Effect of crystallinity on the kinetics of liquid absorption into poly(ethylene terephthalate)

Drawn poly(ethylene terephthalate) fibers (D.R. 5 : 1) were treated unrestrained in dimethylformamide and benzaldehyde at 100°C for varying amounts of time. A rapid diffusion of liquids into the polymer occurred, the latter experiencing considerable retention of the absorbed liquids at 60°C. The increase in chain mobility brought about by both the liquids absorbed and the liquid-induced crystallisation that followed allowed orientation strains existing in the polymer structure to be relieved. This brought about a 20% shrinkage in the polymer and a change in its overall geometry. Subsequently, a sharp drop occurred in the level of liquid retention within the polymer signifying expulsion of liquids from the crystallising domains and ultimately a levelling off (equilibrium) in the weight retention kinetics. However, precrystallisation of the fibers at 200°C for 3 h using dry hot air prior to liquid treatment study at 100°C and retention at 60°C, led to a linear increase in the amount of liquid retained in the polymer as a function of time until an equilibrium was established. The essential feature of the latter liquid retention kinetic is that a plot of the amount of relative liquid retained, that is M_t/M_∞ as a function of square root of time, () agrees with Fick's standard diffusion process. © 1993 John Wiley & Sons, Inc.     

Remediation of alpha-methylnaphthalene-contaminated sediments using peroxy acid

Laboratory experiments have been conducted to elucidate the degradation of alpha-methylnaphthalene in lake sediments using an advanced oxidation process (AOP) employing peroxy-acids as oxidizing agents. Abiotic degradation of alpha-methylnaphthalene was observed in sediment samples exposed to a 1:1:1 v/v/v mixture of water/organic acid/hydrogen peroxide solution. Sediment samples were collected from Lake Macatawa (Holland, MI) and ranged in total organic carbon content from 2.1% (sandy sediment sample III) to 12.8% (silty-clay sediment sample I) and surface area, which ranged from 3.2m(2)/g (sandy sediment sample III) to 22.0m(2)/g (silty-clay sediment sample I). Analytical measurements performed by gas chromatography revealed varied rates of degradation, depending on the type of acid and the characteristics of the sediment sample. Within 24h, alpha-methylnaphthalene was reduced to 70% and 100% of its original concentration when propionic acid and acetic acid were used as the organic acids, respectively. The formation of products was explored using a gas chromatograph equipped with a mass spectrometer and indicated mainly the formation of lower molecular weight compounds, such as alkyl chains. This AOP method of PAH degradation in sediment/liquid slurry was fast acting and products were most likely biodegradable.     

Antihypertensive properties of aqueous extracts of vegetable leaf‐fortified bread after oral administration to spontaneously hypertensive rats

This study investigated the potential cardiovascular health benefits of leavened bread produced from wheat flour that contained 1%, 2% and 3% additions of leafy vegetable powders obtained from Amaranthus viridis (AO), Solanum macrocarpon (SM) or Telfairia occidentalis (TO). Dried breads were extracted with water at 60 °C followed by analysis for total polyphenolic content (TPC), as well as in vitro inhibitions of angiotensin‐converting enzyme and renin activities. HPLC analysis of the bread extracts indicated the presence of mainly rutin, gallic acid, myricetin and caffeic acid. TPC of the vegetable‐fortified breads was significantly (P < 0.05) higher (5.8–7.6 mg gallic acid equivalent, GAE/g) than that of control bread (5.5 mg GAE/g). Oral administration of 100 mg dried extract/kg body weight to spontaneously hypertensive rats led to reductions (up to 42 mmHg) in systolic, diastolic and mean arterial blood pressure in comparison with 20 mmHg for the control bread.     

Effect of Various Surfactants on the Viscosity,Thermal and Electrical Conductivity of Graphene Nanoplatelets Nanofluid

International Journal of Thermophysics - The paper describes the metrological characterization of the highly stable Pt-40%Rh/Pt-6%Rh thermocouples to determine their reference function in the...     

Effective treatment of PAH contaminated Superfund site soil with the peroxy-acid process

Peroxy-organic acids are formed by the chemical reaction between organic acids and hydrogen peroxide. The peroxy-acid process was applied to two Superfund site soils provided by the U.S. Environmental Protection Agency (EPA). Initial small-scale experiments applied ratios of 3:5:7 (v/v/v) or 3:3:9 (v/v/v) hydrogen peroxide:acetic acid:deionized (DI) water solution to 5g of Superfund site soil. The experiment using 3:5:7 (v/v/v) ratio resulted in an almost complete degradation of the 14 EPA regulated polycyclic aromatic hydrocarbons (PAHs) in Bedford LT soil during a 24-h reaction period, while the 3:3:9 (v/v/v) ratio resulted in no applicable degradation in Bedford LT lot 10 soil over the same reaction period. Specific Superfund site soil characteristics (e.g., pH, total organic carbon content and particle size distribution) were found to play an important role in the availability of the PAHs and the efficiency of the transformation during the peroxy-acid process. A scaled-up experiment followed treating 150g of Bedford LT lot 10 soil with and without mixing. The scaled-up processes applied a 3:3:9 (v/v/v) solution resulting in significant decrease in PAH contamination. These findings demonstrate the peroxy-acid process as a viable option for the treatment of PAH contaminated soils. Further work is necessary in order to elucidate the mechanisms of this process.