The influence of the size and degree orderdering of macro-rings on the synthesis of polyrotaxanes

Lipatova, T.E.; Kosyanchuk, L. F.; Шилов, В. В.; Gomza, Yu. P.

doi:10.1016/0032-3950(85)90245-x

Cited by 15 publications

(8 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Because these fields have been recently reviewed extensively, 3,4 only brief mention of the various classes of polyrotaxanes will be noted here. These include the early work of Maciejewski et al with vinyl monomers and cyclodextrins, 5 Lipatova et al with polystyrene and cyclic urethanes, 6 Zilkha et al with poly(ethylene glycol)s and crown ethers, 7 the more recent efforts of the groups of Wenz, 8 Ritter, 9 Harada, 10 and Ooya 11 on other cyclodextrin-containing polyrotaxanes, and the work of Swager et al on crown etherbased polyrotaxanes. 12 In our laboratory we have reported a variety of polyrotaxanes based on crown ethers as the cyclic moieties; these have included polyesters, 13 polyamides, 14 polyurethanes, 15 and polystyrene, 16 among others.…”

Section: Introductionmentioning

confidence: 99%

Studies of the Formation of Poly(ester rotaxane)s from Diacid Chlorides, Diols, and Crown Ethers and Their Properties

et al. 1997

View full text Add to dashboard Cite

The formation of poly(alkylene sebacate-crown ether pseudorotaxane)s by condensation of linear alkylene diols and sebacoyl chloride in the presence of crown ethers in the neat state has been studied. It was found that the average number of crown ether molecules per repeat unit in the polypseudorotaxane was a function of (a) the ring size and (b) the stoichiometric ratio of macrocycle to diol but independent of (i) the equilibration time of the diol and crown ether prior to addition of the diacid chloride, (ii) the length of the diol, and (iii) the temperature of equilibration and polycondensation. All of these observations are consistent with the involvement of hydrogen bonding between the diol and the crown ether as a driving force for threading, except the lack of temperature dependence. Dethreading of the isolated polypseudorotaxanes was shown to be extremely slow. Therefore, it was reasoned that the lack of temperature dependence was due to dethreading during the polymerization, inasmuch as once the ester bond has formed there is no strongly attractive force between the linear and cyclic species and the low molecular weights of the growing oligomeric esters would permit relatively facile dethreading. Based on this idea, a bulky tetraphenylmethane-based bisphenol was employed to make a copolymer (1:4) with 1,10-decanediol; indeed, the purified polyrotaxane contained more than twice as much crown ether as the polypseudorotaxane from the linear diol, confirming that dethreading does occur during the polymerization process. The polyrotaxanes all were capable of extracting metal ions from aqueous solutions. In the cases with high loadings of crown ether two distinct crystalline phases were detected by DSC: one due to the polyester backbone and one due to the crown ether; glass transitions were also observed for the crown ether component of the polyrotaxanes. Polyrotaxanes possess higher intrinsic viscosities than the backbone polymers of the same molecular weight due to increased hydrodynamic volume brought about by the macrocyclic components. However, differential solvation of the backbone and cyclic components of the polyrotaxanes was demonstrated; the intrinsic viscosity of the polyrotaxane decreased in a good solvent for the crown ether. The temperature dependence of the melt viscosity of a polyrotaxane was essentially the same as that of the polyester model backbone, but the absolute melt viscosity was much lower due to reduced chain entanglement.

show abstract

Section: Introductionmentioning

confidence: 99%

Studies of the Formation of Poly(ester rotaxane)s from Diacid Chlorides, Diols, and Crown Ethers and Their Properties

et al. 1997

View full text Add to dashboard Cite

show abstract

“…Rotaxanes and polyrotaxanes are most successfully synthesized when the cycle and chain form specific interactions, which are exothermic, and therefore result in a high equilibrium constant for threading (Scheme ). In addition to direct complexation of the macrocycle and the linear components, threading may be directed by metal complexation with either the monomer/polymer, macrocycle, or both . Threading of cyclodextrins using hydrophobic interactions, which involve both an enthalpic and entropic component, is also high or even quantitative .…”

Section: Introductionmentioning

confidence: 99%

Amphiphilic Approach for Preparing Homopolyrotaxanes of Poly(ethylene oxide)

et al. 1997

View full text Add to dashboard Cite

A new concept was introduced for preparing homopolyrotaxanes that lack an enthalpic driving force for threading, and which are therefore truly a physical entrapment of non-interacting cyclic molecules and linear polymer chains. It is based on the ability of amphiphiles to form lamellae and columnar micelles in solvents that selectively solvate one of its components. An amphiphilic macrocrown ether (MC-12) with an average ring size of 42 atoms attached to a hydrophobic 12-carbon tail was prepared by formation of the macrocycle in the presence of multiple potassium template ions under pseudo-high dilution conditions. MC-12 is almost insoluble in aliphatic hydrocarbon solvents, but forms micelles in benzene and toluene in the presence of water. The micellar solutions of MC-12 macroscopically phase separate if water-soluble threads are added, but remain intact and solubilize less-water-soluble poly(ethylene glycol) (PEG) derivatives. PEG3350−bis(amine) threads do not react, or react incompletely, with tert-butyltrityl end-capping agents functionalized with benzaldehyde and acid chloride groups, respectively. The optimum end-capping reaction for PEG−bis(amine) threads in the water-induced micellar solutions of MC-12 is the addition reaction with 2-p-[tris(p-tert-butylphenyl)methyl]phenoxymethyl-4,4-dimethylazlactone.

show abstract

“…The resulting rotaxane networks may possess properties intermediate to semi-interpenetrating networks and networks plasticized with a low-molecular-weight additive. The analogy between polyrotaxanes/catenanes and interpenetrating network polymers has been made before 33) , but usually in the context of crosslinking preformed linear chains in the presence of large macrocycles 34) . The uncrosslinked polyurethanes and corresponding rotaxanes were soluble in HFIP and DMSO.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

Synthesis, dynamic mechanical, and solid-state NMR spectroscopy of crown-ether-based linear aliphatic polyurethane rotaxanes

Nagapudi¹,

Hunt²,

Shepherd³

et al. 1999

Macromol. Chem. Phys.

View full text Add to dashboard Cite

SUMMARY: Linear aliphatic polyurethanes were synthesized from hexamethylene diisocyanate (HDI) and either ethylene glycol (EG) or diethylene glycol (DEG). Polymerization of HDI and EG in a 30-crown-10 (30c10) solvent afforded poly[(ethylene hexamethylenediurethane) n -rotaxa-(30-crown-10) x ] with x/n = 0.02 (4% by mass). Polymerization of HDI and DEG in a 36-crown-12 (36c12) solvent provided poly[(oxydiethylene hexamethylenediurethane) n -rotaxa-(36-crown-12) x ] with x/n = 0.15 (23% by mass). For both polyurethane-rotaxanes, the melting temperatures are lower than those of the unthreaded backbones, and the glass temperature decreases when the threading efficiency is sufficiently high. The dynamic mechanical (DM) spectrum of the EG-30c10-containing polyrotaxane is identical to that of its unthreaded backbone. For both EG-based polymers, vacuum drying led to the disappearance of a sub-T g mechanical loss around -85 8C (1 Hz). The DM spectrum of the DEG-36c12-containing polyrotaxane contains additional loss peaks in its tan d versus temperature curves, as compared to its unthreaded backbone. Solid-state 2D WISE NMR revealed the new sub-T g loss process around -53 8C to be due to the onset of 36-crown-12 mobility in the polyrotaxane.

show abstract

The influence of the size and degree orderdering of macro-rings on the synthesis of polyrotaxanes

Cited by 15 publications

References 6 publications

Studies of the Formation of Poly(ester rotaxane)s from Diacid Chlorides, Diols, and Crown Ethers and Their Properties

Studies of the Formation of Poly(ester rotaxane)s from Diacid Chlorides, Diols, and Crown Ethers and Their Properties

Amphiphilic Approach for Preparing Homopolyrotaxanes of Poly(ethylene oxide)

Synthesis, dynamic mechanical, and solid-state NMR spectroscopy of crown-ether-based linear aliphatic polyurethane rotaxanes

Contact Info

Product

Resources

About