衰减全反射红外光谱法在高分子结构分析中的应用

衰减全反射作为红外光谱法的重要实验方法之一,快速、简单、不破坏样品,极大地扩展了红外光谱的应用领域。用红外光谱技术分析了几种常见高聚物的红外光谱图,通过这些红外光谱图的特征峰可以有效确定聚合物的类型。最后以乙烯-醋酸乙烯酯共聚物(EVA)为例讨论了该技术在共聚物或共混物组成测定方面的应用。     

硅气凝胶/空心玻璃微珠保温涂料的研制

硅气凝胶具有纤细纳米网络结构,是迄今为止导热系数最低的固体材料。本研究从传热学机理出发,以硅气凝胶、空心玻璃微珠为功能填料,辅以无机高分子基料、填料和助剂,经特殊工艺制得了保温涂料,对涂料的性能进行了检测,并对硅气凝胶保温涂料的保温机理进行了分析,该涂料将在建筑、输送管道、窑炉、异型件等方面有广阔的应用前景。     

国外纤维增强热塑性塑料发展概况(V)

纤维增强热塑性塑料（FRTP）因其重量轻,抗冲击性和疲劳韧性好,成型周期短,可循环利用等诸多优点,近年在稳定发展,已进入汽车、轨道交通、运输、航空航天、能源、基础设施、建筑、电气电子、防卫、船艇、工业、医疗、体育娱乐等多种应用市场。有关厂商为之研发了各种形式的FRTP材料、产品和FRTP最终制品的成型工艺。     

相转化法制备聚砜膜研究进展

系统概述了相转化法制备聚矾膜时聚矾含量、添加剂、凝固浴及铸膜液在空气中的蒸发时间对其结构和性能的影响。随着聚矾含量的增加,膜结构从疏松向致密转变;在铸膜液中添加适合的添加剂可制备适当结构和渗透性能的聚矾膜;在凝固浴中添加适量的溶剂,可有效抑制膜内大孔结构的形成;空气中蒸发时间的增大时,膜表面趋于疏松,当增加到一定程度后基本趋于稳定。还综述了相转化法制备聚矾膜时聚矾含量、添加剂、凝固浴及铸膜液在空气中的蒸发时间对其结构和性能的影响。     

Effect of conductive layer on the performance of gel electrolyte-based supercapacitors

Solid-state electrolytes such a further novel finding is going to have great importance because of the disadvantages of liquid electrolytes such as electrochemical instability, low ion selectivity, and interface contact. It is anticipated that the use of solid-state electrolytes including supercapacitors (SCs) will become widespread with decreasing self-leakage and environmental damage more than liquid electrolytes. In this study, SCs with graphene/PEDOT: PSS coated electrodes and binary PVA gel electrolytes with a conductive layer were designed and the electrochemical performance of the configurations was characterized. The effects of the conductive layer between binary electrolytes and the concentration of the KOH solution in the electrolytes were studied. It was observed that the conductive layer used between the gel electrolytes causes additional charging at the electrolyte/conductive layer interface and behaves like a serially connected capacitor to the double-layer capacitor. Interestingly, at a slow sweep rate (5 mV/s), the specific capacitance values of the assembled SCs decreased when a conductive layer was used but it increased when the sweep rate was fast (100 mV/s).     

Effects of subphase pH and temperature on the interfacial behavior of double hydrophilic diblock copolymer PDEGMA-b-PDIPAEMA

The aggregation behavior of two pH- and temperature-responsive diblock copolymers of poly[di-(ethylene glycol) methyl ether methacrylate]-block-poly[2-(diisopropylamino) ethyl methacrylate] (PDEGMA-b-PDIPAEMA) at the air/water interface and the structures of their Langmuir–Blodgett (LB) films were studied by the Langmuir monolayer technique and atomic force microscopy, respectively. At the air/water interface, PDEGMA-b-PDIPAEMA tends to form the core-shell-corona micellar structure composed of a PDIPAEMA main chain core, an amino ethyl ester shell, and a PDEGMA corona. Under acidic, neutral, and alkaline conditions, PDIPAEMA blocks are completely protonated, partially protonated, and completely non-protonated, respectively, and the protonated amino ethyl ester groups are immersed in water before monolayer compression, whereas PDEGMA coronas are adsorbed at the interface. At pH 3, 7, and 10, the limiting areas (A₀) for PDEGMA42%-PDIPAEMA58% (weight percents) and PDEGMA55%-PDIPAEMA45% are 8.2/10.2/14.0 and 6.7/8.3/8.4 nm², respectively. The A₀ values of the former copolymer are larger than those of the latter. This is because the shells in the former copolymer are denser due to the higher polymerization degree of PDIPAEMA blocks, providing greater steric hindrance for PDEGMA coronas and making the latter more extended at the interface. In contrast to other copolymer systems, the effect of temperature on the isotherms of PDEGMA-b-PDIPAEMA is less obvious.     

Enhancement of the hydrophobicity and oleophobicity of a polyurethane coating using a fluorine-free polyfarnesene-based polyol

The development of hydrophobic and oleophobic surfaces on materials has attracted significant attention in various research fields. Fluoropolymers, which possess low surface energy and are both highly hydrophobic and oleophobic in nature, are widely used to enhance the liquid repellency of materials. However, during fluoropolymer manufacture, fluorine-containing compounds are released into the environment; thus, alternatives to fluoropolymers are required for maintaining environmental safety and realizing a sustainable society. Notably, the development of such alternative materials has been limited. Thus, we herein report the application of a novel polyurethane (PU) coating synthesized from bio-based raw materials. The prepared hydrogenated polyfarnesene PU (HHPF PU), which possesses an amorphous bottlebrush-like polyalkyl structure, was found to exhibit higher hydrophobicity and oleophobicity than polytetrafluoroethylene (PTFE), which is a typical low-surface-energy material. The water and n-hexadecane contact angles of the HHPF PU were determined to be 119° and 68°, respectively, whereas those of PTFE were 108° and 46°, respectively. In addition, the density depth profile of the PU thin film was confirmed through x-ray reflectometry. This study provides a novel approach for enhancing the hydrophobicity and oleophobicity of materials using bottlebrush-like polyalkyl structure instead of fluorine.     

Mechanically robust and highly electrochemical performance of polyethylene oxide gel polymer electrolyte

Synthesizing high-performance of gel polymer electrolytes (GPEs) with simple methods and common materials has long been a crucial concern for lithium-ion batteries. Here, the poor mechanical properties of polyethylene oxide (PEO) based GPEs were overcome by introducing strong hydrogen bond between PEO and polyacrylic acid (PAA). Easy-available PEO/PAA membranes were prepared though hot processing approach without use of organic solvent during all processes. The mechanical properties and crystalline of dry composites could be tuned by the addition content of PAA. After quick absorbing electrolyte in 30 min, the tensile strength and elongation at break of the GPEs composites are ranged from 0.07 to 0.63 MPa, and 525% to 722%. Moreover, the lithium-ion conductivity and transference number with 30 wt% addition of PAA reach up to 1.66 and 0.58 mS/cm, respectively. After 500 cycling at 0.5 C, the discharge specific capacity and the capacity retention rate are still up to 134.1 mAh/g and 88.7%, respectively. This research proves the great possibility of applying environmentally friendly method, low cost, and high electrochemical performances of PEO/PAA based GPEs in the lithium batteries.     

Self-assembly of thiourea intercalated graphene oxide based dual IIP for the SPE coupled FAAS method development of Cu(II) and Pb(II) determination

A new dual-template surface imprinted polymer for Cu(II) and Pb(II) was synthesized in one pot. Magnetic graphene oxide was self-assembled with low cost and environmentally benign thiourea. Presence of sulfur and nitrogen donor atoms provide hooks for coordination and partial reduction of graphene oxide matrix. It was used as an solid-phase extraction adsorbent for extraction, preconcentration, and coupled with flame atomic absorption spectrometry to manifest performance comparable with inductively coupled plasma atomic emission spectrometry (ICPAES) both in terms of quantification limit as well as interference. The critical experimental parameters such as pH; 4.6, contact time of 15 min and initial concentration of 777 (Q_e; 227 mg g⁻¹) and 800 μg L⁻¹ (Q_e; 273 mg g⁻¹) for Cu(II) and Pb(II), respectively, were optimized using RSM-CCD and artificial neural network. The adsorption process was kinetically faster (50% adsorption in 5 min), following fractal-like-pseudo-second-order (FLPSO) kinetics and Brouers–Sotolongo isotherm model owing to the heterogenous energy landscape. The imprinting factors were in the range of 4–7 in the presence of all coexisting ions. The proposed method was robust in the determination and removal of Cu(II) and Pb(II) from food, ground water, and industry effluents with low limit of detection (Cu(II); 1.03 μg L⁻¹ & Pb(II); 1.79 μgL⁻¹). Spiking and recovery tests were used to assess the method's accuracy. Cu(II)/Pb(II) loaded dual template IIP (DIIP) was utilized to remove anionic dyes with >95% efficiency. Thorough examination of the method and material selectivity (in binary, ternary, and multielement system), multi fold applications of determination, removal of Cu(II), Pb(II), and removal of anionic dyes makes DIIP a promising candidate for environmental remediation.     

树枝状侧基型聚合物的合成及其溶液性质

以乙二胺、丙烯酸甲酯、丙烯酰胺为原料,通过丙烯酰胺及丙烯酸甲酯自由基聚合反应合成聚合物主链,主链酯基为侧基反应中心,利用乙二胺与丙烯酸甲酯交替发生的酰胺化反应以及Michael加成反应合成树枝状侧基,制备了一种新型树枝状侧基型聚合物,并利用红外光谱(FTIR)、凝胶色谱(GPC)、扫描电镜(SEM)进行表征。最佳合成条件:反应温度30℃,反应时间24～48 h,反应物摩尔比1∶1。对合成聚合物的水溶液性质进行了评价,增黏能力较改性前提高了3倍;高温、高矿化度下黏度保持率较改性前分别提高了50%与80%,表现出良好的抗温抗盐性,达到了分子结构设计的预期效果。