PurposeThis study aims to explore sustainable strategies for enhancing the stability of natural dyes through their encapsulation within inorganic matrices, with particular emphasis on structure–stability relationships governing degradation and performance. It addresses the growing demand for eco-friendly alternatives to synthetic colorants in pigment-based industries such as textiles, packaging and cosmetics. Design/methodology/approachThe paper systematically analyzes recent developments in the encapsulation of natural dyes using inorganic carriers such as mesoporous silica, metal oxides and hybrid nanostructures. A special focus is placed on practical physics-based characterization techniques, including UV–Vis spectroscopy, thermal analysis (TGA/DSC) and structural tools (FTIR/XRD), to assess photostability, thermal resistance and release behavior, with comparative evaluation of free versus encapsulated systems. FindingsEncapsulation significantly improves the performance of natural dyes by protecting them against photodegradation, thermal decomposition and environmental leaching. Comparative studies reveal enhanced light–matter and heat–matter interaction control, leading to superior color durability and functional performance. Quantitative assessments further indicate measurable improvements in stability and reductions in ecotoxicological responses. The environmental profile of the encapsulated systems also shows reduced ecotoxicity in aqueous and soil media. Originality/valueThis work integrates materials science, applied physics and environmental chemistry to provide a multidisciplinary perspective on sustainable pigment design. It highlights how experimental physics techniques are critical for evaluating and optimizing dye–matrix interactions, providing a mechanism-oriented framework that links material structure to long-term stability and environmental performance, offering valuable insights for industrial and academic stakeholders seeking green pigment technologies.
PurposeNatural dyes and pigments make the market for the pharmaceutical, food and textile industries over various synthetic dyes due to their eco-friendly nature and impactful health benefits, as well as cosmeceutical importance. Since they are obtained from natural sources, they contribute to the upliftment of local biodiversity. Despite these advantages, natural pigments face various challenges in their colour fastness properties due to factors like photo-degradation, thermal degradation, microbial degradation, pH sensitivity, oxidation, harvesting or growing conditions and also the shortcomings of the ancient extraction methods. The purpose of this paper would be to evaluate the stability challenges of natural pigments and illustrate the various methods and approaches to improve their stability. Design/methodology/approachThis review describes the natural sources of various dyes and pigments and the common stability issues and the factors causing them. Furthermore, the present work enlightens the techniques that stabilize the colour fastness properties and improve colour stability, including co-pigmentation, complex formation, microencapsulation, addition of bio-mordant and antioxidants. Each of these techniques has been evaluated by diverse groups of scientists and applied for stabilization of natural source-based colours. FindingsAmong the techniques applied, use of nanotechnology, bio-mordanting and co-pigmentation has been found to improve the stability of pigments significantly. Future studies on the application of such methods and the commercial production of pigments may be required. Originality/valueTo the best of the authors’ knowledge, this review work focusing on techniques to improve the stability of naturally sourced pigments has been presented for the first time. It compiles and compares all the novel techniques to improve the stability of natural pigments and thus is significantly beneficial for researchers in this field.
Purpose The rising demand for environmentally friendly and sustainable dyes for textile coloring has led to a resurgence in the use of natural dyes. Nevertheless, optimizing the condition of natural dyes for application on cotton remains a challenge. This study aims to identify the effects of dyeing parameters on the properties of naturally dyed cotton. Design/methodology/approach For this purpose, a natural dye was extracted from prickly pear fruits using an aqueous method. The cotton fabric was cationized with 3-chloro-2-hydroxypropyl-trimethyl ammonium chloride to facilitate the dyeing process without using any auxiliaries. The effects of the dye bath pH, dye concentration and dyeing temperature were established experimentally. Findings It was observed that color strength (K/S) values decrease with the increase in dyeing temperature. However, good colorfastness properties, ultraviolet protection factor and K/S were obtained at low dyeing temperatures. Originality/value This research presents a sustainable natural dyeing process using a cationizing agent, achieving good fastness and K/S properties without the need for auxiliaries and at low temperatures.
PurposeOwing to increasing environmental regulations and growing concerns about the harmful byproducts generated by the textile industry, it is essential to highlight the significance of adopting sustainable materials in dyeing and printing processes that involve commercial binders. Design/methodology/approachThis study investigated the development of binders derived from renewable resources, named palm oil using as a sustainable option compared to commercial products. Four binders with varying palm oil mount of 50% (B1), 55% (B2), 60% (B3) and 65% (B4) w/w have been designed using two stages, alcoholysis and polyesterification reactions. These binders offer an economical printing solution that is compatible with both natural and synthetic fabrics, while enhancing the quality and performance of printed textiles. This approach aligns with the growing demand for sustainability in the textile industry and complies with relevant environmental regulations. Furthermore, the use of these produced binders can significantly improve the performance metrics of printed fabrics, thereby boosting customer satisfaction and enhancing market competitiveness. Alkyd resins with unique attributes and reactive characteristics are formulated and characterized solely from commercially accessible renewable resources. FindingsThe results indicated that using normal heating (NH) does not facilitate alcoholysis and polyestrification when a low quantity of oil is present, resulting in no formation of alkyd resin. In contrast, with a larger amount of oil, these processes were observed but required an extended time. Microwave irradiation (MW) enabled the reaction to complete within a few seconds, whereas conductive heating necessitated a longer duration, spanning several hours. The size of the synthesized binder particles varied with oil content, ranging from 8.26–7.31, 0.15–0.14, 0.05–0.04 and 0.40–0.20 for B1, B2, B3 and B4, respectively. While the nano size cannot be achieved when applying NH. In addition, prints created using microwave fixation demonstrated enhanced color strength, fastness characteristics and surface morphology compared to those made with traditional steaming fixation techniques. Research limitations/implicationsThere are no research limitations for this work. Binder was synthesized from a renewable resource, namely, palm oil, by applying MW to save energy, water, chemicals and time. Practical implicationsThis work has practical applications for textile coloration. It is concluded that using a different amount of palm oil by applying MW as an alternative heating source makes the process greener. Social implicationsSocially, the synthesized binder has a positive social impact on the ecosystem and global community as it does not contain any carcinogenic materials. Originality/valueThe work is original and contains value-added products for the textile printing and other confederate fields.
Purpose This study aims to clarify the relationship and establish a theoretical framework of covalent adaptive networks (CANs), which enable thermosetting epoxies to have excellent self-healing properties, facilitating their recyclability.Design/methodology/approach A scaling model was developed to describe CANs' viscoelastic behavior in thermosetting epoxies. A relaxation time function was built to characterize CAN chemical kinetics (linked to network reorganization-induced topological and viscoelastic transitions), an extended Maxwell model derived the self-healed CAN's stress-strain relationship, and model predictions were validated with experimental data.Findings The scaling model was successfully established and verified; it clarified how molecular chemical kinetics regulate CANs' self-healing performance. The model's applicability under complex conditions (e.g. extreme temperature, humidity) and to different types of thermosetting epoxies/CANs requires further exploration.Originality/value This paper provides a fundamental framework for optimizing CANs' molecular structure and viscoelastic properties, thereby enhancing thermosetting epoxies' self-healing efficiency and recyclability and promotes the development of recyclable polymer materials, aligning with green development and circular economy concepts, and reducing environmental pressure from polymer waste, which fills the research gap in relevant scaling models, offering new theoretical support for designing self-healing thermosetting epoxies.
