摘要：Poly(dibutyl itaconate-co-isoprene-co-methacrylic acid)(PDIM) elastomer was designed and synthesized by redox emulsion polymerization under mild conditions. PDIM has high molecular weight, relatively high yield, and low glass transition temperature(Tg). The structure of PDIM was determined by FTIR and NMR, and the carboxyl content was obtained by titration in a non-proton solvent. Tensile strength and elongation at break increased with increasing carboxyl content. In addition, the interaction between PDIM and silica was elucidated by rubber process analyzer(RPA) and TEM, and the results showed that the silica-PDIM interaction was strong, but the silica-silica interaction was weak.

摘要：GaN-based laser diodes(LDs)extend the wavelength of semiconductor LDs into the visible and ultraviolet spectrum ranges,and are therefore expected to be widely used in quantum technology,bio&medical instruments,laser displays,lighting and materials *** development of blue and green LDs is still challenging,even though they are based on the sameⅢ-nitride materials as GaN-based lightemitting *** challenges and progress of GaN-based blue and green LDs are reviewed from the aspects of epitaxial growth and layer structure *** to large differences in lattice constants and growth conditions for InN,GaN,and AlN,considerable effort is required to improve the quality of InGaN multiple quantum well(MQW)gain medium for blue and especially green LDs.p-type doping profiles,conditions and layer structures are critical to reduce the internal losses and to mitigate the degradation of InGaN *** injection is also a key issue for GaN-based LDs.

摘要：采用分子动力学模拟构建了可修复的物理交联网络/共价键交联网络双网络的粗粒度模型,发现在高温下通过交联反应形成的化学交联网络符合动力学关系,与实验上的交联反应一致.本文主要通过改变物理网络中交联点间的非键相互作用强度和共价键网络的交联度,来实现性能的调控.结果表明,物理网络中交联点间的非键相互作用强度只有超过5.0ε时,链段才会出现有效聚集、形成物理交联点,以此提升其力学性能.通过提升共价网络交联度,物理网络对应力的贡献也显著提升,体系力学性能明显提高.同时,可逆的物理网络赋予了材料良好的自修复性能.本工作将为具有自修复功能的多重弹性体网络的设计提供指导.

摘要：Currently adopted cross-linking methods in rubber industry are suffering from variable persistent issues, including the utilization of toxic curing packages, release of volatile organic compounds (VOCs) and difficulties in the recycling of end-of-life materials. It is of great importance to explore a green cross-linking strategy in the area. Herein, we report a new ‘‘green" strategy based on hydrolyzable ester cross-links for cross-linking diene-typed elastomers. As a proof of concept, a commercial carboxylated nitrile rubber (XNBR) is efficiently cross-linked by a bio-based agent, epoxidized soybean oil (ESO), without any toxic additives. ESO exhibits an excellent plasticization effect and excellent scorch safety for XNBR. The crosslinking density and mechanical properties of the ESO-cured XNBR can be manipulated in a wide range by changing simply varying the content of ESO. In addition, zinc oxide (Zn O) performs as a catalyst to accelerate the epoxide opening reaction and improve the cross-linking efficiency, serving as reinforcement points to enhance the overall mechanical properties of the ESO-cured XNBR. Furthermore, the end-oflife elastomer materials demonstrate a closed-loop recovery by selectively cleaving the ester bonds, resulting in very high recovery of the mechanical performance of the recycled composites. This strategy provides an unprecedented green avenue to cross-link diene elastomers and a cost-effective approach to further recycle the obtained cross-linked elastomers at high efficiency.

摘要：Although dielectric elastomer(DE)with substantial actuated strain(AS)has been reported 20 years ago,its scientific understanding remains *** most accepted theory of DE,which is proposed in 2000,holds the view that AS of DE is induced by the Maxwell *** to this theory,materials have similar ratios of permittivity and Young’s modulus should have similar AS,while the experimental results are on contrary to this theory,and the experimental AS has no relationship with ideal ***,a new dipole-conformation-actuated strain cross-scale model is proposed,which can be generally applied to explain the AS of DE without *** to this model,several characteristics of an ideal DE are listed in this work and a new DE based on polyphosphazene(PPZ)is *** AS of PPZ can reach 84%without any *** last,a PPZ-based all soft artificial heart(ASAH)is built,which works in the similar way with natural myocardium,indicating that this material has great application potential and possibility in the construction of an ASAH for heart failure(HF)patients.

摘要：橡胶是一种非线性黏弹性材料,准确描述其非线性黏弹性力学响应的本构方程是橡胶材料及制品设计优化的关键。文中基于超弹性模型和并行流变模型(PRF)描述了橡胶材料的非线性黏弹性响应特征,重点探讨了由实验数据确定PRF本构方程材料参数的方法。首先通过单轴拉伸实验数据拟合得到超弹性模型,将应力松弛实验数据拟合得到表征材料线性黏弹性的模型-Prony级数,再将Prony级数转化为初始的PRF模型,进而不断优化得到PRF模型的准确材料参数,最后进行实验验证。结果表明,PRF模型计算的不同应变下的应力松弛数据与实验数据之间的误差仅为0.067%,PRF能准确地描述橡胶材料非线性响应的应力松弛行为。

摘要：橡胶的交联(硫化)是其获得高弹性的前提,只有经过交联的橡胶才具有实用价值。但是,目前橡胶工业广泛使用的传统交联方法存在以下几个难以避免的固有问题:(1)硫化体系中会包含有毒的物质;(2)硫化加工过程会释放有毒且难闻的“硫化烟气”;(3)废弃的橡胶制品回收再利用十分困难,带来严重的“黑色污染”。为了彻底解决上述问题,提出一种橡胶材料“绿色交联”的概念以及设计策略具有重要意义。文中首先介绍了橡胶传统硫化方法存在的问题,重点综述了橡胶新型绿色交联策略的研究进展,主要包括以环氧化或羧基化橡胶中的环氧基团或羧基作为交联点,选择生物基二羧酸或环氧大豆油作为绿色交联剂替代硫磺,制备“酯基”交联结构的设计思路。最后,对橡胶绿色交联策略面临的挑战和发展方向进行了展望。

摘要：基于瞬态热线法,通过自主设计的松密度-导热系数实验台,能准确测量导热系数与其松密度之间的关系。文中分别测量了松密度大小对普通胶粉、具有相同含量的松焦油、煤焦油的胶粉导热系数的影响。结果表明,粉体的导热系数大小与松密度呈线性关系:随着粉体材料的松密度增加,其导热系数线性增强。比较发现,含煤焦油和松焦油的胶粉的导热系数高于普通胶粉导热系数;相同松密度下,含煤焦油的胶粉导热系数高于含松焦油的胶粉导热系数,普通胶粉导热系数最低。通过分析表明,这种胶粉导热性能的差异与颗粒之间接触面积、空气含量及颗粒表面不同含油层的厚度相关。

摘要：【目的】自小麦全蚀病自然衰退土壤分离得到的荧光假单胞菌(Pseudomonas fluorescens)2P24,可防治多种由植物病原菌引起的土传病害。菌株2P24具有群体感应(quorum-sensing,QS)系统PcoI/PcoR,该系统影响生防菌2P24生物膜的形成以及其在小麦根围的定殖能力,从而影响2P24的生防能力。本文利用遗传学方法进一步研究了2P24中QS系统的调控途径。【方法】将QS系统信号合成基因pcoI的转录报告质粒p970Gm-pcoIp转入gacA基因突变菌株PM201中,再利用Tn5转座子对该菌株进行随机突变,筛选影响pcoI基因表达的调控因子。【结果】根据菌落颜色的变化筛选到2株突变菌株。Tn5插入位点和基因序列分析表明这2个突变体中Tn5破坏了同一个基因mvaT;设计引物利用PCR方法从2P24基因组中获得mvaT基因及其同源基因mvaV。转录融合报告实验表明:与野生菌株2P24相比,mvaT及mvaV突变体中pcoI基因的表达和N-乙酰高丝氨酸内酯的产量显著提高;HPLC试验表明mvaT和mvaV基因影响抗生素2,4-二乙酰基间苯三酚的合成。细菌双杂交试验证实,MvaT蛋白和MvaV蛋白在体内发生自身互作,这两个蛋白也可相互作用。【结论】以上结果表明mvaT和mvaV参与调控生防假单胞菌2P24的PcoI/PcoR群体感应系统,并可能影响其生防功能基因的表达。