Studies of dimethylacrylates as crosslinkers for styrene
| Autor: | Ian Holdaway, Ian W. Parsons, R.N. Haward, Ashok C. Shah |
|---|---|
| Rok vydání: | 1978 |
| Předmět: |
chemistry.chemical_classification
Materials science Polymers and Plastics Double bond Intrinsic viscosity Ethylene glycol dimethacrylate Organic Chemistry technology industry and agriculture macromolecular substances Polymer Styrene chemistry.chemical_compound chemistry PEG ratio Polymer chemistry Materials Chemistry Copolymer Ethylene glycol |
| Zdroj: | Polymer. 19:1067-1073 |
| ISSN: | 0032-3861 |
| DOI: | 10.1016/0032-3861(78)90149-0 |
| Popis: | Styrene has been thermally copolymerized to low conversions with small quantities of 14C labelled ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate and poly(ethylene glycol) (mol. wt ≈ 400) dimethacrylate. The competition between intramolecular cyclization and intermolecular crosslinking has been examined via studies of intrinsic viscosity, variation of the proportion of the crosslinker reacted at both vinyl groups with conversion, and changes in the polydispersity ratio. These studies indicate that in the early stages of reaction, reductions in intrinsic viscosity are found to be maximum in PEG(400)DM copolymers, followed by TEGDM—styrene copolymers and least in the EGDM—styrene system. Also, in zero conversion extrapolation analysis, the fraction of the crosslinker reacted at both the ends increases with the molecular weight of the ethylene glycol unit. These observations imply that intramolecular cyclization is favoured by increasing the distance of separation between the two vinyl end groups of the dimethacrylate crosslinker. The increase in the fraction of the crosslinker reacted at both ends with conversion is found to be most rapid in the PEG(400)DM—styrene copolymers and least in the EGDM—styrene copolymers. The increase in polydispersity ratio with conversion is also found to fall into the same sequence. These observations suggest that intermolecular crosslinking is also favoured by increasing separation between the two vinyl groups of the crosslinker, i.e. the reactivity of the double bond attached to the polymer chain is greater both for cyclization and intermolecular reaction when the length of the poly(ethylene glycol) unit is increased. |
| Databáze: | OpenAIRE |
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