J. Ismail

Carbon Black (CB)/Rice Husk Powder (RHP) Hybrid Filler-Filled Natural Rubber Composites: Effect of CB/RHP Ratio on Property of the Composites

Carbon black (CB)/rice husk powder (RHP) hybrid filler filled natural rubber (NR) composites with various filler ratios (0/30, 5/25, 10/20, 20/10 and 30/0) were prepared. The influence of CB/RHP ratio on curing characteristics, tensile properties and fatique life of the composites was investigated. It has been found that incorporation of CB in the hybrid filler decreases the scorch time and cure time but increases maximum torque. As CB content increases, the tensile strength, modulus at 100% and 300% elongation and fatique life increase whereas the elongation at break decreases. SEM studies also reveal poor adhesion between RHP particles and NR matrix which causes inferior mechanical properties.

The Effect of Rice Husk Powder on Standard Malaysian Natural Rubber Grade L (SMR L) and Epoxidized Natural Rubber (ENR 50) Composites

The effects of rice husk powder (RHP) loading and two types of natural rubber matrix (SMR L and ENR 50) on curing characteristics and mechanical properties were studied. The scorch time and cure time decreased with increasing RHP loading whereas maximum torque showed an increasing trend. SMR L composites possessed longer scorch time and cure time than ENR 50 composites. Incorporation of RHP into both rubbers improved tensile modulus significantly but decreased tensile strength and elongation at break. SMR L composites exhibited the lower tensile modulus and higher tensile strength and elongation at break than ENR 50 composites.

Electrical and thermal behavior of copper-epoxy nanocomposites prepared via aqueous to organic phase transfer technique

The preparation, electrical, and thermal behaviors of copper-epoxy nanocomposites are described. Cetyltrimethylammonium bromide - (CTAB-) stabilized copper (Cu) particles were synthesized via phase transfer technique. Isopropanol (IPA), sodium borohydride (NaBH4), and toluene solution of diglycidyl ether of bisphenol A (DGEBA) were used as transferring, reducing agent, and the organic phase, respectively. The UV-Vis absorbance spectra of all the sols prepared indicate that the presence of Cu particles with the particles transfer efficiency is ≥97%. The amount, size, and size distribution of particles in the organosol were dependent on the content of organic solute in the organosol. The composites were obtained upon drying the organosols and these were then subjected to further studies on the curing, thermal, and electrical characteristic. The presence of Cu fillers does not significantly affect the completeness of the composite curing process and only slightly reduce the thermal stability of the composites that is >300°C. The highest conductivity value of the composites obtained is 3.06 × 10-2 S cm-1.

Solvent effect on the morphology of copper (I) oxide: A fundamental study towards copper (I) oxide-epoxy composites

The study on the influence of solvent environments on the Cu2O particles preparation via aqueous to organic phase transfer technique is described. In aqueous, the morphologies of the as-formed particles are of whisker-like or ellipsoidal shape dependent on the amount of CTAB used. At lower concentration of CTAB (r=2.7), Cu2O particles tend to form bundle of fine needle-like structures with an average diameter of 14.1±4.3 nm. Upon phase transfer process, transformation of Cu2O morphology occurred. Two organic solvents namely chloroform and toluene is studied. Chloroform with higher dielectric constant and dipole moment exert better particle-solvent interaction thus give better particle dispersion as compared to toluene. Addition of 10% v/v epoxy in the organic solvent further affects the particles morphology. Spherical particles as small as 8.1 ± 2.1 nm are obtained for Cu2O particles transferred into the 10%v/v epoxy/chloroform. Better solvation of epoxy resin in chloroform makes it a better stabilizer thus protecting the particles from agglomeration and secondary growth.

Nano silica dispersion in epoxy : the investigation of heat, milling speed and duration effect

Nano composites are a promising development but the challenge of homogenous and discrete dispersion of the nano fillers are barriers that must be overcome before they can be effectively implemented. Although the common dispersion methods such as particle surface modification, comprehensive milling metrologies and the usage of solvents bear results, these are time consuming and not cost effective. In this paper, we explore the efficiency of coupling the usage of ball-media and heat on the dispersion of nano silica in epoxy. No solvents are involved. The effects of milling speed and duration are also studied albeit under a fixed ball media : silica-epoxy volume ratio of 3:5. The experiment set-up involves a simple 3-blade mixer, round bottom flask and 60 ? m zirconia ball. At nano silica loading of 10 wt % the nano silica clusters are systematically reduced from 1.5 - 2 ? m to 100 - 200 nm with the usage of ball media and application of heat. At the optimum milling speed and duration of 500 rpm for 5 hours, the aggregate sizes were further reduced to 30 - 70 nm, which is almost a discrete dispersion.