Study on the initial stage of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) as a protective colloid

Suzuki, Atsushi; Yano, Makoto; Saiga, Tadanobu; Kikuchi, Kenji; Okaya, Takuji

doi:10.1007/s00396-002-0780-2

Cited by 15 publications

(13 citation statements)

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“…The PVA/VAc systems reached conversions of over 35% in the initial stage and increased relatively slow compared with the polymerization of MMA in the presence of PVA. This phenomenon could be understood easily by referring to the initiation reaction time of sulfate radical (τ 1 ) with different monomers [4,5]. As the initiation time of sulfate radical with VAc was 1.0×10 −7 s, which was approximately 100 times smaller than that of MMA (1.1× 10 −5 s), the VAc monomers conversed much rapidly than MMA in the beginning.…”

Section: Resultsmentioning

confidence: 97%

“…The reason of this phenomenon was attributed to the different kinetics of the grafting reaction between the monomers and PVA macromolecules, but the interpretation differed greatly among researchers. Some assumed this arose from the poor grafting ability of conjugated monomers such as acrylates and methacrylates [4][5][6], while excessive grafting of the soluble polymers was believed to be the influencing factor by others [7,8]. Relevant results have been reported that quite a large quantity of PVA was grafted in the polymerizations of n-butyl acrylate and methyl methacrylate monomers [9,10] and it was feasible to get stable emulsions by suppression of grafting [10][11][12][13][14], but the reason for the unstability of relevant colloids was not given and still indistinct.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of the different emulsion polymerization routes between acrylic and vinyl acetate monomers using poly(vinyl alcohol) as the sole stabilizer

Lin

Xia

2012

Colloid Polym Sci

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The emulsion polymerization of acrylic and vinyl acetate monomers using poly(vinyl alcohol) (PVA) as protective colloid has been studied for a long time, whereas rare reports ranged over the lateral comparison of the two systems and the reason for the unstability of the PVA/MMA polymerization system was still indistinct. Here in this paper, a collection of experiments of methyl methacrylate (MMA) and vinyl acetate (VAc) were performed respectively with varied amount of PVA as the sole stabilizer. The grafting extent of the polymerisate was characterized through the fraction and FTIR and it was found that the grafted amount of PVA was even larger in the PVA/MMA copolymers than PVA/VAc copolymers, so the grafted mode of PVA was considered. Based on the kinetics, the slower initiation rate of sulfate radical towards MMA was found to be responsible for the unstability of corresponding colloids accompanied with the relatively quicker hydrogen abstraction of radical to PVA, which resulted in "layer-by-layer" grafting structure inside and the particle surface-grafting density was lowered thereof. This was proved with TEM and static contact angle measurements and a pseudohomopolymer model was employed to describe the relationship of colloidal stability and the PVA density on surfaces.

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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Comparison of the different emulsion polymerization routes between acrylic and vinyl acetate monomers using poly(vinyl alcohol) as the sole stabilizer

Lin

Xia

2012

Colloid Polym Sci

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“…From the newly formed radical, a methoxyl radical may be formed as shown in Eq. (6). The methoxyl radical may react with the double bond in MMA forming a PMMA molecule with no sulfate end group.…”

Section: Resultsmentioning

confidence: 99%

“…In order to demonstrate the ability of grafting acrylics onto PVA, the authors employed a model experiment utilizing MMA as a representative of acrylics, and a very low monomer concentration (MMA/PVA/water = 1/1/100) that can be regarded as the initial stage of emulsion polymerization, since emulsion polymerization starts in the water phase. As the authors have reported in previous papers [3][4][5][6][7], grafting took place during the model polymerization: about 95% of polymerized MMA and approximately 65% of PVA were grafted. Surprisingly there was almost no difference between the results in MMA and VAc systems.…”

mentioning

confidence: 88%

Surface sulfate groups on poly(methyl methacrylate) and poly(vinyl acetate) particles from soap-free emulsion polymerization

et al. 2005

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Abstract:The amounts of sulfate groups on the particle surfaces of poly(methyl methacrylate) (PMMA) and poly(vinyl acetate) (PVAc) obtained in soap-free emulsion polymerization were determined. Polymerization was carried out at low monomer concentration using ammonium persulfate as an initiator. After the ionexchange procedure, conductometric titration was carried out. Amounts of surface sulfate groups were lower and particle diameter was larger in the PMMA system compared with PVAc. A large and remarkable difference appeared in the ratio of surface sulfate groups to decomposed sulfate radicals, viz. 90% for the PVAc system and 50% for PMMA. The ratios of sulfate groups per polymer molecule on PMMA and PVAc particles (functionality) were calculated. The functionality of the PMMA system was 70% of the theoretical value, while it was close to 100% in the PVAc system. This large difference might arise from the weak reactivity of the sulfate radical with MMA compared with that of VAc, due to the strong electrophilic nature of the radical. A side reaction of the sulfate radical with MMA is assumed. On the basis of these experimental results, the instability of the emulsion polymerization of acrylic monomers using poly(vinyl alcohol) (PVA) as a protective colloid is discussed in terms of the instability of the soap-free particles formed after the consumption of free PVA in water by the grafting reaction.

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“…The chain transfer of PVAc to polymer, monomer and solvent (methanol) during emulsion polymerization in the absence of the PVOH is also a very important subject. As a result of these significant branching reactions of PVAc, there are considerable research results in literature on this subject [27,30,[73][74][75][76][77][78].…”

Section: Emulsion Polymerization Of Vinyl Acetatementioning

confidence: 99%

Emulsion Polymerization: Effects of Polymerization Variables on the Properties of Vinyl Acetate Based Emulsion Polymers

Yamak¹

2013

Polymer Science

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Study on the initial stage of emulsion polymerization of vinyl acetate using poly(vinyl alcohol) as a protective colloid

Cited by 15 publications

References 0 publications

Comparison of the different emulsion polymerization routes between acrylic and vinyl acetate monomers using poly(vinyl alcohol) as the sole stabilizer

Comparison of the different emulsion polymerization routes between acrylic and vinyl acetate monomers using poly(vinyl alcohol) as the sole stabilizer

Surface sulfate groups on poly(methyl methacrylate) and poly(vinyl acetate) particles from soap-free emulsion polymerization

Emulsion Polymerization: Effects of Polymerization Variables on the Properties of Vinyl Acetate Based Emulsion Polymers

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