Normanliu5018

Tryptophan (Trp) decorated hydroxypropyl methylcellulose (HPMC) cryogels were prepared by a one-step reaction with citric acid. The increase of Trp content in the 3D network from 0 to 2.18 wt% increased the apparent density from 0.0267 g.cm-3 to 0.0381 g.cm-3 and the compression modulus from 94 kPa to 201 kPa, due to hydrophobic interactions between Trp molecules. The increase of Trp content in HPMC-Trp hydrogels increased the amount of non-freezing water, estimated from differential scanning calorimetry, and the amount of freezing water, which was determined by time-domain nuclear magnetic resonance. The adsorption capacity of methylene blue (MB) and rhodamine B (RB) on HPMC-Trp hydrogels increased with Trp content and the amount of freezing water. HPMC-Trp hydrogels could be recycled 6 times keeping the original adsorptive capacity. The diffusional constants of MB and RB tended to increase with Trp content. RB adsorbed on HPMC-Trp hydrogels presented a bathochromic shift of fluorescence.Poly(N-isopropyl acrylamide) grafted heparin and chondroitin sulfate were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. The copolymers were characterized by NMR, IR, SEC, DLS, SLS and NTA methods. High grafting densities were reached for both glycosaminoglycans. The temperature, pH and polymer concentration affected the low critical solution temperatures values. The increased pNIPAAm chain length, grafting density and concentration led to the sharp phase transition at 35 °C. Spherical nanogels were formed around this temperature. Terminal dodecyl trithiocarbonate groups of the copolymers were reduced to thiols that allowed formation of sensitive nanogels with sharp phase transitions induced by pNIPAAm chains. The copolymers showed no toxicity to the ocular cells and they provided the prolonged release of dexamethasone phosphate at 37 °C. These copolymers are interesting alternatives for ocular drug delivery.The main intent of this investigation was to retain the strength and superabsorbency of natural and non-toxic biodegradable polymers using an innovative combination of cross-linkers for application as the absorbent core of sanitary napkins. For this, sodium carboxymethyl cellulose (NaCMC) and starch were blend to form membranes by phase inversion and lyophilisation, using an optimized cross-linker combination of sodium trimetaphosphate (STMP) and aluminium sulphate (AlS). Optimal cross-linking of NaCMC and starch hampered membrane dissolution and disintegration, yielding a microtextured surface morphology. The membranes were biodegradable and yet possessed the requisite flexibility and mechanical strength for the proposed application, without compromise of superabsorbency. Lyophilised membranes possessed higher immediate water and blood sorption with ∼50% water retention capabilities when compared to the phase inversion technology. The results suggest that the developed membranes can be a cost-effective degradable alternative to the commercial polyacrylate-based nonbiodegradable sanitary products.Catechol-conjugated chitosan (CCs), used as tissue adhesive, wound dressing, and hemostatic materials, has been drawing much more attention. However, most CCs tissue adhesives exhibit poor adhesion strength, and few studies on optimization of cohesion and adhesion strength of CCs derivatives have been conducted. This work focused on the balance between cohesion and adhesion strength of catechol-conjugated chitosan (CCs) derivatives via different mechanisms of chemical and enzymatic conjugation. CCs derivatives were characterized regarding its mechanical property, cytotoxicity, platelet adhesion and wound healing test. Mechanical properties could be optimized by the degree of catechol substitution, pH and the presence of oxidizing agent, resulting in that the highest value of adhesive shear strength to the porcine tissue is 64.8 ± 5.7 kPa. In addition, CCs derivatives exhibit decreased toxicity and promoted in vivo wound healing effects as comparing to a commercially available adhesive (Dermabond®). All the results demonstrate that CCs derivatives can be used as well-optimized tissue adhesives as well as a hemostat.The development of lightweight, strong and high-performance thermal insulators from renewable biomass are highly desired for sustainable development. Here, ultralight aerogels based on renewable nanochitin with outstanding mechanical properties, excellent water-resistant, and promising thermal insulation properties are fabricated. The pristine nanochitin aerogels (PNCAs) assembled from mechanically strong carboxylated chitin nanorods are firstly prepared through acid-induced gelation and supercritical drying. The resultant PNCAs present tunable density (10-50 mg/cm3) and strong mechanical stiffness (the specific compression modulus of 30.2 MPa cm3/g) combining with low thermal conductivity (27.2 mW/m K). After a facile silylation modification, the silylated nanochitin aerogels (SNCAs) exhibit hydrophobic behavior (contact angle >130°), improved compression performance (the specific compression modulus of 65 MPa cm3/g), and promising thermal insulation property (30.5-35.8 mW/m K). Moreover, the silylated aerogel shows a negligible loss of mechanical performance when exposed to water for 12 h at 35 °C.As an indispensable component, separator is close related to electrochemical performance and safety of lithium-ion batteries (LIBs). click here However, the current widely applied polyolefin microporous separator impedes the development of high power LIBs due to poorer electrolyte wettability and inferior thermal stability. Herein, heat-resistant polyphenylene sulfide (PPS) fibers and cellulose fibers (CFs) are adopted to fabricate a novel composite separator (CFs/PPS) via a facile papermaking process. The as-prepared CFs/PPS separator exhibits higher porosity, improved electrolyte uptake and superior wettability. These boost its ionic conductivity and decrease interfacial resistance between CFs/PPS separator and electrode, which further endow battery with good rate capability. Moreover, in comparison to commercial polypropylene separator, CFs/PPS separator gives superior thermal stability, satisfactory mechanical strength, broader electrochemical window and more stable cycle performance. Accordingly, CFs/PPS composite separator is very promising for application in high power LIBs.