نتایج جستجو برای: copolymers

تعداد نتایج: 8591  

2008
Hyun A Kang Hindy E. Bronstein Timothy M. Swager

The synthesis and electrochemical properties of novel block copolymers are reported. Three different norbornene derivatives having phenylene-thiophene, phenylene-bithiophene, and phenylene-furan structures were copolymerized with either norbornene or 7-oxanorbornene derivatives via ring-opening metathesis polymerization (ROMP). Block copolymers’ stabilities and solubilities could be improved by...

2007

Starch graft copolymers are expected to become increasingly important as industrial and consumer chemicals in a large variety of end uses. Therefore, a quick and accurate analytical characterization of the graft copolymer is desirable. Vinyl side chains from starch-vinyl graft copolymers have preViously been isolated by several methods. Brockway (1) hydrolyzed the starch moiety with 1 N HCl at ...

2017
Maithri Tharmavaram Deepak Rawtani Gaurav Pandey

Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostructures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers wi...

Journal: :Biomacromolecules 2005
Chunyu Xu Victor Breedveld Jindrich Kopecek

A series of triblock protein copolymers composed of a central water-soluble polyelectrolyte segment flanked by two coiled-coil domains was synthesized by genetic engineering methods. The copolymers self-assembled into reversible hydrogels in response to changes in temperature, pH, and the presence or absence of denaturating agent (guanidine hydrochloride, GdnHCl). Hydrogel formation was concent...

Journal: :Biomaterials science 2013
Peter M Carlson Joan G Schellinger Joshuel A Pahang Russell N Johnson Suzie H Pun

Polyethylenimine (PEI), one of the most frequently used polycations for non-viral nucleic acid delivery, exhibits good transfection efficiency to cultured cells but generally has to be used in restricted concentration ranges due to high cytotoxicity. We recently reported a family of HPMA-co-oligolysine brush copolymers that show nucleic acid delivery efficiencies approaching that of PEI. Guanid...

2017
Milica Stanković Christine Hiemstra Hans de Waard Johan Zuidema Rob Steendam Henderik W. Frijlink Wouter L.J. Hinrichs

In this study, novel hydrophilic multiblock copolymers composed of semi-crystalline poly(ε-caprolactone) [PCL] blocks and amorphous blocks consisting of poly(D,Llactide) (PDLA) and poly(ethylene glycol) (PEG) [PDLA-PEG] were synthesized. The block ratio of these [PDLA-PEG]-b-[PCL] multiblock copolymers was varied and the degradation of implants prepared of these polymers by hot melt extrusion (...

Journal: :Macromolecular rapid communications 2016
In-Sik Kim In-Bok Kim Dong-Yu Kim Seong-Hoon Kwon Do-Kyeong Ko

The femtosecond transient absorption (TA) characterization of a new benzothiadiazole (BT)-based donor-acceptor conjugated copolymer, poly[(2,6-dithieno[3,2-b:2',3'-d]thiophene)-alt-(4,7-di(4-octyldodecylthiopen-2-yl)-2,1,3-benzo[c][1,2,5]thiadiazole (PBT), as well as its fluorinated derivatives, PFBT and PDFBT, is carried out. Additionally, bulk heterojunction (BHJ) films consisting of the copo...

2017
Iwona Kwiecień Iza Radecka Marek Kowalczuk Katarzyna Jelonek Arkadiusz Orchel Grażyna Adamus

The novel copolymers composed of poly-γ-glutamic acid (γ-PGA) and oligoesters have been developed. The structures of the obtained copolymers including variety of end groups were determined at the molecular level with the aid of electrospray ionization multistage mass spectrometry (ESI-MSn). The fragmentation experiment performed for the selected sodium adducts of the copolymers confirmed that t...

2015
Chainika Jangu Jing-Han Helen Wang Dong Wang Gregory Fahs James R. Heflin Robert B. Moore Ralph H. Colby Timothy E. Long

Reversible addition–fragmentation chain transfer (RAFT) polymerization enabled the synthesis of welldefined A–BC–A triblock copolymers containing a synergy of pendant ether and imidazolium sites. The soft central BC block comprises low Tg di(ethylene glycol) methyl ether methacrylate (DEGMEMA) and 1-(4-vinylbenzyl) methyl imidazolium units. External polystyrene blocks provide mechanical reinfor...

2005
P. SAVITHA D. N. SATHYANARAYANA

A series of poly(o-/m-toluidine-co-o-/m-chloroaniline) copolymers of different compositions were synthesized by an emulsion method with ammonium persulfate as the oxidant. The conductivity of the copolymers was two to five orders of magnitude higher than that of the homopolymers poly(o-toluidine) and poly(m-chloroaniline). Among the copolymers, the copolymer of o-toluidine and m-chloroaniline e...

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