نتایج جستجو برای: sensitive polymers
تعداد نتایج: 350527 فیلتر نتایج به سال:
Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached...
Drug delivery directly to the colon is a very useful approach for treating localised colonic diseases such as inflammatory bowel disease, ulcerative colitis, and Crohn's disease. The use of disulphide cross-linked polymers in colon targeted drug delivery systems has received much attention because these polymers are redox sensitive, and the disulphide bonds are only cleaved by the low redox pot...
We demonstrated here a facile and efficient synthesis of polyhedral oligomeric silsesquioxane-based amphiphilic polymer by thiol-ene click chemistry. The properties of polyhedral oligomeric silsesquioxane (POSS)–PEG amphiphilic polymers were studied in detail by a combination of 1H NMR, 13C NMR, 29Si NMR FT-IR, GPC, and TG analysis. The newly-designed thiol-ene protocol obtains only anti-Markov...
Smart shape-memory polymers can memorize and recover their permanent shape in response to an external stimulus (for example, heat). They have been extensively exploited for a wide spectrum of applications ranging from biomedical devices to aerospace morphing structures. However, most of the existing shape-memory polymers are thermoresponsive and their performance is hindered by heat-demanding p...
polypyrrole (ppy) nanofibers have been fabricated on glassy carbon electrode (gce) usingelectrochemical technique. electropolymerization of pyrrole (py) for the fabrication of ppy nanofiberswas occurred on gce by applying a fixed potential of about 0.85 v for 120 sec in a mild basic solutioncontaining sodium carbonate and sodium perchlorate. in the mild basic media, the monomer, py, isoxidized ...
Stimuli−responsive polymers respond with large property changes to small physical or chemical stimuli. These functional polymers are known as “smart”, “intelligent”, “stimuli−responsive”, or “environmentally sensitive” polymers. They can take many forms: they may be dissolved in aqueous solution, adsorbed or grafted on aqueous−solid interfaces, or cross−linked in the form of hydrogels. Many dif...
Responsive systems sensitive to near-infrared (NIR) light are promising for triggered release due to efficient deep tissue penetration of NIR irradiation relative to higher energy sources (e.g., UV), allowing for spatiotemporal control over triggering events with minimal potential for tissue damage. Herein, we report star polymers containing thermally-labile azo linkages that dissociate during ...
pH sensitive dodecyl-modifi ed poly(allylamine)s associate with superoxide dismutase (SOD) in aqueous solutions at pH 5.5 and 7.4. The bound SOD can be released completely at pH 10.0 due to the self-aggregation of the polymers. In a mixture of water and organic solvent, the hydrophobic groups of the polymers are exposed. During the process of removing the organic solvent, the polymers increase ...
This paper reports the results of an investigation of the effects of purity level and nature of impurities on the properties of recycled polycarbonate and recycled acrylonitrile-butadiene-styrene polymers blended with the corresponding virgin resins. The relevant thermal, mechanical and flow properties were measured. It is concluded that properties of recycled polymers depend not only on the am...
Polymers for hot melt extrusion must exhibit thermoplastic characteristics in order to permit the melt extrusion process and they must be stable at extrusion temperatures. Other relevant characteristics are: suitable glass transition temperature (Tg) of 50–180 °C, low hygroscopicity and no toxicity since larger amounts of polymer are used [1]. Extrudability of a polymer is mainly determined by ...
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