Performances of Chitosan Grafted onto Surface of Polyacrylonitrile Functionalized through Amination Reactions

Generally, the acrylic fibers have a low chemical reactivity. Two types of treatments were used in order to increase the chemical reactivity: a pretreatment for functionalization and a treatment for polymer grafting. Each stage permitted the generation of new functional groups whose reactivity was much higher than that of the groups existing in the untreated PAN. The pretreatments were carried out with dihydroxyethyl amine (DHEA) and hydroxylamine (HA) in the presence or absence of NaOH. The functionalized samples were treated with chitosan (CS) in order to produce the grafting. The modifications resulting from the treatments were highlighted by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) analyses, the density of the new functional groups, grafting degree, energy dispersive X-ray (EDAX), yellowness index, color measurements/CIE LAB graphs. The performances referred to hygroscopicity, possibility of dyeing with acid dyestuffs (nonspecific to acrylic fibers), and excellent color fastness properties. A comparative study was performed between the results obtained through functionalization and grafting

Recycling of Nonwoven Waste Resulting from the Manufacturing Process of Hemp Fiber-Reinforced Recycled Polypropylene Composites for Upholstered Furniture Products

Waste recycling is a solution that reduces the environmental impact of waste landfilling or incineration. The aim of this paper is to investigate both the effect of incorporating recycled fibers obtained by defibrating 50/50 hemp/rPP nonwoven waste and the effect of the compatibilizer on the properties of composite materials. Composites incorporating 50% and 100% recycled fibers were treated with 2.5% and 5% maleated polypropylene (MAPP), respectively, and compared to both the untreated composites and the composite obtained by thermoforming from the nonwovens that generated the waste. The incorporation of 50% and 100% recycled fibers into composites decreased the tensile strength by 17.1–22.6%, the elongation at break by 12.4–20.1%, the flexural strength by 6.6–9%, and flexural modulus by 10.3–37%. The addition of 5% MAPP showed the greatest improvements in mechanical properties of composites containing 100% recycled fibers, as follows: 19.2% increase in tensile strength, 3.8% increase in flexural strength, and 14.8% increase in flexural modulus. Thermal analysis established that at temperatures ranging between 20 °C and 120 °C, the composites were thermally stable. SEM analysis revealed good coverage of the reinforcing fibers, and EDX analysis confirmed the presence of the compatibilizing agent in the structure of the composite material

Thermal and Mechanical Characterization of Coir Fibre–Reinforced Polypropylene Biocomposites

In recent years, the growth of environmental awareness has increased the interest in the development of biocomposites which are sustainable materials with an excellent price–performance ratio and low weight. The current study aimed to obtain and characterize the biocomposites prepared by thermoforming using coir fibres as reinforcing material and polypropylene as matrix. The biocomposites were produced with different coir fibres/polypropylene ratios and were characterized by physical–mechanical indices, thermal analysis, crystallinity, attenuated total reflection-Fourier transform infrared spectroscopy analysis (ATR-FTIR), scanning electron microscopy (SEM), and chromatic measurements. Both tensile and bending strength of biocomposites decreased when the coir fibre content increased. The melting temperature of biocomposite materials has decreased with the increase of the coir fibre loading. Regarding the thermal stability, the weight loss and degradation temperature increased with decreasing coir fibre content. The ATR-FTIR and SEM analyses underlined the modifications that took place in the structure of the biocomposites by modifying the coir fibres/matrix ratio

Thermal and Mechanical Characterization of Coir Fibre–Reinforced Polypropylene Biocomposites

In recent years, the growth of environmental awareness has increased the interest in the development of biocomposites which are sustainable materials with an excellent price–performance ratio and low weight. The current study aimed to obtain and characterize the biocomposites prepared by thermoforming using coir fibres as reinforcing material and polypropylene as matrix. The biocomposites were produced with different coir fibres/polypropylene ratios and were characterized by physical–mechanical indices, thermal analysis, crystallinity, attenuated total reflection-Fourier transform infrared spectroscopy analysis (ATR-FTIR), scanning electron microscopy (SEM), and chromatic measurements. Both tensile and bending strength of biocomposites decreased when the coir fibre content increased. The melting temperature of biocomposite materials has decreased with the increase of the coir fibre loading. Regarding the thermal stability, the weight loss and degradation temperature increased with decreasing coir fibre content. The ATR-FTIR and SEM analyses underlined the modifications that took place in the structure of the biocomposites by modifying the coir fibres/matrix ratio

Green Synthesis of Nanoparticles Containing Zinc Complexes and Their Incorporation in Topical Creams with Antimicrobial Properties

This article reports on a new way of valorizing vine leaves waste as a renewable resource of polyphenols. The nanoparticles containing zinc complexes were prepared by a green synthesis method using the aqueous extract of vine leaves as a natural source of ligands for the complexation of zinc ions. The prepared nanoparticles were characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectroscopy (EDX). Another objective of this study was to obtain a cream into which the biosynthesized nanoparticles would be incorporated. In the formulation of the new cream, we aimed to use the minimal required amounts of synthetic emulsifiers and to use natural products as co-emulsifiers or as viscosity modifiers. The organoleptic characteristics and the physicochemical properties of the obtained creams were evaluated. The experimental results confirmed that the creams wherein the nanoparticles containing zinc complexes were incorporated exhibited antimicrobial activity against the bacterial species Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Escherichia coli and the yeast Candida albicans. The values obtained for pH, viscosity and spreading diameter of the creams produced indicate that these formulations are suitable for topical applications

Tinctorial Response of Recycled PET Fibers to Chemical Modifications during Saponification and Aminolysis Reactions

In this article we show that poly­(ethylene terephthalate) (PET) fibers obtained from the recycling process of PET bottles can be chemically modified and used to create materials destined to become clothing articles. The modifications of the characteristics of PET fibers through saponification and aminolysis reactions have been studied. The work represents a comparative study of the behavior of PET virgin (of synthesis) fibers versus recycled PET fibers (from PET bottles). Comparisons have been made between the modifications which appear in physical and chemical structures, thermal stability, mechanical properties, and dyeability under the action of some reactions with NaOH, with ethylene diamine, or with their mixture at 20 °C. The FTIR, SEM, EDAX, XRD, DSC, and TGA analyses made evident the differences/similarities between the two types of studied polyester fibers. The recycled PET fibers are much less crystalline, more stable at high temperature, and easier to dye with nonspecific (anionic and cationic) dyes. After the treatment with AgNO₃, the virgin/recycled PET fibers, chemically modified (which have NH₂ groups), have antimicrobial activities due to their affinity for Ag ions. The silver presence on the treated samples can be seen even after 10 cycles of repeated home laundering. The only inconvenience of the treatments meant to modify the PET chemical structure is tenacity diminution, manifested in different ways, depending on the reagent type, concentration, and duration. However, the recycled PET fibers can be used to create materials destined to become clothing articles (by themselves or blended with synthetic/natural fibers) which can be more easily and more economically dyed in a single bath and a single stage

Preparation, characterization, and application of polysaccharide-based emulsions incorporated with lavender essential oil for skin-friendly cellulosic support

This study aimed to develop polysaccharide-based emulsions incorporated with lavender essential oil and their application on cellulosic support for patches obtaining. The lavender essential oil has been added to emulsions as an active compound mainly due to its antimicrobial properties. In this study, emulsions were used to deliver active ingredients (lavender essential oil). The chemical composition of essential oil was analyzed using gas chromatography-mass spectrometry (GC/MS). A total of seven emulsions (RiACL) were evaluated by determining rheological parameters and microbiological analysis. One of the emulsions (R7ACL) was applied to cellulosic support to obtain non-irritating textiles with controlled release of the active compound and moisturizing effects. Obtained cellulosic support was analyzed in terms of active compound controlled release, toxicity and antimicrobial testing, and skin analysis in healthy volunteers. It was found that the cellulosic supports treated with O/W emulsions are non-irritating, have softness and moisturizing effects, and can be used safely in topical applications for patches obtaining