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In this work we successfully synthesized degradable microgels based on poly(N-vinylcaprolactam) (PVCL) with hydrophobic pockets for the uptake/release of poorly water-soluble molecules. The degradability as well as the presence of hydrophobic pockets in the microgel structure are ensured by incorporation of a star-shaped acrylate-functionalised poly(e-caprolactone) (starPCL) crosslinkers. Microgels with variable amount of star PCL crosslinker, narrow size distribution and a hydrodynamic radius of 200–400 nm were obtained by miniemulsion polymerisation. The microgel size and size distribution was characterised by means of dynamic light scattering (DLS), field emission scanning electron microscopy (FESEM) and sedimentation analysis. The obtained microgels undergo enzymatic degradation in aqueous medium as evidenced by DLS, nuclear magnetic resonance (NMR) and FESEM. Additionally, the uptake of hydrophobic molecules like the dye Nile-Red (model system) and the drug Ibuprofen into the starPCL-based microgels was proven by ultraviolet–visible spectroscopy (UV/Vis). The experimental data indicate that the solubilisation ability of microgels can be regulated by the amount of crosslinker in the microgel structure.

In this work we focused on synthesis and characterization of aqueous poly(N-vinylcaprolactam) (PVCL) microgels decorated with oligoglycidol-macromonomers. Oligoglycidol macromonomers with styrene or acrylate polymerisable group and tunable length of the oligoglycidol chain (6, 12 and 50 glycidol units) were synthesized. The microgels were synthesized by aqueous precipitation copolymerization of N-vinylcaprolactam and oligoglycidol macromonomers in presence of crosslinking agent. The length of the oligoglycidol chain and the concentration of macromonomer in the reaction mixture were varied to investigate a direct influence on the polymerization rate and microgel properties. Synthesized microgels exhibit radii from 50 to 350 nm and show temperature-responsive properties. We demonstrate that oligoglycidol macromonomers are localized predominantly on the microgel surface. This ensures excellent colloidal stabilisation of oligoglycidol-decorated microgels in aqueous solutions and functionalization of microgels with hydroxyl groups, which can be potentially used for further post-modification reactions.

The functionalization of polymers with phosphorus based reagents is of great interest in the preparation of polymeric materials. In this work we present a straightforward method for the introduction of pendant diethyl phosphate groups into polyglycidol by reaction with diethyl chlorophosphate. The degree of functionalization was controlled by the ratio of the phosphorus reagent to the hydroxyl groups attached to the polyether backbone. Resulting polymers were characterized by 1H, 13C, 31P {1H} NMR spectroscopy, FTIR spectroscopy and SEC analysis. The removal of one and both ethyl groups of the phosphate ester was selectively achieved by reaction with sodium iodide or bromotrimethylsilane, respectively.

A highly stable benzimidazolylidene based N-heterocyclic carbene (NHC) ruthenium catalyst was prepared starting with readily accessible starting materials. Under inert gas atmosphere and in air the catalyst showed high activity for the direct synthesis of esters from primary alcohols and of amides from primary alcohols and amines. Di-, tri-, and oligo-amides were obtained by using specific starting materials.

Glycerol and d , l -homocysteine thiolactone – two bio-based building blocks – were used to prepare a bis-cyclic AA′ monomer (or coupler) with an ethylene carbonate and a thiolactone ring linked by an O-methyl urethane spacer. On reaction of this monomer with diamines at 70 °C poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups are produced in one step. Monodisperse diamines of low molecular weight (MW), monodisperse amino telechelic poly(ethylene oxide) (MW = 897.10) and polydisperse amino telechelic polytetrahydrofuran (Mn = 1100) were used as amine building blocks. By reaction of the coupler with diamines at room temperature only the thiolactone ring is converted. Consequently, a bis(ethylene carbonate) bis(thiol) is obtained if one equivalent diamine is reacted with two equivalents of coupler. Reaction of this intermediate with a second diamine leads to poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups and alternating amine building blocks. Post-polymerization modification of thiol side groups leads to polymers with designed properties. The microstructure of the obtained polymers was proven by 1H NMR and Raman spectroscopy; the molecular weights were determined by size exclusion chromatography.

A new synthetic approach to thiol functional, well-defined amphiphilic block copolymers, which can be used to prepare multifunctional polymers and polymeric nanoparticles, is presented. Starting with a hydrophilic macroRAFT transfer agent and hydrophobic (meth)acrylate monomers that possess protected thiol groups, amphiphilic block copolymers are prepared in high yield. It is proven that the protected thiol groups in the monomer do not interfere with the RAFT polymerization process. Polymers with defined molecular weight, narrow polydispersities (PDI

Linear aliphatic polyesters having pendant hydroxyl groups were successfully synthesised by polycondensation using scandium triflate as catalyst. A first set of samples was prepared starting with hexane-, octane-, decane-, and dodecanediol and l -malic acid as hydroxyl functional dicarboxylic acid, on the one hand, and succinic acid as non-functional analogue, on the other. A second set of samples was prepared starting with different hydroxytelechelic oligo(e-caprolactone)s, synthesised in a ring opening polymerisation (ROP) initiated by hexanediol using the same catalyst, and reacted with l -malic acid or succinic acid, respectively. The successful reaction was confirmed by nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). The thermal properties of both types of polyesters – with and without pendant hydroxyl groups – were analysed by differential scanning calorimetry (DSC). While all polyesters based on succinic acid are highly crystalline, for the polyesters based on l -malic acid the crystallinity depends on the concentration of pendant hydroxyl groups and on the microstructure. Hence, the influence of the hydroxyl group enables to tailor the crystallinity.

Isocyanate homo telechelic poly(methyl methacrylate-co-allyl methacrylate)s were prepared and used as soft segments for thermoplastic polyurethanes. Copolymerization of allyl methacrylate and methyl methacrylate by RAFT leads to selective conversion of the methacrylate C,C double bonds, leaving the allyl groups in the polymer side chain intact. A hetero telechelic MMA/AMA copolymer (Het-PMMA/AMA, molar ratio of MMA/AMA = 10/1) with a carboxylic acid and a dithiobenzoate terminus was obtained using 4,4-azobis(4-cyano pentanoic acid) as initiator and 4-cyano pentanoic acid dithiobenzoate as chain transfer agent. In a second reaction step the dithiobenzoate terminus is converted to carboxylic acid groups by a radical exchange reaction. The carboxylic acid homo telechelic statistical copolymer (Ca-Hot-PMMA/AMA) is converted quantitatively by reaction with hexamethylene diisocyanate in order to form isocyanate homo telechelic copolymer (Is-Hot-PMMA/AMA). Last the obtained soft segments were used for polyurethane synthesis. The well-defined polymer structures are characterized by SEC, Raman, and 1H NMR spectroscopy.

Poly-N-acetyllactosamines (poly-LacNAc, [−3Gal(β1–4)GlcNAc(β1−]n) are terminal glycan structures present in glycoproteins and glycolipids. Their biological functions as ligands for galectins and as carriers of glycan epitopes are well documented. In the present paper we have characterized six novel functionalized β- d -GlcNAc derivatives, including aglyca of varying hydrophobicity and molecular weight, as substrates for recombinant human β1,4 galactosyltransferase 1 (β4GalT-1). The sugar derivatives carry short or long amino- or azide-terminated linker molecules for further modification or immobilization. The linker chemistry had an impact on enzyme kinetics and enzymatic syntheses of N-acetyllactosamine derivatives (LacNAc, Gal(β1–4)GlcNAc(β1-R). The combination of β4GalT-1 with bacterial β1,3-N-acetylglucosaminyltransferase (β3GlcNAc-T) resulted in the preparative syntheses of LacNAc oligomers with up to three LacNAc repeating units. All products were characterized by NMR and MS. The obtained LacNAc glycans were immobilized onto microtiter plates and their efficiency of binding of fungal galectin CGL2 was determined.

Several industrial processes based on lipase catalysis have been established. However, since there are still a vast number of catalytic processes that lack a suitable enzyme, the discovery of new biocatalysts is required to fulfil this purpose. The potential of using the medium-chain-length (mcl)-PHA depolymerase from Pseudomonas fluorescens GK13 in anhydrous media to catalyze ester-forming reactions has been investigated and compared with that of Novozyme 435. The mcl-PHA depolymerase catalyzes the ring-opening polymerization of racemic β-butyrolactone (β-BL), l - and d -lactide (LLA, DLA) with high yield resulting in low molecular weight polymers. On the other hand, ɛ-caprolactone and pentadecalactone, which show high polymerizability using Novozyme 435 as catalyst, were not polymerized by mcl-PHA depolymerase. Besides, the activity of mcl-PHA depolymerase toward transesterification and esterification of ethyl-3-hydroxyoctanoate, lauric acid, ( R , S )-β-BL, LLA and DLA has been studied.

The synthesis and modification of thiol functionalized poly(meth)acrylates using a straightforward reaction concept that consists of an enzymatically catalyzed monomer synthesis, free radical polymerization and post-polymerization modification is presented. The well-known enzymatic transacylation of methyl acrylate and methyl methacrylate that runs under mild and environmentally friendly conditions was used to synthesize thiol protected acrylic and methacrylic monomers. Upon free radical polymerization and subsequent removal of protection groups, polymers with pendant thiol groups are obtained, which, in turn, can react in situ with Michael acceptors to form thiol-ene reaction products. The exceptional advantage of the proposed method is that upon removal of the enzyme from the monomer mixture, the polymerization, deprotection of thiols and subsequent Thio-Michael-type addition reaction can be conducted in one pot without purification of the intermediate products. Furthermore, the different reactivities of acetyl and benzoyl protection groups in lipase catalyzed reactions are discussed.

Starting with asymmetric A,A′-carbonate couplers A1–A4 via substitution reaction with primary amines at low temperatures (0–25 °C) followed by addition reaction with primary amines at higher temperatures (60–80 °C), bis(functional) compounds with a free hydroxyl group were prepared. These compounds were used: (i) as initiators for ring-opening polymerization of e-caprolactone; (ii) as substrate for the preparation of an ATRP initiator for MMA polymerization; (iii) as substrate for the preparation of an activated carbonate for grafting of an amine end-functionalized linear polymer (Jeffamine® M1000). Via modifications (i)–(iii), amphiphilic end-functionalized poly(e-caprolactone)s, poly(methyl methacrylate)s, and polyethers were prepared, respectively.

5-Ethyl-5-(((2-oxo-1,3-dioxolan-4-yl)methoxy)methyl)-1,3-dioxan-2-one ( BC56 ) bearing a five- and six-membered ring carbonate was successfully synthesized and characterized. In model reactions it was shown that BC56 reacts selectively with 1 eq. of a primary amine at low temperature, only/mainly the six-membered ring carbonate is converted. Ionic, hydrophilic and hydrophobic amines were used to prepare functional couplers. Reaction of the functional couplers with a second primary amine group under more severe reaction conditions results in a coupling product. Both, polycondensation of BC56 with diamines in a one-step procedure (Procedure A) or in a two-step reaction (Procedure B) yielded poly(hydroxyl urethane) or its oligomers. Different reaction conditions were tested for the synthesis of poly(hydroxyl urethane)s with higher molecular weight. Solvents have the most significant influence to the molecular weight of the resulting polymer. In solvents with low polarity (e.g. THF and CHCl 3 ), polymers with relative high molecular weight ( M ¯ w ≈ 10 , 000 g / mol ) were obtained; in solvents with high polarity (e.g. DMAc and DMF) oligomers ( 2000 M ¯ w 6000 g / mol ) were obtained. Using Procedure B, poly(hydroxyl urethane)s with hydrophobic and hydrophilic alternating diamine groups in backbone were prepared.

Three reactive polymers, poly(para-nitrophenoxycarbonyloxyethyl methacrylate-co-methyl methacrylate) P(p-NPCEMA-co-MMA) [rCoP1], poly(methyl methacrylate-co-butyl methacrylate-co-allyl methacrylate-co-phenoxycarbonyloxyethyl methacrylate) P(MMA-co-BMA-co-AMA-co-PCEMA) [rCoP2] and poly(methyl methacrylate-co-dimethylaminopropyl methacrylate-co-dodecyl methacrylate-co-phenoxycarbonyloxyethyl methacrylate) P(MMA-co-DMAPMA-co-DMA-co-PCEMA) [rCoP3], respectively, were prepared following two synthetic concepts. Following the first concept, p-NPCEMA and PCEMA were prepared starting with commercially available HEMA and were copolymerized via ATRP with MMA, BMA and AMA. According to the second concept phenoxycarbonyloxy decorated polymethacrylates were obtained via polymer analogous reaction of a HEMA containing functional polymethacrylate, P(MMA-co-DMAPMA-co-DMA-co-HEMA) [fCoP], obtained via a cascade reaction of enzymatic transacylation and free radical polymerization. The highly reactive poly(methacrylate)s and silk peptides, hen egg-white lysozyme and Candida antarctica lipase B were used for the preparation of protein/peptide-poly(methacrylate) bioconjugates.

Candida antarctica lipase B (CAL-B, Novozyme 435) catalyzes the transacylation of methyl acrylate and methyl methacrylate with diols and triols in 2-methyl-2-butanol at 50 °C. Under the experimental conditions, up to 70 mol% of the acyl donor methyl acrylate was converted. Methyl methacrylate is the less efficient acyl donor (up to 60 mol%) due to the higher sterical hindrance in the enzymatic transacylation. Under the reaction conditions high yields of the mono-acylated products are obtained, which contain minor amounts of bis(meth)acrylates. In addition it was observed that Novozyme 435 catalyzes regioselectively the acylation of the primary hydroxyl groups. In comparison with the chemical catalyzed route no selectivity was observed for unsubstituted diols. For substituted diols more mono-acylated product was formed in the lipase-catalyzed reaction than in the chemical catalyzed reaction.

Two copolymers, P(PCEMA-co-MMA) and P(t-BMA-block-PCEMA), were prepared via ATRP using 2-(phenoxycarbonyloxy)ethyl methacrylate (PCEMA) as reactive monomer and methyl methacrylate (MMA) or tert-butyl methacrylate (t-BMA) as co-monomers. Alternatively phenoxycarbonyloxy decorated polymethacrylates were obtained via polymer analogous reaction: P(HEMA) was reacted with phenyl chloroformate to yield P(PCEMA). The highly reactive phenoxycarbonyloxy groups were used for polymer analogous reactions with nucleophiles to obtain polymers with ionic/hydrophilic and hydrophobic side groups. Different amines with long alkyl chains or tertiary amine groups were reacted with phenoxycarbonyloxy decorated polymers and subsequently reacted with methyl iodide to obtain amphipathic polymers with bacteriostatic properties.

Well defined linear and 3-, 4-, and 6-arm-star shaped polyglycidols were obtained via anionic ring-opening polymerisation of ethoxyethyl glycidyl ether using 3-phenyl-1-propanol, trimethylolpropane, di(trimethylolpropane, and dipentaerythrite as initiator followed by the removal of the acetal protection group via acid catalysed hydrolysis. The microstructure and architecture of the polymers was proven by NMR spectroscopy, size exclusion chromatography and MALDI-TOF-MS. Multifunctional initiators for the atom transfer radical polymerisation were obtained by esterification of the hydroxyl groups of the polyglycidols with α-bromoisobutyryl bromide. Kinetic studies of the ATRP of tert-butyl acrylate and methyl acrylate revealed a controlled synthesis of linear and multi-arm-star polyglycidols of different architecture grafted with polyacrylate side arms.

Anionic polymerization of EEGE with alkali metal based initiators has been shown to yield polyglycidol with low polydispersity indices for molecular weights up to M n ≈ 30,000. Higher molecular weights have not been obtained due to the occurrence of a chain transfer reaction to the monomer. Chain transfer to the monomer leads to P(EEGE) with an alcohol end group and an allylic alcoholate, which reinitiates the polymerization of EEGE. In the present study, the influence of temperature (in a range from 20 °C to 120 °C) and of different initiating systems, such as 3-phenylpropanol/potassium 3-phenylpropanolate, potassium tert -butoxide and sec -butyllithium/phosphazene base, on the chain transfer reaction is investigated. In all cases, the basicity of the alkoxide at the propagating chain end induces chain transfer. The formation of allylic end groups was evidenced by 1 H NMR spectroscopy.

Alternating poly(amide urethane)s from e-caprolactam, amino alcohols H2N–(CH2)x–OH (x=2–6), and diphenyl carbonate were prepared by polycondensation of α-hydroxy-ω-O-phenylurethanes 4a-e. The degree of oligomerization was adjusted by the conversion. Oligomers with two or three O-phenylurethane end groups and predetermined molecular weight were prepared by polycondensation of the α-hydroxy-ω-O-phenylurethanes 4a-e in the presence of comonomers with O-phenylurethane end groups in a given concentration. In order to prepare oligomers with hydroxyl and carboxyl groups at both chain ends suitable for coupling reactions, chain analogous reactions were performed with amino acids and amino alcohols. The microstructure of the polymers and the nature of end groups was determined by means of 1H NMR spectroscopy and the molecular weights were determined by means of gel permeation chromatography. The poly(amide urethane)s 5a-e prepared are semicrystalline materials with melting points between 150 and 200 °C.

Monofunctional poly(ethylene oxide) macroinitiators with a molecular weight of 2000, 5000, 10 000, 20 000 and bifunctional poly(ethylene oxide) macroinitiators with a molecular weight of 20 000 were used for the atom transfer radical polymerisation (ATRP) of hydroxyethyl methacrylate (HEMA) in ethylene glycol as a solvent. The polymerisation proceeds in a controlled way up to high conversions. The molecular weight of the obtained copolymers increases linearly with conversion. A high rate of polymerisation was observed for the ATRP of HEMA. The effect of the poly(ethylene oxide) moiety on the course of the reaction is limited to solvating effects. The surface analysis of poly(ethylene oxide)/poly(hydroxyethyl methacrylate) block copolymers by means of atomic force microscopy in tapping mode using phase imaging shows phase separated domains with characteristic features related to the volume fraction of the respective blocks.

Monofunctional PEO-macroinitiators (mPEO-F) were prepared from monohydroxyfunctional poly(ethylene oxide)s and 2-chloro-2-phenylacetylchloride. In order to synthesise poly(ethylene oxide)-block-poly(styrene) (PEO-b-PS) the macroinitiators were applied to the atom transfer radical polymerisation (ATRP) of styrene in the bulk. Well-defined block copolymers were obtained with predetermined molecular weight and narrow molecular weight distribution. Kinetic aspects of ATRP of styrene depending on the molecular weight of the macroinitiator are discussed. Surface analysis by means of atomic force microscopy in tapping mode using phase imaging reveals characteristic morphologies as a function of the volume fraction of PEO. The higher the PEO content the more PEO is found at the polymer/air interface. The preparation of the samples has a main impact on the observed morphology. The polymer films are hygroscopic and alter their morphology being exposed to air.

The copolymerization of 5-[(4-fluorophenyl)sulfonyl]-2-fluorobenzoic acid with bis(4-hydroxyphenyl)sulfone in 1,1-dioxothiolane with sodium carbonate as a base results in carboxylated poly(ether sulfone)s. The polycondensation polymerization, however, is associated with partial decarboxylation. Conversely, the copolymerization of 2,5-dihydroxybenzoic acid (hydroquinone carboxylic acid) with bis(4-fluorophenyl)sulfone under identical conditions results in a poly(ether ether sulfone) with quantitative decarboxylation.

The atom transfer radical polymerization (ATRP) of styrene and methyl methacrylate with differently substituted model and macroinitiators was performed, in order to evaluate qualitatively the structural features which affect the efficiency of the initiation step. It was found that substituents which stabilize radicals enhance the dissociation of the halogen atom and lead to high initiation efficiencies of the model initiators and macroinitiators. The phenyl group and the oxycarbonyl group result in the efficient initiators 1a and 3a for the initiation of both styrene and methyl methacrylate. Further, it was shown that the poly(ethylene oxide) moiety in the initiator, because of its low solubility, e.g. in styrene/poly(styrene) mixtures, leads to phase separation that effects the reactivity of the initiating group.

Copolymerization of equimolar amounts of 2,2-dimethyltrimethylene carbonate (DTC) with tetramethylene urea (TeU) results in a copolymer the microstructure of which depends on the reaction conditions and on the catalyst used. With sec-butyllithium, dibutylmagnesium and diethylzinc as a catalyst a nearly alternating copolymer, i.e. a polyurethane, was obtained. With dibutyldimethoxytin, tris(sec-butoxyaluminium), and tetrakis(iso-propoxytitanium) as a catalyst copolymers with carbonate, urea, and urethane groups were obtained.

The dissolution of alkali metal salts, e.g. LiClO 4 , LiCF 3 SO 3 , NaSCN, NaI, NaCF 3 SO 3 and KSCN in poly(2,2-dimethyltrimethylene carbonate)-block-poly(ethylene oxide)-block-poly(2,2-dimethyltrimethylene carbonate) (PDTC- b -PEO- b -PDTC) results in solid polymeric electrolytes. Depending on the nature of the salt, differential scanning calorimetry (d.s.c.) measurements of the polymer/salt systems reveal that crystalline complexes are obtained with NaI, NaSCN, and LiCF 3 SO 3 . These complexes exhibit characteristic infra-red (i.r.) bands, e.g. at 1106 and 1080 cm −1 for the complex with NaI. X-ray powder diagrams of the polymer/salt complexes show that the original patterns of the salt and the crystalline PEO phase have disappeared in favour of a new pattern for the complex; however, reflections attributed to the crystalline PDTC phase are found to be unchanged. Complexation takes place mainly with the PEO segments of the block copolymer, thus causing a change in the secondary structure of the original PEO helix. The stoichiometry of the polymer/salt complexes is 3 1 (EO repeating units/metal cation). The highest value of the alternating current conductivity was obtained for LiCF 3 SO 3 as the salt component, with values of σ = 10 −4 S cm −1 at 60°C being obtained at concentrations of 5 to 10 mol% (based on the EO repeat units). From temperature dependent conductivity measurements it was concluded that above the glass transition temperature the ionic conductivity of the sodium salt systems follows an Arrhenius behaviour, while the lithium and potassium salt systems follow a Vogel-Tammann-Fulcher behaviour.

Alkalimetal salts (Li+, K+) and metal-free salts ([(CH3)2N]3S+, Bu4N+) of hydroxytelechelic poly(THF) were used as initiators for the anionic ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC). With both systems triblock copolymers were obtained with a monomodal distribution of molecular weights, with one exception. Copolymers with equal length of the poly(DTC) block and increasing molecular weight of the initiating block show the following features: (i) no influence at low molecular weights of the initiator ( M n = 650 ); (ii) plasticizing effect in the range 1000 M n ; (iii) two phase systems at M n > 2600 . The triblock structure of the copolymers was established by degradation of the poly(THF) middle block under acidic conditions with subsequent 1H-NMR and GPC analysis.

The reaction of 2,2-dimethyltrimethylene carbonate (DTC) and ϵ-caprolactam (EClam) in toluene with s-BuLi as initiator leads to cyclic oligomers containing one EClam moiety and n DTC units ( n = 2–10). A mechanism for the formation of the oligomers is proposed.

Insertion polymerization of 2,2-dimethyltrimethylene carbonate (DTC) with initiators based on tetraphenylporphyrin-aluminium (TPPAl-R) results in high yields of poly (2,2-dimethyltrimethylene carbonate) without cyclic oligomers being formed. This indicates that back biting does not take place. The polymerization reaction is slow in methylene chloride or toluene at room temperature; the reaction rate increases with increasing temperature. Tetraphenylporphyrin-alkoxides (TPPAl-OR), the most active initiators for DTC polymerization, from a mixture of DTC and e-caprolactone (ECL) yield a statistical copolymer, indicating poor selectivity towards these monomers. The initiator, however, is well suited for block copolymer synthesis upon stepwise addition of the monomers, e.g. poly (ECL- block -DTC), poly (ethylene oxide- block -DTC) and poly (propylene oxide- block -DTC). The thermal properties of poly (propylene oxide- block -DTC) as a function of composition are reported. Copolymers with a high propylene oxide content show a pronounced glass transition temperature for the polyether block; all copolymers show only one melting transition which is assigned to that of the polycarbonate block.

Alkali metal salts of poly(ethylene glycol)s (PEG) and poly(ethylene glycol) monomethylethers (PEGMe) may be used as initiators for the anionic ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC). The potassium salts of PEG and PEGMe are highly cryptated and lead under the reaction conditions to low block copolymer yields and relatively high yields of cyclic DTC oligomers. The lithium salts, however, lead to high yields of block copolymers of the AB and ABA types, depending on the initiator used—PEGMe or PEG. The properties of the copolymers are strongly dependent on the molar ratio of the repeating units. In ABA triblock copolymers having large B blocks, two melting transitions corresponding to each block are observed, especially upon the second heating. The thermal properties as compared to the homopolycarbonate are not influenced by small PEG blocks; therefore, the dilithium salt of PEG 200 can be considered to be a good bifunctional initiator for the polymerization of DTC. PEG-PDTC block copolymers with equal size of the PDTC block show no difference in the GPC elution volume with THF as solvent when the PEG block increases in size.