Mechanical and thermal properties of poly(ethylene terephthalate) fibers crosslinked with disulfonyl azides

Thermally Induced Cross-Linking of Polymers via C,H Insertion Cross-Linking (CHic) under Mild Conditions

The focus of studies performed so far on the formation of surface-attached polymer networks by C,H insertion cross-linking (CHic) reaction has been largely on photochemical activation. This study describes the thermal activation of the formation of (surface-attached) polymer networks under comparably mild conditions. A novel cross-linker, based on a diazo phenyl ester group, is incorporated into various copolymers, which are subsequently deposited on solid substrates. Upon activation, the cross-linker moieties generate carbene intermediates, which lead to rapid, complete cross-linking of the whole film and simultaneous surface attachment to various organic materials via CHic. Although this system requires only comparably mild conditions (i.e., below 100 °C) to become activated, a long shelf life at room temperature is observed. The presented system might be useful in a wide range of applications, from coatings to rather complex geometries. We demonstrate the covalent binding of protein-repellent thin films to the inner surface of (rubber) tubes and the generation of patterned structures by a "branding iron" approach. For this a hot structure is pressed onto a diazo polymer coated surface, leading in the contact zone to fast cross-linking while in all other areas the polymer remains soluble and is washed off during subsequent extraction.

CROSSLINKING OF SATURATED ELASTOMERS WITH DIAZIDES. PART I: MECHANICAL PROPERTIES OF VULCANIZATES

For vulcanization of fully saturated elastomers peroxide/coagent systems are commonly applied. Problems encountered with peroxides however, are reduced efficiency, especially in the presence of plasticizing oils, and unwanted side reactions. In this paper diazides are presented as alternatives to peroxide vulcanization systems, particularly in combination with the use of plasticizing oils. The performance of three diazides; tri(ethylene glycol)-di(azidoformate) (GDAF), 4,4′-isopropylidenediphenyl azidoformate (4,4′DAF) and 1,3-benzenedisulfonyl azide (1,3BDSA) is investigated. For the evaluation of the practical product performance, carbon black filled and oil extended compounds of EPM and EPDM-rubbers are used. It is also investigated how the presence of carbon black and plasticizing oil influences the diazide reaction kinetics.