Effects of bleaching and functionalization of kaolinite on the mechanical and thermal properties of polyamide 6 nanocomposites

Development of shelf life-extending packaging for vitamin C syrup based on high-density polyethylene and extracted lignin argan shells

Biobased packaging is an essential parameter in the pharmaceutical industry. In the present work, bio-composites consisting of high-density polyethylene (HDPE) as a matrix and lignin recovered from argan nut shells as filler were developed to investigate their potential use as packaging materials for vitamin C drugs. The lignin was extracted via alkali and klason processes, and the effects of the extraction method as well as the lignin content on the thermal, morphological, mechanical, and rheological properties of the produced composites, as well as their application for vitamin C packaging, were investigated. Among all the prepared packaging materials, the one with desirable results in pH, color stability, hardness, and mechanical characteristics was based on alkali lignin. It achieved its highest Young's modulus enhancement, 10.12 %, at 10 % alkali lignin loading, while the highest yield strain enhancement (4.65 %) was obtained with 2 % loading. When compared to neat HDPE and HDPE/klason lignin packaging materials, vitamin C solutions packed with this composite showed a lower oxidation rate, attributed to the extremely low pH variation and high color stability of the material, which decreased the rate of vitamin C degradation. According to these findings, HDPE/alkali lignin composite is a promising vitamin C syrup packaging material.

Stable smart packaging betalain-based from red prickly pear covalently linked into cellulose/alginate blend films

Smart materials based on biomaterials have been shown growing interest by researchers. This paper investigated pH-indicator film with less leaching containing betalain molecule extracted from red prickly pear fixed in the cellulose-alginate blend as a matrix. Herein, the film was manufactured from a blend containing covalently bounded cellulose with betalain via the creation of a Fischer esterification (FE) to solve the leaching problem of dyes in contact with food. The structural, thermal, morphological optical, and mechanical properties and the pH-sensitive properties of films were examined. The FTIR and color analysis confirmed the fisher esterification. The fisher esterification led to a pH-indicator film with less leaching with significant color stability against UV light. The smart film changes colors with the pH values, where it goes from purple at a pH below 10 to yellow color at a pH above 10. All those proprieties with contact angles helped this film to be used as an intelligent film for monitoring salmon spoilage.

Functionalization of kaolinite for removal of phosphate from urban sewage

The PO4 3- widespread in urban sewages promotes eutrophication of water sources, with harmful effects to natural life and endanger human health. The removal of PO4 3- from urban sewage requires treatment at tertiary level, with high costs and low efficiency in most cases. Thus, a functionalization method for surface modification of kaolinite was proposed to improve the removal of PO4 3- from urban sewage. The kaolinite commercial did not remove PO4 3- from aqueous solution. However, the functionalized kaolinite (FK) was efficient, with a maximum removal capacity of 8.4 ± 0.1 mg PO4 3-/L, within less than 1 min of reaction. The removal of PO4 3- is associated with precipitation of pyromorphite, a mineral with low solubility (Ksp < 10-79,6). Finally, real urban sewage samples (raw and treated) were also tested for removal of PO4 3- using FK, confirming its effectiveness. The central aspects of this development are:•Functionalized kaolinite (FK), with Pb(II), for removal of PO4 3- from urban sewage was studied.•The FK was efficient for removal of up to 8.4 mg PO4 3-/L from aqueous solution, within a short reaction time.•The precipitation of pyromorphite was the mechanism responsible for removal of PO4 3- and FK efficiency have been confirmed for real urban sewage samples.