Baharin Azahari

The Effect of Bis(3-Triethoxysilylpropyl) Tetrasulfide on Silica Reinforcement of Styrene-Butadiene Rubber

Abstract Bis(3-triethoxysilylpropyl)tetrasulfide (TESPT) was found to affect the curing characteristics and the physical properties of styrene-butadiene (SBR) gum rubber and xin situ silica-filled SBR vulcanizates. Silica incorporated by the in situ sol-gel reaction of tetraethoxysilane with TESPT showed a much higher reinforcing efficiency than did conventional mechanical mixing and the in situ method without TESPT. The higher reinforcing efficiency is attributed to the formation of a silica-rubber network, which also changed the dynamic mechanical behavior of the SBR vulcanizates. Transmission electron microscopy observations showed in situ silica incorporation of very fine particles in comparison to the sol-gel process without TESPT.

Physico-chemical characteristics and sensory evaluation of wheat bread partially substituted with banana (Musa acuminata X balbisiana cv. Awak) pseudo-stem flour

The physico-chemical and sensorial properties of the control (BCtr), commercial wheat flour (CWF) bread substituted with 10% BPF (banana pseudo-stem flour) (B10BPF) and B10BPF with added 0.8% w/w (flour weight basis) xanthan gum (XG) or sodium carboxymethylcellulose (CMC) (B10BPFXG and B10BPFCMC, respectively) were examined. The proximate analyses revealed that the composite bread had significantly higher moisture, ash, crude fibre, soluble, insoluble and total dietary fibre contents but lower protein, fat and carbohydrate contents than the BCtr. Bread incorporated with BPF resulted in a lower volume, darker crumb and lighter crust colour than the BCtr. The addition of CMC improved the bread volume. All breads containing BPF had greater total phenolics, and antioxidant properties than the control bread. Sensory evaluation indicated that the B10BPFCMC bread had the highest acceptability.

Adsorption Studies of Methylene Blue and Malachite Green From Aqueous Solutions by Pretreated Lignocellulosic Materials

Lignocellullosic materials have been used as low-cost adsorbents for the removal of methylene blue (MB) and malachite green (MG) dyes from aqueous solutions. The organic compounds in the adsorbents that contribute to chemical oxygen demand (COD) have been removed through pretreatment of the adsorbents. The percentage of color removal and COD reduction of both MB and MG dyes were found relatively close in values. The adsorption process followed the Langmuir isotherm as well as the Freundlich isotherm and pseudo-second order kinetic model. The process was found to be endothermic in nature.

An investigation of the potential of rice husk ash as a filler for epoxidized natural rubber—II. Fatigue behaviour

Abstract The fatigue behaviour of white rice husk ash (WRHA) filled ENR-50 vulcanisate was compared with those of silica and carbon black filled ENR-50. The effects of the silane coupling agent (δ-mercaptopropyltrimethoxysilane, vulcanisation systems, hysteresis and the failure mode of the vulcanisates were studied. It was found that the incorporation of fillers reduced the fatigue life of vulcanisates, while silica filled ENR vulcanisates showed the best fatigue life followed by WRHA, then carbon black filled vulcanisates. The coupling agent improved fatigue life with a simultaneous reduction in WRHA filler aggregates and improved filler dispersion for all vulcanisates. Conventional vulcanisation systems gave the highest fatigue life followed by semi-efficient and then efficeint vulcanisation systems. Carbon black filled ENR vulcanisates showed the highest hysteresis as indicated by the strain exponent. The failure mode was found to be of a dual nature.

Synthesis and Characterization of Nano-Silver Incorporated Natural Rubber Latex Foam

Synthesis and characterization of silver nanoparticles (SNP) incorporated natural rubber latex foam (NRLF) is described. SNP synthesized by reducing of Silver Nitrate (AgNO3) with Tri-Sodium Citrate (TSC) were adsorbed in-situ on to the NRLF matrix. Antimicrobial activities were tested by qualitatively and quantitatively against Gram positive Staphylococcus aureus and Gram negative Escherichia coli. It was found that the resultant NRLF samples inhibit the growth of so called two main groups of bacteria in very strong manner. The SEM and EDX analysis provided evidence of adsorbed silver particles on the foam rubber matrix are in nanometer size.

Adsorption of Rhodamine B Dye on Elaeis guineensis Frond Fiber

Adsorption of Rhodamine B (RB) dye was investigated using raw Elaeis guineensis frond fiber (EGFF). Experiments were performed using face centered composite statistical design with six input parameters namely pH (2-10), agitation speed (150-300 rpm), initial dye concentration (100-500 mg/L), temperature (27-80°C), contact time (10-40 min), and adsorbent dosage (0.5-1.5 g). Particle size of < 45 μm was taken as a fixed input parameter. Regression analysis showed good fit of the experimental data to the second-order polynomial model with coefficient of determination (R2) value of 0.99 and 0.98 for color removal and chemical oxygen demand (COD) reduction, respectively. Two optimum operating conditions for the adsorption of RB were found using RSM, resulted in > 99% of color removal and > 97% of COD reduction. The adsorption process was rapid and fitted to the pseudo-second-order kinetic model, while equilibrium data were favorably described by the Langmuir isotherm. The adsorbent showed excellent reusability with 0.1 M NaOH solution as desorbing agent. The findings make EGFF a promising and low-cost adsorbent for the removal of RB from aqueous solutions.

Optimization of the column studies into the adsorption of basic dye using tartaric acid-treated bagasse

AbstractPrevious batch studies have shown that acid treated bagasse is a potentially useful adsorbent for treating dye wastewaters. The present paper examines the use of tartaric acid-modified bagasse for the continuous adsorption of methylene blue (MB) dye in columns. The adsorbent was characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. A 23 full factorial design analysis was carried out to screen the significant parameters that affecting the adsorption of MB dye onto tartaric acid-modified bagasse, namely initial MB concentration (100–300 mg/L), column bed height (40–80 mm), and feed flow rate (5–15 mL/min). The adsorption process was optimized using response surface methodology -central composite design with the help of Minitab® 14 software. Maximum decolorization (99.42%) and chemical oxygen demand reduction (88.40%) could be achieved at 200 mg/L inlet MB dye concentration with 78 mm bed height and 3.5 mL/min of feed flow rate. Thomas and Yoon–Nelson models we...

Storage studies of bread prepared by incorporation of the banana pseudo-stem flour and the composite breads containing hydrocolloids

White bread (BCtr), bread incorporated with banana pseudo-stem flour at 100 g/kg level (B10BPF), and B10BPF added with hydrocolloids at 8 g/kg (based on flour basis), i.e. xanthan gum (B10BPFXG) or sodium carboxy-methyl cellulose (B10BPFCMC) were determined for moisture, water activity, texture, thermal, and microbiological quality during storage (3 days). Results indicated that all the formulated bread crust showed an increase in moisture and water activity during storage, but was vice versa for the respective bread crumb. All the formulated breads showed an ultimate trend in hardness with time. The composite bread crumbs with the exception of B10BPFCMC were observed to be harder than the BCtr. Composite breads showed higher onset and peak temperatures values than BCtr. BCtr had higher gelatinization enthalpy change temperature than composite breads with the exception of B10BPFCMC. Population of aerobic plate counts, mould and yeast count was observed increasing with the time of storage.

Novel Method of Incorporating Silver Nanoparticles into Natural Rubber Latex Foam

Silver nanoparticles (SNP) incorporated potassium oleate (KOL) soap by in situ reduction of silver nitrate by trisodium citrate (TSC) was described. Novel incorporation method of SNP into the natural rubber latex foam (NRLF) was successfully carried out by mixing 4 parts per hundred rubber (pphr) of SNP incorporated KOL soap in to the natural rubber latex (NRL) compound. UV-Visible spectrophotometer analysis, particle size analysis data and transmission electron micrograph analysis proved the modified KOL soap consisted of stable mono-dispersed nanometer size silver particles. SEM/EDX analysis of a latex film made out with modified NRL compound by SNP incorporated KOL soap shows nanosized silver particles inside it. Modified KOL and final product of modified NRLF by SNP incorporated KOL soap tested for antimicrobial properties against Escherichia coli (E. coli). The resultant KOL itself can inhibit Gram negative E. coli bacterium in a very strong manner. Inhibition of the same strain of E. coli bacterium by modified NRLF showed positive result.

In-vitro digestibility and amino acid composition of soy protein isolate cross-linked with microbial transglutaminase followed by heating with ribose

Cross-linked soy protein isolate (SPI) gels were produced via single-treatment of SPI with microbial transglutaminase (MTG) for 5 h or 24 h, or with ribose for 2 h, or via combined-treatments of SPI with MTG followed by heating with ribose. Assessment of gel strength and solubility concluded that measures which increased protein cross-links resulted in improved gel strength; however, in most cases the digestibility and amino acid content of the gels were reduced. The combined treated gel of SPI/MTG for 24 h/ribose was more easily digested by digestive enzymes and retained higher amounts of amino acids compared with the control Maillard gels of SPI with ribose. MTG consumed lysine and glutamine and reduced the availability of amino acids for the Maillard reaction with ribose. MTG was able to preserve the nutritional value of SPI against the destructive effect of the Maillard reaction and cross-links.