DETERMINATION OF A SUITABLE CONDITION OF GRAFT COPOLYMERIZATION OF VINYLTRIETHOXYSILANE ONTO NR TO FORM NANOMATRIX STRUCTURE

2018 ◽  
Vol 91 (4) ◽  
pp. 767-775 ◽  
Author(s):  
Yuanbing Zhou ◽  
Yoshimasa Yamamoto ◽  
Seiichi Kawahara
Keyword(s):  
Silica Nanoparticles ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Minor Component ◽  
Suitable Condition ◽  
Average Diameter ◽  
Silica Matrix ◽  
Rubber Particles ◽  
Hydrolysis And Condensation ◽  
Nanomatrix Structure

ABSTRACT Graft copolymerization of vinyltriethoxysilane (VTES) onto NR particles in the latex stage is a unique reaction, since it occurs together with hydrolysis and condensation of the triethoxysilane group of VTES to form a colloidal silica linking to the rubber particles. These reactions may contribute to the formation of a silica nanomatrix structure that consists of a dispersoid of rubber particles as the major component and a silica matrix as the minor component. Here, the graft copolymerization of VTES followed by hydrolysis and condensation is investigated to determine a suitable condition to prepare NR with a silica nanomatrix structure. The mechanical properties of the resulting graft copolymer are discussed in relation to the morphology, silica content, and gel content of the rubber. Based on morphological observations, NR particles with an average diameter of approximately 1 μm are well dispersed in a nanomatrix consisting of silica nanoparticles. The thickness of the silica nanomatrix increases as the monomer concentration increases, and a long incubation time generates large silica nanoparticles. The tensile strength and viscoelastic properties are significantly improved by forming the silica nanomatrix structure, with its continuous structure that prevents the NR particles from merging.

NANOMATRIX STRUCTURE FORMED BY GRAFT COPOLYMERIZATION OF STYRENE ONTO FRESH NATURAL RUBBER

2015 ◽  
Vol 88 (1) ◽  
pp. 117-124 ◽  
Author(s):  
L. Fukuhara ◽  
N. Kado ◽  
N. T. Thuong ◽  
S. Loykulant ◽  
K. Suchiva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
1H Nmr Spectroscopy ◽  
Graft Copolymerization ◽  
Suitable Condition ◽  
Transmission Electron ◽  
Tert Butyl Hydroperoxide ◽  
Polystyrene Matrix ◽  
Rubber Particles ◽  
Nanomatrix Structure

ABSTRACT Fresh NR was adopted to prepare rubber with a nanomatrix structure. The nanomatrix structure was formed by graft-copolymerization of styrene onto deproteinized fresh NR (fresh DPNR) in the latex stage using tert-butyl hydroperoxide/tetraethylenepentamine as an initiator. Graft-copolymer consisting of fresh DPNR and polystyrene (fresh DPNR-graft-PS) was characterized by 1H-NMR spectroscopy and transmission electron microscopy. Under a suitable condition of the graft-copolymerization, conversion and grafting efficiency of styrene was 98 and 80 mol%, respectively. Morphology of fresh DPNR-graft-PS was observed by transmission electron microscopy. The rubber particles of about 1 μm in diameter were found to be dispersed in polystyrene matrix of 10–30 nm in thickness. Tensile properties of fresh DPNR were dramatically improved by forming the nanomatrix structure, compared with DPNR.

Imprinting of protein over silica nanoparticles via surface graft copolymerization using low monomer concentration

2010 ◽  
Vol 26 (2) ◽  
pp. 760-765 ◽  
Author(s):  
Hongyan He ◽  
Guoqi Fu ◽  
Yan Wang ◽  
Zhihua Chai ◽  
Yizhe Jiang ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Surface Graft

scholarly journals New Grafted Copolymers Carrying Betaine Units Based on Gellan and N-Vinylimidazole as Precursors for Design of Drug Delivery Systems

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5451
Author(s):  
Stefania Racovita ◽  
Nicolae Baranov ◽  
Ana Maria Macsim ◽  
Catalina Lionte ◽  
Corina Cheptea ◽  
...  
Keyword(s):  
Graft Copolymerization ◽  
Polymer Concentration ◽  
Monomer Concentration ◽  
Ammonium Persulfate ◽  
Nitrogen Atmosphere ◽  
Sustained Drug Release ◽  
Reaction Conditions ◽  
Grafted Polymer ◽  
Grafted Copolymer ◽  
Grafting Reaction

New grafted copolymers possessing structural units of 1-vinyl-3-(1-carboxymethyl) imidazolium betaine were obtained by graft copolymerization of N-vinylimidazole onto gellan gum followed by the polymer-analogous reactions on grafted polymer with the highest grafting percentage using sodium chloroacetate as the betainization agent. The grafted copolymers were prepared using ammonium persulfate/N,N,N′,N′ tetramethylethylenediamine in a nitrogen atmosphere. The grafting reaction conditions were optimized by changing one of the following reaction parameters: initiator concentration, monomer concentration, polymer concentration, reaction time or temperature, while the other parameters remained constant. The highest grafting yield was obtained under the following reaction conditions: ci = 0.08 mol/L, cm = 0.8 mol/L, cp = 8 g/L, tr = 4 h and T = 50 °C. The kinetics of the graft copolymerization of N-vinylimidazole onto gellan was discussed and a suitable reaction mechanism was proposed. The evidence of the grafting reaction was confirmed through FTIR spectroscopy, X-ray diffraction, 1H-NMR spectroscopy and scanning electron microscopy. The grafted copolymer with betaine structure was obtained by a nucleophilic substitution reaction where the betainization agent was sodium chloroacetate. Preliminary results prove the ability of the grafted copolymers to bind amphoteric drugs (cefotaxime) and, therefore, the possibility of developing the new sustained drug release systems.

Multi-stable fluorescent silica nanoparticles obtained from in situ doping with aggregation-induced emission molecules

2015 ◽  
Vol 3 (45) ◽  
pp. 8775-8781 ◽  
Author(s):  
Yi-Feng Wang ◽  
Jing Che ◽  
Yong-Chao Zheng ◽  
Yuan-Yuan Zhao ◽  
Fei Chen ◽  
...  
Keyword(s):  
Silica Nanoparticles ◽  
Gastric Fluid ◽  
Silica Matrix ◽  
Simulated Gastric Fluid ◽  
Aggregation Induced Emission ◽  
Fluorescent Silica Nanoparticles ◽  
Photo Stability

Rigid structures provided by silica matrix restrict the intramolecular rotations of AIE molecules, and fluorescence of CWQ-11@SiO2 nanoparticles maintains excellent pH-, viscosity- and photo-stability, especially stable in simulated gastric fluid.

Preparation and Characterization of Cu-SiO2 Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 255-258 ◽  
Author(s):  
Young Hwan Kim ◽  
Beong Gi Jo ◽  
Jee Hean Jeong ◽  
Young Soo Kang
Keyword(s):  
Silica Nanoparticles ◽  
Room Temperature ◽  
Sio2 Nanoparticles ◽  
Hybrid Structures ◽  
Cu Nanoparticles ◽  
Stöber Method ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrolysis And Condensation

A room temperature route for doping silica particles with Cu nanoparticles to achieve hybrid structures is introduced. First, silica nanoparticles were synthesized according to the well-known Stöber method by hydrolysis and condensation of TEOS in a mixture of ethanol with water, using ammonia as catalyst to initiate the reaction. These SiO2 nanoaprticles were dried at 100 oC. We measured the size of these nanoparticles with transmission electron microscopy (TEM). Second, Cu-SiO2 nanoparticles were synthesized by reaction with CuCl2 and SiO2 nanoparticles in presence of catalyst at room temperature for 12 hrs. Results show silica nanoparticles of about 70 nm size with regularly deposited Cu nanoparticles. Cu-SiO2 nanoparticles were investigated with TEM images, energy dispersive X-ray analysis (EDX) spectrum and so on.

Influence of Reaction Conditions on the Properties of Nano-matrix Structure Formed by Graft-Copolymerization of Acrylonitrile onto Natural Rubber

2013 ◽  
Vol 844 ◽  
pp. 365-368 ◽  
Author(s):  
Kontapond Prukkaewkanjana ◽  
Seiichi Kawahara ◽  
Jitladda Sakdapipanich
Keyword(s):  
Mechanical Properties ◽  
Natural Rubber ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Matrix Structure ◽  
Oil Resistance ◽  
Wide Range ◽  
Initial Monomer

Natural rubber (NR) is one of the most important agriculture products of Thailand, which is an important material with unique and special characteristics used in wide range of applications such as mechanical properties, excellent strength, and elasticity. However, it is inferior in oil resistance due to the presence of hydrogen and carbon in its structure. This inherent drawback of NR has limited its application in industry. In order to expand the use of NR, this research is interested to improve the oil resistance of NR without loss of outstanding properties by grafting NR with acrylonitrile (AN) monomer to form the nano-matrix structure. The influences of the initial monomer concentration and initial initiator concentration were investigated. These effects on structure, mechanical properties and oil resistance properties were studied by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, tensile machine, and swelling in toluene, respectively. It was found that the tensile strength and oil resistance properties of graft copolymerization of AN onto NR increased with increasing the percentage grafting efficiency of acrylonitrile monomer.

Preparation of polyethylene-g-(polyacrylic acid) and its sodium salt ionomer by in-situ chlorinating graft copolymerization

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhi-Qiang Zhao ◽  
Shuang-Shuang Wang ◽  
Na Wang ◽  
Ji-Ruo Zhao ◽  
Ying Feng
Keyword(s):  
Acrylic Acid ◽  
Graft Copolymer ◽  
Sodium Salt ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Gel Permeation Chromatography ◽  
Reaction Process ◽  
Side Reactions ◽  
Chlorinated Polyethylene

AbstractAcrylic acid (AA) was grafted firstly onto high density polyethylene (HDPE) by in-situ chlorinating graft copolymerization (ISCGC), so a graft copolymer composed of chlorinated polyethylene (CPE) as backbone and poly (acrylic acid) (PAA) as branched chains was synthesized. And subsequently the preparation of its carboxylated ionmers was studied. This work was focused on discussing the reaction process for grafting AA onto HDPE by ISCGC and the preparing of carboxylated ionmers of CPE. In this paper, the structure of graft copolymer and the ionomer were characterized mainly by FT-IR, gel permeation chromatography (GPC) and graft degree (GD). The influence factors which related to the main and side reactions, including the monomer concentration, chlorine contents of the product, and reaction temperature were investigated. Additionally, effects of these factors on reaction process controlling were described. The aim of above is to investigate how CPE-cg-PAA and its sodium-salt ionomer were prepared.

Encapsulation of silica nanoparticles by poly(methyl methacrylate-co-styrene) via emulsion polymerization using dimethylaminoethyl methacrylate

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Mohammad Barari ◽  
Naser Sharifi-Sanjani
Keyword(s):  
Methyl Methacrylate ◽  
Silica Nanoparticles ◽  
Emulsion Polymerization ◽  
Monomer Concentration ◽  
Molar Ratio ◽  
Average Particle ◽  
Scanning Calorimetry ◽  
Potential Measurement ◽  
Emulsion Copolymerization ◽  
Dimethylaminoethyl Methacrylate

AbstractEncapsulation of silica nanoparticles was performed by emulsion copolymerization of methyl methacrylate (MMA) and styrene (St) using dimethylaminoethyl methacrylate (DM) as an auxiliary monomer. The emulsion polymerization was performed in the presence of silica nanoparticles as the seed to obtain encapsulated silica nanoparticles with polymer content and average particle sizes ranged from 35 wt. % to 85 wt. % and 114 to 272 nm respectively. Electrostatic attraction between anionic surface of silica beads and cationic amino groups of DM is the main driving force for the encapsulation of the silica nanoparticles. The influence of MMA, St and DM concentration on the coating of the silica nanoparticles was studied. It was demonstrated that DM has an important role in stabilizing the system. Transmission electron microscopy showed that coreshell structures with silica particles as core were coated with the polymer, of which the amount and morphology were influenced by the total monomer concentration and molar ratio of MMA to St. Zeta potential measurement confirmed the presence of DM on the surface of composite particles. Thermogravimetric analysis showed that the incorporation of silica in polymer matrix results in an enhancement of thermal stability in the encapsulated products. Differential scanning calorimetry studies indicated that the glass transition temperature of encapsulated particles can be either higher or lower than those of the pure terpolymer counterpart, depending on the DM content of the polymer shell. The products were also characterized by FT-IR spectroscopy.

Grafting of Methyl Acrylate and Methyl Methacrylate onto Jute fiber: Physico-Chemical Characteristics of the Grafted Jute

2013 ◽  
Vol 8 (3) ◽  
pp. 155892501300800 ◽  
Author(s):  
Ibrahim H. Mondal
Keyword(s):  
Methyl Methacrylate ◽  
Methyl Acrylate ◽  
Graft Copolymerization ◽  
Monomer Concentration ◽  
Redox System ◽  
Jute Fiber ◽  
Lower Amount ◽  
Physico Chemical ◽  
Dye Absorption ◽  
Graft Yield

The graft copolymerization of methyl acrylate and methyl methacrylate vinyl monomers onto jute fiber using potassium persulfate and ferrous sulfate redox system was investigated in an aqueous medium. Optimized reaction conditions for the graft copolymerization were established for parameter variables, of monomer concentration, initiator concentration, catalyst concentration, reaction time, and reaction temperature. The grafting degrees were found to depend on the above mentioned variables. A maximum graft yield of 17.3% for MA and 19.4% for MMA was obtained under effective optimized conditions for grafting. The attachment of the monomer on the grafted fiber was confirmed by FTIR studies. Dyeing was affected by monomer characteristics, and due to the development of hydrophobic nature on jute fiber by grafting, a lower amount of dye absorption occurred. Grafting has a favorable influence on tenacity, color fastness, and other properties of jute fiber.

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