摘要：
Biodegradable ethyl cellulose (EC) based microcapsules for controlled delivery of Argy Wormwood solution (AWS) was prepared in this study by emulsion-solvent evaporation method using ethyl acetate as solvent. Effects of emulsifier, AWS concentration, EC concentration and ratios of core to shell on the size of the microcapsules, encapsulation efficiency (EE) and drug content were also examined in this study. The increase in the AWS or EC concentrations resulted in enlargement of the microcapsules'. The drug loading increased from 23% to 48% as the AWP concentration was changed from 2 wt% to 10 wt%, showing that capsules were insensitive to the EC content. The drug loading and EE increased with increasing core to shell ratio. Also, the ratio was 70: 30 when the drug loading and EE deceased. SEM images of microcapsules showed uniform spherical structures with smooth surfaces, with a particle size range distribution between 100 nm(-2).m. The Core-shell and hetero-structures were confirmed using optical micrograph. Release rate for the AWS from the microcapsules was up to 98% within 5 h with pH 2. Comparatively, the release rate for the AWS decreased significantly to 72% and 35%, with pH of 6 and 10 respectively, showing a sustained and prolonged release.
作者机构：
[Qing, Yan; Wu, Yiqiang; Liu, Liu; Tian, Cuihua; Yan, Ning; Li, Xianjun; Li, Lei] Cent South Univ Forestry & Technol, Coll Mat Sci & Technol, Changsha, Hunan, Peoples R China.;[Qing, Yan; Wu, Yiqiang; Li, Xianjun] Cent South Univ Forestry & Technol, Hunan Prov Collaborat Innovat Ctr High Efficiency, Changsha, Hunan, Peoples R China.;[Yan, Ning] Univ Toronto, Fac Forestry, Toronto, ON M5S 1A1, Canada.
通讯机构：
[Qing, Y; Wu, YQ] C;Cent South Univ Forestry & Technol, Coll Mat Sci & Technol, Changsha, Hunan, Peoples R China.;Cent South Univ Forestry & Technol, Hunan Prov Collaborat Innovat Ctr High Efficiency, Changsha, Hunan, Peoples R China.
摘要：
To overcome the poor mechanical strength of thermosensitive hydrogels, cellulose nanofibril (CNF) was used as a reinforcing agent for the preparation of PEG-based thermosensitive hydrogels through radical copolymerization. The maximum bloom and rupture strength of the hydrogel were increased respectively with 37.7% and 52% at CNF content of 0.35 wt%. The dynamic rheological properties further confirmed that CNF played a significant role in the improvement of mechanical strength, especially in elasticity. Due to abundant hydroxyl groups exposed on the surface of CNFs, the obtained hydrogels exhibited a decreasing equilibrium swelling ratio (ESR) and deswelling rate in comparison with untreated hydrogels. However, the water retention ratio (WRR) increased when CNF content increased. In addition, both treated and untreated thermosensitive hydrogels possessed continuous volume phase transition with temperature ranging from 0 to 70 °C. Combined with SEM and ATR-FTIR tests, it was indicated that CNFs contributed to the formation of hydrogen bonding between the copolymer matrix and a tight physical lock by means of an entanglement effect. These composite hydrogels are considered as promising candidates in various potential applications of soft actuators, biosensors, artificial muscles and drug delivery.
作者机构：
[龙柯全; 吴义强; 肖俊华; 李贤军; 左迎峰] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, China
通讯机构：
[Wu, Y.] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, China
作者机构：
[罗莎; 卿彦; Wu Y.; 田翠花] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China;[蔡智勇] Forest Products Laboratory, USDA Forest Service, Madison, 53726, United States;School of Renewable Natural Resources, Louisiana State University, Baton Rouge, 70803, United States;[吴义强] School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, China, School of Renewable Natural Resources, Louisiana State University, Baton Rouge, 70803, United States
通讯机构：
[Wu, Y.] S;School of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, China
作者机构：
[Sun, Xiuxuan; Wu, Qinglin] Louisiana State Univ, AgCtr, Sch Renewable Nat Resources, Baton Rouge, LA 70803 USA.;[Lee, Sunyoung] Korea Natl Inst Forest Sci, Dept Forest Prod, Seoul 130712, South Korea.;[Wu, Yiqiang; Qing, Yan] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Wu, Qinglin] L;[Wu, Yiqiang] C;Louisiana State Univ, AgCtr, Sch Renewable Nat Resources, Baton Rouge, LA 70803 USA.;Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.
摘要：
The influence of nanocellulose on oil well cement (OWC) properties is not known in detail, despite recent advances in nanocellulose technology and its related composite materials. The effect of cellulose nanofibers (CNFs) on flow, hydration, morphology, and strength of OWC was investigated using a range of spectroscopic methods coupled with rheological modelling and strength analysis. The Vom-Berg model showed the best fitting result of the rheology data. The addition of CNFs increased the yield stress of OWC slurry and degree of hydration value of hydrated CNF-OWC composites. The flexural strength of hydrated OWC samples was increased by 20.7% at the CNF/OWC ratio of 0.04 wt%. Excessive addition of CNFs into OWC matrix had a detrimental effect on the mechanical properties of hydrated CNF-OWC composites. This phenomenon was attributed to the aggregation of CNFs as observed through coupled morphological and elemental analysis. This study demonstrates a sustainable reinforcing nano-material for use in cement-based formulations.
摘要：
Self-supporting pH-responsive porous membranes of ethyl cellulose graft poly(2-(diethylamino)) ethyl methacrylate (EC-g-PDEAEMA) were prepared via the Non-Solvent-Induced Phase Separation (NIPS) process from mixtures of THF and DMF. The pH-responsive polymers (EC-g-PDEAEMA) were synthesized via Atom Transfer Radical Polymerization (ATRP) and evidenced by H-1 NMR spectroscopy and FT-IR spectra. The morphologies of the porous films were investigated by scanning electron microscopy (SEM) and polarized optical microscopy. These results indicated that the size and the number of pores in the membranes as well as the flux values were larger along with the decrease of THF content and "Open time." The optimum preparation conditions for microfiltration membrane were obtained.
作者机构：
[刘明; 田翠花; 吴义强; 卿彦; 贾闪闪; 罗莎; 李新功] College of Material Science and Engineering, Centre South University of Forestry and Technology, Changsha, 410004, China
通讯机构：
[Wu, Y.] C;College of Material Science and Engineering, Centre South University of Forestry and Technology, Changsha, China
