Anticancer activity studies of some cyclic benzimidazole derivatives

New benzimidazole derivatives, namely, (N-(4-methoxyphenyl)methylene]-1H-benzimidazol-2-amine (2a), (N-(3,4-dimethoxyphenyl)methylene]-1H-benzimidazol-2-amine (2b), and (N-(3,4,5-trimethoxyphenyl)methylene]-1H-benzimidazol-2-amine (2c) were synthesized by reaction of a Schiff base with malononitrile in absolute ethanol. Structures of compounds have been confirmed by IR, 1H NMR and elemental analysis. Compounds 2a-c were screened for their in vitro anticancer potential using HeLa and PC3 cells. All compounds showed limited cytotoxicity except compound 2a that showed a moderate cytotoxic effect towards HeLa cells

Effect of fiber loading on tensile properties of cocoa pod husk fibers reinforced thermoplastic polyurethane composites

In this study, cocoa (Theobroma cacao) pod husk (CPH) fiber reinforced themoplastic polyurethane (TPU) was prepared by melt blending method using Haake Polydrive R600 internal mixer. The composites were prepared with different fiber loading: 20%, 30% and 40% (by weight), with the optimum processing parameters: 190°C, 11 min, and 40 rpm for temperature, time and speed, respectively. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Increase of fibre loading showed increase in tensile strength and modulus and decreasing trend of strain

Effect of fiber loading on mechanical and morphological properties of cocoa pod husk fibres reinforced thermoplastic polyurethane composites

In this study, cocoa (Theobroma cacao) pod husk (CPH) fiber reinforced thermoplastic polyurethane (TPU) was prepared by melt compounding method using Haake Polydrive R600 internal mixer. The composites were prepared with different fiber loading: 20%, 30% and 40% (by weight), with the optimum processing parameters: 190 °C, 11 min, and 40 rpm for temperature, time and speed, respectively. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Effect of fiber loading on mechanical (i.e. tensile, flexural properties and impact strength) and morphological properties was studied. TPU/CPH composites showed increase in tensile strength and modulus with increase in fiber loading, while tensile strain was decreasing with increase in fiber loading. The composite also showed increase in flexural strength and modulus with increase in fiber content. Impact strength was deteriorated with increase in fiber loading. Morphology observations using Scanning Electron Microscope (SEM) showed fiber/matrix good adhesion

Optimization of processing parameters and fiber content of cocoa pod husk fiber-reinforced thermoplastic polyurethane composites by Taguchi method

A composite of cocoa (Theobroma cacao) pod husk (CPH) fiber reinforced themoplastic polyurethane (TPU) was prepared by melt-blending method followed by compression moulding. Specimens were cut from the sheets that were prepared by compression moulding. The criteria of optimization was testing the specimens by tensile test and comparing the ultimate tensile strength. The aim of this study is to optimize processing parameters and fiber loading using Taguchi approach. These four parameters were investigated in three levels each. The L9 orthogonal array was used based on the number of parameters and levels that have been selected. Furthermore ANOVA was used to determine the significance of parameters. The processing parameters chosen for this study were temperature, speed and time of processing and fiber content. The results showed that optimum values were 190°C, 40 rpm, 11min and 30% for processing temperature, processing speed, processing time and fiber content; respectively. Using ANOVA; fiber content showed the highest significance value followed by processing time. Processing temperature and speed showed no significance in the optimization of TPU/CPH

4,4′-[(1,3,4-Thia­diazole-2,5-di­yl)bis­(thio­methyl­ene)]dibenzonitrile

The title mol­ecule, C18H12N4S3, consists of three essentially planar fragments, viz. two methyl-substituted benzonitrile rings and a substituted thia­diazole ring. The dihedral angles between the substituted benzonitrile rings and the central thia­diazole ring are 28.29 (10) and 78.83 (6)°, and the dihedral angle between the two benzonitrile rings is 72.89 (7)°

Behaviour of Thermal Degradation of Some Poly (4-amino-2,6-pyrimidinodithiocarbonate) Metal Complexes

The thermal decomposition behaviour of the Fe(II), Co(II) and Ni(II) complexes of poly[4-amino-2,6-pyrimidinodithiocarbamate] has been investigated by thermogravimetric analysis (TGA) at a heating rate of 10°C min-1 under nitrogen. The Coats-Redfern integral method is used to evaluate the kinetic parameters for the successive steps in the decomposition sequence observed in the TGA curves. The processes of thermal decomposition taking place in the three complexes are studied comparatively as the TGA and DTA curves indicate the difference in the thermal decomposition behaviour. The thermal stabilities for the release of the fragments at the successive steps in the sequential decomposition of these complexes are discussed in terms of electronegativity and ionic size effects. The difference in thermal stability and the inconsistent variation in the kinetic parameters of these complexes are considered

Natural fiber-reinforced composites: types, development, manufacturing process, and measurement

Natural fiber-reinforced polymer composites offer huge benefits in terms of weight and cost savings, and therefore has been employed in numerous automotive interior and exterior parts. Precision cutting of the composite parts is important to minimize material loss with better surface finish. This paper focuses on the types and manufacturing of composites with machinability characteristics of fiber-reinforced composite. Finally, the study concerns the employment of gray relational analysis to determine the optimized cut characteristics in precision cutting of cocoa pod husk fibers-reinforced thermoplastic polyurethane composites. The cut characteristics, namely kerf width (material loss) and surface roughness (surface finish) are optimized as a function of blade speed, feed rate of the blade, and cocoa fiber loading in the composite. A central composite design method is used to determine the multi-performance characteristics of cut using precision linear saw. The set of the optimized processing parameters is determined based on the highest grade at minimum feed rate (12.1 mm s–1), minimum blade speed (2500 rpm), and minimum fiber content (20% by weight). The influence of each parameter on cut quality is also discussed where the effects of feed rate and blade speed were more significant as compared to the fiber content

Optimization of blending parameters and fiber size of kenaf-bast-fiber-reinforced the thermoplastic polyurethane composites by Taguchi method.

“Kenaf-fibers- (KF-)” reinforced “thermoplastic polyurethane (TPU)” composites were prepared by the melt-blending method followed by compression molding. Composite specimens were cut from the sheets that were prepared by compression molding. The criteria of optimization were testing the specimens by tensile test and comparing the ultimate tensile strength. The aim of this study is to optimize processing parameters (e.g., processing temperature, time, and speed) and fiber size using the Taguchi approach. These four parameters were investigated in three levels each. The L9 orthogonal array was used based on the number of parameters and levels that has been selected. Furthermore, analysis of variance (ANOVA) was used to determine the significance of different parameters. The results showed that the optimum values were 180°C, 50 rpm, 13 min, and 125–300 micron for processing temperature, processing speed, processing time, and fiber size, respectively. Using ANOVA, processing temperature showed the highest significance value followed by fiber size. Processing time and speed did not show any significance on the optimization of TPU/KF

Optimizing processing parameters and fiber size for kenaf fiber reinforced thermoplastic polyurethane composite

In this study, composite of Themoplastic polyurethane (TPU) reinforced with short fiber (Hibiscus Cannabinus) kenaf (KF) were prepared via melt blending method using Haake Polydrive R600 internal mixer. Effect of various processing temperatures, times and speeds on tensile strength was studied, together with effect of various fiber sizes on tensile, flexural properties and impact strength. Optimum blending parameters were 190°C, 11 min, and 40 rpm for temperature, time and speed, respectively. Using the optimum processing parameters TPU-KF composites with different fiber sizes were prepared. Composite sheets were prepared by hot press machine at 190 °C for 10 min. Five samples were cut from the composite sheet. Mean value was taken for each composite according to ASTM standards. Tensile and flexural strength were best for fibers between 125-300 micron. Impact strength showed an increasing trend with increasing fiber size

Natural fibre-reinforced Thermoplastic starch composites

Increasing awareness among the world population of the need to protect the environment has motivated research on agricultural residues. This is due to the abundant sources of agricultural crop wastes that cause handling problems. Agricultural crop residues such as oil palm, pineapple leaf, banana and sugar palm are produced on the scale of billions of tons around the world. They are available in abundance, at low cost, and they are also renewable sources of biomass. Hence natural fibres are potential sources in the design of new green materials associated with polymer matrices. Recently, sugar palm fibre has become the most popular reinforcement material for researchers owing to its high durability. It is important to note that biopolymers that act as a matrix can be produced from the sugar palm tree itself. This chapter reports the preparation of an environmentally friendly composite where the matrix (sugar palm starch) and fibre (sugar palm fibre) are derived from one source, the sugar palm tree. The resulting materials are termed "biocomposites" or " green" composites, and are considered to be totally biodegradable