Über hochpolymere Verbindungen, 94. Mitteil.: Über ein unlösliches Poly‐styrol

Staudinger, H.; Heuer, W.

doi:10.1002/cber.19340670709

Cited by 107 publications

(44 citation statements)

References 16 publications

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“…Staudinger and Heuer [2] could show that this insolubility was due to small amounts of tetrafunctional divinylbenzene present in styrene as an impurity from its synthesis. As little as 0.02 mass % is sufficient to make polystyrene of a molecular mass of 2001000 insoluble [3].…”

Section: Historymentioning

confidence: 98%

Microgels-Intramolecularly Crossünked Macromolecules with a Globular Structure

Funke

Okay

Joos-Müller³

Advances in Polymer Science

252

223

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Section: Historymentioning

confidence: 98%

Microgels-Intramolecularly Crossünked Macromolecules with a Globular Structure

Funke

Okay

Joos-Müller³

Advances in Polymer Science

252

223

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“…The first reports of mechanochemistry date back to Staudinger and the observation that high shear forces can induce a decrease of the molecular weight of poly(styrene) on account of the mechanically induced scission of covalent bonds . The deliberate force‐induced cleavage of polymers at specific active sites is a much more recent development .…”

Section: Mechanically Induced Cleavage Of Covalent and Noncovalent Bondsmentioning

confidence: 99%

Approaches to polymeric mechanochromic materials

Calvino

Neumann

Weder

et al. 2016

J. Polym. Sci. Part A: Polym. Chem.

133

129

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Mechanochromic materials respond to mechanical stimuli with a change of their optical properties. Such materials are of interest for many technological applications and support fundamental research as they help improving the understanding of stress transfer in polymeric objects and aid in the identification of the processes that lead to mechanical failure. In this highlight, different approaches are discussed that permit the design of polymeric materials, which signal mechanical stresses through a chromic response. This highlight emphasizes materials that exhibit mechanically induced changes of their intrinsic absorption or emission properties. These responses almost exclusively originate from changes of molecular structure, conformational rearrangements, or disruption of intermolecular interactions. V C 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 640-652

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“…In practice, yw is taken to be the weight-average degree of polymerization of the homopolymer from the monovinyl monomer polymerized under the same conditions. Equation (1) presupposes that the following conditions are met: first, the vinyl groups in the system are of equal reactivity; second, the pendent vinyl group of a singly reacted divinyl monomer is consumed only in interchain polymerization. Walling showed that eq.…”

Section: The Problem Of Gelationmentioning

confidence: 99%

“…&'lory's equation' relating the gel point to the amount of crosslinker and chain length of the uncrosslinked polymer states that: au = (TWX&l (1) where au is fractional conversion at the gel point, X D is the fraction of double bonds belonging to the divinyl monomerh the mixture, and TW is the weight-average degree of polymerizatioh of the "backbone chain." In practice, yw is taken to be the weight-average degree of polymerization of the homopolymer from the monovinyl monomer polymerized under the same conditions.…”

Section: The Problem Of Gelationmentioning

confidence: 99%

Copolymerization of styrene and p‐divinylbenzene. Initial rates and gel points

Storey¹

1965

J. Polym. Sci. A Gen. Pap.

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SynopsisInitial rates of polymerization were meaaured a t 70.0 and 89.7"C. for styrene, p divinylbenzene, and mixtures of the two monomers initiated with 1% benzoyl peroxide. The r a h relative to styrene increased linearly with mole fraction of pdivinylbenzene; the latter monomer polymerized faster than styrene by rr factor of 2.50 at 70.0"C. and 3.54 a t 89.7"C. Times to gelation were also measured for those aamplea containing p divinylbenzene, and from thew times the correeponding fractional converaion at the gel point waa calculated. The conversion a t the gel point passed through a minimum with increasing content of pdivinylbenzene. The gelation behavior is explained by concurrent interchain croaalinking to give a network and intrachaii crosslinking to give microgels which accumulate to give macrogel, the latter process being dominant at all but low concentrations of p-divinylbenzene. The higher the content of crosslinker, the leaa swollen the microgels, and the greater the conversion required to give gelation by this process. The linear increase in rate with increasing pdivinylbenzene rontent was aho explained by intrachin crosslinking: growing polymer radicals which undergo this procem have a reduced rate of termination. The factor by which the termination rate constant is reduced with increasing divinylbenzene content ia the same factor aa that by which the conversion required to give gelation by accumula.tion of microgels is increased. INTRODUCTIONThe copolymerization of divinylbenzene with styrene was first carried out by Staudinger' in order to demonstrate that crosslinking caused by the divinyl monomer would make the polystyrene insoluble in all solvents. In recent years, the insoluble gels obtained from copolymerization of these two monomers have become important as backbones for synthetic ion exchange resins. The properties of the finished copolymers have been studbut the copolymerization process itself has been virtually ignored. There is a practical reason for this: commercial divinylbenzene is a complex mixture containing both meta and para isoniers of divinylbenzcrie as well as other related hydrocarbons, and its composition is not a variable easily controlled in polymerization studies. This work was undertaken to remedy the lack of information on the rates and gel points of polymerizing styrenedivinylbenzene mixtures. The problems associated with commercial divinylbenzerie were avoided by using pure pdivinylbenzene, which can be separated from the commercial mixture by a brornination-debromination sequence. The Problem of GelationWhc.11 a iiionoviiiyl iii~iioiiier is copolytiierized.with a diviiiyl tnotioiiicr, the rcactioii niass will usually gcl at a coiivorsion characteristic of thc: monom m and the reaction conditions. The transition from fluid to gel is that point a t which a gas bubble or glass ball moving gently through the polymerizing mixture suddenly becomes immobilized. 111 other words, it is that point at which the mixture appears to develop a very small but finite yield stress. Th...

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Über hochpolymere Verbindungen, 94. Mitteil.: Über ein unlösliches Poly‐styrol

Cited by 107 publications

References 16 publications

Microgels-Intramolecularly Crossünked Macromolecules with a Globular Structure

Microgels-Intramolecularly Crossünked Macromolecules with a Globular Structure

Approaches to polymeric mechanochromic materials

Copolymerization of styrene and p‐divinylbenzene. Initial rates and gel points

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