Synthesis and characterization of novel curcumin based polyurethanes varying diisocyanates structure

In this research work, novel polyurethanes (PUs) based on blends of curcumin/1,4-butane diol (BDO) by varying the structure of diisocyanates were prepared following step growth polymerization. Structural study of blends and various diisocyanates based PU through Fourier Transform Infrared (FTIR) spectroscopy confirmed the incorporation of curcumin into the backbone of the PU. The scanning electron microscopic (SEM) study confirmed the well dispersion of incorporated curcumin and homogeneity of surface of synthesized samples. The SEM results also indicated that surface morphology of synthesized samples much dependent on diisocynates structure. Moreover SEM images inferred that phase separation is more pronounced in aromatic diisocyanate based PU. The anti-bacterial and anti-fungal tests were performed against different strains in order to determine the biocompatibility of the curcumin based PU. The antimicrobial activity results revealed that the material having aromatic diisocyanate are more biocompatible than the aliphatic diisocyanates in the PU structure. On the whole, this work is actually a step towards the generation of novel biocompatible materials preferably useful for biomedical applications.     

Buckypapers of polyvinyl chloride/poly(styrene-co-maleic anhydride) blend intercalated graphene oxide-carbon nanotube nanobifiller: Physical property exploration

Novel buckypaper of polyvinyl chloride (PVC) and poly(styrene-co-maleic anhydride) (PSMA) intercalated with carbon nanotube (CNT) and graphene oxide-CNT (GO-CNT) nanobifiller was prepared using resin infiltration technique. Two series of buckypaper were prepared with varying CNT and GO-CNT contents. According to field emission scanning electron microscopy, PVC/SMA/CNT 0.1 showed porous morphology while PVC/PSMA/GO-CNT 0.1 revealed unique sort of island-nodule morphology. T_max of PVC/PSMA/GO-CNT 0.1 was 561°C while PVC/PSMA/CNT 0.1 depicted relatively lower value (552°C). T_g of PVC/PSMA/GO-CNT 0.1 was also increased to 294°C. Peak heat release rate of poly(methyl methacrylate-co-methacrylic acid)/polyamide 6/montmorillonite-modified GO was decreased from 322 to 209 kW/m² (65%) with 0.03–0.3 g GO-CNT loading.     

Auto-recognition and part model complexity quantification of regular-freeform revolved surfaces through delta volume generations

Engineering with Computers - Vast research works implementing feature-based technology have successfully been devoted. However, work on recognition of revolved regular-freeform surfaces is still...     

Influence of fine ceramic aggregates on the residual properties of concrete subjected to elevated temperature

The residual properties of concrete subjected to elevated temperature are of importance to assess the stability of the structure. This paper investigates the performance of concrete containing white ware ceramic sand exposed to elevated temperature. Concrete mixes containing 0%, 50%, and 100% ceramic sand were prepared. The specimen were exposed to elevated temperatures of 200°C, 500°C, and 800°C for a duration of 60 minutes. Their residual mechanical properties (compressive strength, split tensile strength), ultra sonic pulse velocity, and mass change for different cooling regimes were investigated and compared among specimen. The results showed that incorporation of ceramic sand in concrete mixes improved the resistance against elevated temperature of hardened concrete.     

Analyzing readers behavior in downloading articles from IEEE digital library: a study of two selected journals in the field of education

Scientometrics - In this study, we investigate the downloads behavior of readers for two well-known IEEE journals in the field of education, i.e., IEEE Transactions on Learning Technologies (TLT)...     

Martensitic phase transformations in Ni–Ti-based shape memory alloys: The Landau theory

We present a simple Landau free energy functional for cubic-to-orthorhombic and cubic-to-monoclinic martensitic phase transformations. The functional is derived following group–subgroup relations between different martensitic phases – tetragonal, trigonal, orthorhombic and monoclinic – in order to fully capture the symmetry properties of the free energy of the austenite and martensite phases. The derived free energy functional is fitted to the elastic and thermodynamic properties of NiTi and NiTiCu shape memory alloys which exhibit cubic-to-monoclinic and cubic-to-orthorhombic martensitic phase transformations, respectively.     

Insight into the binding of copper(II) by non-toxic biodegradable material (Oryza sativa): effect of modification and interfering ions

The present studies are focused on the use of non-toxic biodegradable straw from Oryza sativa in its simple and modified forms for the binding of copper(II) ions. A relatively new “green” method was adopted for modification with urea under microwaves. The studies have been performed by using the aqueous solution of Cu(II) ions with and without the presence of Cd(II) and Pb(II) as interfering ions. FTIR analysis showed the presence of oxygen- and nitrogen-containing functional groups in simple and modified materials. The emergence of new bands and shifts in the peaks confirmed the modification. The kinetics of the process was studied using the commonly employed mathematical models. Although Elovich model seemed to fit yet coefficient of determination did not reinforce it. Pseudo-second-order model was found to explain the kinetics of the binding of metal ions by simple and modified straw. The equilibrium was studied using the non-linear approach. Based on root mean square error values, it was found that Langmuir model was the most suitable model, followed by Temkin model. Surface areas were compared for single and multi-metal systems. The effect of pH was also studied. Under the studied set of conditions, the modification of straw caused a decrease in the equilibrium time of contact and increase in the biosorption capacities. The presence of other ions decreased the capacities drastically due the competition to bind with the materials.     

Sulfonated Beet Pulp as Solid Catalyst in One-Step Esterification of Industrial Palm Fatty Acid Distillate

In this research a new heterogeneous catalyst has been prepared for biodiesel production. The catalyst was prepared by sulfonating industrial sugar waste. Unlike homogeneous catalysts, which require further purification and separation from the biodiesel production reaction media, this inexpensive synthetic catalyst does not need to go through an additional separation process. This advantage consequently minimizes the total application costs. The catalyst was prepared by partially carbonizing sugar beet pulp at 400 °C. The carbonization product was then sulfonated with concentrated H₂SO₄ vapor in order to produce a solid catalyst. The prepared catalyst was used in the esterification reaction between palm fatty acid distillate (PFAD) and methanol. The effects of the temperature, methanol/PFAD ratio, reaction time and catalyst dosage on the efficiency of the production were individually investigated. The optimum biodiesel production occurred at 85 °C, a reaction time of 300 min, catalyst dosage of 3 g and methanol/PFAD ratio of 5:1 (mol/mol), lowering the acid value from 198 to 13.1 (mg KOH/g oil) or the equivalent, with a fatty acid methyl ester yield of around 92 %. The results suggest that the synthesized inexpensive catalyst is useful for biodiesel production from PFAD.     

Synthesis,characterization and polymerization of novel sugars based on methacrylate

The present study describes the synthesis and characterizations of polymerizable vinyl sugars. Glucose, mannose, galactose and fructose are abundant and sustainable natural compounds. As it is not possible to make many derivatives of sugars without using protective groups, first of all, diacetone derivatives [diacetone-d-glucose (1), diacetone-d-mannose (2), diacetone-d-galactose (3) and diacetone-d-fructose (4)] were synthesized according to the literature as starting compounds. The remaining free hydroxyl groups on C-3 (diacetone glucose), C-6 (diacetone galactose), C-1 (diacetone fructose) and C-1 (diacetone mannose), were reacted with epichlorohydrin (1-chloro-2,3-epoxypropane) to produce then “-O-(2′,3′-epoxypropane-1′-yl)” ether derivatives (5, 6, 7, and 8) which are epoxy sugars in the basic medium. Next, the epoxy rings of the ethers (5, 6, 7, and 8) were opened with methacrylic acid in DMF to produce new sugar based methacrylates (9, 10, 11, and 12). Finally, free radical polymerization of these sugar based methacrylate monomers was performed, producing related polymers (13, 14, 15 and 16). The polymerizations were carried out using AIBN as an initiator at 70 °C in DMF. All the products were characterized by FTIR, ¹HNMR and ¹³CNMR techniques. Thermal properties of all polymers were investigated by TG, DTG and DSC. The data obtained has suggested that thermal stability of the synthesized polymers has changed with the structure of the sugar and increase in molecular weight.