Endgroup studies in persulfate‐initiated vinyl polymer by dye techniques. Part I. Initiation by persulfate alone

Ghosh, Premamoy; Chadha, Subhash Chander; Mukherjee, A. R.; Palit, Santi R.

doi:10.1002/pol.1964.100021013

Cited by 36 publications

(14 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Again, the end group analysis 19 of the free homopolymer (PMMA) from the gross products gave a positive response for sulphate and hydroxyl end groups, which confirms the presence of sulphate ion radical (SO 4 Ϫ • ) and hydroxyl radicals ( • OH) as primary radicals in this system. Taking all of the above into consideration, the probable mechanism may be described as follows.…”

Section: Mechanismsupporting

confidence: 58%

Photograft copolymerization of methyl methacrylate on silk fiber using titanium(III) chloride-potassium persulphate redox initiator in a limited aqueous system. I

Maji

Banerjee

1999

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

Graft copolymerization of methyl methacrylate (MMA) onto mulberry silk fibers has been investigated in a limited aqueous system employing titanium(III) chloride-K 2 S 2 O 8 as the redox initiator under a photoactive condition with visible light. Polymerization in the presence of light at 32 Ϯ 1°C has been found to be more pronounced than in the dark under identical conditions. The percentage of grafting, the percentage of total conversion, and the percentage of grafting efficiency have been studied by varying the reaction time, concentration of monomer, initiator concentration, solvent composition, and pH of the medium. A high percentage of grafting (ϳ 93%), high grafting efficiency (ϳ 97%), and the percentage of total conversion (ϳ 25%) have been obtained with little homopolymer formation. Characterization of the grafted fibers has been investigated by Fourier transform infrared spectroscopy and scanning electron microscopy. Finally, the reaction mechanism has been discussed by considering hydrogen bonding.

show abstract

Section: Mechanismsupporting

confidence: 58%

Photograft copolymerization of methyl methacrylate on silk fiber using titanium(III) chloride-potassium persulphate redox initiator in a limited aqueous system. I

Maji

Banerjee

1999

J. Appl. Polym. Sci.

View full text Add to dashboard Cite

show abstract

“…This is because of the possibility that the initiator or end group may undergo a chemical reaction that will produce an end group that is a different chemical species entirely and may or may not be charged. For instance, one such reaction that is commonly known to occur with the sulfato radical produced from persulfate initiator is the hydrolysis reaction with water to produce a hydroxyl radical32 (the solid bullet • symbol denotes a radical species). This hydroxyl radical may then initiate polymerization in the water phase forming an hydroxyl end group on the polymer chain.…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium particle morphology development in seeded emulsion polymerization. III. Effect of initiator end groups

Stubbs

Sundberg

2003

J of Applied Polymer Sci

View full text Add to dashboard Cite

) we have explained the development of composite particle morphologies produced by seeded emulsion polymerization in terms of the ability of second stage polymer radicals to diffuse into, or "penetrate," the seed particles. This has been quantified (Stubbs et al., ibid) by calculating so-called "fractional penetration" values for the second-stage radicals. In this article the effect of the second-stage initiator type, specifically nonionic vs ionic initiators, on particle morphology is investigated. The question to be answered is whether charged (ionic) end groups (from the initiator) on second stage polymer chains "anchor" to the particle surface, making it more likely to form core-shell morphologies. This is investigated by using a poly(methyl acrylate-co-methyl methacrylate)[P(MA-co-MMA)] seed latex and polymerizing styrene in the second stage in a semibatch manner using various feed rates of styrene. At each feed rate one reaction was conducted using potassium persulfate as the initiator, which produces charged end groups, and another using VA-086 initiator, which produces uncharged end groups. The morphologies of the resulting particles were then observed by transmission electron microscopy. It is shown that under some conditions ionic initiators do make it more likely to obtain core-shell morphologies, but that this effect is not dominant under most conditions. The resulting morphologies agree quite well with the predictions of the fractional penetration calculations.

show abstract

“…Palit et al reported the presence of sulfate groups in polystyrene (PS) and PMMA prepared by persulfate initiator using the dye partition method [16][17][18][19][20]. The persulfate-initiated polymers contain very low amounts of sulfate end groups, about 0.05 -0.3 per polymer molecule for PS and 0.6 -0.7 for PMMA [18].…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2005

View full text Add to dashboard Cite

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.

show abstract

Endgroup studies in persulfate‐initiated vinyl polymer by dye techniques. Part I. Initiation by persulfate alone

Cited by 36 publications

References 14 publications

Photograft copolymerization of methyl methacrylate on silk fiber using titanium(III) chloride-potassium persulphate redox initiator in a limited aqueous system. I

Photograft copolymerization of methyl methacrylate on silk fiber using titanium(III) chloride-potassium persulphate redox initiator in a limited aqueous system. I

Nonequilibrium particle morphology development in seeded emulsion polymerization. III. Effect of initiator end groups

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

Contact Info

Product

Resources

About