLNC) respectively. The composite of NR-CHNC was also found to give a higher damping factor of 1.563 compared to NR-CB which gave a value of 1.518. nanocomposites reinforced with cellulosic nanoparticles can provide adequate synergy for loading bearing and vibration isolation application.

This research focuses on the use of cellulosic nanoparticles obtained from coconut husk, bamboo and cotton linter as reinforcing phase in natural rubber composites with the objective to study the effect of these cellulosic particles and loading ratio on the mechanical, thermal and morphological properties of the resultant composites. Vulcanized natural rubber composites were prepared using cellulosic nanoparticles obtained from bamboo (BNC), coconut husk (CHNC), cotton linter (CLNC) and carbon black (CB) as reinforcing material/fillers. These reinforcing material/fillers were compounded alongside with vulcanizing agents using two roll mixing mill and subsequently cured in order to introduce crosslinks into rubber chains. Scanning electron microscope (SEM) revealed that the free volume holes in the neat rubber were drastically reduced by incorporation of these nanoparticles into the rubber matrix. The differential scanning calorimetric (DSC) study showed a slight shift in the melting temperature of bamboo based composite from 360 to 350 o C while thermo gravimetric analysis (TGA) showed that the incorporation of bamboo and cotton linter based nanoparticles shifted the thermal stability of neat rubber matrix from 266 to 299 and 300 o C respectively. Coconut husk based composites showed a trend of increase in tensile strength from 1.8 to 3.82 MPa with filler loading of 0 to 25 weight %, while bamboo, cotton linter and carbon black based nanocomposites gave their highest values of 3.16, 3.92 and 4.50 MPa respectively at filler content of 30 weight %.Cellulosic nanoparticles obtained from biomass studied in this experiment can replace or serve as alternative materials to carbon black especially in moderate load bearing rubber articles