Studies of Natural Rubber Grafted with Acrylic Monomers

2010 ◽  
Vol 123-125 ◽  
pp. 1263-1266
Author(s):  
Suek Songprateepkul ◽  
Pranee Chumsamrong
Keyword(s):  
Natural Rubber ◽  
Graft Copolymerization ◽  
Monomer Conversion ◽  
Monomer Mixture ◽  
Nmr Spectrum ◽  
Grafting Efficiency ◽  
Weight Percentage ◽  
Grafting Reaction ◽  
Redox Initiator ◽  
Percentage Conversion

In order to increase polarity and widen application of natural rubber, the natural rubber (NR) was modified by graft copolymerization with methyl methacrylate (MMA) and glycidyl methacrylate (GMA). The grafting reaction was carried out using emulsion polymerization at 40°C. Redox initiator was used to initiate polymerization. Weight percentage ratio of MMA to GMA was firstly fixed at 90/10 in order to study the effects of amount of initiator and monomer mixture-to-rubber ratio on grafting efficiency [GE(%)] and percentage conversion of monomer (%conversion). The graft copolymerization condition that showed the highest grafting efficiency was chosen to study the effect of MMA-to-GMA ratio. It was found that the highest grafting efficiency [GE(%) = 85.11] were obtained when 1 part of NR, 0.75 part of monomer mixture and 1 phr of initiator were used. 1H-NMR spectrum of the graft copolymer with grafting efficiency of 85.11% illustrated that main monomer grafted onto NR chain was MMA. However, there was a signal of GMA that attached onto the NR chain. The results from an adjustment of MMA-to-GMA ratio showed that grafting efficiency tended to decrease with increasing the amount of GMA. On the other hand, an adjustment of MMA-to-GMA ratio did not significantly affect %conversion.

Graft Copolymerization of Acrylamide onto Activated Starch Using Inverse Emulsion Polymerization

2011 ◽  
Vol 308-310 ◽  
pp. 600-605
Author(s):  
Dian Mo Zheng ◽  
Sheng Gan Zhu ◽  
Li Ping Wu
Keyword(s):  
Ball Milling ◽  
Graft Copolymerization ◽  
Chemical Reactivity ◽  
Weight Ratio ◽  
Monomer Conversion ◽  
Ammonium Persulfate ◽  
Grafting Efficiency ◽  
Inverse Emulsion ◽  
Initiation System ◽  
Ft Ir

Activated starch was prepared by ball milling before used. Graft copolymerization of acrylamide onto activated starch was carried out in inverse emulsion using a redox initiation system of ammonium persulfate and sodium bisulfite. The effects of ball-milling time, reaction temperature, initiator concentration and weight ratio of acrylamide to starch on the conversion of monomer, grafting percentage and grafting efficiency were studied. The structure and properties of the graft copolymer and activated starch were characterized by FT-IR, XRD and SEM. The results showed that ball milling could progressively destroy the crystalline structure of starch and improve the chemical reactivity. The monomer conversion, grafting percentage and grafting efficiency of grate copolymerization were 96.6%、62.4%、85.49%, respectively.

scholarly journals Dynamic Mechanical Properties of Vietnam Modified Natural Rubber via Grafting with Styrene

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
T. A. Dung ◽  
N. T. Nhan ◽  
N. T. Thuong ◽  
D. Q. Viet ◽  
N. H. Tung ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Graft Copolymer ◽  
Graft Copolymerization ◽  
Dynamic Mechanical Properties ◽  
Dynamic Mechanical ◽  
Tert Butyl Hydroperoxide ◽  
Wide Range ◽  
Redox Initiator ◽  
Tetraethylene Pentamine

The dynamic mechanical behavior of modified deproteinized natural rubber (DPNR) prepared by graft copolymerization with various styrene contents was investigated at a wide range of temperatures. Graft copolymerization of styrene onto DPNR was performed in latex stage using tert-butyl hydroperoxide (TBHPO) and tetraethylene pentamine (TEPA) as redox initiator. The mechanical properties were measured by tensile test and the viscoelastic properties of the resulting graft copolymers at wide range of temperature and frequency were investigated. It was found that the tensile strength depends on the grafted polystyrene; meanwhile the dynamic mechanical properties of the modification of DPNR meaningfully improved with the increasing of both homopolystyrene and grafted polystyrene compared to DPNR. The dynamic mechanical properties of graft copolymer over a large time scale were studied by constructing the master curves. The value of bT has been used to prove the energetic and entropic elasticity of the graft copolymer.

scholarly journals Graft Copolymerization of Methyl Methacrylate and Vinyltriethoxysilane onto Natural Rubber

2021 ◽  
Vol 31 (4) ◽  
pp. 55-60
Keyword(s):  
Nmr Spectroscopy ◽  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Tensile Property ◽  
Graft Copolymer ◽  
Graft Copolymerization ◽  
Silica Particles ◽  
Grafting Efficiency

Preparation and characterization of natural rubber grafted with methyl methacrylate (MMA) and vinytriethoxysilane (VTES) were performed in the present work. Graft copolymerization of methyl methacryate was carried out in latex stage, and VTES was added during the graft copolymerization of MMA. FTIR and NMR spectroscopy were used to investigate the structure of graft copolymer and determination of conversion and grafting efficiency of MMA. It confirmed that the poly(methyl methacrylate) (PMMA) and silica particles (PVTES) were successfully formed in NR-graft-PMMA-PVTES graft copolymer. Conversions of MMA were about 90-100%; however, MMA grafting efficiency decreased as the MMA concentrations increased. Tensile property of NR-graft-PMMA-PVTES was found to improve compared with that of pure NR.

Effects of redox initiator on graft copolymerization of methyl methacrylate onto natural rubber

2006 ◽  
Vol 101 (4) ◽  
pp. 2587-2601 ◽  
Author(s):  
Teeranuch Kochthongrasamee ◽  
Pattarapan Prasassarakich ◽  
Suda Kiatkamjornwong
Keyword(s):  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Graft Copolymerization ◽  
Redox Initiator

Graft Copolymerization of Starch and Acrylamide Initiated by AIBN in Aqueous Two-Phase System

2011 ◽  
Vol 239-242 ◽  
pp. 1433-1436 ◽  
Author(s):  
Ya Feng Cao ◽  
Zao Li Liu ◽  
Yuan Li ◽  
Feng Zhi Tan
Keyword(s):  
Disperse System ◽  
Mass Fraction ◽  
Graft Copolymerization ◽  
Monomer Conversion ◽  
Phase System ◽  
Optimum Conditions ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Grafting Efficiency ◽  
Dissolution Property

In aqueous two-phase system, azodiisobutyronitrile（AIBN） was adsorbed on starch by dissolve- precipitate method. Free radical was then produced by its thermolysis, thus graft copolymerization of starch and acrylamide could be initiated. The effect of factors such as initiating system, organic solvent for AIBN dissolving, time for pre-initiation, concentration of initiator, composition and concentration of disperse system on monomer conversion, grafting efficiency, and dissolution property of the reaction product were studied. The optimum conditions of the reaction were as follows: AIBN was used as initiator and methanol as solvent; pre-initiation time was 25 min; concentration of AIBN was 2.6×10-4 mol/L; polyethylene glycol (PEG) and polyvinyl alcohol (PVA) was used as disperse system, the ratio of m(PEG):m(PVA) was 2.0:1 and their total mass fraction was 6.5%; both pre-initiation and polymerization temperatures were 60-65 °C. Monomer conversion (C) and grafting efficiency (GE) of the product obtained under these conditions were 99.4% and 99.1%, respectively.

Investigation of the effect of some variables on terpolymerization process of vinyl monomers in CSTR by design of experimental method

e-Polymers ◽  
2018 ◽  
Vol 18 (3) ◽  
pp. 257-266 ◽  
Author(s):  
Amin Moslemi ◽  
Rouhallah Bagheri ◽  
Negar Karami ◽  
Ehsan Mokhtari
Keyword(s):  
Intrinsic Viscosity ◽  
Monomer Conversion ◽  
Monomer Mixture ◽  
Continuous Stirred Tank Reactor ◽  
Optimum Conditions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Mixture Ratio ◽  
Redox Initiator ◽  
Initiator System

AbstractAqueous slurry free radical terpolymerization of acrylonitrile (AN) with vinyl acetate (VAc) and a constant amount of 2-acrylamido-2-methylpropane sulfunic acid (AMPS) using K2S2O8/NaHSO3 redox initiator was carried out in a 15-l continuous stirred tank reactor at constant temperature (60°C) and atmospheric pressure. A three-level response surface method based on central composite design was applied to investigate the effect of VAc concentration (wt%) in monomer mixture, bisulfite- to-persulfate ratio in redox initiator system $\left( {\frac{{{\text{[HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right)$ and bisulfite-to-monomer mixture ratio $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right)$ on the monomer conversion percentage to polymer, intrinsic viscosity [(η)] and sulfur end groups (SEG) index of the prepared polymers. Experimental results showed that the optimum conditions for synthesis of AN-VAc-AMPS system can be addressed as VAc=9 wt%, $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{[{{\text{S}}_2}{\text{O}}_8^{ - 2}]}}} \right) = 9.6$ and $\left( {\frac{{[{\text{HSO}}_3^ - ]}}{{{\text{AN}} + {\text{VAc}}}}} \right) = 0.027.$ Monomer conversion percentage to polymer, intrinsic viscosity and SEG index under optimum conditions were 75%, 1.38 dl/g and 190, respectively. The synthesized polymer under these optimum conditions can satisfy the requirements for acrylic fiber production in which its characterization was confirmed with Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analysis, X-ray diffraction, differential scanning calorimetry and scanning electron microscope.

Preparation of Graft Copolymer of Natural Rubber and Polystyrene by Electron Beam Irradiation

2014 ◽  
Vol 931-932 ◽  
pp. 73-77 ◽  
Author(s):  
Thammarit Khamplod ◽  
Surapich Loykulnant ◽  
C. Kongkaew ◽  
P. Prapainainar
Keyword(s):  
Electron Beam ◽  
Radiation Dose ◽  
Natural Rubber ◽  
Graft Copolymer ◽  
Crosslink Density ◽  
Electron Beam Irradiation ◽  
Graft Copolymerization ◽  
Monomer Conversion ◽  
Beam Irradiation ◽  
Ft Ir

The simultaneous graft copolymerization between natural rubber (NR) and styrene monomer (St) was induced by electron beam irradiation. The grafted polystyrene in graft copolymer was characterized by Fourier Transform Infrared Spectroscopy (FT-IR). This research investigated the influence of three factors (radiation dose, type of emulsifier and adding of sensitizer; normal butyl acrylate (n-BA)). It was found that the appropriated emulsifier was ammonium laurate which lead to higher monomer conversion and grafting efficiency. The adding of n-BA could notably enhance monomer conversion and crosslink density. Moreover increasing radiation dose, the monomer conversion and crosslink density increased. This technique was a cleaner and faster technology suitable for grafting application.

scholarly journals Synthesis of an Addition-Crosslinkable, Silicon-Modified Polyolefin via Reactive Extrusion Monitored by In-Line Raman Spectroscopy

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1246
Author(s):  
Steffen Ulitzsch ◽  
Tim Bäuerle ◽  
Mona Stefanakis ◽  
Marc Brecht ◽  
Thomas Chassé ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Performance ◽  
Process Analytical Technology ◽  
Statistical Design ◽  
Reactive Extrusion ◽  
Statistical Design Of Experiments ◽  
Grafting Efficiency ◽  
Grafting Reaction ◽  
Central Composite Experimental Design ◽  
Process Factors

We present the modification of ethylene-propylene rubber (EPM) with vinyltetra-methydisiloxane (VTMDS) via reactive extrusion to create a new silicone-based material with the potential for high-performance applications in the automotive, industrial and biomedical sectors. The radical-initiated modification is achieved with a peroxide catalyst starting the grafting reaction. The preparation process of the VTMDS-grafted EPM was systematically investigated using process analytical technology (in-line Raman spectroscopy) and the statistical design of experiments (DoE). By applying an orthogonal factorial array based on a face-centered central composite experimental design, the identification, quantification and mathematical modeling of the effects of the process factors on the grafting result were undertaken. Based on response surface models, process windows were defined that yield high grafting degrees and good grafting efficiency in terms of grafting agent utilization. To control the grafting process in terms of grafting degree and grafting efficiency, the chemical changes taking place during the modification procedure in the extruder were observed in real-time using a spectroscopic in-line Raman probe which was directly inserted into the extruder. Successful grafting of the EPM was validated in the final product by 1H-NMR and FTIR spectroscopy.

Graft copolymerization of methyl methacrylate and vinyltriethoxysilane binary monomers onto natural rubber

2021 ◽  
Vol 28 (7) ◽  
Author(s):  
Thuong Nghiem Thi ◽  
Ha Cao Hong ◽  
Yusof Nurul Hayati ◽  
Seiichi Kawahara
Keyword(s):  
Natural Rubber ◽  
Methyl Methacrylate ◽  
Graft Copolymerization

Effect of Deacetylation on Characterization of pH Stimulus Responsive Chitosan-Acrylamide Hydrogels Using Radiation

2014 ◽  
Vol 896 ◽  
pp. 292-295 ◽  
Author(s):  
Kris Tri Basuki ◽  
Deni Swantomo ◽  
Sigit ◽  
Kartini Megasari
Keyword(s):  
Electric Fields ◽  
Chemical Sensor ◽  
Graft Copolymerization ◽  
X Ray Diffraction ◽  
Grafting Efficiency ◽  
Sensor Material ◽  
Swelling Degree ◽  
Gel Fraction ◽  
Stimulus Responsive ◽  
Acetyl Group

Smart hydrogels which can change their swelling behavior and other properties in response to environmental stimuli such as temperature, pH, solvent composition and electric fields, have attracted great interest as chemical sensor material and controlled release system. The pH stimulus responsive hydrogels were synthesized by gamma-irradiation graft copolymerization of chitosan-acrylamide. In this research the influence of deacetylation process on the hydrogels characterization were investigated by measuring grafting efficiency, gel fraction, swelling degree, and crosslink density. Evidence of grafting was confirmed by FTIR spectroscopy. X-ray diffraction showed reduction in the crystallinity of chitosan with different deacetylation process also after the graft copolymerization reaction. The results showed that decreasing acetyl group of chitosan increase the grafting efficiency, gel fraction and swelling degree. While crystallinity decreased. The hydrogels indicated pH-dependent swelling behaviour.

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