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Authors
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Perez, R. M. ; Sandler, J. ; Altstädt, V. ; Hoffmann, T. ; Pospiech, D. ; Ciesielski, M. ; Döring, M. ; Braun , U. ; Balabanovich, A. ; Schartel, B.
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Title
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Novel phosphorus-modified polysulfone as a combined flame retardant and toughness modifier for epoxy resins
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Date
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26.04.2007
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Number
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14204
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Abstract
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A novel phosphorus-modified polysulfone (P-PSu) was employed as a combined toughness modifier and a source of flame retardancy for a DGEBA/DDS thermosetting system. In comparison to the results of a commercially available polysulfone (PSu), commonly used as a toughness modifier, the chemorheological changes during curing measured by means of temperature-modulated DSC revealed an earlier occurrence of mobility restrictions in the P-PSu-modified epoxy. A higher viscosity and secondary epoxy-modifier reactions induced a sooner vitrification of the reacting mixture; effects that effectively prevented any phase separation and morphology development in the resulting material during cure. Thus, only about a 20% increase in fracture toughness was observed in the epoxy modified with 20 wt.% of P-PSu, cured under standard conditions at 180 °C for 2 h. Blends of the phosphorus-modified and the standard polysulfone (PSu) were also prepared in various mixing ratios and were used to modify the same thermosetting system. Again, no evidence for phase separation of the P-PSu was found in the epoxy modified with the P-PSu/PSu blends cured under the selected experimental conditions. The particular microstructures formed upon curing these novel materials are attributed to a separation of PSu from a miscible P-PSu–epoxy mixture. Nevertheless, the blends of P-PSu/PSu were found to be effective toughness/flame retardancy enhancers owing to the simultaneous microstructure development and polymer interpenetration.
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Publisher
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Polymer
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Wikidata
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25
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Citation
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Polymer 48 (2007) 778-790
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DOI
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https://doi.org/10.1016/j.polymer.2006.12.011
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Tags
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flame retardants phosphorus-modified polysulfone fracture toughness differential scanning calorimetry induced phase-separation diamine thermoset/thermoplastic blends structure-property relationships modified cure process mechanical-properties toughening m
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