In the present work, the use of a commercial ionic liquid as a convenient solvent medium for graphite exfoliation in mild and easy conditions without any chemical modification is presented. To confirm the presence of few layer graphene, its dispersion, which exhibits Tyndall effect, was characterized by Raman and UV spectroscopies, and atomic force and field emission electron microscopies. It is noteworthy that, by gravimetric analysis, a graphene concentration as high as 5.33 mg ml−1 was determined, which is the highest value reported so far in any solvent.
10 January 2011 in Journal of Polymer Science Part A: Polymer Chemistry
This work introduces two datasets: FTIR-Plastics-C4 (Fourier Transform Infrared Spectroscopy, in plastics, at a wavenumber spectral resolution of 4 cm⁻¹) and FTIR-Plastics-C8 (Fourier Transform Infrared Spectroscopy, in plastics, at a wavenumber spectral resolution of 8 cm⁻¹), each comprising 3,000 spectra corresponding to the most used synthetic polymers worldwide. The main contribution of this work lies in the selection and FTIR characterization of the six polymers commonly used in everyday life and industry, namely Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low-Density Polyethylene (LDPE), Polypropylene (PP), and Polystyrene (PS). FTIR-Plastics-C4 consists of 3,000 spectra obtained with a configuration of 32 scans and a resolution of 4 cm⁻¹, covering a range from 4000 to 400 cm⁻¹. The FTIR-Plastics-C8 dataset also contains 3,000 spectra obtained with 32 scans and a resolution of 8 cm⁻¹ within the same range. A cleaning stage was applied to the FTIR-Plastics datasets, removing the header containing 19 lines and a footer with 34 lines from the original file. Additionally, a standardization process assigns 15 lines in the files to highlight information regarding the equipment used (based on the information provided by a Jasco spectrophotometer, model FT/IR-6700 PRO 4x, used for polymer characterization). The final dataset is in tabular .csv file format. The dataset is available on an open repository, and its application was designed to identify microplastics extracted from the environment and enable comparisons between commercial polymers.
1 October 2010 in Journal of Polymer Science Part A: Polymer Chemistry
Antihypertensive peptide fraction from whey protein hydrolysate <3 kDa (measured as angiotensin-converting enzyme (ACE) activity %) was isolated and encapsulated into three composite materials: alginate–collagen, alginate Arabic gum, and alginate–gelatin. The release behavior of peptide fraction from capsules was analyzed according to the encapsulation material efficiency, the characteristics of the capsules, and the released antihypertensive peptides during gastrointestinal digestion. The highest encapsulation efficiency was found in capsules of alginate Arabic gum (95%). In this case, the released peptides incremented their ACE activity (85%) after the digestion process, with respect to the initial ACE activity (74%). Whey antihypertensive fraction revealed five peptide sequences; however, other amino acid sequences were released from digested capsules. Protein databases confirmed some antihypertensive sequences indicating the peptides content from β-Lg and α-La. Consequently, new peptides could be revealed from whey antihypertensive fraction.