@article{porbeni_shin_shuai_wang_white_jia_tonelli_2005, title={Morphology and dynamics of the poly(epsilon-caprolactone)-b-poly(L-lactide) diblock copolymer and its inclusion compound with alpha-cyclodextrin: A solid-state C-13 NMR study}, volume={43}, ISSN={["1099-0488"]}, DOI={10.1002/polb.20490}, abstractNote={A biodegradable diblock copolymer of poly(ϵ-caprolactone) (PCL) and poly(L-lactide) (PLLA) was synthesized and characterized. The inclusion compound (IC) of this copolymer with α-cyclodextrin (α-CD) was formed and characterized. Wide-angle X-ray diffraction showed that in the IC crystals α-CDs were packed in the channel mode, which isolated and restricted the individual guest copolymer chains to highly extended conformation. Solid-state 13C NMR techniques were used to investigate the morphology and dynamics of both the bulk and α-CD-IC isolated PCL-b-PLLA chains. The conformation of the PCL blocks isolated within the α-CD cavities was similar to the crystalline conformation of PCL blocks in the bulk copolymer. Spin–lattice relaxation time (T1C) measurements revealed a dramatic difference in the mobilities of the semicrystalline bulk copolymer chains and those isolated in the α-CD-IC channels. Carbon-observed proton spin–lattice relaxation in the rotating frame measurements (T1ρH) showed that the bulk copolymer was phase-separated, while, in the IC, exchange of proton magnetization through spin-diffusion between the isolated guest polymer chains and the host α-CD was not complete. The two-dimensional solid-state heteronuclear correlation (HetCor) method was also employed to monitor proton communication in these samples. Intrablock exchange of proton magnetization was observed in both the bulk semicrystalline and IC copolymer samples at short mixing times; however, even at the longest mixing time, interblock proton communication was not observed in either sample. In spite of the physical closeness between the isolated included guest chains and the host α-CD molecules, efficient proton spin diffusion was not observed between them in the IC. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2086–2096, 2005}, number={15}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Porbeni, FE and Shin, ID and Shuai, XT and Wang, XW and White, JL and Jia, X and Tonelli, AE}, year={2005}, month={Aug}, pages={2086–2096} }
 @article{rusa_wei_bullions_shuai_uyar_tonelli_2005, title={Nanostructuring polymers with cyclodextrins}, volume={16}, ISSN={["1099-1581"]}, DOI={10.1002/pat.566}, abstractNote={Abstract Bulk solid polymer samples formed by the coalescence of guest polymer chains from their inclusion compounds (ICs) formed with host cyclodextrins (CDs) can result in significant reorganization of their phase structures, morphologies, and even chain conformations from those more commonly produced from randomly‐coiled, entangled polymer solutions and melts. When the cyclic host CDs are threaded by polymer chains to form crystalline polymer‐CD‐ICs, the guest polymers become highly extended due to the narrow host CD diameters (∼5, 7, and 9 Å for α ‐, β ‐, and γ ‐CDs) and are segregated from neighboring guest polymer chains by the CD‐IC channel walls. As a consequence, when polymer‐CD‐IC crystals are treated with CD solvents that do not dissolve the guest polymers or are treated with amylase enzymes, the resulting coalesced bulk polymer samples often display properties distinct from those of normally produced bulk samples of the same polymers. In this article the CD‐IC processing of polymers to generate novel polymer microstructures and morphologies are described, to control the phase separation of immiscible blocks in block copolymers, and to form well‐mixed intimate blends of two or more polymers that are normally incompatible. The thermal and temporal stabilities of polymer samples coalesced from their ICs formed with CDs will also be mentioned, and it is suggested that the range of polymer properties can be greatly expanded by their CD‐IC processing. Copyright © 2005 John Wiley & Sons, Ltd.}, number={2-3}, journal={POLYMERS FOR ADVANCED TECHNOLOGIES}, author={Rusa, CC and Wei, M and Bullions, TA and Shuai, XT and Uyar, T and Tonelli, AE}, year={2005}, pages={269–275} }
 @article{rusa_shuai_shin_bullions_wei_porbeni_lu_huang_fox_tonelli_2004, title={Controlling the behaviors of biodegradable/bioabsorbable polymers with cyclodextrins}, volume={12}, ISSN={["1572-8919"]}, DOI={10.1023/B:JOOE.0000038547.36750.78}, number={3}, journal={JOURNAL OF POLYMERS AND THE ENVIRONMENT}, author={Rusa, CC and Shuai, X and Shin, ID and Bullions, TA and Wei, M and Porbeni, FE and Lu, J and Huang, L and Fox, J and Tonelli, AE}, year={2004}, month={Jul}, pages={157–163} }
 @article{rusa_wei_shuai_bullions_wang_rusa_uyar_tonelli_2004, title={Molecular mixing of incompatible polymers through formation of and coalescence from their common crystalline cyclodextrin inclusion compounds}, volume={42}, ISSN={["1099-0488"]}, DOI={10.1002/polb.20272}, abstractNote={We describe the successful mixing of polymer pairs and triplets that are normally incompatible to form blends that possess molecular-level homogeneity. This is achieved by the simultaneous formation of crystalline inclusion compounds (ICs) between host cyclodextrins (CDs) and two or more guest polymers, followed by coalescing the included guest polymers from their common CD–ICs to form blends. Several such CD–IC fabricated blends, including both polymer1/polymer2 binary and polymer1/ polymer2/polymer3 ternary blends, are described and examined by means of X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, and solid-state NMR to probe their levels of mixing. It is generally observed that homogeneous blends with a molecular-level mixing of blend components is achieved, even when the blend components are normally immiscible by the usual solution and melt blending techniques. In addition, when block copolymers composed of inherently immiscible blocks are coalesced from their CD–ICs, significant suppression of their normal phase-segregated morphologies generally occurs. Preliminary observations of the thermal and temporal stabilities of the CD–IC coalesced blends and block copolymers are reported, and CD–IC fabrication of polymer blends and reorganization of block copolymers are suggested as a potentially novel means to achieve a significant expansion of the range of useful polymer materials. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 4207–4224, 2004}, number={23}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Rusa, CC and Wei, M and Shuai, X and Bullions, TA and Wang, X and Rusa, M and Uyar, T and Tonelli, AE}, year={2004}, month={Dec}, pages={4207–4224} }
 @article{bullions_edeki_porbeni_wei_shuai_rusa_tonelli_2003, title={Intimate blend of poly(ethylene terephthalate) and poly(ethylene 2,6-naphthalate) via formation with and coalescence from their common inclusion compound with gamma-cyclodextrin}, volume={41}, ISSN={["1099-0488"]}, DOI={10.1002/polb.10366}, abstractNote={The experimental procedures to place poly(ethylene 2,6-naphthalate) (PEN) guest molecules within γ-cyclodextrin (γ-CD) host molecules are described along with the subsequent verification of inclusion-compound (IC) formation. In addition, the simultaneous complexing of PEN and poly(ethylene terephthalate) (PET) with γ-CD to form their common IC is documented. Coalescence from their common γ-CD IC generates an intimate blend of the PET and PEN polymers contained therein. Thermal analysis via differential scanning calorimetry reveals thermal behavior indicative of an intimate blend of PET and PEN. 1H NMR analysis confirms that the intimate blending of PET and PEN achieved by coalescence from their common γ-CD IC is not due to transesterification into a PET/PEN copolymer during thermal analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 139–148, 2003}, number={2}, journal={JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS}, author={Bullions, TA and Edeki, EM and Porbeni, FE and Wei, M and Shuai, X and Rusa, CC and Tonelli, AE}, year={2003}, month={Jan}, pages={139–148} }
 @article{wei_shuai_tonelli_2003, title={Melting and crystallization behaviors of biodegradable polymers enzymatically coalesced from their cyclodextrin inclusion complexes}, volume={4}, ISSN={["1526-4602"]}, DOI={10.1021/bm034078u}, abstractNote={Inclusion complexed (IC) and coalesced biodegradable poly(epsilon-caprolactone) (PCL), poly(L-lactic acid) (PLLA), and their diblock copolymer (PCL-b-PLLA) were achieved by forming ICs between host alpha-cyclodextrin(alpha-CD) and guest PCL, PLLA, and PCL-b-PLLA, followed by removing the alpha-CD host with an amylase enzyme. FTIR spectra of the coalesced polymers reveal that the host alpha-CD can be completely removed, without polymer degradation, by treatment with an amylase enzyme. The melting and crystallization behavior of these CD-IC treated polymers, which are crystallizable, biodegradable, and bioabsorbable, are investigated by differential scanning calorimetry (DSC) and polarized optical microscopy. Results show that coalescence increased the crystallinities of the homopolymers but decreased that of the diblock copolymer. The Avrami exponent (n), derived from both isothermal and nonisothermal crystallization models for homo-PCL and -PLLA and the PCL and PLLA blocks in the diblock copolymer samples coalesced from their ICs, is close to 4, indicating homogeneous crystallization, whereas crystallization of the blocks in the as-synthesized diblock copolymer yields an Avrami exponent around 3, indicating heterogeneous crystallization. All of these results demonstrate that the PCL and PLLA homopolymers and blocks in the IC-coalesced samples are more readily and homogeneously crystallized than those in the as-synthesized samples or their physical blend, even though the level of crystallinity in the IC-coalesced diblock copolymer is significantly lower. Moreover, unlike the as-synthesized diblock copolymer, the crystallization of PCL and PLLA blocks in the IC-coalesced diblock copolymer are not influenced by their covalent connection.}, number={3}, journal={BIOMACROMOLECULES}, author={Wei, M and Shuai, XT and Tonelli, AE}, year={2003}, pages={783–792} }
 @article{shuai_wei_porbeni_bullions_tonelli_2002, title={Formation of and coalescence from the inclusion complex of a biodegradable block copolymer and alpha-cyclodextrin. 2: A novel way to regulate the biodegradation behavior of biodegradable block copolymers}, volume={3}, ISSN={["1526-4602"]}, DOI={10.1021/bm015609m}, abstractNote={A biodegradable block copolymer (PCL-b-PLLA, M(n) = 1.72 x 10(4), M(w)/M(n) = 1.37) of poly(epsilon-caprolactone) (PCL) and poly(L-lactide) (PLLA) with very low crystallinity was obtained by forming the inclusion complex between alpha-cyclodextrin molecules and PCL-b-PLLA followed by coalescence of the guest polymer chains. Films of the as-synthesized and coalesced copolymer samples, PCL and PLLA homopolymers of approximately the same chain lengths as the corresponding blocks of PCL-b-PLLA, and a physical blend of PCL/PLLA homopolymers with the same molar composition as PCL-b-PLLA were prepared by melt-compression molding between Teflon plates. Subsequently, the in vitro biodegradation behavior of these films was studied in phosphate buffer solution containing lipase from Rhizopus arrhizus, by means of ultraviolet spectra, attenuated total reflectance FTIR spectra, differential scanning calorimetry, wide-angle X-ray diffraction measurements, and weight loss analysis. PCL segments were found to degrade much faster than PLLA segments, both in the pure state and in copolymer or blend samples. Consistent with our expectation, suppression of the phase separation, as well as a decrease of crystallinity, in the coalesced copolymer sample led to a much faster enzymatic degradation than that of either as-synthesized copolymer or the PCL/PLLA physical blend sample, especially during the early stages of biodegradation. Thus the biodegradation behavior of biodegradable block copolymers, which is of decisive importance in drug delivery and controlled release systems, may be regulated by the novel and convenient means recently reported by us.(1)}, number={1}, journal={BIOMACROMOLECULES}, author={Shuai, XT and Wei, M and Porbeni, FE and Bullions, TA and Tonelli, AE}, year={2002}, pages={201–207} }
 @article{shuai_porbeni_wei_bullions_tonelli_2002, title={Formation of inclusion complexes of poly(3-hydroxybutyrate)s with cyclodextrins. 1. Immobilization of atactic poly(R,S-3-hydroxybutyrate) and miscibility enhancement between poly(R,S-3-hydroxybutyrate) and poly(epsilon-caprolactone)}, volume={35}, ISSN={["0024-9297"]}, DOI={10.1021/ma011954s}, abstractNote={Atactic poly(R,S-3-hydroxybutyrate) (a-PHB) was synthesized by anionic polymerization of β-butyrolactone with potassium methoxide as an initiator. This completely amorphous polyester is capable of ...}, number={8}, journal={MACROMOLECULES}, author={Shuai, XT and Porbeni, FE and Wei, M and Bullions, T and Tonelli, AE}, year={2002}, month={Apr}, pages={3126–3132} }
 @article{shuai_porbeni_wei_bullions_tonelli_2002, title={Inclusion complex formation between alpha,gamma-cyclodextrins and a triblock copolymer and the cyclodextrin-type-dependent microphase structures of their coalesced samples}, volume={35}, ISSN={["0024-9297"]}, DOI={10.1021/ma012085+}, abstractNote={A triblock copolymer (PCL−PPG−PCL, Mn = 1.38 × 104) of poly(e-caprolactone) (PCL) and poly(propylene glycol) (PPG) was synthesized by ring-opening polymerization of e-caprolactone. Cyclodextrin (CD)-type-dependent formation of inclusion complexes (ICs) between cyclodextrins and this triblock copolymer was studied. Only PCL blocks were included as guests in the IC formed with α-cyclodextrin (α-CD), while both PCL and PPG blocks were included in the IC formed with γ-cyclodextrin (γ-CD). As a result, the copolymer coalesced from its IC crystals with α-CD showed an increased crystallinity, while to the contrary, the copolymer coalesced from its IC crystals with γ-CD exhibited a decreased crystallinity, when both were compared to the as-synthesized triblock copolymer. Fourier transform infrared (FTIR) spectra, 13C CP/MAS solid-state NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD) measurements were employed to study the formation of ICs as ...}, number={6}, journal={MACROMOLECULES}, author={Shuai, XT and Porbeni, FE and Wei, M and Bullions, T and Tonelli, AE}, year={2002}, month={Mar}, pages={2401–2405} }
 @article{shuai_probeni_wei_bullions_tonelli_2002, title={Stereoselectivity in the formation of crystalline inclusion complexes of poly(3-hydroxybutyrate)s with cyclodextrins}, volume={35}, ISSN={["0024-9297"]}, DOI={10.1021/ma012038h}, abstractNote={ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTStereoselectivity in the Formation of Crystalline Inclusion Complexes of Poly(3-hydroxybutyrate)s with CyclodextrinsXintao Shuai, Francis E. Porbeni, Min Wei, Todd Bullions, and Alan E. TonelliView Author Information Fiber and Polymer Science Program, College of Textiles, North Carolina State University, Raleigh, North Carolina 27695-8301 Cite this: Macromolecules 2002, 35, 9, 3778–3780Publication Date (Web):March 26, 2002Publication History Received21 November 2001Revised15 February 2002Published online26 March 2002Published inissue 1 April 2002https://doi.org/10.1021/ma012038hCopyright © 2002 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views395Altmetric-Citations60LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (42 KB) Get e-AlertsSUBJECTS:Cadmium sulfide,Cavities,Conformation,Physical and chemical processes,Polymers Get e-Alerts}, number={9}, journal={MACROMOLECULES}, author={Shuai, XT and Probeni, FE and Wei, M and Bullions, T and Tonelli, AE}, year={2002}, month={Apr}, pages={3778–3780} }
 @article{shuai_porbeni_wei_shin_tonelli_2001, title={Formation of and coalescence from the inclusion complex of a biodegradable block copolymer and alpha-cyclodextrin: A novel means to modify the phase structure of biodegradable block copolymers}, volume={34}, ISSN={["1520-5835"]}, DOI={10.1021/ma0109626}, abstractNote={A well-defined biodegradable block copolymer (PCL-b-PLLA, Mn = 1.72 × 104, Mw/Mn = 1.37) of poly(ε-caprolactone) (PCL) and poly(l-lactide) (PLLA) was synthesized by a two-step ring-opening polymerization of ε-caprolactone and l-lactide. Furthermore, we found that α-cyclodextrin (α-CD) molecules may simultaneously thread onto both PLLA and PCL blocks of PCL-b-PLLA to form an inclusion complex (IC). Washing the copolymer−α-CD IC with hot water removed the α-CD, and the copolymer chains were coalesced. Very interestingly, the coalesced copolymer sample shows a great suppression in microphase separation, compared with the as-synthesized copolymer. In contrast to the significant decrease in crystallinity of ca. 50% and up to 79% for PCL and PLLA blocks, respectively, the melting points (Tm's) and the cold crystallization temperatures (Tcc's) of both PCL and PLLA blocks of the coalesced sample increased in DSC measurements. These results may imply that only small amounts of more extended crystals, with less chain folding, were produced during the process of copolymer coalescence. Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and wide-angle X-ray diffraction (WAXD) measurements were employed to demonstrate formation of the block copolymer−α-CD IC as well as to gauge the suppression of the microphase separation in the coalesced sample.}, number={21}, journal={MACROMOLECULES}, author={Shuai, XT and Porbeni, FE and Wei, M and Shin, ID and Tonelli, AE}, year={2001}, month={Oct}, pages={7355–7361} }