Latex Dipping Research Articles

Green synthesis of multifunctional natural rubber-lignin nanocomposites: A sustainable approach for waste reduction

Lignin, a valuable biomaterial having an array of exciting properties is increasingly favoured as a reinforcement material in the fabrication of green composites. Reinforcement in biopolymers like natural rubber (NR) using lignin nanoparticles (LNP) is considered a hotspot today. In this study, LNP synthesized via the homogenization method was incorporated into natural rubber latex (NRL) using probe sonication, and NR/Lignin nanocomposites (NR/LNP) were fabricated using latex dipping method. The addition of LNP resulted in significant enhancements in mechanical and antibacterial properties, biodegradability, and ultraviolet (UV) blocking capabilities with the addition of 7 parts per hundred rubber (phr) of LNP, due to the uniform dispersion and effective interaction between NR and LNP. This research demonstrates a versatile pathway for integrating LNP into NR through a green method, enabling the production of eco-friendly NR nanocomposites for multifunctional applications. This pathway contributes to a safe disposal of NR based products.

Elaboration and development of a realistic 3D printed model for training in ultrasound-guided placement of peripheral central venous catheter in children.

Simulation for training is becoming a trend topic worldwide, even if its applications are commonly limited to adulthood. Ultrasound-guided procedures require practice and experience-especially in the pediatric field, where the small size of the involved anatomical structures poses major problems. In this context, a realistic 3D printed pediatric phantom for training of the ultrasound-guided placement of peripheral central venous catheters in children was developed. Starting from Computed Tomography scans of an 8 years-old girl, her left arm was virtually reconstructed-including bones, arteries, and veins-through a semi-automatic segmentation process. According to preliminary results, the most suitable 3D printing technologies to reproduce the different anatomical structures of interest were selected, considering both direct and indirect 3D printing techniques. Experienced operators were asked to evaluate the efficacy of the final model through a dedicated questionnaire. Vessels produced through indirect 3D printing latex dipping technique exhibited the best echogenicity, thickness, and mechanical properties to mimic real children's venous vessels, while arteries-not treated and/or punctured during the procedure-were directly 3D printed through Material Jetting technology. An external mold-mimicking the arm skin-was 3D printed and a silicone-based mixture was poured to reproduce real patient's soft tissues. Twenty expert specialists were asked to perform the final model's validation. The phantom was rated as highly realistic in terms of morphology and functionality for the overall simulation, especially for what concerns vessels and soft tissues' response to puncturing. On the other hand, the involved structures' US appearance showed the lower score. The present work shows the feasibility of a patient-specific 3D printed phantom for simulation and training in pediatric ultrasound-guided procedures.

Sustainable and greener coatings produced from accelerator‐ and sulfur‐free polyurethane dispersion/carboxylated nitrile butadiene latex blends

AbstractThis study is aimed at producing polyurethane dispersion (PUD)/carboxylated nitrile butadiene rubber (XNBR) blends without using accelerators and sulfur. The PUD/XNBR (at blending ratios of 90:10, 80:20, 70:30, and 60:40) was prepared using coagulation and latex dipping technology. The result demonstrated that increasing XNBR in the PUD/XNBR blends increased the zeta potential of the blends up to −71.8 mV. Fourier transform infrared (FTIR) studies show hydrogen interaction bonding exists between XNBR and PUD, which significantly impacts the degree of phase mixing, degree of phase separation and relative change of hard segment separation of the PUD. The surface energy of the PUD blend is reduced from 34.68 ± 0.23 to 22.28 ± 0.63 mJ−2 with increasing XNBR loading. The presence of XNBR had increased the polar component of the surface energy, but a further increase of the XNBR amount to more than 20% had reduced the tensile strength. Overall, loading 20% of XNBR (PUD80) showed the best performance by having an improvement in tensile strength compared to pristine PUD.

Multifunctional role of tannic acid in improving the mechanical, thermal and antimicrobial properties of natural rubber-molybdenum disulfide nanocomposites

Natural rubber is the only biosynthesized rubber and the most prominent of all the elastomers. Insertion of nanofillers into natural rubber matrix has received much research interest because of the enhanced mechanical, thermal, electrical, antibacterial, etc. properties of the final natural rubber nanocomposite. Molybdenum disulfide (MoS2), an important member in transition metal dichalcogenides (TMD) is having excellent optical, thermal, mechanical, electronic and antibacterial properties. The inherent properties of this novel filler was exploited through the preparation of natural rubber-MoS2 nanocomposites via latex dipping method in which tannic acid (TA), naturally occurring macromolecule was used as an exfoliating agent for MoS2. MoS2:TA dispersions were prepared in 1:2, 1:4 and 1:6 ratios by mechanical stirring followed by sonication method for analyzing the optimum amount of exfoliating agent for the preparation of NR-MoS2 nanocomposite. MoS2:TA in 1:4 ratio was found to be the optimum loading for the NR nanocomposite preparation with improved mechanical, thermal and antibacterial properties. The enhanced properties of the NR composites could be attributed to the synergistic effect of both MoS2 and TA. The current study shows the role of TA in tuning the properties of NR/MoS2 nanocomposites that enable their potential utilization in various biomedical applications.

Flow Analysis for Determining Design Parameters of Dipping Tanks in Continuous Latex-Gloves Production Lines Using Computational Fluid Dynamics

In continuous latex-gloves production lines, ceramic formers are lowered into open-channel, latex-dipping tanks. These tanks are known to be critical to the final product quality, so they should be designed carefully. This paper presents a method to determine the optimal design and operating parameters of an island-type, latex-dipping tank. Typically, the conveyor speed is treated a given parameter. The length and the height of the tank can be trivially obtained and considered fixed in this work. The tank width and the driving pressure gradient, on the other hand, are complicated to choose appropriately. This study proposes a systematic approach to obtain the optimal values of these two parameters at each conveyor speed. The analysis consists of three main parts. First, all possible combinations of the parameters are determined by requiring the flow to be laminar and steady. In the second step, Computational Fluid Dynamics (CFD) simulations are conducted to find the combination with the lowest maximum shear stress on the former. Finally, the results from the first two parts are logically combined to give the recommended parameter ranges. One of the practical benefits of the proposed method is that it can be used to find the optimal latex flow rate in the dipping tank of an existing production line. For example, a latex glove production line with the conveyor speed of 0.3 m/s and the tank width of 40 cm should adjust the flow inside the latex dipping tanks to be around 1,940–2,140 L/min.

Effect of Latex Compound Dwell Time for the Production of Prototyped Biodegradable Natural Rubber Latex Gloves

The production of prototyped biodegradable natural rubber (NR) latex gloves with the addition of sago starch as a fillers in latex compounding using Lab Scale Batch Dipping Machine has been investigated. As biodegradable gloves, the progress of biodegradation of NR latex gloves is also being determined through weight loss measurement test. Results showed the optimum dwell time of latex dipping was achieved at 6 sec with optimum tensile properties and within normal examination glove thickness. The weight loss of biodegradable NR latex gloves after one month soil burial showed additional of sago starch into latex compounding can accelerate the biodegradation process.

ANALISIS KINERJA PROSES LATEX DIPPING MENGGUNAKAN TEKNIK CAPABILITY PROCESS (STUDI KASUS: PT DHARMA MEDIPRO)

The quality of product is reflected from the performance of its process. The most frequent issue that occurs in local company today -- is -- most company only focuses on the output regardless the process. It causes the difficulty that occurs in local company to compete with other company in global environment. One of the local companies that has their business shifting up significantly, with the great number of export target and actual export, is PT Dharma Medipro, which has many processes on the production of sphygmomanometer. One of the processes that critical to quality is latex dipping process, where the yield of this process that must be considered is the thickness of the bag component. In order to improve the process, we should first establish the measurement of process performance using capability process technique, which is one of the tools came from statistical process control method. The result indicates that the process is unstable with the value of capability indices Cp = 4,69 ; Cpk = -0,77 ; Cpu = -0,77 ; Cpl = 10,15 ; and Cpm = 0,28, moreover the number of part per million (PPM) that out of the spesification limit reach 912.500 units.

Effect of Drying Time on Mechanical Properties of Natural Rubber Products Filled with Modified Kaolin Prepared from Latex Dipping

Alkanolamide-modifed kaolin was added into natural rubber latex (NRL) pre-vulcanization system at 70°C and the products were formed into films by coagulant dipping method. The dipped films then were dried at 120°C for 15 and 30 min. The effect of drying time on properties of NRL films such as crosslink density, tensile strength, tensile modulus, and elongation at break was observed in this study. Results showed that longer drying time improved the properties of NRL films due to the additional formation of crosslink process in the NRL films. The longer drying time swelled the particles more in matrix as confirmed by Scanning Electron Microscopy (SEM) micrograph.

Filled-NR Conductive Thin Film: A Simple Route of Graphene Dispersion in Natural Rubber Latex

Reliable quantification techniques for graphene oxide (GO) and graphene nanosheets (GNs) in ESD rubber product are limited. We demonstrated an effective ultrasonically−assisted latex mixing (ULM) technique for dispersion of GO and GNs at low concentration (0.5, 1.0 and 1.5 part per hundred of rubber; phr) in natural rubber latex (NRL) to produce NR/GO and NR/GNs conductive thin film. The filled−NR composites were prepared by ULM, followed by latex dipping coagulation. The morphologies from transmittance electron microscopy (TEM) of stabilized GO and GNs dispersion showed successfully dispersion and exfoliation in NR matrix. Compared to pure NR, the tensile strengths of NR/GO and NR/GNs (1.5 phr) increased by ~58% and ~32%, respectively, while there were decreased in the %elongation at break and were no significant change in the force at break. In case of studying the electrical properties, sheet resistances of filled−NR composites declined with the incorporation of GO and GNs. However, the NR composite with 1.5 phr of GNs showed the best conductivity.

Latex Dipping Machine PLC Control and Its Programming

Latex dipping machine is based on a latex patent products new-production condom and the development of the machine. The latex dipping agencies combined with production condom mechanism. First it realized a 3-dimensional accurate localization system using stepping motors. SIMATIC S7-200 series programmable controller, motion module EM253 and stepping motor are tied in wedlock to realize allocation of 3-dimension of X axis and Y axis and Z axis. Through the PTO pulse of Siemens S7-200 PLC controller and combined with the use of EM253 module, through the mould precise control programming soak glue and roll edge to achieve the control mold of rotation and swinging the uniform distributed latex. And the system has applied successfully in foreign-funded enterprise of Singapore.

Surface nanostructure of Hevea brasiliensis natural rubber latex particles

Natural rubber (NR) from the Hevea brasiliensis tree is the main commercial feedstock for rubber and latex dipping industries. NR latex particles in a matured commercial latex concentrate are stabilized by charged groups derived from proteins, long-chain fatty acid soaps and polypeptides adsorbed on the particle surface. The colloidal stability of the latex is extremely sensitive to pH as well as to the ionic environment of the dispersing medium. Previous work on particle microelectrophoresis has shown that the charge on the particle surface is derived mainly from carboxylic groups of long chain fatty acids ( ca. 86%). Freshly collected field latex from the tree, on the other hand, is believed to be stabilized by proteins and phospholipids before hydrolysis sets in upon leaving the tree. The exact arrangement of the adsorbed proteins and phospholipids and the thickness of this adsorbed layer have yet to be successfully determined. The present study has been focused on unraveling the arrangement of these proteins and phospholipids on the particle surface of a freshly tapped NR latex. In order to visualize these molecules, they were imaged using phase contrast atomic force microscopy (AFM). Moreover, the molecules in the particle were labeled with fluorescent Rhodamine B (RB) and uncharged fluorescein-5(6)-isothiocyanate (FITC), and monitored by confocal laser scanning microscopy (CLSM) thereby permitting an in situ observation of their locations on and inside the particles. The selective labeling of the proteins and phospholipids with RB and FITC in protein-free as well as in protein-and-lipid-free latex particles permitted an unequivocal determination of their presence both on the surface and in the interior of the particles. An indentation study of the surface layer of the original untreated NR particle was also carried out to confirm the hypothesis of a core–shell structure with a mixed layer of proteins and phospholipids surrounding the hydrophobic core of polyisoprene particles. According to the obtained results, the surface of the particles in freshly tapped latex is distinctly different from that of a matured latex concentrate.

Use of Latex Teat Dip with Germicide During the Prepartum Period

The efficacy of an acrylic latex barrier teat dip with germicide on new infections at parturition was tested on 113 cows and heifers during the prepartum period. A split udder design was used in which right quarters were undipped controls and left quarters were dipped with latex dip once daily for approximately 14 d prior to parturition. Distal streak canal swabs were taken from all quarters prior to the beginning of dipping, and all cows were quarter sampled in duplicate at drying off, parturition, and the first 5 consecutive wk of lactation. All quarters received antibiotic therapy at drying off. Excluding infections detected by distal streak canal swabs, the number of new infections at parturition in control and dipped quarters was 32 and 36. New infections at parturition in control and dipped quarters were Staphylococcus aureus, 2 and 2; coagulase-negative staphylococci, 8 and 9; stretptococci, 10 and 12; coliforms, 8 and 8; and others, 4 and 5. Differences were not significant. These results suggest no benefit to use of prepartum latex teat dip with germicide on new infections at parturition.

Adhesion between Rayon and Nylon cord and an elastomer matrix

Two types of cord, namely Nylon and Rayon, with variation in the number of twists per inch in a natural rubber (NR) compound with and without a dry-bonding system are considered. The dip systems used for the cords are based on resorcinol formaldehyde latex with three latex systems: NR/VP, SBR/VP and XSBR/VP. The natural rubber/vinyl pyridine latex system gives rise to higher bond strength, and carboxylated styrene butadiene rubber/vinyl pyridine latex system to a lower bond strength. As the number of twists increases, the adhesion value increases for both Nylon and Rayon cords. The adhesion is further enhanced by the incorporation of the dry-bonding system in the compounds. Flex life improves as the number of twists increases, and is further enhanced by the use of a NR/VP latex dip system and the dry bonding system. However, with highly twisted cords, breakage of the cords is observed under cyclic tension stress. SEM studies reveal that the low flex life of the less twisted cord composites is probably due to the lower adhesion values and fibrillation under cyclic stress. Improved flex life and adhesion of the highly twisted cords may be due to the more mechanical anchorage of the cords in the elastomeric matrix.

Study of the reaction of resorcinol, formaldehyde, and ammonia

AbstractLatex dip adhesives for nylon and rayon tire cords are prepared by reacting resorcinol and formaldehyde in aqueous solution in the presence of a catalyst for a specified time and then adding a butadience–styrene–vinylpyridine latex. Ammonia improves the stability of the latex and increases the adhesion of rubber to cord. However, a white precipitate forms if ammonia is added before the resorcinol and formaldehyde have reacted sufficiently. This paper is study of the nature of this precipitate and the conditions for its formation. By measuring the heat of reaction of formaldehyde and ammonia and, subsequently, of mixtures of formaldehyde and resorcinol to which varying amounts of ammonia were added, information on the reaction mechanism has been obtained. Ammonia reacts rapidly with formaldehyde to form an unstable intermediate, presumably trimethylolamine, which then reacts further with resorcinol to form trisdihydroxybenzylamine. This compound is also very reactive and condenses withmore ammonia and formaldehyde to give a polymer of low solubility, the composition depending on the amounts of ammonia and formaldehyde available for reaction. Elemental analyses support this concept. Primary and secondary amines react in a maner similar to ammonia.

Latest for Detroit! New latex dip paints get durability boost from "Dutch Boy" research

RETURN TO ISSUEPREVAdvertisementNEXTLatest for Detroit! New latex dip paints get durability boost from "Dutch Boy" researchCite this: Chem. Eng. News 1958, 36, 50, 95Publication Date (Print):December 15, 1958Publication History Published online6 November 2010Published inissue 15 December 1958https://doi.org/10.1021/cen-v036n050.p095Copyright © 1958 AMERICAN CHEMICAL SOCIETYArticle Views7Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (114 KB) SUBJECTS:Durability Get e-Alerts

Behavior of Rayon Tire Cord during Latex Dipping

Abstract A study of the behavior of two types of rayon tire cord during latex dipping was made with a laboratory treating unit. Results of the tests showed certain facts. The concentration of the latex bath increased as rayon tire cord was dipped. No change occurred in dipping cotton. Based on the weight of cord dipped, sulfonated oil cord caused a higher increase in bath concentration than waxy ester cord; based on the weight of latex consumed, the order was reversed. Waxy ester cord had relatively slow wetting-out characteristics compared to sulfonated oil cord; compared to both, cotton is infinitely slow. The ratio of water-to-solids pickup with both cords is identical for all concentrations of the bath examined. Because of this characteristic both cords behave identically in the bath provided the squeeze rolls are adjusted to give equal solids pickup. Ratio of water-to-solids pickup decreases as the concentration of the bath increases. Stable fibers, both cotton and rayon, need no adhesive treatment for satisfactory bonding to rubber. In contrast, continuous filament rayon cannot be used until it is treated. Adhesion is a function of solids pickup. Sulfonated oil cord picks up two to four times as much solids as waxy ester cord under a variety of conditions because of better wetting-out properties. By changing either the squeeze-roll pressure or the bath concentration solids pickup is changed. Cord produced from staple rayon picks up more solids than continuous filament cord because of protruding fiber ends. An increase in concentration of the latex bath causes an increase in solids pickup. Viscosity acts similarly. Particle size has no appreciable effect on solids pickup. Surface tension does not affect solids pickup by waxy ester cord; it does affect sulfonated oil cord to a minor degree at or below 46 dynes per cm. An increase in cord tension through the latex bath decreases solids pickup. As the speed of processing is increased, solids pickup increases. A wiping action on the dipped cord decreases solids pickup. No relation between contact time and solids pickup could be established.

Behavior of Rayon Tire Cord during Latex Dipping

Behavior of Rayon Tire Cord during Latex Dipping