桑蚕丝素蛋白的结构、形态及其化学改性

通过对桑蚕吐丝机构的描述,着重从高分子科学的角度介绍桑蚕丝和蚕丝素蛋白大分子的组成、形态及各种化学、物理性质,讨论了蚕丝素蛋白的纤维化机理,并简述了丝索蛋白纤维的化学接枝改性及其应用。     

Na2CaP2O7, a new catalyst for the synthesis of unsaturated arylsulfones

The synthetic diphosphate Na₂CaP₂O₇ is a new basic catalyst for the synthesis of unsaturated arylsulfones. The condensation was carried out under mild conditions at room temperature in methanol or ethanol. The optimum of the catalyst's activity is reached when water is added, leading to good yields.     

Single Atoms of Iron on MoS2 Nanosheets for N2 Electroreduction into Ammonia

Efforts have been devoted to achieving a highly efficient artificial synthesis of ammonia (NH₃). Reported herein is a novel Fe-MoS₂ catalyst with Fe atomically dispersed onto MoS₂ nanosheets, imitating natural nitrogenase, to boost N₂ electroreduction into NH₃ at room temperature. The Fe-MoS₂ nanosheets exhibited a faradic efficiency of 18.8 % with a yield rate of 8.63 μg mg_cat.⁻¹ h⁻¹ for NH₃ at −0.3 V versus the reversible hydrogen electrode. The mechanism study revealed that the electroreduction of N₂ was promoted and the competing hydrogen evolution reaction was suppressed by decorating the edge sites of S in MoS₂ with the atomically dispersed Fe, resulting in high catalytic performance for the electroreduction of N₂ into NH₃. This work provides new ideas for the design of catalysts for N₂ electroreduction and strengthens the understanding about N₂ activation over Mo-based catalysts.     

Thermal and thermoxidative degradations of starch and thermosensitive starch-g-BAM copolymers

Summary Thermal degradation under N₂atmosphere and thermoxidative degradation under air atmosphere of increasingly grafting efficiency values (i.e. GE%=0.0 to 35.5) for starch and starch grafted with N-tert-butylacrylamide thermosensitive copolymers (starch-g-BAM) by Ozawa and Kissinger methods using thermogravimetric analysis (TG) and differential scanning calorimetry techniques (DSC) at 10, 30 and 50% mass losses respectively have been studied. Influence of physical inter and intra molecular interactions on grafting and consequently on activation energy of degradation (E_a,d) was investigated using Ozawa's method, whereas linear dependence of E_a,don GE% by scaling relations using Kissinger's method was determined. Furthermore, the thermoxidative degradation induces the possibility of molecular rearrangement, cyclization and partial crosslinking that is deduced from the activation energy of degradation (E_a,d) and residual mass of TG profile. Thermal stability of starch does not alter as a result of different grafting efficiency percentages.     

GMA熔融接枝EPDM的研究

以甲基丙烯酸缩水甘油酯（ＧＭＡ）为接枝单体，过氧化二异丙苯（ＤＣＰ）为引发剂，对三元乙丙胶（ＥＰＤＭ）进行了熔融接枝，在烃链上引入极性基团，以改善ＥＰＤＭ与极性聚合物的相容性。用差示扫描量热计（ＤＳＣ）研究了ＧＭＡ的聚合温度，用富里叶红外（ＦＴ－ＩＲ）、凝胶渗透色谱（ＧＰＣ）对接枝产物进行了表征。实验结果表明，产物的接枝率和凝胶量可以通过反应条件（温度、时间、反应物组成及加料方式）来控制。     

Dielectric properties of plasma polymerized PVCa and composite PVCa:Au films

Dielectric properties of plasma polymerized PVCa and composite PVCa:Au films had been analyzed in the frequency range from 10 to 10⁵ Hz. In order to explain experimental data obtained the modification of Maxwell-Garnett and Bruggeman self-consistent models for the case of three-component composite has been done. The theoretical analysis performed allows to determine peculiarities of dielectric behavior of a three-component system, as well as to disclose the procedure of evaluation of third-component parameters. Results of this analysis are in agreement with experimental ones.