Super stretchable chromatic polyurethane driven by anthraquinone chromogen as a chain extenderZhao, Caiyun; Wang, Chaoxia; Wang, Youjiang; Yao, Donggang
doi: 10.1039/c8ra06744apmid: 35520534
A novel polyurethane elastomer (PUE) that exhibited high tensile strength, large elongation at break, great color strength and supreme color fastness was successfully designed and synthesized. The PUEs were prepared with isophorone diisocyanate (IPDI) as hard segments, polycarbonate diol (PCDL)/polytetrahydrofuran glycol (PTHF) as mixed soft segments, and anthraquinone chromogen as the chain extender agent. The relationships between the mechanical properties/color performance and chromogen addition content were investigated. The chromogen actual access rate of the obtained BPUEs was evaluated by UV-Vis. The clear tortuous surface and entanglements were exhibited in PUEs micromorphology structure, indicating a significant reinforcement of mechanical properties. Elongation-at-break and tensile strength reached the maximum value 2394% at 1% (BPUE1) and 18.29 MPa at 5% (BPUE5), respectively, and then decreased as chromogen addition content increased. Mechanical testing results correlate well with XRD and SEM findings, which proved that anthraquinone chromogen induced an improvement in phase separation. Furthermore, BPUE films displayed high color strength and excellent color fastnesses. The rubbing fastness and washing fastness of BPUE1 and BPUE0.5 reached grade 5, respectively. These inspiring findings suggest that PUE films with superb performance have potential to be directly applied in the textile field.
Synergetic effect over flame-made manganese doped CuO–CeO2 nanocatalyst for enhanced CO oxidation performanceZhao, Feng; Li, Shuangde; Wu, Xiaofeng; Yue, Renliang; Li, Weiman; Chen, Yunfa
doi: 10.1039/c8ra09626kpmid: 35520527
CuO–CeO2 nanocatalysts with different amounts of Mn dopping (Mn/Cu molar ratios of 0.5 : 5, 1 : 5 and 1.5 : 5) were synthesized by flame spray pyrolysis (FSP) method and tested in the catalytic oxidation of CO. The physicochemical properties of the synthesised samples were characterized systematically, including using X-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), oxygen-temperature programmed desorption (O2-TPD), hydrogen-temperature programmed reduction (H2-TPR) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). The results showed that the 1Mn–Cu–Ce sample (Mn/Cu molar ratio of 1 : 5) exhibited superior catalytic activity for CO oxidation, with the temperature of 90% CO oxidation at 131 °C at a high space velocity (SV = 60 000 mL g−1 h−1), which was 56 °C lower than that of the Cu–Ce sample. In addition, the 1Mn–Cu–Ce sample displays excellent stability with prolonged time on CO stream and the resistance to water vapor. The significantly enhanced activity was correlated with strong synergetic effect, leading to fine textual properties, abundant chemically adsorbed oxygen and high lattice oxygen mobility, which further induced more Cu+ species and less formation of carbon intermediates during the CO oxidation process detected by in situ DRIFTS analysis. This work will provide in-depth understanding of the synergetic effect on CO oxidation performances over Mn doped CuO–CeO2 composite catalysts through FSP method.
Electrical control of liquid metal amoeba with directional extension formationHu, Liang; Zhao, Xi; Guo, Jiarui; Liu, Jing
doi: 10.1039/c8ra10044fpmid: 35520505
In this study, an electric field was used to regulate and control pseudopodia-like extensions of a liquid metal-Al (LM-Al) droplet in certain directions. The results suggest that in certain electric fields, the LM-Al droplets tend to generate extensions perpendicular to the electric field; the underlying mechanism arises from the specific surface tension imbalance induced by the electric field. The influence of varying electric field intensity and Al content on the LM-Al transformations was also evaluated; the LM-Al droplets displayed specific and distinct behaviors according to each experimental configuration; this further proved the feasibility of using electric fields for controlling LM-Al transformations. The entire study provides a promising and practical method for control of LM amoeba-like transformations, which are valuable for further development of soft robots and devices.
The anti-diarrhea activity of red algae-originated sulphated polysaccharides on ETEC-K88 infected miceLiu, Bo; Liu, Qing-Mei; Li, Gui-Ling; Sun, Le-Chang; Gao, Yuan-Yuan; Zhang, Ya-Fen; Liu, Hong; Cao, Min-Jie; Liu, Guang-Ming
doi: 10.1039/c8ra09247hpmid: 35520502
Polysaccharides from red algae Porphyra haitanensis and Gracilaria lemaneiformis possess various bioactive functions, however, their anti-diarrhea activity remains incompletely defined. In the current study, sulphated polysaccharides were extracted by high pressure treatment plus ethanol precipitation from these two algae, and named PHSP(hp) and GLSP(hp), respectively. PHSP(hp) and GLSP(hp) showed decreased viscosity and molecular weight. Meanwhile, they have a certain immunomodulatory effect on wound healing and migration of RAW264.7 cells. Moreover, they significantly increased the secretion of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). A BALB/c model infected by enterotoxigenic Escherichia coli (ETEC)-K88 was also established to evaluate the anti-diarrhea activity of PHSP(hp) and GLSP(hp). The results showed that PHSP(hp) and GLSP(hp) were able to alleviate mice diarrhea symptoms. Meanwhile, they inhibited the release of pro-inflammatory cytokines and suppressed the secretion of immunoglobulin A via reducing the population of B cells. In addition, the nitroblue tetrazolium levels of mouse serum were decreased. Taken together, PHSP(hp) and GLSP(hp) alleviated the inflammatory response of ETEC-K88-induced diarrhea through both specific and non-specific immunity. Sulphated polysaccharides from red algae may be used as functional food components for remitting diarrhea.
Synthesis of high drug loading, reactive oxygen species and esterase dual-responsive polymeric micelles for drug deliveryWang, Nan; Chen, Xiao-Chuan; Ding, Ruo-Lin; Yang, Xian-Ling; Li, Jun; Yu, Xiao-Qi; Li, Kun; Wei, Xi
doi: 10.1039/c8ra09770dpmid: 35520478
Stimulus-responsive, controlled-release systems are of great importance in medical science and have drawn significant research attention, leading to the development of many stimulus-responsive materials over the past few decades. However, these materials are mainly designed to respond to external stimuli and ignore the key problem of the amount of drug loading. In this study, exploiting the synergistic effect of boronic esters and N-isopropylacrylamide (NIPAM) pendant, we present a copolymer as an ROS and esterase dual-stimulus responsive drug delivery system that has a drug loading of up to 6.99 wt% and an entrapment efficiency of 76.9%. This copolymer can successfully self-assemble into polymer micelles in water with a narrow distribution. Additionally, the measured CMC hinted at the good stability of the polymeric micelles in water solution, ensuing long circulation time in the body. This strategy for increasing the drug loading on the basis of stimulus response opens up a new avenue for the development of drug delivery systems.
I2-catalyzed intramolecular oxidative amination of C(sp3)–H bond: efficient access to 3-acylimidazo[1,2-a]pyridines under neat conditionHuang, Lilan; Yin, Wenqing; Wang, Jian; Gan, Chunfang; Huang, Yanmin; Huang, Chusheng; He, Yimiao
doi: 10.1039/c8ra10118cpmid: 35520479
An efficient and “green” protocol for the synthesis of 3-acylimidazo[1,2-a]pyridines through intramolecular oxidative α-amination of carbonyl compounds has been developed. The reaction proceeds smoothly utilizing I2 as a catalyst and H2O2 as an oxidant under neat condition with broad substrate scope. Several complex nitrogen-containing fused rings are conveniently constructed, which are not easy to access by traditional methods.
Facile and green preparation of hemicellulose-based film with elevated hydrophobicity via cross-linking with citric acidShao, Hui; Sun, Hui; Yang, Biao; Zhang, Huijuan; Hu, Yu
doi: 10.1039/c8ra09937epmid: 35520521
Hemicellulose has shown great potential in food packaging due to its excellent biodegradability and low oxygen permeability. However, its strong hydrophilicity leads to poor moisture resistance and hinders its wide application. To address this issue, herein a ternary carboxylic acid, citric acid (CA), was incorporated into hemicellulose as esterifying agent to form a crosslinking structure via the esterification reaction. The CA-modified hemicellulose films showed an increased contact angle of 87.5° (vs. 40.5° for unmodified film), demonstrating that the hydrophobicity of hemicellulose had been improved significantly. In addition, the esterification/cross-linking modification enhanced oxygen barrier performance with oxygen permeability decreasing from 1053 (cm3 μm) (m2 d kPa)−1 to 1.8 (cm3 μm) (m2 d kPa)−1. Moreover, the tensile strength rose to a peak value and then fell back at higher CA content. Effect of CA addition on elongation at break exhibited an opposite trend. The modified hemicellulose films with 20% CA addition possessed the highest tensile strength and the lowest elongation at break. Morphology observation with scanning electron microscopy indicated that at CA content exceeding 20%, the modified films were dense with a smooth surface, illustrating the improvement of phase compatibility. A possible mechanism for esterification/cross-linking was proposed to elucidate the connection between CA addition and film performances.