SynopsisA series of segmented ionene polymers based on the reaction of qw-bis(dimethy1 amino)polytetramethylene oxide with various dihalide compounds were investigated with respect to their structure-property behavior. The placement of quaternary ammonium ions and halide counterions along the polymer chains was varied by changing the molecular weight of the PTMO soft segment and the structure of the dihalide linking agent. The techniques of dynamic mechanical spectroscopy, thermal analysis, small angle X-ray scattering, and stress-strain behavior analysis were applied. For the case when the PTMO soft segment was amorphous, the ambient temperature properties of these materials displayed low modulus, high strength, and high elongation elastomeric behavior with tensile strength enhanced by the strain-induced crystallization of the PTMO. A high level of phase separation existed between the dihalide component relative to the PTMO soft segment. Due to the Coulombic association of the ionene species, these materials displayed many similarities to the segmented urethane ionomers. In particular, distinct domain structure was noted by SAXS, whose dimensional scale was similar to the segmented urethanes. It was also shown, however, that the driving forces for the microphase separation was caused by favorable electrostatic or Coulombic interactions in contrast to segment-segment incompatibility features as in the segmented urethanes.

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SynopsisThe reaction of a,w-bis(dimethy1amino) polytetramethylene oxide with various dihalides provided a series of elastomeric ionenes. The influence of dihalide structure on the reaction was studied and a number of substituents were found which dramatically increased the rate of polymerization and ultimate molecular weights achieved. These ionene elastomers were thermoplastic and it was shown that in some cases this result was due at least in part to a depolymerization reaction via a dequaternization of the ammonium links. Again, structural features in the dihalide were important not only for the reverse reaction, but for the repolymerization to high molecular weight elastomer as well. An uncharged "analogue" was also prepared to address the feature of microphase separation and compared with the above ionene materials.

Tetramethylammonium 3‐aminopropyl dimethylsilanolate, readily prepared from bis(3‐aminopropyl) tetramethyldisiloxane and tetramethyl‐ammonium hydroxide pentahydrate, has been found to serve as a highly effective catalyst for the ring opening polymerization of cyclic siloxanes with an end blocker such as bis(3‐aminopropyl) tetramethyldisiloxane to give aminopropyl terminated linear polydimethylsiloxanes. By following a novel two stage procedure, even high molecular weight (5,000–55,000 g/mol) silicone diamines were able to be prepared in a high state of purity; chain extension reactions of these diamines with diisocyanates gave a series of high molecular weight silicone polyureas with good elastomeric properties.

Hydrogen-bonding phenomena in amides and ureas are of great practical and theoretical importance. In this article, we report on infrared temperature studies aimed at the elucidation of the hydrogen-bonding phenomena of (meth)acrylamide groups directly linked to the alkyl groups of telechelic polydimethylsiloxane (PDMS) which serve as models of monoamides, or linked to the alkyl groups of telechelic PDMS through amide spacers-models of diamides (dipeptides). Similarly, we have examined the hydrogen-bonding phenomena in urea-terminated telechelic PDMSs to which free-radically polymerizable groups (methacrylate, amethylstyryl) are attached. Hydrogen bonding in the derivatives of these substituted silicone amides and ureas in the unreacted (liquid) state has been studied, as well as in films formed via ultraviolet-initiated free-radical polymerization of those reactive end-groups. The extreme flexibility of the silicones provides a medium in which polar, hydrogen-bonding end-groups (amides, diamides, and ureas) phase-separate to form their own domains wherein they can freely aggregate in an essentially unperturbed state, when in the liquid form. When the vinyl end-groups are polymerized, interactions between the hydrogen bonding groups attached to them can be studied in a spatially constrained environment. High thermal stability of the silicones allows the study of the hydrogen bonding (H-bonding) phenomena of these models within a broad temperature range. V C 2010Wiley Periodicals, Inc. J Appl Polym Sci 117: [982][983][984][985][986][987][988][989][990][991][992][993][994][995] 2010