The kinetic behavior of the halato telechelic polymer (N,lV-dimethyl-.ÍV-[3-( l-pyrenyl)propyl]ammonio)trifluoromethanesnlfonate-end-capped poly(tetrahydrofuran) (POLYPROBE) in tetrahydrofuran is investigated by global compartmental analysis of the fluorescence decay surface. At low POLYPROBE concentrations the emission decays monoexponentially. When an analogous end-capped halato telechelic polymer without the pyrene chromophore ((Ñ,A,A-triethylammonio)trifluoromethanesulfonate-end-capped poly(tetrahydrofuran), POLYSALT) is added to solutions containing a low POLYPROBE concentration, the emission can be fitted by a biexponential decay function. From these observations it is concluded that the second excited-state species in the POLYPROBE-POLYSALT system is POLYPROBE involved in ion aggregation due to dipole-dipole or ion-dipole interaction. At higher POLYPROBE concentrations, without added POLYSALT, a triexponential decay function is needed to describe the emission. The third excited-state species is a POLYPROBE excimer, which can be formed via two pathways: either intermolecularly when a locally excited POLYPROBE encounters a ground-state POLYPROBE or intramolecularly when an aggregate of two POLYPROBE molecules rearranges. From the global compartmental analysis in which the value of one of the rate constants is scanned, it is found that the bimolecular processes are slowed down by the presence of the polymer chain, while intramolecular rearrangements are not affected.

: Telechelic polyacetals, obtained by cationic ring-opening polymerization of 1,3-dioxolane (DXL) and 1,3-dioxepane (DXP), have been used as building blocks for polymer materials. In the first part of this paper, the synthesis and the properties of networks based on polyDXL a,w-bis(methacry1ates)ai-e discussed. The second part deals with the synthesis and the properties of polyacetal polyurethanes. A thermoplastic polyurethane was prepared with poly(DXL-co-DXP) a,o-diol as soft segment and the combination butane-1,4-dioI and hexamethylene diisocyanate as hard segment. Polyurethane networks were obtained from polyacetal polyols and diphenylmethane diisocyanate (MDI). Some physical properties of these new materials are reported.

Two methods for the synthesis of branched (co)polymers by cationic ring‐opening polymerization are presented. The first method is based on the spontaneous intermolecular termination that is observed in the polymerization of the four‐membered cyclic sulfides (thietanes). The branching points in these polymers are sulfonium ions. This method has been extended to polyether ‐ polysulfide block copolymers obtained by sequential polymerization of THF and a thietane. In the thus obtained AB block polymers, the branching points are concentrated in the sulfide segments only. By similar techniques, ABA types of block copolymer networks have been obtained making use of bifunctional initiators. The second method consists of copolymerizing a cyclic acetal such as 1,3‐dioxolane (DXL), with a “monofer”, which is a monomer that contains also a chain‐transfer function. As monofers for the DXL polymerization glycidol and glycerol formal were used. The end products are polyacetal‐polyols which contain a hydroxyl group at each of the chain ends. Reaction of these polyols with di‐isocyanates leads to the corresponding polyacetal polyurethanes.

The excited-state processes of the halato-telechelic polymer bis [(N,N-dimethyl-N-[3-(1-pyrenyl)propyl]ammonio)trifluoromethanesulfonate]-end-capped poly(tetrahydrofuran) at low concentrations are investigated by time-resolved fluorescence. The photophysical processes can be described by an intramolecular three-state excited-state model. Such a system is not identifiable in the absence of a priori information. It is possible to perform a global compartmental analysis of the fluorescence decay surface using the scanning technique, based on model compound data previously obtained [Hermans et al., J. Phys. Chem. 1994, 98, 13583 and Hermans et al. Macromolecules 1995, 28, 3380]. The value boundaries on the rate constant for ring closure of the chain ends show that this process is close to diffusion-controlled.