Dilute gelling systems: copolymers of styrene and glycol dimethacrylates

Shah, Ashok C.; Parsons, Ian W.; Haward, R. N.

doi:10.1016/0032-3861(80)90303-1

Cited by 53 publications

(43 citation statements)

References 7 publications

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“…A similar trend has. been previously reported for vinyl-divinyl crosslinking copolym erization (19,(23)(24)(25)(26). The plateau is more clearly observed in Ref.…”

Section: Resultssupporting

confidence: 62%

Network defects in polyacrylamide gels

Baselga

Llorente

Hernández-Fuentes

et al. 1989

European Polymer Journal

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The weight conversion at the gel point (oc 0 ) was determined by the gas bubble method in two sets of polyacrylamide (PAA) gels crosslinked with' N,N'-methylene-bisacrylamide (BA). oc 0 remained practically constant when the crosslinker ratio was C = 10% (w/w) and the total concentration of comonomers in the feed ranged from C T = 5 to 10 g/100 mi. When C T was kept constant at 5 g/100 mi and C changed from O to 25% (w/w), oc 0 showed a minimum at C = 7%. By comparing the experimental values of oc 0 with those calculated for an ideal network, it was concluded that the crosslinking efficiency of BA is very low. The dependence on C of oc 0 and other properties like the elastic phantom modulus, 1/ ;h l, and the polymer volume fraction at swelling equilibrium, v 2 ,, was explained in terms of the formation of network defects: the formation of BA sequences longer than unity and that of intramolecular cycles both have an increasing contribution at C > 7% but can be neglected at lower values of C.

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“…A similar trend has. been previously reported for vinyl-divinyl crosslinking copolym erization (19,(23)(24)(25)(26). The plateau is more clearly observed in Ref.…”

Section: Resultssupporting

confidence: 62%

Network defects in polyacrylamide gels

Baselga

Llorente

Hernández-Fuentes

et al. 1989

European Polymer Journal

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“…In 1935, Staudinger et al 8) reported the formation of styrene-divinylbenzene microgel. Thereafter, numerous reports on microgel formation in the homopolymerizations of multivinyl compounds and their copolymerizations with monovinyl monomers were published 7,[9][10][11][12] . However, no microgelation was observed in the bulk polymerization of diallyl phthalate (DAP) 13) giving a quite low primary chain length as a characteristic feature of allyl polymerization 14) , although Erath et al 1) observed directly the DAP cured resin as the agglomerate of colloidal particles by electron microscopy.…”

Section: Introductionmentioning

confidence: 99%

ESR spectroscopic evaluation of void parts in microheterogeneously crosslinked monomethacrylate/dimethacrylate resins by using copper(II) tetraphenylporphyrin spin probe

Aota

Nishizawa

Matsumoto

2000

Macromol. Mater. Eng.

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confidence: 99%

“…It should be recalled that we have been concerned with crosslinking multiallyl polymerization 7,8 as compared with that of the opposite case of multivinyl systems, in which numerous reports about microgel formation were published on the homopolymerization of common multivinyl monomers and their copolymerization with common monovinyl monomers. [9][10][11][12][13] In our previous investigation, 14 we tried to clarify the inhomogeneous cross-link structure formation or the microgelation in the bulk polymerization of DAP because the cross-linked DAP resin consisted of colloidal particles when observed using electron microscopy. 15 However, our results clearly demonstrated that any microgelation leading to the formation of colloidal particles did not occur before the gel point.…”

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confidence: 99%

Microgel-like network polymer precursor formation in free-radical cross-linking multiallyl polymerization

Hamamoto

Himei

Inoue

et al. 2010

Polym J

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The present study is an extension of our preceding work on gelation behavior. We observed no substantial difference in the actual gel points among three isomeric diallyl phthalates: diallyl phthalate, diallyl isophthalate and diallyl terephthalate. The resulting network polymer precursors (NPPs) were characterized by size-exclusion chromatography with both multiangle laser light scattering and viscometry. It is of note that the structure of NPP, consisting of oligomeric primary polymer chains, becomes core-shell type dendritic or nanogel-like with the progress of polymerization. The nanogel-like NPPs can then collide with one another to form cross-links, eventually leading to gelation. Although the concentration of NPP should be high at the conversion close to the gel point, the dilution of NPP by adding monomer could prevent the cross-link formation among NPPs, and consequently lead to the successive growth of high-molecular-weight NPP from a nanogel to a microgel. The further growth of the microgel as an inhomogeneous NPP with high cross-link density could eventually reach an extremely inhomogeneous network polymer. These processes were pursued as typical examples using the bulk polymerization of DAT. Polymer Journal ( Keywords: cross-linking; gelation; microgel; multiallyl polymerization; nanogel; network polymer precursorIn our previous work, 1 the gel points in the free-radical polymerizations of diallyl aromatic dicarboxylates-including three isomeric diallyl phthalates: diallyl phthalate (DAP), diallyl isophthalate (DAI) and diallyl terephthalate (DAT)-were experimentally reexamined in detail and discussed according to Gordon's theory. 2 Although the discrepancy between actual and theoretical gel-point conversions was quite large and, moreover, it was enhanced in the order DAP o DAI o DAT, no substantial difference in the actual gel points was observed between the three isomeric DAPs. This interesting gelation behavior was discussed in detail 3 in terms of the correlation between gelation and the difference in cyclization modes, 4 as well as the difference in reactivity between the uncyclized and cyclized radicals for cross-linking. Conclusively, the nonconsecutive addition in DAT polymerization led to a delayed gelation, and the cyclized radical in DAP polymerization showed an enhanced reactivity for cross-linking.Then, we tried to extend our previous discussion 3 to the polymerization of triallyl trimellitate (TAT) because the chemical structure of TAT essentially exhibits the characteristics of three isomeric DAPs (Figure 1). Therefore, the enhanced gelation was expected in TAT polymerization, involving both abundant unreacted pendant double bonds and cyclized radicals as two significant factors responsible for an enhanced intermolecular cross-linking. However, no promoted gelation was observed in TAT polymerization when compared with DAP, DAI and DAT polymerizations.For a full understanding of the gelation behavior in cross-linking multiallyl polymerization, our preceding work 5 was focused on the cha...

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Dilute gelling systems: copolymers of styrene and glycol dimethacrylates

Cited by 53 publications

References 7 publications

Network defects in polyacrylamide gels

Network defects in polyacrylamide gels

ESR spectroscopic evaluation of void parts in microheterogeneously crosslinked monomethacrylate/dimethacrylate resins by using copper(II) tetraphenylporphyrin spin probe

Microgel-like network polymer precursor formation in free-radical cross-linking multiallyl polymerization

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