نتایج جستجو برای: copolymers
تعداد نتایج: 8591 فیلتر نتایج به سال:
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...
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 ...
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...
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...
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...
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 (...
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...
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...
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...
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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