可溶性稀土聚乙炔的合成及其聚合机理的研究

研究了各种催化体系、催化剂浓度及聚合条件对催化效率(f)和聚乙炔分子量()的影响。发现Nd(i-OC_3H_7)-AlR_3(R=C_2H_5,i-C_4H_9)催化体系可获得较大的可溶分数(q)。催化剂浓度、Al/Nd克分子比和聚合温度对f、及q均有一定影响。可溶性Nd(i-OC_3H_7)_3-AlR_3催化体系的UV光谱证实、Nd的价态与AlR_3混合与AlR_3混合后保持不变。PA的IR光谱示出,Nd(i-OC_3H_7)_3-Al(C_2H_5)_3及Nd(i-OC_3H_7)_3-Al(i-C_4H_9)_3体系获得的聚合物分别含有CH_3CH_2—和(CH_3)_2CHCH_2—末端基。上述结果表明,乙炔的聚合可能是通过单体在Nd-C键之间的插入进行的。     

可溶性稀土聚乙炔的某些结构特征

本文利用UV、IR、Ramaan、ESR和X射线衍射等方法研究了可溶性聚乙炔的某些结构特征。发现非结晶的可溶性聚乙炔的光谱和波谱性质与结晶的膜状及粉末状聚乙炔有明显的差异,可能是由于它们的分子量相差悬殊造成的。实验结果表明,线型聚乙炔可能存在可溶的临界分子量,其值在=500 左右。     

苯衍生物二阶非线性光学性质的量子化学研究

本文采用引入外场微扰的CNDO/S—CI方法,计算了一系列苯衍生物的分子二阶非线性光学系数,探讨了取代基的电子性质、取代位置及取代基数目对分子二阶非线性光学系数的影响.结果表明;取代基的供电能力越强,分子的二阶非线性光学系数越大.D,A对位二取代苯和1—D,2.4—A,A三取代苯具有较高的非线性光学效应,苯衍生物中取代基数目为3时分子具有最佳的非线性光学效应.文中还对上述结论给出了初步的理论解释.     

通过等离子体表面处理提高聚乙炔稳定性

用等离子体方法对聚乙炔膜进行表面处理发现,其碘掺杂室温电导率与未处理的PA膜相当,但电导在空气中的稳定性及膜自身的抗氧化能力都有了较大提高。ESCA谱证实了在空气等离子体处理后的PA膜表面上接入了O和N原子。另外,IR光谱结果也表明,随着等离子体处理功率的增加,PA膜反式食量逐渐增加,顺式含量相应减少。     

聚乙炔的离子注入法掺杂

<正> 离子注入是一种物理摻杂方法,在半导体器件的制备中已得到广泛的应用,它与常规的化学、电化学或热扩散掺杂相比具有一些特点:可以通过质量分析器选取单一的注入离子,故掺杂杂质的纯度高;根据注入离子的剂量和能量,精确控制到掺人杂质的数量和深度等等。近年来,采用离子注入技术进行掺杂,改变聚合物或其它绝缘材料表面性质的研究已逐步引起重视真视。     

前体法制备单分散遥爪聚乙炔

合成了苯基乙烯基亚砜 (PVSO) ,并以萘 碱金属作为引发剂、丁二酸酐作为终止剂 ,进行阴离子聚合 ,制备出单分散、端羧酸盐的苯基乙烯基亚砜的遥爪聚合物 ,聚合物的功能度基本在 1 6 0以上 .在真空加热条件下 ,聚苯基乙烯基亚砜发生侧基热消除反应 ,从而获得末端为羧酸盐的遥爪聚乙炔     

红外光学材料用ZnS粉体标准物质的制备

概述红外光学材料用ZnS粉体的用途及硫酸根、游离硫杂质对其性能的影响。介绍以提纯、添加等方法进行红外光学材料用ZnS粉体标准物质制备的工艺过程。以硫化锌粉体为基础制备的6种标准物质硫酸根含量和单质硫含量在0．1％～0．5％范围呈3个梯度分布,扩展不确定度分别不大于7％和10％（k=2）。     

偶氮苯侧链结构对聚丙烯酸酯三阶非线性光学性能影响

设计合成了一系列含偶氮苯非线性生色团的丙烯酸酯,并采用溶液聚合法合成了功能化的聚丙烯酸酯,利用FTIR、NMR、UV等对化合物的结构进行了表征,证实得到了指定结构的化合物.利用Z扫描技术对合成的聚丙烯酸酯的非线性光学性能进行了研究,通过对聚合物的非线性光学吸收拟合,计算得到非线性吸收系数β和三阶非线性系数χ(3),并探讨了取代基生色团分子结构与高分子三阶非线性光学性能的关系,结果显示增大侧链生色团π电子离域长度或强DπA(推拉基团)结构均可有效提高聚合物的三阶非线性光学性能.     

氧化和硫化对聚乙炔导电性能的影响

本文采用量子化学CNDO/2晶体轨道方法,对硫化聚乙炔和氧化聚乙炔的分子结构及电子质进行了了理论计算和分析,探讨了氧化和硫化对聚乙炔导电性能的影响,揭示了硫化抑制聚乙炔氧化,从而在空气中稳定的本质。     

溶剂对聚乙炔合成及性能的影响

聚乙快的不稳定性及难以加工影响了其应用.最近,Naarmann通过陈化在硅油中的Ti(OBu)_4~-AlEt_3催化体系及加入不同量的Li-(n-Bu)制得了拉伸后电导率达10~5S/cm的聚乙炔膜,此膜的电导和形态在空气中几个月几乎不发生改变.我们曾报导用加热的甲苯-Ti(OBu)_4~--AlEt_3催化体系合成高性能聚乙炔膜.本文进一步讨论不同溶剂对高性能聚乙炔(HPPA)合成及性能的影响.     

掺杂剂锂链间迁移在聚乙炔纵向导电机制中的作用

聚乙炔(PA)的电导率X(Ω~(-1).cm~(-1))经掺杂可以在十二个数量级内变化。PA导电机理与一般的无机导体或半导体不同,PA通过荷电孤子与中性孤子之间的电子跃迁导电,而掺杂剂参与可增大这种跃迁的几率。掺杂剂与PA之间存在着相互作用,并由此而引起PA多种性质的变化。深入研究PA链间通过掺杂原子(或分子)进行的相互作用以及电荷传递过程,对于进一步揭示PA的垂直电导率产生的本质有着十分重要的意义。     

NONLINEAR OPTICAL PROPERTIES OF MOLECULAR TWINS

Three different series of twin nonlinear optic (NLO) molecules were studied, in which the two NLO chromophores are linked by a central flexible polymethylene spacer. The first series, which had two azobenzene chromophores (Azo-twins), was designed to also exhibit liquid crystallinity. Most of the members of this series exhibited a nematic mesophase. The second series had two 4-nitrophenol units as chromphores (PNP-twins), while the third one was based on 4-alkylsulfonyl-4'-alkoxy azobenzene chromophores (Sulfazo-twins). These twin NLO systems exhibited interesting odd-even oscillations in their second harmonic generation (SHG) efficiencies in the powder form. When the spacer had an odd number of methylene groups, they exhibited significantly higher powder SHG efficiency than their even counterparts, with the even ones most often exhibiting no detectable SH signal. Preliminary single crystal X-ray diffraction studies performed on the PNP-twin series showed that while the even members possess a molecular center of symmetry and pack centro-symmetrically, the odd ones do not, leading to the observed alternation. The orientational-disordering dynamics of two of the twin series – the PNP and the Sulfazo-twin series, doped in a poly(methyl methacrylate) matrix, was also studied by monitoring the SH-signal decay in electric field poled samples. Interestingly, the maximum attainable SH signal, χ⁽²⁾, in the poled samples also showed an odd-even oscillation with the odd ones again exhibiting a higher value of χ⁽²⁾. The temporal stability of the SHG intensity at 70°C, after the removal of the applied corona, was also studied and the relaxation of the chromophores was found to follow a biexponential decay. The slower relaxation component exhibits a spacer length dependence, which suggests the interplay of two factors in governing the temporal stability in such polymer doped twin systems, one is the conformational discomfort experienced by the spacer in adopting a U-shaped geometry, and the other the electrostatic repulsion when two aligned dipoles lie very close to each other.     

Third-order nonlinear optical studies of newly synthesized polyoxadiazoles containing 3,4-dialkoxythiophenes

The third-order nonlinear optical properties of newly synthesized soluble polyoxadiazoles containing 3,4-dialkoxythiophenes were investigated by using Z-scan and degenerate four-wave mixing (DFWM) techniques. The measurements were performed at 532 nm with 7 ns pulses from a Nd:YAG laser. We found a good agreement between the values of χ⁽³⁾ determined from both the experiments. Z-scan results indicate a negative nonlinear refractive index, n₂, whose magnitude is of the order of 10⁻¹⁰ esu for all the copolymers. The variation of nonlinear response among the copolymers clearly indicates the dependence of χ⁽³⁾ on donor and acceptor type of units present in these copolymers. The copolymers exhibit strong reverse saturable absorption and good optical limiting properties at 532 nm.     

Optical Nonlinearities of Phthalocyanines and Naphthalocyanines

The nonlinear absorption and refraction of soluble phthalocyanines and naphthalocyanines have been measured with z-scan technique using 8 ns, 532 nm laser pulses. The excited-state absorption cross-section and the excited-state refractive-index cross section have been estimated under the consideration of laser induced thermal effect. The excited state absorption induced n2 and Re χ⁽³⁾ values are in the range of 10^?12 esu. These observed data are enhanced by the concentrations of both metal substituted Pc's and Nc's, but this increment became very small for the metal free phthalocyanine. During the optical limiting experiments, a 25% linear transmitted solution of R₈PcH² can limit laser pulses to ≤ 120 μJ from incident energies as high as 2.0 mJ, and this limitation moved down to ≤ 50 μJ when replacing R₈PcCu from P₈PcH₂. A similar property has also been observed for the metal substituted naphthalocyanines. The results indicate that both the nonlinear refraction and optical limiting properties should be strongly affected by the metal induced triplet-state nonlinear absorption in both Pc's and Nc's. Moreover, the laser pulses created a self trapped filament inside the solution of this optical limiter, while emitting time-resolved, concentric rings on a projection screen, which could be induced by the thermal lensing effect. The various optical nonlinear properties observed from these materials should make them valuable as an optical limiter.     

碳纤维复合聚乙炔膜合成及其p-型电池的性能

聚乙炔(PA)膜作为电极材料实用化的主要困难在于稳定性较差.虽然对这一问题进行了不少研究,但至今成效不大.我们从提高聚乙炔膜的强度、导电性及整体电流分布出发,用冷等离子体方法首次合成了碳纤维复合聚乙炔膜.结构分析结果表明,在复合膜中碳纤维和聚乙炔形成了一定程度的接枝,其空气和热稳定性均高于纯PA膜.用这种膜构成的p-型电池具有较高的化学掺杂度,各项电性能均有所提高.     

PREPARATION AND SECOND-ORDER OPTICAL NONLINEARITY OF NOVEL PHENOXYSILICON NETWORKS BY SOL-GEL PROCESS**

 Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H₂O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d₃₃) of 10-?～10-8 esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120℃) indicated that these films exhibit high d33 stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks.     

OPTICAL PHASE CONJUGATION RESPONSE OF PHOTOINDUCED POLYMER FILMS CONTAINING AZOBENZENE MOIETIES WITH CHIRAL GROUP

An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy]-4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene(Ml) was synthesized. Polymer (PMl)possessing optical phase conjugated response was obtained by homopolymerzation of the optically active monomer (Ml)using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could beeasily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degeneratefour-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminarymeasurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonalsymmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiatingbeams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For thecase of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated responseintensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photo-ative material.