Investigation of liquid crystalline and photocrosslinkable poly[4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamate]s

Three series of liquid‐crystalline‐cum‐photocrosslinkable polymers were synthesized from 4‐x‐phenyl‐4′‐(m‐methacryloyloxyalkyloxy)cinnamates (x = ? H, ? OCH₃ and ? CN; m = 6, 8 and 10) by free radical solution polymerization using azobisisobutyronitrile as an initiator in tetrahydrofuran at 60 °C. All the monomers and polymers were characterized using intrinsic viscosity, and FTIR, ¹H NMR and ¹³C NMR spectroscopy. The liquid crystalline behavior of these polymers was examined using a hot stage optical polarizing microscope. All the polymers exhibited liquid crystalline behavior. The hexamethylene spacer‐containing polymers exhibited grainy textures; in contrast, the octamethylene and decamethylene spacer‐containing polymers showed nematic textures. Differential scanning calorimetry data confirmed the liquid crystalline property of the polymers. Thermogravimetric analysis revealed that all the polymers were stable between 236 and 344 °C in nitrogen atmosphere and underwent degradation thereafter. As the methylene chain length increases in the polymer side‐chain, the thermal stability and char yield of the polymers decrease. The photocrosslinking property of the polymers was investigated using the technique of exposing the polymer solution to UV light and using UV spectroscopy. The crosslinking reaction proceeds via 2π–2π cycloaddition reactions of the ? CH?CH? of the pendant cinnamate ester. The polymers containing electron‐releasing substituents (? OCH₃) showed faster crosslinking than the unsubstituted polymers and those containing electron‐withdrawing substituents (? CN). Copyright © 2007 Society of Chemical Industry     

Multi-block copolymer dispersions through polyurethane macroiniferters

Summary Tetraphenylethane-based polyurethane macroiniferter has been used to prepare polyurethane-polymethacrylic acid multi-block copolymers. These block copolymers have been converted into corresponding anionomers by treating them with triethylamine. Dispersions have been prepared by adding water into dimethylformamide solutions of block copolymers and their anionomers. Particle size and viscosity of the dispersions have been determined. The films obtained from the dispersions have been characterized by mechanical and dynamic mechanical analyses. Received: 18 March 1998/Revised version: 13 April 1998/Accepted: 16 April 1998     

Catalytic decomposition of nitrous oxide over calcined cobalt aluminum hydrotalcites

Catalytic decomposition of nitrous oxide has been carried out over calcined cobalt aluminum hydrotalcites of general formula [Co_1−xAl_x(OH)₂[CO₃]_x/2 H₂O where x = 0.25–0.33 at 50 Torr (1 Torr = 133 Pa) initial pressure of N₂O in a static glass recirculatory reactor (130 cc) in the temperature range 150–280°C. All catalysts showed a first order dependence in N₂O without significant oxygen inhibition. The activity increased with an increase in cobalt concentration present in the sample. The catalyst precursor synthesized under low supersaturation (LS) exhibited a higher activity than the precursor synthesized by sequential precipitation (SP) method. The observed trend in the activity is explained based on the surface concentration of cobalt, determined by XPS and matrix effects. Prior to catalytic studies, the fresh and calcined samples were characterized by various physicochemical techniques such as XRD, FT–IR, TG–DSC, TEM (with EDAX) and BET surface area measurements.     

Supercritical carbon dioxide (scCO2) dispersion of poly(ethylene terephthalate)/clay nanocomposites: Structural,mechanical, thermal,and barrier properties

Dispersed poly(ethylene terephthalate) (PET)/clay nanocomposites can lead to materials with superior barrier and mechanical properties. PET/clay nanocomposites were prepared by melting extrusion of PET with as‐received or supercritical carbon dioxide (scCO₂) predispersed Cloisite^® 30B (30B). The predispersion of 30B was assessed by WAXD, SEM, and TGA, and results indicated that scCO₂ processing could predisperse 30B and the surface modification of the clay was preserved after processing. The structure of PET/30B nanocomposites was investigated by WAXD and TEM confirming that PET has penetrated into the clays inter‐galleries and the predispersed clays lead to improved interfacial interaction and homogenous clay dispersion. Both tensile strength and Young's modulus were improved by 12.1% and 24.9% respectively, as incorporating of 3 wt % of scCO₂ processed clay. Differential scanning calorimetry (DSC) results indicated that clay particles served as nucleation agent could increase the crystallinity whereas had no impact on melting process. In addition, with the addition of 1 wt % of predispersed clay, a significant reduction of oxygen permeation (～33%) was achieved at 23 °C and the maximum reduction (44%) was achieved by adding 3 wt % processed clay. Moreover, we confirmed the effect of temperature on the permeation of PET/30B nanocomposites depended both on the Arrhenius behavior of the organic phases and tortuous path effects, where improved clay dispersion resulted in a higher effective activation energy. Moreover, the transparency of PET matrix was preserved for all nanocomposites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44779.     

Performance analysis of low heat rejection diesel engine,using Mahua oil bio fuel

In the present investigation, the effect of thermal barrier coated piston on the performance and emission characteristics of mahua-biodiesel-fuelled diesel engine was studied and compared with those of neat diesel fuel. The piston, cylinder walls and the valves of the engine were coated with 0.25?mm thickness of Al₂O₃ material without affecting the compression ratio of the engine. Experiments were conducted using diesel and biodiesel blend (B20) in the engine with and without coating. The results revealed that specific fuel consumption was decreased by 8.5% and the brake thermal efficiency was increased by 6.2% for biodiesel blend with coated engine compared with the base engine with neat diesel fuel. The exhaust emissions CO, NO_x and HC emissions were also decreased for biodiesel blend with coated engine compared with base engine.     

Removal of Cu(II) by biosorption onto coconut shell in fixed-bed column systems

Biosorption of Cu(II) onto coconut shell, an agricultural biomaterial, was studied in a fixed-bed column. The Cu(II) biosorption column had the best performance at 10 mg L^?1 inlet Cu(II) concentration, 10 mL min^?1 flow rate and 20 cm bed depth. The equilibrium uptake of Cu(II) amounted to 7.25 mg g^?1. The simulation of the breakthrough curve was successful with the BDST and Yoon–Nelson models, but the entire breakthrough curve was best predicted by the Clark model. The design of a fixed bed column for Cu(II) removal from wastewater by biosorption onto coconut shell can be done based on these models.     

Occurrence of eight bisphenol analogues in indoor dust from the United States and several asian countries: implications for human exposure

Bisphenol A has been reported to be a ubiquitous contaminant in indoor dust, and human exposure to this compound is well documented. Information on the occurrence of and human exposure to other bisphenol analogues is limited. In this study, eight bisphenol analogues, namely 2,2-bis(4-hydroxyphenyl)propane (BPA), 4,4'-(hexafluoroisopropylidene)diphenol (BPAF), 4,4'-(1-phenylethylidene)bisphenol (BPAP), 2,2-bis(4-hydroxyphenyl)butane (BPB), 4,4'-dihydroxydiphenylmethane (BPF), 4,4'-(1,4-phenylenediisopropylidene)bisphenol (BPP), 4,4'- sulfonyldiphenol (BPS), and 4,4'-cyclohexylidenebisphenol (BPZ), were determined in indoor dust samples (n = 156) collected from the United States (U.S.), China, Japan, and Korea. Samples were extracted by solid-liquid extraction, purified by automated solid phase extraction methods, and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total concentrations of bisphenols (∑BPs; sum of eight bisphenols) in dust were in the range of 0.026-111 μg/g (geometric mean: 2.29 μg/g). BPA, BPS, and BPF were the three major bisphenols, accounting for >98% of the total concentrations. Other bisphenol analogues were rare or not detected, with the exception of BPAF, which was found in 76% of the 41 samples collected in Korea (geometric mean: 0.0039 μg/g). The indoor dust samples from Korea contained the highest concentrations of both individual and total bisphenols. BPA concentrations in dust were compared among three microenvironments (house, office, and laboratory). The estimated median daily intake (EDI) of ∑BPs through dust ingestion in the U.S., China, Japan, and Korea was 12.6, 4.61, 15.8, and 18.6 ng/kg body weight (bw)/day, respectively, for toddlers and 1.72, 0.78, 2.65, and 3.13 ng/kg bw/day, respectively, for adults. This is the first report on the occurrence of bisphenols, other than BPA, in indoor dust.     

Mass loading and fate of perfluoroalkyl surfactants in wastewater treatment plants

Wastewater treatment plants have recently been identified as a significant pathway for the introduction of perfluoroalkyl surfactants (PASs) to natural waters. In this study, we measured concentrations and fate of several PASs in six wastewater treatment plants (WWTPs) in New York State. We also monitored and measured matrix effects (ionization suppression and enhancement) by postcolumn infusion and standard additions. Concentrations of perfluorooctanoate (PFOA) in effluents of the six WWTPs ranged from 58 to 1050 ng/L. Perfluorooctanesulfonate (PFOS) was also ubiquitous in effluents of these WWTPs, albeit at much lower concentrations (3-68 ng/L). Two of these WWTPs employed identical treatment processes, with similar hydraulic retentions, but differed only in that Plant B treated domestic and commercial waste, whereas Plant A had an additional industrial influence. We found that this industrial influence resulted in significantly greater mass flows of all of the PASs analyzed. Primary treatment was found to have no effect on the mass flows of PASs. Secondary treatment by activated sludge in Plant A significantly increased (p < 0.05) the mass flows of PFOS, PFOA, perfluorononanoate (PFNA), perfluorodecanoate (PFDA), and perfluoroundecanoate (PFUnDA). However, in Plant B, only the mass flow of PFOA was significantly increased. The observed increase in mass flow of several PASs may have resulted from biodegradation of precursor compounds such as fluorotelomer alcohols, which is supported by significant correlations in the mass flow of PFOA/PFNA and PFDA/PFUnDA. Furthermore, the masses of PFDA and PFUnDA were significantly correlated only after the secondary treatment. In Plant A, concentrations of odd-number PFCAs were greater than those of even-number PFCAs, and concentration decreased with increasing chain length (from C8 to C12). A different pattern was observed in sludge samples, in which the dominance of PFOA decreased, and PFDA and PFUnDA increased, suggesting preferential partitioning of longer-chain PFCAs to sludge.     

Comparative dry matter intake and nutrient utilisation efficiency in lactating cattle and buffaloes

An attempt was made to assess the comparative dry matter intake and nutrient utilisation efficiency of lactating buffaloes and cows based on results obtained from experimental feeding trials conducted in India. Data on dry matter (DM) intake, total digestible nutrient (TDN) intake, digestible crude protein (DCP) intake, body weight or metabolic body size (MBS), body weight change, milk yield or 4% fat‐corrected milk (FCM) yield, milk fat percentage and roughage/concentrate ratio in the diet of lactating buffaloes and cows were collected from published reports. The data were processed and analysed to assess the comparative dry matter intake and nutrient utilisation efficiency using suitable statistical analysis models. DM intake was significantly (P < 0.01) lower in buffaloes (2.57 kg DM per 100 kg body weight or 119.2 g kg^?1 MBS) than in cattle (3.09 kg DM per 100 kg body weight or 132.0 g kg^?1 MBS). Mean gross energetic efficiency (30.53 versus 27.83%; P < 0.01), gross protein efficiency (45.48 versus 37.06%; P < 0.01), net energetic efficiency (69.16 versus 64.10%; P < 0.05) and net protein efficiency (80.15 versus 59.59%; P < 0.001) were significantly higher in buffaloes than in cattle. Lactating buffaloes consumed significantly less (P < 0.001) protein (75.69 g DCP) and less (P < 0.01) energy (695.9 g TDN) than cows (93.89 g DCP, 774.8 g TDN) for production of 1 kg of 4% fat‐corrected milk. Buffaloes had higher energy and protein utilisation efficiencies as compared with cattle at similar fat‐corrected milk production level, plane of energy and protein nutrition, body size and body weight change. Buffaloes (1.189 kg DM kg^?1 4% FCM) consumed a similar (P > 0.05) amount of feed dry matter to that of cows (1.267 kg DM kg^?1 4% FCM). However, when DM intake kg^?1 FCM (4%) was compared at constant levels of metabolic body size, fat‐corrected milk, body weight change, dietary energy concentration and green forage percentage in the diet, lactating buffaloes consumed significantly less DM kg^?1 FCM yield as compared with cattle. It was concluded that DM intake was lower in lactating buffaloes. Moreover, lactating buffaloes utilised dietary dry matter, energy and protein for milk production more efficiently than cattle. © 2003 Society of Chemical Industry