Macromolecular Bioscience

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August 26, 2014

POLYOLEFINS: Thermal Behavior of Polyethylene Reactor Alloys Polymerized by Ziegler-Natta/Late Transition Metal Hybrid Catalyst

POLYOLEFINS: Thermal Behavior of Polyethylene Reactor Alloys Polymerized by Ziegler-Natta/Late Transition Metal Hybrid Catalyst

Saeid Ahmadjo, Samaneh Dehghani, Gholam Hossein Zohuri, Gholam Reza Nejabat, Hamed Jafarian, Mostafa Ahmadi and Seyed Mohammad Mahdi Mortazavi*

Ziegler-Natta (ZN) and late transition metal (LTM) hybrid catalysts were synthesized and utilized in preparation of polyethylene (PE) reactor alloys. By changing reaction parameters, versatile thermal behavior from LTM-PE to ZN-PE could be obtained. The proposed method seems to be a promising approach for synthesis of tailor-made polyethylene in a single reactor.

Macromol. React. Eng. DOI: 10.1002/mren.201400024

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

August 07, 2014

POLYOLEFINS: Preparation of Nanocomposites of Polypropylene with Carbon Nanotubes via Masterbatches Produced by In Situ Polymerization and by Melt Extrusion

POLYOLEFINS: Preparation of Nanocomposites of Polypropylene with Carbon Nanotubes via Masterbatches Produced by In Situ Polymerization and by Melt Extrusion

Rafael S. Araujo, Renato J. B. Oliveira and Maria de Fátima V. Marques*

A new PP/multi-walled carbon nanotube (MWCNT) masterbatch is synthesized via in situ polymerization and compared with a masterbatch obtained by melt mixing. Both masterbatches are used for the realization of PP/MWCNT nanocomposites by mixing with a commercial PP in a extruder. It is shown that the use of the masterbatch synthesized in situ provides additional enhanced thermal stability and mechanical properties.

Macromol. React. Eng. DOI: 10.1002/mren.201400012

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

July 03, 2014

POLYOLEFINS: Catalytic Olefin Polymerization Process Modeling: Multi-Scale Approach and Modeling Guidelines for Micro-Scale/Kinetic Modeling

POLYOLEFINS: Catalytic Olefin Polymerization Process Modeling: Multi-Scale Approach and Modeling Guidelines for Micro-Scale/Kinetic Modeling

Vasileios Touloupidis

This work presents the basic framework for catalytic olefin polymerization kinetic modeling. It provides an insight for a better understanding of the kinetic models, offering the starter-kit tools for developing similar approaches in the complex but extremely interesting area of polymerization kinetic reaction engineering.

Macromol. React. Eng. DOI: 10.1002/mren.201300188

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

July 03, 2014

Functional Polymers: Synthesis and Photovoltaic Properties of New Multifused Anthradithiophene-Based Narrow-Bandgap D-A Copolymers

Functional Polymers: Synthesis and Photovoltaic Properties of New Multifused Anthradithiophene-Based Narrow-Bandgap D-A Copolymers

Qi-Da Liu, Rui-Xiang Peng, Shao-Jie Chen, Ling Ai, She-Yu Wang, Zhi-Yang Liu and Zi-Yi Ge*

Three structurally novel anthradi­thiophene-based donor-acceptor (D-A) copolymers are synthesized and used to fabricate polymer solar cells. Under identical post-processing conditions, the power conversion efficiency (PCE) of inverted polymer solar cell (PSC) devices is over two times higher than in corresponding conventional devices. The improved efficiencies for inverted devices are due to the close energy alignment between the work function of the MoO3 and the highest occupied molecular orbital (HOMO) energy levels of the copolymers.

Macromol. Chem. Phys., DOI: 10.1002/macp.201400119

Other contributions to the special series on functional polymers can be found here.

June 23, 2014

POLYOLEFINS: Kinetics and Growth of Polyethylene Nanofibrils over Metallocene Catalyst Supported on Flat Silica and Spherical

POLYOLEFINS: Kinetics and Growth of Polyethylene Nanofibrils over Metallocene Catalyst Supported on Flat Silica and Spherical

Sang Yool Lee and Kyu Yong Choi*

A catalyst loaded flat silica surface is deposited with methylaluminoxane (MAO) and a rac-Et(indenyl)2ZrCl2 catalyst. The polymer grows as nanofibrils of about 30-45 nm diameter. Some MAO clusters are formed and catalytic sites are concentrated in these clusters. The flat silica supported catalyst exhibit highest catalytic activity.

Macromol. React. Eng. DOI: 10.1002/mren.201400018

Other contributions to the article series on "Polyolefins - Catalyst and Process Innovations" can be found here.

June 18, 2014

NEW TECHNOLOGIES: Bulk Crosslinking Copolymerization: Comparison of Different Modeling Approaches

NEW TECHNOLOGIES: Bulk Crosslinking Copolymerization: Comparison of Different Modeling Approaches

Stefano Lazzari, Shaghayegh Hamzehlou, Yuri Reyes, Jose Ramon Leiza, Mário Rui P. F. N. Costa, Rolando C. S. Dias and Giuseppe Storti*

The present paper compares the predictions of different modeling approaches on a bulk crosslinking copolymerization scheme. Models based on average properties match the predictions of more detailed models in terms of average predictions, but not for chain length distributions. As a result, guidelines for the most-suitable usage of such models are provided.

Macromol. React. Eng. DOI: 10.1002/mren.201400005

Other contributions to the article series on new technologies in polymer reaction engineering can be found here.

June 03, 2014

Functional Polymers: Optical and Electroluminescent Studies of White-Light-Emitting Copolymers Based on Poly(9,9-dioctylfluorene) and Fluorenone Derivatives

Functional Polymers: Optical and Electroluminescent Studies of White-Light-Emitting Copolymers Based on Poly(9,9-dioctylfluorene) and Fluorenone Derivatives

Hua Wang,* Junli Yang, Jing Sun, Yang Xu, Yuling Wu, Qingcheng Dong, Wai-Yeung Wong,* Yuying Hao, Xinwen Zhang and Hua Li

A class of white-light-emitting copolymers based on polyfluorene is synthesized, in which 2,7-di-(2-thienyl)-9-fluorenone (DTFO) is introduced as the orange-emitting unit. It can be used in white-light organic light-emitting diodes with a single light-emitting layer. The color of the white light can be tuned by changing the content of DTFO.

Macromol. Chem. Phys., DOI: 10.1002/macp.201400070

Other contributions to the special series on functional polymers can be found here.

May 26, 2014

TREND: Polymers for Luminescent Sensing Applications

TREND: Polymers for Luminescent Sensing Applications

Hyungwoo Kim, Youngdo Kim andJi Young Chang*

Polymers are widely used for chemical sensing applications, as a receptor or as a signal transducer. Fluorescent conjugated polymers are extensively studied for sig­naling. Molecularly imprinted polymers are artificial receptors fabricated using the molecular-imprinting technique. In this article, the recent developments on luminescent polymeric sensors are briefly summarized.

Macromol. Chem. Phys., DOI: 10.1002/macp.201400128

More information on the invited Talent, Trend, and Highlight articles in Macromolecular Chemistry and Physics can be found here.

July 30, 2013

Stem Cells: Advanced Polymers for Stem Cell Research - From Laboratory to Clinic

Stem Cells: Advanced Polymers for Stem Cell Research - From Laboratory to Clinic

Suwan N. Jayasinghe

Guest-editor Suwan N. Jayasinghe introduces the third and last part of the series: Advanced Polymers for Stem Cell Biology and Medicine. In this final part it is further demonstrated how the exploration of biopolymers can lead to a wide range of applications from stem cell culturing to their exploration as vehicles for cells and/or genes. Again, this series demonstrates how progress in this highly interesting field can only be reached by the bridging of several disciplines of research and development.

Macromol. Biosci., DOI: 10.1002/mabi.201300064

July 29, 2013

Stem Cells: In Vitro Neo-Cartilage Formation

Stem Cells: In Vitro Neo-Cartilage Formation

Sumrita Bhat, Lars Lidgren and Ashok Kumar*

Limited blood supply and the avascular nature of articular cartilage restrict its self-repair capacity, frequently leading to osteoarthritis. Researchers from India and Sweden focus on scaffolds for tissue repair from natural polymers, for example gelatin, chitosan, and agarose in the form of composites. A novel way of fabrication, known as cryogelation, is presented, in which matrices are synthesized at sub-zero temperature. Cell seeded scaffolds incubated under appropriate conditions result in the accumulation of matrix components on the surface of the gel in the form of neo-cartilage. Neo-cartilage exhibits similarity to native cartilage with respect to its physical, mechanical and biochemical properties. Based on these similarities it can provide a new approach for the treatment of localized joint injuries.

Macromol. Biosci., DOI: 10.1002/mabi.201200484

July 28, 2013

Stem Cells: The Fate of Tissue Development

Stem Cells: The Fate of Tissue Development

Anuj Tripathi, Tanushree Vishnoi, Deepti Singh, and Ashok Kumar*

Cell to matrix interactions affect in vitro cell adherence and proliferation and further decide the fate of tissue development for biomedical applications. This study demonstrates the role of crosslinking in altering the surface properties of 3D porous cryogel matrices. Glutaraldehyde and 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide crosslinkers are used separately for the crosslinking of alginate and gelatin, respectively. The difference in crosslinking affects the physiochemical properties of these matrices leading to variable cell behavior as demonstrated using four different cell types. The present study demonstrates the successful use of controlled crosslinking in directing the cell growth for tissue engineering.

Macromol. Biosci., DOI: 10.1002/mabi.201200398

July 27, 2013

Stem Cells: Phenotype-Independent Effects of Retroviral Transduction in Human Dental Pulp Stem Cells

Stem Cells: Phenotype-Independent Effects of Retroviral Transduction in Human Dental Pulp Stem Cells

Obi Egbuniwe,* Andrew D. Grant, Tara Renton, and Lucy Di Silvio*

There has been considerable progress in the development of biopolymers that could impact directly on in vivo stem cell fate. Present-day biopolymers are being designed to mirror the well-described relationship existing between stem cells and the extracellular matrix. Researchers from London highlight the importance of the maintenance of cell viability and the development of human tissue-sourced stem cell lines. A better understanding of in vitro responses of these specialized cells to changes in their tightly regulated microenvironments will allow the utilization of their full therapeutic potential in biomimetic constructs

Macromol. Biosci., DOI: 10.1002/mabi.201300020

August 26, 2014
POLYOLEFINS: Thermal Behavior of Polyethylene Reactor Alloys Polymerized by Ziegler-Natta/Late Transition Metal Hybrid Catalyst

August 07, 2014
POLYOLEFINS: Preparation of Nanocomposites of Polypropylene with Carbon Nanotubes via Masterbatches Produced by In Situ Polymerization and by Melt Extrusion

July 03, 2014
POLYOLEFINS: Catalytic Olefin Polymerization Process Modeling: Multi-Scale Approach and Modeling Guidelines for Micro-Scale/Kinetic Modeling

July 03, 2014
Functional Polymers: Synthesis and Photovoltaic Properties of New Multifused Anthradithiophene-Based Narrow-Bandgap D-A Copolymers

June 23, 2014
POLYOLEFINS: Kinetics and Growth of Polyethylene Nanofibrils over Metallocene Catalyst Supported on Flat Silica and Spherical

June 18, 2014
NEW TECHNOLOGIES: Bulk Crosslinking Copolymerization: Comparison of Different Modeling Approaches

June 03, 2014
Functional Polymers: Optical and Electroluminescent Studies of White-Light-Emitting Copolymers Based on Poly(9,9-dioctylfluorene) and Fluorenone Derivatives

May 26, 2014
TREND: Polymers for Luminescent Sensing Applications

July 30, 2013
Stem Cells: Advanced Polymers for Stem Cell Research - From Laboratory to Clinic

July 29, 2013
Stem Cells: In Vitro Neo-Cartilage Formation

July 28, 2013
Stem Cells: The Fate of Tissue Development

July 27, 2013
Stem Cells: Phenotype-Independent Effects of Retroviral Transduction in Human Dental Pulp Stem Cells

August 15, 2012
Stem Cells: Maintaining Stem Cells with Hydrogels

August 15, 2012
Stem Cells: Hydrogel/Mineral Composites for Bone Tissue Repair

August 15, 2012
Stem Cells: Artificial Organs

August 07, 2012
Stem Cells: Hydrogels from Natural Polysaccharides as 3D Cell Delivery System

August 07, 2012
Stem Cells: Electrospun PLA Fibers for Controlled TCP Release

August 02, 2012
Stem Cells: Fiber Thickness to Direct Stem Cell Differentiation

August 02, 2012
Stem Cells: PLLA/MWCNT Composites as Conductive Biomaterials

June 01, 2012
Stem Cells: Understanding Embryo Formation

May 31, 2012
Stem Cells: Multifunctionalized Nanoparticle Systems for Treatment of Central Nervous System Diseases

March 23, 2012
Stem Cells: Gelatin-Based Hydrogels as Potential Implantable Carriers for Stem Cells

March 22, 2012
Stem Cells: Polymeric Systems for Tissue Engineering and Biomedical Applications

January 31, 2012
Stem Cells: Polymer-based Scaffold Designs For In Situ Vascular Tissue Engineering: Controlling Recruitment and Differentiation Behavior of Endothelial Colony Forming Cells

December 20, 2011
Stem Cells: Mechanical Properties and Topographical Features in Concert - Influence on Cell Migration

December 19, 2011
Stem Cells: A Dextran-Based Polymer as Cell-Detaching Substrate

October 24, 2011
Stem Cells: Tissue-Specific Stem Cell Differentiation in an in vitro Airway Model

October 23, 2011
Stem Cells: Pullulan Hydrogels for Skin Regeneration

October 22, 2011
Stem Cells: Advanced Polymers for Stem Cell Research - The Series Continues

June 21, 2011
Stem Cells: A Library of Polyureas for Ligament Tissue Engineering

April 05, 2011
Stem Cells: A Tool for Studying Stem Cells during Wound-Healing Processes

April 05, 2011
Stem Cells: Polymeric Scaffold for Adipose Stem Cells in Bone Tissue Engineering

March 16, 2011
Stem Cells: ECM Functionalized Microcavities to Control Hematopoietic Stem and Progenitor Cell Fate

March 16, 2011
Stem Cells: Injectable Scaffold for Cardiac Tissue Engineering

February 17, 2011
Stem Cells: Moving Gradient Generation to the Third Dimension

February 15, 2011
Stem Cells: Low Thrombogenicity Coatings for Vascular Grafts

January 14, 2011
Stem Cells: Biodegradable Elastomers for Tissue Engineering and Cell–Biomaterial Interactions

December 16, 2010
Stem Cells: Agarose-Alginate Cryogel for Bioengineering Applications

December 16, 2010
Stem Cells: How to Sterilize PET Fibers for Vascular Grafts

November 09, 2010
Stem Cells: Advanced Polymers for Stem Cell Biology and Medicine

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