Natural Rubber Latex Research Articles

Optimized titanium dioxide loading for properties of natural rubber latex and acrylic emulsion blends

Blends of prevulcanized natural rubber (PVNR) and acrylic emulsion (AC) were prepared at the fixed PVNR/AC ratio of 30/70. Effects of titanium dioxide (TiO2) addition were optimized across the contents 0, 10, 20 and 30 parts per hundred parts of polymer (php) with respect to various properties. Morphological analysis revealed a two-phase system in which the PVNR particles were dispersed in the AC matrix. Incorporation of TiO2 induced a finer blend morphology in which a part of the TiO2 was located at the interfaces of blend components. The tensile strength increased with initial TiO2 loading and reached its maximum at 10 php loading, with an improvement by about 127% over the blend without filler. However, further increase in filler loading reduced the tensile strength, and the filler tended to agglomerate at those higher loadings. Thermal stability and storage modulus in rubbery region of the blends containing TiO2 were also improved over the unfilled blend, due to the improved morphology and the hydrogen bonds between TiO2 filler and polymer matrix. TiO2 improved water wettability and adhesion of the blend. The maximum peel strengths on wood and metal substrates were about 120% and 26% larger than for the reference unfilled blend. Such drastic improvements suggest that the filled blends may find applications as coating materials.

Natural rubber latex as a potential additive for water-based drilling fluids

The environmental hazards and "carbon footprint" of oil and gas drilling can be significantly reduced by replacing traditional petroleum-based chemical additives with natural materials derived from plants and animals. This paper explored for the first time the interaction mechanism between natural rubber latex (NRL) and bentonite suspensions (BTs) through a series of characterization experiments, as well as the potential applications in water-based drilling fluids (WBDF). The gel viscoelasticity experiments showed that NRL could decrease the consistency coefficient (k) and flow index (n) of BTs, and enhance the shear thinning performance of BTs as pseudo-plastic fluids. In addition, 0.5 w/v% NRL not only increased the critical yield stress and strengthened the structural strength between the bentonite particles, but also facilitated the compatibility of pressure loss and flow efficiency. The evaluation of colloidal stability and WBDF performance indicated that NRL particles could promote the hydration and charge stability on the surface of BTs particles, and optimize the particle size distribution and flow resistance of WBDF under the "intercalation-exfoliation-encapsulation" synergistic interaction. Moreover, NRL can improve the rheological properties of WBDF at high temperatures (<150 °C), and form a dense blocking layer by bridging and sealing the pores and cracks of the filter cake, which ultimately reduces the permeability of the cake and the filtration loss of WBDF.

Latex Allergy - From Discovery to Component-resolved Diagnosis.

Latex allergy is a hypersensitivity response to natural rubber latex (NRL) proteins or rubber chemicals used in the manufacture of latex products. An accurate diagnosis is the first step in the effective management of individuals with latex allergy, especially in high-risk groups, such as healthcare workers and those affected by spina bifida. Diagnosis is based on the clinical history and an accurate allergological evaluation. In the case of type I IgE-mediated hypersensitivity reactions, which can manifest urticaria, angioedema, rhinoconjunctivitis, asthma and anaphylaxis after latex exposure, skin prick tests or latex-specific IgE (sIgE) antibody detection using serological assays can be performed to confirm sensitization. Instead, in the case of contact dermatitis, a patch test can be applied to confirm the presence of a type IV T cell-mediated hypersensitivity reaction to rubber accelerators or additives. Basophils activation tests or challenge tests may be performed if there's an incongruity between the clinical history and the results of in vivo and in vitro tests. The aim of this review is to analyze the current state of the art of diagnostic techniques for latex allergy and algorithms employed in clinical practice and possible future developments in this field.

Does exposure to polymethyl methacrylate bone cement increase the risk of surgical glove failure?

Surgical glove perforation has been linked to a double-fold increased risk of surgical site infection. Infection in the context of arthroplasty can have devastating consequences. In orthopaedics, use of polymethyl methacrylate (PMMA) bone cement is commonplace, and the impact on glove strength and perforation risk is not fully understood. This study aimed to examine the resistance to perforation and thickness of gloves following PMMA exposure, in accordance with the International Organization for Standardization (ISO) standard for glove integrity. Pairs of gloves were separated and randomly sorted into exposure and control groups. Twenty pairs of latex and 40 pairs of polyisoprene gloves were used. Exposure group glove cuffs were in contact with cement from a single surface of the glove for 13 min as cement cured. Force to perforation and glove thickness were tested in accordance with ISO guidelines. Latex gloves were found to have a significantly increased force to perforation following PMMA exposure (10.26 Newtons (N) vs. 9.81 N, P = 0.048). Both polyisoprene under- and over-gloves were shown to have no significant change in strength to perforation post exposure (9.69 N vs. 9.83 N, P = 0.561, and 10.26 N vs. 10.65 N, P = 0.168, respectively). All groups were over the ISO standard minimum strength of 5 N. Exposure of latex and polyisoprene surgical gloves to PMMA bone cement does not appear to increase glove perforation risk and rather may improve natural rubber latex glove strength. This study supports the use of latex and polyisoprene surgical gloves in procedures that involve the handling of PMMA bone cement.

Research on the production technology of rubber epoxy from concentrated natural rubber latex

The results of research on epoxidation technology from concentrated natural rubber latex (CNRL) and in-situ peroxyformic acid, which is synthesised from formic acid (FA) and hydrogen peroxide (HP), are presented in the article. The study investigated the influence of technological parameters of the epoxidation process, such as stabiliser content (nonylphenol ethoxylate, NP9), dry rubber content (DRC), isoprene, stirring speed, reaction time, reaction temperature, and molar ratios of hydrogen peroxide and isoprene (IP), on the epoxy resin content of the product. Research results have shown that the epoxidation reaction with NP9 at 10% takes from 2.5 to 20 hours under the following conditions: latex composition contains from 16 to 24% DRC, stirring speed 100 rpm, reaction temperature response 30 to 70 °C, HP/IP molar ratio changes from 0.7 to 1.3, FA/IP ratio is 0.2, the product was stable and without coagulation. The product was obtained with an epoxy content of 23.4 to 43.6%. This is the basis for building an epoxidized natural rubber (ENR) production process to create a series of natural rubber products that are renewable, environmentally friendly, low-cost, and have many industrial applications.

Preparation and characterization of hydrogels based on glycidyl methacrylate (GMA)‐grafted NR and modified cassava starch as eco‐friendly materials for sustainable agriculture

AbstractEco‐friendly hydrogel was developed using natural rubber latex (NR) and cassava starch (CSt) through grafting modifications to enhance their swelling and water retention by selecting suitable grafting components and improving compatibility. To improve its hydrophilicity and compatibility with CSt, NR was grafted with glycidyl methacrylate (NR‐g‐GMA, NRG). Subsequently, CSt was grafted with acrylic acid (AA) and acrylamide (AM), crosslinked with N,N′‐methylene‐bis‐acrylamide (MBA), and ultimately interpenetrated by NRG to produce CSt‐g‐PAA/NRG and CSt‐g‐PAM/NRG hydrogels, respectively. The obtained hydrogels were characterized by various techniques. Results revealed that CSt‐g‐PAM/NRG exhibited exceptional equilibrium water swelling (Seq) at 2413%, surpassing CSt‐g‐PAA/NRG (416%), and CSt/NR (146%). This was attributed to the synergistic effects of the improved NR polarity and compatibility, the looser structures, the higher rate constant of water swelling (20.06%/s), and the greater compatibility between compositions compared to the CSt‐g‐PAA/NRG system. Therefore, AM was the suitable grafting monomer for the CSt/NRG hydrogel system. Also, the CSt‐g‐PAM/NRG hydrogel exhibited remarkable water retention for up to 30 days with excellent biodegradation (55%) and good biosafety. This study demonstrates a promising strategy for improving swelling capacity (~1600%) and water retention (58%) of biodegradable CSt/NR hydrogels as a low‐cost coating membrane for sustainable agriculture.Highlights Boost of NR hydrophilicity and compatibility via GMA grafting to generate NRG. Fabrication of CSt‐g‐PAA/NRG and CSt‐g‐PAM/NRG hydrogels by semi‐IPN technique. CSt‐g‐PAM/NRG swelling showed a significant improvement over CSt‐g‐PAA/NRG. AM was the suitable grafting monomer for the CSt/NRG hydrogel system. CSt‐g‐PAM/NRG showed good biodegradability and water retention for agriculture.

Enhancement in antimicrobial efficacy and biodegradation of natural rubber latex through graphene oxide/nickel oxide nanoparticles

This work aims to fabricate antibacterial natural rubber latex composites by introducing different ratios of graphene oxide (GO) and nickel oxide (NiO) nanoparticles. The nanocomposites were prepared using latex mixing and a two-roll mill process, followed by molding with a heating hydraulic press. Detailed analyses were conducted to evaluate the rheological, chemical, physical, thermal, mechanical, and electrical performance of the composites. Fourier transform infrared spectroscopy (FTIR) was employed to analyze the interaction among different components, while the surface morphology was examined through the field emission scanning electron microscopy (FESEM) technique. The composites with a loading ratio of 1:2 of GO to NiO (optimized concentration) exhibited the highest tensile strength (24.9 MPa) and tear strength (47.4 N/ mm) among all the tested samples. In addition, the composites demonstrated notable antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans. The thermal stability of the composites was observed up to 315 °C, and their electrical resistivity lies in the insulating range across a temperature span of 25 °C to 50 °C. The research uncovers critical insights into advancing composite materials suitable for diverse applications, featuring inherent antibacterial attributes, robust mechanical properties, resilience to solvent, UV shielding properties, and controlled electrical resistivity capabilities.

Natural rubber latex for the development of high performance cement mortar

Natural rubber latex for the development of high performance cement mortar

Protein‐Mediated ZnO Synthesis for Self‐Healing in Natural Rubber

AbstractNatural rubber (NR) consists of mainly cis‐1,4‐polyisoprene with proteins as notable nonrubber components that significantly influence its properties. A relatively unexplored aspect is the role of these proteins in reducing and stabilizing metal ions to form metallic particles. Here, the NR/ZnO composite is successfully prepared by in situ generation of ZnO in the NR latex for the first time. With the aid of the proteins, the amount of ZnO is slightly higher than that formed in the saponified NR latex (SPNR), where some proteins are removed. Importantly, the noncovalent bonds between the proteins and/or amino acids with the ZnO formed in the NR latex can provide the self‐healing behavior of the NR/ZnO composite. However, heating at ≈40 °C is still necessary for reducing the healing time and increasing the self‐healing efficiency of the composite. Nevertheless, greater noncovalent bonds within NR/ZnO hinder rubber molecular chain interdiffusion and rearrangement essential for self‐healing behavior in uncross‐linked rubber, resulting in lower healing efficiency compared to SPNR/ZnO. This study underscores the significance of proteins and/or amino acids on NR's properties, despite their minor presence. Without sophisticated NR modification, this is a very simple and low‐cost technique to achieve the NR/ZnO composite with self‐healing behavior.

CEMENT MORTARS WITH BOMBYX MORI SILK FIBERS WITH DIFFERENT TYPES OF SURFACE TREATMENTS

The incorporation of natural fibers in cement mortars is an important area of research and development within the construction industry, as it seeks sustainable and ecological alternatives to traditional fiber reinforcements. This paper investigated the effects of different treatments on “Bombyx mori” silk fibers on the mechanical strength and durability of cement mortars, at the same time their architectural possibilities were analyzed. The studied fibers were cut to 20 mm in length, then treated with liquid calcium hydroxide, linseed oil and natural rubber latex. Finally, they were placed in the cement matrix in layers and arranged lengthwise. The mechanical performance and durability of the material were studied through the physical properties of water absorption by immersion, the mechanical properties of compressive, flexural, and impact strength at 7, 14, and 28 days of curing were also studied. The study was complemented with a simulation of alkaline environment of cement using a solution based on sodium hydroxide, measuring the degree of accelerated degradability of the fibers through mass loss. Overall, the results demonstrated that the composite material with fibers treated with natural latex and linseed oil exhibited higher flexural, compressive and impact strength and lower water absorption.

Biobased Interpenetrating Polymer Network Membranes for Sustainable Molecular Sieving.

There is an urgent need for sustainable alternatives to fossil-based polymer materials. Through nanodomain engineering, we developed, without using toxic cross-linking agents, interpenetrating biopolymer network membranes from natural compounds that have opposing polarity in water. Agarose and natural rubber latex were consecutively self-assembled and self-cross-linked to form patchlike nanodomains. Both nano-Fourier transform infrared (nano-FTIR) spectroscopy and computational methods revealed the biopolymers' molecular-level entanglement. The membranes exhibited excellent solvent resistance and offered tunable molecular sieving. We demonstrated control over separation performance in the range of 227-623 g mol-1 via two methodologies: adjusting the molecular composition of the membranes and activating them in water. A carcinogenic impurity at a concentration of 5 ppm, which corresponds to the threshold of toxicological concern, was successfully purged at a negligible 0.56% pharmaceutical loss. The biodegradable nature of the membranes enables an environmentally friendly end-of-life phase; therefore, the membranes have a sustainable lifecycle from cradle to grave.

Fabrication and characterization of latex foam shoe insoles made from novel ammonia-free natural rubber latex concentrate

Fabrication and characterization of latex foam shoe insoles made from novel ammonia-free natural rubber latex concentrate

EFFECT OF EGG WHITE PROTEIN AND WATER CONTENT ON THE STABILIZATION MECHANISMS OF NATURAL RUBBER LATEX FOAMS OBTAINED FROM MICROWAVE RADIATION

The global plastic consumption, as one of the paramount concerns of our society, open new paths of investigation in green materials. This study presents our contribution to the field with the obtention of natural rubber latex foams using egg white powder as bio stabilizing 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 eco‐friendlier than conventional ones due to the use of biobased bulk materials, the utilisation 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. In this work a deep study of the effect of egg white protein on natural rubber latex foams 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 which led to stable final samples in order to comprehend the stabilization mechanisms due to the presence of the egg white and the effect of water content in these systems. With the route developed in this research it has been possible to produce open cell natural rubber latex foams with densities as low as 53 kg/m3 and cell sizes as low as 114 µm.This article is protected by copyright. All rights reserved.

Preliminary evaluation of properties and performance of natural rubber (NR) latex band for microplastic capturing in seawater

Microplastic particles are emerging water-laden waste that cause a worrying concern towards the environment and humans health. Due to its small size and geometry, and uncertain surface properties, the microplastic waste capturing method in water is still evolving. To date, a number of findings report on the emergence of microplastic surface charging, especially when exposed to water environment. In this study, the natural rubber (NR) latex band was utilized to capture the microplastic waste via a surface capturing mechanism. The NR band was produced using a film casting and curing methods. The surface charging mechanism on the NR band was introduced via the usage of high amount of ZDEC accelerator and, periodic stretching and relaxation procedures. In this work, ZDEC was used as an accelerator for the rubber formulation, and surface charge booster for the NR band. The surface charge of the NR band generates electrostatic interaction with the microplastic waste in water. The polypropylene (PP) microplastic was captured via the surface attraction mechanism using the manufactured NR band. Based on FTIR analysis, the presence of PP microplastic can be quantified on the contaminated NR band surface. The NR band shows the improvement in tensile and tear properties and crosslink density, mainly due to high amount of ZDEC used. At ZDEC loading of 20 phr, the NR band recorded the highest surface potential value, and this is owing to the formation of Zn2+ complex ions on its surface. XRF analysis indicates that the increment of Zn content in the NR band with increasing ZDEC content, that suggests the formation of Zn2+ complex ions.

Development of biodegradable packaging films from carboxymethyl cellulose and oxidised natural rubber latex

The present study investigates the biopolymer packaging film developed from carboxymethyl cellulose (CMC) with varying concentrations of natural rubber latex (NR) and oxidised natural rubber latex (ONR) using the solvent casting method. The physicochemical properties of the CMC/NR and CMC/ONR film samples were characterised using FTIR, TG/DTA, DSC, SEM, and XRD analysis. The increased concentration of NR and ONR helped to enhance mechanical characteristics, superior UV resistance, enhanced resistance to oxygen and water vapour penetration, improved dimensional stability, and a reduction in the moisture retention ability of the film samples. The CMC sample film, incorporated with 1.5 g ONR, was found to have more than a 100 % increase in the tensile strength. The tensile value increased from 21.56 MPa to 48.36 MPa, with the highest young modulus of 0.73 GPa and elastic stability of 7.14 %. The incorporation of NR and ONR significantly reduced the super water absorbency nature of the CMC film, and the moisture content values reduced from 21.6 % to ≅ 0.15 % for ONR-incorporated film. Additionally, the CMC/NR and CMC/ONR films exhibited high optical transparency values and were found to be fast biodegradable, substantiating their potential use in various packaging applications. Application of these materials in perishable fruit packaging has shown significant enhancement in shelf life, highlighting their practical efficiency and potential for sustainable packaging solutions.

Characterization and Development of Venipuncture Practice Rubber Model Based for BCG Economy Framework

The Bio-Circular-Green (BCG) economy framework, which integrates economic, social, and environmental aspects for waste management, holds great promise for fostering growth across various sectors in Thailand. Venipuncture, a critical medical procedure, can lead to complications if not performed correctly. This study uses Thailand para latex resources and calcium carbonate extracted from recycled mollusk shells to develop an educational innovation model for venipuncture procedures. Natural rubber latex (NRL) was obtained from Chiang Rai, Thailand. Preserved latex was heated to obtain 60% concentrated latex, then combined with a sulfur solution, and calcium carbonate powder was added in various ratios. Molding used a specialized mold replicating anatomical features of the antecubital fossa, incorporating three prominent veins. The venipuncture practice rubber model was characterized for pH, moisture content, water absorption, tensile strength, and other properties. The model exhibited neutral pH, low moisture content, and notable resistance and elasticity. This study promotes the sustainable utilization of natural latex resources and recycled mollusk shells in developing innovative medical models within the BCG framework. Additional research is required to enhance the human friendliness and realism of the rubber material used in the venipuncture practice model.

Effect of surface modification of microcrystalline cellulose with ionic liquids on natural latex composites

AbstractAs an environmentally friendly biomacromolecular material, microcrystalline cellulose (MCC) enhances the performance of natural rubber latex (NRL) composites. However, MCC has strong polarity, which weakens the interfacial interaction between MCC and the non‐polar NRL matrix and reduces the reinforcing performance due to the many hydroxyl groups on its surface. In this paper, the ionic liquid (IL) modified MCC/IL material was prepared, and AIR‐FTIR, x‐ray diffraction, and XPS photoelectron spectroscopy were performed to detect it from the perspective of environmental protection. And natural latex/microcrystalline cellulose/ionic liquid (NRL/MCC/IL) composites with excellent properties were prepared by latex blending. The activation energy, vulcanization characteristics, basic mechanical properties, dynamic mechanical properties, and filler‐rubber interfacial interactions of NRL/MCC/IL composites were investigated. The results showed that the vulcanization rate constant of NRL/MCC/IL composites increase, the activation energy decreases and the mechanical properties were significantly improved. At the same time, the matrix interface interaction of composites was quantitatively calculated using Ayala parameters. The results showed that the interfacial interaction force of the composite was stronger after an appropriate amount of IL pretreatment. The whole process is not only conformed to the concept of green development, but also broadens the application of MCC in rubber materials.

Wormwood-infused porous-CaCO3 for synthesizing antibacterial natural rubber latex

Wormwood leaf is a traditional Chinese herbal medicine with a high medicinal value and long application history and its essential oil is a high-purity plant oil extracted from Wormwood leaf. Pharmacological research reveals that Wormwood leaf and Wormwood essential oil are a broad-spectrum antibacterial and antiviral drug, which can inhibit and kill many bacteria and viruses. We loaded wormwood extract on porous calcium carbonate (Porous-CaCO3) and introduced it and Wormwood essential oil into Natural rubber latex (NRL), thus synthesizing NRL composites with excellent vitro and in vivo antibacterial effect, cell compatibility and mechanical properties. This NRL material can delay the light aging and thermal oxidation of some mechanical properties, which provides a broader avenue for its commercialization.

Novel IP2C sensors with flexible electrodes based on plasma-treated conductive elastomeric nanocomposites

Ionic polymer-metal composites (IPMC) are devices composed of metallic electrodes and an ionomeric polymer membrane in a ‘sandwich’ architecture and. Their main property is electromechanical actuation or sensing based on the movement of ions. Metallic electrodes are commonly used for their high electrical conductivity, malleability, and chemical resistance. However, the high cost of noble metals, such as platinum, long manufacturing time, and fatigue failure limit their application. Therefore, the replacement of metallic electrodes with conductive elastomeric nanocomposites (CENs) was evaluated to reduce the costs and complexity of manufacturing the device and increase its working life. In this work, carbon nanotubes were used as the conductive fillers. The dispersion to achieve high electrical conductivity was carried out directly in the synthetic or natural polyisoprene rubber latex assisted by surfactant and high-power sonication. To improve the adhesion between the elastomeric electrode and the ionic membrane (Nafion), plasma treatment with atmospheric air was applied as a surface modifier. This treatment improved the hydrophilicity and adhesion of the rubbers by forming oxygenated groups and increasing the surface nanoroughness. In this way, ionomeric polymer–polymer composite (IP2C) devices were fabricated using Nafion and plasma-modified CENs, this type of electrode is unprecedented in the literature for this application. These devices showed displacement and strain sensing capacity at levels close to the conventional IPMC in all tested frequency ranges and applied accelerations. Notably, the IP2C obtained better resolution at low frequencies than the control.

A study on preservatives on the structure and properties of natural rubber latex

A study on preservatives on the structure and properties of natural rubber latex