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ZnO-石墨烯-TPU/PLA复合材料的制备及吸波性能

吴海华, 傅文鑫, 刘少康, 晁彬, 鲍云天

吴海华, 傅文鑫, 刘少康, 等. ZnO-石墨烯-TPU/PLA复合材料的制备及吸波性能[J]. 复合材料学报, 2024, 41(3): 1316-1326. DOI: 10.13801/j.cnki.fhclxb.20230627.003
引用本文: 吴海华, 傅文鑫, 刘少康, 等. ZnO-石墨烯-TPU/PLA复合材料的制备及吸波性能[J]. 复合材料学报, 2024, 41(3): 1316-1326. DOI: 10.13801/j.cnki.fhclxb.20230627.003
WU Haihua, FU Wenxin, LIU Shaokang, et al. Study on preparation and absorption properties of ZnO-graphene-TPU/PLA composites[J]. Acta Materiae Compositae Sinica, 2024, 41(3): 1316-1326. DOI: 10.13801/j.cnki.fhclxb.20230627.003
Citation: WU Haihua, FU Wenxin, LIU Shaokang, et al. Study on preparation and absorption properties of ZnO-graphene-TPU/PLA composites[J]. Acta Materiae Compositae Sinica, 2024, 41(3): 1316-1326. DOI: 10.13801/j.cnki.fhclxb.20230627.003

ZnO-石墨烯-TPU/PLA复合材料的制备及吸波性能

基金项目: 国家自然科学基金 (51575313)
详细信息
    通讯作者:

    吴海华,博士,教授,博士生导师,研究方向为3D打印吸波材料及其工程应用技术 E-mail: wuhaihua@ctgu.edu.cn

  • 中图分类号: TB333

Study on preparation and absorption properties of ZnO-graphene-TPU/PLA composites

Funds: National Natural Science Foundation of China (51575313)
  • 摘要: 开发轻质、高效的吸波复合材料是解决电磁污染问题的重要途径之一。本文采用两步法制备ZnO-石墨烯-热塑性聚氨酯弹性体橡胶 (TPU)/聚乳酸 (PLA)吸波复合材料,通过XRD、拉曼光谱、SEM和矢量网络分析仪分别对复合材料的物相结构、微观形貌和电磁特性进行表征,并研究不同ZnO/石墨烯吸波剂组合对复合材料吸波性能的影响,揭示ZnO和石墨烯协同吸波机制。研究结果表明:随着ZnO含量的增加,吸波效果先增强后减弱。适量的ZnO分散在基体中,使复合材料的缺陷程度增加,这丰富了异质界面,增强了界面极化和偶极极化,进而改善了复合材料的吸波性能。当ZnO添加量仅为2wt%时吸波效果最佳,在5.6 mm厚度下,其最小反射损耗为−49.2 dB,有效吸收带宽为2.0 GHz。优异的吸波效果源于良好的阻抗匹配和界面极化损耗、偶极极化损耗、电导损耗之间的协同作用。此外相比化学法制备的吸波材料,ZnO-石墨烯-TPU/PLA复合材料的制备过程简单环保,吸波剂组分可调,轻质高效可规模化生产,有望用于复杂吸波结构制造。

     

    Abstract: Developing light-weight and high-efficiency absorbing composite materials is one of the important ways to solve the electromagnetic pollution. In this paper, ZnO-graphene (GR)/polylactic acid (PLA)/thermoplastic polyurethane (TPU) composite materials were prepared by a two-step method and the phase structure, micromorphology and electromagnetic characteristics of the composite were characterized by XRD, Raman spectroscopy, SEM and vector network analyzer. The effects of different combinations of ZnO/GR on the microwave absorbing properties of the composites were studied, and the synergistic mechanism was revealed. The results show that with the increase of the content of ZnO, the microwave absorbing effect increases at first and then decreases. Proper amount of ZnO dispersed in the matrix increases the defects of the composites enriching the heterogeneous interface, enhancing the interface polarization and dipolarization, and improving the microwave absorbing properties of the composites. When the content of ZnO is 2wt% , at 5.6 mm thickness, the minimum reflection loss is −49.2 dB and the effective absorption bandwidth is 2.0 GHz meaning the best absorption efficiency. The excellent absorbing effect is attributed to the good impedance matching and the synergy among the interface polarization loss, the dipolarization loss and the conductivity loss. In addition, the preparation process of ZnO-GR/PLA/TPU composite is simple and environment-friendly, and the component of absorbing agent can be adjusted which is expected to be used in the manufacturing of complex absorption structures.

     

  • 近年来,随着经济的快速发展,工业化污染严重导致各类细菌滋生和传播,由细菌感染引发的伤口感染、人体炎症、伤寒等症状一直威胁着人类健康[1]。致病性细菌感染可通过飞沫、接触及气溶胶进行快速传播,存在很大的感染风险。目前,由革兰氏菌引起的传染病是全球几大健康问题之一[2-3],但使用抗生素治疗细菌感染存在诸多不足,例如,细菌耐药性及多药外排泵作用等[4-5]。为克服细菌耐药性等缺点,多种新型抑菌材料不断被开发出来,但多数材料的抑菌效果不佳[6],某些材料还需要复杂的表面改性才能实现抑菌功能[7-8],因此,开发高性能的抑菌材料并研究其抑菌机制,解决细菌耐药性具有重要的应用价值。通过研究发现,金属有机骨架材料与细菌之间可通过范德华力、静电相互作用导致细菌死亡,也不会使细菌基因发生突变而产生耐药性,表现出良好的抑菌性能[9]

    金属-有机骨架(Metal-organic framework,MOF)是由金属离子或离子簇与有机配体配位组成的多孔纳米材料[10],在吸附分离[11]、气体储存[12]、药物分子输送[13]和化学催化[14]等方面备受青睐。通过有机配体与作为节点的金属离子或离子簇配位,MOF材料可以制备具有预期的结构,并实现其结构的功能化,同时也因其缓慢的释放能力、高比表面积和大孔隙率等优势逐渐成为一种新的载体[15]。近年来,基于MOF结构为载体的材料已经成为抑菌应用的一个热点[16-19]。UiO-66-NH2是以Zr6O4(OH)4簇为金属节点,2-氨基对苯二甲酸为配体,形成的具有三维立体骨架八面体结构的材料[20-23]。UiO-66-NH2材料不仅具有低毒性、高耐水性和良好的结构稳定性[24],而且结构中的氨基可以作为反应位点进一步功能化[25],因此可以将UiO-66-NH2材料作为理想的载体,进一步功能化改性后,用于抗菌方面的研究。

    基于此,本文通过水热法合成了锆基MOF材料UiO-66-NH2,将多孔UiO-66-NH2作为可再生载体,以亚氯酸钠为活性氯来源,通过后合成改性的方法,使活性氯原子与骨架中的氨基官能团形成一种氯胺基团,合成了UiO-66-NHCl新型复合抑菌材料,采用XRD、FTIR、SEM、TEM、EDS和XPS等手段对UiO-66-NHCl复合材料进行表征,同时探索了不同负载工艺对氯负载量的影响,并研究了UiO-66-NHCl复合材料的抑菌性能。结果显示,UiO-66-NHCl对革兰氏阳性菌和革兰氏阴性菌的广谱灭活具有快速而有效的作用,在抑菌方面表现出优异的性能。

    四氯化锆(ZrCl4)、2-氨基-1, 4-苯二甲酸(NH2-BDC)、亚氯酸钠,上海麦克林生化科技有限公司;碘化钾,天津市科密欧化学试剂有限公司;硫代硫酸钠、淀粉、N, N-二甲基甲酰胺(DMF)、无水甲醇,天津市永大化学试剂有限公司;重铬酸钾,莱阳市康德化工有限公司;大肠杆菌、金黄色葡萄球菌,北京生物保藏生物科技有限公司;蛋白胨、牛肉膏、琼脂粉,天津市英博生化试剂有限公司。

    将ZrCl4 (4.5 mmol)和NH2-BDC (6.4 mmol)溶于DMF (40 mL),超声搅拌20 min,随后将冰醋酸(HAc,0.3 mmol)加到上述悬浮液,继续超声搅拌20 min。将搅拌后的悬浮液转移到不锈钢高压釜(100 mL),在135℃下反应24 h。将产物冷却至室温,再用DMF和无水甲醇洗涤离心数次,最后将产物在80℃真空干燥8 h。

    将一定质量的UiO-66-NH2材料,置于亚氯酸钠溶液(pH=5)中,避光搅拌4 h,抽滤,收集固体产物,产物用无水乙醇洗涤3次,以去除氯化后材料表面的杂质,产物在40℃下真空干燥12 h,得到UiO-66-NHCl复合材料。在保证其他条件不变的情况下,采用单一因素法设置不同氯负载比例(质量比m(UiO-66-NH2)∶m(NaClO2))和氯化时间(0.5 h、2 h、4 h、6 h),浸渍抽滤后,滤液用碘量滴定法测定有效氯的含量。氯负载量的计算公式如下所示:

    =m0mfmads×100% (1)

    式中:m0为初始亚氯酸钠的质量(g);mf为上清液中亚氯酸钠的质量(g);mads为UiO-66-NH2的质量(g)。

    采用亚氯酸钠溶液浸渍改性合成了UiO-66-NHCl新型复合抑菌材料,通过碘钾氧化实验验证UiO-66-NHCl复合材料中活性氯的存在,用滴定法加入硫代硫酸钠溶液滴定来计算氯的含量。有效氯含量计算公式如下所示:

    Cl(%)=CV×35.45×100W×2 (2)

    式中:C为硫代硫酸钠滴定液浓度(0.01 mol/L);V为消耗硫代硫酸钠滴定液体积(mL);W为MOF复合材料的质量(g)。

    在储存过程中,氯的释放会降低材料的杀菌效果,因此探究UiO-66-NHCl复合材料在高温、高湿和强光等条件下密封储存30天后的稳定性,通过碘量滴定法测UiO-66-NHCl复合材料中活性氯的含量,通过抑菌实验直观表现UiO-66-NHCl的杀菌效果。

    高温实验是设定条件温度为60℃,每5 天取样,测量30天内UiO-66-NHCl材料中活性氯的含量。高湿和强光实验分别设定条件温度为25℃,湿度为75%;光照强度为4500 lx,其他步骤同上。

    根据《消毒技术规范》(2002年版)[26]配制Luria-Bertani (LB)液体培养基、LB固体培养基和相应的菌悬液。采用抑菌圈法对UiO-66-NHCl的抑菌性能进行评价。配制不同浓度的UiO-66-NHCl复合材料,将菌悬液均匀涂布在含有培养基的平板上。用移液枪吸取20 μL不同浓度的样品,滴加到灭菌后滤纸片的表面,对照滤纸片滴加20 μL浓度为0.9%的生理盐水,将平板倒置在37℃电热恒温培养箱(DPH 9402,上海一恒科学仪器有限公司)培养12~16 h后,观察结果,记录抑菌圈直径的大小。

    根据《消毒技术规范》(2002年版)[26]对选用的新西兰兔进行完整和破损皮肤刺激性实验,采用同体左右侧自身对比法,即每只新西兰兔左侧去毛区域涂抹生理盐水做对照,右侧去毛区域涂抹UiO-66-NHCl抑菌材料。给药4 h后清洁,每天对新西兰兔给药1次,连续给药7天。观察新西兰兔是否正常,并记录是否出现红斑和水肿情况。表1为皮肤刺激性反应评分标准。

    表  1  皮肤刺激性反应评分标准
    Table  1.  Skin irritation response scoring criteria
    ErythemaScoreEdemaScore
    No0No0
    Mildly (barely visible)1Mildly (barely visible)1
    Moderately (clearly visible)2Moderately (visible bulge)2
    Severely3Severely (skin augmentation of 1 mm, clear contours)3
    下载: 导出CSV 
    | 显示表格

    采用浸渍键合的方法合成UiO-66-NHCl材料,探究不同的氯负载比例与氯化时间对UiO-66-NHCl材料合成的影响,并计算氯负载量。如表2所示,在氯负载比例为1∶5时,氯负载量最高,氯负载比例为1∶9时次之。图1(a)为不同氯负载比例的UiO-66-NHCl的XRD图谱(D/MAX-2500 型X 射线衍射仪,日本Rigaku公司),可知,1-3组材料的XRD图谱与模拟的UiO-66-NH2的XRD图谱基本一致,说明UiO-66-NHCl的晶体结构并未发生改变,而当氯负载比例为1∶9 (4组)时,其XRD图谱中并未出现材料的特征峰,表明材料未成功合成。选取氯负载比例为1∶5的条件下对氯化时间进行探究,当氯化时间为4 h时,材料的氯负载量最高,且随着氯化时间的增加,材料的结晶度下降,如图1(b)所示。

    表  2  活性氯负载比例与氯化时间对氯负载量的影响
    Table  2.  Effect of active chlorine loading ratio and chlorination time on chlorine loading
    No.Chlorine
    load ratio
    Chlorination
    time/h
    Chlorine
    loading/wt%
    11∶346.65
    21∶549.35
    31∶747.12
    41∶949.04
    51∶50.54.85
    61∶528.40
    71∶549.11
    81∶568.54
    下载: 导出CSV 
    | 显示表格

    采用S-4800-I 型场发射扫描电子显微镜(日本HITACHI 公司)对不同氯负载比例和氯化时间所制备材料进行形貌分析,其SEM图像如图2所示,氯负载比例在1∶7范围内,材料均表现为均匀的颗粒,呈现出八面体结构,氯负载比例在1∶9时,材料发生团聚,结晶度低,此时八面体结构已被破坏,这点可以从图1(a)样品的XRD图谱中看出;而随着氯化时间的增加,材料逐渐开始团聚,但颗粒形态仍保持八面体结构。

    图  1  UiO-66-NH2和UiO-66-NHCl的XRD图谱:(a) 不同氯负载比例;(b) 不同氯化时间
    Figure  1.  XRD patterns of UiO-66-NH2和UiO-66-NHCl: (a) Different chlorine loading ratios; (b) Different chlorination time
    图  2  UiO-66-NH2/NaClO2的SEM图像:((a)~(d)) 负载比例分别为1∶3、1∶5、1∶7、1∶9;((e)~(h)) 氯化时间分别为0.5 h、2 h、4 h、6 h
    Figure  2.  SEM images of UiO-66-NH2/NaClO2: ((a)-(d)) Loading ratios of 1∶3, 1∶5, 1∶7, 1∶9; ((e)-(h)) Chlorination time of 0.5 h, 2 h, 4 h, 6 h, respectively

    通过碘量滴定法测定UiO-66-NHCl中有效氯的含量。从图3中(左)可以看出,未经氯化处理的 UiO-66-NH2材料在加入碘化钾溶液后,溶液没有发生任何颜色变化,而将UiO-66-NH-Cl复合材料与碘化钾溶液混合后,清澈的无色溶液立即变成棕色,这是由于溶液中碘离子被活性氯胺(N—Cl)氧化,碘被释放出来,颜色变为棕色,证明所制备的UiO-66-NHCl复合材料中含有N—Cl结构。反应式如式(3)所示。

    图  3  UiO-66-NH2加KI溶液(左);UiO-66-NHCl加KI溶液(中);UiO-66-NHCl加KI溶液后滴定(右)
    Figure  3.  KI solution added to UiO-66-NH2 (left); KI solution added to UiO-66-NHCl (middle); KI solution added to UiO-66-NHCl after titration (right)
    NCl+2I+H+NH+I2+Cl (3)
    I2+2S2O232I+S4O26 (4)

    通过碘量滴定法测定UiO-66-NHCl中有效氯的含量,从图3中(右)可以看出,滴定硫代硫酸钠溶液后,颜色由棕色变为无色,这是由于所生成的碘单质与硫代硫酸根离子反应,再变为碘离子,反应式如式(4)所示。

    图4为UiO-66-NH2和UiO-66-NHCl的XRD图谱,可见,在2θ=7.4°、8.5°、25.7°等处出现的衍射峰,与模拟UiO-66-NH2的出峰位置相吻合,表明成功合成了UiO-66-NH2[27];同时,UiO-66-NHCl的衍射峰和UiO-66-NH2的基本保持一致,表明UiO-66-NH2的晶体结构在引入活性氯后未发生变化,结构保持较好。

    图  4  UiO-66-NH2和UiO-66-NHCl的XRD图谱
    Figure  4.  XRD patterns of UiO-66-NH2 and UiO-66-NHCl

    采用FTS-65A1896型傅里叶红外光谱(美国铂金埃尔默公司)对UiO-66-NH2和UiO-66-NHCl进行红外光谱分析,如图5所示。在660~680 cm−1和460~480 cm−1处分别为μ3—O和μ3—OH基团的拉伸振动[28],UiO-66-NH2存在553 cm−1处的峰对应Zr—(OC)的不对称拉伸振动,1610~1550 cm−1和1420~1335 cm−1分别对应有机配体中O—C—O的对称和不对称伸缩振动。此外,1255 cm−1处表现为芳香胺特有的C—N键拉伸振动,1507 cm−1处的峰是由H2-BDC中C=C键振动引起的,而1661 cm−1处的峰是由于材料孔内残余的DMF或丙酮的C=O键的拉伸振动。在3270 cm−1和3309 cm−1处为—NH2官能团特有的伯胺基团的双吸收峰,表明UiO-66-NH2材料成功合成[29]。UiO-66-NHCl复合材料红外图谱显示,负载活性氯后,在3290 cm−1处出现仲胺基团的单峰,原始材料的氨基官能团的双峰消失[30],表明UiO-66-NH2材料氨基上的氢已成功被活性氯取代,成功制备出UiO-66-NHCl复合材料。

    图  5  UiO-66-NH2和UiO-66-NHCl的FTIR图谱
    Figure  5.  FTIR spectra of UiO-66-NH2 and UiO-66-NHCl

    (1) 微观形貌分析

    原始UiO-66-NH2材料的SEM图像如图6(a)~6(c)所示,可以看出所合成的UiO-66-NH2呈规则的八面体结构,这与文献[31]中所制备材料的形貌相符,表明材料成功合成,且UiO-66-NH2材料粒径大小较均一,粒径大约为300 nm。而通过活性氯改性的UiO-66-NHCl材料在负载活性氯后,材料的形貌没有发生太大变化,说明经活性氯改性后,不会影响UiO-66-NH2的结构(图6(d)~6(f))。采用JEM-2100型透射电子显微镜(德国电子有限公司)对UiO-66-NH2和UiO-66-NHCl进行形貌分析,其TEM图像如图7所示,所制备的UiO-66-NH2内部为实心结构,且在经活性氯改性后,UiO-66-NHCl材料的内部结构状态没有发生改变,表明氯的掺杂没有影响材料的晶体结构。

    图  6  UiO-66-NH2 ((a)~(c))和UiO-66-NHCl ((d)~(f))的SEM图像
    Figure  6.  SEM images of UiO-66-NH2 ((a)-(c)) and UiO-66-NHCl ((d)-(f))
    图  7  UiO-66-NH2 ((a)~(c))和UiO-66-NHCl ((d)~(f))的TEM图像
    Figure  7.  TEM images of UiO-66-NH2 ((a)-(c)) and UiO-66-NHCl ((d)-(f))

    (2)元素含量分析

    采用S-4800-I型X 射线能谱仪(日本HITACHI公司)对UiO-66-NH2和 UiO-66-NHCl进行元素分析,如图8所示,原始UiO-66-NH2材料含有C、N、O、Zr元素,表明材料已成功合成;经活性氯改性后,UiO-66-NHCl材料上有Cl元素的存在,进一步证明了活性氯已成功的被引入到UiO-66-NHCl材料中。

    (3) 元素价态分析

    图  8  UiO-66-NH2和UiO-66-NHCl的EDS元素分析((a), (b));UiO-66-NHCl的元素分布图像((c)~(f))
    Figure  8.  EDS elemental analysis of UiO-66-NH2 and UiO-66-NHCl ((a), (b)); Elemental distribution images of UiO-66-NHCl ((c)-(f))

    通过X射线光电子能谱仪(ESCALAB 250Xi,赛默飞世尔科技有限公司)分析UiO-66-NHCl中各个元素的元素组成和化学状态。图9(a)为UiO-66-NH2和UiO-66-NHCl的XPS总光谱对比图,可以看出,氯化后,在200 eV左右出现了明显的属于Cl元素的峰,399.8 eV处也出现了N元素的峰,表明Cl成功被引入到UiO-66-NH2中,与C、O和Zr元素的峰相比,Cl元素的峰较弱,也说明Cl的含量明显低于其他元素,这与EDS结果一致。在C1s图谱中(图9(b)):284.1、285.5和288.04 eV处的峰分别对应于:C—C键、C—O键和OH—C=O键,这些键归属于H2-BDC。O1图谱(图9(c))可分为3个峰:530.1 eV处的峰为Zr—O键,531.3 eV处的峰为表面活性氧物种C=O,而在532.6 eV处的峰可归因于H—O的化学吸附氧物种。如图9(d)所示,可以观察到Zr3d5/2和Zr3d3/2结合能的峰归属于Zr—O键,表明锆氧簇中Zr4+的存在[32]。在N1s高分辨图谱中(图9(e)),398.2、399.8和400.8 eV处的3个峰分别对应于吡啶氮、吡咯氮和石墨氮[33]。对Cl2p图谱(图9(f))分析,发现了Cl2p3/2 (199.8 eV)和Cl2p1/2(201.3 eV)的自旋-轨道分裂双态,这可能与N—Cl键的存在有很大的关系[34]

    图  9  (a) UiO-66-NH2和UiO-66-NHCl的XPS全谱图;(b) C1s;(c) O1s;(d) Zr3d;(e) N1s;(f) Cl2p
    Figure  9.  (a) Total XPS spectra of UiO-66-NH2 and UiO-66-NHCl; (b) C1s; (c) O1s; (d) Zr3d; (e) N1s; (f) Cl2p

    由于储存过程中氯的释放会降低材料的抑菌效果,因此研究了UiO-66-NHCl复合材料在高温、高湿和强光等条件下的稳定性。如图10所示,在高温60℃、高湿75%和强光4500 lx的因素下,30天后,测定了材料所负载的活性氯含量分别为原始氯负载量的82%、89.3%和81.2%。因此,UiO-66-NHCl复合材料在高温、高湿和强光条件下仍能保持较好的稳定性。表3为UiO-66-NHCl复合材料对金黄色葡萄球菌和大肠杆菌的抑菌圈直径。图11图12分别为UiO-66-NHCl复合材料对金黄色葡萄球菌和大肠杆菌的抑菌效果图。可以看出,随着稳定性实验天数的增加,抑菌圈直径虽在减小,但仍大于7 mm,表明在经过高温、高湿和强光实验后,材料仍能保持较好的抑菌效果。

    图  10  UiO-66-NHCl在不同条件下的稳定性实验结果
    Figure  10.  Experimental results on the stability of UiO-66-NHCl under different conditions
    表  3  UiO-66-NHCl复合材料在高温、高湿和强光条件下的抑菌圈直径的影响(标准差,±SD mm)
    Table  3.  Effect of UiO-66-NHCl composites on the diameter of the inhibition circle under high temperature, high humidity and strong light conditions (Standard deviation, ±SD mm)
    StrainsFactorsDiameter/mm
    0 d5 d10 d15 d20 d25 d30 d
    Staphylococcus aureusHigh temperature10.12±0.319.57±0.299.13±0.378.76±0.348.04±0.417.69±0.297.25±0.38
    High humidity10.33±0.289.88±0.349.32±0.148.94±0.258.25±0.187.91±0.437.63±0.36
    Bright light10.14±0.199.62±0.169.17±0.218.82±0.328.15±0.287.83±0.377.33±0.45
    Escherichia coliHigh temperature10.07±0.279.61±0.379.05±0.358.62±0.288.01±0.327.52±0.477.16±0.39
    High humidity10.21±0.249.82±0.299.14±0.368.77±0.358.19±0.277.74±0.427.33±0.32
    Bright light10.11±0.329.67±0.269.09±0.428.53±0.298.08±0.367.67±0.517.25±0.43
    下载: 导出CSV 
    | 显示表格
    图  11  UiO-66-NHCl复合材料对金黄色葡萄球菌的抑菌效果
    Figure  11.  Bacterial inhibition effect of UiO-66-NHCl composite against Staphylococcus aureus
    图  12  UiO-66-NHCl复合材料对大肠杆菌的抑菌效果
    Figure  12.  Bacterial inhibition effect of UiO-66-NHCl composites on Escherichia coli

    图13图14为不同浓度下UiO-66-NH2材料改性前后对革兰氏阳性菌(金黄色葡萄球菌)和革兰氏阴性菌(大肠杆菌)的抑菌结果,表4为不同浓度下,UiO-66-NH2和UiO-66-NHCl对金黄色葡萄球菌和大肠杆菌抑菌圈直径。可以看出,氯化后的UiO-66-NHCl复合材料对金黄色葡萄球菌和大肠杆菌均有抑制作用;随着样品浓度的增加,抑菌圈直径也随之增加,抑菌作用也随之增强。相比之下,未氯化的UiO-66-NH2材料抑菌圈直径为0,没有表现出抑菌效果。

    图  13  UiO-66-NH2材料改性前后对金黄色葡萄球菌的抑菌结果影响
    Figure  13.  Effect of inhibition results of UiO-66-NH2 material on Staphylococcus aureus before and after modification
    图  14  UiO-66-NH2材料改性前后对大肠杆菌的抑菌结果影响
    Figure  14.  Effect of inhibition results of UiO-66-NH2 material on Escherichia coli before and after modification
    表  4  浓度对UiO-66-NHCl和UiO-66-NH2材料抑菌圈直径的影响对比(±SD mm)
    Table  4.  Comparison of the effect of concentration on the diameter of the inhibition circle of UiO-66-NHCl and UiO-66-NH2
    StrainsSampleDiameter/mm
    200 mg/L300 mg/L400 mg/L500 mg/L600 mg/L
    Staphylococcus aureusUiO-66-NHCl7.88±0.488.55±0.558.96±0.329.58±0.3210.03±0.41
    UiO-66-NH200000
    Escherichia coliUiO-66-NHCl7.94±0.518.27±0.438.73±0.239.21±0.189.98±0.34
    UiO-66-NH200000
    下载: 导出CSV 
    | 显示表格

    表5为UiO-66-NHCl复合材料多次给药皮肤刺激反应实验结果。结果表明,在连续多次给药后,实验组和对照组的皮肤给药部位均未出现红斑、水肿等情况,两者平均反应均值均为0分,因此该材料表现为无刺激性。

    表  5  UiO-66-NHCl多次给药皮肤刺激反应实验结果
    Table  5.  Experimental results of skin irritation response to multiple doses of UiO-66-NHCl
    Dosing time/dComplete skin group (Score)Damaged skin group (Score)
    UiO-66-NHClWaterUiO-66-NHClWater
    10000
    20000
    30000
    40000
    50000
    60000
    70000
    下载: 导出CSV 
    | 显示表格

    采用亚氯酸钠溶液对锆基金属-有机骨架材料UiO-66-NH2进行后合成改性,通过碘钾氧化实验、XRD、SEM、TEM、EDS和XPS等表征分析结果可知,成功制备了UiO-66-NHCl复合抑菌材料,稳定性、抑菌性和皮肤刺激性实验结论如下:

    (1) 在高温、高湿和强光条件下,UiO-66-NHCl的氯负载量分别为原始材料的82%、89.3%和81.2%,均能保持较好的稳定性;

    (2) 抑菌实验表明,与未氯化的UiO-66-NH2材料相比,氯化后的UiO-66-NHCl材料对大肠杆菌和金黄色葡萄球菌均有抑制作用,这是由于活性氯将位于UiO-66-NH2材料上的氨基官能团转化为活性N—Cl结构所导致;

    (3) 皮肤刺激性实验表明,氯化后的UiO-66-NHCl复合抑菌材料对皮肤无刺激性,可用于纺织纤维等防护服的应用。

  • 图  1   石墨烯(GR) (a)和ZnO (b)的SEM图像

    Figure  1.   SEM images of graphene (GR) (a) and ZnO (b)

    图  2   (a) ZnO-GR-TPU/PLA复合线材;(b) 同轴环

    Figure  2.   (a) ZnO-GR-TPU/PLA composite filaments; (b) Coaxial rings

    图  3   ZnO-GR-TPU/PLA复合材料XRD图谱(a)和拉曼光谱(b)

    Figure  3.   XRD patterns (a) and Raman spectra (b) of the ZnO-GR-TPU/PLA composites

    ID/IG—Intensity ratio of peak D to peak G

    图  4   ZnO-GR-TPU/PLA复合粉末的SEM图像:(a) ZN0;(b) ZN2;(c) ZN4;(d) ZN6;(e) ZN8

    Figure  4.   SEM images of ZnO-GR-TPU/PLA composite powder: (a) ZN0; (b) ZN2; (c) ZN4; (d) ZN6; (e) ZN8

    图  5   ZnO-GR-TPU/PLA复合材料的电磁参数:(a) 复介电常数实部ε';(b) 复介电常数虚部ε'';(c) 介电损耗角正切tanδe

    Figure  5.   Electromagnetic parameters of ZnO-GR-TPU/PLA composites: (a) Real part of complex permittivity ε'; (b) Imaginary part of complex permittivity ε''; (c) Dielectric loss tangent tanδe

    图  6   ZnO-GR-TPU/PLA复合材料的Colo-Colo曲线:(a) ZN0;(b) ZN2;(c) ZN4;(d) ZN6;(e) ZN8

    Figure  6.   Colo-Colo curves of ZnO-GR-TPU/PLA composites: (a) ZN0; (b) ZN2; (c) ZN4; (d) ZN6; (e) ZN8

    图  7   ZnO-GR-TPU/PLA复合材料的衰减常数及阻抗匹配

    Figure  7.   Attenuation constant and impedance matching of ZnO-GR-TPU/PLA composites

    8   ZnO-GR-TPU/PLA复合材料的反射损耗图与3D映射图:((a), (b)) ZN0;((c), (d)) ZN2;((e), (f)) ZN4;((g), (h)) ZN6;((i), (j)) ZN8

    8.   Reflection loss diagram and 3D mapping diagram of ZnO-GR-TPU/PLA composite materials: ((a), (b)) ZN0; ((c), (d)) ZN2; ((e), (f)) ZN4; ((g), (h)) ZN6; ((i), (j)) ZN8

    RLmin—Minimal reflection loss; d—Depth; EAB—Effectively absorb bandwidth

    表  1   ZnO-GR-热塑性聚氨酯弹性体橡胶(TPU)/聚乳酸(PLA)复合材料成分

    Table  1   Ingredients of ZnO-GR-thermoplasticpolyurethane (TPU)/polylactic acid (PLA) composites

    SampleMass fraction/wt%
    ZnOGRPLATPU
    ZN00585.59.5
    ZN22583.79.3
    ZN44581.99.1
    ZN66580.18.9
    ZN88578.38.7
    下载: 导出CSV

    表  2   近期文献报道ZnO/石墨烯复合材料的吸波性能

    Table  2   Recent literature reports on the absorption properties of ZnO/graphene composites

    MaterialsLoading/wt%MatrixRLmin (Thickness)Ref.
    Starlike ZnO/RGO75Paraffin−77.50 dB (4.5 mm)[9]
    ZnO@RGO75Paraffin−44.50 dB (4.5 mm)[15]
    RGO@NiO/ZnO70PS−42.50 dB (2.15 mm)[41]
    GR/ZnO hollow sphere50Paraffin−45.05 dB (2.2 mm)[42]
    3D-ZFO/GNs50Paraffin−34.56 dB (1.3 mm)[43]
    ZnO/ZnO nanocrystal@RGO foam25Paraffin−38.00 dB (3.2 mm)[26]
    RGO/ZnO-mrs15Paraffin−38.50 dB (2.0 mm)[44]
    MF/ZnO@Reduced graphene oxide 5Paraffin−63.20 dB (4.1 mm)[33]
    5wt%GR+2wt%ZnO 7PLA−49.20 dB (5.6 mm)This work
    Notes: RGO—Reduced graphene oxide; ZFO—ZnFe2O4; GNs—Graphene nanosheets; mrs—Microrods; MF—Carbonized melamine foame; PS—Polystyrene.
    下载: 导出CSV
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  • 石墨烯因其强介电损耗和高电导率等特点,可作为高性能电磁波衰减材料。为了解决单一石墨烯材料的界面阻抗失配问题,常引入其他材料作为增强其吸波性能。目前,大多数研究将磁性材料与石墨烯结合起来,以获得优异的微波吸收性能,但磁性材料的加入会大大增加吸波材料的密度,并且传统的化学制备法存在工序繁琐、产量低、难以成型等问题。

    为了获得较低密度的吸波复合材料,本文在石墨烯的基础上添加了介电材料ZnO,采用球磨和熔融挤出两步法制备了可用于FDM3D打印的ZnO-石墨烯/PLA/TPU吸波复合材料。通过调节ZnO(2%~8%)含量来改善阻抗匹配进而提高吸波性能。ZnO的加入促进了复合材料的界面极化和偶极极化,实现了吸波材料低密度和强吸收。研究结果表明,当石墨烯含量为5wt%,ZnO添加量仅为2wt%时吸波效果最佳,在5.6 mm厚度下,其最小反射损耗为-49.2 dB,有效吸收带宽为2.0 GHz。同时得益于FDM3D打印的成型方法,本文所制备的复合吸波线材可打印复杂的吸波结构及器件。

    5wt%GR、2wt%ZnO时吸波复合材料的反射损耗图与3D映射图

    ZnO-石墨烯/PLA/TPU吸波复合材料的衰减常数图

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出版历程
  • 收稿日期:  2023-04-26
  • 修回日期:  2023-05-23
  • 录用日期:  2023-06-10
  • 网络出版日期:  2023-06-27
  • 刊出日期:  2024-02-29

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