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     

Cd_xHg_(1-x)Te混晶的远红外反射光谱和多振子模型

在温度4.2—300K和波数15—450cm~(-1)范围内研究了x=0.18到0.45的不同组份的Cd_xHg_(1-x)Te样品的远红外反射光谱。实验观察到了类CdTe光学声子反射带的精细结构和低组份样品类HgTe反射带的复杂结构,研究了这些结构对组份和温度的关系,并用多振子模型讨论了反射光谱的这种精细结构。 对实验反射光谱用经典的振子匹配方法进行了拟合计算,并从这种拟合运算获得了Cd_(x~-)Hg_(1-x)Te的远红外介电函数谱及其它光学常数和频率的关系。     

CdxHg1-xTe混晶的远红外反射光谱和多振子模型

在温度4.2—300K和波数15—450cm^-1范围内研究了x=0.18到0.45的不同组份的Cd_xHg_1-xTe样品的远红外反射光谱。实验观察到了类CdTe光学声子反射带的精细结构和低组份样品类HgTe反射带的复杂结构,研究了这些结构对组份和温度的关系,并用多振子模型讨论了反射光谱的这种精细结构。对实验反射光谱用经典的振子匹配方法进行了拟合计算,并从这种拟合运算获得了Cd_(x^-)Hg_1-xTe的远红外介电函数谱及其它光学常数和频率的关系。 关键词：     

取代金属(铁、锰、钴、铜、锌)卟啉的光谱分析

对系列取代金属(铁、锰、钴、铜、锌)卟啉化合物的紫外光谱、红外光谱、远红外光谱进行了详尽的测试和分析,揭示了不同结构金属卟啉的光谱规律,从理论上分析了形成光谱规律的原因。针对目前氯化铁卟啉轴向Fe—Cl键远红外表征的报道结果不一致性,采用理论分析与实验测定相结合的方法,探索了氯化铁卟啉中Fe—Cl键远红外吸收规律。研究结果表明：Fe—Cl键的振动吸收频率不是固定不变的,而是与卟啉环的结构有关,且和Fe—Cl的键长呈线性关系。     

1,4-萘醌的太赫兹,远红外及低频拉曼光谱研究

本文对1,4-萘醌进行了太赫兹时域光谱,远红外吸收光谱及低频拉曼散射谱的测试研究。1,4-萘醌的太赫兹吸收光谱与远红外谱仪测得的光谱取得了在1.75 THz(58.3 cm-1)/1.63 THz(54.3 cm-1)等处吸收峰位基本相同、两者相互佐证和补充的结果。将太赫兹和远红外吸收谱与低频拉曼散射谱进行比较,表明两种选择机制不同的光谱在1.04,1.72和4.59 THz等处的峰位基本重合,结合群论的不可约表示理论分析,表明该样品在低频波段具有拉曼活性和红外活性的振动属性(A1、B1或B2)。采用Gaussi-an03软件的密度泛函理论B3LYP函数和6-311基组模拟单分子红外与拉曼光谱,结合实验分析,对部分分子基团或原子振转模式给与了指认。     

阻燃尼龙1010的研究

本文系统的研究了尼龙1010阻燃体系。确定了阻燃尼龙1010最佳配方。采用复合阻燃剂体系，在保证尼龙1010具有良好的阻燃性能前提下，可大大减少阻燃剂的加入量，从而减少由于阻燃剂的加入而引起的原尼龙1010树脂抗张强度的降低。     

基于太赫兹谱分析中药材鉴别

中草药分析与鉴定对中草药质量控制意义重大,以飞秒激光为基础的太赫兹时域光谱技术(THz-TDS)是一种新型相干远红外光谱测量技术。为了研究基于太赫兹谱的中药材鉴别可行性,应用THz-TDS研究了室温下黄芪、当归、杜仲及三种掺杂的黄芪在0.2~2.2 THz范围内的光学特性,得到了对应的时域谱、频域谱和吸收谱。结果表明在此波段三种中草药的时域谱、频域谱及吸收谱存在显著差异;三种掺杂黄芪的频域谱、吸收谱虽相似但也有明显不同。利用太赫兹时域光谱技术鉴别中药材是可行的,它可为中草药质量控制提供一种新的方法。     

ZnO纳米颗粒中的表面态发射特性研究

研究了不同粒径ZnO纳米颗粒样品(17～300nm)的时间光谱,通过对各粒径样品时间积分光谱的谱带结构进行高斯拟合解迭,发现光子能量位于ZnO谱带低能侧的高斯拟合成份Xc3的荧光中心波长随粒径的减小而红移,同时发光带的寿命也随之缩短.基于ZnO谱带低能侧的高斯拟合峰发光带强烈依赖于ZnO样品粒径的谱带特性,提出了与ZnO禁带内的表面态能级有关,同时研究表明,表面态在尺寸降到一定程度的纳米体系中起着重要的作用.     

偏磷酸钙玻璃陶瓷的Raman光谱分析

测量了Ca/P摩尔比为0.45的偏磷酸钙玻璃及其在300~700℃下结晶化处理获得玻璃陶瓷的拉曼光谱,对谱峰的振动模式进行了指认,利用拉曼振动频率计算了P—O键长。光谱分析发现偏磷酸钙玻璃在300℃已经开始了结晶相变,不同温度下,sν(PO2)和sν(POP)谱带的振动频率基本不变,随着温度提高,谱峰强度增加,并出现了精细的指纹结构;玻璃陶瓷的表面和内部的结构不同,表面结晶化程度高于内部;结晶过程中,P—O键平均键长会发生变化,随着结晶化程度的提高,骨架上(POP)的P—O键平均键长减小,由159.96 pm变为158.27 pm,侧链(PO2)上的P—O键长增大,由147.90 pm变为149.02 pm。     

冰晶石类氟化物的红外光谱分析

用傅里叶变换红外光谱法研究了Ｋ３ＡｌＦ６，α－Ｒｂ３ＡｌＦ６，β－Ｒｂ３ＡｌＦ６和Ｃｓ３ＡｌＦ６等注晶石类氟化物的远红外及中红外光谱，并对远红外光谱和部分中红外光谱带进行了指认。     

高压下尼龙1010-单壁碳纳米管复合材料的结晶行为

 采用XKY-6×1200MN型六面顶压机,在不同温度、压力条件下处理30 min后制备了尼龙1010(PA1010)-单壁碳纳米管（SWCNT）复合材料的高压结晶样品,通过X射线衍射（XRD）、差热分析仪（DSC）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）,研究了高压处理样品的结晶行为、结构变化及形貌特征。结果表明：在1.0~2.5 GPa压力下,属于高压熔体结晶;在3.0和4.5 GPa压力下属于高压退火处理;高压结晶或高压退火均有助于聚合物片层晶体的增厚,并且高压熔体结晶的增厚效果优于高压退火处理。XRD结果表明,PA1010的三斜晶型在高压处理后保持不变,高压熔体结晶或高压退火都可以使(100)晶面和(010)晶面间距减小,即高压处理致使聚合物分子链紧密堆积。DSC结果表明：在高压熔体结晶过程中,升高压力和温度可以得到片层厚度较大的PA1010晶体;在2.0 GPa、350 ℃下获得的高压结晶样品的熔点和结晶度最高,分别达到208.5 ℃和64.6%。SEM和TEM结果表明：与常压结晶样品相比,高压结晶样品内部出现c轴厚度超过150 μm的大尺寸晶体;SWCNT与PA1010基体之间形成相互穿插的网络结构,刚性的SWCNT作为高压成核剂促进PA1010晶体生长和增厚。     

Investigation of MWS Relaxation in Nylon 1010 using Dielectric Relaxation Spectroscopy

Maxwell–Wagner–Sillars (MWS) relaxation in nylon 1010, arising from charge carriers accumulated at the interphase between amorphous and crystalline regions, has been investigated by means of dielectric relaxation spectra. In the frequency spectra of nylon 1010, dielectric permittivity showed high values at low frequencies originating from charge carrier movement. For the MWS relaxation, the dielectric strength was independent of temperature. The results revealed that there is a transition temperature, located between 110 and 120°C, resulting in the separation of two different charge carrier movement mechanisms. Below and above this transition temperature, the temperature dependence of the MWS relaxation time follows the Vogel–Tammann–Fulcher type, showing that the charge carrier transport is governed by the motion of the polymer chains. The change of charge carrier movement mechanisms is due to the onset of polymer chain motion in the interphase.     

Studies on crystalline forms of Nylon 6. III. Crystallization from the glassy state

The relative amounts of the α- and γ-crystalline forms of nylon 6 obtained from the glassy state under different crystallization conditions have been studied by the X-ray diffraction procedure described in the previous paper. The weight fraction of the γ-form decreases with increasing crystallization temperature above 160°C and that of the α-form increases. Growth of the γ-form is predominant in crystallization at 100°C and of the α-form at 200°C. Differential scanning calorimetry and density data are presented. A large amount of a thermally unstable form is included in the γ-form crystallized from the glassy state at lower crystallization temperatures and is transformed into the a-form with annealing at 200γC. Thermal stability of the γ-form obtained from the glassy state was quantitatively investigated and discussed.     

Interpretation of far-infrared absorption spectra in germanium

The high resolution far-infrared absorption spectra of free excitons in germanium are analyzed for the first time using a model which accurately includes both the anisotropy of the valence and condition bands and the degeneracy of the valence band. The observed structure is in good agreement with the calculated transitions between the anisotropy split ground state and the various p-like excited states.     

Annealing Effect on Chain Segment Motion and Charge Trapping and Detrapping in Nylon 1010

The chain segment motion and charge trapping and detrapping in nylon 1010 films were investigated by means of thermally stimulated depolarization current (TSDC). There were three current peaks (named α, ρ1, and ρ2 peaks, respectively) in the experimental TSDC spectra above room temperature. The α peak is attributed to a background dipole relaxation by the motion of chain segments and space charge contribution, the ρ1 peak is originated from a space charge trapped in the bulk amorphous regions and the interphase between crystalline and amorphous regions, the ρ2 peak is originated from space charge trapped in crystalline regions. By analyzing the characteristic parameters of these peaks, it was found that with in increase of the degree of crystallinity the activation energy of the a peak increased from 1.12 to 1.22 eV and the trap depth of the ρ2 peak increased from 2.70 to 2.82 eV, while the trap depth of the ρ1 peak decreased from 1.50 to 1.29 eV. Annealing induced a decrease of the chain segment mobility and promoted the creation of traps in nylon 1010. Annealing also decreased the stability of the trapped charges in the bulk amorphous and the interphase regions and increased the stability of the trapped charges in the crystalline regions.     

聚己内酰胺-锌盐相互作用的研究

本文用X 射线衍射和傅里叶变换红外光谱法研究了聚己内酰胺与氯化锌的相互作用。实验结果表明 ,当把聚己内酰胺的甲酸溶液加入饱和氯化锌水溶液 ,沉淀析出物与在纯水中析出的聚己内酰胺有明显的不同。X 射线衍射结果表明在纯水中沉淀析出的聚己内酰胺分子链发生结晶而在饱和氯化锌水溶液中析出的聚己内酰胺却未观察到尖锐衍射峰。红外光谱研究证明 ,在饱和氯化锌水溶液中析出的聚己内酰胺中所含的锌离子与酰胺基团发生相互作用 ,致使酰胺Ⅰ ,Ⅱ带发生巨大变化。酰胺Ⅰ带发生红移证明锌离子与酰胺基团上的羰基发生络合配位 ,这种作用抑制尼龙分子链之间通过CO和N—H基团形成氢键 ,阻碍聚己内酰胺分子的自由运动和整齐堆砌 ,从而使尼龙无法结晶。尼龙与锌盐之间的这种相互作用可能为发展一种尼龙加工制造新方法提供种新的机会。     

Infrared studies of chain folding in polymers. v. polyhexamethylene adipamide

Systematic infrared studies of a series of polyhexamethylene adipamides (nylon 66) have resulted in the assignment of two bands to the regularly folded polymer chain. Utilizing this assignment and long-period measurements by small-angle X-ray diffraction, a method has been developed to compare the amount of regular chain folding in solution-crystallized samples precipitated at different temperatures. At high supercoolings in solution, only 60% of the chain folding which occurs has a regular structure. Annealing of the solution-crystallized samples not only produced a longer fold period but also regularized the folds. Melt-crystallized samples when annealed do not show much increase in fold period or regularization of the folds. Glass-crystallized samples show a rapid initial increase with time at a particular temperature in long period and regular folding. For the glass-crystallized samples crystallized at different temperatures for the same period of time, higher temperatures of crystallization produce longer fold periods and greater fractions of regular folds. The infrared fold bands disappear when samples consisting of regular folds are deformed but reappear after annealing.     

Studies of intermolecular interactions by matrix isolation vibrational spectroscopy: Self-association of water

The mid- and far-infrared spectra of water in argon and nitrogen matrices have been reinvestigated. The water molecule rotates in an argon matrix, but in a nitrogen matrix two low-frequency bands are attributed to libration of the water monomer about its A and C rotational axes. Combinations of these modes with the stretching and bending modes of the water monomer were observed. A detailed concentration-dependence study enabled bands to be attributed to dimer, trimer, and tetramer or higher multimers. The dimer and trimer were both found to have open chain structures, whereas tetramer or higher multimer species appear to be predominantly cyclic. Intermolecular modes, observed for dimer and trimer in the far-infrared spectra, are tentatively assigned.     

Oversized helical waveguides for optically pumped far-infrared lasers

The feasibility and the theory of oversized helical waveguides for optically pumped far-infrared lasers are studied. The dispersion relation and the relevant pass bands are shown.     

Infrared studies of chain folding in polymers. X. polycaprolactam

The 1210-, 1233-, and 1288—cm^?1 infrared bands in the α form of nylon 6 are shown to result from a unique conformation in a tightly folded chain with adjacent reentry. The assignment of the 1210- and 1288-cm^?1 bands to motions of a gauche nitrogen-methylene group in the fold and the 1233-cm^?1 band to motions of a gauche carboxyl-methylene group in the fold is supported by the infrared studies of the α form of nylon 6, the γ form of nylon 6, poly-D(-)β-methyl- ? -caproamide (PBCA), and the high- and low-temperature forms of the cyclic dimer of nylon 6. The γ- form of nylon 6 and PBCA do not exhibit a unique conformation in the fold. The 1198-cm^?1 band can be assigned to the trans conformation of the amide group which exists in the normal planar zigzag conformation in the α-form crystal. A mechanism for the α to γ iodine-induced transition in nylon 6 is proposed showing the role of the fold in maintaining a minimum of molecular disordering during the transformation.