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911.
912.
Congrui Qi Bihe Yuan Haoran Dong Kaiyuan Li Sheng Shang Yaru Sun Gongqing Chen Yuanyuan Zhan 《先进技术聚合物》2020,31(5):1099-1109
In order to improve its water resistance and compatibility with polymer matrix, ammonium polyphosphate (APP) is modified with melamine‐trimesic acid (MEL‐TA) aggregates by supramolecular self‐assembly technology. Chemical structure and morphology of APP@MEL‐TA are investigated by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM), respectively. Intumescent flame retardant system of APP@MEL‐TA and charring‐foaming agent is introduced into polypropylene (PP) matrix. The flammability and combustion behavior of PP composites are investigated by limiting oxygen index (LOI), UL‐94 vertical burning, and cone calorimetry tests. In terms of LOI values and cone combustion results, APP@MEL‐TA performs better than pristine APP. Char residue of PP composites is investigated by SEM and Raman spectra. Flame retardant mechanisms are proposed based on thermal decomposition, combustion results, and analysis on char residue. 相似文献
913.
Zhenqian Wei Jun Wu Zongru Liu Yanan Gu Guifang Luan Hejing Sun Qing Yu Sheng Zhang Zhongwei Wang 《先进技术聚合物》2020,31(6):1426-1436
Three commercialized flame retardants, 1,2‐bis(diphenylphosphinoyl)ethane (EDPO), 6,6‐(1,2‐phenethyl)bis‐6H‐dibenz[c,e][1,2]oxaphosphorin‐6,6‐dioxide (HTP‐6123), and hexa‐phenoxy‐cyclotriphosphazene (HPCTP), were used to prepare the flame retardant diglycidyl ether of bisphenol A (DGEBA) epoxy resin (EP) under the same experimental conditions. The effects of Tg, thermal stability, and water absorption properties of EP caused by the three flame retardants were investigated and compared, together with their flame retardant efficiency. Results showed that the introduction of the three flame retardants improved the flame retardant performance of EP but led to decreases in Tg and decomposition temperature. EDPO showed higher flame retardant efficiency than the other two flame retardants. EP/EDPO showed higher thermal stability, better flame retardant performance, higher Tg value, and lower water absorption than EP/HTP‐6123 and EP/HPCTP. The study discovered that EDPO and HTP‐6123 primarily act through the gas phase flame retardant mechanism, while HPCTP is primarily driven by the condensed phase mechanism. 相似文献
914.
Min Zhou Yuxin Qian Jiayang Xie Wenjing Zhang Weinan Jiang Ximian Xiao Sheng Chen Chengzhi Dai Zihao Cong Zhemin Ji Ning Shao Longqiang Liu Yuequn Wu Runhui Liu 《Angewandte Chemie (International ed. in English)》2020,59(16):6412-6419
Peptides have important biological functions. However, their susceptibility to proteolysis limits their applications. We demonstrated here for the first time, that poly(2‐oxazoline) (POX) can work as a functional mimic of peptides. POX‐based glycine pseudopeptides, a host defense peptide mimic, had potent activities against methicillin‐resistant S. aureus, which causes formidable infections. The POX mimic showed potent activity against persisters that are highly resistant to antibiotics. S. aureus did not develop resistance to POX owning to the reactive oxygen species related antimicrobial mechanism. POX‐treated S. aureus is sensitive to common antibiotics, demonstrating no observable antimicrobial pressure or cross‐resistance in using antimicrobial POX. This study highlights POX as a new type of functional mimic of peptides and opens new avenues in designing and exploring peptide mimetics for biological functions and applications. 相似文献
915.
Wen‐Chao Geng Dongmei Zhang Chu Gong Zhihao Li Kevin M. Barraza Jesse L. Beauchamp Dong‐Sheng Guo Xinxing Zhang 《Angewandte Chemie (International ed. in English)》2020,59(31):12684-12688
The oxidation of antioxidants by oxidizers imposes great challenges to both living organisms and the food industry. Here we show that the host–guest complexation of the carefully designed, positively charged, amphiphilic guanidinocalix[5]arene pentadodecyl ether (GC5A‐12C) and negatively charged oleic acid (OA), a well‐known cell membrane antioxidant, prevents the oxidation of the complex monolayers at the air–water interface from two potent oxidizers hydroxyl radicals (OH) and singlet delta oxygen (SDO). OH is generated from the gas phase and attacks from the top of the monolayer, while SDO is generated inside the monolayer and attacks amphiphiles from a lateral direction. Field‐induced droplet ionization mass spectrometry results have demonstrated that the host–guest complexation achieves steric shielding and prevents both types of oxidation as a result of the tight and “sleeved in” physical arrangement, rather than the chemical reactivity, of the complexes. 相似文献
916.
917.
Hongfeng Li Peng Wu Yawen Xiao Meng Shao Yu Shen Yun Fan Huanhuan Chen Ruijie Xie Wenlei Zhang Sheng Li Jiansheng Wu Yu Fu Bing Zheng Weina Zhang Fengwei Huo 《Angewandte Chemie (International ed. in English)》2020,59(12):4763-4769
Metal–organic frameworks (MOFs) are promising materials with fascinating properties. Their widespread applications are sometimes hindered by the intrinsic instability of frameworks. However, this instability of MOFs can also be exploited for useful purposes. Herein, we report the use of MOFs as metal ion precursors for constructing functional nanocomposites by utilizing the instability of MOFs. The heterogeneous growth process of nanostructures on substrates involves the release of metal ions, nucleation on substrates, and formation of a covering structure. Specifically, the synthesized CoS with carbon nanotubes as substrates display enhanced performance in a lithium‐ion battery. Such strategy not only presents a new way for exploiting the instability of MOFs but also supplies a prospect for designing versatile functional nanocomposites. 相似文献
918.
919.
Shipeng He Guoqiang Dong Yu Li Shanchao Wu Wei Wang Chunquan Sheng 《Angewandte Chemie (International ed. in English)》2020,59(8):3028-3032
As one of the most aggressive and lethal human malignancies with extremely poor prognosis, there is an urgent demand of more effective therapy for the treatment of pancreatic cancer. Reported here is a new, effective therapeutic strategy and the design of small‐molecule inhibitors that simultaneously target bromodomain and extra‐terminal (BET) and histone deacetylase (HDAC), potentially serving as promising therapeutic agents for pancreatic cancer. A highly potent dual inhibitor ( 13 a ) is identified to possess excellent and balanced activities against BRD4 BD1 (IC50=11 nm ) and HDAC1 (IC50=21 nm ). Notably, this compound shows higher in vitro and in vivo antitumor potency than the BET inhibitor (+)‐JQ1 and the HDAC inhibitor vorinostat, either alone or and in combination, highlighting the advantages of BET/HDAC dual inhibitors for more effective treatment of pancreatic cancer. 相似文献
920.
Sulfonylation of alkenes through photoredox‐catalyzed functionalization of alkenes with thiourea dioxide under visible‐light irradiation is achieved. The reaction of alkenes, thiourea dioxide and electrophiles provides a green and efficient access to alkyl sulfones and sulfonamides. A broad reaction scope is presented with good functional group compatibility and excellent regioselectivity. A plausible mechanism involving a radical addition process with sulfur dioxide radical anion (SO2‐) derived from the oxidation of sulfur dioxide anion (SO22–) is proposed, which is supported by fluorescence quenching experiments. 相似文献