Formation of crystalline inclusion compounds of poly (vinyl chloride) of different stereoregularity with γ‐cyclodextrin

Martínez, Gerardo; Gómez, M. A.; Villar–Rodil, S.; Garrido, Leoncio; Tonelli, Alan E.; Balik, C. M.

doi:10.1002/pola.22014

Cited by 13 publications

(5 citation statements)

References 45 publications

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“…It was hoped that, through the careful removal of the crystalline host CD lattice, the resulting coalesced polymer chains (c-polymers) would retain a significant degree of their included extended and un-entangled natures, so they would be organized in a manner quite different from samples processed from their solutions or melts, where they randomly coil and entangle. As we will now demonstrate, this has indeed been found to be the case [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,…”

Section: Introductionmentioning

confidence: 99%

Reorganizing Polymer Chains with Cyclodextrins

et al. 2017

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During the past several years, we have been utilizing cyclodextrins (CDs) to nanostructure polymers into bulk samples whose chain organizations, properties, and behaviors are quite distinct from neat bulk samples obtained from their solutions and melts. We first form non-covalently bonded inclusion complexes (ICs) between CD hosts and guest polymers, where the guest chains are highly extended and separately occupy the narrow channels (~0.5-1.0 nm in diameter) formed by the columnar arrangement of CDs in the IC crystals. Careful removal of the host crystalline CD lattice from the polymer-CD-IC crystals leads to coalescence of the guest polymer chains into bulk samples, which we have repeatedly observed to behave distinctly from those produced from their solutions or melts. While amorphous polymers coalesced from their CD-ICs evidence significantly higher glass-transition temperatures, T g s, polymers that crystallize generally show higher melting and crystallization temperatures (T m s, T c s), and some-times different crystalline polymorphs, when they are coalesced from their CD-ICs. Formation of CD-ICs containing two or more guest homopolymers or with block copolymers can result in coalesced samples which exhibit intimate mixing between their common homopolymer chains or between the blocks of the copolymer. On a more practically relevant level, the distinct organizations and behaviors observed for polymer samples coalesced from their CD-ICs are found to be stable to extended annealing at temperatures above their T g s and T m s. We believe this is a consequence of the structural organization of the crystalline polymer-CD-ICs, where the guest polymer chains included in host-IC crystals are separated and confined to occupy the narrow channels formed by the host CDs during IC crystallization. Substantial degrees of the extended and un-entangled natures of the IC-included chains are apparently retained upon coalescence, and are resistant to high temperature annealing. Following the careful removal of the host CD lattice from each randomly oriented IC crystal, the guest polymer chains now occupying a much-reduced volume may be somewhat "nematically" oriented, resulting in a collection of randomly oriented "nematic" regions of largely extended and un-entangled coalesced guest chains. The suggested randomly oriented nematic domain organization of guest polymers might explain why even at high temperatures their transformation to randomly-coiling, interpenetrated, and entangled melts might be difficult. In addition, the behaviors and uses of polymers coalesced from their CD-ICs are briefly described and summarized here, and we attempted to draw conclusions from and relationships between their behaviors and the unique chain organizations and conformations achieved upon coalescence.

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Section: Introductionmentioning

confidence: 99%

Reorganizing Polymer Chains with Cyclodextrins

et al. 2017

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“…Since the middle 1990s, our research group has formed a large number of crystalline CD‐ICs2–70 containing either high molecular weight guest polymers or small‐molecule guests that can serve as polymer additives [Fig. 1(b,c)].…”

Section: Introductionmentioning

confidence: 99%

Organizational stabilities of bulk neat and well‐mixed, blended polymer samples coalesced from their crystalline inclusion compounds formed with cyclodextrins

Tonelli

2009

J Polym Sci B Polym Phys

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Cyclodextrins (CDs) are cyclic starches containing a-1,4-linked glucose units. Commonly available a-, b-, and c-CDs have six, seven, and eight glucose units, respectively. They are well known for forming noncovalent inclusion complexes (ICs) with a variety of guest molecules, including many polymers, by threading and inclusion into their relatively hydrophobic interior cavities, which are roughly cylindrical, with diameters of $0.5-1.0 nm. Warm water washing of crystalline CD-ICs containing polymer guests insoluble in water or treatment with amylase enzymes serve to remove the host CDs and result in the coalescence of the guest polymers into solid bulk samples. When guest polymers are coalesced from their CD-ICs by carefully removing the host CD lattices, they are observed to solidify with structures, morphologies, and even conformations that are distinct from bulk samples made from their solutions and melts. In addition, molecularly mixed, intimate blends can be obtained upon coalescence of two or more normally immiscible polymer guests from their common CD-ICs. Not only are the organizations and behaviors of bulk polymer samples significantly modified on coalescence from their CD-ICs, but both are also maintained for significant periods of time even when heated above their T g s and T m s, where their chains are mobile. Here, we discuss the long-time, high temperature stabilities of the organizations and properties of bulk polymers coalesced from their crystalline CD-ICs. While random-coiling of their initially coalesced, largely extended, separated, and unentangled chains may be relatively rapid, we conclude that the subsequent slow establishment of homogeneous melts or phase-segregated blends results from the extremely sluggish center-of-mass diffusion that must accompany full entanglement of their chains. Apparently, the process of entangling the largely separated and not fully interpenetrating randomly coiled chains initially coalesced from their CD-ICs is particularly slow, much slower in fact than the center-of mass diffusion of polymer chains in their fully entangled melts. V V C 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys

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“…Plenty of other linear polymers, such as polyTHF, 43 polyesters, 44,45 aliphatic polyamides, 46 and even low molecular weight polyethylene, 47 form ICs with a-CD. Thicker polymers such as polypropylenoxide, 48 poly(tetrafluorethylenoxide-codifluormethylenoxide), 49 and polyaniline 50 are complexed by b-CD, whereas still thicker polymer chains such as polyisobutylene, 51 polymethylvinylether, 52 and polyvinyl chloride 53 form ICs with c-CD. All these examples are similar in that the polymer chains become nearly completely covered with CD rings, leading to crystalline channel structures that are insoluble in water.…”

Section: Threading Cds Onto Polymer Chainsmentioning

confidence: 99%

Cyclodextrin polyrotaxanes assembled from a molecular construction kit in aqueous solution

Wenz

2009

J. Polym. Sci. A Polym. Chem.

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ABSTRACT:We describe a molecular construction kit in which amphiphilic polymers and functionalized cyclodextrins are arranged into sophisticated molecular architectures in aqueous solution without the need to perform chemical reactions. Therefore, these systems are highly biocompatible and show programmable lifetimes. The kinetic stabilities of our polyrotaxane structures are tunable using sterically demanding groups that hinder dissociation. These cyclodextrinbased polymer systems are applicable in principle for the detection of analytes at the level of single molecules. These systems may also serve well in targeted drug delivery and gene transfection.

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Formation of crystalline inclusion compounds of poly (vinyl chloride) of different stereoregularity with γ‐cyclodextrin

Cited by 13 publications

References 45 publications

Reorganizing Polymer Chains with Cyclodextrins

Reorganizing Polymer Chains with Cyclodextrins

Organizational stabilities of bulk neat and well‐mixed, blended polymer samples coalesced from their crystalline inclusion compounds formed with cyclodextrins

Cyclodextrin polyrotaxanes assembled from a molecular construction kit in aqueous solution

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