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Recently much effort has been devoted to developing drug delivery systems based on macromolecules of three-dimensional structure. In addition to dendrimers which are widely studied, hyperbranched polymers are gaining more and more attention. Among numerous polymeric materials used in drug delivery systems, aliphatic polycarbonates are one of the most interesting ones due to biocompatibility, nontoxic degradation products, and the absence of autocatalytic effect during the degradation process. However, they show poor solubility in supercritical carbon dioxide. This paper describes the synthesis of 5-(4-hydroxybutyl)-1,3-dioxan-2-one and its application for preparation of hyperbranched aliphatic polycarbonates. Linear analogues of the poly(5-(4-hydroxybutyl)-1,3dioxan-2-one) were prepared, too, and the structures were compared by means of 13 C NMR. Ring-opening polymerization of 5-(4-hydroxybutyl)-1,3-dioxan-2-one led to polymers containing solely primary hydroxyl groups which were subsequently reacted with trifluoroacetic anhydride. The phase behavior of fluorinated polymer in supercritical carbon dioxide was explored as a function of concentration and temperature. Modified hyperbranched polycarbonate showed reasonably good solubility in carbon dioxide. It was shown that hyperbranched structure of a polymer facilitate solubility even though the carbonate structural units do not promote solubility in scCO 2 .

Synthesis of oligocarbonate diols from a "green monomer"-dimethyl carbonate-as soft segments for poly(urethane-urea) elastomers Summary-Results from the investigation of a two-step synthesis of oligocarbonate diols from a "green monomer"-dimethyl carbonate (DMC) are presented and discussed. In the first step 1,6-hexanediol or 1,10-decanediol was reacted with DMC to obtain bis(methylcarbonate)hexamethylene (1h) or bis(methylcarbonate)decamethylene (1d), respectively which were further reacted in the next step with appropriate diol at a intended molar ratio to obtain the final product. The solvent-1,4-dioxane-served as a suppressant of the evaporation of both the diol and low molecular weight oligomers, while facilitating the removal of residual amount of methanol and full conversion of methylcarbonate groups. This method allows for the synthesis of oligocarbonate diols without ether linkages containing exclusively terminal hydroxyl groups and of desired molecular weights. It was shown that such oligomerols can be applied for the preparation of poly(urethane-urea) elastomers. The obtained elastomers based on oligocarbonate diols of molecular weights ranging from 1700 to 2700 exhibited very good mechanical properties.

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a Poly(carbonate-urethane-urea)s (PCUU) based on oligocarbonate diols (M n ≈ 2000) with different length of the hydrocarbon chain as soft segments were synthesized and investigated. Carbonate oligomerols were obtained in a two-step method from dimethyl carbonate (DMC) and linear α,ω-diols (1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-dekanediol and 1,12-dodecanediol). Oligo(trimethylene carbonate) diol was synthesized using ring-opening polymerization of trimethylence carbonate. PCUUs were obtained by prepolymer method using isophorone diisocyanate (IPDI) and water as a chain extender. Changes in polymers properties with increase of methylene group number between carbonate linkages were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), tensile strength and hardness measurements. The thermal stability was also analyzed by means of thermogravimetric analysis (TGA). Based on FTIR analysis influence of methylene groups number between carbonate linkages on phase separation and concentration of allophanate and biuret groups in the samples were investigated. The obtained poly(carbonate-urethane-urea)s exhibited very good mechanical properties. Tensile strength and elongation at break were 40 MPa and 400-600%, respectively, depending on the oligocarbonate used.

A challenge in the design of shape‐memory polymers (SMPs) is to achieve high deformability with a simultaneous high shape recovery ratio. Here we explored, whether SMPs featuring large deformation capability and high shape recovery ratios can be created as polymer networks providing two kinds of netpoints based on covalent bonds and physical interactions. As a model system, we selected poly(carbonate‐urea‐urethane)s (PCUUs) synthesized by a precursor route, based on oligo(alkylene carbonate) diols, isophorone diisocyanate (IPDI), and water vapor. The PCUU networks exhibited a one‐way shape‐memory effect (1W‐SME) with programmed strains up to εprog = 1000% whereby they provided excellent shape fixity (92–97%) and shape recovery (≥99%) ratios. The switching temperatures (Tsw) varied between 36 and 65 °C and increased with the increasing molecular weight of the oligo(alkylene carbonate) diol and length of the hydrocarbon chain between the carbonate linkages. Tsw was also influenced by the strain applied during programming (εprog). Poly(carbonate‐urethane)s have been reported to have good biocompatibility and biostability, which in the combination of high‐strain capacity and high Young's modulus makes the obtained PCUUs interesting candidate materials suitable for medical devices such as medical sutures or vascular stents. Copyright © 2016 John Wiley & Sons, Ltd.

Two reaction pathways for synthesis of high molar mass (M w above 50 000 g/mol) aliphatic-aromatic poly(estercarbonate)s were elaborated. Simple organic carbonates such as dimethyl carbonate or propylene carbonate were used as carbonate linkage sources and dimethyl terephthalate as the precursor of ester linkages. 1,4-Butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,10-decanediol were used as diol monomers. To adjust the carbonate units content in the copolymer, solid alkylene bis(methylcarbonate) was used as a semiproduct instead of volatile dimethyl carbonate. In case of usage propylene carbonate as a starting material the process can be carried out in one pot without the need for isolation of the semiproduct. The obtained copolymers based on 1,4-butanediol, containing ca. 50 mol.% of carbonate units exhibited better mechanical strength (37 MPa) than commercially available aliphatic-aromatic copolyester Ecoflex ® keeping the thermal properties at the same level.

Oligocarbonate diols due to their resistance to oxidation and hydrolysis are particularly valuable components of polyurethanes for biomedical applications. It was shown that for their synthesis ''green monomer,'' ethylene carbonate can be used in the reaction with 1,6-hexanediol, instead of usually applied toxic and harmful phosgene. Depending on reaction conditions, besides ester exchange leading to the desired product, competitive etherification is often observed. To optimize the reaction conditions leading to oligocarbonates of high molecular weight without oxyethylene fragments, the method of an experimental design was applied. Such approach enabled the estimation of the influence of reaction temperature, ethylene carbonate to 1,6-hexanediol molar ratio and catalyst (NaCl) concentration on the molar mass of oligocarbonate diol, content of ether bonds and reaction time. Application of central composite method as an experimental design allowed not only to choose the optimal set of conditions, but also the coefficients of the regression equation were interpreted in a chemical way. Oligocarbonate diols obtained under optimal conditions were used for synthesis poly(urethane-urea)s which exhibited very good mechanical properties (tensile strength 45-50 MPa and elongation at break up to 500%). V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: [683][684][685][686][687][688][689][690][691] 2011