Chemical conversion of PET waste using ethanolamine to bis(2-hydroxyethyl) terephthalamide (BHETA) through aminolysis and a novel plasticizer for PVC

Poly(ethylene terephthalate) (PET) recycling has been carried out by various methods, e.g., mechanical recycling, chemical recycling and energy recovery method. In this study, chemical recycling of PET was carried out by aminolysis using ethanolamine and converted into bis(2-hydroxyethyl) terephthalamide (BHETA). The reaction was performed by varying the PET:ethanolamine ratio, reaction time and catalyst used for waste medical grade bottles of PET. Yield of about 81 % was obtained for PET:ethanolamine ratio of 1:4 (w/w), with 3 h reaction time, at 160 °C with zinc acetate as a catalyst. BHETA was characterized with FTIR, ¹H NMR, and DSC analysis. BHETA was further reacted with heptanoic acid at a molar ratio of 1:2.5. The product obtained was used as a plasticizer for PVC at 5, 10, 15 and 20 parts per hundred (phr) concentration. Thermal and mechanical tests were carried out and the result obtained was compared with the virgin PVC without plasticizer and with conventional plasticizer of PVC, i.e., dioctyl phthalate at 15 phr concentration since new plasticizer showed excellent properties at 15 phr concentration. This newly synthesized plasticizer was completely fused with PVC and in tensile testing helped in increasing the elongation, which was an indication of the plasticization effect shown by this developed material. Glass transition temperature also decreased with an incorporation of the new plasticizer as compared to virgin PVC.     

Studies on auramine dye adsorption on psidium guava leaves

Removal of auramine dye from aqueous waste solutions was investigated by using very cheap and biosorbent, withered guava tree leaves and activated carbon. Guava leaves are readily available in the western and northern parts of India throughout the year, and hence form a cost effective alternative for removal of dyes from waste waters. The optimum contact time was found to be 120 min. in a pH range of 8–9 for 92–94% removal of the dye from aqueous solutions containing 150 mg/L of auramine dye using 2 g of the adsorbent. The effect of pH, dye concentration, sorbent dosage, temperature and contact time on the dye removal efficiency has been studied. Experimental results were found to fit both Freundlich and Langmuir models. Since the dye contains a cationic species, the removal efficiency was highest in a pH range of 8–9. Continuous adsorption studies in a packed column showed 100% removal efficiency for a flow rate of 10 ml·min⁻¹. When compared with the activated carbon, it was also found that adsorbent derived from guava leaves is more efficient in removal of dye.     

Application of aerosol‐spray deposition for determination of fine structure of barley starch using atomic force microscopy

Starch samples extracted from barley cultivars with varying AM concentrations were imaged by AFM using intermittent contact mode. Two different deposition methods were used: a simple solution drop and an aerosol spray deposition. Using the drop deposition method, starch appeared mainly as small particles and aggregated globules, with average heights of 1.8 ± 0.2, 2.7 ± 0.7, and 5.5 ± 1.0 nm, for starch solutions containing increased (38%), normal (25.8%), and undetectable (0%) AM, respectively. The aerosol spray deposition method allowed analysis of individual biopolymer chains of AM and biopolymer fibrils of AP. The image of normal starch showed individual AM chains with an average height of 0.8 ± 0.2 nm, and an average contour length of 178 ± 127 nm. For increased AM starch, the height of individual AM chains was similar to normal starch, but the average contour length was shorter (140 ± 70 nm). All barley starches showed fibril bundles of AP with average heights of 1.9 to 2.9 nm and lengths in the micron size range.     

Silicon nanoelectronics and beyond: An overview and recent developments

This year marks the 40th anniversary of the invention of the first beam-lead device by Lepselter et al. Lepselter and coworkers proposed a method of fabricating a new semiconductor device structure and its application to high-frequency silicon switching transistors and ultra-high-speed integrated circuits. Beam-lead technology, also known as air-bridge technology, has established itself for its unsurpassed reliability in high-frequency silicon switching transistors and ultra-high-speed integrated circuits for telecommunications and missile systems. The beam-lead device became the first example of a commercial microelectromechanical structure (MEMS). Since its inception, MEMS has taken advantage of the evolving silicon technology, resulting in today’s nano-electromechanical structure and nano-optomechanical structure. In this paper, an overview of recent developments of silicon nanoelectronics is presented. For more information, contact N.M. Ravindra, New Jersey Institute of Technology, Interdisciplinary Program in Materials Science and Engineering, Department of Physics, Newark, New Jersey 07102; (973) 596-3278; fax (973) 642-4978; e-mail nmravindra@comcast.net.     

Genotype and growing environment influence chickpea (Cicer arietinum L.) seed composition

BACKGROUND: As a first step towards genetic improvement of seed quality in chickpea (Cicer arietinum L.), seven desi and nine kabuli varieties were grown at multiple sites to assess the affect of environment on seed yield, weight and selected seed constituents. The sites were chosen to represent a range of environments in chickpea production areas of the Canadian prairies. RESULTS: Genotype × environment interaction effects on starch, amylose and protein (desi only) concentrations and seed yield were significant, suggesting that the varieties did not perform consistently relative to each other in the different environments. Starch concentration was negatively correlated (r_kabuli = ?0.25, P < 0.05; r_desi = ?0.16, P < 0.05) with protein concentration in both chickpea market classes. However, repeatability estimates of starch, amylose and protein concentrations were low and inconsistent across chickpea market classes, possibly owing to complex biosynthetic pathways for these constituents. CONCLUSION: The results suggest that testing for seed constituent traits over a range of environments will be required to improve seed quality in individual chickpea varieties. The best selection strategies for seed constituent improvement in chickpea will be influenced by genotype and genotype × environment interaction for these traits. The negative relationship between seed constituents and yield indicates that selection for chickpea cultivars with desired seed composition may require compromise and indirect selection. Copyright © 2009 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.     

Infrared Spectroscopic Method for Determination of Thermal Properties of Fluorophosphate Glasses

Fluorophosphate glasses of the Ba(PO₃)₂–MgF₂–CaF₂–AlF₃ system exhibit anomalous behavior, in regard to the glass-transition temperature ( T _g) and the coefficient of thermal expansion (α_CTE), at a fluoride concentration of ∼36 mol%. A similar trend in the infrared band absorption coefficient (α_IR) at 2170 cm⁻¹ of the overtone of 2ν_ss(OPO) and/or a combination of ν_as(OPO)+ν_as(POP) fundamental vibrations of PO₄ tetrahedra also has been observed, relative to changes in the glass composition. Statistical analyses have shown that the T _g and α_CTE values are correlated with α_IR at 2170 cm⁻¹ by linear equations. The thermal properties of some of the glasses have been calculated using these equations, to test their validity and utility. The experimental property values of the glasses present a very good fit of data within a 95% confidence interval of the calculated mean values.     

Intumescent coatings: A review on recent progress

Fire is a serious threat to people and the structures they build. There is a continuous development of newer methods and materials to prevent its effects on them. Nowadays, a lot of attention is being paid in the design of public and commercial buildings by incorporating fire safety. Passive fireproofing of high-rise structures has become very important due to the use of steel in load bearing mode and has attracted increased attention after the collapse of the WTC towers. Conventional passive fireproofing materials include concrete covering, gypsum board and cementitious coatings which have a poor aesthetic. Intumescent fire-resistive coatings are a newer type of passive fireproofing coatings usually applied as thin film and they swell many times their original thickness forming an insulating char which acts as a barrier between the fire and the structural steel. It prevents the temperatures of the steel members from reaching a critical value and helps in maintaining the integrity of the structure in fire event. They are the preferred choice for passive fire protection of load bearing steel frame structures of architects and designers as they offer aesthetic appearance, flexibility, speed of application, and ease of inspection and maintenance. The present review covers recent developments in the field of intumescent coatings with a major emphasis on organic intumescent coatings. The role of various ingredients, their interactions in intumescent coatings, effects of various pigments, binders and additives are discussed briefly.