Types Of Latex Research Articles

Rubber latex‐assisted improvement of nano‐zinc oxide dispersion in high density polyethylene matrix: A study on the effect of latex type and proportioning

AbstractHerein, the type of latex and its ratio to nano‐zinc oxide have been investigated for the effectiveness of latex‐assisted dispersion of nano‐zinc oxide. By analyzing the mixed state of latex and nano‐zinc oxide after the addition of coagulants, as well as physical and scanning electron microscope of corresponding composite materials, it was determined that natural rubber latex has the best auxiliary dispersion effect. Based on this result, the effect of the ratio of natural latex to zinc oxide nanoparticles was further investigated. Result showed that when the ratio of the two was too small, the nano‐zinc oxide in the rubber particles would cause the natural rubber latex to fail to solidify rapidly. When the ratio of the two was 2 : 1, the natural rubber latex rapidly solidify and encapsulate the nano‐zinc oxide. Eventually dispersed uniformly in the high density polyethylene matrix. Based on these results, the corresponding composites have a corrected notched impact strength of 142.6 kJ⋅m−2 and a tensile strength of 24.2 MPa. They also have excellent electrical insulation properties. These two properties are retained at a high rate after aging., This work further refines the latex‐assisted dispersion method and can improve the potential of the method for industrial applications.

Unveiling the Hidden Networks: AFM Insights into Pre‐Vulcanized Hevea Latex and Its Profound Impact on Latex Film Mechanical Properties

AbstractNatural 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.

Dispersion polymerization of AM-AMPS-DAM-DOH and its sand control property

Sand production in oil wells is a common challenge during the oil extraction process. Water-soluble polymers have attracted attention due to their low toxicity, cost-effectiveness, ease of direct injection, and excellent thermal stability. However, the dry polymer injection process commonly used in offshore oil fields is complex. Therefore, this paper employs acrylamide (AM), 2-acrylamide-2-methylpropane sulfonic acid (AMPS), a dihydroxy monomer (DOH), and a functional monomer (DAM) containing ketone groups and self-crosslinking properties as monomers. A polymer latex type sand control agent was prepared through dispersion polymerization for direct application on offshore platforms. This paper utilizes flocculation time and maximum sand free flow rate as inspection indicators and utilizes both the one-factor-at-a-time method and the surface response method to optimize the synthesis conditions of the sand control agent. The optimal synthesis conditions are obtained: total monomer concentration of 9.15 wt%, DOH concentration at 10 wt% of the total monomer concentration, ammonium sulfate (AS) concentration of 27.02 wt%, dispersant concentration of 2.13 wt%, initiator concentration at 0.25 wt% of the total monomer concentration, reaction time of 12 h, and reaction temperature of 40 °C. Under the conditions of concentration ≥2000 mg/L and curing time ≥4 h, the sand control agent is suitable for sand stabilization under formation conditions of temperatures between 50 and 80 °C, pH levels ranging from 3 to 9, salinity <30000 mg/L, and sand particle size of ≥100 μm. The research results of this paper can serve as a valuable reference for the control of oilfield sand production.

Storage-stable and self-crosslinkable combinations of boronic acid containing polymers and diol containing polymers enabled by the latex system

Boronic ester is a kind of well-known and active dynamic covalent bond. Yet preparing an even boronic ester crosslinked network from boronic acid containing polymers and diol containing polymers remains challenging because the reaction between boronic acid and diol is so fast that by now blocking boronic acid/diol (in the form of boronic ester) or special mixing procedures are required. In this work, a series of storage-stable and self-crosslinkable combinations of boronic acid (2%, 4% and 8%, in mol%) containing polymer latices and diol (2%, 4% and 8%, in mol%) containing polymer latices were achieved by simply mixing the two types of latex dispersions, without using any blocking agents or special mixing procedure. In the combined dispersions, water as the dispersion medium isolates boronic acids and diol groups, while the combined latices can undergo self-crosslinking via the encounters of boronic acid and diols during the latex film formation. Target synthetic products were confirmed by NMR, UV–vis absorption, FT-IR and Raman spectra. The combined latices have simultaneously ensured the even mixing, storage stability (60 °C for 1 month or room temperature for 6 months) and self-crosslinking (examined by DMA, Soxhlet extractions, up to 97% gel content). The method of respectively preparing and then combining the two types of latices is better in polymerization stability, toughness, and wettability, compared to the method of preparing crosslinked polymer with the comparable divinyl boronic ester crosslinker (1%, 2% and 4%, in mol%). With these advantages, the method of combining such highly reactive polymers by utilizing the features of latex systems is inspirational in the fields of colloid science and reactive polymers.

Effects of latex type and processed-mica waste loading on the structural and thermo-physical properties of natural rubber latex foam composites

Mica waste, a type of commercial waste produced in bulk quantities by the mica mining industry, was processed and added to Natural Rubber Latex Foams (NRLF) made of centrifuged and creamed latex. Following the Dunlop method, NRLF composites with various Processed Mica Waste (PMW) loadings (0, 2, 4, 6, 8, and 10 Phr) were prepared, and the thermo-physical characteristics were compared. Thermal conductivity, electrical resistivity of NRLF against the latex type and mica loading were compared for the first time. NRLFs prepared using creamed latex exhibit 33 and 50 μm (width and height) cell diameter, 3 ibf hardness, 281 % swelling index improvements and 0.05 Wm−1K−1 thermal conductivity, and 1 °C glass transition temperature (Tg) reductions than centrifuged NRLF and indistinguishable electrical resistivity. With the addition of mica (0–10 Phr), both NRLF types showed a similar ascending trend in hardness (42 ibf), water absorption (16 %), Tg (7 °C), thermal conductivity (0.54 Wm−1K−1), electrical resistivity (69 × 103 Ω m) with decreasing gel time (3 min) and swelling index (550 %). The key objective of this research was to prepare PMW-filled NRLF and compare structural, electrical and thermo-physical properties, for the first time, against mica content and latex type.

Synthesis and Characterization of Colloidally Stable Self-crosslinking Water-based Anticorrosive Polymer at Room Temperature

The emulsion polymerization of butyl acrylate (BuA), styrene (St), and 3-isopropenyl-α,α-dimethylbenzyl isocyanate (IPMBI) is presented in this work. Obtain colloidally stable latexes for the poly (BuA/St/IPMBI) system during polymerization and storage for use in a water-based coating formulation. A series of semicontinuous polymerizations were also performed to investigate the effect of comonomer composition (w/w) in the feed (BuA/St) on conversion. The particle diameter (Dp), particle number (Np), hydrolysis of the IPMBI’s isocyanate groups, stability and storage properties. Films were created in which the effect of comonomer composition was also investigated, the glass transition temperature (Tg) was determined, the gel content was selected, and the mechanical properties and capacity as a barrier to water vapour and oxygen were assessed. Another series of reactions, on the other hand, was carried out in which the effect of the IPMBI content (1.5, 3.5, and 5.5%) was studied using a constant composition BuA/St=60/40. The studies conducted are the same as those mentioned for the effect of comonomer composition in feed. With increasing IPMBI percentage, slight differences in conversion, Dp, and Np were observed; the latices undergo hydrolysis during polymerization and storage. Colloidal stability, on the other hand, was preserved. The mechanical properties of the films improved as the percentage of IPMBI increased, while the boundary characteristics to moisture and oxygen improved when compared to the white film (0% of IPMBI). Finally, the formulation of a self-crosslinking water-based coating at room temperature using the previously obtained latex as a binder is reported; the coating demonstrated excellent adhesion, scratch hardness, and gloss regardless of the type of latex used.

The Presence of Microplastics in the Gills and Gastrointestinal Tract of Mackerel (Rastrelliger Kanagurta Cuvier, 1816) from Jakarta Bay, Indonesia.

This study examined the characteristics of microplastics (MPs) in the gills and gastrointestinal tract (GIT) of mackerel (Rastrelliger kanagurta) captured in Jakarta Bay, Indonesia. All 120 fish contained MPs, with fragment > fiber > film being the most prevalent types, in that order. The total abundances of fragments, fibers, and films in the gills were as follows: 4.8 ± 1.6, 1.0 ± 0.7, and 0.3 ± 0.3, respectively. The total abundances of fragments, fibers, and films in the GIT were 5.9 ± 2.3, 1.3 ± 0.8, and 0.4 ± 0.4, respectively. Statistical analysis showed that the abundance of fragments, fibers and films in both the gills and GIT of mackerel did not differ significantly between sampling locations. In the gills and GIT, MPs with sizes less than 0.1mm and MPs that were black in color were most prevalent. Fourier transform infrared (FTIR) spectroscopy tests on MPs from the tissues of mackerel showed that there were 8 different types of MP polymers, namely, latex, nylon, polymethyl methacrylate (PMMA), cellulose acetate (CA), polyurethane (PU), polycarbonate (PC), polystyrene (PS), and polytetrafluoroethylene (PTFE). Latex and polycarbonate were detected in fish samples from Jakarta Bay.

Insect-trapping glues made of natural rubber: Effects of nonrubber components and rubber molar mass on performance

An easy-to-prepare glue was produced from natural rubber (NR) latex and environmentally benign chemicals for use in control of insect pests in greenhouses. The effects of non-rubber components and the molar mass (MM) of NR in the latex and the glue on adhesion performance of the glues are reported. Glues were produced using five latex types: commercial high-ammonia concentrated latex (HA), fresh latex (FL), skim latex (SK), urea deproteinized latex (UD), and saponified latex (SP). The latexes’ characteristics (e.g., protein content, phospholipid content, gel content, and molar mass of NR chains) and the characteristics of the resulting glues (i.e., drying time, molar mass of NR chains, and adhesion performance) were evaluated by principal component analysis (PCA). The NR glues made of HA and SP latex types were found to have an adhesion performance comparable to commercial insect trapping glues. The HA latex was natural, more economical, and required less processing than the SP latex. PCA demonstrated that the adhesion performance of the glues correlated strongly to the gel content and the molar mass of the NR chains in the glue and the latex. Increased values of all these variables improved the cohesive strength of the glue. The HA glue was tested in a greenhouse to confirm its effectiveness: it showed an insect capturing efficacy of ∼68% of a commercial glue. The lower performance was caused by an absence of vulcanization, leading to creep behavior and degradation of the rubber chains in the hot environment of the greenhouse.

Aqueous polyacrylate latex nanodispersions used as consolidation agents to improve mechanical properties of Prague sandstone

This investigation aims at assessing the potential of polyacrylate latex nanodispersions as consolidation agents for sandstones. Four different latex types, implementing polymer fluorination and chemical crosslinking, have been synthesized at the scope and fully characterized. The Prague sandstone employed in this study has been selected as an example of highly porous stones used as building materials for many historical monuments. Two different concentration levels of nanodispersions have been adopted. The consolidated stone samples have been tested using a combination of physical-mechanical tests and microscopic observations. Compared to the non-treated samples, significant increments of mechanical properties (e.g. up to 3.3 times higher bending strength) have been detected after the consolidation treatment with concentrated products. Moreover, when 10 times diluted latex nanodispersions have been applied, the improvement of mechanical properties has still been significant, while moisture transport properties, such as water absorption, have been found to be comparable with those of the untreated sample. Fluorinated polymers imparted better hydrophobic properties with a contact angle above 100°. Observations using a scanning electron microscope revealed the good filling and bridging capacity of the applied consolidation agents. As demonstrated, by acting on the polymer structure, that is, by tuning the degree of crosslinking, polymer fluorination and gel content, the properties of these novel polyacrylate latex nanodispersions can be tailored to the specific stone and type of decay in order to improve the effectiveness of the treatments and obtain the desired final properties. The flexibility of their chemistry offers new opportunities for preserving objects of cultural heritage that are also at risk due to the ongoing climate change.

Gutta percha, natural rubber and balata-chemical characterization of polyisoprenes in the context of cultural heritage

Gutta percha, natural rubber, and balata are latexes produced by tropical trees that since the mid-nineteenth century have been extensively used commercially and in the creation of artworks and daily use objects. All three latexes are stereoisomers of polyisoprene that differ in their molecular structure. In gutta percha and balata, the molecular functional group is in the trans- position; in natural rubber, it is in the cis- position. This difference in their molecular structure affects the physical properties of these materials and their aging, turning natural rubber tacky and gutta percha brittle. Commercially focused analysis of natural polyisoprenes has typically used chemically modified materials. The present study characterizes natural, chemically unadulterated latex harvested from trees, aiming to differentiate the cis- and trans-forms. The analysed materials comprised fresh latexes harvested in Malaysia and Indonesia, naturally aged botanical samples, some over 100 years old, and minimally processed 10-year-old commercial stock; a total of 50 samples were examined, out of which 23 are discussed in detail. The harvesting practices of latexes were recorded during fieldwork in Southeast Asia in 2015–2019, in Cipetir (Tjipetir), on Lingga Island in Indonesia, and in Malay rubber plantations. The harvesting methods are the first indicators as to the type of latex harvested based on the pattern of incisions and time of coagulation upon exposure to air. The interviews of tappers, especially of gutta percha and balata, serve as a record of a disappearing craft. Therefore, this fieldwork report contributing to a general knowledge of working methods with natural latexes is of particular value considering the scarcity of published records. The laboratory analytical study of trans- and cis- forms relied on nuclear magnetic resonance (NMR) spectroscopy, which is the most accurate method to unambiguously determine the stereo chemistry of each polyisoprene. The characteristic spectroscopic features of cis- and trans-positions were clearly shown in all samples, in fresh latex, in over 100-year-old material, and in early twentieth century artifacts. This result indicated that the aging of the polyisoprenes does not prevent the identification of their stereochemistry. This analytical work is the first thorough examination of gutta percha, natural rubber and balata in the context of cultural heritage to guide preservation strategies for objects made of these materials.

Study of keto-hydrazide crosslinking effect in acrylic latex applied to Portland cements with respect to physical properties

Polymer-modified Portland-based composites are of interest for specific applications, in reason of their properties. There are different types of commercial additives and waste polymer-based materials applied to cement-based composites, however, their impacts on the environment are debatable. This work has prepared new acrylic latex additives with and without keto-hydrazide crosslinking from standardly available low-cost raw monomers. The influence of their incorporation into Portland cement-based fine-grained mortars has been investigated. The obtained results indicate that the highest effect on heat flow evolution changes has been detected in the case of latexes without crosslinking. The incorporation of both latex types into produced cement composites resulted in a significant increase in open porosity connected with the gradual decrease in mechanical resistance, especially the compressive strength. On the other hand, an important mitigation of liquid water transport properties of latex-modified composites has been achieved, and such properties can be tuned according to the used latex type and its concentration. The developed latex cement-based composites may find utilization as special materials for structures or products for water-loaded constructions or in areas with high concentrations of water-soluble salts or other pollutants.

A comparative study on mica waste‐filled natural rubber foam composites made out of creamed and centrifuged latex

AbstractA comparative study on processed mica waste (PMW) filled natural rubber latex foams (NRLF) made out of centrifuged latex and creamed latex was conducted. The morphological, mechanical, and degradability properties of the composites were studied. The PMW was incorporated at 0, 2, 4, 6, 8, and 10 phr loading. Morphological studies revealed that both types of composites possess open‐cell structures. However, creamed latex based foam rubber composites showed foam structures with much larger cell sizes. PMW loading showed similar influences on the properties of the foam composites, irrespective of the latex type used. Increasing filler loading increases tensile strength, modulus at 100% elongation, tear strength, compression set, shrinkage, biodegradability, and antibacterial properties and reduces elongation at break and extractable protein content while offering a slightly dark color to the composites. It was also found that the creamed latex based foam rubber exhibits lesser extractable protein content and slightly inferior properties in tensile strength, shrinkage properties and color compared to centrifuged latex based foam rubber. However, it was shown that type of latex does not influence biodegradability, antibacterial properties, and color retention. Thermogravimetric analysis results confirmed the thermal resistance and reinforcing ability of mica in both NRLF composites.

Simultaneous quantification of volatile fatty acids and nonvolatile organic acids in Hevea brasiliensis latex.

The current method used in latex industries to determine the volatile fatty acids contents of Hevea brasiliensis latex is steam distillation. However, the accuracy of the method has been debated for some time. We assessed the accuracy of the method and developed a new, more reliable high-performance liquid chromatographic method of determining acids in latex. The volatile fatty acids (formic, acetic, propionic, butyric, and valeric acids) and nonvolatile organic acids (oxalic, malic, lactic, citric, and succinic acids) in latex are directly determined simultaneously for the first time with high sensitivity and without losses during sample preparation. To avoid errors from derivatization, an acid-resistant Prevail HPLC column and a gradient mobile phase of 25mM potassium dihydrogen phosphate (pH 2.5) and acetonitrile were employed. Under optimum conditions, the calibrations of both types of acids demonstrated satisfactory correlation coefficients of ≥0.990, with limits of detection ranging from 0.02 to 395mM. The developed method demonstrated the profiles of acids in field and concentrated latex of the same batch. Moreover, the evolution of the profiles of all studied acids in both types of latex during a 3-month period was also revealed.

The Characteristics of The Asphalt Concrete Wearing Course (AC-WC) Using SIR20 Solid Rubber Compound

Mixing natural rubber with asphalt can improve asphalt performance resistance to cracks and increase asphalt attachment to aggregates. The latex type is a natural rubber that can be directly used as an additive in asphalt mixture. Mixing asphalt with natural rubber and latex type in solid forms such as Standard Indonesian Rubber (SIR) should be made first in rubber asphalt master mixture (called masterbatch). So that the mixture is more homogeneous, making it more accessible in the process of mixing into the asphalt. This study aims to determine the characteristics of the Asphalt Concrete Wearing Course (AC-WC) using SIR 20 solid-rubber compound in the form of a masterbatch. This research began with the manufacture of masterbatch, which is mixing SIR 20 solid-rubber compound and asphalt into a kneader machine with a ratio of 1:1. It is then formed into a black sheet using an open mill machine, after which it is inserted into the enumerator machine to produce small cylindrical granules measuring 5 mm. Then the masterbatch granules are included in the asphalt mixture with some variations of asphalt content to obtain the Optimum Asphalt Content (OAC) value. Based on the OAC value, test objects made with several SIR 20 solid-rubber compound content variations. The Marshall test has conducted to determine the value of stability and flow. Based on the optimum contents obtained, test objects are created for Wheel Tracking Machine (WTM) testing to determine the value of dynamic stabilities. From the results of this study, it is known that the use of SIR 20 solid rubber compounds in the form of masterbatch can improve the performance of AC-WC concrete asphalt mixtures, with the optimum SIR 20 solid rubber compound content of 7%.

Influence of Polymer Latexes on the Properties of High Performance Cement–Based Materials

The application of polymer latex provides an additional approach when optimizing the properties of high–performance cement–based materials. Given that cement–based materials are extraordinarily sensitive to the characteristics and relative content of polymer latexes, identifying their influence is essential for application. This paper investigates the impact of polymer latex types and its relative content on the mechanical properties, hydration product, pore structure, and drying shrinkage of cement–based materials with a low water to binder ratio. The results showed that the mechanical properties, pore structure, and drying shrinkage of the styrene butadiene latex modified samples were better than those of ethylene vinyl acetate latex and silicone acrylic latex modified ones. Incremental increases to the polymer to cement ratio induces a slight reduction on compressive strength, and styrene–butadiene latex promotes tensile strength. Polymer latex hinders the transformation from ettringite to monosulfate, reducing the bound water and portlandite generated. Increasing the polymer content induces more significant stretching in the vibration peak of SO4 from ettringite. Further incorporation of polymer latex contributes to ettringite precipitation and the decline of harmful pores. Polymer addition also results in lower drying shrinkage compared with the reference group.

Effect of SBR and XSBRL on water demand, mechanical strength and microstructure of cement paste

This paper aims to disclose the properties and mechanism of latex-modified cement materials. Two kinds of latexes were selected, SBR and XSBRL, to prepare the modified materials. Grouting materials containing different latexes and proportioned for varying water-to-cement ratios were investigated, and testing was made under four different curing conditions. Test results had shown that the latexes significantly reduced the water demand and changed the setting time. The improvement of mechanical properties was related to the type of latex, curing condition, and dosage. The addition of 5% latex positively influenced reducing the porosity and restraining the chloride ion penetration. SEM and EDS analysis show that the properties of the polymer-modified mortars were influenced by the polymer film, cement hydration products, and the chemical reaction between the organic and inorganic phases.

The assessment of durability, coefficient of thermal expansion, and bonding strength of latex modified mixtures in repairing restrained concrete pavements

ABSTRACT In this study, two types of latex, Styrene–Butadiene Rubber (SBR) and Poly-Vinyl Acetate (PVA) were used as repair materials, and their various properties were examined. The assessments utilised Latex Modified Concrete (LMC) in ratios of 10%, 15%, and 20% to the weight of cement to investigate the properties of fresh and hardened concrete. The mechanical strength and durability of concrete were evaluated using porosity, water absorption, shrinkage, bonding behaviour, Coefficient of Thermal Expansion (CTE), and scaling resistance. The results indicated that LMC's mechanical properties improved, whereas its compressive strength decreased. The bonding strength between the LMC and the older concrete was more significant than between the Ordinary Portland Cement (OPC) and the substrate concrete. The SBR sample outperformed the PVA sample according to shrinkage and CTE results. Additionally, scaling resistance to deicing chemicals on concrete surfaces exposed to freezing-thawing cycles was satisfactory in concretes modified with both latexes.

Non-sterile examination gloves and sterile surgical gloves: which are more sustainable?

Healthcare professionals should consider environmental sustainability when using personal protective equipment (PPE). One of the most frequently used items of PPE in medical settings are gloves. This study aims to quantify the environmental impact of sterile versus non-sterile gloves using the life cycle assessment (LCA) methodology. This study used three glove types: non-sterile gloves and sterile gloves (latex and latex-free). Sixteen different environmental impact categories were used to demonstrate the impact of each glove type. Non-sterile gloves had the least environmental impact in all categories. The two types of sterile gloves, non-latex (synthetic rubber) and latex (natural rubber), performed similarly, although the non-latex gloves had a greater impact on ozone depletion, mineral use and ionizing radiation. For climate change impact, sterile latex gloves were 11.6 times higher than non-sterile gloves. This study found that for both sterile type gloves (latex and non-latex), the manufacture of the gloves contributes to the most considerable environmental impact, with an average of 64.37% for sterile latex gloves and 60.48% for non-latex sterile gloves. Using the LCA methodology, this study quantitatively demonstrated the environmental impact of sterile versus non-sterile gloves.

Potential for significantly improving comprehensive performance of oil-well cement by a new type of latex

In this study, a new type of soap-free inorganic/organic composite latex (SBML-II) was prepared by soap-free emulsion polymerisation method using sodium p-styrenesulfonate (SSS) and modified silicon dioxide as copolymer emulsifiers, which were characterised by Fourier transform infrared spectrometer, transmission electron microscope, thermo-gravimetric analysis and other means. Then the latex was employed to prepare polymer latex modified oil-well cement, and the influence of the latex on the basic properties of cement slurry, mechanical properties and microstructure of cement matrix was evaluated. The characterisation of SBML-II showed that the synthesised latex presents a typical core-shell structure and possesses better dispersibility, stability and thermal stability than conventional latex (SBML-I). At the same time, the SBML-II latex forms a membranous morphology more easily than SBML-I at the same temperature and has better compatibility with additives and resistance to ions. Performance evaluation in cement slurry and cement matrix showed that the SBML-II has a good dilution effect on cement slurry and excellent potential to improve the mechanical properties of the cement matrix. Meanwhile, the addition of SBML-II is helpful to improve microstructure, owing to film formation in the cement matrix.

The investigation of optimum condition of natural rubber epoxidation reaction in latex phase

Natural rubber (NR) latex epoxidation is a chemical modifcation of natural rubber to produce natural rubber with higher polarity (oil resistant) which is commonly called epoxidized natural rubber (ENR). ENR is produced from the reaction of natural rubber latex with performic acid. Performic acid is formed from in situ reaction between formic acid and hydrogen peroxide. During epoxidation process, the carboxyl group of natural rubber is converted into epoxy group and various side reaction products such as carbonyl, hydroxyl, and hydro furan. These side products must be minimalized to optimize the epoxy level. The epoxidation reaction was carried out at 70 ° C for 6 hours using 2 types of latex: fresh latex (FL) and concentrated latex (CL). The addition of reactant was varied in two ways: dropwise (coded “1”) and poured all at once (coded “2”). The epoxy product and rate constant (k) were analyzed to obtain optimum reaction condition. The epoxy and side reaction content were determined by Attenuated Resonance Fourier Transform Infrared (ATR-FTIR). The slope of epoxy-time plotting curve was determined as ENR rate constant (k). The optimum NR epoxidation reaction was achieved in CL2, which exhibited lowest value of side reaction and highest value of k (2.8082x10 -5 L mol -1 sec -1 ).