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基于动态硼酸酯键构筑的聚合物有一定的自修复能力和对刺激的多重响应性,能够通过诱导材料内部物理/化学结构的拓扑重组并以此来响应生物信号的变化。本文综述了基于水解/再酯化、二醇硼酸酯之间的酯交换和硼酸酯之间的酯交换3种不同的硼酸酯酯交换机制构筑的多种天然/非天然高分子材料;通过传统共价键和硼酸酯动态共价键协同作用设计更加稳定的四面体硼酸盐结构来解决硼酸酯基聚合物稳定性较差的策略;硼酸酯基聚合物在生物医药、传感器和可回收材料等多领域的应用潜力。重点介绍了硼酸酯键与其它动态键协同作用制备理想的聚合物材料,如水凝胶、有机凝胶、液晶材料和可回收纳米材料等。 相似文献
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利用巯基与环氧的点击反应,向环氧体系中引入二醇结构,并通过硼酸酯键对其进行交联,制备了一系列不同流变性能和玻璃化转变温度的可塑环氧树脂材料。研究了不同的配方对材料性能的影响,结果表明通过改变交联剂与动态链结的比例,体系的流变性能可以被调控;另一方面,改变软硬环氧组分的比例可以使材料的玻璃化转变温度在14.6~36.5℃之间调节。制备了该可塑环氧树脂与密胺通孔泡沫的复合材料,该材料具备良好的快速自黏结性能。材料断裂后,在10 s内即可达到最大黏结强度,且经多次拆卸-黏结循环后,黏结强度可以保持在约0.06 MPa。 相似文献
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硼酸酯类键合剂研究进展 总被引:2,自引:0,他引:2
介绍硼酸酯类键合剂的发展现状,分析硼酸酯类键合剂在固体推进剂中的作用机理及其在应用中存在的问题,总结了几种典型的合成方法,对其优缺点进行了对比,并就该类键合剂的研究方向提出一些建议。 相似文献
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通过4-(溴甲基)苯基硼酸(PBA)和1-乙烯基咪唑(IL)的烷基化反应制备了苯硼酸离子液体(PBA-IL)单体。在2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)氧化纳米纤维素(CNF)的存在下,通过丙烯酰胺(AM)和PBA-IL的一步聚合反应,制备了一种具有半互穿网络结构的自修复导电水凝胶(PAM/PBA-IL/CNF)。通过1HNMR对PBA-IL的化学结构进行表征;通过FTIR、XPS、SEM对水凝胶的化学结构和物理形貌进行表征,并测试了水凝胶的拉伸性能、自修复性能和导电性能。结果表明,PBA-IL单体和水凝胶成功制备,且水凝胶具有典型的多孔结构。PAM/PBA-IL3/CNF水凝胶[3代表PBA-IL含量为30%,以AM、PBA-IL、CNF悬浮液、N,N’-亚甲基双丙烯酰胺(MBA)溶液、过硫酸铵(APS)的总绝干质量为基准]的断裂应力为335.1 kPa、断裂伸长率为1969.5%、断裂能为12.1 kJ/m2、自修复效率为95.43%(150 min)、电导率为6.38 mS/cm。 相似文献
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由于肿瘤细胞的高代谢率导致供氧不足,肿瘤细胞在低灌注区的细胞外间隙与周围正常组织细胞相比具有高酸性,因此具有pH敏感性的纳米载药系统被广泛应用于癌症治疗中。硼酸酯键是一种可逆的pH敏感性的化学键,在酸性环境中此键可以断裂,将其制备成具有pH响应性硼酸酯键的纳米载药系统,可以达到pH敏感性控制释放药物的目的。 相似文献
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以丙烯酸(AA)、丙烯酰胺(AM)为单体对黄原胶(XG)进行接枝改性,再以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,过硫酸铵(APS)为引发剂,加入凹凸棒黏土,采用溶液聚合法合成了一种新型复合高吸水性树脂。通过单因素试验研究了AA中和度、交联剂用量、引发剂用量、反应温度和凹凸棒黏土用量等因素对该树脂吸水(吸盐水)性能的影响,利用傅里叶红外光谱(FT-IR)仪、热重分析(TGA)仪对其结构和热性能进行了表征。结果表明:制备高吸水性树脂的最佳工艺条件为AA中和度70%,反应温度70℃,w(交联剂)=0.06%,w(APS)=1.0%,w(凹凸棒黏土)=5%;在最佳工艺条件下制备的高吸水性树脂,其最大吸水倍率、吸盐水倍率分别为827、109 g/g。 相似文献
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J. L. Pérez-Salas M. R. Moreno-Jiménez N. E. Rocha-Guzmán W. Rosas-Flores R. F. González-Laredo L. Medina-Torres J. A. Gallegos-Infante 《Journal of the American Oil Chemists' Society》2023,100(9):699-709
As biphasic systems bigels are formed by hydrogels and organogels. Given their characteristics, they have been studied in food, pharmaceutical and cosmetic applications for bioactives delivery. The rheological characteristics and amount used of the individual structured systems influence the final properties; thus, the objective of this work was to evaluate the effect of the proportion of castor oil organogel, the concentration of organogelator, and the storage time in the mechanical and microstructural properties of bigeles. Bigels were prepared from structured castor oil organogels with monoacylglycerides at concentrations of 6% (MOG) and 6.5% (HOG) wt/wt, and hydrogels with 2% wt/wt xanthan gum (HG) at three organogel/hydrogel ratios 15 of 85, 30 of 70, and 45 of 55. Bigels were characterized by optical microscopy with polarized light filter, centrifugal stability, texture, and rheology for 60 days. The increase in the proportion of organogel favors the mechanical response (k, G0, and firmness) of bigels. The high viscosity of castor oil slows down the structuring of organogel droplets, showing an improvement in its mechanical properties after 15 days of its preparation. The increase in the organogelator concentration is significant in the bigels with 30% and 45% proportions of organogel in the rheological tests. By using HOG in the formation of bigels, higher values for G0 and k were obtained, as well as higher centrifugal stability compared with bigels formed from MOG. The rheological and microstructural behavior of bigels can be modified according to their application by varying the proportions of organogel/hydrogel and the concentration of the organogelator. 相似文献
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Maria de Morais Lima Daniela Bianchini Alvaro Guerra Dias Elessandra da Rosa Zavareze Carlos Prentice Angelita da Silveira Moreira 《应用聚合物科学杂志》2017,134(23)
The aim of this study was to develop films based on chitosan, xanthan gum, and protein hydrolysate of Whitemouth croaker (Micropogonias furnieri), evaluating their antioxidant activity and also their mechanical, physical, structural, morphological, thermal, and barrier properties. The mixture of xanthan gum and protein hydrolysate promoted some changes in chitosan films. The addition of xanthan gum increased tensile strength and changed the color parameters of films. The addition of Whitemouth croaker protein hydrolysate increased the antioxidant activity of the films. However, higher concentrations of hydrolysate tend to increase moisture and decrease their tensile strength. All films had homogeneous structure, with no phase separation and fissures. Significant differences in water solubility and water vapor permeability were not observed by the addition of xanthan gum and protein hydrolysate. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44899. 相似文献
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Rasoul Niknam Mohammad Reza Soudi Mohammad Mousavi 《Journal of the American Oil Chemists' Society》2023,100(2):163-174
Nowadays, preparing biodegradable films based on hydrocolloids has become thoroughly crucial in food packaging. Also, to enhance some of the aspects of these films, adding oil to the formulation of the films has been considered as a valid method. In this study, a variety of films based on two biopolymers (fenugreek galactomannan and xanthan gum) in the presence or absence of grape seed oil were produced and the various aspects of the obtained films were comprehensively investigated. The obtained data demonstrated that preparing composite films based on two hydrocolloids improved the aspects including film thickness, water vapor permeability (WVP), oxygen permeability (OP), mechanical and thermal properties more than films based on only one hydrocolloid. This improvement was mostly related to the good and acceptable interaction between two biopolymers. The X-ray diffraction (XRD) patterns indicated that all films had an amorphous or non-crystalline structure. Also, the scanning electron microscope images demonstrated that films based on fenugreek galactomannan and composite films based on two hydrocolloids. The value of film thickness and strain at break (SAB) increased by adding oil to the formulation. Contrarily, the moisture content and absorption, WVP, OP, opacity, and ultimate tensile strength (UTS) values of the films decreased by adding oil. 相似文献
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黄原胶与丙烯酰胺接枝共聚反应的研究 总被引:1,自引:0,他引:1
以过硫酸铵为引发剂,在氮气保护下,研究了黄原胶与丙烯酰胺的接枝共聚反应。考察了单体浓度、引发剂浓度、反应温度和反应时间等因素对接枝率及接枝效率的影响,探讨了过硫酸铵引发黄原胶接枝丙烯酰胺共聚反应的基本规律。采用红外光谱、X射线粉末衍射对接枝共聚物的结构进行研究,用热重分析法表征了产物的热性能,并初步探讨了接枝机理。结果表明,过硫酸铵能有效地引发黄原胶与丙烯酰胺的接枝共聚反应,并且接枝率和接枝效率随单体浓度、引发剂浓度、反应温度的变化出现极大值,随反应时间的延长不断上升,直至基本不变。 相似文献
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含硫、氮的硼酸酯添加剂的制备及摩擦学性能 总被引:1,自引:0,他引:1
在催化剂存在下,通过酯化反应制备了含二正丁基二硫代氨基甲酸结构的有机硼酸酯(SNBC)。通过四球磨损试验机考察SNBC在100N基础油中的摩擦学性能,采用扫描电子显微镜(SEM)和能谱仪(EDS)分别分析磨损表面形貌和磨斑表面元素组成,通过水解稳定性实验测定硼酸酯的水解稳定性。结果表明,合成的硼酸酯(SNBC)具有较好的水解稳定性,同时SNBC作为润滑油添加剂与二烷基二硫代磷酸锌(ZDDP)相比具有较好的减摩性能,在低添加量下能显著提高基础油的极压性能。SEM分析表明,SNBC能有效减轻钢球摩擦副表面的擦伤和磨损。 相似文献
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C. L. Mott N. S. Hettiarachchy M. Qi 《Journal of the American Oil Chemists' Society》1999,76(11):1383-1386
The foaming properties of whey protein isolate (WPI) in the presence of xanthan gum (XG) were investigated. XG dispersion
did not exhibit any foaming properties. The optimal foaming overrun (FO), or the amount of air incorporated into the dispersion,
was obtained from the dispersion of 5% WPI and 0.05% XG at 949%. This WPI-XG dispersion had a significantly higher overrun
than that of WPI (868%) or egg white (879%) (P<0.05). Optimal foam stability (FS) of 216 min was obtained at 5% WPI and 0.2% XG; however, the overrun was reduced slightly
(844%). XG increased stability to 15 times that of WPI alone. The overrun of 5% WPI plus 0.05% XG was further increased to
1343% when 1 M NaCl was added (P<0.05). However, FS (51 min) was significantly reduced. A significant increase in the FO of 5% WPI plus 0.05% XG (1081%) was
observed when pH was adjusted to 5.0 with no significant change in FS (56 min) (P<0.05). The FO (1457%) was significantly increased (P<0.05) when the WPI-XG was heat treated (55°C for 5 min). WPI-XG dispersions at acidic pH and temperatures below 85°C have
a variety of potential applications in products such as protein beverages, angel food cake, and unique infant formulas. 相似文献