氯化钙对尼龙6无定形转变过程的在位红外研究

采用在位红外分析、X射线衍射方法研究了氯化钙对尼龙 6结晶的影响。结果表明 ,随尼龙 6中氯化钙含量的增加 ,尼龙 6的结晶度逐渐减小直至变为无定形态。由于氢键作用使尼龙 6分子链规整排列产生结晶 ,因此文章通过在位红外光谱方法研究了尼龙 6 /氯化钙复合材料中与氢键相关的胺基、酰胺Ⅰ带和酰胺Ⅱ带随温度及氯化钙含量的变化情况 ,证实了钙离子能通过与尼龙 6分子链上的羰基发生配位作用 ,插入尼龙 6分子链 ,破坏尼龙 6的氢键 ,降低了尼龙 6分子链的规整排列 ,使尼龙 6的结晶度减小 ,最终使尼龙 6由结晶态转变为无定形态     

金属阳离子与β-肽骨架相互作用的振动光谱特征

盐溶液中,金属阳离子(如Na+和Mg2+等)与肽分子骨架的相互作用,在酰胺基团的振动光谱中能得到体现。本工作利用红外光谱实验、分子动力学模拟和量化计算方法,以酰胺-Ⅰ带和酰胺-Ⅱ带为探针,研究了上述金属阳离子与?-肽模型分子-氮乙基丙酰胺(N-ethylpropionamide,NEPA)分子骨架的作用。研究表明在盐溶液中,阳离子/阴离子/水分子之间形成复合物。作为阳离子配体的水分子与NEPA中的羰基氧之间存在动态相互作用,从而使得酰胺-Ⅰ带和酰胺-Ⅱ带的光谱发生劈裂。我们也讨论了酰胺NH与水合离子团簇的相互作用。     

聚乙烯吡咯烷酮与苯磺酸铕相互作用研究

用变温红外光谱法和荧光光谱法研究了聚乙烯吡咯烷酮与苯磺酸铕的相互作用。聚乙烯吡咯烷酮的酰胺基团可与苯磺酸铕中的铕离子发生络合配位作用,导致聚乙烯吡咯烷酮的酰胺Ⅰ带发生红移。这种络合配位作用,使原本不溶于氯仿的苯磺酸铕可溶于含聚乙烯吡咯烷酮的氯仿溶液。在苯磺酸铕固体的发射光谱中,只能观察到铕离子的f—f跃迁特征发射峰,而在苯磺酸铕浓水溶液的荧光光谱中,亦可观测到苯磺酸根的π*→π跃迁峰,说明苯磺酸铕在水溶液中存在解络合现象。苯磺酸铕在溶液中的解络合行为使铕离子周围的可配位空间增大,这为PVP的酰胺基团与铕离子发生络合配位作用创造了条件。     

含酰胺基团稀土配合物的红外光谱

本文合成了未见文献报道的氯化稀土丙酰胺配合物,剖析了ＬｎＣｌ３．３ＰＡ和聚（苯乙烯－丙烯酰胺）负载氯化稀土配合物（ＳＡＡ．ＬｎＣｌ３）的红外光谱和电子能谱,结果表明,含酰胺基团的配体均通过羰基氧与稀土离子配位。     

光谱法研究MC尼龙6/芳纶复合材料的结构

将经甲苯二异氰酸酯(TDI)和己内酰胺改性的Kevlar纤维作为MC尼龙6的增强体,X射线光电子能谱观察到改性后纤维表面C,N和O元素的含量发生了改变,谱峰也相应发生变化。从红外光谱分析发现,Kevlar纤维和MC尼龙6相混所得谱图只是二者红外谱图的简单叠加,而改性Kevlar纤维可作为己内酰胺阴离子开环聚合的活性中心,且接枝链上的酰胺基可以与基体尼龙形成较强的氢键,有利于提高界面结合。XRD测试表明Kevlar纤维的引入并没有明显改变MC尼龙6的晶型,但其晶粒将具有更严格的三维周期性结构。在相同纤维用量时,改性Kevlar纤维增强的MC尼龙6的晶粒较未改性纤维的完善。当纤维含量小于2%时,纤维的加入有利于生成完善的α球晶,纤维含量大于2%时,α球晶结构含量随着纤维用量的增多反而下降。     

N-十六烷基聚己内酰胺的红外光谱研究

以聚己内酰胺(PA6)和1-溴正十六烷为原料,利用N-烷基化方法制备了具有不同烷基取代度的N-十六烷基聚己内酰胺(PA6C16)。采用DSC和FTIR方法研究了具有不同烷基取代度的PA6C16的热转变行为。DSC结果表明N-十六烷基聚己内酰胺的十六烷基侧链可以结晶,且低取代度的N-十六烷基聚己内酰胺(PA6C16-L)侧链结晶的熔点高于高取代度的N-十六烷基聚己内酰胺(PA6C16-H)。红外光谱结果表明,PA6C16-L侧链的亚甲基呈正交晶堆积,而PA6C16-H的侧链亚甲基则呈六方晶堆积。变温红外光谱结果显示,伴随着侧链结晶的熔融,PA6C16-H的主链构象发生明显改变,而PA6C16-L主链的构象则未显示出明显改变。     

不同体系下氢键对聚丙烯酰胺光谱的影响

采用红外,紫外光谱分析不同体系下氢键对部分水解高分子聚丙烯酰胺光谱的影响。研究表明,高分子聚丙烯酰胺中的酰胺基与部分水解的羧酸基能形成分子内氢键导致酰胺基中游离-NH₂特征吸收峰向低频方向移动;聚丙烯酰胺在水溶液中随浓度的增大主要形成分子内氢键使最大吸收波长发生红移;在含中等浓度钠离子和钙离子的水溶液体系下,分子内氢键和分子间氢键同时存在,在含高浓度钠离子和钙离子体系下,则主要形成分子间氢键。不同体系下,氢键对聚丙烯酰胺光谱的影响不同：在水溶液体系下,其最大吸收波长红移8 nm,在钠离子单独存在的体系下,最大吸收波长红移4 nm,在钙离子和钠离子同时存在的体系下,最大吸收波长红移2 nm。     

胶原调制磷酸钙矿化成核位点的红外光谱研究

对胶原、胶原 /CaCl2 、胶原 /羟基磷灰石等几种体系的红外光谱进行了比较研究。发现胶原矿化后 ,红外光谱中胶原的酰胺Ⅰ ,Ⅱ ,Ⅲ带的吸收强度显著降低 ,Ⅱ ,Ⅲ带接近消失 ,Ⅰ带发生红移现象。提出胶原中的羧基 (COOH )、羰基 (CO )为胶原矿化的两类成核位点 ,钙盐在成核位点上结晶。脱钙胶原(胶原 /羟基磷灰石经盐酸处理 )的红外光谱与纯胶原相似 ,酰胺Ⅰ ,Ⅱ ,Ⅲ带的吸收强度恢复正常 ,表明 :钙盐对胶原中酰胺基的影响是由于钙盐在该成核位点上结晶而导致的“包裹”作用。根据酰胺 3个吸收带的不同振动方式 ,用“包裹”作用解释了胶原 /钙盐复合物中 ,酰胺Ⅰ与Ⅱ ,Ⅲ带的降低程度不同的原因。分析了胶原 /磷酸钙生物矿化的作用机制。     

N-异丙基丙烯酰胺水凝胶的红外光谱

合成了聚N-异丙基丙烯酰胺(poly(N-isopropylacrylamide,PNIPAM),并利用傅立叶变换红外光谱方法,对N-异丙基丙烯酰胺及其聚态在溶液相的构象进行了表征。发现在异丙醇中N-异丙基丙烯酰胺单体结构并不存在,而是以二聚体的形式存在。而所形成的PNIPAM聚集体,其酰胺基团的典型光谱峰-酰胺-Ⅰ带的红外光谱具有无规则卷曲的特征。这些工作,在理解特异化学基团在PNIPAM中引入后的结构,在原位表征PNIPAM水凝胶体系的动态功能结构等方面打下了基础。     

尼龙6在高压退火中的晶体生长

 利用六面顶压机制备了高压退火的尼龙6样品,通过宽角X射线衍射（WAXD）、差示扫描量热（DSC）和红外光谱等手段,探索了高压退火对尼龙6结晶度以及晶体结构的变化。研究发现,在高压退火过程中尼龙6分子链段运动受到压力的限制,材料中晶体的形成主要依靠转氨基反应实现。     

磷酸-氨水蒸沉γ晶型聚酰胺6的热行为研究

尼龙6是一种多晶型的半结晶高聚物。实验采用蒸沉法制备出尼龙6,首先通过XRD和FTIR的手段进行表征,与采用沸水处理的尼龙6样品表征结果对比,确定其为γ晶型,然后在130～211℃的温度范围内进行热处理,通过DSC研究其在低于熔点热处理时的整个热行为变化过程,并运用FTIR观察其在不同条件下热处理发生的晶型变化。发现蒸沉法制备的γ晶型尼龙6随着热处理温度的升高,整体结晶完善度以及晶片厚度随着处理温度的升高而增加。而且在这个过程中,样品厚度不同的晶片在不同温度下发生了γ晶型向α晶型的转化,最终在接近熔点(211℃)热处理时,样品变为以α晶型为主。     

PVP对Nylon 6形貌及结晶行为影响的研究

采用变温红外光谱、示差扫描量热（DSC）和偏光显微镜（POM）等方法研究了聚乙烯吡咯烷酮（PVP）与尼龙6（nylon 6）分子间的相互作用及其对nylon 6热行为及结晶形貌的影响。DSC结果表明PVP的加入明显影响了nylon 6的熔融和结晶行为：随着PVP含量增加,PVP/nylon 6共混物的结晶温度、熔融温度及结晶度均逐渐降低;POM观察显示：随着PVP含量增多,nylon 6的球晶尺寸变小、球晶逐渐变得不完善。变温红外光谱结果表明,无定形PVP分子的羰基能够与nylon 6分子的N—H基团形成新的氢键,部分破坏了nylon 6分子之间的氢键结构,从而阻碍了nylon 6分子的规整排列,使其结晶度降低并导致nylon 6结晶形貌的变化。     

Miscibility studies of poly-p-phenylene terephthalamide/polyamide molecular composites

Miscibility characteristics of poly-p-phenylene terephthalamide (PPTA) with nylon 6, nylon 66, nylon 11, and nylon 12 have been examined by means of differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). Mixtures of PPTA/nylon 6, 66, 11, and 12 and amorphous nylon were prepared by coagulation in water from isotropic sulfuric acid solutions. The WAXD investigation shows the presence of small amounts of disordered crystals in the regenerated pure PPTA and to a lesser amount in the blends of PPTA/amorphous nylon or PPTA/aliphatic crystalline nylons. DSC studies show the melting point depression of nylon crystals. At low PPTA contents, a small melting point elevation occurs in nylon 6, presumably due to nucleation. The Flory-Huggins interaction parameter (χ) was subsequently calculated from the melting point depression of the nylons.     

Photoluminescence, FTIR and X-ray diffraction studies on undoped and Al-doped ZnO thin films grown on polycrystalline α-alumina substrates by ultrasonic spray pyrolysis

Undoped and aluminum-doped zinc oxide (ZnO) thin films have been grown on polycrystalline α-alumina substrates by ultrasonic spray pyrolysis (USP) technique using zinc acetate dihydrate and aluminum chloride hexahydrate (Al source) dissolved in methanol, ethanol and deionized water. A number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) were used to characterize the obtained ZnO thin films. It was seen that the orientation changed with increase in substrate temperature. During the ZnO deposition Zn source reacted with polycrystalline α-Al₂O₃ substrate to form an intermediate ZnAl₂O₄ spinel layer. It has been interestingly found that the intensity of green emission at 2.48 eV remarkably increased when the obtained ZnO:Al films were deposited at 380 °C. The FTIR absorbance intensity of spectroscopic band at 447±6 cm⁻¹ is very sensitive to oxygen sublattice disorder resulting from non-stoichiometry, which is consistent with the result of PL characterization.     

Synthesis of SnO2/ZnO composite nanofibers by electrospinning method and study of its ethanol sensing properties

In this paper, we report the synthesis of SnO₂/ZnO composite nanofibers via electrospinning method. Polyvinyl alcohol (PVA)/zinc acetate/stannous chloride nanofibers were electrospun using a solution containing PVA, zinc acetate and stannous chloride in distilled-water followed by calcination at 650 °C for 2 h, obtaining the related composite nanofibers. The nanofibers were characterized by simultaneous thermal analysis (STA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier Transform Infrared spectroscopy (FTIR). Ethanol sensing of the nanofibers showed a good and desirable sensing behavior such as high sensitivity, quick response and recovery times.     

Preparation and XPS study of X-ray photochromic transparent BiOI/nylon11 composite film

Nylon11 film immersed in BiI₃–ethanol solution was used for in situ generation of transparent BiOI/nylon11 X-ray photochromic composite materials via integration of the hydrolyzate (BiOI) of BiI₃ into nylon11. The obtained BiOI/nylon11 composite film shows a reversible photochromic effect, changing the color from orange-red to brownish black under soft X-ray irradiation and back to orange-red after air exposure. X-ray photoelectron spectroscopy (XPS) results show that the oxidation state of Bi atoms in BiOI/nylon11 composite film does not change before and after changing the color. Angle-resolved XPS analysis reveals that BiOI in nylon11 film is well distributed within an infiltration depth of about 10 nm. The source of the X-ray photochromic effect for transparent BiOI/nylon11 composite film may be related to oxygen as well as the interaction between BiOI and the amide groups. The oxygen AT% in the composite film decreases with increasing X-ray irradiation time. The present method for preparing transparent BiOI/nylon11 X-ray photochromic composite materials is facile and low cost. The X-ray photochromic effect has potential applications in some technology fields. For example, it can be used to create temporary patterning in a colored composite material surface.     

Morphology,Structure, and Crystallization of LaCl Modified Hollow Glass Microspheres/ Poly(vinylidenefluoride) Composites

Poly(vinylidene fluoride)/hollow glass microspheres (PVDF/HGMs) composites were prepared by using lanthanum chloride surface modified HGMs. The morphology, structure, and crystallization of the PVDF/HGMs composites were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), respectively. The results showed that the interaction between the HGMs and the PVDF was improved by lanthanum chloride modification. The crystal structure of the PVDF was not changed by the HGMs, but the crystallinity was decreased. In addition, the Jeziorny and the Mo methods were used to analyze the non-isothermal crystallization kinetics. The results showed that the HGMs decreased the crystallization rates and extended the crystallization time of the PVDF.     

碳酸钙在水溶性甲壳素溶液中的结晶行为

依据生物矿化基本原理,以甲壳素作为有机基质,探讨了在不同浓度甲壳素溶液中CaCO3晶体的生长情况;同时研究了生长体系的pH值和温度对生成CaCO₃晶体的影响。通过傅里叶红外光谱、扫描电子显微镜进行表征的结果表明,甲壳素溶液中形成的CaCO₃晶体完全不同于纯水中形成的晶体;而且甲壳素溶液的浓度不同,形成的CaCO₃晶体的晶型也有较大差别。在CaCO₃结晶过程中,CaCO₃对甲壳素也有影响,即晶体与甲壳素之间存在相互作用。