Approach to Ideal Network Formation Governed by Flory−Stockmayer Gelation Theory in Free-Radical Cross-Linking Copolymerization of Styrene with <i>m</i>-Divinylbenzene

Matsumoto, Akira; Kitaguchi, Yuji; Sonoda, Osamu

doi:10.1021/ma990368k

Cited by 39 publications

(49 citation statements)

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“…In the preceding article, 2 we have discussed the applicability of FS theory 3 for the crosslinking copolymerizations of St with m-DVB. The higher the theoretical gel point, the smaller the ratio of the actual gel point to the theoretical one.…”

Section: Resultsmentioning

confidence: 99%

“…2 Figure 1 shows the conversion dependence of weight-average molecular weight, M w (LS), of the prepolymer determined by LS; the prepolymer of a higher M w value was obtained for the copolymerization with a higher m-DVB mole percent log M w (LS) Conversion ( ) …”

Section: Resultsmentioning

confidence: 99%

Section: Mw (Sec Malls)/mw (Ls)mentioning

confidence: 98%

“…2 Conclusively, the degradation of resulting poly(St-co-m-DVB) prepolymers became marked with reduced occurrence of intramolecular crosslinking or the decrement of multiple crosslink or network structure, i.e., with approaching to ideal network formation governed by FS theory. 2 Next, we tried to examine the dependence of degradation on primary chain length of resulting prepolymers because the shorter primary chain inevitably leads to more highly branched structure in order to produce the prepolymer of ultrahigh molecular weight. Thus, three kinds of poly(St-co-m-DVB) prepolymers of different primary chain lengths were prepared as follows: St/m-DVB (molar ratio 99:1) copolymerizations were conducted in bulk in the absence and the presence of 2 × 10 −3 and 3.5 × 10 −3 mol L −1 of lauryl mercaptan as chain transfer agent using 0.04 mol L −1 of AIBN at 60 • C; the primary chain lengths, P w,0 , of resulting prepolymers were estimated to be 1190, 650, and 305, respectively.…”

Section: Mw (Sec Malls)/mw (Ls)mentioning

confidence: 98%

“…Polymerization was conducted as described previously. 2 SEC-MALLS measurements were carried out at 40 • C in tetrahydrofuran (THF) using a Shodex GPC KF-806L ×5 columns, at polymer concentrations 0.05-0.1% (w/v) and flow rate 1 mL min −1 . The MALLS device was a DAWN model F (Wyatt Technology Corp.) where the laser beam, of wavelength 632.8 nm, was focused on a 67 µL flow cell.…”

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Degradation of Ultrahigh Molecular Weight Poly(styrene-co-m-divinylbenzene)s as Network-Polymer Precursors in SEC Columns

Matsumoto

Aota

2002

Polym J

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KEY WORDSDegradation / SEC Column / Styrene / m-Divinylbenzene / Ultrahigh Molecular Weight / Network-Polymer Precursor / As an extension of our continuing studies concerned with the mechanistic discussion of the three-dimensional network formation in the freeradical polymerization and copolymerization of multivinyl compounds, 1 the preceding article 2 dealt with the crosslinking copolymerization of styrene (St) with m-divinylbenzene (m-DVB) as a most typical monovinyl/divinyl system. Thus, the reasons for the greatly delayed gelation from Flory-Stockmayer gelation theory (FS theory) 3 have been discussed extensively in order to clarify the crosslinking polymerization mechanism of multivinyl compounds. 1 The actual gel point should be close to the theoretical one if the experiment were done under the polymerization conditions in which the polymer concentration, at the theoretical gel point, would be high enough to reduce the significance of a thermodynamic excluded volume effect as a primary factor and, furthermore, the intramolecular crosslinking preceded by the intermolecular crosslinking could be suppressed. Our interpretations are verified for monomethacrylate/dimethacrylate, 4, 5 monoacrylate/diacrylate, 6 and St/m-DVB 2 copolymerizations, in which the results obtained are discussed in terms of ideal network formation according to FS theory.In a series of these investigations, the detailed pursuit of the variation of molecular-weight distribution (MWD) curves with conversion is inevitable for a full understanding of crosslinking polymerization because the MWD curves should rapidly broaden towards a higher molecular weight side with conversion as a result of exclusive occurrence of intermolecular crosslinking reaction leading to ideal network formation. 3,7,8 Here it is worthy to note that a size-exclusion chromatography (SEC) is commonly used to determine † To whom correspondence should be addressed. the molecular weight and the MWD of resulting prepolymers. However, as a technique it is not always applicable to our crosslinking polymerization systems because the structure of prepolymer changes from a linear to a branched form with progressing polymerization and, moreover, the content of ring or loop structure introduced into the linear portion or primary chain and the content of multiple crosslink or network structure in the branched form depend on the polymerization conditions. On the other hand, SEC equipped with a multiangle laser light scattering (MALLS) device (SEC-MALLS) is expected to be a very useful and efficient tool in characterizing our prepolymers because the use of MALLS, as an absolute detector, enables the molecular weight and MWD to be determined directly without any calibration. 5 During the progress of our investigation, we noticed that the degradation of poly(St-co-m-DVB) prepolymer of ultrahigh molecular weight obtained at the conversion close to the gel point occurred significantly in SEC columns. That is, the molecular weights determined by both SEC-MALLS and light scattering (LS) me...

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Mw (Sec Malls)/mw (Ls)mentioning

confidence: 98%

Section: Mw (Sec Malls)/mw (Ls)mentioning

confidence: 98%

mentioning

confidence: 99%

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Degradation of Ultrahigh Molecular Weight Poly(styrene-co-m-divinylbenzene)s as Network-Polymer Precursors in SEC Columns

Matsumoto

Aota

2002

Polym J

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Copolymerization

Barner‐Kowollik¹,

Coote²,

Davis³

et al. 2004

Encyclopedia of Polymer Science and Technology

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This article is primarily concerned with chain copolymerization. Chain copolymerization is important as it allows a wide array of functional molecules to be designed and incorporated into polymeric materials. The article starts with a general description of free‐radical copolymerization and the models that have been applied to facilitate mechanistic understanding. In recent years it has become evident that the reaction mechanism involved in free‐radical copolymerization propagation is appreciably more complicated than originally postulated in the terminal model developed back in the 1940s. For the simple prediction of composition the terminal model, although fairly crude, provides an adequate method in many instances. However, problems arise when it is used to study absolute rate coefficients (cross‐propagation rate coefficients) or when it is used to predict other quantities such as average propagation rates or sequence distribution. After consideration of copolymerization models, the article progresses to discuss the newly emerging field of controlled/living radical copolymerization, and the novel materials that can be made using these highly versatile synthetic methods. There is brief coverage of ionic chain copolymerization and cross‐linking copolymerization.

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Amphiphilic polymethacrylates as crosslinked polymer precursors obtained by free-radical monomethacrylate/dimethacrylate copolymerizations

Matsumoto

Ohashi

et al. 2000

J. Polym. Sci. A Polym. Chem.

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Approach to Ideal Network Formation Governed by Flory−Stockmayer Gelation Theory in Free-Radical Cross-Linking Copolymerization of Styrene with m-Divinylbenzene

Cited by 39 publications

References 19 publications

Degradation of Ultrahigh Molecular Weight Poly(styrene-co-m-divinylbenzene)s as Network-Polymer Precursors in SEC Columns

Degradation of Ultrahigh Molecular Weight Poly(styrene-co-m-divinylbenzene)s as Network-Polymer Precursors in SEC Columns

Copolymerization

Amphiphilic polymethacrylates as crosslinked polymer precursors obtained by free-radical monomethacrylate/dimethacrylate copolymerizations

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