Catalytic Ring-opening Polymerization Research Articles

Bio-based polyether from limonene oxide catalytic ROP as green polymeric plasticizer for PLA

In this work, the polymerization of Limonene Oxide (LO) has been achieved using an Earth abundant metal-based catalyst developed in our group, that is very active in ring opening polymerization (ROP) processes. The bio-based polylimonene ether (PLO) obtained had low molecular weight and good thermal properties, thus being a potential green polymeric additive for other bio-based polymers such as PLA. Hence, we have explored its ability to influence PLA properties. The addition of only 10 wt %, led to the modification and improvement of PLA properties in terms of flexibility, thermal stability, and hydrophobicity. The results obtained are promising and open up the potential industrial application of PLO for the melt-processing of blends based on PLA/PLO. These new materials are totally based on renewable sources and may be interesting for many applications where biodegradability and reduced water adsorption is required, such as food packaging or agricultural mulch films.

Neodymium monochloride and monoallyl complexes {2-[Ph2P(O)]C6H4NC(But)N(2,6-Me2C6H3)}2NdR (R = Cl, CH2CH=CH2) with the tridentate amidinate ligand in the catalysis of ring-opening polymerization of cyclic esters

The reaction of tridentate amidine 2-[Ph2P(O)]C6H4NHC(But)=N(2,6-Me2C6H3) (1) containing the side-chain donor group Ph2P=O with NdCl[N(SiMe3)2]2 (2) in a molar ratio of2:1 afforded the neodymium bis(amidinate) monochloride complex {2-[Ph2P(O)]-C6H4NC(But)N(2,6-Me2C6H3)}2NdCl (3). The neodymium bis(amidinate) monoallyl complex {2-[Ph2P(O)]C6H4NC(But)N(2,6-Me2C6H3)}2Nd(C3H5) (5) was synthesized by the elimination reaction between the tris-allyl derivative Nd(C3H5)3-(C4H8O2)2 (4) and amidine 1 in a molar ratio of 1:2 and by the exchange reaction between equimolar amounts of complex 3 and allylmagnesium bromide (C3H5MgBr). Complex 5 exhibits high activity as an initiator for the ring-opening polymerization of rac-lactide and e-caprolactone, providing the conversion of up to 500 equivalents of the rac-lactide and e-caprolactone within 5 and 2 min, respectively. The resulting polylactide samples have high number-average molecular weights ((47.38–93.02) · 103) and low polydispersity indices (Mw/Mn = 1.18–1.47). The polycaprolactone samples are characterized by high number-average molecular weights ((114.34–237.46) · 103) and a somewhat broadened molecular weight distribution (Mw/Mn = 1.87–2.40).

L2Zn and LZnX complexes bearing half-salphen ligands and their catalysis of ring-opening polymerization of ε -caprolactone

Zinc complexes L2Zn and LZnX were prepared by template synthesis from ZnX2, N1,N1-dimethylbenzene-1,2-diamine and substituted salicylaldehyde (SA). A systematic exploration of this synthetic route revealed the subtle role of choice of Zn source and SA substitution pattern on the reaction stoichiometry and enabled synthesis of pure Zn complexes. Use of poorly coordinating counterions (such as CF3SO3−) and apolar substituents on the SA component favours formation of pentacoordinate L2Zn, while more coordinating counterions tend to produce LZnX, (LZnX)2 or even binuclear LZn(O2CR)Zn(O2CR)2 not reported before. The complexes (LZnX)2 and LZn(O2CR)·Zn(O2CR)2 (L = L2 or L4) could be activated with BnOH/LiMe for ring-opening polymerization of ε-caprolactone; bis(ligand) complexes L2Zn show low or vanishing activity when activated either by BnOH or BnOH/LiMe.

Dual Catalytic Ring-Opening Polymerization of Ethylene Carbonate for the Preparation of Degradable PEG.

A dual catalytic setup, consisting of a range of different Lewis bases (including N-heterocyclic olefins, phosphazenes and nitrogen bases) and simple Lewis acids (such as LiCl, MgF2, BEt3), was employed to prepare poly(ether carbonate)s from five-membered, cyclic ethylene carbonate (EC). Polymerizations were conducted under microwave irradiation at T = 160-200 °C with low catalyst loading (0.4-0.005 mol % regarding organobases) in the bulk, enabling access to molar masses of up to 10 000 g/mol. A combination of kinetic investigation, GPC, MALDI-ToF MS, and NMR analysis underlines that the polymerization can be highly effective (TON up to >17 000) but side reactions still occur, resulting in a moderately controlled process. In contrast to traditional procedures, where increased ether contents can typically only be realized by higher temperatures and longer reaction times (at the cost of much reduced molar masses), the dual catalytic approach reveals the choice of the Lewis acid as a more effective tuning parameter for this property. Thus, while carbonate contents of up to 30% are possible, application of LiCl as cocatalyst provides a polymer with high ether content (90-99%, Mn = 800-10 000 g/mol), a finding that also seems to apply for other lithium salts. Thus, using this operationally simple setup and EC as a cheap feedstock, a copolymer which is essentially a degradable poly(ethylene glycol) can be prepared in a one-pot, one-step approach. Notably, the obtained low-carbonate content allows for the preparation of semicrystalline poly(ether carbonate), further underlining the "PEG-likeness" of the material.

Controlled and highly effective ring‐opening polymerization of α‐chloro‐ε‐caprolactone using Zn‐ and Al‐based catalysts

AbstractThe present study details the highly effective and controlled ring‐opening polymerization (ROP) of α‐chloro‐ε‐caprolactone (1, αClεCL), a cyclic ester that has been little explored thus far in ROP catalysis, using Zn‐ and Al‐based catalysts [Zn(C6F5)2(toluene)] (4), [N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)1,3‐diaminopropanato]aluminium(III)benzyloxide (5) and [N,N′‐bis(3,5‐di‐tert‐butylsalicylidene)1,3‐diamino‐2,2′‐dimethylpropanato]aluminium(III)benzyloxide] (6). Chain‐length‐controlled PαClεCL material is produced under solution ROP conditions, as deduced from GPC, NMR, MALDI‐TOF, and kinetic data. In contrast, the ROP of 1 is ill‐defined under bulk ROP conditions due to partial thermal degradation of the polymer chain (presumably through C–Cl cleavage), reflecting the limited stability of PαClεCL. The Al Catalysts 5 and 6 are highly active ROP catalysts of αClεCL at room temperature (TOF up to 2,400 hr−1) to afford well‐defined P(αClεCL). In the case of Catalyst 6, carrying out the ROP of αClεCL under immortal conditions (with BnOH as chain transfer agent) is clearly beneficial to ROP activity and control, with no apparent side‐reaction of chloro‐functionalized PCL chains as the ROP proceeds. The controlled character of these ROPs was further exploited for the production of chain‐length‐controlled PLLA‐b‐PαClεCL diblocks through sequential ROP of l‐lactide and αClεCL, affording copolymers with improved thermal and biodegradable properties.

Bis‐β‐(diketonates) Zn(II) complexes substituted with thiophene: Electropolymerization, homogeneous and heterogeneous catalysis for ring opening polymerization of lactide

ABSTRACTTwo Bis‐β‐diketonate zinc (II) complexes were synthesized using 1‐(thiophen‐2‐yl)butane‐1,3‐dione and 1‐(thiophen‐2‐yl)‐3‐(thiophen‐3‐yl)propane‐1,3‐dione as ligands. By electropolymerization of their thiophenyl groups, the metallopolymers deposited on FTO electrodes were obtained. The main objective was to study the reactivity of these compounds as ROP catalysts for PLA synthesis, using directly the zinc complexes (homogeneous catalysis) and also the modified electrodes with metallopolymers (heterogeneous catalysis). The homogeneous catalysis studies allowed the optimization of the polymerization conditions, such as reaction time, catalyst concentration, and the use of benzyl alcohol as cocatalyst, as well as their influence on the conversion rate, average molecular weight and polydispersity of PLA, using rac‐LA and L‐LA as monomers. Also, the effect on tacticity and thermal properties were discussed. Finally, the ROP studies using immersed modified electrodes in the polymerization medium were carried out under optimized experimental conditions. These tests were positive for one of the studied compounds, reaching conversions of up to 67%. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 557–567

Redox-switchable ring-opening polymerization by tridentate ONN-type titanium and zirconium catalysts

A study designed to ascertain the impact that ligand symmetry, number of redox-active moieties, and identity of the active metal center have on the catalytic ring-opening polymerization performance of redox-switchable catalysts.

The crucial roles of guest water in a biocompatible coordination network in the catalytic ring-opening polymerization of cyclic esters: a new mechanistic perspective.

The ring-opening polymerization (ROP) of cyclic esters/carbonates is a crucial approach for the synthesis of biocompatible and biodegradable polyesters. Even though numerous efficient ROP catalysts have been well established, their toxicity heavily limits the biomedical applications of polyester products. To solve the toxicity issues relating to ROP catalysts, we report herein a biocompatible coordination network, CZU-1, consisting of Zn4(μ4-O)(COO)6 secondary building units (SBUs), biomedicine-relevant organic linkers and guest water, which demonstrates high potential for use in the catalytic ROP synthesis of biomedicine-applicable polyesters. Both experimental and computational results reveal that the guest water in CZU-1 plays crucial roles in the activation of the Zn4(μ4-O)(COO)6 SBUs by generating μ4-OH Brønsted acid centers and Zn–OH Lewis acid centers, having a synergistic effect on the catalytic ROP of cyclic esters. Different to the mechanism reported in the literature, we propose a new reaction pathway for the catalytic ROP reaction, which has been confirmed using density functional theory (DFT) calculations, in situ diffuse reflectance IR Fourier transform spectroscopy (DRIFTS), and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS). Additionally, the hydroxyl end groups allow the polyester products to be easily post-modified with different functional moieties to tune their properties for practical applications. We particularly expect that the proposed catalytic ROP mechanism and the developed catalyst design principle will be generally applicable for the controlled synthesis of biomedicine-applicable polymeric materials.

Organocatalytic ring-opening polymerization of disulfide functional macrocyclic carbonates: An alternative strategy to enzymatic catalysis

Ring-opening polymerization (ROP) of macrocyclic carbonates (≥12 ring) is still challenging due to the associated low ring-strain. Although organometallic and enzyme based catalysts have been studied, disadvantages such as organometallic residue and enzymic nature limit their applications. After screening commercially available organocatalysts, we report the use of organocatalysts for ROP of disulfide-containing macrocyclic carbonates (MSS, 16 ring). It was found that organocatalysts (TBD) presented high active and living ROP of MSS, as evidenced by kinetic studies, yielding main chain disulfide-containing polycarbonates with tailor-made structures and predictable molecular weights with low molecular weight distribution. Copolymerizations with trimethylene carbonate (TMC) generated random copolymers with controlled components, regulating the density of disulfide functional groups. By comparing with the behaviors of enzyme catalysis in kinetic studies and (co-)polymerization, it is observed that organic catalyzed ROP showed more efficient (~ ten times faster), milder condition and more controlled behaviors than enzyme catalyzed ROP (N-435). Therefore, we believe this organic catalyzed strategy will provide an alternative to the current enzymatic and organometallic catalyst for ROP of macrocyclic carbonates.

Development of Inherently Flame—Retardant Phosphorylated PLA by Combination of Ring-Opening Polymerization and Reactive Extrusion

In this study, a highly efficient flame-retardant bioplastic poly(lactide) was developed by covalently incorporating flame-retardant DOPO, that is, 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide. To that end, a three-step strategy that combines the catalyzed ring-opening polymerization (ROP) of L,L-lactide (L,L-LA) in bulk from a pre-synthesized DOPO-diamine initiator, followed by bulk chain-coupling reaction by reactive extrusion of the so-obtained phosphorylated polylactide (PLA) oligomers (DOPO-PLA) with hexamethylene diisocyanate (HDI), is described. The flame retardancy of the phosphorylated PLA (DOPO-PLA-PU) was investigated by mass loss cone calorimetry and UL-94 tests. As compared with a commercially available PLA matrix, phosphorylated PLA shows superior flame-retardant properties, that is, (i) significant reduction of both the peak of heat release rate (pHRR) and total heat release (THR) by 35% and 36%, respectively, and (ii) V0 classification at UL-94 test. Comparisons between simple physical DOPO-diamine/PLA blends and a DOPO-PLA-PU material were also performed. The results evidenced the superior flame-retardant behavior of phosphorylated PLA obtained by a reactive pathway.

Kinetic and biocompatibility investigation on the catalytic ring opening polymerization of l-lactide in bulk using cyclic Bu2Sn initiators derived from ethylene glycol, pentaerythritol and cloisite 30B

In the present work, considering a green approach, PLLA was synthesized by the ring-opening polymerization of l-LA using various cyclic initiators (2,2-dibutyl-2-stanna-1,3-dioxacyclo ethane (1), spirocyclic tin (3) and cloisite modified tin (5)). PLLA was characterized by size exclusion chromatography, differential scanning calorimetry, 1H and 13C NMR, XRD and MALDI-TOF. The molecular weight distribution was narrow (<1.5) for both low and high molecular weights (>85,000 g/mol). An X-ray study showed the crystalline nature of PLLA, irrespective of the different types of initiators and polymerization conditions. A kinetic investigation showed that all polymerizations were first order with respect to the monomer and no termination reactions occurred during the polymerization. MALDI-TOF spectra of PLLA chains doped with Na+ and K+ cations show that the PLLA prepared using initiators 1 and 3 have hydroxyl and carboxyl end groups without incorporation of tin. The MALDI-TOF spectrum of PLLA prepared using initiator 5 also enabled the simultaneous detection of the linear and cyclic structure of PLLA without tin. Biocompatible and biodegradable PLLA was obtained, which could be used for biomedical applications.

DFT Visualization and Experimental Evidence of BHT-Mg-Catalyzed Copolymerization of Lactides, Lactones and Ethylene Phosphates.

Catalytic ring-opening polymerization (ROP) of cyclic esters (lactides, lactones) and cyclic ethylene phosphates is an effective way to process materials with regulated hydrophilicity and controlled biodegradability. Random copolymers of cyclic monomers of different chemical nature are highly attractive due to their high variability of characteristics. Aryloxy-alkoxy complexes of non-toxic metals such as derivatives of 2,6-di-tert-butyl-4-methylphenoxy magnesium (BHT-Mg) complexes are effective coordination catalysts for homopolymerization of all types of traditional ROP monomers. In the present paper, we report the results of density functional theory (DFT) modeling of BHT-Mg-catalyzed copolymerization for lactone/lactide, lactone/ethylene phosphate and lactide/ethylene phosphate mixtures. ε-Caprolactone (ε-CL), l-lactide (l-LA) and methyl ethylene phosphate (MeOEP) were used as examples of monomers in DFT simulations by the Gaussian-09 program package with the B3PW91/DGTZVP basis set. Both binuclear and mononuclear reaction mechanistic concepts have been applied for the calculations of the reaction profiles. The results of calculations predict the possibility of the formation of random copolymers based on l-LA/MeOEP, and substantial hindrance of copolymerization for ε-CL/l-LA and ε-CL/MeOEP pairs. From the mechanistic point of view, the formation of highly stable five-membered chelate by the products of l-LA ring-opening and high donor properties of phosphates are the key factors that rule the reactions. The results of DFT modeling have been confirmed by copolymerization experiments.

(Benz)Imidazolin-2-iminato Aluminum, Zinc, and Magnesium Complexes and Their Applications in Ring Opening Polymerization of ε-Caprolactone.

Synthesis and characterization of a new family of aluminum, magnesium, and zinc complexes supported by (benz)imidazolin-2-iminato ligands are reported herein. Under different reaction conditions, (benz)imidazolin-2-imine ligands reacted with metal alkyl precursors to afford the corresponding complexes, displaying mononuclear, binuclear, and trinuclear structures. Reaction in 1:1 stoichiometry at room temperature afforded the simple Lewis acid-base adducts, which exhibited distorted tetrahedral geometries around the metal centers, whereas high temperature reactions gave rise to dimeric complexes, with each metal bridging two (benz)imidazolin-2-imine ligands to form a four-membered metallacycle ring at the center of the complexes. The catalytic ring opening polymerization (ROP) of ε-caprolactone was studied using these complexes as precatalysts in the presence of isopropanol, and very high activities were observed, affording high/medium molecular weight poly(ε-caprolactone) products with low polydispersity indices. Detailed kinetic studies revealed that the polymerizations proceeded in a living manner and molecular weights of the polymers could be precisely controlled.

Fast and selective organocatalytic ring-opening polymerization by fluorinated alcohol without a cocatalyst

Organocatalysis is an important branch of catalysis for various organic transformations and materials preparation. Polymerizations promoted by organic catalysts can produce polymeric materials without any metallic residues, providing charming materials for high-value and sensitive domains such as biomedical applications, microelectronic devices and food packaging. Herein, we describe a fluorinated alcohol based catalytic system for polypeptide synthesis via catalytic ring-opening polymerization (ROP) of α-amino acid N-carboxyanhydride (NCA), fulfilling cocatalyst free, metal free, high rate and high selectivity. During polymerization, the fluorinated alcohol catalyst forms multiple dynamic hydrogen bonds with the initiator, monomer and propagating polymer chain. These cooperative hydrogen bonding interactions activate the NCA monomers and simultaneously protect the overactive initiator/propagating polymer chain-ends, which offers the whole polymerization with high activity and selectivity. Mechanistic studies indicate a monocomponent-multifunctional catalytic mode of fluorinated alcohol. This finding provides a metal free and fast approach to access well-defined polypeptides.

Alkali metal complex-mediated ring-opening polymerization of rac-LA, ε-caprolactone, and δ-valerolactone

Catalytic ring opening polymerization (ROP) of rac-lactide, ε-caprolactone, and δ-valerolactone using alkali metal (Li, Na, K) complexes as competent catalysts are reported.

Highly active tridentate amino-phenol zinc complexes for the catalytic ring-opening polymerization of ε-caprolactone

Tridentate 2,6-bis(imino)phenol (L1−L4) and 2,6-bis(amino)phenol (L5−L8) ligands and their corresponding zinc chloride complexes (1–8) have been synthesized and well characterized by FT-IR, 1H and 13C NMR, elemental analysis and single-crystal X-ray diffraction analysis. It was found that zinc complexes (1–4) with 2,6-bis(imino)phenol ligands were inactive for the ring-opening polymerization (ROP) of ε-caprolactone (ε-CL) even if they were activated by methyllithium. Zinc complexes (5–8) with 2,6-bis(amino)phenol ligands were proved to be highly efficient initiators for the ROP of ε-CL in combination with 4 equiv. of methyllithium. The ROP of ε-CL in the absence or presence of benzyl alcohol, including the influence of monomer ratio, reaction temperature and the substituents in the ligands, were investigated. The structure and thermal properties of obtained polymers were analyzed by NMR and MALDI-TOF mass spectra, DSC and TGA, respectively.

Enhanced Reactivity of Aluminum Complexes Containing P-Bridged Biphenolate Ligands in Ring-Opening Polymerization Catalysis.

Aluminum complexes containing [RP(O)(2-O-3,5-tBu2C6H2)2]2− [R = tBu (3a), Ph (3b)] have been synthesized, structurally characterized, and their reactivity studied in comparison with those of their [RP(2-O-3,5-tBu2C6H2)2]2− [R = tBu (2a), Ph (2b)] analogs. Treating AlMe3 with one equiv of H2[3a-b] in THF at 0°C affords quantitatively [3a-b]AlMe, subsequent reactions of which with benzyl alcohol in THF at 25°C generate {[3a-b]Al(μ2-OCH2Ph)}2. The methyl [3a-b]AlMe and the benzyloxide {[3a-b]Al(μ2-OCH2Ph)}2 are all active for catalytic ring-opening polymerization (ROP) of ε-caprolactone and rac-lactide (rac-LA). Controlled experiments reveal that {[3a]Al(μ2-OCH2Ph)}2 is competent in living polymerization. Kinetic studies indicate that [3a]AlMe, in the presence of benzyl alcohol, catalyzes ROP of rac-LA at a rate faster than [3b]AlMe and [2a]AlMe(THF) by a factor of 1.8 and 23.6, respectively, highlighting the profound reactivity enhancement in ROP catalysis by varying the P-substituents of these biphenolate complexes of aluminum.

Tuning the H-bond donicity boosts carboxylic acid efficiency in ring-opening polymerization

H-bond donor (HBD) and base co-catalysis achieved great success in ring-opening polymerization (ROP). Parallel H-bond donor and Brønsted acid (HBD–BA) cocatalysis has been scarcely explored in ROPs. In developing the HBD–BA catalysis in to versatile toolbox for ring-opening polymerizations of wider scope and better control, tunable HBDs including boronate pinacol ester urea (BU), urea (U), and thiourea (TU) were evaluated in cooperation with trifluoroacetic acid (TFA) in HBD–BA catalytic mode. Each of the HBD–TFA co-catalyst promoted ROPs of δ-valerolactone (VL) and ε-caprolactone (CL) successfully. The catalytic performances of the HBD–TFA on the HBD part was in an order of BU > U > TU to their corresponding ROPs of VL and CL. The turnover frequencies of the catalyzed ROPs of VL and CL by BU–TFA was twice as that of TFA. The ROPs afforded homopolymers with predicted molecular weights (PVL, Mn,NMR = 2.51–9.92 kg mol−1; PCL, Mn,NMR = 2.51–11.1 kg mol−1) and narrow dispersities (PVL, Đ ≤ 1.16; PCL, Đ ≤ 1.18) by ratios of monomer to initiator from 20 to 100. The obtained polymers were analyzed by 1H NMR, 13C NMR, and MALDI-ToF MS, the results indicated the high chain-end fidelity. Chain extension experiments were conducted by a first ROP of VL/CL and second ROP of CL/VL with precise molecular weights (from 2.98 kg mol−1 to 6.15 kg mol−1) and narrow dispersities below 1.18. The kinetics plots showed a distinct first order relationship between ln([VL]0/[VL]) versus the reaction time, it indicated the controlled nature of the catalytic ROP. NMR titrations supported the proposed mechanism that HBD associated with TFA and promoted the cationic polymerization.

From Zn(C6F5)2 to ZnEt2‐based Lewis Pairs: Significantly Improved Catalytic Activity and Monomer Adaptability for the Ring‐opening Polymerization of Lactones

AbstractIn this contribution, the structure‐reactivity relationships of ZnR2/DMAP (R=C6F5, C6H5 and C2H5) Lewis pairs in ring‐opening polymerization (ROP) of lactones were investigated by crystallographic analysis, density functional theory (DFT) calculations and kinetic studies. With decrease of ZnR2 Lewis acidity, the interaction between ZnR2 and DMAP weakens and the dissociation of ZnR2⋅2DMAP Lewis adducts become easier, which facilitates the activation of cyclic ester monomers. Thus, the ZnEt2/DMAP Lewis pair, bearing weakest interaction between Lewis acid and Lewis base, exhibits high catalytic activity and broad monomer adaptability. ZnEt2⋅2DMAP can convert lactide (LA) rapidly into polylactide (PLA) even at room temperature. Furthermore, a wide range of cyclic esters can also be polymerized using this dual catalyst, from small lactones such as β‐butyrolactone (β‐BL), δ‐valerolactone (δ‐VL) and ϵ‐caprolactone (ϵ‐CL) to the strainless macrolactone. The optimal reaction pathway, key species and active species in the ZnEt2⋅2DMAP catalytic ROP of LA were figured out by DFT calculations. The results clearly indicated that a DMAP‐LA exchange was necessary for activation of monomer, and the single molecular initiation is preferred. Meanwhile, the cyclic active species is more stable than the linear analogues, in which DMAP and ZnEt2 bond with each polymer chain end respectively and ZnEt2 interact with DMAP. The DFT calculation gives an account for the formation of the cyclic polyester in the ROP of LA by ZnR2‐based Lewis pairs.

Crystalline CO2 -Based Aliphatic Polycarbonates with Long Alkyl Chains.

Carbon dioxide (CO2 ) is an easily available, renewable carbon source and can be utilized as a comonomer in the catalytic ring-opening polymerization of epoxides to generate aliphatic polycarbonates. Dodecyl glycidyl ether (DDGE) is copolymerized with CO2 and propylene oxide (PO) to obtain aliphatic poly(dodecyl glycidyl ether carbonate) and poly(propylene carbonate-co-dodecyl glycidyl ether carbonate) copolymers, respectively. The polymerization proceeds at 30°C and high CO2 pressure utilizing the established binary catalytic system (R,R)-Co(salen)Cl/[PPN]Cl. The copolymers with varying DDGE:PO ratios are characterized via NMR, FT-IR spectroscopy, and SEC, exhibiting high molecular weights between 11400 and 37900 g mol-1 with dispersities (Ð=M w /M n ) in the range of 1.37-1.61. Copolymers with T g s of -11°C or T m s from 5 to 15°C and thermal decomposition >200°C depending on the comonomer ratio, are obtained as determined by differential scanning calorimetry/TGA.