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Levulinic acid, which can be obtained from biomass, has sparked great interest as a biologically-based chemical building block with wide versatility and potential. Its esterification with alcohols of different chain lengths is a promising valorization process for obtaining esters with various applications in the areas of biofuels/biolubricants, food and cosmetics, among others. In this work, the enzymatic esterification of levulinic acid and 1-octanol using a biocatalyst derived from Araujia sericifera latex was studied in systems with and without solvent. The influence of the molar ratio between alcohol and acid (ranging from 2:1–1:9), the biocatalyst loading (between 7.5 % and 17.5 % relative to the acid), the volume of n -heptane used as reaction solvent (from 0 to 4 ml), and the reaction time (6 hours) were investigated. The activity and stability of the biocatalyst in successive uses were also analyzed. A conversion of 49 % was achieved when the reaction was carried out in a solvent-free system, using an alcohol/acid molar ratio of 1:7 and after 5 h of reaction. On the other hand, the conversion was 65.1 % when the reaction was conducted in a system containing 1 ml of n -heptane as solvent, an alcohol/acid molar ratio of 1:8, and 5 h of reaction. In both cases, a temperature as low as 30 °C and an agitation speed of 300 RPM were used. • Enzymatic route for levulinic acid esterification using biocatalyst. • Araujia sericifera latex-derived biocatalyst demonstrates high activity. • Achieved 65.1 % conversion of levulinic acid in the synthesis of octyl levulinate. • Solvent-free and n-heptane solvent systems investigated. • Studied reaction parameters for optimal conversion. [ABSTRACT FROM AUTHOR]

The papermaking, packaging, and printing industry are actively seeking sustainable material alternatives to address growing concerns about environmental consciousness and finite resources. Synthetic latex, a frequently utilized binder in paper coating formulations, present difficulties due to their dependence on fossil fuel resources and their reduced recyclability in comparison to eco‐friendly sustainable products. In this study, synthetic latex was replaced with a starch‐based nanoparticle (starch NP) binder at a 1:1 ratio in a coating formulation. Printing trials to assess colorimetric characteristics was made using electrophotography (EP) printing, given the current upward trajectory and expansion of EP technology into the label, packaging, and folding carton sectors. The in‐depth investigations reveal that incorporating starch NP binder result in improved optical, color, and dot characteristics. Moreover, it maintains consistent and comparable coefficients of friction. Partial replacement of synthetic latex with the starch NP binder yields significant enhancements in surface roughness and text quality. Importantly, the starch NP binder not only improves the dielectric relaxation properties of the paper and enhances toner transfer but also accelerates the distribution of the electrical field compared to synthetic latex, optimizing toner transfer and thereby enhancing color gamut volume. The study demonstrates that employing the starch NP binder leads to substantial improvements in colorimetric performance without any drawbacks in EP printing, making it highly advantageous to replace 50% of the synthetic binder. [ABSTRACT FROM AUTHOR]

Factors that mediate insect herbivore sabotaging behaviour of host plant latex defences remain under debate. The most prominent hypothesis suggests that the anatomy of the host plant's laticifers determines trenching or vein‐cutting behaviour, but there are inconsistencies in the literature. In addition to latex, other plant defences have been shown to affect plant natural enemies, but experimental studies comparing the effects of multiple defences on herbivore performance and behaviour are scarce. In this study, we investigated the anatomy of the laticifers of Calotropis procera (Aiton) W.T. Aiton (Apocynaceae), an exotic milkweed of southeastern Brazil, as well as the sabotaging behaviour of larvae of southern monarch, Danaus erippus (Cramer), and queen butterfly, Danaus gilippus (Cramer) (Lepidoptera: Nymphalidae) on this host plant. We also reviewed the sabotaging behaviour of larvae reared on the native milkweed Asclepias curassavica L. (Apocynaceae) from previous studies, as well as the description of the anatomy of its laticifers. As we found no correspondence between sabotaging behaviour of southern monarchs and queens and the anatomy of the host plants' laticifers, we tested whether structural defences of C. procera leaves (latex, waxes and trichomes) affected sabotaging behaviour and larval performance of southern monarch larvae. The structural barriers of this well‐defended host affected larvae in different ways: Southern monarchs developed more slowly on control leaves than on leaves from which wax had been removed, and only latex removal reduced the frequency of sabotaging behaviour. Regardless of the defence removal treatment, frequencies of trenching behaviour decreased and vein‐cutting behaviour increased as larvae developed. Overall, our results show that several factors in addition to the anatomy of laticifers affect sabotaging behaviour of southern monarchs and queens, including larval ontogeny, danaine species and latex outflow. This evidence suggests a behavioural plasticity in the sabotaging behaviour of larvae of both southern monarchs and queens. [ABSTRACT FROM AUTHOR]

Research into sustainable packaging materials has gained increasing importance due to the pressing environmental concerns related to plastic waste. The present study focused on developing a sustainable paper coating based on modified natural rubber (NR) latex filled with gelatin (GT). The graft copolymer latex of NR and poly(vinylbenzyl chloride) bearing quaternary ammonium groups, abbreviated as NR-g-QPVBC, was first synthesized. GT was then incorporated into the latex, and the combination of these materials resulted in a heat-sealable film with good tensile properties and a water barrier. The ionic crosslinking of the latex film was achieved by the reaction with ethylenediaminetetraacetic acid (EDTA). Heat-sealing studies of the NR-g-QPVBC latex film filled with GT (NR-g-QPVBC/GT) revealed its heat-sealability at 160 °C. Scanning electron microscope (SEM) analysis further confirmed the diffusion of the chains across the interface during heat sealing. Dip coating was a method for depositing latex film on kraft paper. The paper coated with the NR-g-QPVBC/GT latex showed a significant increase in dry and wet-tensile strength compared to the uncoated paper. The sealing process was optimized to achieve a heat-seal strength of 755.31 N/m at a dwell time of 3 s and a temperature of 160 °C. The research's practical application was demonstrated by transforming the coated paper into various heat-sealable bags using a handheld bag sealer. [ABSTRACT FROM AUTHOR]

In this study, the bulk modification method via incorporating two different types of waterproof admixtures was adopted to make natural hydraulic lime-based mortars more durable. The influence of two admixtures and their dosages on the hydration, physical, mechanical, and aggressive environment resistance properties were evaluated. The correlations between pore and water absorption characteristics, between hydration, pore characteristics, and mechanical strength were interpreted. Results showed that two waterproof admixtures changed the microscopic reaction between different components as well as internal structure of NHL-based mortar. Introduction of silane impregnant improved the workability of natural hydraulic lime-based mortars, and the appropriate dosage of silane impregnant facilitated hydration and improved mechanical strength at 28 and 90 days. Silane impregnant modified mortars were no more hydrophilic, acid resistance was improved while water absorption characteristics were not obviously improved even resulting in degraded freeze-thaw cycle resistance. Introduction of silicon-acrylic latex deteriorated the workability and retarded hydration of natural hydraulic lime-based mortars, regardless of dosage, leading to the degradation of mechanical strength. However, water absorption characteristics and freeze-thaw cycle and acid resistance can get a noticeable improvement when appropriate dosage was adopted. [ABSTRACT FROM AUTHOR]

Background: Lactoferrin (LF) in human milk has various biological properties and contributes to the prevention of preterm birth complications. Enzyme-linked immunosorbent assay (ELISA) is one of the most commonly used methods to measure LF in human milk, but this method is time-consuming and laborious. In Japanese human milk banks, the concentration of LF in donor human milk (DHM) is measured routinely. Here, we reported a rapid, simple, and accurate method for determining LF in human milk using a new reagent based on a latex agglutination assay. Methods: We obtained 208 human milk pools from 148 mothers, and samples were collected before and after Holder pasteurization. Milk samples were diluted 100- or 200-fold and LF concentrations were measured by a latex agglutination assay using an automated analyzer. The reagent was validated in terms of repeatability, linearity, detection limit, recovery, and comparison with ELISA. Results: The coefficient of variation (CV) for intra-assay precision ranged from 0.6 to 5.0% in human milk with high, medium, and low LF concentrations. The linearity was also tested by serial sample dilution and was confirmed up to 16 µg/mL with a detection limit of 0.2 µg/mL. The recovery rates in a spiked recovery test were ranged from 90 to 120% at high, medium, and low concentrations of LF. Furthermore, a strong correlation was observed between LF levels determined by the latex agglutination assay and ELISA (r = 0.978, p < 0.001, n = 255). The regression equation was y = 0.991x + 0.545 (r2 = 0.974, p < 0.001). Compared with ELISA, the latex agglutination assay reduces the measurement time by 160 min and the cost by 55%. Conclusions: The latex agglutination assay used to determine LF in human milk is rapid, simple, and accurate enough to be used routinely. Its use may contribute to the quick and easy provision of appropriate DHM to preterm infants. [ABSTRACT FROM AUTHOR]

Protective clothing standards, such as test methods published by ASTM International, play an integral role in ensuring the performance of personal protective equipment. The standard tests are not without limitations and are periodically reviewed and often updated. Some tests may not be reflective of in-use conditions. A new test cell was designed using sanitary fixtures to evaluate the effect of glove stretch on barrier performance using fluorescein solution as the challenge agent for enhanced visualization and fluorometer detection. Domed-shaped and flat screens were developed to permit and limit glove stretch within the test cell. The barrier performance of glove swatches was evaluated for both stretched and unstretched states. Latex, nitrile, and vinyl glove models of various thicknesses were evaluated. The tests were conducted following pressure and time parameters specified in ASTM F903, ASTM F1670, and ASTM F1671. Fluorescein solution movement, which may occur through penetration, was measured using a fluorometer. Glove stretch caused a reduction in glove thickness ranging from 16% to 40%. Overall, 21 sample failures were found (16.7%; n = 126) regardless of test condition. Nitrile gloves provided better barrier efficacy with the lowest failure rates (2.38%; 1 failure out of 42) compared to latex (19.4%; 7 failures out of 36) and vinyl gloves (27.1%; 13 failures out of 48). Differences in failure rates between stretched and unstretched gloves were insignificant; however, the latex material showed a 2.5 times increase in failures when stretched compared to unstretched. The new test apparatus was able to differentiate between the barrier performance of different glove materials. The use of a domed screen allowed the gloves to stretch, a condition that better represents the state of gloves when in use. Analysis of samples collected from the glove surface opposite to the exposure may provide a way to assess chemical permeation in addition to penetration. [ABSTRACT FROM AUTHOR]

Ion chromatography is the anion analysis benchmark. A miniature form, Open Tubular Ion Chromatography (OTIC), has attractive attributes for efficient ion separations. Here, we fabricate and characterize high‐density polyethylene (HDPE) open tubular anion exchange columns (OTCs). We attach positively charged latex particles onto negatively charged capillary surfaces. For efficient OTIC, column diameters need to be < ∼20 µm; functionalizing the bore is challenging. Methods to introduce acid groups to an HDPE capillary bore, e.g., sulfonation using chlorosulfonic or sulfuric acid solutions, with or without grafting of an aromatic ring through photo‐ or chemical grafting first, are explored. Following quaternary ammonium latex attachment, the ion exchange capacity and separating abilities of each OTC were measured as an index of OTC performance. Gradual loss of capacity was observed for many of these; high‐resolution mass spectrometry confirmed the leaching of detached oxidized/sulfonated oligomeric fragments and consequent poisoning of the latex sites. Ways to ameliorate this and/or to rejuvenate the columns are also described. [ABSTRACT FROM AUTHOR]

The development of new materials for antifreezing and anti‐icing applications is a big challenge in industry and academic area. Inspired by the antifreeze proteins, latex particles with superhydrophilic zwitterionic shells and superhydrophobic cores are synthesized by reversible addition‐fragmentation chain transfer emulsion polymerization, and the applications of the latex particles in antifreezing and anti‐icing applications are investigated. In antifreezing study, the critical aggregate temperature (CAT) of the latex particles decreases, and the separation of the melting and freezing temperature of ice increases with the particle concentration. Enzyme molecules can be cryopreserved in the particle solution, and their bioactivities are well maintained. Latex particles are casted into latex films with dynamic surfaces. Anti‐icing performances, including antifrosting properties, freezing delay time, and ice adhesion strengths, are studied; and the water‐treated latex films present stronger anti‐icing properties than other films, due to the synergistic effects of the superhydrophilic and superhydrophobic components. In addition, latex particles with zwitterionic shells and poly(n‐butyl methacrylate) cores, and latex particles with small molecular surfactant on the surfaces are synthesized. The antifreezing performances of the latex particles and anti‐icing properties of the latex films are compared. [ABSTRACT FROM AUTHOR]

This study introduces a tunable acoustic tweezer system designed for precise three-dimensional particle trapping and manipulation. The system utilizes a dual-liquid-layer acoustic lens, which enables the dynamic control of the focal length through the adjustable curvature of a latex membrane. This tunability is essential for generating the acoustic forces necessary for effective manipulation of particles, particularly along the direction of acoustic wave propagation ( z -axis). Experiments conducted with spherical particles as small as 1.5 mm in diameter demonstrated the system's capability for stable trapping and manipulation. Performance was rigorously evaluated through both z -axis and 3D manipulation tests. In the z-axis experiments, the system achieved a manipulation range of 33.4–53.4 mm, with a root-mean-square error and standard deviation of 0.044 ± 0.045 mm, which highlights its precision. Further, the 3D manipulation experiments showed that particles could be accurately guided along complex paths, including multilayer rectangular and helical trajectories, with minimal deviation. A visual feedback-based particle navigation system significantly enhanced positional accuracy, reducing errors relative to open-loop control. These results confirm that the tunable acoustic tweezer system is a robust tool for applications requiring precise control of particles with diameter of 1.5 mm in three-dimensional environments. Considering its ability to dynamically adjust the focal point and maintain stable trapping, this system is well suited for tasks demanding high precision, such as targeted particle delivery and other applications involving advanced material manipulation. [ABSTRACT FROM AUTHOR]

In the search for packaging that causes lower environmental damage, paper has been widely targeted to increase its use in the packaging industries. Still, the water and oil barrier characteristics need to be improved. To correct such deficiencies, different formulations of natural rubber incorporated with cellulose micro/nanofibrils, and carnauba wax were evaluated as alternative coatings of renewable and biodegradable origin on kraftliner and paperboard in the oil and water barrier properties at different grammage (5, 10 and 15 g/m2). The contact angle showed the hydrophobic characteristics of coated papers with angle values of 105° for rubber coatings with micro/nanofibrils and the stability of the water drop with the evaluation of wettability with values close to zero (0.01°/s). The results of Cobb 120 confirmed the hydrophobicity of the coated papers with values close to zero and close to those found by the polyacrylate varnish and the reduction of water vapor permeation by up to 65%. In addition to decreased affinity for water, the papers were also resistant to oil, reaching the maximum resistance value (kit-oil n° 12). Because of these results, natural rubber presents itself as a possible substitute for synthetic materials for covering papers and, together with the micro/nanofibrils of cellulose and carnauba wax, can correct the barrier deficiencies of the papers. [ABSTRACT FROM AUTHOR]

Taraxacum kok-saghyz Rodin (TKS) is a recognized alternative source of natural rubber comparable to the rubber tree. The geranylgeranyl pyrophosphate synthase (GGPS) catalyzed the synthesis of geranylgeranyl pyrophosphate (GGPP), which is an important enzyme in the secondary metabolism pathway. In this study, we present the first analysis of the GGPS gene family in TKS, where a total of seven TkGGPS family members were identified. Their core motifs, conserved structural domains, gene structures, and cis-acting elements were described. In addition, two phylogenetic trees were constructed based on the Neighbor-Joining and Maximum-Likelihood methods, and the TkGGPSs were highly conserved and exhibited good collinearity with the other species. Transcriptome data showed that seven TkGGPS gene members were expressed in all the 12 tissues measured, and TkGGPS1, TkGGPS3, and TkGGPS6 were highly expressed in latex, suggesting that they may be associated with natural rubber synthesis. Meanwhile, quantitative real-time PCR (qRT-PCR) showed that the expression levels of the TkGGPS genes were regulated by the ethylene and methyl jasmonate (MeJA) pathways. Subcellular localization results indicated that all the TkGGPS proteins were also located in chloroplasts involved in photosynthesis in plants. This study will provide valuable insights into the selection of candidate genes for molecular breeding and natural rubber biosynthesis in TKS. [ABSTRACT FROM AUTHOR]

This article outlines an innovative procedure to improve the accessibility of Mathematics for secondary school students with visual impairments. Using LATEX, a widely used typesetting system, a transformative approach is developed that converts traditional mathematical content into three accessible formats: PDF, MathJax and LAMBDA. Central to this system is the integration of alternative text, which offers full descriptions of images and mathematical formulae and promotes a richer understanding of its content. The broader implications of this project include the introduction of novel teaching models for educators, enhanced accessibility of Mathematics programmes, and the potential to encourage the enrolment of visually impaired students in science degree courses. Ultimately, this work contributes to the creation of the conditions for the development of an inclusive and barrier-free learning environment in Mathematics education. [ABSTRACT FROM AUTHOR]

In this paper, green composite films comprising natural rubber (NR), cellulose (CE), and chitosan (CS) were successfully fabricated through a simple, facile, cost-effective method in order to improve mechanical, chemical, and antimicrobial properties of NR composite films. Chitosan with a low molecular weight of 30,000–50,000 g/mol (CS-L) and a medium molecular weight of 300,000–500,000 g/mol (CS-M) was used for the fabrication. The composite films were prepared via a latex aqueous microdispersion method with different weight ratios of NR:CE:CS-L/CS-M. Fourier transform infrared spectroscopy (FTIR) results demonstrated strong interactions of hydrogen bonds between CE and CS-L/CS-M in the composite films. The tensile strength and the modulus of the composite films in dried form were found to significantly increase with the reinforcement of CE and CS-L/CS-M. The maximum tensile strength (13.8 MPa) and Young's modulus (12.7 MPa) were obtained from the composite films reinforced with CE at 10 wt.% and CS-L at 10 wt.%. The high elongation of 500–526% was obtained from the composite films reinforced with CE at 10 wt.% and CS (CS-L or CS-M) at 5.0 wt.%. The modification could also significantly promote antimicrobial activities and chemical resistance against non-polar solvents in the composite films. The NR composite films have potential uses as flexible films for sustainable green packaging. [ABSTRACT FROM AUTHOR]

Colloidal polymers, and in particular aqueous polymer dispersions, are widely used in commercial applications such as coatings and adhesives. Historically, the solvent resistance and mechanical properties of these systems have been improved by covalently crosslinking the polymer chains after drying. More recently, work has been directed toward replacing this covalent crosslinking, which typically involves highly reactive functional groups, by physical crosslinking through the use of supramolecular interactions. While conceptually similar to the use of covalent crosslinking, physical crosslinking has a unique influence on the rheology of the polymer, which leads to substantial differences in the development of mechanical strength during drying, as well as the mechanical properties of the final polymer film. In this perspective, the advantages and challenges of this approach are outlined, and an outlook for future research in this direction is provided. [ABSTRACT FROM AUTHOR]

Background: Although natural rubber latex remains dominant as the primary manufacturing material for male condoms synthetic materials first introduced in the early 1990s address many of the limitations of latex including the risk of allergies. Polyurethane elastomers allow condoms to be made significantly thinner to provide greater sensitivity and encourage greater use of condoms for contraception and STI prophylaxis. The primary objective of this Study was to evaluate the breakage, slippage and acceptability of two ultra-thin polyurethane condoms against a thin control latex male condom, designated latex C, in a randomized, cross over, masked, non-inferiority study. The condom designated Polyurethane A was designed for markets where 52/53 mm wide latex condoms are preferred whereas the condom designated Polyurethane B was designed for markets where the smaller 49 mm wide latex condom is preferred. Methods: The Study was designed to meet the requirements specified in ISO 29943–1: 2017 and FDA guidelines for clinical studies on synthetic condoms. It was conducted by two Essential Access Health centres, one in Northern California and the other in Southern California. Sexually active heterosexual couples (300) aged between 18 and 45 years were recruited to use three sets of five condoms in a block randomized order, recording breakage, slippage and acceptability after each use. A total of 252 couples contributed 2405 evaluable condom uses per protocol for the Condom A versus Latex C comparison (1193 Polyurethane A plus 1212 Latex C), and 247 couples provided 2335 evaluable condom uses per protocol for the Condom B versus Latex C comparison (1142 Polyurethane B plus 1193 Latex C). Only condoms used for vaginal intercourse were included in the analysis. Findings: Although the total failure rates (breakage and slippage) for the polyurethane condoms were higher than for the control Latex C condom, all condoms performed extremely well with low failure rates compared to similar condom studies. Condom Polyurethane A met the noninferiority requirements specified in ISO 23409:2011 relative to Latex C, the control NR latex condom, in the full Study population. While condom Polyurethane B did not meet the noninferiority requirement for the full Study population, it did meet the noninferiority requirement when analysis was restricted to the intended population (men with penis lengths ≤ 170 mm). Trial registration The Study is registered with ClinicalTrials.gov, NCT04622306, Protocol Reference SAGCS 2, initial release date 11/02/2020. [ABSTRACT FROM AUTHOR]

Transport of monomer from droplets to growing latex particles in emulsion polymerization in general is assumed to proceed via diffusion through the aqueous phase. Especially in miniemulsion polymerizations the direct transfer of very hydrophobic species from droplet to droplet is assumed to also proceed via collisions. Amongst the hydrophobic species where this is shown to play a role are monomers, initiators, inhibitors and (catalytic) chain transfer agents. It is well known that the reactor geometry and the stirring speed can have a profound effect on emulsion polymerizations. The 1972 paper of Nomura on the effect of stirring on emulsion polymerization is cited more than 100 times and until today keeps scientists intrigued. Diffusion limitations of monomer going from the droplet into the aqueous phase can occur for very hydrophobic monomers. The alternative route of transport via collisions is often not considered. In this perspective, paper will discuss the evidence for collision based transfer in miniemulsion polymerization and also consider whether collision based monomer transport can play a role in regular emulsion polymerizations. [ABSTRACT FROM AUTHOR]

The use of polymer latexes for high‐performance coatings is challenging as the properties required to allow for film formation at reasonable temperatures tend to result in films with relatively poor mechanical properties. In this review, routes to overcome this so‐called film‐formation dilemma are discussed. First, the use of coalescing agents, focusing in particular on more recent approaches to minimize the use of volatile organic compounds (VOCs), is reviewed. Subsequently, approaches that utilize hybrid latexes are considered. This includes the use of high/low Tg latex blends, nanocomposites that include a second, non‐polymeric phase, and multiphase latexes. Finally, the use of crosslinking technologies is considered, with a focus on necessary developments to reduce environmental impact. The review concludes with a summary and a discussion of possible future directions for research. [ABSTRACT FROM AUTHOR]

The Latex Diagnosis (LD) is performed through the determination of dry rubber (DRC), sucrose (Suc), inorganic phosphorus (Pi) and thiol (RSH) contents. It is carried out through the colorimetric method using a single cuvette spectrophotometer, which is time-consuming and requires a high volume of chemicals. It also needs to be executed as soon as the samples are collected so that limits the adoption of LD. The adaptation of the protocol to a multiplate reader and suitable conservation aimed to overcome the limitations. The experiments were carried out at the Indonesian Rubber Research Institute, Sembawa, Palembang, and Research Center for Biotechnology, Universitas Gadjah Mada, Yogyakarta. Various combinations of solution volumes, adapted from standard protocol, were tested. The closest slope of the standard curve to control was then applied to 7 randomly selected trees. The result showed that for Suc, the composition of 10 µL samples, 30 µL of 2.5 % TCA and 210 µL anthrone reagent was suitable for determination using a multiplate reader. The combination of 40 µL of sample, 85 µL of 2.5 % TCA and 125 µL mL FeSO4 solution was suitable for Pi determination, while 100 µL samples, 5 µL DNTB and 100 µL Tris is recommended for RSH. The measurement using a multiplate reader resulted in comparable contents (average deviations were 1.83, 2.69 and 3.51 % for Suc, Pi, and RSH, respectively), lower time and chemicals consumptions, and a larger number of sample handling compared to single cuvette method. This study also tested the effect of freeze-drying for sample conservation. The result indicated that freezedrying was able to maintain the Pi level (deviation 0.93 %). However, it increased Suc (deviation 19.43 %) and decreased ascorbate (AsA) significantly (deviation 43.60 %); therefore, freeze-drying might not be suitable for conserving serum samples in the LD method. [ABSTRACT FROM AUTHOR]

Latex of C. gigantea was used to synthesize zinc oxide nanoparticles (ZnO NPs) by the green chemistry approach. The crystalline size, shape, and purity of as-synthesized ZnO NPs were characterized through scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy techniques. Crystalline, spherical ZnO NPs with an average size of 21.8 nm were formed. In addition, the biological properties of the ZnO NPs, such as antioxidant and antibacterial activity, were evaluated by 2,2-diphenyl-1-picrylhydrazyl assay and the agar well-diffusion method. The highest free radical scavenging activities of 83.11 ± 1.89 % were observed at a concentration of 350 μg/mL of C. gigantea latex-mediated ZnO NPs. The latex in the C. gigantea latex-mediated ZnO NPs inhibited the growth of pathogenic bacteria. The maximum zone of inhibition was found in P. aeruginosa and S. aureus. C. gigantea latex-mediated ZnO NPs have significant biocompatibility and broad-spectrum antibacterial properties against wound-causing bacteria and, therefore, can be suggested for use in the formulation of novel creams or gels for healing applications. [ABSTRACT FROM AUTHOR]

The current research investigation aimed to screen the bioactive compounds in the latex of Calotropis gigantea L. and evaluate its antibacterial and antioxidant properties towards clinical applications. The chemical moiety and volatile compounds of the latex of C. gigantea were detected by UV–Vis spectroscopy, FT-IR, and GC–MS analysis. The antibacterial activity was assessed using wound-inducing pathogens by well diffusion method. In addition, the antioxidant properties were determined through DPPH, ABTS, and FRAP methods. The functional groups of O–H stretch, diketonic bonds, C–O, C–N, O–C bonds, and consecutive C–H bonds were observed in the latex of C. gigantea. The major bioactive compounds were 5H-3,5a-Epoxynaphth[2,1-c]oxepin, Cholesta-5-en-3-ol, 24-propylidene-, dodecane, Lup-20(29)-Ene-3,28-Diol, (3.Beta)-, Veridiflorol, and Lanosta-8,24-dien-3-ol, acetatate, (3.beta.). Oxazole derivatives were found in the latex of C. gigantea, proved by GC–MS analysis. The aqueous-mixed latex exhibited maximum antioxidant activity as compared to methanol-mixed latex. Aqueous-mixed latex and methanol-mixed latex inhibited the growth of K. pneumoniae, P. mirabilis, S. pyogenes, Micrococcus spp., S. aureus, P. aeruginosa, and E. coli. The present study clearly reveals that latex of C. gigantea has rich bioactive compounds with significant biological activities, and can be employed to produce a novel herbal formulation against wound-inducing pathogens. [ABSTRACT FROM AUTHOR]

For polyacrylate latex pressure-sensitive adhesives (PSAs), high peel strength is of crucial significance. It is not only a key factor for ensuring the long-lasting and effective adhesive force of polyacrylate latex PSAs but also can significantly expand their application scope in many vital fields, such as packaging, electronics, and medical high-performance composite materials. High peel strength can guarantee that the products maintain stable and reliable adhesive performance under complex and variable environmental conditions. However, at present, the peel strength capacity of polyacrylate latex PSAs is conspicuously insufficient, making it difficult to fully meet the urgent market demand for high peel strength, and severely restricting their application in many cutting-edge fields. Therefore, based on previous experimental studies, and deeply inspired by the adhesion mechanism of natural marine mussels, in this study, a traditional polyacrylate latex PSA was ingeniously graft-modified with 3,4-dihydroxybenzaldehyde (DHBA) through the method of monomer-starved seeded semi-continuous emulsion polymerization, successfully synthesizing novel high-peel-strength polyacrylate latex pressure-sensitive adhesives (HPSAs) with outstanding strong adhesion properties, and the influence of DHBA content on the properties of the HPSAs was comprehensively studied. The research results indicated that the properties of the modified HPSAs were comprehensively enhanced. Regarding the water resistance of the adhesive film, the minimum water absorption rate was 4.33%. In terms of the heat resistance of the adhesive tape, it could withstand heat at 90 °C for 1 h without leaving residue upon tape peeling. Notably, the adhesive properties were significantly improved, and when the DHBA content reached 4.0%, the loop tack and 180° peel strength of HPSA4 significantly increased to 5.75 N and 825.4 gf/25 mm, respectively, which were 2.5 times and 2 times those of the unmodified PSA, respectively. Such superior adhesive performance of HPSAs, on the one hand, should be attributed to the introduction of the bonding functional monomer DHBA with a rich polyphenol structure; on the other hand, the acetal structure formed by the grafting reaction of DHBA with the PSA effectively enhanced the spatial network and crosslink density of the HPSAs. In summary, in this study, the natural biological adhesion phenomenon was ingeniously utilized to increase the peel strength of pressure-sensitive adhesives, providing a highly forward-looking and feasible direct strategy for the development of environmentally friendly polyacrylate latex pressure-sensitive adhesives. [ABSTRACT FROM AUTHOR]

This study explores the potential for recycling natural rubber (NR) latex waste from balloon production through the devulcanization and revulcanization processes. The mechanical devulcanization of colored latex balloon waste was conducted, followed by revulcanization using a sulfur-based system. The reclaimed rubber's properties, including crosslink density, tensile strength, and abrasion resistance, were compared with those of virgin NR. The results demonstrate that the reclaimed rubber maintains a crosslink density close to that of virgin NR. Hardness and abrasion resistance were comparable, indicating successful material recovery. Structural analyses, including FTIR and SEM microscopy, revealed that the devulcanization process effectively allowed for successful revulcanization. This study concludes that NR latex waste can be effectively recycled and reused in rubber composite formulations, offering a sustainable approach to waste management in the rubber industry and contributing to developing eco-friendly materials. In the context of this research, integrating advanced chemical and physical methods, such as solubility parameter calculations and enhanced devulcanization techniques, could further optimize the devulcanization process. These methods quantitatively enhance the efficiency of material recovery, offering a path to more sustainable recycling practices. The findings suggest that combining such advanced methodologies could significantly improve recycled NR latex's overall performance and applicability in industrial applications. [ABSTRACT FROM AUTHOR]

The current research investigation aimed to screen the bioactive compounds in the latex of Calotropis gigantea L. and evaluate its antibacterial and antioxidant properties towards clinical applications. The chemical moiety and volatile compounds of the latex of C. gigantea were detected by UV–Vis spectroscopy, FT-IR, and GC–MS analysis. The antibacterial activity was assessed using wound-inducing pathogens by well diffusion method. In addition, the antioxidant properties were determined through DPPH, ABTS, and FRAP methods. The functional groups of O–H stretch, diketonic bonds, C–O, C–N, O–C bonds, and consecutive C–H bonds were observed in the latex of C. gigantea. The major bioactive compounds were 5H-3,5a-Epoxynaphth[2,1-c]oxepin, Cholesta-5-en-3-ol, 24-propylidene-, dodecane, Lup-20(29)-Ene-3,28-Diol, (3.Beta)-, Veridiflorol, and Lanosta-8,24-dien-3-ol, acetatate, (3.beta.). Oxazole derivatives were found in the latex of C. gigantea, proved by GC–MS analysis. The aqueous-mixed latex exhibited maximum antioxidant activity as compared to methanol-mixed latex. Aqueous-mixed latex and methanol-mixed latex inhibited the growth of K. pneumoniae, P. mirabilis, S. pyogenes, Micrococcus spp., S. aureus, P. aeruginosa, and E. coli. The present study clearly reveals that latex of C. gigantea has rich bioactive compounds with significant biological activities, and can be employed to produce a novel herbal formulation against wound-inducing pathogens.

Latex of C. gigantea was used to synthesize zinc oxide nanoparticles (ZnO NPs) by the green chemistry approach. The crystalline size, shape, and purity of as-synthesized ZnO NPs were characterized through scanning electron microscopy with energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction analysis, and Fourier-transform infrared spectroscopy techniques. Crystalline, spherical ZnO NPs with an average size of 21.8 nm were formed. In addition, the biological properties of the ZnO NPs, such as antioxidant and antibacterial activity, were evaluated by 2,2-diphenyl-1-picrylhydrazyl assay and the agar well-diffusion method. The highest free radical scavenging activities of 83.11 ± 1.89 % were observed at a concentration of 350 μg/mL of C. gigantea latex-mediated ZnO NPs. The latex in the C. gigantea latex-mediated ZnO NPs inhibited the growth of pathogenic bacteria. The maximum zone of inhibition was found in P. aeruginosa and S. aureus. C. gigantea latex-mediated ZnO NPs have significant biocompatibility and broad-spectrum antibacterial properties against wound-causing bacteria and, therefore, can be suggested for use in the formulation of novel creams or gels for healing applications.

Recent global market disruptions, including the COVID-19 crisis, inflation, and oil crises, have highlighted the need for industries to reduce dependence on petrochemicals. However, the coating industry remains reliant on petrochemicals due to a lack of knowledge about local and sustainable alternatives. This study explored the potential of wood extractives as precursors for producing high-quality wood coatings. Terpenes were modified through acrylation, and bio-based latexes were synthesized from these modified terpenes. Analysis showed that all tested latexes had conversion levels above 88.5%. The bio-based films were characterized, and their transparency, measured by ultraviolet-visible spectroscopy, exceeded 80%. The good incorporation of bio-based monomers in the latex films was confirmed by thermogravimetric analysis and pyrolysis-gas chromatography-mass spectrometry. Comparative analysis between bio-based and conventional latexes showed equivalent results in particle size, molecular weight, glass transition temperature, and minimum film formation temperature. However, bio-based films exhibited lower hardness. The study suggests that using monomers derived from wood extractives offers a viable alternative to petrochemicals, utilizing abundant forest residues. This approach could address raw material shortages and help make the coatings industry more sustainable by reducing its reliance on petrochemicals.

Este artículo introduce un recurso didáctico diseñado para mejorar la enseñanza y evaluación del electromagnetismo, enfocándose específicamente en el concepto de campos eléctricos. A través de un flujo de trabajo que integra R Markdown y LaTeX, se facilita la creación de problemas variados con valores aleatorios. Esta herramienta es especialmente útil para generar materiales de práctica y exámenes, permitiendo evaluar de manera efectiva el entendimiento de los estudiantes en diversas situaciones físicas. La generación automática de documentos PDF listos para ser utilizados en entornos educativos muestra la versatilidad y eficiencia del recurso. Capaz de cubrir temas desde el campo eléctrico generado por cargas puntuales hasta el movimiento de un electrón en un campo uniforme, este recurso es adecuado para cursos de electromagnetismo a nivel universitario intermedio. Su implementación no solo ahorra tiempo a los docentes en la preparación de material, sino que también enriquece el proceso de aprendizaje de los estudiantes, ofreciéndoles recursos para una preparación sólida.

Organic electrochemical transistors (OECTs) have attracted considerable interest in the context of wearable and implantable biosensors due to their remarkable signal amplification combined with seamless integration into biological systems. These properties underlie OECTs' potential utility across a range of bioelectronic applications. One of the main challenges to their practical applications is the mechanical limitation of PEDOT:PSS, the most typical conductive polymer used as a channel layer, when the OECTs are applied to implantable and stretchable bioelectronics. In this work, we address this critical issue by employing natural rubber latex (NRL) as an additive in PEDOT:PSS to improve flexibility and stretchability of the OECT channels. Although the inclusion of NRL leads to a decrease in transconductance, mainly due to a reduced carrier mobility from 0.3 to 0.1 cm2/V·s, the OECTs maintain satisfactory transconductance, exceeding 5 mS. Furthermore, it is demonstrated that the OECTs exhibit excellent mechanical stability while maintaining their performance even after 100 repetitive bending cycles. This work, therefore, suggests that the NRL/PEDOT:PSS composite film can be deployed for wearable/implantable applications, where high mechanical stability is needed. This finding opens up new avenues for practical use of OECTs in more robust and versatile wearable and implantable biosensors. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide(MoS2) has a special structure and excellent mechanical properties, making it a promising reinforcing filler for polymers. Carbon dots (CDs) have good antioxidant properties, and the addition of CDs during the synthesis of MoS2 can affect its morphology and size. In this work, a new one-step hydrothermal synthesis process was employed to prepare CDs/MoS2 hybrid particles. Thiourea, sodium molybdate, and glucose were employed as sources of sulfur, molybdenum, and carbon, respectively. The structure and morphology of MoS2 and CDs/MoS2 were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), mapping surface scanning (SEM–EDS), and Fourier transform infrared spectroscopy (FTIR). The results show that the prepared 2H-MoS2 is stacked into flower-like spheres with size around 2–10 μm; with the formation of CDs, the size of MoS2 rapidly decreases to less than 1 μm and the CDs are evenly distributed on its surface with mass ratio of 40.2% (CDs in CDs/MoS2). Subsequently, the CDs/MoS2 were used as reinforcing fillers for natural rubber (NR) latex. The results of mechanical properties show that tear strength, tensile strength, modulus, and elongation at break are increased by the addition of CDs/MoS2 in a very lower loading, and the maximum increment ratio is 45.6% and 12.1% when compared to NR-0; the dynamic mechanical analysis and cross-link density results indicated that the CDs/MoS2 can simultaneously improve rigidity and elasticity of NR. The thermal stability results suggest that the CDs/MoS2 shows positive effects on thermal stability of NR. [ABSTRACT FROM AUTHOR]

Hierarchical BiVO 4 /Ti 3 C 2 microcapsules report enhanced solar-driven water evaporation and photothermal-catalytic H 2 evolution activity. The flexible aerogel endows efficient evaporation rates (2.01 kg m−2 h−1) under 1kW m−2 solar irradiation, and the complementary heterostructures present photocatalytic H 2 production evolved after 4 h of reaction is 9.39 μmol. [Display omitted] Desalination processes frequently require a lot of energy to generate freshwater and energy, which depletes resources. Their reliance on each other creates tension between these two vital resources. Herein, hierarchical MXene nanosheets and bismuth vanadate (Ti 3 C 2 /BiVO 4)-derived microcapsules were synthesized for a photothermal-induced photoredox reaction for twofold applications, namely, solar-driven water evaporation and hydrogen (H 2) production. For this purpose, flexible aerogels were fabricated by introducing Ti 3 C 2 /BiVO 4 microcapsules in the polymeric network of natural rubber latex (NRL-Ti 3 C 2 /BiVO 4), and a high evaporation rate of 2.01 kg m−2 h−1 was achieved under 1-kW m−2 solar intensity. The excellent performance is attributed to the presence of Ti 3 C 2 /BiVO 4 microcapsules in the polymeric network, which provides balanced hydrophilicity and broadband sun absorption (96 %) and is aimed at plasmonic heating with microscale thermal confinement tailored by heat transfer simulations. Notably, localized plasmonic heating at the catalyst active sites of the Ti 3 C 2 /BiVO 4 heterostructure promotes enhanced photocatalytic H 2 production evolved after 4 h of reaction is 9.39 μmol, which is highly efficient than pure BiVO 4 and Ti 3 C 2. This method turns the issue of water–fuel crisis into a collaborative connection, presenting avenues to collectively address the anticipated demand rather than fostering competition. [ABSTRACT FROM AUTHOR]

In the modern rubber industry, the major problem is the use of petroleum-derived chemical reinforcements that exploit conventional sources of energy. In this review article, we have discussed the importance of some cellulose-based reinforcements as an alternative to harmful chemicals in rubber composites. The employment of natural cellulosic fillers not only improves the biodegradability of rubber latex but also enhances its mechanical and thermal properties. Such reinforced rubber composites can be used effectively in various sectors, i.e. food packaging, footwear, water purification and sensors. In the last, the current outlook and future perspectives of smart rubber composites in commercial areas are also discussed. [ABSTRACT FROM AUTHOR]

Foam concrete, a type of lightweight concrete, is highly preferred due to its lightness and ease of application. In addition, substitute materials are used in the foam concrete mixture in order to further improve the properties of foam concrete. In this study, the engineering properties of foam concrete produced using liquid latex were analyzed. For this purpose, liquid latex was added to the mixing water. The amount of latex is fixed at 25% of the cement weight. Additionally, the amount of liquid latex added to the mixture was reduced from the amount of mixing water. According to the results, it was determined that liquid latex made positive contributions to the engineering properties of the produced foam concrete. It was found that the water absorption value of latex-added samples decreased significantly compared to the reference sample. In addition, the thermal conductivity coefficient of the samples with latex added was lower than the reference sample. In the microstructural analysis, it was seen that the pores were more homogeneous than the reference sample and no cracks occurred. Finally, the long chain bonds formed by liquid latex in concrete were detected for the first time by SEM image analysis in this study. [ABSTRACT FROM AUTHOR]

This paper describes the effects of incorporating the commercially available phenylurea-based antimicrobial agent S89 to pre-vulcanised natural rubber latex (NRL). The physical properties of the dipped film derived from the S89 incorporated into pre-vulcanised NRL such as antimicrobial efficacy, wettability properties, surface characteristics, surface morphology and tensile strength were further evaluated. The antibacterial activity of S89 in NRL films was tested using the agar disc diffusion method and S89 had been demonstrated to suppress and prevent bacterial growth even at low loading levels. Moreover, the minimum inhibitory concentration (MIC) of S89 was obtained by fitting the inhibition zone diameter and loading of S89 using two mathematical diffusion models, free and dissipative models. In this work, the dissipative model is shown to be the best-described diffusion model for S89. The leaching behaviour of S89 in an artificial sweat was investigated where the leachate of S89 is observed after 20 min of immersion at a very low concentration (0.039 ug/mL). Interestingly, NRL films incorporated with S89 displayed better wettability properties on air facing (AF) surface indicating that the AF surface of the film had been altered to be more hydrophilic. Nonetheless, there were no changes observed to the former facing (FF) surface. In addition, the polarity of the surface was also reduced which corresponds to the contact angle results. Further analysis of the Field Emission Scanning Electron Microscopy (FESEM) surface morphology on the NRL film incorporated with S89 exhibited sufficient miscibility and homogeneity during latex compounding with no agglomeration observed on both surfaces (air and former) and at the cross-sectional surface. Meanwhile, comparative tensile strength (of more than 20Mpa) of NRL films incorporated with S89 was observed for low dosage at 1 phr and 3 phr. In conclusion, antimicrobial natural rubber (NR) films for glove application with satisfactory tensile properties, adequate wettability properties, non-agglomerated surface morphology and good antimicrobial properties were achieved by employing a low loading of S89 in the NRL. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative methodology for evaluating the dry rubber content (DRC) of natural rubber latex (NRL) through the utilisation of transient hot wire (THW) technique. To accomplish this objective, an instrumentation system has been devised and implemented, which operates based on this underlying principle. The proposed approach capitalizes on the significant disparity in thermal conductivity between rubber particles (0.13 W/m-K) and water (0.58 W/m-K). A series of NRL samples obtained from the field were assessed using the developed instrument and their corresponding DRC values determined using conventional weighing-drying technique. The outcomes reveal a strong correlation between measured temperature increments for each sample within a predefined time frame and their respective DRC values. Furthermore, the proposed method offers the advantage of a significantly reduced measurement time, requiring only approximately 10 min to determine the DRC, in contrast to the existing weighing-drying technique, which necessitates around 18 h. Both techniques yield a measurement accuracy of ± 2%. [ABSTRACT FROM AUTHOR]

Methylene blue undergoes decomposition upon the exposure to ultraviolet (UV) light and oxygen to release reactive species such as singlet and triplet oxygen. These reactive species have adequate energy to oxidise and degrade organic materials including natural rubber (NR). In this work, NR latex was exposed to UV in the presence of methylene blue and hydrogen peroxide to produce low molecular weight NR latex. The Mn of NR was reduced from 544 × 103 g/mol to about 6 × 103 g/mol with low gel content. During the photodegradation, the NR chain was cleaved at both C = C and C-C bonds. The molecular structure of LNR was similar to that of the NR but with new functional groups of hydroxyl and carbonyl, resulting from oxidation and chain cleavage. The rubber particles were originally pear-shaped but changed to spherical after the degradation reaction, although their size remained largely similar. [ABSTRACT FROM AUTHOR]

For a long time, skim latex has been regarded as waste from the latex centrifugation process. To recover the rubber, skim latex is coagulated using strong acid due to the high presence of non-rubbers, resulting in products of low quality and unpleasant odour. Additionally, the acid discharged into effluent ponds causes malodour and adversely affects the health of nearby residents. Considering this, a novel method employing a membrane filtration system was utilised, successfully recovering and concentrating skim latex while removing water-soluble non-rubbers. The resulting latex concentrate was then compared to raw skim latex in terms of latex, colloidal, and film properties. Latex properties, namely total solids content (TSC), dry rubber content (DRC), alkalinity, nitrogen content, and gel content were determined. For the colloidal properties, particle size and distribution, zeta potential, and rheological properties (flow and viscoelastic behaviours), were characterised. The film properties assessed included the swelling index, appearance, and tensile properties. Significant improvements in latex properties after concentrating were observed, with both TSC and DRC increasing to 42% and 36%, respectively, while alkalinity, nitrogen, and gel contents decreased to 0.61%, 2.23%, and 54%, respectively. Particle size distribution in raw skim latex (RSL) exhibited a tri-modal distribution, but after membrane filtration, concentrated skim latex (CSL) showed a bi-modal distribution with particle sizes ranging from 0.03 to 0.3 µm and 0.3 to 5 µm and average sizes of 0.07 and 1 µm, respectively. Changes were also noted in zeta potential and rheological behaviour after membrane filtration. The isoelectric point of zeta potential shifted to a higher pH, from 4.2 for RSL to 4.9 for CSL, and the absolute zeta potential values decreased with increasing pH values. CSL also demonstrated a different flow behaviour, fitting well to the Herschel-Bulkley model, unlike RSL, which conformed to the Bingham model. Membrane concentration resulted in significant increases in CSL yield stress, consistency index, and shear thinning behaviour, leading to higher moduli values and indicating increased interaction between CSL particles. Conversely, CSL films prepared via casting swelled more in toluene, approximately two times more than RSL films. Nevertheless, RSL films were more opaque and only became transparent after leaching, indicating high non-rubber contents. Regarding tensile properties, both unleached and leached CSL films exhibited a similar tensile versus elongation profile, with ultimate tensile strength and elongation at break values ranging between 1.4 and 1.6 MPa and 650 and 700%, respectively. [ABSTRACT FROM AUTHOR]

The influence of silver nitrate as an antimicrobial agent on natural rubber (NR) and nitrile butylene rubber (NBR) latex films were investigated. The NR and NBR latex films were prepared using coagulant dipping with an additional dipping procedure was performed prior to wet gel leaching to deposit the silver nitrate solution onto rubber films. Different concentrations of silver nitrate solution were used in the range of 2.5, 5.0, 7.5, 10.0, 12.5 and 15.0 mM, respectively. The degree of microbial inhibition efficiency of the antimicrobial NR and NBR on Staphylococcus aureus (S. aureus) which is a common nosocomial pathogen in combating hospital acquired infections (HAIs) were evaluated. The field emission-scanning electron microscopy (FE-SEM) analyses showed an obvious morphological transition of the silver particle structures were observed as the concentration of silver nitrate increased. On the other hand, the microbial inhibition study using free diffusion and dissipative equations are suggested to determine minimum inhibition concentration (MIC). The antimicrobial study suggested that silver nitrate deposited on the NR and NBR latex films were not influenced by the morphology of silver microstructure which yielded from different concentrations of silver nitrate deposited on latex films surface. Hence, the study effectively demonstrates that antimicrobial inhibition on different antimicrobial latex films results different of MIC values. The tensile strength results of silver nitrate treated NR and NBR latex films also showed no significant reduction on unaged and aged of film's tensile strength, modulus at 300% (M300) and elongation at break (EB). These results indicated that the deposition of silver ion latex films had no negative effect on film's integrity of the NR as well as NBR latex films. [ABSTRACT FROM AUTHOR]

Biofouling, also known as biological fouling, is the accumulation of bacteria, plants, algae, or small animals where they are not needed on surfaces like ship and submarine hulls, equipment like water inlets, pipework, grates, ponds, and rivers that compromise the item's primary function. Anti-fouling refers to a product's capacity to remove or prevent biofouling, such as toxic biocide paints or non-toxic paints. The present study aimed to assess the antifouling efficiency of mangrove and terrestrial species of Acanthus ilicifolius, Avicennia marina, Avicennia officinalis, Excoecaria agallocha, Rhizophora apiculata, Rhizophora mucronata, Ipomea pes-caprae, Cryptostegia grandiflora, Calotropis gigantea, and Rauvolfia tetraphylla. The plant species were identified using the herbarium method. Primary fouling organisms were identified by molecular sequencing. One gram of sample with 10 ml of solvent had been extracted in decoction and maceration extraction methods in various solvents like methanol, chloroform and water. In antibacterial assessment, the methanol leaf extraction of Excoecaria agallocha and Rauvolfia tetraphylla was found active (< 5 cm) than other plant species. Finally, the study found a new antifouling molecule of lycopersene from Excoecaria agallocha. The identified molecule had more than − 6.6 kcal/mol binding efficiency against macro fouler protein. [ABSTRACT FROM AUTHOR]

In this study, the influence that the monomer composition of hydroxyethyl caprolactone acrylate/methyl methacrylate (HECLA/MMA) has on the properties of the latex films, including contact angle, thermogravimetric analysis, and mechanical properties was evaluated. The polymerization process to obtain small particle sizes, good colloidal stability, and polymer films was optimized through the use of pullulan (Pull) and different ratios of HECLA and MMA. The results revealed a substantial impact of the monomer composition and polymerization processes on the particle size and latex film properties. The use of seed latex obtained in situ reduces particle size and particle size distribution. Additionally, it was observed that the contact angle of the polymer films increased as the concentration of HECLA increased. Furthermore, the water absorption of the polymer films exhibited a decreasing trend after reaching an 80/20 monomer composition of HECLA/MMA. An increase in HECLA contents in the recipe showed a reduction in tensile strength, elastic modulus, hardness, and elongation at break. Conversely, higher HECLA contents contributed to improving the thermal properties of the polymer films. Finally, the optimal ratio of HECLA/MMA to improve the thermal degradation and tensile mechanical properties of the polymer film was 50/50 wt%. The results found in this work allow additional data for producing poly(HECLA‐co‐MMA)‐g‐Pull latexes by manipulating the ratios of HECLA and MMA, which can create new potential applications in various industrial settings for a wide range of polysaccharides. Highlights: Poly(HECLA‐co‐MMA)‐g‐Pull with different ratios of HECLA/MMA were successfully obtained.The use of Pull after molar mass reduction had a significant effect on colloidal stability.A reduction in tensile strength and elongation at break was obtained by increasing the amount of HECLA.Thermal stability of the latex films showed a direct relationship with the content of HECLA.Poly(HECLA‐co‐MMA)‐g‐Pull latexes can be used in agricultural applications. [ABSTRACT FROM AUTHOR]

Conductive composites have attracted much attention due to its high conductivity, stretchability, and sensitivity. However, designing conductive composites with relatively stable conductivity under 100% deformation using simple methods remains a challenge. In this work, we employ a simple and straightforward approach to prepare a poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) solution. Based on the conductivity‐optimized PEDOT:PSS (5.95 S/cm), it was combined with carboxylated acrylonitrile‐butadiene rubber latex (XNBRL) to make a flexible conductive material with a unique bottom‐deposited structure. The incorporation of PEDOT:PSS establishes an interconnected conductive network within the XNBR, enhancing both the tensile strength (from 0.31 to 1.24 MPa) and conductivity of the composites. Remarkably, even at 100% strain, the resistance change (ΔR/R0) in the composite remains minimal (<2), demonstrating its exceptional flexibility and high electrical conductivity while maintaining relatively stable resistance during cyclic stretching at 50% deformation. Moreover, the conductive composite can maintain good relative resistance stability under different tensile rates and different strains. This conductive XNBR/PEDOT:PSS composite has promising application prospects in medical devices, which require relatively stable and high conductivity over a relatively large deformation. Highlights: A simple method to increase the electrical conductivity of aqueous PEDOT:PSS.Flexible conductive composite with a small change in ΔR/R0.Enables rigid PEDOT to be used in stretchable electronic devices.Construction of 3D conductive network and bottom deposition structure. [ABSTRACT FROM AUTHOR]

The global plastic consumption, as one of the paramount concerns of our society, opens new paths of investigation in green materials. This study presents contribution to the field with the obtention of natural rubber latex foams (NRLF using egg white powder (EW) as the biostabilizing agent. The route followed to develop these samples is based on a two‐step process, a previous aeration, followed by microwave dehydration. This synthesis route is greener and ecofriendlier than conventional ones due to the use of bio‐based bulk materials, the utilization of microwave radiation which reduces the energy consumption in comparison with conventional heating methods, and the elimination of the vulcanization process typically used when producing latex foams. Herein, a deep study of the effect of EW on NRLF obtained at three water content levels (i.e., 40, 70, 90 phr) is carried out. The density and cellular structure parameters are measured for the formulations of liquid and solid foams to comprehend the stabilization mechanisms due to the presence of the EW and the effect of water content. It has been possible to produce open‐cell natural rubber latex foams with densities as low as 53 kg m−3 and cell sizes as low as 114 μm. [ABSTRACT FROM AUTHOR]

Natural rubber (NR) films with different natural networks—concentrated NR (CNR), deproteinized NR (DPNR), and small rubber particles (SRP)—are investigated to explore the relationship between network structure and film properties using atomic force microscopy (AFM) in PeakForce Quantitative Nanomechanics (QNM) mode. Nitrogen content, gel content, and particle size distribution analyses reveal distinct network topologies in each latex type. Mechanical testing shows variations in tensile strength and crosslink density. AFM analysis provides insights into the crosslink network structures within the pre‐vulcanized latex film. It is found that DPNR and CNR films have a uniform distribution of crosslink networks, with DPNR exhibiting higher Young's modulus values. In contrast, SRP shows varying Young's modulus values, suggesting poor coalescence arising from a harder particle surface and a softer rubber core in an inhomogeneous network structure intrinsic to the non‐rubber components (NRCs) make‐up of SRP latex. This study highlights the pivotal role of natural network structures formed by NRCs in determining the ultimate properties of latex films, which has significant implications for the rubber industry, particularly in the production of latex‐dipped products, medical devices, and bioengineering applications. [ABSTRACT FROM AUTHOR]

Novel cross-linked fluorinated acrylate latex was successfully synthesized via the semi-continuous seeded emulsion polymerization, in which methyl methacrylate (MMA) and butyl acrylate (BA) were used as the main monomers, and dodecafluoroheptyl methacrylate (DFMA) and N–N methylene bisacrylamide (MBA) were used as the fluorine monomer and the cross-linked monomer, respectively. Potassium persulfate (KPS) and mixed surfactants of sodium lauryl sulfate and alkyl alcohol polyether (EFS-470) were used as the initiator and emulsifier, respectively. The structure of resultant latex film was characterized by Fourier transform infrared spectroscopy (FTIR). The latex films were tested by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), contact angle (CA), cross-linked degree and X-ray diffractometer (XRD). The particle size and its distribution of the latex were measured by the nanoparticle size analyzer and transmission electron microscope (TEM). The factors that have an influence on the properties of the latex and the film are investigated in detail. The stability of the resultant latex was good. The average particles of the latex and its distribution were small and uniform, respectively. In comparison with the conventional latex film, the thermal stability and hydrophobicity of the novel latex film were improved obviously. [ABSTRACT FROM AUTHOR]

It is most effective to reduce floor impact noise as close to the sound source as possible. In apartments, there are multiple layers in the floor system, from floor finishing to the structural concrete slab. Apart from the floor finishing, mortar lies at the top layer of the floor system, followed by autoclaved lightweight concrete, insulation, and the concrete slab. The present study aims to identify the reduction characteristics of light and heavy floor impact noises by changing the glass transition temperature of an SBR (styrene–butadiene rubber) latex mortar. To achieve this, structural tests were undertaken to find the appropriate mix proportions of SBR latex in the mortar, meeting the glass transition temperature based on the physical test results regarding the latex mortar. As seen in the study method and process, because this study aimed to both increase and decrease the strength compared to general mortar, a 7% mixture ratio of Tg 4 °C SBR latex was decided upon for the strength increase, while a 5% mixture ratio of Tg −16 °C SBR latex was chosen for the strength reduction. A mock-up specimen was created using the SBR latex-modified mortar according to the identified mix proportions, and the characteristics of light- and heavy-weight floor impact noises of the SBR latex-modified mortar were then examined. Comprehensive analysis of the reduction performance of the floor impact noise revealed that the Tg −16 °C SBR latex-mixed mortar showed a reduction effect of about 2–5 dB for light-weight impact noise and about 7–10 dB for heavy-weight impact noise. [ABSTRACT FROM AUTHOR]

Recent global market disruptions, including the COVID-19 crisis, inflation, and oil crises, have highlighted the need for industries to reduce dependence on petrochemicals. However, the coating industry remains reliant on petrochemicals due to a lack of knowledge about local and sustainable alternatives. This study explored the potential of wood extractives as precursors for producing high-quality wood coatings. Terpenes were modified through acrylation, and bio-based latexes were synthesized from these modified terpenes. Analysis showed that all tested latexes had conversion levels above 88.5%. The bio-based films were characterized, and their transparency, measured by ultraviolet-visible spectroscopy, exceeded 80%. The good incorporation of bio-based monomers in the latex films was confirmed by thermogravimetric analysis and pyrolysis-gas chromatography-mass spectrometry. Comparative analysis between bio-based and conventional latexes showed equivalent results in particle size, molecular weight, glass transition temperature, and minimum film formation temperature. However, bio-based films exhibited lower hardness. The study suggests that using monomers derived from wood extractives offers a viable alternative to petrochemicals, utilizing abundant forest residues. This approach could address raw material shortages and help make the coatings industry more sustainable by reducing its reliance on petrochemicals. [ABSTRACT FROM AUTHOR]

Latex paint is an aqueous dispersion of nano-sized polymer particles that can form a thin film by itself or mixed with rigid particles. We have developed an apparatus that can simultaneously measure drying rate and stress generation and have investigated the film formation process of a latex-only coating layer under convection drying. In the present study, we adopted the same method to investigate the film formation process of the silica–latex coating layer. As a result, we were able to systematically correlate the drying rate change by the equivalent thickness of latex particles accumulated with silica particles at the drying surface. Furthermore, it is unveiled that the drying rate in the former stage depends on drying temperature, while the drying rate changed to be dominated by silica content after the particle-packing layer was formed over the entire coating layer. On the other hand, the model we proposed for stress generation, considering the temperature effect on latex deformability, was found to be applicable to the present experimental system by replacing a portion of deformable particles with rigid particles. [ABSTRACT FROM AUTHOR]