Archive for June, 2017

Paper of the month: Structure/property relationships in copolymers comprising renewable isosorbide, glucarodilactone, and 2,5-bis(hydroxymethyl)furan subunits

Polyesters obtained from bio-derived monomers are often used as building blocks with the ultimate aim of meeting consumer demands for high-performance and sustainable materials. To this end, Reineke, Tolman, and Lillie sought to establish how changing the ratio of the sustainable D-glucaro-1,4:6,3-dilactone containing α, ω-diene (GDLU) and isosorbide undecanoate (IU) may influence the thermal, chemical and mechanical properties of the acyclic diene metathesis (ADMET)-derived polymers. The authors synthesized a series of random copolymers consisting of a range of GDLU and IU compositions and fully characterized them by uniaxial tensile testing, small-amplitude oscillatory shear rheology, X-ray scattering, and hydrolytic degradation testing.

 

It was found that small compositional changes have a detrimental impact on their mechanical performance and degradability. In addition, the authors investigated which carbohydrate-based building block was most important in promoting the elasticity and shape-memory abilities of this class of materials. To address this issue, GDL or isosorbide were replaced with a different sustainable diol, 2,5-bis(hydroxymethyl) furan. Studies of the resulting copolymers indicated that GDLU is responsible for imparting both elasticity and shape memory properties. Further, more economical and environmentally-friendly routes for the synthesis of GDLU and IU feedstocks were also explored.

 

Tips/comments directly from the authors:

  1. Acetonitrile appears to be the essential solvent for the scandium triflate-catalyzed esterification of GDL with 10-undecenoic acid anhydride.
  2. 10-Undecenoic acid anhydride can rapidly degrade on wet silica gel. To prevent this, oven dry (120 °C) the silica gel prior to its use and minimize the excess 10-undecenoic acid anhydride used in the reaction.
  3. Due to the hydrolytic instability of GDL and GDL-containing polymers, they should be stored in a vacuum desiccator to protected from moisture to prevent degradation between uses.

 

Read this exciting research for free until 13/08/2017 through a registered RSC account.

 

Structure/property relationships in copolymers comprising renewable isosorbide, glucarodilactone, and 2,5-bis(hydroxymethyl)furan subunits
Polym. Chem., 2017, 8, 3746-3754, DOI: 10.1039/c7py00575j

 

 

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About the webwriterAthina Anastasaki

Dr. Athina Anastasaki is a web writer for Polymer Chemistry. She is currently a Global Marie Curie Fellow working alongside Professor Craig Hawker at the University of California, Santa Barbara (UCSB). Please visit this website for more

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European Polymer Federation – Australian European Workshop

At this year’s European Polymer Federation Congress, Polymer Chemistry is pleased to sponsor the Australian-European Polymer Symposium, which will take place on Tuesday 4 July. The workshop will include 12 lectures (six from Australia, six from Europe) to illustrate connections, interactions and collaborations between European and Australian polymer researchers and will also include the presentation of Polymer Chemistry and Soft Matter poster prizes.

Invited speakers include:

Emmanuel P. Giannelis (Cornell University, USA)
Gaetano Guerra
(Università degli Studi di Salerno, Italy)
Dave Haddleton
(University of Warwick)
Tanja Junkers
(Universiteit Hasselt, Belgium)
Simon Harrisson
(Université de Toulouse III Paul Sabatier, France)
Felix Schacher
(Friedrich Schiller University Jena, Germany)
Hans Heuts
(Technische Universiteit Eindhoven, Netherlands)
Leonie Barner
(Queensland University of Technology, Australia)
Holger Schönherr 
(Universität Siegen, Germany)
Neil Cameron
(Monash University, Australia)
Markus Muellner
(University of Sydney, Australia)
Greg Qiao
(University of Melbourne, Australia)

EPF 2017 will be held from 2-7 July at the Lyon Convention Center and will focus on the latest trends in the polymer science and technology industry, including macromolecular chemistry; physics of polymers and polymer materials; modelling and simulation and polymer characterisation.

To register now, click here or visit the EPF website for more details on the speaker list and other workshops.

 

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Paper of the month: Block copolymer synthesis in one shot: concurrent metal-free ATRP and ROP processes under sunlight

Block copolymers are of a great interest to the polymer chemistry community as they provide intermediate physicochemical properties when compared to the respective homopolymers. Sequential monomer addition, mechanistic transformation and coupling of different segments are three of the most popular approaches to obtain block copolymers. However, all these approaches suffer from several drawbacks such as being limited to monomers that can be polymerized only under the same polymerization mechanism or requiring extreme experimental precautions and elongated purification steps.



In order to address the latter challenge, Yagci, Yilmaz and co-workers developed the first metal free example of block copolymer formation in which they concurrently polymerize structurally different monomers from a junction point serving as two functional groups for each polymerization. Since atom transfer radical polymerization (ATRP) and ring opening polymerization (ROP) are not expected to interfere with each other and as such could be the ideal candidates for such a system. In order to test this hypothesis, a specifically designed initiator was synthesized possessing a tertiary bromine at one end (capable of initiating an ATRP reaction) and a hydroxyl functionality at the other end (capable for initiating a ROP reaction). Under carefully optimized conditions and in the presence of both the ATRP and ROP catalysts both methyl methacrylate (MMA) and ε- caprolactone could be simultaneously polymerized yielding a diblock copolymer with good agreement between theoretical and experimental value sand low dispersity values. Interestingly, the reaction took place on the roof of the chemistry department at Istanbul technical university utilizing natural sunlight as the light source. The applicability of this technique was further demonstrated by the simultaneous polymerization of different sets of monomers including n butyl acrylate- ε- caprolactone and methyl methacrylate-lactide combinations. As such, the successful combination of ATRP with ROP in the same reaction media allows for the facile one pot synthesis of block copolymers which can find use in further applications where excess of metals or inorganic residues would be undesirable.

Tips/comments directly from the authors:

1. All chemicals should be added into the reaction tube under nitrogen atmosphere in dark (perhaps by covering the outside of the tube with an aluminium foil) to avoid any premature light induced polymerization.
2. ROP polymerization can take place even in dark. Therefore, the ROP catalyst should be added last, and afterwards, the reaction tube should be exposed to sunlight as soon as possible. This way, one can provide the optimum conditions for the polymerizations to be realized simultaneously.
3. The method is best applicable in sunny days. Sunlight was deliberately selected as the most natural and simple way of light exposure. However, various other irradiation sources that emit in the wavelength regions matching with the absorption of appropriate sensitizers can also be used.

Read this exciting research for free until 17/07/2017 through a registered RSC account.

 

Block copolymer synthesis in one shot: concurrent metal-free ATRP and ROP processes under sunlight
Polym. Chem., 2017, 8, 2899-2903, DOI: 10.1039/c7py00069c

 

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About the webwriterAthina Anastasaki

Dr. Athina Anastasaki is a web writer for Polymer Chemistry. She is currently a Global Marie Curie Fellow working alongside Professor Craig Hawker at the University of California, Santa Barbara (UCSB). Please visit this website for more

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Focus on: Naturally Occurring Polymers

This month we focus on 3 articles published in Polymer Chemistry which report the use of naturally occurring polymers. As opposed to synthetic polymers, naturally occurring polymers are produced by living organisms in nature. Classes of naturally occurring polymers include proteins, polynucleotides, polyisoprenes, lignin and polysaccharides. These polymers can be extracted and utilised in various applications. In particular, polysaccharides such as cellulose and chitosan are cheap and abundant, biodegradable and are being used increasingly due to growing environmental concerns. Here, chitosan and/or celluose are utilised for the preparation of hydrogels, cellulose modification, and with thermo-conductive carbon nanotubes, exemplifying the broad versatility of these naturally occurring polymers.

1. Highly cost-effective and high-strength hydrogels as dye adsorbents from natural polymers: chitosan and cellulose
Hu Tu, Yi Yu, Jiajia Chen, Xiaowen Shi, Jialin Zhou, Hongbing Deng, Yumin Du
Polym. Chem., 2017, 8, 2913-2921; DOI: 10.1039/C7PY00223H

The authors decribe the preparation of composite hydrogels comprising chitosan, cellulose and rectorite for use as adsorbents for waste water treatment. The hydrogels had good elasticity and strength with the ability to restore their shape after compression. The adsorption efficiency was demonstrated with a dye molecule, which was adsorbed from solution. In addition these materials show promise as adsorbents for heavy metals.

2. Tandem modification of amphiphilic cellulose ethers for amorphous solid dispersion via olefin cross-metathesis and thiol-Michael addition
Yifan Dong, Laura I. Mosquera-Giraldo, Lynne S. Taylor, Kevin J. Edgar
Polym. Chem., 2017, 8, 3129-3139; DOI: 10.1039/C7PY00228A

The combination of olefin cross-metathesis and thiol-Michael addition chemistries have been used to functionalise cellulose derivatives. This methodology allowed for the design of certain cellulose-based polymers for potential use in amorphous solid dispersion, which can enhance the bioavailability of a poorly soluble drug. Mild reaction conditions and functional group tolerance make this strategy appealing for use with other polysaccharides.

3. Thermo conductive carbon nanotube-framed membranes for skin heat signal-responsive transdermal drug delivery
Ji-Hye Kang, Han-Sem Kim, Ueon Sang Shin
Polym. Chem., 2017, 8, 3154-3163; DOI: 10.1039/C7PY00570A

Smart carbon nanotube (CNT)-framed membranes were prepared from CNTs, chitosan and a thermoresponsive polymer, with an LCST around body temperature. The chitosan was used as a biocompatible adhesive to give cohesion to the CNTs. The loading and release of bovine serum albumin (BSA) was investigated and a high loading capacity was found, with temperature-dependent release of the BSA. The hybrid memberanes show potential as patch type transdermal drug delivery devices.

Read these articles for free until July 17th


About the webwriterFiona Hatton

Dr. Fiona Hatton is a web writer for Polymer Chemistry. She is currently a postdoctoral researcher in the Armes group at the University of Sheffield, UK. Find her on Twitter: @fi_hat

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