Emulsion Graft Copolymerization Research Articles

The Effect of Silver Nanoparticles/Titanium Dioxide in Poly(acrylic acid-co-acrylamide)-Modified, Deproteinized, Natural Rubber Composites on Dye Removal.

This work aims to enhance the dye-removal performance of prepared poly(acrylic acid-co-acrylamide)-modified, deproteinized, natural rubber ((PAA-co-PAM)-DPNR) through incorporation with silver nanoparticles/titanium dioxide. The (PAA-co-PAM)-DPNR was prepared by emulsion-graft copolymerization with a grafting efficiency of 10.20 ± 2.33 to 54.26 ± 1.55%. The composites based on (PAA-co-PAM)-DPNR comprising silver nanoparticles and titanium dioxide ((PAA-co-PAM)-DPNR/Ag-TiO2) were then prepared by latex compounding using the fixed concentration of AgNO3 (0.5 phr) and varying concentrations of TiO2 at 1.0, 2.5, and 5.0 phr. The formation of silver nanoparticles was obtained by heat and applied pressure. The composites had a porous morphology as they allowed water to diffuse in their structure, allowing the high specific area to interact with dye molecules. The incorporation of silver nanoparticles/titanium dioxide improved the compressive modulus from 1.015 ± 0.062 to 2.283 ± 0.043 KPa. The (PAA-co-PAM)-DPNR/Ag-TiO2 composite with 5.0 phr of TiO2 had a maximum adsorption capacity of 206.42 mg/g, which increased by 2.02-fold compared to (PAA-co-PAM)-DPNR. The behavior of dye removal was assessed with the pseudo-second-order kinetic model and Langmuir isotherm adsorption model. These composites can maintain their removal efficiency above 90% for up to five cycles. Thus, these composites could have the potential for dye-removal applications.

Preparation of Crosslinked Poly(acrylic acid-co-acrylamide)-Grafted Deproteinized Natural Rubber/Silica Composites as Coating Materials for Controlled Release of Fertilizer.

The crosslinked poly(acrylic acid-co-acrylamide)-grafted deproteinized natural rubber/silica ((PAA-co-PAM)-DPNR/silica) composites were prepared and applied as coating materials for fertilizer in this work. The crosslinked (PAA-co-PAM)-DPNR was prepared via emulsion graft copolymerization in the presence of MBA as a crosslinking agent. The modified DPNR was mixed with various contents of silica (10 to 30 phr) to form the composites. The existence of crosslinked (PAA-co-PAM) after modification provided a water adsorption ability to DPNR. The swelling degree values of composites were found in the range of 2217.3 ± 182.0 to 8132.3 ± 483.8%. The addition of silica in the composites resulted in an improvement in mechanical properties. The crosslinked (PAA-co-PAM)-DPNR with 20 phr of silica increased its compressive strength and compressive modulus by 1.61 and 1.55 times compared to the unloaded silica sample, respectively. There was no breakage of samples after 80% compression strain. Potassium nitrate, a model fertilizer, was loaded into chitosan beads with a loading percentage of 40.55 ± 1.03% and then coated with the modified natural rubber/silica composites. The crosslinked (PAA-co-PAM)-DPNR/silica composites as the outer layers had the ability of holding water in their structure and retarded the release of fertilizer. These composites could be promising materials for controlled release and water retention that would have potential for agricultural application.

Ultrafine fully vulcanized natural rubber modified by graft-copolymerization with styrene and acrylonitrile monomers

This research aims to modify ultrafine fully vulcanized powdered natural rubber (UFPNR) prepared by emulsion graft-copolymerization with styrene (St) and acrylonitrile (AN) monomers onto deproteinized natural rubber (DPNR). The effects of monomers content and St/AN weight ratio on grafting efficiency and thermal stability of the developed DPNR-g-(PS-co-PAN) were investigated. The results showed that grafting efficiency was enhanced up to 86% with monomers content 15 phr and weight ratio St:AN 80:20. The obtained DPNR-g-(PS-co-PAN) was radiated by an electron beam at various doses, followed by a spray drying process to produce UFPNR. The obtained modified UFPNR particles irradiated at dose up to 300 kGy were relatively spherical with a particle size of approximately 4.4 µm. Furthermore, the degradation temperature of 5wt% loss (Td5) of UFPNR was found in the range of 349–356 °C. The results revealed that the modified UFPNR is suitable as a toughening filler for a broader spectrum of polymers.Graphical

Ultrafine fully vulcanized natural rubber modified by graft-copolymerization with syrene and acrylonitrile monomers

Natural rubber (NR) is known as one of the most important renewable agricultural resources in Thailand. To enhance the NR's value, development and utilization of NR in form of commercial product are necessary. Commercial product based on ultrafine fully vulcanized powdered rubber (UFPR) was widely used in numerous potential applications such as toughening filler or friction modifier in brake pads. However, to meet the required thermal stability of friction modifier in brake pads for replacing the synthetic rubber powder, the modification of NR by graft-copolymerization with styrene (ST) and acrylonitrile (AN) monomer and production into the powder form are promised related to a sustainable economic system. From the beginning, the grafting process of NR latex was prepared by emulsion graft-copolymerization with ST and AN monomers onto deproteinized natural rubber (DPNR). The results revealed that the grafting with ST/AN monomer content of 80/20 weight ratio possessed the monomer conversion and grafting efficiency as high as 71% and 63%, respectively. After that, the obtained DPNR-g-(PS-co-PAN) was radiated by an electron beam, followed by a spray drying process to produce ultrafine fully vulcanized powdered natural rubber (UFPNR-g-(PS-co-PAN)). The SEM micrographs showed that UFPNR particles are relatively spherical with a particle size of approximately 3.56 μm. Furthermore, thermal stability i.e., degradation temperature at 5 % weight loss (Td5) of the modified UFPNR was substantially improved from 334 to 350°C. The benefits of these advanced technologies give an obvious conclusion proved that the modified UFPNR is a good candidate for replacing a commercial synthetic powdered rubber and suitable for using as toughening filler in high performance polymer composite applications.

Mechanically activated starch magnetic microspheres for Cd(II) adsorption from aqueous solution

Magnetic starch microspheres (AAM-MSM) were synthesized via an inverse emulsion graft copolymerization by using mechanically activated cassava starch (MS) as a crude material, acrylic acid (AA) and acrylamide (AM) as graft copolymer monomers, and methyl methacrylate (MMA) as the dispersing agent and used as an adsorbent for the removal of Cd(II) ions from aqueous solution. Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) were used to characterize the AAM-MSM adsorbent. The results indicated that AA, AM, and MMA were grafted to the MS, and the Fe 3 O 4 nanoparticles were encapsulated in the AAM-MSM adsorbent microspheres. The adsorbent exhibited a smooth surface, uniform size, and good sphericity because of the addition of the MMA and provided more adsorption sites for the Cd(II) ions. The maximum adsorption capacity of Cd(II) on the AAM-MSM was 39.98 mg·g −1 . The adsorbents were superparamagnetic, and the saturation magnetization was 16.7 A·m 2 ·kg −1 . Additionally, the adsorption isotherms and kinetics of the adsorption process were further investigated. The process of Cd(II) ions adsorbed onto the AAM-MSM could be described more favorably by the pseudo-second-order kinetic and Langmuir isothermal adsorption models, which suggested that the chemical reaction process dominated the adsorption process for the Cd(II) and chemisorption was the rate-controlling step during the Cd(II) removal process.

A new route for synthesis of polyurethane vinyl acetate acrylate emulsions as binders for pigment printing of cotton fabrics

HEREIN, two polyurethane oligomers were successfully synthesized using a prepolymer mixing process. The prepolymers were synthesized based on the step-growth addition polymerization of polypropylene glycol, Methylene diphenyl diisocyanate and 2-hydroxyethyl methacrylate or 2-hydroxyethyl acrylate. Isopropanol was functioned as the isocyanate blocking agent. Thereafter, different terpolymer emulsions were prepared by the emulsion graft copolymerization with the vinyl acetate monomer in presence of 2-ethylhexyl acrylate as a vinyl monomer. The chemical structures of the synthesized oligomeric monomers were probed by FTIR spectroscopy and found to vary with the content of acrylic monomer used in the oligomer synthesis phase (i.e.hydroxyethyl acrylate or hydroxyethyl methacrylate). The topography, thermal stability, and particle size of terpolymers were investigated by SEM, TGA, and zeta potential, respectively. The TGA results demonstrated marked enhancement in thermal stability of the synthesized terpolymers up to ca. 600°C, which was concurrent with enhanced surface homogeneity and film properties as evidenced by the SEM images. These terpolymers showed also property enhancement as binders for textile pigment printing in terms of rubbing resistance, color strength and fastness to washing when compared to the commercial binders. These judgments would provide a new competent synthesis route by introducing polyurethane acetate vinyl acrylate as the binder for use in pigment printing of cotton fabrics.

Amphoteric Ion Exchange Membranes Prepared by Preirradiation-Induced Emulsion Graft Copolymerization for Vanadium Redox Flow Battery.

A series of poly(vinylidene difluoride)-based amphoteric ion exchange membranes (AIEMs) were prepared by preirradiation-induced graft copolymerization of styrene and dimethylaminoethyl methacrylate in an aqueous emulsion media followed by solution casting, sulfonation, and protonation. The effects of absorbed dose and comonomer concentration on grafting yield (GY) were investigated. The highest GY of 44.5% at a low comonomer concentration of 0.9 M could be achieved. FTIR, TGA, and X-ray photoelectron spectroscopy (XPS) confirmed the successful grafting and sulfonation of the as-prepared AIEMs. Properties of the AIEMs such as water uptake, ion exchange capacity (IEC), ionic conductivity, and crossover behavior of VO2+ ions prepared by this novel technique were systematically investigated and compared with those of the commercial Nafion 115 membrane. It was found that at a GY of 28.4%, the AIEMs showed higher IEC and conductivity, lower permeability of VO2+ ions, and a longer time to maintain open circuit voltage than Nafion 115, which was attributed to their high GY and elaborate amphoteric structure. Consequently, this work has paved the way for the development of green and low-cost AIEMs with good performance for vanadium redox flow battery applications.

Synthesis of Poly (Butadiene –g–Styrene) Core-Shell Latex for Use in Cement Modifying

Polybutadiene–graft –polystyrene (PB-g -PS) latex with different ratios of polybutadiene to polystyrene were prepared via emulsion graft copolymerization method through grafting styrene onto polybutadiene latex using a redox initiator system. The PB macroradicals reacted with styrene to form graft copolymers. The effect of initiator concentration, reaction temperature, grafting monomer/polybutadiene weight ratios, and monomer dropping time on the conversion, grafting efficiency, degree of grafting, and mean particle diameter of graft copolymerization reaction were investigated. The grafting efficiency of PB-g-PS was determined by a solvent-extraction technique. Fourier transform infrared spectroscopy and nuclear magnetic resonance technique were used to confirm structure of the synthesized copolymers. Transmission election micrographs verified that the synthesized latex particles had a core –shell structure, which can be incorporated into cement as modifier.

Facile Fabrication of N-Methyl-D-Glucamine Grafted HDPE Particle as Adsorbent for Boron Removal from Aqueous Solution

Glycidyl methacrylate (GMA) was grafted onto the surface of HDPE particles by radiation grafting and emulsion graft copolymerization. And subsequent ring-opening reaction of expoxy groups in poly-GMA graft chains with N-methylglucamine (NMG) was conducted to synthesis the boron adsorbent. The synthesis condition (radiation dose and NMG concentration) was optimized and characterized by IR and SEM. Adsorption behaviors of the boron adsorbent for boron removal presented that adsorption kinetics was well described by pseudo-second-order kinetic mode. The adsorption isothermal was well fitted with both Langmuir and Freundlich isotherm models. The adsorption capacity for boron reached 15.63 mg/g at optimal pH 8. Dynamic experiment revealed that boron could be efficiently adsorbed by the boron adsorbent and fully desorbed using 13 BV of 1 mol/L HCl.

Grafting Methyl Methacrylate onto Silk via Emulsion Graft Copolymerization Using a Diethylzinc Complex Initiator

Methyl methacrylate (MMA) was grafted onto silk fiber in a one-step emulsion system using a diethylzinc and 1,10-phenanthroline complex. The reaction conditions were investigated by varying temperature and initiator to monomer ratio. Fourier transform infrared (FTIR) spectrum, thermogravimetric analysis (TGA), and scanning electron microscopy (SEC) techniques were used to characterize the structure, thermal stability, and surface morphology of the obtained product, respectively. Grafting of MMA onto silk increased the thermal stability of silk. The FTIR spectrum and SEM images provided further evidence that MMA has been successfully grafted onto the silk fiber. A peak ascribed to the C=O stretching vibration of MMA was detected in the FTIR spectrum of grafted silk fiber, which was not present in the spectrum of pure silk fiber. Moreover, the SEM images illustrated the increase in diameter and surface roughness of grafted silk compared with pure silk. Lastly, the dyeing performance of the modified silk was significantly increased.

Poly(butyl acrylate-co-fluorinated acrylate)-graft-natural rubber: Synthesis and application as compatibilizer for natural rubber/poly(butyl acrylate-co-fluorinated acrylate) films

Poly(butyl acrylate-co-fluorinated acrylate)-graft-natural rubber was successfully prepared via emulsion graft copolymerization and applied as a compatibilizer for improving phase compatibility and toughness of natural rubber/poly(butyl acrylate-co-fluorinated acrylate) films. From graft copolymerization step, butyl acrylate (BA) acted as a co-monomer to be initially grafted onto the natural rubber (NR) and then copolymerized with 2,2,2–trifluoroethyl methacrylate (3FMA) to form a grafting poly(BA-co-3FMA) chain onto the NR backbone. The appropriated BA/3FMA ratio at 30/70 (w/w) provided the highest graft copolymer fraction of 72.8 wt% with 25.3 mol% grafted 3FMA and 68.5% grafting efficiency under center reaction condition. Transmission electron microscopy analysis indicated that the graft product had core-shell morphology, which NR was a core and covered by poly(BA-co-3FMA) shell. The results from Molau test and atomic force microscopy showed that the addition of 5–10 wt% graft product could enhance the compatibility between NR and poly(BA-co-3FMA) phases in the NR/poly(BA-co-3FMA) films (20/80 (w/w)) and provided the obtained films with a greater elongation at break to 266% than that of poly(BA-co-3FMA) film (27%). The compatibilized films also exhibited a high hydrophobicity (water contact angle = 109°) and oleophobicity (hexadecane contact angle = 54°) with a low surface energy (8.04 mN/m), which can be further applied as self-sealing films for moisture and oil protection.

Efektivitas karet alam termoplastik sebagai peningkat indeks viskositas minyak pelumas kendaraan

Diversification of rubber goods are highly needed to enhance natural rubber domestic consumption. One of the efforts is by using thermoplastic natural rubber that is synthesized from emulsion graft copolymerization of natural rubber latex with thermoplastic monomer as index viscosity improver of lubricating oil. The research aimed to study the effect of thermoplastic natural rubber (natural rubber–styrene copolymer) addition, at various concentration, into base paraffinic lube oil (HVI 60 and HVI 650) on index viscosity value of lubricating oil. The result showed that emulsion graft copolymerization at composition ratio of natural rubber to styrene monomer 85:15, at 65oC for 7 hours, with addition of 1% ammonium peroxidisulfate as initiator and 2% sodium dodecyl sulfate as surfactant produced thermoplastic natural rubber (TPNR, copoly NR-ST) with grafting efficiency of 56,48%. The TPNR can be functioned properly as index viscosity improver at 5% concentration to base paraffinic lube oil either HVI 60 or HVI 650. The obtaining new lubricating oils could fulfill the index viscosity standard requirement refered to Decree of Directorat General of Oil and Gas No 85K/34/DDJM/1998, and could compete with the commercial lubricating oil type 20W-50, 10W-40, and 15W-40.

Pengaruh Rasio Karet Alam Terdeproteinisasi dengan Monomer Vinil terhadap Karakteristik Karet Alam Termoplastik

<em>Chemical modification of natural rubber latex by emulsion graft copolymerization with thermoplastic monomer produces thermoplastic natural rubber (TPNR). Ratio composition of natural rubber to thermoplastic monomer determines the TPNR properties. TPNR has good mechanical properties of natural rubber and high processability of plastic material thus enhancing its application in industry. The research, which was conducted at research laboratory of Indonesian Rubber Research Institute, from June to December 2014, aimed to study the effect of the ratio of deproteinized natural rubber (DPNR) latex to vinyl monomer (VM: methyl methacrylate and styrene) on physical and mechanical properties of TPNR produced from batch graft copolymerization. Batch graft copolymerization was conducted at certain ratios of DPNR latex with methyl methacrylate and styrene </em><em>(70:30; 60:40; and 50:50) at (65°C, 5 hours), and subsequently at (70°C, 1 hour)</em>.<em> The result showed that batch technique tend to cause the formation of homopolymer vinyl which also affected the TPNR properties. Visually, the TPNR had white color, hard and brittle texture yet easier to process as shown by low time and energy consumption during compounding. The ratio of DPNR to VM at 70:30 was regarded as the optimum ratio for its balanced properties between elastomeric material of DPNR and thermoplastic material of VM.</em>

Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

Abstract Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments.

Study on Preparation under Microwave Radiation and Application of Chitosan Grafted Poly(acrylamide) Inverse Latex

Inverse emulsion graft copolymerization of chitosan and acrylamide monomer under microwave radiation was studied. It was shown that when the microwave radiation power was 300W, the microwave radiation time was 150S, the volume ratio of oil phase and water phase was 1:1, the weight ratio of chitosan and AM was 1:7, the initiator concentration was 0.67mmol/L, the dosage of emulsification agent was 7% of the weight of oil phase and the weight ratio of Span-80 and OP-10 was 6:4, stable inverse latex could be gained. A good dry strengthening effect had been obtained by applying the above mentioned latex in wheat straw pulp as the strengthening agent. The breaking length and tearing index of paper was respectively increased by 23.5% and 15.1% when the dosage of the graft copolymer latex was 0.6%.

The Properties and Morphology of Poly (Butadiene-Graft-Styrene) Latex Modified Mortars

Polybutadiene-graft-polystyrene (PB-g-PS) latex were prepared via emulsion graft copolymerization method. The weight ratios of polybutadiene to styrene ranged from 70/30, 50/50 to 30/70, then the PB-g-PS latex was used to modify cement mortar. This study examines the effects of core-shell ratios（c/s） on the typical properties and morphology of PB-g-PS latex modified mortars. The PB-g-PS latex modified cement mortar were prepared at different polymer-cement ratios（p/c）, and tested to obtain the water-cement ratios（w/c）, fluidity, water retention rate, flexural and compressive strengths. SEM was used to investigate the microstructure of polymer- modified mortars（PMMs）. On the basis of the test results, effect of the c/s and p/c on the typical properties and morphology of PMMs were discussed. It is concluded that PB-g-PS core-shell latex can be incorporated into cement as modifier.

Synthesis and properties of grafted latices from a soybean oil‐based waterborne polyurethane and acrylics

AbstractA novel soybean oil‐based vinyl‐containing waterborne polyurethane (VPU) dispersion has been successfully synthesized from toluene 2,4‐diisocyanate, dimethylol propionic acid and a 90 : 10 mixture of chlorinated soybean oil‐based polyol and acrylated epoxidized soybean oil (AESO). Then, a series of VPU/acrylic grafted latices have been prepared by emulsion graft copolymerization of acrylic monomers (40 wt % butyl acrylate and 60 wt % methyl methacrylate) in the presence of the VPU dispersion, using potassium persulfate as an initiator. The structure, morphology, and thermal and mechanical properties of the resulting latices, containing 15–60 wt % soybean oil‐based polyols as a renewable resource, have been investigated by Fourier transform infrared spectroscopy, solid state 13C NMR spectroscopy, transmission electron microscopy, thermogravimetric analysis, dynamic mechanical analysis, and mechanical testing. The results indicate that graft copolymerization of the acrylic monomers onto the VPU network occurs during emulsion polymerization, leading to a significant increase in the thermal stability and mechanical properties of the resulting miscible grafted latices. This work provides new environmentally‐friendly latices from a renewable resource with high performance for coating applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Heterogeneous emulsion graft polymerization of glycidyl methacrylate on a wood matrix

The studies allowed developing an accessible method of synthesis of a highly permeable α-oxide copolymer of wood by emulsion graft copolymerization with the reactive monomer glycidyl methacrylate and establishing the optimum conditions for conducting the process. In modification of a natural polymer with GMA with a concentration of 10% for 60 min at 80 °C in the presence of the Fe 2+ —H 2 O 2 initiating redox system with a 2.52 mg/g iron ion content of 0.017%, almost quantitative conversion of the monomer and a high degree of grafting efficacy was attained. The mass fraction of PGMA in the fibre phase is 88-90% and the EN is 19-21%.

Preparation of HPMC–EA–DMAEMA nanosized latex

Nanosized copolymer latex of hydroxypropylmethylcellulose (HPMC) grafted with ethyl acrylate (EA) and dimethylaminoethyl methacrylate (DMAEMA) has been prepared by acidifying submicron-sized latex particles synthesized by soap-free emulsion graft copolymerization using potassium persulfate (KPS) as initiator. The effects on the diameter of the latex particles of different conditions, for example concentration of DMAEMA, amount of HPMC, and ratio of HCl to DMAEMA for acidification, were investigated. It was found that increasing the mole ratio of HCl to DMAEMA to 1.0 and increasing the DMAEMA content both resulted in a decrease in particle diameter, whereas increasing the amount of HPMC resulted in larger particle sizes. Measurement by dynamic light scattering (DLS) revealed the diameter of the latex particles was >200 nm before acidification and <100 nm after acidification. Evidence of grafting was obtained by use of Fourier transform infrared (FTIR) spectroscopy. Transmission electron microscopy (TEM) was used to characterize the morphology of the copolymer particles before and after acidification.

γ‐Radiation–induced emulsion graft copolymerization of MMA onto jute fiber

AbstractGraft copolymerization of methyl methacrylate (MMA) onto jute substrate was carried out using gamma radiation (60Co) both by the preirradiation and “simultaneous irradiation and grafting” methods in an aqueous emulsion system. The variation of graft weight with radiation dose, intensity of radiation, and irradiation environment was investigated. In the case of the preirradiation method, irradiation in air produced up to 30% graft weight compared to only 20% obtained when the irradiation was conducted in nitrogen environment. In this method the graft copolymerization reaction was initiated by reactive species having different life times, some of which were very long. In simultaneous irradiation and grafting method, the graft weight passes through a maximum value (∼15%) with radiation dose and graft weight limited due to excessive homopolymerization. A comparative study on the mechanical properties of samples grafted by both preirradiation and simultaneous irradiation and grafting methods was carried out. The results showed that the method of grafting has significant influence on the mechanical properties of grafted jute. © 2002 Wiley Periodicals, Inc. Adv Polym Techn 21: 132–140, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/adv.10016