Graft Polymerization Of Vinyl Acetate Research Articles

Starch Stabilized Polyvinyl Acetate Emulsion: Review

The Increasing global energy crisis and scarcity of petroleum resources has shifted the focus of the hemical industries to look for alternative raw material resources. The main focus of raw materials in wood adhesives, such as petroleum and natural gas [1,2], would be gradually replaced by renewable bio-resource polymers. Starch is a relatively an inexpensive and renewable product from abundant plants, easy processing and it has been extensively used as paper binders, sizing materials, glues and pastes [3], but its bonding capacity is not strong enough to glue substrate like wood, paper. Conventionally available wood adhesive emulsions are colloid like polyvinyl alcohol stabilized. A new research on biodegradable, renewable, environmentally friendly starch stabilized polyvinyl acetate emulsion that was synthesized by the graft polymerization of vinyl acetate onto starch. In this paper, we reviewed starch as colloid for synthesis of polyvinyl acetate emulsion.

Radiation induced graft polymerization of multi-walled carbon nanotubes for superhydrophobic composite membrane preparation

Highly soluble multi-walled carbon nanotubes (MWNTs) were prepared by radiation-induced free radical graft polymerization of vinyl acetate (VAc) onto pristine MWNT surfaces. High resolution transmission electron microscopy (HR-TEM), Fourier transform infrared (FTIR) spectroscopy, and micro-Raman spectroscopy were used to confirm that poly(vinyl acetate) (PVAc) had been successfully grafted onto the surface of the MWNTs. The effects of experimental parameters on the degree of grafting (DG) of PVAc were also investigated, including adsorbed dose, dose rate, initial monomer concentration, and solvents. The grafted MWNTs (MWNTs-g-PVAc) exhibited good solubility in common organic solvents at high mass fraction. In addition, a superhydrophobic composite membrane could be readily fabricated by vacuum filtration of MWNTs-g-PVAc onto a supporting membrane, as was confirmed by water contact angle testing and visualization by scanning electron microscopy.

Preparation of Functional Grafted Particles PVA/SiO2 with High Grafting Degree and Preliminary Research of Their Adsorption Character

Micro-sized silica gel particles were surface-modified with coupling agent γ-Aminopropyltrimethoxysilane (AMPS), obtaining the modified particles AMPS-SiO2, on which primary amino groups were chemically attached. Distilled water and DMSO were used as mixed solvents, and a redox initiation system was constituted with the amino groups on the surfaces of AMPS-SiO2 particles and ammonium persulphate in a solution. This practice realized the surface-initiated graft-polymerization of vinyl acetate (VAc), and prepared the grafted particles PVAc/SiO2 with a high grafting degree (about 32 g/100 g) of PVAc. PVAc can be transformed into PVA by the alcoholysis reaction, which results in functional grafted particles PVA/SiO2 with high grafting degree. The grafted particles PVAc/SiO2 were characterized by FTIR, SEM and TGA. The effects of main factors on the graft-polymerization of vinyl acetate were investigated emphatically, and their adsorption character was preliminarily explored. The experimental results show that the mixed solvents composed of water and DMSO along with a redox initiation system constituted with the amino groups on the surfaces of AMPS-SiO2 particles and ammonium persulphate in a solution realize highly effective surface-initiated graft-polymerization of vinyl acetate which is an oil-soluble monomer. By virtue of the hydrogen bonding interaction, the particles PVA/SiO2 can produce strong adsorption ability for pirimicarb and terbuthylazine which are nitrogenous organic molecules. Relying on the strong coordination chelating action, the particles PVA/SiO2 exhibit strong adsorption ability towards heavy metal ions.

Synthesis of copolymer grafts containing sulfoalkyl and hydrophilic groups in polymer electrolyte membranes

Proton exchange type polymer electrolyte membranes (PEM) consisting of ion conducting alkylsulfonic acid and hydrophilic groups such as a hydroxyl group were successfully synthesized by radiation-induced graft polymerization of vinyl acetate (VAc) into a poly(ethylene-co-tetrafluoroethylene) (ETFE) film, followed by saponification and alkylsulfonation with 1,3-propanesulfone. In contrast to the typical SN2 reactions in a solution, the base-catalyzed nucleophilic ring-opening reactions of hydroxyl groups of poly(vinylalcohol) grafts with 1,3-propanesultone in solid state ETFE films hardly proceeds in the hydrophilic solvents, but it does proceed in hydrophobic toluene with a weak base (triethylamine) to yield ETFE-grafted poly(vinylalcohol-co-vinylsulfopropyl ether) (PEM–OH) with various values of ion-exchange capacity (IEC) and molar ratio of hydroxyl to sulfo groups in the grafts. The relative-humidity (RH) dependence of the proton conductivity of the sulfonated membrane was compared with that of poly(styrenesulfonic acid)-grafted ETFE (PEM–PSSA) with a similar IEC (∼1.3 mmol g−1) at 80 °C. The PEM–OH showed a conductivity of 1.0×10−3 S cm−1 under 30% RH, which is higher than those of PEM–PSSA. Further, the PEM–OH with higher IEC (1.9 mmol g−1) prepared with a grafting degree of 82% and a sulfonation degree of 41% showed 3.8×10−3 S cm−1 under 30% RH at 80 °C. The conductivity is higher than that of PEMs based on sulfonated polyimide and poly(ether sulfone) with a similar IEC. Furthermore, the tensile strength of PEM–OH was 48 MPa with the elongation at break of 422%, which are better than those of Nafion. These results strongly indicate that the radiation-grafted PEM with hydroxyl groups is a promising material with excellent mechanical and electrochemical properties, which are important characteristics for a fuel cell operating at a high temperature and low humidity.

Graft Polymerization of Vinyl Acetate onto Potato Starch Dissolved in an Alkaline Solution

AbstractGraft polymerization of vinyl acetate (VAc) onto gelatinized and dissolved granular potato starch has been carried out using an initiation system of ceric ammonium nitrate (CAN)/nitric acid (HNO3) at 50°C. The granular starch was dissolved in an aqueous alkaline solution (0.25 M NaOH) for 24 h before graft reaction. The effects of reaction variables, such as the concentrations of acid, monomer, and initiator, on the grafting parameters of prepared starch/VAc copolymers have been investigated in both grafting methods for comparison. Although the scanning electron microscopy (SEM) images showed a rather similar homogeneous structure for dissolved and gelatinized starch, a higher grafting level, especially at lower monomer concentrations, was obtained for the copolymers prepared using the dissolved starch. A larger number of reactive sites uniformly created on the starch molecules led to greater accessibility of the monomer and improved considerably the grafting efficiency in the grafting conditions using the dissolved starch. The effects of the grafting methods on the microstructure, morphology, and thermal stability of the resulting copolymers have been studied by Fourier‐transform infrared (FTIR) spectroscopy, scanning electron microscopy, and thermogravimetric analysis (TGA), respectively. The TGA results showed that the grafting of VAc onto dissolved starch led to the formation of more thermally stable graft copolymers.

Macromol. React. Eng. 4/2008

Cover: The graft polymerization of vinyl acetate (VAc) from poly(ethylene glycol) (PEG) was investigated by both experiments and modeling work. The graph on the left of the cover picture illustrates the graft copolymer molecular weight as determined by definitive calculation, GPC with PVAc or PEG calibration, and the model prediction. Using the correlated Arrhenius expression of the chain transfer constant to PEG(CPEG), the graft copolymer molecular weights at various temperatures was predicted in the figure on the right. Further details can be found in the article by X. Zhu, B.-G. Li,* L. Wu, Y. Zheng, S. Zhu,* K.-D. Hungenberg, S. Müssig, and B. Reinhard on page 321.

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.

Graft polymerization of vinyl acetate onto granular starch: Comparison on the potassium persulfate and ceric ammonium nitrate initiated system

AbstractThis work was undertaken to discuss in depth the vital differences in the morphological development during synthesis, and properties of starch‐g‐poly‐(vinyl acetate) copolymers using two different initiators, potassium persulfate (KPS) and ceric ammonium nitrate (CAN). KPS‐initiated system gave relatively low values of grafting ratio and grafting efficiency, indicating a great tendency for the formation of poly(vinyl acetate) homopolymer (PVAc). Yet, higher values were seen for the CAN‐initiated system. Transmission electron microscope observations indicated a relatively broad distribution of latex particles for the KPS‐initiated system. The surface potential of latex particles was about −3.5 mV, which turned out to be insufficient to maintain stability of latex particles. On the other hand, a uniform particle size distribution was found for the CAN‐initiated system, as the surface potential of latex particles was 21.5 mV. Moreover, radicals on starch molecules were generated directly through a redox reaction with positively charged ceric ion. The hydrophobic PVAc chains were thus grafted on starch, resulting in an amphiphilic graft copolymer, which provides a sufficient stabilization degree as a role of surfactant to render a relatively uniform distribution of latex particles. The synthesized starch‐g‐poly(vinyl acetate) copolymers were further converted to starch‐g‐poly(vinyl alcohol) through saponification, which were subjected to evaluations regarding the biodegradation and cell culture capability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3017–3027, 2006

Removal of methyl tert-butyl ether from water by pervaporation using ceramic-supported polymer membranes

Pervaporation removal of methyl tert-butyl ether (MTBE) from dilute aqueous solutions was demonstrated using ceramic-supported polymer (CSP) membranes. These membranes were created by the free radical graft polymerization of vinyl acetate onto a vinyl trimethoxysilane-activated porous silica substrate having a native average pore size of 500 Å. The resulting membranes consisted of poly(vinyl acetate) chains terminally and covalently anchored to the membrane surface. These pervaporation membranes performed with separation factors ranging from about 68 to 577 at total permeate fluxes of 0.31–0.70 kg/m 2 h over feed concentrations of 74–7400 ppm (0.01–1%, v/v). MTBE flux was controlled by the feed-side concentration boundary layer, while water permeation was controlled by the membrane resistance. The primary effect of the grafted PVAc in these CSP membranes was to increase separation by rejecting water, as opposed to increasing the flux of MTBE.

Effect of Allyl Substitution in Chitosan on the Structure of Graft Copolymers

The kinetics of graft polymerization of vinyl acetate on allyl chitosan samples with varied content of allyl groups, initiated with ammonium peroxodisulfate, was studied.

Graft polymerization of vinyl acetate onto silica

AbstractThe free‐radical graft polymerization of vinyl acetate onto nonporous silica particles was studied experimentally. The grafting procedure consisted of surface activation with vinyltrimethoxysilane, followed by free‐radical graft polymerization of vinyl acetate in ethyl acetate with 2,2′‐azobis(2,4‐dimethylpentanenitrile) initiator. Initial monomer concentration was varied from 10 to 40% by volume and the reaction was spanned from 50 to 70°C. The resulting grafted polymer, which was stable over a wide range of pH levels, consisted of polymer chains that are terminally and covalently bonded to the silica substrate. The experimental polymerization rate order, with respect to monomer concentration, ranged from 1.61 to 2.00, consistent with the kinetic order for the high polymerization regime. The corresponding rate order for polymer grafting varied from 1.24 to 1.43. The polymer graft yield increased with both initial monomer concentration and reaction temperature, and the polymer‐grafted surface became more hydrophobic with increasing polymer graft yield. The present study suggests that a denser grafted polymer phase of shorter chains was created upon increasing temperature. On the other hand, both polymer chain length and polymer graft density increased with initial monomer concentration. Atomic force microscopy–determined topology of the polymer‐grafted surface revealed a distribution of surface clusters and surface elevations consistent with the expected broad molecular‐weight distribution for free‐radical polymerization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 300–310, 2003

Synthesis of Poly(Vinyl Acetate) - Chitin Graft Copolymers as a Base for Chitosan-Polyf(Vinyl Alcohol) Ion Exchangers

Graft polymerization of vinyl acetate with chitin was effected using either the ferrous ion/hydrogen peroxide redox system or gamma radiation for initiation. The polymerization reaction was studied with respect to graft yield, homopolymer yield and total conversion. Results imply that the redox initiation is superior to irradiation, since it gives a much higher graft yield. Conversion of chitin-g-poly (vinyl acetate) to chitosan-g-poly (vinyl alcohol) was expedited using 48% sodium hydroxide at 130°C for 3 h. The use of chitosan-g-poly (vinyl alcohol) as an ion-exchanger was examined. The capacity of this ion exchanger to adsorb heavy metal ions such as cupric and dichromate, as well as some dyestuffs was also studied. The results indicate that the copolymer under investigation is a potentially powerful ion exchanger that can be employed for heavy metals and dyestuff removal from wastewater effluents.

Synthesis of Poly(Vinyl Acetate) - Chitin Graft Copolymers as a Base for Chitosan-Polyf(Vinyl Alcohol) Ion Exchangers

Graft polymerization of vinyl acetate with chitin was effected using either the ferrous ion/hydrogen peroxide redox system or gamma radiation for initiation. The polymerization reaction was studied with respect to graft yield, homopolymer yield and total conversion. Results imply that the redox initiation is superior to irradiation, since it gives a much higher graft yield. Conversion of chitin-g-poly (vinyl acetate) to chitosan-g-poly (vinyl alcohol) was expedited using 48% sodium hydroxide at 130°C for 3 h. The use of chitosan-g-poly (vinyl alcohol) as an ion-exchanger was examined. The capacity of this ion exchanger to adsorb heavy metal ions such as cupric and dichromate, as well as some dyestuffs was also studied. The results indicate that the copolymer under investigation is a potentially powerful ion exchanger that can be employed for heavy metals and dyestuff removal from wastewater effluents.

ポリエピクロロヒドリンへの極性モノマーのグラフト重合による帯電防止効果

Hydrophilic elastomers were synthesized by the graft polymerization of vinylacetate or methacrylic acid onto poly (epichlorohydrin), and the effect of polymerization conditions on the grafting behavior was examined. Poly (vinylacetate) as graft chain was converted to poly (vinylalcohol) by hydrolysis of the graft polymers. Each electrical resistance of the graft polymers was measured. It was found that the surface resistivity of the graft polymers decreased with increasing the contents of the hydrophilic graft chains.

Graft polymerization of vinyl acetate onto silica

AbstractA method is reported for the surface grafting of polyvinyl acetate (PVAc) onto modified, nonporous silica. The silica surface was modified by silylation with vinyl(triethoxy) silane followed by graft polymerization of vinyl acetate. The graft yield was measured by thermogravimetric analysis and the monomer conversion was monitored by UV spectral analysis. The rate of the graft polymerization and the graft yield were proportional to the initial monomer concentration. Vinyl acetate conversion followed first‐order kinetics and displayed a trend of increasing initial rate with increasing monomer concentration.

Graft polymerization of vinyl acetate onto starch. Saponification to starch–g–poly(vinyl alcohol)

AbstractGraft polymerizations of vinyl acetate onto granular corn starch were initiated by cobalt‐60 irradiation of starch‐monomer‐water mixtures, and ungrafted poly(vinylacetate) was separated from the graft copolymer by benzene extraction. Conversions of monomer to polymer were quantitative at a radiation dose of 1.0 Mrad. However, over half of the polymer was present as ungrafted poly‐(vinyl acetate) (grafting efficiency less than 50%), and the graft copolymer contained only 34% grafted synthetic polymer (34% add‐on). Lower irradiation doses produced lower conversions of monomer to polymer and gave graft copolymers with lower % add‐on. Addition of minor amounts of acrylamide, methyl acrylate, and methacrylic acid as comonomers produced only small increases in % add‐on and grafting efficiency. However, grafting efficiency was increased to 70% when a monomer mixture containing about 10% methyl methacrylate was used. Grafting efficiency could be increased to over 90% if the graft polymerization of vinyl acetate‐methyl methacrylate was carried out near 0°C, although conversion of monomers to polymer was low and grafted polymer contained 40‐50% poly(methyl methacrylate). Selected graft copolymers were treated with methanolic sodium hydroxide to convert starch–g–poly(vinyl acetate) to starch–g–poly(vinyl alcohol). The molecular weight of the poly(vinyl alcohol) moiety was about 30,000. The solubility of starch–g–poly(vinyl alcohol) in hot water was less than 50%; however, solubility could be increased by substituting either acid‐modified or hypochlorite‐oxidized starch for unmodified starch in the graft polymerization reaction. Vinyl acetate was also graft polymerized onto acid‐modified starch which had been dispersed and partially solubilized by heating in water. A total irradiation dose of either 1.0 or 0.5 Mrad gave starch–g–poly(vinyl acetate) with about 35% add‐on, and a grafting efficiency of about 40% was obtained. A film cast from a starch–g–poly(vinyl alcohol) copolymer in which homopolymer was not removed exhibited a higher ultimate tensile strength than a comparable physical mixture of starch and poly(vinyl alcohol).

GRAFT POLYMERIZATION OF STYRENE AND VINYL ACETATE ONTO POLYESTER FIBERS IMBIBING CATALYSTS

Polyethylene terephthalate fibers (Tetoron) imbibing solutions of various catalysts (K2S2O8, (NH4)2S2O8, H2O2, BPO and AIBN) were heated with styrene in the air in sealed tubes. When the solvent of K2S2O8 and (NH4)2S2O8 was water the grafting proceeded only slightly, but when solvent was a water-methanol mixture the grafting proceeded to a considerable extent. In the cases of H2O2 the grafting proceeded smoothly even when the imbibing solvent was water. The fibers imbibing methanol solutions of AIBN could also be grafted with relatively high efficiencies.Dried fibers imbibing catalysts were heated with pure styrene or styrene-methanol mixtures, but the degree of grafting was low. Generally the graft efficiency of styrene onto the polyester fiber was lower than those onto cellulose, polyvinyl alcohol, nylon and polyvinyl chloride fibers. Behaviors of the grafting onto Vycron fiber were similar to those onto Tetoron fiber.The graft polymerization of vinyl acetate onto the polyester fibers was also investigated, but no desirable results were obtained. The difficulty of the grafting onto the polyester fibers may be mainly due to difficulty of penetration of the catalysts and/or the monomers into the fibers.

(229)ポリスチレンの臭素化,脱臭素化およびこれによる酢酸ビニルのグラフト重合

(229)ポリスチレンの臭素化,脱臭素化およびこれによる酢酸ビニルのグラフト重合