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1.
蒙脱土(MMT)作为一种天然矿物质,在树脂胶粘剂的增强改性方面应用前景广阔。为了探明蒙脱土增强作用机理,本文采用有机蒙脱土改性脲醛树脂,利用傅里叶红外光谱仪(FTIR)和X射线衍射仪(XRD)分析蒙脱土和改性树脂的化学和晶体结构;并制造木质复合材料,采用纳米压痕技术(NI)比较研究复合材料界面区域树脂的纳米力学性能,测定复合材料的宏观胶合强度。FTIR和XRD分析表明,经十六烷基三甲基溴化铵分析纯(CTAB)改性后的蒙脱土在2 929和2 855 cm-1附近出现新的吸收峰,蒙脱土原土中的金属阳离子和有机阳离子实现有效交换,其(001)面强衍射峰向小角度移动,蒙脱土原土纳米片层的间距从1.51 nm增加至2.71 nm,有助于蒙脱土均匀分散于树脂体系中,并与体系中聚合物分子基团发生化学反应。蒙脱土片层的物理填充、化学反应形成的弹性体结构使得胶粘剂在加载过程中可以有效地分散应力,从而有利于提高脲醛树脂的力学性能,有机蒙脱土改性脲醛树脂的微观弹性模量和硬度分别增加了66.9%和24.2%。改性后树脂的耐水性能得到明显改善,木质复合材料的湿胶合强度增加了约97%。  相似文献   

2.
通过乳液聚合反应合成了一种的新型渗透汽化膜材料-聚甲基丙烯酸甲酯-丙烯酸/蒙脱土[P(MMA-co-AA)/MMT].由该材料制得的渗透汽化膜可用于渗透汽化分离二甲苯.通过X光衍射和透射电镜TEM分析,表明该聚合材料里蒙脱土片层存剥离型状态存在.通过TGA热重分析,在甲基丙烯酸甲酯-丙烯酸共聚物中添加蒙脱土,可以提高聚合材料的热稳定性.并通过渗透汽化实验,发现该纳米复合材料成功应用于渗透汽化分离二甲苯异构体.发现随着膜材料中蒙脱土含量的增加,渗透汽化分离性能不断提高.  相似文献   

3.
龙岩高岭土的苯乙烯原位聚合插层的FTIR和XRD研究   总被引:1,自引:0,他引:1  
以福建龙岩高岭土为主要原料,用沉降的方法得到平均粒径为1.75μm的沉降高岭土。用DMSO插层高岭土,后用苯乙烯单体取代前驱体中的DMSO分子,产物经四氯化碳洗涤后,在马弗炉中270℃本体聚合2h得到高岭土/聚苯乙烯复合物。红外在1 453,1 499和1 606cm-1的吸收振动峰证明了聚苯乙烯的存在。XRD结果显示高岭土层间距0.712nm,苯乙烯聚合后片状结构已经被剥离。热重显示聚苯乙烯占复合物质量的40%,还有约5%的未除去DMSO和4.8%的羟基,估算出高岭土∶聚苯乙烯=1.375∶1(质量比)。扫描电镜也验证了这种剥离。  相似文献   

4.
加热影响凹凸棒土结构的光谱分析   总被引:5,自引:1,他引:4  
凹凸棒土含有四种羟基,3 614 cm-1处的吸收峰是与结构内部的四面体结构和八面体之间的Mg,Al相连羟基的伸缩振动;3 552和3 581 cm-1处的吸收峰是与凹凸棒土孔道边缘的Mg,Al八面体相连的结构水的羟基的对称和不对称伸缩振动;3 415 cm-1处的吸收峰是凹凸棒土中结晶水的羟基振动引起的;1 653 cm-1处的吸收峰是沸石水的吸收峰。将凹凸棒土在不同温度恒温30 min,通过不同的恒温温度各粉样的傅里叶红外光谱(FTIR)和X射线衍射光谱(XRD)的实测和比较,发现温度较低时结构内部的沸石水、结晶水、结构水同时减少;经450 ℃恒温30 min后,结构水被除去,凹凸棒土的晶体结构开始改变;结构羟基非常稳定,600 ℃恒温才会被破坏。文章初步探讨了热处理过程中化学变化过程。  相似文献   

5.
以钠基蒙脱土和有机蒙脱土为研究对象,分别利用29Si魔角旋转核磁共振谱(29Si MAS NMR)、1H-29Si交叉极化/魔角旋转核磁共振谱(1H-29Si CP/MAS NMR)和1H魔角旋转核磁共振谱(1H MAS NMR)对蒙脱土的纯度、蒙脱土片层间的有机插层反应、有机-无机界面相互作用、蒙脱土界面硅原子的受限...  相似文献   

6.
通过差热分析(TGA/DSC)、X射线衍射分析(XRD)、傅里叶变换红外光谱分析(FTIR)等测试技术,对实验室制备的纯净托贝莫来石的高温相变规律进行系统的研究。DSC结果表明,托贝莫来石结构中有四个层间分子水,加热到300 ℃时四个层间分子水逐渐失去。当温度升高到724 ℃时,部分Si—O—H键断裂,失去羟基。XRD结果表明托贝莫来石晶体结构在724 ℃时已经破坏,衍射峰基本消失,煅烧后的样品为无定形的非晶态。当温度持续升高到861 ℃时,发生晶型重构,硅灰石晶体出现,结构转变为有序的、稳定的晶体结构。当温度到达1 000 ℃的时候,完全转变为2M型硅灰石晶体结构。托贝莫来石的高温相变经历了“托贝莫来石→脱水托贝莫来石→脱羟基托贝莫来石→硅灰石”一系列转变过程。  相似文献   

7.
利用X射线衍射(XRD)和傅里叶红外吸收光谱(FTIR)深入研究了青海羊曲剖面砂岩中膨胀性粘土矿物的具体种属和光谱学特征。XRD结果表明,砂岩中粘土矿物以膨胀性粘土矿物为主,含量在97 %以上。样品006面网在1.534  和1.498 均存在明显的衍射峰,表明可能同时含有二八面体和三八面体结构膨胀性粘土矿物。进一步的Li+-300 ℃加热后甘油饱和实验结果显示,大部分样品膨胀性粘土矿物001衍射峰塌陷至9.3~9.9,少数样品膨胀至 ~18 ,表明膨胀性粘土矿物以蒙皂石为主,部分样品含少量皂石。蒙皂石由于部分Li+进入八面体层间,平衡了由于Mg替代Al造成的电价不平衡,从而使得蒙皂石不膨胀。FTIR结果表明,膨胀性粘土矿物同时含有吸附水和结构水,与X射线衍射结果一致。样品在913和842 cm-1出现吸收峰,表明膨胀性粘土矿物八面体层间以Al—Al和Al—Mg为主;部分样品含有Al—Fe(吸收谱峰880 cm-1),指示其为二八面体结构。膨胀性粘土矿物中同时含有Si—O以及Al—O—Si振动峰,表明四面体只有部分Al取代Si。XRD和FTIR均指示研究样品与贝得石和绿脱石有不一样的光谱学特征,而与蒙皂石极为吻合。本研究能有效对膨胀性粘土矿物具体种属进行厘定,对粘土矿物学揭示沉积物物源和气候环境信息具有重要的作用。  相似文献   

8.
一维棒状纳米纤维素及光谱性质   总被引:4,自引:0,他引:4  
Zhang LP  Tang HW  Qu P  Li S  Qin Z  Sun SQ 《光谱学与光谱分析》2011,31(4):1097-1100
采用稀酸预处理纤维素浆粕,结合高压均质的物理方法,制备出一维棒状纳米纤维素.通过傅里叶红外光谱(FTIR),X射线衍射(XRD),热重分析(TGA),原子力显微镜(AFM)和透射电镜(TEM)等方法对纳米纤维素光谱性能和形貌结构进行了表征.结果表明,制得的纳米纤维素与纤维素浆粕具有相同的红外特征官能闭,但分子内氢键缔合作用被部分破坏.纳米纤维素与纤维素浆粕同属于纤维素I的晶形类型,结品度从59%提高至70%,仍保持结晶区与无定形区共存的状态.纳米纤维素的分解温度为330℃,热稳定性低于纤维素浆粕,失重温度从292℃持续至500℃,有两个明显失重阶段.纳米纤维素长度为数百纳米,宽度为数十纳米的棒状形态,易产生团聚现象.  相似文献   

9.
模拟分子的结构与行为有助于更深刻地分析聚乙烯/蒙脱土(PE/MMT)纳米复合材料力学性能变化的微观机理.为此,以分子动力学为依据,利用Materials studio构建聚乙烯/蒙脱土纳米复合材料模型.在普适力场作用下,通过X射线衍射、径向分布函数以及相互作用能分别对纳米复合材料和纳米蒙脱土的微观结构和性能进行分析.仿真结果表明:有机化处理使蒙脱土的层间距增大79%;在蒙脱土质量分数为4.0 wt%时,PE/MMT纳米复合材料中存在明显的氢键作用,聚乙烯分子和蒙脱土片层间的相互作用能高达-390 kcal/mol,界面作用得到明显提高,最终形成稳定的材料结构,同时力学性能相比纯聚乙烯材料也得到改善,其中杨氏模量、体积模量以及剪切模量分别提高38%,21%和40%.分子模拟结果与实验实测结果相符,并验证了有机化蒙脱土改性聚乙烯绝缘材料会产生氢键作用.  相似文献   

10.
氧化石墨烯是由sp~2和sp~3两种杂化碳原子构成的单原子层二维网络结构,富含羟基、环氧基和羧基多种含氧基团,是众多功能化石墨衍生物的前驱体;其中,羟基和环氧基主要分布在氧化石墨烯片层表面,羧基主要位于片层结构的边缘,利用氧化石墨烯表面的羟基或环氧基可以得到垂直于表面的有序结构材料,利用边缘的羧基可得到多种悬垂结构的功能复合材料。利用不同氧化方法和同种氧化剂不同用量进行氧化得到石墨烯的氧化度不同,从而功能化后的石墨烯性能有很大差异。氧化石墨烯的氧化度测定是对其进行改性的基础。科学家们通过XRD, XPS, FTIR, Zeta,拉曼光谱法等研究石墨烯中不同杂化的碳原子和氧原子比例,但是几乎没有报道可以直接测量氧化石墨烯上含氧官能团的量。主要通过苯酚作为标准利用傅里叶变换红外光谱建立一种氧化石墨烯片层间羟基含量的测定方法。采用化学氧化-还原法制备薄层氧化石墨烯(GO),由于苯酚和GO具有相似骨架结构,以苯酚的红外光谱谱图可以作为标准图谱,苯酚红外光谱在1 597, 1 500和1 474 cm~(-1)为其苯环结构的伸缩振动吸收峰;在1 374 cm~(-1)处为苯环C—H面内弯曲振动吸收峰;而在1 234 cm~(-1)处为酚类C—OH伸缩振动吸收峰。氧化石墨烯的红外谱图中1 630 cm~(-1)出现类苯环骨架CC的伸缩振动吸收峰,在1 400 cm~(-1)出现氧化石墨烯片层上C—O(H)的伸缩振动吸收峰。利用测试苯酚中苯环和羟基C—OH吸收峰面积的比值,与氧化石墨烯上类苯环结构CC和片层上羟基C—O(H)吸收峰面积的比值,可以得到片层上羟基含量的值。同时利用场发射扫描电镜,透射电镜,原子力显微镜,紫外可见分光光度计和激光拉曼光谱仪对计算结果进行验证,结果表明类比红外光谱法,可以作为测定氧化石墨烯片层上羟基含量的一种有效方法。  相似文献   

11.
粘土矿物在催化木质素形成腐殖质方面具有重要贡献。为有效阐明微生物-木质素-粘土矿物三者间的关系,探明矿物-菌体残留物的结构特征,采用液体摇瓶培养法,以木质素为碳源,通过添加高岭石和蒙脱石,在接种复合菌剂后启动110 d液体培养,期间动态收集矿物-菌体残留物,利用傅里叶红外光谱及扫描电子显微镜技术对其结构特性进行了研究。结果表明:高岭石颗粒边缘多由管状体卷曲而成,在参与微生物利用木质素形成矿物-菌体残留物后,连片状细小颗粒结构进一步团聚,结合更加紧凑,短管状结构增多,但整体仍保持多水高岭石的结构特征;在初始富营养条件下,高岭石能够促进微生物繁衍,使大量菌体聚集于高岭石表面,掩蔽了Si-O和Si-O-Al键,且矿物-菌体残留物中脂族碳结构比例增加;菌体中多糖物质通过含氧官能团与高岭石表面的水化层在多个部位形成氢键,氢键的形成对于高岭石稳定木质素及其降解产物具有重要作用,芳香碳结构比例和多糖类物质含量随培养时间逐渐增加,而后复合菌株对掩蔽在矿物表面的菌体进行二次利用,使高岭石Si-O-Al键重现;蒙脱石多由浑圆的颗粒结构组成,接种微生物可使其表面产生溶蚀,团粒结构遭到破碎;与10 d相比,历经30 d培养所得矿物-菌体残留物中的多糖类物质增多,使原本归属蒙脱石Si-O-Si及Si-O结构的1 034~1 038 cm-1处吸收峰强度增加,而后因多糖类物质与蒙脱石表面羟基发生缔合,又使该处吸收峰强度减弱,同时发生了氢键键合,该作用是蒙脱石-微生物-木质素间相互作用、形成矿物-菌体残留物的主要机制;高岭石在稳定有机碳方面的能力要高于蒙脱石,更易促进HS前体物质的形成。  相似文献   

12.
Temperature-induced desorption behavior of water from methylcellulose (MC) film was investigated by a novel microscopic Fourier transform infrared (FT-IR) spectroscopy equipped with thermal analyzer (thermal FT-IR microscopic system) and thermogravimetric analysis (TGA). The result indicates that the weight loss of water from MC film was markedly correlated to the IR spectral changes of OH stretching (3000-3800 cm−1) and bending (1649 cm−1) modes of water molecules. The shift of OH stretching mode from 3461 to 3481 cm−1 was accompanied with the water loss from MC film induced by temperature effect. Two stages of water desorption from MC film were proposed: the first stage within the 35-65 °C had a dramatic IR peak shift from 3461 to 3477 cm−1 and accompanied with a largest weight loss of water from MC film, which might be mainly due to the desorption of free water with minor weakly hydrogen-bonded water; the second stage beyond 65 °C would be desorption of moderately hydrogen-bonded bound water, due to the gradual IR spectral shift from 3477 to 3481 cm−1 and a slower weight loss of water from MC film. The changes in peak area ratio of 1649 cm−1/1374 cm−1 with the temperature also confirmed the IR spectral peak shift of the OH stretching mode via the water loss from MC film. The temperature-dependent dissociation of intermolecular and intramolecular hydrogen bonds within water molecules and/or between water/MC interaction might be responsible for the desorption kinetics of water from MC film.  相似文献   

13.
Three zwitterionic surfactants, dodecyl dimethyl carboxylbetaine (DCB), dodecyl dimethyl sulfobetaine (DSB) and N-dodecyl-β-aminoprpionate (DAP), intercalated into NiZn-layered hydroxide salts (NZL-DCB, NZL-DSB and NZL-DAP) were synthesized by the coprecipitation method. The effect of surfactant content, pH, temperature and time of hydrothermal treatment on preparation was investigated and discussed. The NZL-DCB, NZL-DSB and NZL-DAP were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetry analysis and differential thermal analysis (TGA/DTA). The results showed that basal spacings of NZL-DCB, NZL-DSB and NZL-DAP were around 3.45, 3.68 and 3.94 nm, respectively. DCB, DSB and DAP probably form an overlapped bilayer in the gallery. TGA/DTA data indicated that NZL-DCB, NZL-DSB and NZL-DAP displayed three loss weight stages: loss of adsorbed and structural water, dehydroxylation of matrix and decomposition of nitrate ions, decomposition and combustion of surfactants. Furthermore, chemical analysis data, BET surface area and scanning electron microscopic (SEM) were also measured and analyzed.  相似文献   

14.
近年来,低温热处理刚玉出现在宝石交易市场,由于其特征容易与天然刚玉混淆,如何鉴定低温热处理刚玉成为宝石实验室的研究热点。在弱氧化氛围,360,610和650 ℃条件下,先后对9粒刚玉进行了热处理实验,并采用显微拉曼定性分析刚玉中的包裹体、显微镜下观察包裹体形貌、显微红外光谱分析含水矿物包裹体中羟基的特征峰等方法,对刚玉低温热处理前后的特征进行了对比研究。热处理实验揭示:600 ℃左右温度、弱氧化氛围已能有效去除刚玉中的蓝色调,并增强红色,可达到热处理改善或改变刚玉颜色的目的。研究结果表明:针铁矿、高岭石、勃姆石等含水矿物包体主要存在于刚玉的开放裂隙中,硬水铝石、磷灰石、云母等含水矿物包体主要存在于刚玉晶体中。针铁矿热处理前红外光谱可显示与羟基相关的3 435 cm-1吸收峰,并伴有以3 185 cm-1为中心的吸收宽带,经360 ℃热处理后相关吸收消失,其颜色由亮黄色变为红色;高岭石热处理前红外光谱在3 620,3 648,3 670和3 698 cm-1附近显示一组与羟基相关的吸收峰,经610 ℃热处理后相关吸收峰消失;勃姆石热处理前红外光谱显示与羟基相关的3 086和3 311 cm-1吸收峰,经610 ℃热处理后相关吸收峰消失。硬水铝石包裹体通常呈针状,热处理前红外光谱显示与羟基相关的1 980和2 110 cm-1吸收峰,经610 ℃热处理后相关吸收峰消失,但仍保持针状晶形假像;磷灰石包体通常呈透明柱状或粒状晶形,由于OH与F相互作用,红外光谱在3 550 cm-1附近显示与羟基相关的吸收峰,610 ℃热处理后相关吸收峰仍然存在,磷灰石包体的形貌未见改变;白云母呈近透明无色片状晶形分布于刚玉中,红外光谱在3 624 cm-1附近显示与云母中羟基相关的吸收峰,650 ℃热处理后这一吸收峰仍然存在,云母的形状未见变化,透明度略微降低。通过实验,证明含水矿物包裹体对于鉴定低温热处理刚玉具有重要作用。  相似文献   

15.
采用程序升温热解吸(TPD/TDS)方法对Li4SiO4陶瓷小球的水解吸行为进行了实验研究。结果表明:水解吸过程中主要存在四个解吸峰;其中100℃附近的峰可解释为物理吸附水;150,250,400℃附近的峰可分别解释为以氢键、Li-OH和Si-OH配位键形式存在的化学吸附水。氚的释放与水的解吸几乎同步进行,且氚的释放形式主要为氚水(HTO),据此推测,氚水可能存在三种释放机制:(1)-OT+H2O→-OH+HTO;(2)-OH+-OH→H2O,-OT+H2O→-OH+HTO;(3)-OT+-OH→HTO。  相似文献   

16.
The effects of molecular weight on the thermal degradation behavior of poly(α-methyl styrene) (PAMS) was investigated by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and thermogravimetric analysis (TGA). The Py-GC/MS analysis results showed that the degradation of PAMS with different molecular weights in nitrogen produced only the monomer, alpha-methylstyrene. The TGA results showed a pronounced reduction in the decomposition temperature with increasing molecular weight. The degradation kinetic parameters, calculated by the Kissinger and the Coats–Redfern methods, further revealed that the activation energy and the pre-exponential factor decreased with increasing molecular weight. Most importantly, the degradation order of the PAMS in nitrogen remained around 1, independent of the molecular weight, suggesting the maintenance of the depolymerization mechanism. All the above results provided an insight into the effects of molecular weight on the thermal degradation behavior of PAMS.  相似文献   

17.
印章石是我国特有的具有民族历史文化特色的艺术品,江西“高洲石”是近年来新发现并在市场上流通的印章石品种。采用X射线粉晶衍射(XRD)、X射线荧光光谱分析(XRF)、红外光谱分析(FTIR)、扫描电镜(SEM)及差热分析(DTA)对“高洲石”的矿物学特征和谱学特征进行了系统的研究。粉晶衍射结果表明,“高洲石”的主要矿物成分为高岭石族矿物和叶蜡石,其次含有少量的绢云母和伊利石等。其中高岭石和地开石多型可通过18°~40°()范围内一系列地开石特有的衍射峰鉴别。“高洲石”中高岭石族矿物同时出现高岭石和地开石的特征衍射峰,主要为高岭石-地开石过渡矿物。“高洲石”主要化学成分为SiO2和Al2O3,次要成分为Fe2O3和K2O和Na2O等,这与高岭石族矿物的化学成分相一致。红外光谱的结果显示“高洲石”中高岭石-地开石过渡矿物在高频区一般出现3 689, 3 645和3 615 cm-1三个谱带,其中归属于面外羟基振动的3 689 cm-1谱带和面内羟基振动的3 615 cm-1谱带强度近似相等,部分略有变化,其变化因含高岭石层或地开石层较多造成。扫描电镜下观察到“高洲石”中高岭石矿物的形态主要呈直径为0.5~4 μm的不规则片状或假六方板状,与我国其他产地印石的扫描电镜特征较为相似。差热分析结果表明高岭石族矿物的脱羟吸热谷温度与其矿物种属有一定对应关系,同时此温度还受矿物颗粒大小的影响。综合研究表明,“高洲石”的矿物类型与我国四大印石(寿山石、昌化石、青田石、巴林石)相似,作为四大印石的替代品,“高洲石”具有广阔的市场前景。  相似文献   

18.
Long-term chemical and structural stability of an ion conducting ceramic is one of the main criteria for its selection as an electrolytic membrane in energy plant devices. Consequently, medium density SrZr0.9Er0.1O3-δ (SZE) anhydrous proton conducting ceramic – a potential electrolyte of SOFC/PCFC, was analysed by neutron diffraction between room temperature and 900 °C. After the first heating/cooling cycle, the ceramic pieces were exposed to water vapour pressure in an autoclave (500 °C, 40 bar, 7 days) in order to incorporate protonic species; the protonated compound was then again analysed by neutron diffraction. This procedure was repeated two times. At each step, the sample was also controlled by TGA and Raman spectroscopy. These studies allow the first comprehensive comparison of structural and chemical stability during the protonation/deprotonation cycling. The results reveal good structural stability, although an irreversible small contraction of the unit-cell volume and local structure modifications near Zr/ErO5[] octahedra are detected after the first protonation. After the second protonation easy ceramic crumbling under a stress is observed because of the presence of secondary phases (SrCO3, Sr(OH)2) well detected by Raman scattering and TGA. The role of crystallographic purity, substituting element and residual porosity in the proton conducting perovskite electrolyte stability is discussed.  相似文献   

19.
A total of 30 clay samples were collected from the area around Riyadh city, Saudi Arabia. A complete chemical analysis was carried out using different techniques. X-ray diffraction studies showed that the clay samples were mainly of the smectite group with traces of the kaolinite one. The samples studied were classified as nontronite clay minerals. One of the clay fraction has been studied by Mössbauer spectroscopy as raw clay fraction and after being fired at 950–1,000 °C. The Mössbauer spectra showed accessory iron compounds in the form of hematite and goethite. The structural iron contents disintegrate on firing transforming into magnetic iron oxide and a paramagnetic small particles iron oxide.  相似文献   

20.
《Composite Interfaces》2013,20(7-9):923-935
Lignin-based thermoplastic copolyester was synthesized for eco-friendly polymers and composite applications using lignin as a macromonomer to form a high molecular weight polymer. Kraft lignin was polymerized with sebacoyl chloride in the presence of triethylamine in N,N-dimethylacetamide (DMAc), and the molecular weight of the synthesized polymer was controlled by the polymerization temperatures and [COCl]/[OH] ratios providing up to 39 000 corresponding to 4–5 repeating units of lignin macromonomers. The glass transition temperature of the synthesized polymer was difficult to measure due to the random distribution of functional groups and irregular configurational or conformational arrangement of natural lignin. Therefore, the complex electric modulus (CEM) technique was used to determine the glass transition of the synthesized polymer to give around 70°C measured by the peak of the imaginary part of CEM. The synthesized lignin-copolyester exhibited good thermal stability up to 200°C in TGA analysis and, thus, it was possible to shape the synthesized polymer using the solvent casting or hot-melt processing techniques at 120°C–140°C without generating odor, fume or irritation. Although the molecular weight should further be increased in the future, the developed methodology may help to exploit new applications for eco-friendly sustainable materials in various fields.  相似文献   

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