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Chemistry

2001

Cross-linking

Articles 1 - 4 of 4

Full-Text Articles in Physical Sciences and Mathematics

Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Reaction Of P-Hydroxymethylbenzyl Chloride With Polystyrene, Hongyang Yao, Michael A. Mckinney, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie Jun 2001

Cross-Linking Of Polystyrene By Friedel-Crafts Chemistry: Reaction Of P-Hydroxymethylbenzyl Chloride With Polystyrene, Hongyang Yao, Michael A. Mckinney, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie

Chemistry Faculty Research and Publications

p-Hydroxymethylbenzyl chloride was found to be an effective cross-linking agent for polystyrene. The reaction was found to occur by Friedel–Crafts alkylation between the benzyl alcohol/chloride functional groups in the additive and phenyl ring in polystyrene. The reaction was studied by TGA–IR to monitor the evolution of hydrogen chloride and water, and the structure of the resultant gel was analyzed by solid state NMR and elemental analysis. The potential application in flame-retardancy was evaluated using Cone calorimetry.


Xps Characterization Of Friedel-Crafts Cross-Linked Polystyrene, Jiangqi Wang, Jianxin Du, Hongyang Yao, Charles A. Wilkie Jan 2001

Xps Characterization Of Friedel-Crafts Cross-Linked Polystyrene, Jiangqi Wang, Jianxin Du, Hongyang Yao, Charles A. Wilkie

Chemistry Faculty Research and Publications

The combination of a difunctional alkylating agent, either hydroxymethylbenzyl chloride or α,α′-dichloroxylene with polystyrene or high-impact polystyrene together with a Friedel-Crafts catalyst, 2-ethylhexyldiphenylphosphate, and an amine to react with hydrogen chloride has been studied by X-ray photoelectron spectroscopy. The results confirm what had been suggested from previous investigations using thermogravimetric analysis; cross-linking of the polymer occurs as the temperature is raised and the alcohol-containing alkylating agent gives a greater amount of cross-linking than does the dichloro compound.


An Xps Investigation Of Thermal Degradation And Charring Of Cross-Linked Polyisoprene And Polychloroprene, Jianwei Hao, Charles A. Wilkie, Jiangqi Wang Jan 2001

An Xps Investigation Of Thermal Degradation And Charring Of Cross-Linked Polyisoprene And Polychloroprene, Jianwei Hao, Charles A. Wilkie, Jiangqi Wang

Chemistry Faculty Research and Publications

Our interest in butadiene-containing polymers had led to an investigation of the thermal degradation of polyisoprene, PIP, and polychloroprene, PCP. The connection between cross-linking and thermal stability through an examination of PIP and PCP has been reported. Like the course of thermogravimetric analysis (TGA) the cross-linking and charring of polymers subjected to heat can also be experimentally observed as function of temperatures by the pseudo-in-situ XPS (X-ray Photoelectron Spectroscopy). Data acquisition of C1s spectra as function of temperature permits us to explore: (1) the extent of cross-linking and/or carbon accumulation of systems of PCP and PIP with/without initiators, BPO and …


The Thermal Stability Of Cross-Linked Polymers: Methyl Methacrylate With Divinylbenzene And Styrene With Dimethacrylates, Fawn Marie Uhl, Galina F. Levchik, Sergei V. Levchik, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie Jan 2001

The Thermal Stability Of Cross-Linked Polymers: Methyl Methacrylate With Divinylbenzene And Styrene With Dimethacrylates, Fawn Marie Uhl, Galina F. Levchik, Sergei V. Levchik, Caroline Dick, John J. Liggat, C.E. Snape, Charles A. Wilkie

Chemistry Faculty Research and Publications

Cross-linking of polymers is frequently presumed to enhance the thermal stability of polymer systems. Methyl methacrylate has been reacted with divinylbenzene and styrene with various dimethacrylates. These systems have been characterized by gel content, swelling ratio, infrared spectroscopy, thermal analysis, TGA/FT-IR, and solid state NMR. Both systems show enhanced thermal stability and char formation. This is most pronounced in the cases of methyl methacrylate with divinylbenzene and styrene with bisphenol A dimethacrylate.