Synthesis Of Polycarbonates Research Articles

Methanolysis of Polycarbonate Waste as a Method of Regenerating Monomers for Polycarbonate Synthesis

The factors affecting the methanolysis of polycarbonates catalyzed by sodium methylate are studied. The conversion rate increases with an increase in the basic properties of solvents; the rate of methanolysis depending on the amount of solvent (tetrahydrofuran) is described by an extreme dependence. Changes in sodium methylate concentration and temperature have a small effect on the methanolysis of polycarbonates.

Synthesis of Functionalized Cyclic Carbonates through Commodity Polymer Upcycling.

Functionalized cyclic carbonates are attractive monomers for the synthesis of innovative polycarbonates or polyurethanes for various applications. Even though their synthesis has been intensively investigated, doing so in a sustainable and efficient manner remains a challenge. Herein, we propose an organocatalytic procedure based on the depolymerization of a commodity polymer, bisphenol A based polycarbonate (BPA-PC). Different carbonate-containing heterocycles are obtained in good to excellent yields employing BPA-PC as a sustainable and inexpensive source of carbonate, including functionalized six-membered cyclic carbonates.

Update and Challenges in Carbon Dioxide-Based Polycarbonate Synthesis.

The utilization of carbon dioxide as a comonomer to produce polycarbonates has attracted a great deal of attention from both industrial and academic communities because it promises to replace petroleum-derived plastics and supports a sustainable environment. Significant progress in the copolymerization of cyclic ethers (e.g., epoxide, oxetane) and carbon dioxide has been made in recent decades, owing to the rapid development of catalysts. In this Review, the focus is to summarize and discuss recent advances in the development of homogeneous catalysts, including metal- and organo-based complexes, as well as the preparation of carbon dioxide-based block copolymer and functional polycarbonates.

Introducing the reversible chemistry of CO2with diols mediated by organic superbases into polycarbonate synthesis

The reversible reaction of CO2with alcohols mediated by organic superbases was firstly developed to be a toolbox for capturing CO2into polymerizable carbonate monomers applicable for thiol–ene click and ADMET polymerization to produce new libraries of polycarbonates.

Synthesis of bioderived polycarbonates with adjustable molecular weights catalyzed by phenolic-derived ionic liquids

Phenolic ionic liquid structure can be designed readily to control the molecular weight of isosorbide-derived polycarbonates.

One-pot synthesis of bio-based polycarbonates from dimethyl carbonate and isosorbide under metal-free condition

A synthetic strategy for bio-based polycarbonate was developed via one-pot polymerization of renewable monomer isosorbide and dimethyl carbonate using eco-friendly organo-catalysts.

Efficient synthesis of bio-derived polycarbonates from dimethyl carbonate and isosorbide: regulating exo-OH and endo-OH reactivity by ionic liquids

An eco-compatible route to polycarbonates with various molecular weights has been developed by employing ionic liquids that activate monomers.

Synthesis of terpyridine-containing polycarbonates with post polymerization providing water-soluble and micellar polymers and their metal complexes

Carbon dioxide based polymers synthesized from the metal-catalysed copolymeriation of epoxides and CO2 containing the terpyridine ligand as an end group are reported.

Monomodal Ultrahigh-Molar-Mass Polycarbonate Homopolymers and Diblock Copolymers by Anionic Copolymerization of Epoxides with CO2

Whatever the chemistry used for the synthesis of aliphatic polycarbonates, in particular, those of high molar mass, the adventitious presence of water leads to bimodal GPC traces and affords polycarbonate samples of uncontrolled and unpredictable molar masses. It appears that among all reagents used in the copolymerization of CO2 and epoxides, CO2 is the most difficult one to dry. To address this issue, triisobutylaluminum (TiBA) was employed in this work to dry CO2 through a bubbling method; its drying capability was investigated in the context of the copolymerization of CO2 with epoxides initiated by onium chloride in the presence of triethylborane (TEB). It was then compared to the efficiency of other already reported drying agents such as phosphorus pentoxide, molecular sieves and commercially available CO2 purifiers. With TiBA-dried CO2, its copolymerizations respectively with propylene oxide (PO) and cyclohexene oxide (CHO) could be successfully achieved in a wide range of degrees of polymerization (DP), with the value of DP as high as 16000. Diblock copolymers poly(propylene carbonate-b-cyclohexene carbonate) (PPC-b-PCHC) could also be prepared through sequential addition of epoxide monomers. The polycarbonates obtained under the conditions were all well-defined as characterized by NMR, GPC, triple detector-GPC, and differential scanning calorimetry (DSC).

Zirconium (IV) Acetylacetonate: Ring-Opening Initiator Mediating One-Step Synthesis of Biodegradable Polyacids

Biodegradable polyacid is obtained in one-step ring-opening polymerization (ROP) of carboxylic-acid-functionalized six-membered cyclic carbonate mediated with zirconium (IV) acetylacetonate. Exemplary copolymers with L,L-lactide are described as well. Moreover, zirconium (IV) acetylacetonate is found to be active catalyst of trimethylene carbonate (TMC) ROP in presence of carboxylic acid yielding PTMC end-capped with the acid derivative. Polymerization mechanism is hypothesized demonstrating possibilities of the method in work-saving polycation synthesis and one-step method of conjugate synthesis of well-known biocompatible polyesters and polycarbonates.

Organotin Polymers for the Control of Pancreatic Cancer

Pancreatic cancer is the fourth leading cause of death in the USA. Treatment is seldom successful. A wide variety of organotin polymers exhibit good inhibition of human pancreatic cancer cell lines AsPC-1 and PANC-1. The AsPC-1 is an adenocarcinoma pancreatic cell line and PANC-1 which is an epithelioid carcinoma pancreatic cell line. Synthesis is rapid employing commercially available reactants and the interfacial polymerization that is employed in the commercial synthesis of aramids and polycarbonates.

Synthesis of high-molecular weight isosorbide-based polycarbonates through efficient activation of endo-hydroxyl groups by an ionic liquid

A high-molecular weight bio-based polycarbonate was successfully synthesized by breaking the hydrogen bond of endo-OH group using an ionic liquid.

Synthesis of fluorescent polycarbonates with highly twisted N,N-bis(dialkylamino)anthracene AIE luminogens in the main chain.

A synthetic route to embed aggregation-induced-emission-(AIE)-active luminophores in polycarbonates (PCs) in various ratios is reported. The AIE-active monomer is based on the structure of 9,10-bis(piperidyl)anthracene. The obtained PCs display good film-forming properties, similar to those observed in poly(bisphenol A carbonate) (Ba-PC). The fluorescence quantum yield (Φ) of the PC with 5 mol% AIE-active monomer was 0.04 in solution and 0.53 in solid state. Moreover, this PC is also miscible with commercially available Ba-PC at any blending ratio. A combined analysis by scanning electron microscopy and differential scanning calorimetry did not indicate any clear phase separation. These results thus suggest that even engineering plastics like polycarbonates can be functionalized with AIE luminogens without adverse effects on their physical properties.

En route to CO2-containing renewable materials: catalytic synthesis of polycarbonates and non-isocyanate polyhydroxyurethanes derived from cyclic carbonates.

Combining CO2-chemistry with biomass conversion allows renewable polymeric materials including polycarbonates and polyhydroxyurethanes (PHUs) to be generated. The demand for robust materials with modular properties that can be prepared on an industrial scale is important and, to date, the most important polymeric materials are derived from petrochemicals. These materials inevitably result in CO2 emissions, and therefore making robust materials from renewable sources will contribute to a more sustainable society. An attractive way to address this challenge is to combine biomass transformations with CO2-fixation and material science. An identified target that combines all three aspects involves the preparation of PHUs (or non-isocyanate polyurethanes, NIPUs) via the polymerization of fully renewable cyclic carbonates derived from biomass and CO2 with a diamine compound that can also been derived from biomass sources. In this review, we critically analyze the progress in catalyst development for the efficient transformation of epoxides and CO2 to cyclic carbonates and polycarbonates. We also discuss the synthesis of PHUs from cyclic carbonates and diamines (not restricted to fully renewable compounds), including challenges in regiocontrol and biodegradability, as well as the role catalysts play in the synthesis of these polymers.

Effect of dihalides on the polymer linkages in the Cs2CO3-promoted polycondensation of 1 atm carbon dioxide and diols

Synthesis of biodegradable polycarbonates directly from carbon dioxide and diols has seen renewed interest. In the present report, the effect of a series of organic dihalides (CH2X2 and (CHX)2, where X = Cl, Br, and I) in the Cs2CO3-promoted copolymerization of 1 atm CO2 with diols has been studied. Structural analysis of the resultant polymers/oligomers by spectroscopic techniques reveals that a variety of main chain linkages can be obtained, depending on the dihalides used. Specifically, the methylene units from dibromomethane (DBM) are incorporated into the products as carbonate and ether linkages, and the methylene units from diiodomethane (DIM) are incorporated mainly as the ether linkage and without much CO2 incorporation. In comparison, all dihaloethanes examined lead to clean formation of alternating polycarbonates incorporating both the ethylene units from dihaloethanes and the diol units, and the halide is identified as the end group. The mechanistic pathways and the relative activity of the key intermediates are discussed in light of these results.

1,3-Propanediol and its Application in Bio-Based Polyesters for Resin Applications

Polyester resins are important raw materials for a myriad of applications especially in the field of coatings and radical curing polymers, such as wood and powder coatings, molding compounds, and UV-curing applications. In addition, polyols derived from polyester resins are precursors for the synthesis of polyurethanes and polycarbonates. Besides dicarboxylic acid, diols are used as monomers in these polyesters. To date most of the diols utilized are derived from petrochemical feedstock. To increase the bio-based content of polyester resins, novel diols derived from renewable resources are of special interest. In this respect, 1,3-propanediol has drawn considerable attention over the last years. It is accessible via microbial fermentation of glucose from starch at a competitive price in sufficient amounts. Therefore, 1,3-propanediol could be a valuable alternative to petrochemical diols, such as 1,6-hexanediol and neopentylglycol, which are currently used as diols in most resin applications. This article gives a brief overview over the utilization of 1,3-propanediol in high molecular weight polyesters for plastic application followed by a more detailed discussion of the most relevant work in the field of polyester resins derived from 1,3-propanediol.

Across the Board: Arjan Kleij.

In this series of articles, the board members of ChemSusChem discuss recent research articles that they consider of exceptional quality and importance for sustainability. This entry features Prof. Arjan W. Kleij, who discusses the use of terpenes as raw materials for the synthesis of biobased polyesters and polycarbonates, and the opportunities and challenges that lie ahead for these renewable polymers in the area of material science, trying to meet the requirements of a circular economy.

Theoretical Mechanistic Investigation into Metal-Free Alternating Copolymerization of CO2 and Epoxides: The Key Role of Triethylborane

The copolymerization of carbon dioxide (CO2) and epoxides has received much attention during the past decades for the production of aliphatic polycarbonates. Remarkably, the green synthesis of polycarbonates was recently demonstrated by copolymerization of CO2 with epoxides under metal-free conditions. In this work, the reaction mechanism of this highly selective polymerization was further investigated using DFT calculations. Four steps were studied: step I describes the epoxide ring-opening by the chloride anion in the presence of the Lewis acid triethylborane (TEB); step II is related to the subsequent insertion of CO2; step III corresponds to the alternating insertion of an epoxide facilitated by TEB; step IV is characterized by the leaving of TEB followed by a new round of polymerization. The high selectivity to form alternating polycarbonates and the suppression of backbiting and homopolymerization that respectively generate cyclic carbonates and polyethers were confirmed by the difference of energy ...

Direct electrochemical generation of organic carbonates by dehydrogenative coupling.

Organic carbonates are an important source for polycarbonate synthesis. However, their synthesis generally requires phosgene, sophisticated catalysts, harsh reaction conditions, or other highly reactive chemicals. We present the first direct electrochemical generation of mesityl methyl carbonate by C–H activation. Although this reaction pathway is still challenging concerning scope and efficiency, it outlines a new strategy for carbonate generation.

Synthesis of CO2-derived polycarbonates with high glass transition temperatures

To synthesize CO2-derived polycarbonates with high Tg values, epoxides having rigid and bulky 2-norbornyl or 1-adamantyl substituents were selected as comonomers. The alternating copolymer obtained from 1-adamantylethylene oxide showed a Tg above 150 °C. This is the highest Tg among those observed for alternating copolymers obtained from CO2 and a terminal epoxide. To synthesize CO2-derived polycarbonates with high Tg values, epoxides having rigid and bulky 2-norbornyl or 1-adamantyl substituents were selected as comonomers. The alternating copolymer obtained from 1-adamantylethylene oxide showed a Tg above 150 °C. This is the highest Tg among those observed for alternating copolymers obtained from CO2 and a terminal epoxide.