Lehmanhirsch3119

The limited reactivity of starch towards maleic anhydride (MA) affords maleate with a low degree of MA substitutions (CC and COOH groups). In this study, we investigated the relationship between the starch structure, controlled by its amylose (AM)/amylopectin (AP) ratio, and the DS of starch maleates using C4[mim]Cl as the recyclable media, and catalyst. The results indicated that starches with varying AM/AP ratio produced maleates with comparable CC groups (DSNMR = 0.06-0.07). Following dissolution, the high amylose (DStitration = 1.17, yield = 69.2 %) and regular starches (DStitration = 1.17; yield = 59.3 %) produced high DStitration maleates (COOH groups) at MA/AGU ratio of 121 (80 °C, 10 min). Comparatively, DStitration value of waxy starch maleates (DStitration = 0.88, yield = 59.3 %) was lower than AM-based starches, possibly due to the crosslinking tendency of AP branches consisting of carboxylic end-groups. Interestingly, DStitration value for EHCS (1.17) ranged between its bulk (DSNMR 0.06) and surface distribution of MA (DSSXPS 1.7); therefore, we considered it reliable for future reference. An efficient and bio-based alginate pillared hydrotalcite (SA@LDHs) was fabricated via calcination-reconstruction manner with sodium alginate (SA) and hydrotalcite (LDHs-C), and used as novel flame retardant for polypropylene (PP). The morphologies and combustion properties of SA@LDHs and its hybrid with PP composites (PP/SA@LDHs) had been characterized by SEM, TGA, cone calorimetry, LOI and UL-94 measurements. With 30 wt% loading, the SA@LDHs achieved a LOI value of 30.9 % and a UL-94 V-0 rating, whereas the LDHs-C exhibited only LOI value of 27.6 % and a UL-94 V-1 rating. The peak heat release rate, total heat release and total smoke production of PP/SA@LDHs were 260.8 kW m-2, 61.3 MJ m-2 and 8.2 m2, respectively, which presented declines of 69.2 %, 42.8 % and 32.2 % compared with those of Neat PP. These improvements could be attributed to the presence of the radical-trapping effect of SA, which leading to promote PP chains to participate in the carbonization process. A novel adsorbent material composed of chitosan (Cs), polyvinyl alcohol (PVA) and polyethylene glycol (PEG) was prepared in hydrogel bead form to efficiently remove copper ions from aqueous solutions. The properties of the composite were characterized by scanning electronic microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR). The adsorption behavior of Cu(II) onto Cs/PVA/PEG beads was studied as a function of solution pH, temperature and contact time. The maximum adsorption was observed equal to 99.99 % for initial copper ion concentration of 25 mg/L at pH 5, temperature 45 °C, 5 h as contact time and 1 g/L of adsorbent dose. Langmuir isotherm and pseudo-second kinetic model fitted the experimental data sufficiently. Thermodynamic studies indicated that the process was spontaneous and endothermic. Cs/PVA/PEG beads can act as an effective adsorbent for the removal of Cu(II) from aqueous solution.We report a facile method to prepare a novel composite based on Fe-Cu alloy decorated cellulose nanocrystals (Fe-Cu@CNC) via simple oxidation-reduction reaction. Spherical zero-valent iron nanoparticles (NZVI) and sheet-like copper nanoparticles were serially anchored on the CNC surface, and the generated composite exhibited excellent antibacterial activities and highly efficient Pb2+ removal. The composites had high antibacterial ratios of 95.9 %-99.9 %, because superoxide radicals can cause irreversible damage to the bacteria, eventually leading to apoptosis and bacterial death. Meanwhile, the Fe-Cu@CNC composite showed quick Pb2+ ion removal, reaching a 70.76 % removal within 5 min, a total removal of 93.98 % after 1 h, and excellent reusability (retaining removal efficiency of 80.41 % after six cycles). The adsorption kinetics demonstrated that the adsorption behavior can be described by pseudo-second-order kinetic model (R2>0.99). This study offers a new strategy to prepare a promising composite with advanced antibacterial and heavy metal removal properties for wastewater treatment. In recent years, extensive efforts have been devoted to electronic miniaturization and integration. Accordingly, heating up of electronics has become a critical problem that needs to be urgently solved by efficient and reliable thermal management. Electronic device substrates made of cellulose nanofibrils (CNFs) exhibit outstanding flexibility, mechanical properties, and optical properties. Combining CNFs with high-thermal-conductivly fillers is an effective thermal management technique. This paper focuses on the thermal management of electronic devices and highlights the potential of CNF-based materials for efficient thermal management of energy storage electronic such as supercapacitors, lithium-ion batteries and solar cells. A high-thermal-conductivity composite material for electronic devices can be obtained by combining CNFs as the framework material with carbon nanotubes, graphene, and inorganic nitrides. Moreover, The research progress in the application of CNFs-based materials for supercapacitors, lithium-ion batteries and solar cells is highlighted, and the emerging challenges of different CNFs-based energy storage devices are discussed. We study the dilute solution properties and entangled dynamics of hydroxypropyl cellulose (HPC), a semiflexible polymer, in aqueous solution. Intrinsic viscosity data are consistent with a polymer in θ solvent with a Kuhn length ≃22 nm. The overlap concentration, estimated as the reciprocal of the intrinsic viscosity scales with the degree of polymerisation as c* ∝ N-0.9. We evaluate different methods for estimating the entanglement cross-over, following the de Gennes scaling and hydrodynamic scaling models, and show that these lead to similar results. Above the entanglement concentration, the specific viscosity, longest relaxation time and plateau modulus scale as ηsp ≃ N3.9c4.2, τ ≃ N3.9c2.4 and GP ≃ N0c1.9. A comparison with other polymers suggests that the rheological properties displayed by HPC are common to many polysaccharide systems of varying backbone composition, stiffness and solvent quality, as long as the effect of hyper-entanglements can be neglected. OUL232 supplier On the other hand, the observed scaling laws differ appreciably from those of synthetic flexible polymers in good or θ-solvent.