VOLUME 41, NO3, JUNE-2019
12
 
Graphene Nanoplates Filled Nylon 6,6 Nanocomposites, Morphological, Thermal, Mechanical and Solvent Uptake Study

Khalid Saeed, Tariq Shah and Ahmad Hassan

Effect of graphene nanoplates (GNPs) on the properties of Nylon 6,6 (Nyl 6,6) is investigated in present study. The morphological studies presented that the GNPs were dispersed inside the Nyl 6,6 matrix. The thermo gravimetric analysis (TGA) illustrated that the thermal degradation of nanocomposites samples were started at the range of 350-393 oC, which was appreciably higher than neat Nyl 6,6 (360 oC). The differential scanning calorimetry (DSC) analyses revealed that the crystallization temperature (Tc) of GNPs/Nyl 6,6 increased as increased the addition of GNPs, which might be due to the nucleation effect of GNPs. The mechanical properties of Nyl 6,6 was enhanced by incorporation of GNPs upto the addition of an optimal quantity of filler (5%wt GNPs) into the polymer matrix. The stress yield and Young’s modulus of 5%wt GNPs/Nyl 6,6 was 96.79 and 1.54, N/nm2, respectively. Both Nyl 6,6 and nanocomposites samples were also used for the adsorption of Neutral red chloride (NRC) dye, which significantly remove the dye from the aqueous solution. The neat nylon 6,6 and GNPs (5 and 10 wt%)/Nyl 6,6 adsorbed about 88.49, 93.15, and 93.60% within 2 h, respectively.
Pages(388)
Download
Non-Isothermal Crystallization Kinetics of Graphene Oxide-Carbon Nanotubes Hybrids / Polyamide 6 Composites

Zhi-Qiang Wang, Yong-Ke Zhao and Xiang-Feng Wu

The hybrids combined by nano-materials with different dimensions usually possess much better enhancement effects than single one. Graphene oxide-carbon nanotubes hybrids / polyamide 6 composites has been fabricated. The non-isothermal crystallization kinetics of the as-prepared samples was discussed. Research results showed that increasing the cooling rate was in favor of increasing the crystallization rate and the degree of crystallinity for the as-prepared samples. Moreover, the crystallization rate was first decreased and then increased with increasing the hybrids loading. Furthermore, the crystallization mechanism was changed with increasing the crystallization temperature and the cooling rate. The nucleation and growth modes of the non-isothermal crystallization could be classified into three different types, according to the Ozawa’s theory. These complicated results could be attributed to the important role of crystallization rate as well as the simultaneous hindering and promoting effects of the as-prepared hybrids. This work has reference values for understanding the crystallization kinetics of the polyamide 6-based composites.
Pages(394)
Download
Role of Trace & Toxic Elements in the Development of Anaemia in School going population of Hyderabad

Junaid Ali Thebo, Shaista Khan, Abdul Aziz Shaikh, Nasren Thebo, Ghulam Nabi, Nehwish Lohdi, Muhammad Hassan Khaskheli and Ghulam Abas Shar

The aim of this research work was to measure the concentration of essential trace elements, including serum copper, iron and zinc in children suffering from anemia, and also to investigate the effect of heavy metal like lead on causing anemia. The study has been performed on school going children living in Hyderabad, which is a mini industrialized city. The study was carried out in anemic children studying in different schools of Hyderabad having different age groups. 10 ml venous blood samples were obtained after an informed consent form was signed.The samples were used to analyzed the trace elements (Fe,Cu, Zn) and toxic metal Lead (Pb). Trace elements include zinc and copper were found elevated in anemic children than healthy one, Copper is involved in many vital mechanisms in the body, energy production, connective tissue formation, and Fe metabolism, whereas copper found low with relation to the iron in anemic children because copper helps in the absorption of iron. Zinc is an essential micronutrient demanded by living being because of its significant position in-cooperation with structural constituent of proteins and as a cofactor in enzyme catalysis, there is difference between zinc and iron, they have been found to inhibit each other’s absorption due to their competitive absorption pathways. Increased zinc levels found in children with low iron content, whereas control group have normal results of these elements which may be due to their dietary management. The results revealed the environmental pollution and the associated health risks on exposure to lead. Pb concentrations whereas the current research stated a considerable relationship of mild and severe anemia with 10-42.2μg/dl Pb concentrations, the variation in results may be due to a small sample size in the current study, Drinking water from corrosion of plumbing systems through the use of lead sellers and other lead containing materials in connecting household plumbing to public water supplies. Ground and surface water are also contaminated by lead consuming industry and agricultural activities. The concentrations of Pb greater than or equal to (≥)10 μg/dl in children related with an increased threat of mild and severe anemia, diminishing iron absorption . High Lead levels were related with lower concentrations of iron, ferritin and copper, in this study it was found that high levels of lead were found mostly in boys. Lead levels have also found in control group which was below 5 ug/dl, according to WHO ≥ 10 ug/dl is considered as high.
Pages(405)
Download
Optimization of Production Parameters of Tobacco Seed Oil Methyl Ester using Multi-Response Taguchi Method and MANOVA

Hülya Karabaş, Semra Boran and Harun Resit Yazgan

There is a growing recognition that using of biodiesel in large commercial systems based on sustainability, existing resources and residues can help to natural resources. Tobacco seed oil (TSO) is also used for biodiesel production as a non-edible vegetable oil. A crude oil was obtained from tobacco seeds (TS) and then tobacco seed oil methyl ester-TSOME (biodiesel) was obtained by a transesterification process. In this study, we aimed to achieve optimal biodiesel properties based on different factors using multi response Taguchi method and multivariate analysis of variance (MANOVA). The purpose of the process was to meet a European Biodiesel Standard EN 14214. Properties of the biodiesel (responses) were determined as methyl ester quantity, kinematic viscosity, density, flash point of methyl ester and freezing point of methyl ester. The factors (production parameters) were chosen such as catalyst type, alcohol/oil molar ratio, reaction temperature and catalyst amount for experiment design. The factors that influenced the desired properties were determined using MANOVA. The factors’ level was obtained using a multi response Taguchi method. We found that catalyst type and catalyst amount have a significant effect on the responses and their levels must be level 1(KOH) and level 3 (1.5%) respectively. Thereby the methods provided to produce biodiesel meet requirements of the standard with minimum cost and in short time.
Pages(414)
Download
Synthesis, Characterization of Poly(1,4–cyclohexanedimethylene oxalate) and the Study of its Metal Uptake Behavior Towards Pb(II), Zn(II), and Cd(II) Ions

Yousef A. Al-Dalahmeh, Fawwaz I. Khalili, Bassam A. Sweileh

Poly(1,4–cyclohexanedimethylene oxalate) was synthesized from oxalyl chloride and cis/trans–1,4–cyclohexandimethanol. The polymer was characterized by viscosity, FT–IR, NMR, elemental analysis, DSC, TGA, and SEM. The metal uptake behavior of the polymer towards Pb(II), Zn(II) and Cd(II) ions was studied by batch technique as a function of pH, temperature, concentration, contact time and by column technique. Their uptake increases slightly with pH reaching maximum at 6.00. The order of adsorption capacity was: Pb(II) > Cd(II) > Zn(II). The uptake of the polymer shows fittings to both Langmuir’s and Freundlich equations. ΔG°, ΔH° and ΔS° were determined for Pb(II). The metal-unbound polymer was regenerated by treating the metal-sorbed polymer with 1.0 M HNO3 >1.0 M HCl >0.01 M EDTA.
Pages(421)
Download
Formulation of an Unprecedented Potassium Thiadiazolate Framework Via In-Situ Ligand Synthesis

Saghir Abbas, Manzar Sohail, Muhammad Arif Nadeem, Javaid Hussain Zaidi and Saqib Ali

The development of extended structures using s-block metal centres is fairly rare because of the predominance of ionic forces at metal center. The in-situ formation of 1,3,5-thiadiazole-2,5-dithiol ligand and its coordination to potassium metal ions results in the form of air stable green crystals of a novel framework [C2HKN2OS3]. The two-dimensional framework is characterized as P21 space group with the potassium ion, being heptacoordinated. The compound, showed distorted pentagonal bipyramidal coordination geometry due to the larger cationic radius of the potassium. The potassium metal ion is forming a bond with a nitrogen atom of azine nitrogens, two bonds with the oxygen atoms of the two hydroxyl ions and four bonds with the four sulfide ions of thiol moieties of four different thiadiazole rings. The C-S bond distances are in the range of 1.687(4) to 1.760(4) slightly shorter than the ideal value of 1.77 Å for a C(sp2)-S single bond. The thermogravimetric analysis indicates that a successive loss of the ligand occurs in the range of 253.06 oC to 357.53 oC that infers the stability of the compound.
Pages(437)
Download
Investigation of Mechanical and Electrochemical Performance of Multifunctional Carbon-Fiber Reinforced Polymer Composites for Electrical Energy Storage Applications

Atif Javaid, Ahmad Shahzaib, Hammad Tahir, Munazza Ali, and Wajiha Younus

Concept of structural supercapacitors, based on carbon fiber reinforced polymer composites, has been introduced that can act as a structural load bearing component as well as an electrical energy storing device simultaneously. This multifunctional carbon fiber reinforced structural supercapacitors are fabricated by using carbon fiber and glass fiber/filter paper as reinforcements and cross-linked polymer electrolyte as a matrix. Carbon fiber mats also simultaneously serve the role of electrodes in addition to reinforcements whereas the glass fiber mat/filter paper also acts as an insulator to avoid the short-circuiting of the carbon fiber electrodes. A polymer epoxy matrix is modified by introducing ions within the cross-linked structure in order to develop an optimized polymer electrolyte. Flexural tests of structural supercapacitor are conducted to evaluate the structural performance while charge/discharge tests are conducted to evaluate the electrochemical performance. Multifunctional structural supercapacitors are tested mechanically as well as electrochemically. A structural supercapacitor is fabricated showing simultaneously an energy density of 0.11 mWh m-3, a specific capacitance of 0.8 mF.cm-3 and a flexural modulus of 26.6 GPa simultaneously.
Pages(444)
Download
Synthesis and Crystal Structures of 3,6-diacetylated C24 epimeric 20(R)-Ocotillol-Type Saponins

Juan Liu, Wen-Zhi Wang, Jia-Zhen Wang, Gui-Ge Hou, Qing-Guo Meng

(20R,24R)-epoxy-dammar-3β,6α,12β,25-tetraol (1) and (20R,24S)-epoxy- dammar-3β, 6α,12β,25-tetraol (2) have been synthesized from 20(R)-protopanaxatriol with same polarity. In order to obtain optically pure 1 and 2, (20R,24R)-3,6-diacetyl- 20,24-epoxydammar-3β,6α,12β,25-tetraol (3) and (20R,24S)-3,6-diacetyl-20,24- epoxydammar-3β,6α,12β,25-tetraol (4) were designed and prepared to enhance the polarity difference of C24 epimers. Two suitable crystals of 3 and 4 were obtained and their structures were determined by 1H NMR, 13C NMR, HR-MS and X-ray single-crystal diffraction. The results indicated that the C-24 configuration of 3 and 4 are R-form and S-form, respectively. 3 has two intramolecular hydrogen bond. While there is only one in 4 and the crystal stacking displays that it generates a right-handed helically chiral channel viewing from the crystallographic b axis via classical O–H•••O intermolecular hydrogen bond.
Pages(452)
Download
Jatropha curcas L.: A Non-food Oil Source for Optimized Biodiesel Production

Tahir Mehmood, Adeela Naseem, Farooq Anwar, Mudassir Iqbal and Muhammad Ashraf Shaheen

Response Surface Methodology (RSM) was applied based on central composite rotatable design (CCRD) to optimize transesterification reaction parameters for obtaining optimal biodiesel yield from Jatropha curcas oil. Transesterification variables such as: catalyst concentration (CC) (0.16-2%), reaction temperature (RT) (40-65°C), molar ratio of oil and methanol (0.95-11.5), and reaction time (30-140 min) were optimized via RSM involving 24 full factorial CCRD design. The molar ratio of methanol to oil and RT were the most significant (p< 0.5) factors affecting the yield of Jatropha curcas oil methyl esters (JOMEs). A linear relationship was recorded between the observed and predicted values (R2 = 0.766). Using multiple regression analysis, a quadratic polynomial equation was constructed to predict JOMEs yield. The quadratic term of molar ratio showed a significant impact on the JOMEs yield. The interaction terms of molar ratio and CC with reaction time exhibited positive impact on ester yield (p< 0.05). The optimum reaction conditions including CH3OH to oil ratio of 6:1, 1.0 % CC, 60 °C RT and 60 min reaction time offered the highest yield of JOMEs (99.90%). JOMEs were analytically characterized using GLC and FTIR. The fuel properties of produced JOMEs were in accordance to ASTM D6751 and EN 14214 standards.
Pages(458)
Download
Orodispersible Films of an Antipsychotic Drug: Development and Physicochemical Characterization

Muhammad Naeem Aamir, Aneela Manzoor, Hina Hussain, Zeeshan Javaid, Tariq Mahmood , Khizar Abbas, and Akhtar Rasul

To deliver maximum amount of paroxetine in shortest duration of time, the orodispersible films (ODF) were formulated and tested for their suitability as a carrier system. ODF were prepared by using hydroxypropyl methylcellulose and polyvinyl alcohol and different superdisintegrants at a specific proportion. The newly developed ODF were subjected to characterization for folding endurance, weight variations, thickness, disintegration time, drug release pattern and drug content. The surface morphology of orodispersible film was examined by means of scanning electron microscope. Moreover physical compatibility between the drug and excipients was guaranteed in the orodispersible film by Fourier transform infrared spectroscopy. It was found that all films prepared were transparent, smooth and elegant in appearance. ODF showed good folding endurance, uniform thickness, weight and drug content. The surface pH of all orodispersible film was found to be neutral and they disintegrate within few seconds. FTIR spectroscopy supported compatible among all excipients and they can be used together in formulation. It was concluded that stable paroxetine orodispersible films can be made by solvent casting technique with ultrafast dissolution rate.
Pages(469)
Download
12

 

Browse By Issue