Silicone emulsions and surfactants

This review is intended to supply the practicing chemist with a working knowledge of the chemistry of silicone compounds. It has been divided into two parts, the first dealing with basic chemistry of silicones [O'Lenic, A.J., JSD 2, 229 (2000)] and the second with silicone-based surfactants, specifically dimethicone copolyols and their derivatives. This is the second part of the review. Although silicone compounds have been known for over 50 yr, the chemistry of these materials remains elusive to the average formulating chemist. This is indeed unfortunate, since the chemistry of the silicon atom and silicone compounds is every bit as wide in scope and rich in content as the chemistry of the carbon atom and the surfactant chemistry upon which it is based. This article will deal with the various methods of delivering silicone from aqueous systems. The two approaches are (i) to make emultions that contain silicone oil and a surfactant pair and the (ii) to make modify the molecule chemically to make the product more water-compatible. Both approaches find applications in a variety of industrial applications, with different challenges to the formulator.     

微米级聚苯乙烯/聚硅氧烷核壳微球的制备、表征及其作为光散射剂的应用

在乙醇/水混合溶剂中采用分散聚合法制备出微米级聚苯乙烯微球,将聚苯乙烯核微球与甲基三甲氧基硅烷的水解溶液混合,加入氨水使硅烷水解产物在核表面缩合交联,制备出微米级聚苯乙烯/聚硅氧烷核壳微球.采用TEM、粒径分布仪、EDX、TG等对核壳微球的形貌、粒径、表面成分和热失重进行了表征.将核壳微球作为光散射剂添加在聚甲基丙烯酸甲酯（PMMA）树脂中,制备出性能良好的光散射材料.当SS6核壳微球的添加浓度为1%（质量）时,制得的PMMA样片（2 mm）的雾度为88.16％,透光率为72.5％;当SS6添加浓度为2%（质量）时,其雾度为92.13％.     

超支化聚硅氧烷/Ni/石墨烯纳米带/BMI复合材料的摩擦学性能研究

为了改善石墨烯与双马来酰亚胺(BMI)树脂基体的相容性并使其在摩擦过程中快速形成高质量自润滑转移膜,本文以超支化聚硅氧烷(HBPSi)和纳米Ni粒子共同改性石墨烯纳米带(GNRs)制备出HBPSi/Ni/GNRs复合粒子,并将其引入BMI树脂中制备出HBPSi/Ni/GNRs/BMI复合材料。采用FT-IR、SEM、TEM、摩擦磨损试验机及分子动力学模拟对复合粒子的结构、形貌及引入量和复合材料的摩擦学性能的影响进行了研究,并探究了其摩擦磨损机理。结果表明：HBPSi和Ni纳米粒子成功负载到GNRs表面。HBPSi/Ni/GNRs相比于GNRs能够显著提升其BMI复合材料的摩擦学性能。当HBPSi/Ni/GNRs添加量为0.6 wt%时,HBPSi/Ni/GNRs/BMI复合材料的摩擦系数和体积磨损率均降至最低值,分别为0.18和1.9×10_-6 ^mm₃^/(N.m)。此外,分子动力学结果表明,HBPSi/Ni/GNRs与BMI强的界面作用是导致其复合材料抗剪切能力提升的关键。     

Divinyl-terminated polysiloxane as an effective polyacrylates modifier for pigment printing: A study with different molecular weights and quantities

Polyacrylates binder is used as an environmental approach for pigment printing. However, the poor water resistance and abrasive resistance of it makes this technique limited. In this study, divinyl-terminated polysiloxane (Divi-PDMS) had been used to modify polyacrylates by miniemulsion polymerization. The conversion and coagulation of miniemulsion polymerization were evaluated by gravimetry method, the colloid properties of prepared latexes were obtained and the structures were confirmed by Fourier transformed infrared spectroscopy and NMR. Surface properties of latex films were investigated in terms of dynamic water contact angle, water absorption, and mechanical tensile properties. The results show that the polymerization has good stability, and the product has good phase separation of polysiloxane, which results in increased hydrophobicity and toughness of the film. The film with low-molecular weight and 8% dosage of Divi-PDMS has better hydrophobicity and toughness. The product is applied to pigment printing with better wet rubbing fastness and soft handle compared with the unmodified binder. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47961.     

含氮聚硅氧烷配位体及其Cu^2＋络合物的介电性能

研究了ｎ－β（氨乙基）－γ（氨丙基）三乙氧基硅烷（ＮＨ２（ＣＨ２）２ＮＨ（ＣＨ２）３Ｓｉ（ＯＥｔ）３）与二甲基二乙氧基硅烷（ＣＨ３）２Ｓｉ（ＯＥｔ）２）共水解，制备含（ＣＨ２）３ＮＨ（ＣＨ２）２ＮＨ２功能基的聚硅氧烷配位体，用ＩＲ，＾１ＨＮＭＲ和元素分析法对水解产物分析证明，ＮＨ２（ＣＨ２）２ＮＨ（ＣＨ２）３Ｓｉ（ＯＥｔ）３与（ＣＨ３）２Ｓｉ（ＯＥｔ）２进行了共水解反应，而且水解程度随ＮＨ２（ＣＨ     

非水液膜初探

首次提出了非水液膜的要领概念。从分析现有液膜体系的构成和局限性出发，提出了建立非水液膜体系的可能途径，并得到初步成功，考究了非水液膜对有机物的传输效率和选择性。     

聚硅氧烷链段分子量对改性聚丙烯酸酯性能的影响

采用双端丙烯酰氧基聚醚硅油改性聚丙烯酸酯,研究聚硅氧烷链段分子量对改性胶膜吸水率、水接触角、力学性能及涂料印花性能的影响。并用扫描电镜和原子能谱仪对胶膜表面进行测定。结果表明：聚硅氧烷链段分子量为1600和2300时,胶膜具有较低的吸水率、较高的水接触角和断裂功,涂料印花织物手感柔软,干、湿摩可达4级;聚硅氧烷链段的分子量过大,胶膜焙烘过程中有机硅相分离和富集团聚增多,胶膜的吸水率变大,其断裂功变小,涤料印花性能变差．     

Polysiloxane Cross-Linked Mechanically Stable MXene-Based Lithium Host for Ultrastable Lithium Metal Anodes with Ultrahigh Current Densities and Capacities

The applications of lithium metal anode are limited by uncontrollable lithium dendrite growth and infinite volume changes during cycling. These fundamental issues are exacerbated at high cycling current densities and capacities. Herein, a mechanically stable and resilient lithium metal host is fabricated by covalently cross-linking a highly-conductive and lithiophilic MXene/silver nanowire scaffold through a silylation reaction between MXene nanosheets and polysiloxane. Compared with the control sample (an MXene scaffold assembled by weak van der Waals forces), the covalently cross-linked MXene scaffold displays excellent mechanical strength and resilience, which is conducive to buffer the large internal stress fluctuations generated during rapid and deep lithium plating-stripping and guaranteed that the integrated framework structure is maintained during long-term charging-discharging cycles. When used in a symmetric cell, the lithium composite anode based on the covalently cross-linked MXene host affords an unprecedented cyclic lithium plating-stripping stability of a record-high 3000 h lifespan at an ultrahigh current density (20 mA cm⁻²) and areal capacity (10 mAh cm⁻²). When this composite anode is coupled with a LiNi_0.5Co_0.2Mn_0.3O₂ cathode, the full cell delivers an ultrahigh rate of 10 C for up to 1000 cycles, with an average capacity decay of 0.043% per cycle and a stable Coulombic efficiency of 98.7%.     

线型聚硅氧烷改性聚醚型聚氨酯/环氧树脂互穿聚合物网络

以端羟基聚硅氧烷(PDMS)、4,4,-二苯甲烷二异氰酸酯(MDI)、聚醚多元醇为原料制得端异氰酸酯基(-NCO)聚氨酯预聚体,再与环氧树脂E-44反应制得一系列聚硅氧烷改性聚氨酯/环氧树脂互穿聚合物网络。通过红外光谱、接触角、拉伸试验、动态力学分析、扫描电子显微镜对聚合物体系的结构与性能进行了研究和表征。实验结果表明,聚硅氧烷的引入使得互穿聚合物网络的表面疏水性增强,表面自由能降低,拉伸强度下降但断裂伸长率升高。随着聚硅氧烷用量的增加,聚合物体系的玻璃化转变温度从-45℃提高到了-36℃。     

A comparative study on mechanical properties of carbon fiber/PEEK composites

The aim of this work was to improve mechanical properties such as flexural strength and interlaminar shear strength (ILSS) of polyetheretherketone (PEEK) thermoplastic polymer which has very high processing temperature due to its high melting temperature. Carbon fiber (CF) surface was modified by two different methods: oxidative and non-oxidative. Piranha solution and chromate solution were used for chemical treatment (oxidative treatment), and silicone based polymers were used for polymer coating (non-oxidative). The changes on the surface structure and surface chemistry were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy (FTIR), respectively. FTIR results indicate that coating fibers decreases carbon element content, whereas increases the oxygen and silicone content as well as their functional groups on the surface. Flexural strength and ILSS properties of CF/PEEK composites were measured according to ASTM D-790 and ASTM D2344, respectively.