石墨烯复合材料对ABS性能影响的研究

首先合成含有6个羟基的三亚苯衍生物,并通过铈盐和羟基组成的氧化还原体系合成星型聚丙烯腈(SPAN)。利用星型聚丙烯腈和石墨烯之间的π-π键相互作用合成易于分散的星型聚丙烯腈/石墨烯复合材料,再利用改性后的石墨烯对ABS进行共混改性。研究了改性石墨烯的加入对ABS力学性能和电学性能的影响。     

氧化石墨烯/纳米羟基磷灰石复合粉体的制备及其细胞毒性

采用改进Hummers法制备了氧化石墨烯（GO）,再与Ca（NO₃）₂和（NH₄）₂HPO₄通过溶液离子共滴定法制备GO/纳米羟基磷灰石（nHAP）复合粉体材料。利用TEM、XRD、FTIR、XPS等分析了GO/nHAP复合粉体的形貌、相结构、官能团以及元素化学价态变化,最后通过3-（4,5-二甲基噻唑-2）-2,5-二苯基四氮唑溴（MTT）法对GO/nHAP粉体复合材料的生物学性能进行检测。结果表明：GO/nHAP复合粉体中nHAP呈现晶簇针状,且分散均匀,尺寸约为50~100 nm,GO片层尺寸为1 000~4 000 nm;nHAP在GO表层原位形核,并沿着（112）晶面择优生长,两相通过化学键的形式结合;GO/nHAP复合粉体材料无细胞毒性。     

基于化学气相沉积石墨烯/PEDOT-PSS共混复合材料的导电薄膜

采用液相剥离技术制备基于化学气相沉积（CVD）石墨烯/聚乙撑二氧噻吩-聚苯乙烯磺酸（PEDOT-PSS）共混复合材料的导电薄膜。采用原子力显微镜和SEM表征石墨烯/PEDOT-PSS复合薄膜的微观结构;通过紫外吸收谱、X射线光电子能谱、FTIR等分析技术探索该共混复合薄膜的导电机制。结果表明：石墨烯/PEDOT-PSS导电薄膜具有优异的电学特性,其方阻约为8 Ω/□;表面分析表明,石墨烯与PEDOT主链中五元噻吩发生π-π共轭效应,由此引起两作用体之间电子云密度的变化,该变化增加了PEDOT主链的载流子离域化程度,有利于PEDOT导电性的提升,同时提高石墨烯的载流子浓度,使CVD石墨烯/PEDOT-PSS复合薄膜的导电能力增强。     

三维立体介孔结构的海藻酸钠/氧化石墨烯复合气凝胶的制备及其对亚甲基蓝的吸附

为了有效去除废水中的染料,本论文以海藻酸钠（SA）和氧化石墨烯（GO）为原料,采用一步水热法制备海藻酸钠/氧化石墨烯（SA/GO）复合水凝胶,并通过冷冻干燥法得SA/GO复合气凝胶。利用FT-IR、XRD、SEM、TEM、N₂等温吸附-脱附、接触角来表征SA/GO复合气凝胶并研究其吸附性能。结果表明,SA/GO复合气凝胶是具有三维立体结构的多孔材料,BET比表面积约为580.54 m²·g^-1。讨论了SA/GO复合气凝胶对亚甲基蓝（MB）溶液吸附过程的影响因素,在碱性条件下,吸附效果最好,吸附率可达99.41%,吸附量可达248.53 mg·g^-1,并表现出优异的循环再生性。     

球磨共混制备优异抗原子氧性能的氧化石墨烯/聚酰亚胺复合薄膜

通过简单的机械共混（球磨共混）和高温压制的方法,制备了一系列具有良好抗原子氧（AO）性能的氧化石墨烯/聚酰亚胺（GO/PI）复合薄膜。微量（0.5wt%） GO的引入可使GO/PI复合薄膜的抗AO性能提高17.9%。同时,含0.5wt% GO的GO/PI复合薄膜也表现出良好的热稳定性能和力学性能。热重分析表明,含0.5wt% GO的GO/PI复合薄膜在质量损失为5%时的温度（T_d5）为519.4℃,比纯PI薄膜高14.7℃;拉伸强度为111.9 MPa,杨氏模量为2.1 GPa,与纯PI薄膜相比,分别提高了4.3 MPa和0.1 GPa。与传统的原位聚合法相比,机械共混-高温压制的方式更易于操作和控制,使具有优异综合性能的GO/PI复合薄膜的大规模量产成为可能。     

电子受体材料功能化还原氧化石墨烯的结构和光学性能

采用Hummers法制备氧化石墨烯(GO),利用水热法对GO分别还原5 h和10 h制得两种还原氧化石墨烯(5-RGO和10-RGO),进一步用异氰酸苯酯对还原前后的氧化石墨烯材料进行改性,即得功能化氧化石墨烯和功能化还原氧化石墨烯(SPFGO、5-SPFRGO和10-SPFRGO)。以功能化还原氧化石墨烯材料为电子受体,聚3-己基噻吩(P3HT)为电子给体,制备复合膜。结果表明:GO由3-5层组成,经水热还原后样品表面仍含有—CO,—COOH等含氧官能团;功能化后石墨烯在邻二氯苯中分散性良好,与P3HT能级相匹配,满足作为聚合物太阳能电池受体材料要求;以5-SPFRGO做为受体材料与P3HT复合制备的复合膜表面规整致密,光吸收强度高,荧光光谱强度低,性能最优。     

氧化石墨烯的制备和定性定量分析

以鳞片石墨为原料,采用硫酸和高锰酸钾,通过化学插层氧化-破碎方法制备了氧化石墨烯(GO),通过扫描电镜(SEM)、激光粒度分析、红外光谱(FT-IR)、紫外-可见光谱(UV-vis)和原子力显微镜(AFM)等测试手段对所制备的氧化石墨烯进行了分析和表征。结果发现230 nm附近的紫外可见光谱可以把氧化石墨烯与氧化石墨进行区分。结果表明紫外光谱可对氧化石墨烯溶液进行定性分析和定量分析。通过这一方法可获得氧化石墨烯制备的较优条件。机理分析结果表明:氧化石墨烯的不连续的π-π*共轭体系为主的结构特点是其紫外光谱在230 nm附近产生多个强度不同的吸收峰的原因。     

石墨烯-聚苯胺复合氨敏膜的制备及应用

以石墨烯和苯胺为原料,采用原位自组装技术制备了石墨烯-聚苯胺(PANI)复合氨敏膜。利用紫外-可见光谱、扫描电镜对薄膜结构、微观形貌进行了表征;测试了基于复合薄膜的氨气传感器的响应性能;分析了薄膜与氨气分子的作用机理,并研究了石墨烯掺杂量和制备工艺对薄膜性能的影响。结果表明,石墨烯-聚苯胺复合薄膜对氨气具有良好的响应,其气敏特性明显优于单一的石墨烯薄膜和石墨烯/聚苯胺分层薄膜,分析认为石墨烯不仅为苯胺聚合提供了基体(成核模板),增大复合薄膜的比表面积,同时对聚苯胺具有掺杂作用,在复合薄膜中形成了π-π共轭结构。     

离子液体改性氧化石墨烯/双马来酰亚胺复合材料的介电性能

通过Hummers法得到氧化石墨,超声剥离得到氧化石墨烯(GO),然后通过1-(2-氨基乙基)-3-甲基咪唑溴盐与氧化石墨烯反应得到改性氧化石墨烯(WGO),最后用原位聚合法将WGO与N,N-二氨基二苯甲烷型双马来酰亚胺(BMI)、O,O-二烯丙基双酚A(BA)的共聚物复合制备出BMI/BA/WGO复合材料。采用扫描电镜和原子力显微镜等测试方法对复合材料进行了表征,并对其介电性能进行了研究。结果表明,制备了性能优异的WGO,且WGO含量的增加提高了复合材料的介电常数和介电损耗,在WGO的质量分数为4.13%左右时出现渗流效应,BMI/BA/WGO复合材料的介电常数突增。1-(2-氨基乙基)-3-甲基咪唑溴盐可以明显改善GO在复合材料中的分散性,同时可提高材料的介电常数。     

丙烯酸功能化纳米氧化石墨烯/丙烯酸酯复合乳液的制备及性能

以烯丙基磺酸钠（ALS）为可聚合乳化剂，采用种子乳液聚合法制备丙烯酸功能化纳米氧化石墨烯（FAGO）/丙烯酸酯复合乳液。通过红外光谱、XRD表征GO、FAGO的结构，通过SEM和TEM观察GO、FAGO、纳米FAGO/丙烯酸酯复合乳液的形貌。结果表明，丙烯酸上的羧基与GO羟基反应生成了酯键；FAGO的边缘发生扭曲变形，局部产生较多褶皱，体系的不规整度显著增加；纳米FAGO/丙烯酸酯乳胶粒子呈规则的球形。纳米粒径电位分析表明，纳米FAGO/丙烯酸酯复合乳液粒径大小均一，分散性良好，随着ALS加入量的增加，纳米FAGO/丙烯酸酯乳胶粒子的粒径逐渐减小，其分散性指数（PDI）先减小后增大，相应的Zeta电位逐渐升高，乳液的黏度逐渐增大，乳胶膜耐水性变差，当ALS用量为0.8wt%时，纳米FAGO/丙烯酸酯复合乳液综合性能最佳。     

含磷石墨烯的制备及复合涂层的耐蚀性能

以植酸(PhA)为原料,采用热解法制备含磷石墨烯(PhA-G),并以硅树脂(SiR)为成膜物制备含磷石墨烯/硅树脂(PhA-G/SiR)复合防腐蚀涂层。通过拉曼光谱和XPS分析含磷石墨烯的结构,通过SEM、TEM和AFM观察含磷石墨烯的形貌,通过接触角、吸水率、电化学阻抗谱、极化曲线和盐雾实验等研究复合涂层的耐蚀性能。结果表明：相比于纯SiR涂层和氧化石墨烯/硅树脂(GO/SiR)复合涂层,PhA-G/SiR复合涂层对金属的保护作用更好;当含磷石墨烯添加量为3%(质量分数)时,PhA-G/SiR复合涂层表现出较好的疏水性和优异的防腐蚀性能,其接触角为103.5°,吸水率为3.72%;腐蚀电流密度为3.53×10^-10 A/cm²,电化学阻抗值达到3.82×10⁷ Ω·cm²,耐盐雾达到960 h。     

三维多孔结构聚苯胺/石墨烯复合材料的制备及电化学性能

以自制聚苯胺水凝胶和氧化石墨烯为原料采用原位聚合法和溶液灌注法制备三维多孔结构的聚苯胺/氧化石墨烯复合材料,然后在氢碘酸的还原下制备聚苯胺/石墨烯复合材料。采用红外光谱法、场发射扫描电子显微镜和热重分析法对制备的复合材料的结构、形貌和组成进行表征,并采用三电极测试方式对其电化学性能进行测试。结果表明,氧化石墨烯的掺入能有效防止聚苯胺和氧化石墨烯的团聚和堆叠问题,获得了具有良好三维多孔结构的聚苯胺/氧化石墨烯复合物;聚苯胺/氧化石墨烯复合材料被氢碘酸还原后,得到的聚苯胺/石墨烯复合材料的热稳定性有所降低,但其比电容和导电性等有了很大的提高,在电流密度为0.5 A/g时,PANI/GO和PANI/r GO的比电容分别为240.38 F/g和321.91F/g。     

石墨烯装载不同含量钴锌铁氧体及其电磁行为对比

以天然鳞片石墨为原料制备氧化石墨(GO), 应用水热法制备钴锌铁氧体(Co_0.5Zn_0.5Fe₂O₄), 并将两者制备成石墨烯(rGO)/Co_0.5Zn_0.5Fe₂O₄复合材料。采用X射线衍射(XRD)、拉曼光谱(Raman)、红外光谱(FT-IR)研究rGO/Co_0.5Zn_0.5Fe₂O₄的结构; 应用透射电子显微镜(TEM)和矢量网络分析仪(VNA)研究不同复合比例对rGO/Co_0.5Zn_0.5Fe₂O₄复合材料形貌、电磁损耗特性、德拜弛豫模型及电磁响应行为的影响。结果表明: 复合反应后的GO在XRD图谱中主衍射峰由2θ=9.74°变化为2θ=24.15°, 且红外光谱图中显示含氧官能团消失, 均说明GO成功还原为rGO。透射电子显微镜图中可以看到Co_0.5Zn_0.5Fe₂O₄嵌布在rGO上。复合反应过程中, 当钴锌铁氧体的含量增大, 分散性逐渐减弱。Co_0.5Zn_0.5Fe₂O₄与GO质量比为2 : 1时制备的rGO/Co_0.5Zn_0.5Fe₂O₄复合材料的吸波性能最佳, 在15.11 GHz处反射率达到最小值-36.89 dB, 有效吸波频带宽为3.74。     

Graphene oxide-filled conducting polyaniline composites as methanol-sensing materials

Polyaniline/graphene oxide (PANI/GO) composites were prepared by polymerization of aniline monomer in the presence of GO under acidic conditions. The synthesized samples were characterized by Fourier transform infra red spectroscopy, ultraviolet–visible absorption, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. The direct current electrical conductivity of the composite was calculated by a four-probe technique. It is found that the conductivity dramatically increased to 241 S m^?1 for PANI/GO (5 wt%) composite at 110 °C compared to pure PANI (7.5 S m^?1). The composite material was investigated as a methanol vapour sensor and compared with pure PANI. The methanol-sensing characteristics of the prepared composite was monitored by measuring the change in electrical resistivity on exposure to methanol vapour at different concentrations. The resistivity of PANI increases on exposure to methanol vapour because of strong hydrogen bonding between methanol with the polymer chain. A density functional theory study was carried out to verify the proposed concept of hydrogen bonding between the polymer chains and methanol. The presence of GO in PANI/GO composite increases the sensitivity towards methanol as compared with the pure PANI.     

Direct nucleation of silver nanoparticles on graphene sheet

Silver (Ag) nanoparticles were synthesized on the surface of graphene sheet by the simultaneous reduction of Ag+ and graphene oxide (GO) in the presence of simple reducing agent, hydrazine hydrate (N2H4 x H2O). Both the Ag+ and GO were reduced and Ag+ was nucleated onto graphene. GO flakes were prepared by conventional chemical exfoliation method and in the presence of strong acidic medium of potassium chlorate. Silver nanoparticles were prepared using 0.01 M AgNO3 solution. The reduced GO sheet decorated with Ag is referred as G-Ag sample. G-Ag was characterized by FTIR (Fourier transform infrared) spectroscopy using GO as standard. An explicit alkene peak appeared around 1625 cm(-1) was observed in G-Ag sample. Besides, the characteristic carbonyl and hydroxyl peaks shows well reduction of GO. The FTIR therefore confirms the direct interaction of Ag into Graphene. SEM (scanning electron microscopy) and TEM (transmission electron microscopy) analysis were performed for morphological probing. The average size of Ag nanoparticles was confirmed by around 5-10 nm by the high-resolution TEM (HRTEM). The Ag quantum dots incorporated nanocomposite material could become prominent candidate for diverse applications including photovoltaic, catalysis, and biosensors etc.     

液相制备石墨烯/硫复合材料及其在锂硫电池正极中的应用

采用氧化石墨烯(grapheneoxide,GO)作为制备石墨烯的前驱体,通过液相还原自组装过程与硫纳米颗粒进行复合,获得了高性能的还原氧化石墨烯/硫(r GO/S)复合正极材料。利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、拉曼光谱、X射线光电子能谱分析(XPS)等对材料微观形貌与结构进行表征。结果表明:硫纳米颗粒均匀分布在石墨烯片层间,并且硫纳米颗粒被石墨烯片层有效地封装,硫在35-r GO/S复合物中的质量分数高达83.6%。该35-r GO/S复合正极在0.2C电流密度下初始放电容量可达1197.3mAh·g^-1,经过200次循环后容量仍保持在730mAh·g^-1左右,表现出优异的循环性能。     

氧化石墨烯/丝素蛋白凝胶结构及其性能研究

目前医用凝胶材料普遍存在力学强度较差及生物降解速度过快等问题。以蚕丝丝素蛋白(SF)凝胶为基础材料,加入氧化石墨烯(GO),并将1-乙基-(3-二甲基氨基丙基)碳二亚胺盐酸盐(EDC)及N-羟基琥珀酰亚胺(NHS)作为交联剂制备SF/GO复合凝胶,旨在改善凝胶材料的力学性能,使其在保证复合凝胶材料应有的力学强度的同时,发挥丝素蛋白、氧化石墨烯的生物学效应及凝胶材料的多孔支架作用。实验结果显示,EDC的加入可以使得SF、GO共混形成稳定、均匀的无规卷曲结构,扫描电镜(SEM)显示SF/GO凝胶具有典型的多孔结构。GO的加入可以有效缩短复合材料的凝胶时间,同时复合凝胶材料的力学性能得到明显改善,其压缩强度提高40%以上。GO的加入还可明显延长材料的降解时间。基于SF/GO的复合凝胶在组织修复及再生领域具有较好的应用前景。     

Preparation and properties of polystyrene nanocomposites with graphite oxide and graphene as flame retardants

In this study, graphite oxides (GOs) with different oxidation degrees and graphene nanosheets were prepared by a modified Hummers method and thermal exfoliation of the prepared GO, respectively. Polystyrene (PS)/GO and PS/graphene nanocomposites were prepared via melt blending. X-ray diffraction results showed that GOs and graphene were exfoliated in the PS composites. It could be observed from the scanning electron microscope images that GOs and graphene were well dispersed throughout the matrix without obvious aggregates. Dynamic mechanical thermal analysis suggested that the storage modulus for the PS/GO1 and PS/graphene nanocomposites was efficiently improved due to the low oxygen content of GO1 and the elimination of the oxygen groups from GO. The flammability of nanocomposites was evaluated by thermal gravimetric analysis and cone calorimetry. The results suggested that both the thermal stability and the reduction in peak heat release rate (PHRR) decreased with the increasing of the oxygen groups in GOs or graphene. The optimal flammability was obtained with the graphene (5 wt%), in which case the reduction in the PHRR is almost 50 % as compared to PS.     

低温剥离法制备高性能石墨烯/ZnO复合材料

采用氧化石墨和七水合硫酸锌作为初始反应物,在低温下(80℃)合成了氧化石墨/ZnO,然后通过低温剥离法制备了高质量石墨烯/ZnO(GNS/ZnO)复合材料.采用X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱、热重分析仪(TG)、X射线光电子能谱(XPS)、拉曼光谱(RS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等分析手段对石墨烯/ZnO样品进行了表征.结果表明:氧化石墨还原彻底,纳米ZnO成功地负载到了石墨烯上,有效地减少了石墨烯片层间的团聚现象.通过对ZnO和石墨烯/ZnO荧光性能测试,结果表明:石墨烯/ZnO发生了荧光淬灭现象,在光电子领域拥有广阔的应用前景.     

Effects of functional groups on the graphene sheet for improving the thermomechanical properties of polyurethane nanocomposites

Dispersibility of graphene sheets in polymer matrices and interfacial interaction are challenging for producing graphene-based high performance polymer nanocomposites. In this study, three kinds nanofillers; pristine graphene nanoplatelets (GNPs), graphene oxide (GO), and functionalized graphene sheet (FGS) were used to prepare polyurethane (PU) composite by in-situ polymerization. To evaluate the efficacy of functional groups on the graphene sheets, PU reinforced with GNPs, GO, and FGS were compared through tensile testing and dynamic mechanical thermal analysis. The Young's moduli of 2 wt% GO and FGS based PU nanocomposites were found significantly higher than that of same amount of GNPs loading as an evidence of the effect of functional groups on graphene sheets for the mechanical reinforcement. The strong interaction of FGS with PU was responsible to exhibit notably high modulus (25.8 MPa) of 2 wt% FGS/PU composite than the same amount of GNPs and GO loading even at elevated temperature (100 °C).