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See detailControlled radical polymerization of methyl methacrylate initiated by an alkyl halide in the presence of the Wilkinson catalyst
Moineau, Georges; Granel, Claude; Dubois, Philippe ULg et al

in Macromolecules (1998), 31(2), 542-544

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See detailDual living free radical and ring opening polymerizations from a double-headed initiator
Hawker, Craig J; Hedrick, James L; Malmström, Eva E et al

in Macromolecules (1998), 31(2), 213-219

The concept of performing dual living polymerizations from a single initiating molecule with no intermediate activation, or transformation, steps is presented. The compatibility of “living”, or controlled ... [more ▼]

The concept of performing dual living polymerizations from a single initiating molecule with no intermediate activation, or transformation, steps is presented. The compatibility of “living”, or controlled free radical procedures, either nitroxide mediated or atom transfer radical polymerization (ATRP), with the living ring opening polymerization of ε-caprolactone, and vice versa, is demonstrated by the synthesis of a variety of well-defined block copolymers. For example, from a hydroxy-functionalized alkoxyamine, either the living ring opening polymerization of ε-caprolactone, or the “living” free radical polymerization of styrene can be performed leading to narrow polydispersity polymeric initiators. These polymeric initiators can then be used to initiate the living polymerization of the other monomer system without the need for intermediate steps. In a similar way, hydroxy-functionalized ATRP initiators can be used as bifunctional initiators for the polymerization of both ε-caprolactone and a variety of other vinyl monomers. The novel block copolymers that are obtained were shown to have low polydispersities and controllable molecular weights for both of the blocks. [less ▲]

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See detailShear-induced order in aqueous micellar solutions of amphiphilic poly(tert-butylstyrene)-b-poly(Na methacrylate) diblock
Leyh, Bernard ULg; Creutz, S.; Gaspard, J. P. et al

in Macromolecules (1998), 31(26), 9258-9264

Shear-induced order of aqueous micellar solutions of a poly(tert-butylstyrene)-b-poly(sodium methacrylate) diblock (c ) 2.5-15 w/v %) has been investigated by small-angle X-ray scattering. Data collected ... [more ▼]

Shear-induced order of aqueous micellar solutions of a poly(tert-butylstyrene)-b-poly(sodium methacrylate) diblock (c ) 2.5-15 w/v %) has been investigated by small-angle X-ray scattering. Data collected from a Couette cell in both radial and tangential geometries agree with a crystalline ordering of micelles in close packed hexagonal layers perpendicular to the velocity gradient, when c is in the 5-10 w/v % range. The measured interlayer distance is indeed very close to the value expected for a closepacked structure. The experimental data are consistent with a zigzag motion of adjacent planes upon shear. Shear-induced order is, however, restricted to a narrow concentration range just above the concentration for the sol-gel transition. This domain is thought to correspond to a regime where relative layer translation modes are allowed whereas mutual rotation is hindered. [less ▲]

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See detailVersatile and controlled synthesis of star and branched macromolecules by dentritic initiation
Trollsas, Michaël; Hedrick, James L.; Mecerreyes, David et al

in Macromolecules (1997), 30(26), 8508-8511

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See detailSynergism for the improvement of tensile strength in block copolymers of polystyrene and poly(n-butyl methacrylate)
Weidisch, R.; Michler, G. H.; Arnold, M. et al

in Macromolecules (1997), 30(25), 8078-8080

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See detailSmall-angle neutron scattering studies of low polarity telechelic ionomer solutions. 2. Single chain scattering
Karayianni, Eleni; Jérôme, Robert ULg; Cooper, Stuart L

in Macromolecules (1997), 30(24), 7444-7455

A direct probe of the single chain conformation in associating low polarity model telechelic ionomer solutions has been obtained using small-angle neutron scattering. A contrast matching technique was ... [more ▼]

A direct probe of the single chain conformation in associating low polarity model telechelic ionomer solutions has been obtained using small-angle neutron scattering. A contrast matching technique was employed utilizing a solution of hydrogenated and deuterated ionomer chains in a mixture of labeled and unlabeled solvent molecules. The scattering data at all concentrations and ionic levels examined show an excellent fit to the wormlike chain model. Single chain scattering patterns were obtained for two sodium-neutralized carboxy−telechelic polystyrene ionomers that differ by a factor of 2 in their molecular weight, in a concentration range from the dilute to the concentrated solution regime. The single chain dimensions were found to be influenced by both the ionic interactions and the extent of association. Both ionomer systems showed a contraction of the chain dimensions in the dilute solution regime which is more pronounced for the lower molecular weight telechelic ionomer. As concentration increases, the single chain dimensions increase until they reach a plateau value in the concentrated solution regime. This plateau value is very close to the chain dimensions of the ionomer in the bulk, as was found from a previous SANS study on similar ionomer systems. This plateau value chain dimension is also the same as the unperturbed dimension of the nonionic parent polymer in the bulk. The effect of concentration on the ionomer chain dimensions is attributed to the influence of ionic interactions as the nonionic form of the material shows larger chain dimensions in the concentration regime studied. These results indicate that intramolecular interactions with the formation of self loops prevail in the dilute solution regime. Intermolecular interactions with ionic groups connecting to different chains prevail in the concentrated solution regime, as evidenced by an extension of the chain dimensions. [less ▲]

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See detailDifunctional anionic initiator based on 1.3-diisopropenylbenzene. 5. Effect of polar additives and initiator seeding on the synthesis of poly(styrene-b-butadiene-b-styrene) copolymer
Yu, Y. S.; Dubois, Philippe ULg; Teyssié, Philippe et al

in Macromolecules (1997), 30(24), 7356-7362

The initiation of butadiene and styrene polymerization by a pure hydrocarbon soluble difunctional organolithium, 1,3-bis(1-lithio-1,3,3‘-trimethylbutyl)benzene, has been studied in a hydrocarbon solvent ... [more ▼]

The initiation of butadiene and styrene polymerization by a pure hydrocarbon soluble difunctional organolithium, 1,3-bis(1-lithio-1,3,3‘-trimethylbutyl)benzene, has been studied in a hydrocarbon solvent. The initiation occurs in such a way that part of the diadduct remains unreacted. When a second monomer feed along with tetrahydrofuran (THF) is added to the living chains, the residual diadduct is activated to the point where novel chains are formed. Weakly polar additives such as lithium alkoxides and aromatic ether can prevent part of the initiator from being inactive, although these additives are not effective enough to initiate the controlled synthesis of poly(styrene-b-butadiene-b-styrene) (SBS) triblock copolymers. The seeding of the initiator which consists of butadiene oligomerization in the presence of anisole and tBuOLi in cyclohexane, has proved to be very efficient in providing SBS containing 85% 1,4-microstructure polybutadiene (PBD) and with high mechanical properties, e.g., ultimate tensile strength higher than 30 MPa and elongation at a break of 1000%. [less ▲]

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See detailMolecular weight effects on polystyrene fingerprint time-of-flight secondary ion mass spectroscopy (ToF-SIMS) spectra
Vanden Eynde, X.; Bertrand, P.; Jérôme, Robert ULg

in Macromolecules (1997), 30(21), 6407-6416

Monodisperse polystyrenes (PS) of different molecular weights (Mn) synthesized by living anionic polymerization with three types of butyllithium initiator (linear, n; secondary, sec; and tertiary, tert ... [more ▼]

Monodisperse polystyrenes (PS) of different molecular weights (Mn) synthesized by living anionic polymerization with three types of butyllithium initiator (linear, n; secondary, sec; and tertiary, tert) were analyzed by ToF-SIMS (time-of-flight secondary ion mass spectrometry). The influence of the molecular weight on the secondary ion intensities was studied in detail for the fingerprint part of the mass spectra (with m/z < 200). A drastic effect was observed for Mn values below 104, related to the presence of the saturated butyl end group. An extra hydrogen transfer originating from this end group during the secondary ion formation must be invoked to explain the data. Only the first neighbor monomer repeat units seem to be affected. This H exchange increases the intensity of ions containing more hydrogen or needing H transfer for their formation as the tropylium ion (C7H7+ at m/z = 91). The molecular structure of the butyl end group is found to influence greatly not only the intensity of their parent ion but also the PS characteristic ion intensities. Indeed, the tert-butyl end group is seen unable to produce the H transfer observed for the n- and sec-butyl ones. A model is proposed to take the influence of the end group on the PS SIMS fragmentation pattern into account. The parameters of this model allow the quantification of the end group interaction. [less ▲]

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See detailPoly[poly(isobornyl methacrylate-co-methyl methacrylate) (poly(IBMA-co-MMA))-b-polybutadiene-b-poly(IBMA-co-MMA)] Copolymers: synthesis, morphology, and properties
Yu, J. M.; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (1997), 30(21), 6536-6543

Anionic random and block copolymerization of isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) has been studied in THF at −78 °C by using (1,1-diphenyl-3,3-dimethylbutyl)lithium (DDBLi) as ... [more ▼]

Anionic random and block copolymerization of isobornyl methacrylate (IBMA) and methyl methacrylate (MMA) has been studied in THF at −78 °C by using (1,1-diphenyl-3,3-dimethylbutyl)lithium (DDBLi) as initiator in the presence of LiCl. The random copolymerization of MMA and IBMA has also been carried out at 0 °C, all the other conditions being kept unchanged. Poly[poly(IBMA)-b-poly(BD)-b-poly(IBMA)] (IBI), poly[poly(IBMA-co-MMA)-b-poly(BD)-b-poly(MMA-co-IBMA)] (I/MBM/I), and poly[poly(IBMA)-b-poly(MMA)-b-poly(BD)-b-poly(MMA)-b-poly(IBMA)] (IMBMI) block copolymers have been synthesized by sequential anionic polymerization of butadiene, MMA, and IBMA initiated by the m-diisopropenylbenzene (m-DIB)/tert-butyllithium (t-BuLi) diadduct. These block copolymers of a monomodal and narrow molecular weight distribution (M̄w/M̄n = 1.1) have been analyzed by size exclusion chromatography (SEC), NMR, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). Stereocomplexation of IMBMA and I/MBM/I with iPMMA has also been studied by DSC. Although IBI triblock copolymers show a lamellar morphology even for relatively low hard block content (33 wt %), cylindrical and lamellar morphologies have been observed for the other block copolymers under consideration. These new block copolymers exhibit high ultimate tensile strength (30 MPa), elongation at break (1000%), and upper service temperature (140−200 °C). [less ▲]

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See detailAnionic block copolymerization of 4-vinylpyridine and tert-butyl methacrylate at "elevated" temperature : influence of various additives on the molecular parameters
Creutz, Serge; Teyssié, Philippe; Jérôme, Robert ULg

in Macromolecules (1997), 30(19), 5596-5601

The living anionic polymerization of 4-vinylpyridine (4VP) in 9/1 pyridine/THF at 0 °C has been reported lately (Creutz, S.; Teyssié, Ph.; Jérôme, R. Macromolecules 1997, 30, 1). The success of its block ... [more ▼]

The living anionic polymerization of 4-vinylpyridine (4VP) in 9/1 pyridine/THF at 0 °C has been reported lately (Creutz, S.; Teyssié, Ph.; Jérôme, R. Macromolecules 1997, 30, 1). The success of its block copolymerization with tert-butyl methacrylate (tBMA) has been shown to be dependent on the addition mode, highlighting the difference in reactivity between the two monomers. Moreover, the (co)solvent also strongly influences the fate of that copolymerization. Thus, the impact of various (co)solvents and additives has been investigated more thoroughly, revealing the interesting possibility of modifying the apparent relative reactivities of these two monomers. [less ▲]

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See detailIntramolecular excited-state processes of a halato-telechelic polymer, evaluated by global compartmental analysis of the fluorescence decay surface with the use of model coumpounds
van Stam, Jan; De Schryver, Frans C; Boens, Noël et al

in Macromolecules (1997), 30(19), 5582-5590

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 ... [more ▼]

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. [less ▲]

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See detailMacromolecular engineering of lactones and lactides. 24. Controlled synthesis of (R,S)-β-butyrolactone-b-ε-caprolactone block copolymers by anionic and coordination polymerization
Kurcok, Piotr; Dubois, Philippe ULg; Sikorska, Wanda et al

in Macromolecules (1997), 30(19), 5591-5595

Block copolymers of (R,S)-β-butyrolactone and ε-caprolactone have been synthesized by combining the anionic polymerization of the first monomer with the coordinative ring-opening polymerization of the ... [more ▼]

Block copolymers of (R,S)-β-butyrolactone and ε-caprolactone have been synthesized by combining the anionic polymerization of the first monomer with the coordinative ring-opening polymerization of the second one. The copolymerization yield is close to 100% and the final molecular weight of each sequence can be predicted from the initial monomer-to-initiator molar ratio. The molecular weight distribution of copolymers obtained is quite narrow (Mw/Mn ≤ 1.3). According to NMR and DSC analysis, the polybutyrolactone block is atactic and totally amorphous, in contrast to the polycaprolactone block which is semicrystalline. A partial miscibility of the two blocks in the amorphous phase has however been detected. Thermal and enzymatic degradations of the block copolymers have been investigated. The enzymatic degradation rate promoted by the lipase form Rhizopus arrhizus strongly depends on the copolyester composition and increases with the β-butyrolactone content. [less ▲]

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See detailPoly[methyl methacrylate (M)-b-styrene (S)-b-butadiene (B)-b-S-b-M] pentablock copolymers: synthesis, morphology, and properties.
Yu, Jian Ming; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (1997), 30(17), 4984-4994

A series of poly[methyl methacrylate (M)-b-styrene (S)-b-butadiene (B)-b-S-b-M], or MSBSM, pentablock copolymers have been successfully synthesized by sequential living anionic polymerization initiated ... [more ▼]

A series of poly[methyl methacrylate (M)-b-styrene (S)-b-butadiene (B)-b-S-b-M], or MSBSM, pentablock copolymers have been successfully synthesized by sequential living anionic polymerization initiated with the diadduct of tert-butyllithium (t-BuLi) onto m-diisopropenylbenzene (m-DIB) in a cyclohexane/diethyl ether mixture for the butadiene and styrene polymerization at room temperature and in a cyclohexane/THF mixture for the MMA polymerization at −78 °C. All the pentablock copolymers have a monomodal and narrow molecular weight distribution (Mw/Mn < 1.20), and their weight composition varies from 11 to 55% M, 18 to 55% S, and 15 to 64% B. Toluene-cast films of these copolymers have been analyzed by differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and transmission electron microscopy (TEM). All these materials show a phase separation of the soft B component from the hard S and M blocks, which cannot, however, be distinguished one from each other by DSC or DMA. Indeed, a single transition is observed for the binary hard phase at a temperature intermediate between the glass transition temperature of polystyrene (PS) and poly(methyl methacrylate) (PMMA). In addition to classical phase morphologies, such as cylindrical and lamellar phase organization, two nonclassical morphologies, i.e., catenoid−lamellar and strut phase structures have been observed by TEM. The phase morphology strongly depends on the pentablock composition and any chemical modification of blocks. For instance, the cylindrical morphology, characteristic of an MSBSM copolymer containing equal amounts of hard and soft phases, is changed into a lamellar morphology upon hydrogenation of the B midblock. Copolymers of a relatively low hard phase content typically behave as thermoplastic elastomers of high ultimate tensile strength (ca. 30 MPa) and elongation at break (ca. 900%). These mechanical properties, however, depend on the casting solvent. [less ▲]

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See detailTriblock copolymer based thermoreversible gels. 4. Effect of the midblock and characterization of the sol-gel transition
Yu, Jian Ming; Blacher, Silvia ULg; Brouers, F. et al

in Macromolecules (1997), 30(16), 4619-4625

Thermoreversible gelation has been studied in o-xylene for poly(methyl methacrylate) containing 80% syndiotactic triads (sPMMA) and block copolymers of the MXM type, where M is sPMMA and X is either ... [more ▼]

Thermoreversible gelation has been studied in o-xylene for poly(methyl methacrylate) containing 80% syndiotactic triads (sPMMA) and block copolymers of the MXM type, where M is sPMMA and X is either polybutadiene (PBD), hydrogenated PBD (PEB), poly(styrene-b-butadiene-b-styrene) (SBS) triblock, or the hydrogenated version of this triblock (SEBS). In o-xylene, which is a selective solvent for the central X block, sPMMA forms thermoreversible gels provided that the molecular weight is high enough. When sPMMA is the outer block of MXM triblock copolymers, the midblock X appears to favor the gelation and it considerably improves the thermal stability of the matured gels. This thermal stability is, however, largely independent of the actual nature of the midblock. The dynamic properties of solutions and gels have been analyzed and discussed on the basis of scaling assumptions. At the gel point, where the loss angle tan δc = G‘‘/G‘ is independent of the probing frequency, the sample obeys the typical power law G‘(ω) G‘‘(ω) ωΔ. The scaling exponent Δ is found in the 0.65−0.75 range for both sPMMA and MXM block copolymers, independent of the nature of the midblock. Modulus−frequency master curves have been built by using appropriate reaction time dependent renormalization factors for the individual frequency and modulus data. The scaling of these factors with reaction time has allowed us to calculate the static scaling exponents for the increase observed in both modulus and viscosity. The accordingly calculated values agree with the scalar elasticity percolation model. [less ▲]

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See detailDifunctional initiator based on 1,3-diisopropenylbenzene. 6. Synthesis of methyl methacrylate-butadiene-methyl methacrylate triblock copolymers
Yu, Y. S.; Dubois, Philippe ULg; Teyssié, Philippe et al

in Macromolecules (1997), 30(15), 4254-4261

Synthesis of PMMA−PBD−PMMA (MBM) triblock copolymers with a 1,3-diisopropenylbenzene- (DIB-) based initiator is studied. Diethyl ether, tert-butyl methyl ether, N,N,N‘,N‘-tetramethylethylenediamine (TMEDA ... [more ▼]

Synthesis of PMMA−PBD−PMMA (MBM) triblock copolymers with a 1,3-diisopropenylbenzene- (DIB-) based initiator is studied. Diethyl ether, tert-butyl methyl ether, N,N,N‘,N‘-tetramethylethylenediamine (TMEDA) and THF were found to be efficient polar additives for obtaining PMMA−PBD−PMMA triblock copolymers, but these triblock copolymers displayed a high 1,2-microstructure of the PBD block. A combination of the initiator seeding technique and weakly polar additives has allowed MBM triblock copolymers with high 1,4-microstructure of PBD to be obtained. These copolymers exhibited a definitely higher upper service temperature than conventional thermoplastic elastomers, i.e. SBS or SIS Kratons. The influence of chain microstructure, copolymer composition and block length on the mechanical properties has been studied. Short polystyrene blocks of ca. Mn 2000 have been incorporated in between the PBD central block and the PMMA outer sequences. A higher tensile strength was observed for these MBM-like triblock coplymers. Contamination by a diblock structure expectedly had a very depressive effect on the bulk properties, and the stress−strain behavior mainly depended on the PMMA content and secondarily on molecular weight. [less ▲]

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See detailExchange of polymer molecules between block copolymer micelles studied by emission spectroscopy. A method for the quantification of unimer exchange rates
Creutz, Serge; van Stam, Jan; Antoun, Sayed et al

in Macromolecules (1997), 30(14), 4078-4083

Amphiphilic block copolymers, composed of poly(sodium methacrylate) (PMANa) as the water soluble sequence and poly((dimethylamino)ethyl methacrylate) (PDMAEMA) as the hydrophobic sequence, were ... [more ▼]

Amphiphilic block copolymers, composed of poly(sodium methacrylate) (PMANa) as the water soluble sequence and poly((dimethylamino)ethyl methacrylate) (PDMAEMA) as the hydrophobic sequence, were anionically synthesized. Due to their amphiphilic character, these polymers aggregate into micelles in aqueous solutions. Of particular interest is the possibility of exchange of free chains, called unimers, between micelles and the bulk and the quantification of the exchange rate. The exchange of unimers between the micellar aggregates was determined spectroscopically. A donor molecule, naphthalene, was covalently bound to the hydrophobic blocks of the copolymers, while the acceptor, pyrene, was dissolved in aggregates built up from an identical, but unlabeled, copolymer. The energy transfer from an excited donor to a ground-state acceptor, with subsequent emission from the acceptor, was used to follow the migration of donor-labeled chains into micelles containing the dissolved acceptor. These data were analyzed according to a kinetic model, and the respective kinetic parameters could be determined. The influence of the relative composition of the block copolymer on the exchange rate was investigated to illustrate the usability of the kinetic model. While keeping the relative amount of comonomers as well as the molecular weights constant, the molecular architecture was also studied: hence the diblock (PDMAEMA-b-PMANa) and the corresponding triblocks (PDMAEMA-b-PMANa-b-PDMAEMA) and (PMANa-b-PDMAEMA-b-PMANa) were investigated. [less ▲]

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See detailMacromolecular engineering of polylactones and polylactides. 22. Copolymerization of ε-caprolactone and 1,4,8-trioxaspiro[4.6]-9-undecanone initiated by aluminum isopropoxide
Tian, Dong; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (1997), 30(9), 2575-2581

Novel biodegradable and biocompatible polyesters have been prepared by random copolymerization of ε-caprolactone (ε-CL) and 1,4,8-trioxaspiro[4.6]-9-undecanone (TOSUO) initiated by Al(OiPr)3. Copolyesters ... [more ▼]

Novel biodegradable and biocompatible polyesters have been prepared by random copolymerization of ε-caprolactone (ε-CL) and 1,4,8-trioxaspiro[4.6]-9-undecanone (TOSUO) initiated by Al(OiPr)3. Copolyesters of molecular weight (Mn) up to 104 and containing up to 90 mol % TOSUO repeating units have been prepared. The copolymer molecular weight is controlled by the molar ratio of the consumed comonomers and the initiator. The TOSUO constitutive units have been quantitatively deacetalized into ketones, which have also been efficiently reduced into hydroxyl groups without any apparent chain degradation. Therefore, poly(ε-caprolactone) (PCL) with well-defined content of ketone or hydroxyl pendent groups have been made available. The ε-CL and TOSUO comonomer units are randomly distributed within the copolymers, as assessed by the 13C-NMR sequence analysis. Indeed, the reactivity ratios (rC and rT) have been calculated from the average length of the ε-CL sequences (LC) and the TOSUO sequences (LT) and found to be 1.3 (rC) and 1.0 (rT), respectively. There is an interesting parallelism between the crystallinity and the average length of the ε-CL sequences. Copolyesters containing a molar fraction of TOSUO units smaller than 0.15 are semicrystalline, whereas the incorporation of larger amounts of TOSUO units results in amorphous copolyesters. Conversion of the ethylene acetal pendent groups into ketones and ultimately into hydroxyl pendent groups results in increasing glass transition temperature (Tg), melting temperature (Tm), and melting enthalpy (ΔHm). The thermal stability depends on the copolyester composition, since it decreases as the molar fraction of TOSUO units is increased. [less ▲]

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See detailMacromolecular engineering of polylactones and polylactides. 23. Synthesis and characterization of biodegradable and biocompatible homopolymers and block copolymers based on 1,4,8-trioxal [4.6] spiro-9-undecanone
Tian, Dong; Dubois, Philippe ULg; Jérôme, Robert ULg

in Macromolecules (1997), 30(7), 1947-1954

Homopolymers of 1,4,8-trioxa[4.6]spiro-9-undecanone (TOSUO) and block copolymers of TOSUO and ε-caprolactone (ε-CL) have been synthesized with aluminum isopropoxide as an initiator in toluene at 25 °C ... [more ▼]

Homopolymers of 1,4,8-trioxa[4.6]spiro-9-undecanone (TOSUO) and block copolymers of TOSUO and ε-caprolactone (ε-CL) have been synthesized with aluminum isopropoxide as an initiator in toluene at 25 °C. The homopolymerization is first order with respect to both monomer and initiator, and the end-group analysis agrees with a coordination−insertion mechanism based on the acyl-oxygen cleavage of the TOSUO ring. Living poly(ε-caprolactone) (PCL) and poly(1,4,8-trioxa[4.6]spiro-9-undecanone) (PTOSUO) chains are very efficient macroinitiators for the polymerization of TOSUO and ε-CL, respectively, with formation of block copolymers of a narrow molecular weight distribution. Size-exclusion chromatography (SEC) and 13C-NMR confirm the blocky structure of the copolymers, in agreement with DSC, which shows two glass transitions characteristic of the amorphous phase of PCL and PTOSUO, respectively. The ethylene ketal pendent groups of the PTOSUO block have been successfully converted to ketones and hydroxyl pendent groups without scission of the polyester backbone. These new materials have potential for applications in medicine, surgery, and tissue engineering. [less ▲]

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