Jamisonkorsholm6543

As the most common structure of chitin, α-chitin is insoluble in common aquatic and organic solvents, and is very difficult to be processed due to its highly ordered crystalline structure and the large number of intermolecular and intramolecular hydrogen bonds. Amorphization of α-chitin has been proved to be a valid measure for improving its subsequent functionalization efficiency and depolymerization yield. In this study, superfine grinding (SFG) was introduced to make α-chitin amorphous, and it was found that SFG effectively reduced the particle size, changed the microstructure, and significantly reduced the crystallinity of α-chitin. Chitin with crystallinity as low as 8.39 % was obtained after 60 min of SFG treatment, and the amorphous chitin became readily dissolved in 10 % NaOH solution after one round of freezing-thawing process. As continuous manner could be employed, SFG might be a powerful and efficient method for preparing amorphous chitin to help its processing and modification of various applications. This work brings together thermo-mechanical and structural information for plasticized cellulose acetate (CA) by lactates and octanoic acid. CA are processed with plasticizer due to their high Tg and their strong H-bonding network. We prepared CA / plasticizer blends by corotative twin screw extruder and by solvent casting methods. The study of the different relaxations and of the glassy zone modulus was performed by dynamic mechanical analysis (DMA). The miscibility range of cellulose acetate blends were identified by the analysis of the tan δ. Depending on the composition of the system, one or two transitions are noted, this last result indicates the presence of a phase rich in CA and another in plasticizer. To connect this information to crystallinity and molecular organization, X-ray diffraction analyses were carried out. The disappearance of crystallinity allows the plasticization of previously inaccessible zones, causing a glassy modulus drop of more than 1000 MPa. Zanubrutinib Chitosan/collagen films were developed and characterized in order to assess the suitability of these films for biomedical applications. Hence, physicochemical, thermal, barrier and mechanical properties were analyzed and related to the film structure, which showed the prevalence of the triple helix of native collagen after the addition of chitosan. Furthermore, collagen fiber diameter changed from 3.9 ± 0.6 μm, for collagen films without chitosan, to 1.8 ± 0.5 μm, for collagen films with low molecular weight chitosan. These results suggested interactions between collagen and chitosan molecules, as observed by Fourier transform infrared (FTIR) analysis. Regarding film barrier properties, chitosan/collagen films showed a water vapor transmission rate around 1174 g m-2 day-1, suitable for biomedical applications such as wound healing. Additionally, biological tests confirmed that the chitosan/collagen films developed are suitable for biomedical applications. To obtain efficient oil-water separation materials with responsiveness, cellulosic porous materials with switchable wettability in response to pH changes were developed by reacting cellulose acetoacetate sponges with alkylamines of varying carbon chain length via dynamic covalent enamine bonds. The resulting sponges reversibly changed between being superhydrophilic (θwater = 0°) and highly hydrophobic (maximal θwater = 146°) under suitable pH conditions while maintained the favorable porous structures. Notably, the functionalized sponges exhibited high and selective oil absorption capacity (40-80 g/g) and satisfying desorption ability of 80%, and could efficiently separate oil-water mixtures and emulsions with extremely high efficiency (> 99%) in a controllable manner. With the three-dimensional micro/nano porous structure, switchable wettability and intrinsic environmentally friendliness, the pH responsive cellulosic sponges developed here hold great potential in controllable oil-water separation and oily wastewater purification. Chitosan has attracted much attention in drug delivery, however, carboxymethyl chitosan (CMC)-based self-aggregated nanocarriers are seldom reported. In this paper, two kinds of CMC-based pH-responsive amphiphilic chitosan derivatives, N-2-hydroxylpropyl-3-butyl ether-O-carboxymethyl chitosan (HBCC) and N-2-hydroxylpropyl-3-(2-ethylhexyl glycidyl ether)-O-carboxymethyl chitosan (H2ECC), have been synthesized by the homogeneous reaction. The molecular structures were characterized by FTIR, 1H NMR and 13C NMR. The optimum reaction condition was obtained based on the data of 1H NMR spectrum reaction time of 4 h, reaction temperature of 80 °C and nepoxyn-NH2 of 3/1, respectively. The XRD patterns showed the crystallinity of HBCC and H2ECC decreased due to the introduction of hydrophobic segments. The thermostability of HBCC and H2ECC was improved for the formation of heat-resistant stereo-complexed structures. The intermolecular hydrophobic interaction hindered the intermolecular mobility by increasing glass transition temperature of ca. 10 °C. Both HBCC and H2ECC have very low critical aggregation concentrations (HBCC 0.66-1.56 g/L, H2ECC 0.57-1.07 g/L) and moderate aggregate particle size, which is advantageous for utilization as a drug carrier. The curcumin loaded HBCC and H2ECC aggregates showed nontoxicity, meanwhile, HBCC and H2ECC showed good antibacterial activity against Staphylococcus aureus and Escherichia coli. As a result of these two favorable properties, HBCC and H2ECC could be used as curcumin nanocarriers as well as antibacterial agents. To extend the applications of natural products in nanomedicine, novel cellulose-based supramolecular nanoparticles (SNPs) were fabricated via a host-guest driven self-assembly strategy here. The adamantane-grafted carboxyethyl hydroxyethyl cellulose and β-cyclodextrin-grafted glycerol ethoxylate were synthesized to self-assemble into the SNPs. Furthermore, doxorubicin (DOX)-functionalized β-cyclodextrin was encapsulated into SNPs via an in situ co-assembly process to generate DOX-loaded SNPs (DOX-SNPs). The SNPs exhibited a quasi-spherical morphology with an average diameter of ∼25 nm. The DOX-SNPs with relatively larger diameter possessed a high DOX loading efficiency (∼94 %) and the pH-responsive drug release behaviors, which made them suitable as a drug delivery system. In vitro cytotoxicity assays demonstrated the excellent cytocompatibility of SNPs and the efficient inhibition of Hela cell proliferation of DOX-SNPs. Moreover, the DOX-SNPs could effectively enter Hela cells via endocytosis and release DOX under endo/lysosome pH.