Polymers from sugars: cyclic monomer synthesis, ring-opening polymerisation, material properties and applications

Sustainable thermoplastic elastomers derived from block copolymers of syndiotactic poly(3-hydroxybutyrate) and poly((−)-menthide) were synthesized via yttrium-mediated ring-opening polymerization.

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Large, Rapid Swelling of High-cis Polydicyclopentadiene Aerogels Suitable for Solvent-Responsive Actuators

Polymers ◽

10.3390/polym12051033 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1033 ◽

Cited By ~ 1

Author(s):

Despoina Chriti ◽

Grigorios Raptopoulos ◽

Benjamin Brandenburg ◽

Patrina Paraskevopoulou

Keyword(s):

Molecular Structure ◽

Organic Solvents ◽

Catalytic System ◽

Chemical Sensors ◽

Material Properties ◽

Open Porosity ◽

Ring Opening ◽

Chemical Structure ◽

Diffusion Distance ◽

Metathesis Polymerization

High-cis polydicyclopentadiene (PDCPD) aerogels were synthesized using ring opening metathesis polymerization (ROMP) of dicyclopentadiene (DCPD) with a relatively air-stable ditungsten catalytic system, Na[W2(μ-Cl)3Cl4(THF)2]·(THF)3 (W2; (W3W)6+, a′2e′4), and norbornadiene (NBD)as a co-initiator. These aerogels are compared in terms of chemical structure and material properties with literature PDCPD aerogels obtained using well-established Ru-based alkylidenes as catalysts. The use of NBD as a co-initiator enhances the degree of crosslinking versus the more frequently used phenylacetylene (PA), yielding materials with a controlled molecular structure that would persist solvent swelling. Indeed, those PDCPD aerogels absorb selected organic solvents (e.g., chloroform, tetrahydrofuran) and swell rapidly, in some cases up to 4 times their original volume within 10 min, thus showing their potential for applications in chemical sensors and solvent-responsive actuators. The advantage of aerogels versus xerogels or dense polymers for these applications is their open porosity, which provides rapid access of the solvent to their interior, thus decreasing the diffusion distance inside the polymer itself, which in turn accelerates the response to the solvents of interest.

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Ring-opening copolymerization (ROCOP): synthesis and properties of polyesters and polycarbonates

Chemical Communications ◽

10.1039/c4cc10113h ◽

2015 ◽

Vol 51 (30) ◽

pp. 6459-6479 ◽

Cited By ~ 278

Author(s):

Shyeni Paul ◽

Yunqing Zhu ◽

Charles Romain ◽

Rachel Brooks ◽

Prabhjot K. Saini ◽

...

Keyword(s):

Ring Opening ◽

Feature Article

This feature article highlights the opportunities presented by ring-opening copolymerization (ROCOP) as a controlled route to prepare polyesters and polycarbonates.

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Ring-opening polymerization

Chemistry Teacher International ◽

10.1515/cti-2020-0028 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Stanislaw Penczek ◽

Julia Pretula ◽

Stanislaw Slomkowski

Keyword(s):

Ring Opening ◽

Ring Opening Polymerization ◽

Monomeric Unit ◽

Industrial Scale ◽

Cyclic Ethers ◽

Basic Information ◽

Cyclic Monomer ◽

Cyclic Nitrogen ◽

Sulfur Containing ◽

Nitrogen Phosphorus

Abstract Ring-opening polymerization is defined by IUPAC (Penczek, S., Moad, G. (2008). Glossary of the terms related to kinetics, thermodynamics, and mechanisms of polymerization. (IUPAC Recommendations 2008), Pure and Applied Chemistry, 80(10), 2163–2193) as (cit.) “Ring-opening polymerization (ROP): Polymerization in which a cyclic monomer yields a monomeric unit that is either acyclic or contains fewer rings than the cyclic monomer”. The large part of the resulting polymerizations is living/controlled; practically all belong to chain polymerizations. After the introduction, providing basic information on chain polymerizations, the paper presents the concise overview of major classes of monomers used in ROP, including cyclic ethers, esters, carbonates, and siloxanes as well as cyclic nitrogen, phosphorus, and sulfur containing monomers. There are discussed also thermodynamics, kinetic polymerizability, and major mechanisms of ROP. Special attention is concentrated on polymers prepared by ROP on industrial scale.

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Enhanced Anticancer Efficacy of Chemotherapy by Amphiphilic Y-Shaped Polypeptide Micelles

Frontiers in Bioengineering and Biotechnology ◽

10.3389/fbioe.2021.817143 ◽

2021 ◽

Vol 9 ◽

Author(s):

Cong Hua ◽

Yi Zhang ◽

Yuanhao Liu

Keyword(s):

Self Assembly ◽

Ring Opening ◽

Primary Treatment ◽

Ring Opening Polymerization ◽

Chemotherapeutic Agents ◽

Treatment Modalities ◽

Cyclic Monomer ◽

Poly Ethylene Glycol ◽

Anticancer Efficacy ◽

Poly Ethylene

Although the treatment modalities of cancers are developing rapidly, chemotherapy is still the primary treatment strategy for most solid cancers. The progress in nanotechnology provides an opportunity to upregulate the tumor suppression efficacy and decreases the systemic toxicities. As a promising nanoplatform, the polymer micelles are fascinating nanocarriers for the encapsulation and delivery of chemotherapeutic agents. The chemical and physical properties of amphiphilic co-polymers could significantly regulate the performances of the micellar self-assembly and affect the behaviors of controlled release of drugs. Herein, two amphiphilic Y-shaped polypeptides are prepared by the ring-opening polymerization of cyclic monomer l-leucine N-carboxyanhydride (l-Leu NCA) initiated by a dual-amino-ended macroinitiator poly(ethylene glycol) [mPEG-(NH2)2]. The block co-polypeptides with PLeu8 and PLeu16 segments could form spontaneously into micelles in an aqueous solution with hydrodynamic radii of 80.0 ± 6.0 and 69.1 ± 4.8 nm, respectively. The developed doxorubicin (DOX)-loaded micelles could release the payload in a sustained pattern and inhibit the growth of xenografted human HepG2 hepatocellular carcinoma with decreased systemic toxicity. The results demonstrated the great potential of polypeptide micellar formulations in cancer therapy clinically.

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Grain boundary segregation in metals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130651 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1204-1205

Author(s):

C.L. Briant

Keyword(s):

Fracture Surface ◽

Grain Boundary ◽

Grain Boundaries ◽

Material Properties ◽

Electron Spectroscopy ◽

High Vacuum ◽

Boundary Segregation ◽

Grain Boundary Segregation ◽

Local Concentration ◽

The One

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.

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Relationships Between Grain Boundary Structure and Material Properties

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600001550 ◽

1980 ◽

Vol 38 ◽

pp. 366-369

Author(s):

Brian Ralph ◽

Barlow Claire ◽

Nicola Ecob

Keyword(s):

Grain Boundary ◽

Material Properties ◽

Main Property ◽

Grain Structure ◽

Boundary Structure ◽

Grain Boundary Structure ◽

Property Changes

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.

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Amino-functional polyethers: versatile, stimuli-responsive polymers

Polymer Chemistry ◽

10.1039/d0py00466a ◽

2020 ◽

Vol 11 (24) ◽

pp. 3940-3950 ◽

Cited By ~ 2

Author(s):

Patrick Verkoyen ◽

Holger Frey

Keyword(s):

Ring Opening ◽

Review Article ◽

Stimuli Responsive ◽

New Class ◽

Stimuli Responsive Polymers ◽

Responsive Polymers

Amino-functional polyethers have emerged as a new class of “smart”, i.e. pH- and thermoresponsive materials. This review article summarizes the synthesis and applications of these materials, obtained from ring-opening of suitable epoxide monomers.

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