Underwater Bonding with a Bio-Based Adhesive from Tannic Acid and Zein Protein

Here, we present several adhesive formulations made from zein protein and tannic acid that can bind to a wide range of surfaces underwater. Higher performance comes from using more tannic acid than zein, whereas dry bonding requires the opposite-more zein than tannic acid. Each adhesive works best in the environment for which it was designed and optimized. We show underwater adhesion experiments conducted on different substrates and in various water types, including seawater, saline solution, tap water, and deionized water. Surprisingly, the water type does not significantly influence performance, but the substrate type does. An additional unexpected result was the bond strength increasing over time when exposed to water, contradicting general observations with glues. Initial adhesion underwater was stronger compared to benchtop adhesion, suggesting that water helps improve adhesion. Temperature effects were examined, indicating maximum bonding at around 30 C, followed by another increase at higher temperatures. Once the adhesive was placed underwater, a protective skin formed on the surface, preventing water from immediately penetrating the rest of the material. The shape of the adhesive could be easily manipulated, and once in place, the skin could be broken to induce faster bond formation. Data indicated that underwater adhesion was predominantly induced by tannic acid, which facilitated cross-linking within the bulk material and adhesion to the substrate surfaces. The zein protein provided a less polar matrix, helping to retain the tannic acid molecules. These studies introduce new plant-based adhesives for underwater applications and contribute to creating a more sustainable environment

One-Pot Solvent-Free Synthesis of Imine-Based Epoxidized Soybean Oil Vitrimers for Sustainable Adhesives

The traditional methods for synthesizing imine based epoxidized soybean oil (ESO) vitrimers often rely on organic solvents, leading to issues such as incomplete raw material conversion, increased production costs, and environmental concerns, contradicting the principles of green and sustainable chemistry. To overcome these challenges, we propose an innovative one-pot, solvent-free approach for synthesizing imine linked ESO vitrimers via a melt reaction utilizing ESO, vanillin, and diamines. In this system, three distinct reactions can occur: phenolic hydroxy-epoxy, amino-aldehyde, and amino-epoxy. Our findings indicate that the first two reactions occur more readily and rapidly than the third, facilitating the successful synthesis of the vitrimers. We employed three different diamines to tailor the chemical structure and control properties of the ESO vitrimers; aromatic diamines produced rigid vitrimers with high strength but low ductility, while aliphatic diamines yielded flexible vitrimers with lower strength but higher ductility. All vitrimers exhibited rapid high-temperature stress relaxation and excellent reprocess ability and thermal stability. Notably, these vitrimers demonstrated impressive adhesive properties, achieving lap shear strengths between 4.0 and 6.7MPa when applied to various substrates, including wood, steel ,and aluminum . Moreover, the dynamic mine bonds enable exceptional recyclability, removability, and reusability, with recycled ESO vitrimers even surpassing their virgin counterparts in mechanical and adhesive performance, underscoring the significance of this work in advancing sustainable adhesive materials with enhanced functionality and circularity

Extraction of Cellulose from Paper Towels for Sustainable Bio-Based Polyurethane Adhesives.

The increasing consumption of paper towels generates significant waste, necessitating sustainable recycling solutions. This study investigates the extraction of cellulose from wastepaper towels and its application in bio-based polyurethane adhesives. The extraction process includes alkali treatment, bleaching, and acid hydrolysis to obtain recycled cellulose (rCL). The extracted cellulose is then used in polyurethane (PU) synthesis alongside castor oil polyol (COP) and methylene diphenyl diisocyanate (MDI), with performance compared to industrial cellulose-based polyurethane. The obtained rCL and synthesized PU adhesives have been characterized with FT-IR spectra for structural confirmation. In addition, the synthesized PU adhesives demonstrated improved mechanical and thermal properties. At room temperature, tensile testing showed that rCL-5wt.% exhibited a higher tensile strength of 7.37 MPa as compared to 6.36 MPa for CL-5 wt.%, indicating better mechanical strength of PU adhesives with rCL. Differential scanning calorimetry (DSC) analysis showed an elevated glass transition temperature (Tg) of 82.24℃ for the rCL-5wt.% and 72.26 oC for the CL-5wt.% as compared to 68.74 oC for the control sample, indicating improved thermal stability. Gel swell analysis confirmed a lower swelling and higher gel content for rCL-5wt.% as compared to CL-5wt.%, reflecting a denser, more robust polymer network structure with high crosslinking with rCL. These results suggest that recycled cellulose is a viable alternative to industrial cellulose for sustainable polymer applications. The study contributes to eco-friendly material development by promoting waste utilization and reducing reliance on petrochemical-based adhesives

Development of Bio-Based Polyurethane Adhesives: Impact of Schiff Base Crosslinkers on Mechanical and Thermal Properties

Historically, polyurethanes (PUs) are usually produced with petroleum-derived polyols like urea or phenol formaldehyde, both of which are hazardous to human health and detrimental to the ecosystem. Consequently, industries have lately shown interest in creating bio-based PUs composed of polyol derived from vegetable oil and diisocyanate. In this research, PU-based adhesives are created utilizing soybean oil polyol (SOP) and methylene diphenyl diisocyanate. To enhance the performance of synthesized PU adhesive, Schiff-based diols referred to as VB and VH have been incorporated into the system as crosslinkers, originating from butane diamine, hexane diamine, and vanillin. The successful production of PU has been validated with Fourier transform infrared spectroscopy (FT-IR) spectra. The tensile strength of adhesive samples was evaluated on oak wood specimens. In adhesive samples based on VB, VB-10wt.% exhibited the greatest tensile strength at 4400 KPa compared to all other weight percentages (wt.%), while for VH-based adhesive samples, the maximum tensile strength was recorded for VH-10wt.% at 5000 KPa. In both instances, as the wt.% of Schiff base diol rises, the tensile strength declines to 3800 KPa and 2900 KPa for VB-15wt.% and VH-15wt.% respectively. Additionally, the synthesized PU adhesive samples exhibit thermal stability, as verified by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) assessments. Furthermore, the gel content and degree of swelling tests additionally demonstrate the crosslinking efficiency of the PU adhesive materials

Improving Polyurethane Adhesives through Schiff Base Crosslinkers: A Sustainable Approach Using Soybean Oil

Historically, polyurethanes (PUs) have typically been made using petroleum-based polyols such as urea or phenol formaldehyde, both of which pose risks to human health and harm the environment. As a result, sectors have recently expressed interest in developing bio-based PUs made from polyol sourced from vegetable oil and diisocyanate. In this study, PU-based adhesives are developed using soybean oil polyol (SOP) and methylene diphenyl diisocyanate. To improve the performance of the synthesized PU adhesive, Schiff-based diols designated as VB and VH have been added to the system as crosslinkers, derived from butane diamine, hexane diamine, and vanillin. The successful creation of PU has been confirmed using Fourier transform infrared spectroscopy (FT-IR) spectra. The tensile strength of adhesive samples was tested on oak wood specimens. Among adhesive samples using VB, VB-10wt.% demonstrated the highest tensile strength at 4400 KPa when compared to all other weight percentages (wt.%). In contrast, VH-based adhesive samples recorded their maximum tensile strength for VH-10wt.% at 5000 KPa. In both cases, as the wt.% of Schiff base diol increases, the tensile strength decreases to 3800 KPa for VB-15wt.% and 2900 KPa for VH-15wt.%. Furthermore, the produced PU adhesive samples demonstrate thermal stability, as confirmed through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) evaluations. Moreover, the tests for gel content and degree of swelling further illustrate the efficiency of crosslinking in the PU adhesive materials

Fire-Resistant Coatings: Advances in Flame-Retardant Technologies, Sustainable Approaches, and Industrial Implementation

Fire-resistant coatings have emerged as crucial materials for reducing fire hazards in various industries, including construction, textiles, electronics, and aerospace. This review provides a comprehensive account of recent advances in fire-resistant coatings, emphasizing environmentally friendly and high-performance systems. Beginning with a classification of traditional halogenated and non-halogenated flame retardants (FRs), this article progresses to cover nitrogen-, phosphorus-, and hybrid-based systems. The synthesis methods, structure–property relationships, and fire suppression mechanisms are critically discussed. A particular focus is placed on bio-based and waterborne formulations that align with green chemistry principles, such as tannic acid (TA), phytic acid (PA), lignin, and deep eutectic solvents (DESs). Furthermore, the integration of nanomaterials and smart functionalities into fire-resistant coatings has demonstrated promising improvements in thermal stability, char formation, and smoke suppression. Applications in real-world contexts, ranging from wood and textiles to electronics and automotive interiors, highlight the commercial relevance of these developments. This review also addresses current challenges such as long-term durability, environmental impacts, and the standardization of performance testing. Ultimately, this article offers a roadmap for developing safer, sustainable, and multifunctional fire-resistant coatings for future materials engineering

DETECTION OF BRAIN TUMOR USING DATA SCIENCE: A SURVEY

Detection of Brain Tumor is considered as one of the most complicated processes in medical science. As brain tumor may be in various shapes and size it is very difficult to analyze it and detect it. Brain tumors grow from various types of cells and these cells can help us to know about the classification of a tumor and severity of a tumor. It may lie in different position on the brain and those positions indicate which type of cell is causing it, which is helpful information for the diagnosis later on. So, this task of brain tumor detection is difficult with the existing techniques. By observing raw images, it is very difficult to find out if it is having a Tumor or not, so any model made to make a prediction may have some limitations. This article proposes a novel method to detect brain tumors from various MRI images by deep learning method. It explains preprocessing techniques which are finalized for training and testing and observing their impact on our MRI images dataset. A dataset having different tumor shapes, sizes, textures, and locations is used to carry out experimentations, so that the good prediction can be achieved.</jats:p