树脂改性用低顺式聚丁二烯橡胶研究进展

综述了树脂改性用低顺式聚丁二烯橡胶(LCBR)的合成路线、生产工艺、国内生产装置的情况及国内外LCBR的研究现状,同时对树脂改性用LCBR的研究方向进行了展望。LCBR生产工艺主要包括连续聚合工艺及间歇聚合工艺,国内树脂改性用LCBR产品仍存在技术瓶颈。对于树脂改性用LCBR的研究主要集中在降低凝胶含量及低胶液黏度产品的开发方面。     

不同形貌碳酸钙的制备及其对PVC薄膜力学性能的影响

选用偏钒酸铵、聚乙二醇、十六烷基三甲基溴化铵、焦磷酸钠十水和聚乙烯吡咯烷酮作为碳酸钙形貌控制剂,以氯化钙和碳酸钠为原料,用氯化法制备得到了片状、菱形、棒状、球状和立方体状5种不同形貌碳酸钙微粒,并研究不同形貌碳酸钙颗粒形态对软质聚氯乙烯（PVC）薄膜力学性能的影响。结果表明,不同形貌碳酸钙均提高了PVC薄膜的力学性能,PVC薄膜拉伸强度和断裂伸长率均提高显著;其中,棒状形貌碳酸钙对PVC薄膜力学性能的提高效果最好,拉伸强度达到了27.11 MPa;菱形碳酸钙改性PVC薄膜的断裂伸长率最高,为98.23 %。     

Green Synthesis,Characterization, and Properties of Acyl Lysine,Serine, Threonine,and Methionine Derived from Three Types of Natural Oils

The development of environmentally benign products has been the subject of growing interest in the field of surfactant chemistry. Acyl amino acid surfactants bearing lysine, serine, threonine, and methionine residues were synthesized using natural oils extracted from coconut, palm kernel, and soybean as acyl donors. The chemical structures were confirmed by high-performance liquid chromatography (HPLC/MS) and infrared (IR) spectra. Their surface activities, ion-specific effects, detergency, and foam properties were studied systematically. The critical micelle concentration (CMC) values depend significantly on amino acid and oil types and follow the orders: (i) Lys > Thr ≈ Ser > Met and (ii) Coconut ≈ Palm kernel > Soybean oil. Interestingly, the ion-specific effects showing that the γ_CMC value decreases with increasing counterion size and hydrophobicity were observed, and the results were consistent with the famous Hofmeister series. The detergency ability of acyl amino acid surfactants is better than multiple traditional surfactants in distilled water. Although the detergency ability of our products for oil-soiled swatches decreased significantly in hard water, this problem was solved by the C-Lys-Na/AES mixed system showing excellent synergistic effects. Excellent foamability and foam stability were achieved for acyl threonine and serine bearing hydroxyl groups on their headgroups, suggesting that the packing of these surfactants at the air–water interface was assisted by hydrogen bonding.     

掺油中空玻璃密封胶的性能评价

通过对比实验,比较了掺油和未掺油中空玻璃密封胶的耐久性、热老化性能、粘接性能以及与热熔丁基密封胶的相容性,比较了其制造的中空玻璃的耐紫外辐照性能.深入分析了掺油中空玻璃密封胶所带来的一系列严重的质量问题及其在使用过程中的危害性.     

从实例谈压力容器及管道SCC及其防护

列举及分析了压力设备典型SCC失效案例,最后从设备成形前(即设计阶段)、成形中(即制造阶段)、成形后(即设备使用阶段)详细介绍了压力设备SCC防护措施。     

非均匀组织FeMnCoCr高熵合金的微观结构和力学性能

提出了一种简单的高熵合金加工工艺,即对Fe-Mn系高熵合金采用中等形变量冷轧和中温短时退火相结合的方法,获得了由晶粒尺寸为数十微米的形变晶粒和超细尺度再结晶晶粒组成的非均匀结构.通过向合金中同时引入由高密度位错、晶粒细化、析出相、ε-马氏体、α-马氏体和回复孪晶等微观结构特征及变形过程中持续发生的形变孪生、ε-马氏体相...     

主动弯曲网壳结构综述

主动弯曲网壳结构的成形方式极为特殊,其初始形态为由剪式铰连接的双向通长平面网格,通过对平面网格的弯曲实现结构曲面造型.由于剪式铰允许发生平面内转动,因此结构可通过四边形网格角度的变化来适应自身形态的变化.主动弯曲网壳结构最早由德国著名工程师Frei Otto于上世纪六十年代提出,但由于找形复杂、施工困难等因素,全球仅有...     

Cf/SiC复合材料低温铣削工艺优化研究

对超硬金刚石刀具低温铣削Cf/SiC复合材料进行工艺优化研究,主要研究聚晶金刚石刀具低温铣削Cf/SiC复合材料过程中,低温冷却介质(干冰、液氮)和冷却工艺参数(阀体出口压力和喷嘴喷射角度)对切削力、加工表面完整性和切屑的影响规律.研究表明:在干冰、液氮低温介质的冷却作用下,工件的加工表面质量得到了较大提高,主切削力显...     

现代战争中的电子干扰和反干扰技术

介绍现代战争中的电子干扰和反干扰技术、提高干扰与抗干扰能力的相关新技术措施,以及国内外现有的新电子干扰设备,描述电子对抗的发展趋势,同时也指出了仍存在的一些问题.