Synthesis of Ladder-like Polyphenylsilsesquioxanes with Fairly High Regularity Using 1,2-Ethylenediamine as Endo-template

Ladder-like polyphenylsilsesquioxanes with fairly high regularity were synthesized using an endo-template 1,2-ethylenediamine at mild temperature via direct co-hydrolysis and condensation reactions in the presence of acid catalysts in the mixture of 1,4-dioxane/H20. The features for synthesis of ladder-like polyphenylsilsesquioxanes were investigated in detail. The products obtained were characterized by FTIR, SEC, XRD and NMR.

降解检材STR分型Ladder-Like条带形成原因的探讨

目的探讨降解DNA短串联重复序列PCR扩增产物在PAGE中Ladder-L ike条带的形成原因。方法用一组人工合成的不同长度的D8S1179DNA单链,模拟降解检材中的断裂DNA;利用John M设计的D8S1179引物对模拟模板的DNA单链进行PCR扩增,PAGE分离。结果不同模拟模板的DNA单链的组合可以扩增出不同的Lad-der-L ike条带。结论短串联重复序列Ladder-like条带是PCR过程中降解DNA多态区互补扩增的产物。

STUDY ON PYROLYSIS OF POLYPHENYLSILSESQUIOXANE

X-ray photoelectron spectroscopy and Raman spectroscopy were' used to determine the chemical change of polyphenylsilsesquioxane (PPSQ) during pyrolysis in flowing nitrogen. Two temperature ranges were found for pyrolysed PPSQ below and above 600degreesC, respectively. The former is related to the rearrangement of PPSQ backbone and the latter reflects that most of backbone structure of PPSQ might be broken down and unorganized. Carbon formed in carbonization of PPSQ sample pyrolysed at 900degreesC should be sp(3) bonded carbon with crystallite size effects or defects.

SYNTHESIS AND CHARACTERIZATION OF A NOVEL REACTIVE LADDER-LIKE POLYSILSESQUIOXANE WITH LATERAL BROMOPHENYL GROUPS

A novel soluble, reactive ladder-like polysilsesquioxane (L) with lateral bromophenyl groups was synthesized successfully by stepwise coupling polymerization (SCP) method including preaminolysis, hydrolysis and polycondensation steps. The monomer 3-trichlorosilylpropoxy-4-bromobenzene (M) was first prepared via hydrosilylation reaction catalyzed by dicyclopentadienylplatinum dichloride (Cp2PtCl2). The title polymer (L) was characterized by 1H-NMR, 29Si-NMR, FTIR, X-ray diffraction (XRD), DSC and vapor pressure osmometry (VPO). The experimental results indicate that the polymer (L) possesses a typical ladder-like structure.

Synthesis and Crystal Structure of a Novel Double Ladder-like Cadmium Coordination Polymer Constructed by Isophthalate and Imidazole

A novel double ladder-like cadmium coordination polymer with isophthalate as bridging ligands and imidazole as non-chelating capping ligands was obtained by a hydrothermal reaction. The crystal is of triclinic, space group P1 with a = 10.266（2）, b = 11.573（2）, c = 12.651（3） A, α = 89.95（3）, β= 74.64（3）,γ = 68.54（3）°, C50H44Cd4N12O18, Mr = 1550.57, V= 1341.1（5）A3, Dc = 1.920 g/cm3, F（000） = 764, p = 1.651 cm-1 and Z = 1. The final refinement gave R = 0.0342 and wR = 0.0738 for 5925 observed reflections with I 〉 2σ（I）. The crystal structure involves two different ladder-like chains, which are further connected to form a ladder-like double chain architecture via hydrogen bonding interactions, extending along the b axis. The weak interactions including hydrogen bonds and π-π staking interactions contribute to the alignment of the complex in the crystalline state.

Synthesis and Structure of a Ladder-like Co-crystal Cu^ICl with 3,5-Dipropyl-4-amino-1,2,4-triazole

Redox reaction of a mixture of CuC12·2H2O, HaPO3 and dpatrz （3,5-dipropyl- 4-amino-1,2,4-triazole） at room temperature yields one new compound, [Cu（1）（/.t2-dpatrz）aCu（1）CI2], with two independent cis- and trans-propyl side chain molecules. Compound 1 crystallizes in monoclinic, space group P21/c with a = 7.474（1）, b = 17.807（1）, c = 18.851（1） A, β = 108.32（1）°, V = 2381.7（2） A3, Z = 4, C16H32CI2Cu2Ns, Mr = 534.48, Dc = 1.491 g.cm-3,μ = 2.03 mm-1, F（000） = 1104, GOOF = 1.050, the final R = 0.0445 and wR = 0.1162 for 3162 observed reflections （I 〉 2σ（I））. Compound 1 shows discrete dimeric structures （A and B） containing inversion centers and the Cu（l） ions are coordinated in triangle geometries. The isomers are connected by N-H…CI hydrogen bonds, chains with graph-set C（7） and rings R22（14） and C-H..＇Jr interactions into stair-step chains （Tapes A and B） running parallel to the [01-1] direction. The N-H…C1 hydrogen bonds result in chain and cyclic structures with graph-sets C22（17） and R34（18） linking tapes A and B to form two-dimensional networks along the [031] direction. Packing of crystal 1 is stabilized by rings R34（18） and weak C-H…C1 hydrogen bonds parallel to the [01-2] direction. Bond valence sum （BVS） and UV-Vis absorption spectra support the existence of Cu（I） ions. Compound 1 exhibits extensive green blue phosphorescence in the solid state at room temperature.

EFFECT OF POLYMERIZATION CONDITIONS ON THE LADDERLIKE STRUCTURE OF POLYPHENYLSILSESQUIOXANE

The ladderlike structure of PPSQ synthesized by-using four kinds of catalysts (MgF2, LiF, KOH and DCC) at different polymerization conditions has been investigated by IR and NMR. In the system using MgF2 as the main catalyst, the most important factor which affects the ladderlike structure of PPSQ is the composition of the dual catalysts, MgF2 and DCC. PPSQ prepared by using KOH as the catalyst has the highest regularity of ladderlike structure among all samples. PPSQ with different degree of ladder regularity can be obtained by choice of polymerization conditions.

Preparation and Characterization of Ordered Ladder Like Polyphenylsilsesquioxane via Two-step Sol-gel Method

Soluble and ordered ladder like polyphenylsilsesquioxane was synthesized by a two-step sol-gel method including hydrolysis and polycondensation. The procedure was monitored by Fourier transform infrared spectroscopy and the presence of the ladder like structure was confirmed by X-ray techniques. 29Si NMR analysis shows a very narrow half peak width（δ4） at δ –78.866 of the main chain unit C6H5SiO3/2 of polyphenylsilsesquioxane, indicating that the polyphenylsilsesquioxane has ordered ladder like structures rather than the branched ones. The relationship between molecular weight and the time of polycondensation was also discussed.

TEMPERATURE DEPENDENCE OF THE FLUORESCENCE SPECTRA OF LADDERLIKE POLYPHENYLSILSESQUIOXANE AND LADDERLIKE 1,4-PHENYLENE-BRIDGED POLYVINYLSILOXANE

Fluorescence spectra of ladderlike polyphenylsilsesquioxane (LPPS) and ladderlike 1,4-phenylene-bridged polyvinylsiloxane (LPPVS) have been measured as a function of temperature (4-55 degreesC), in dilute tetrahydrofuran solution. The excimer (IF) to monomer (I-M) intensity ratio (I-E/I-M) of LPPS dilute solution shows a double linear Arrhenius plot with a break point ascribable to a transition temperature Tt. This behavior has not been found for single chain polyorganosiloxanes. When In/(E) of LPPS was plotted against 1/T, it also gave a double linear plot with one break point, which was found in single chain polyorganosiloxanes. The different behaviors between LPPS and single chain polyorganosiloxanes may be mainly attributed to the relatively rigid double-chain macromolecular backbone of LPPS. However, the 1n(I-E/I-M) of dilute LPPVS solution versus 1/T shows a simple linear variation with a positive slope which confirms our proposition. The difference between the fluorescence results of LPPS and those of LPPVS may possibly derive from their structure differences and cooperative motion in backbone chain bonds.

SYNTHESIS AND CHARACERIZATION OF LADDER-LIKE POLYDECYLSILSESQUIOXANE

Ladder-like polydecylsilsesquioxane (LPDS) was synthesized by a preamminolysis reaction ofdecyltrichlorosilane with ethylene diamine, followed by hydrolysis and polycondensation reaction. LPDS issoluble in a nonpolar solvent such as heptane and insoluble in a high polar solvent such as methanol. It wascharaterized by IR, ~1H-NMR, ^(29)Si-NMR, GPC and X-ray diffraction.

Synthesis and characterization of a ladder-like structure compound formed by cadmium (II) and anionic nitronyl nitroxide

A ladder-like structure compound formed by cadmium (II) and anionic nitronyl nitroxide, [Cd2(NITpBA)4(H2O)4] (where NITpBA = 2-(4-carboxyphenyl)4,4,5,5-tetramethyl-4,5-dihydro-imidazol-1-oxyl-3-oxide), has been synthesized and characterized. X-ray analysis reveals that the compound 1 crystallizes in the monoclinic P21/c (No. 14) space group, and [Cd2(NITpBA)4(H2O)4] units are linked into infinite chains by radical bridging ligands.

梯形聚苯基倍半硅氧烷的合成及对RTV硅橡胶性能的影响

选取苯基三甲氧基硅烷(PTMS)作为原料,在碱性条件下通过水解缩聚反应合成了梯形聚苯基倍半硅氧烷(LPPSQ),将其作为交联剂加入生胶中,交联固化后得到了LPPSQ改性的室温硫化(RTV)硅橡胶。通过红外光谱,固态核磁硅谱以及X射线衍射图谱对产物进行表征,结果表明成功合成了LPPSQ。探究了LPPSQ的加入对RTV硅橡胶性能的影响,结果表明LPPSQ的加入能显著提升RTV硅橡胶的热稳定性能和力学性能。相比于传统RTV硅橡胶,以LPPSQ为交联剂的RTV硅橡胶断裂伸长率达到358%,提高了2倍多,韧性也得到了显著增强。此外,在热稳定性能方面,LPPSQ的加入也大幅提高了RTV硅橡胶的T10%(硅橡胶质量损失10%的温度)的Tmax(硅橡胶最大热失重速率对应的温度),分别提高了138.2℃和224.1℃。

聚倍半硅氧烷的研究现状和发展趋势

对聚倍半硅氧烷 ,尤其是聚苯基倍半硅氧烷、聚甲基倍半硅氧烷的合成、性质和应用进行了综述 ,并评述了它们的发展趋势。

梯形聚苯基倍半硅氧烷的新型制备方法

以苯基三氯硅烷为原料,利用经过改良的热平衡缩合法,得到产物梯形聚苯基倍半硅氧烷(Ph-T)。借助傅立叶红外、X射线衍射和核磁共振硅谱等方法,确定了产物具有规整的梯形分子结构;以热重分析测定了其耐热性,在空气中失重5%时温度为530℃,具有优良的耐热性能。

两组引物对无毛囊毛根的PCR-STR分型

目的了解无毛囊毛根的短扩增子引物和通用引物PCR-STR分型在法医实践中应用的可行性。方法应用5对Bulter设计的短扩增子引物D8S1179、D21S11、THO1、D16S539和VWA与其对应的STR通用引物,利用非变性PAGE,对无毛囊毛根进行PCR-STR分型的对比研究。结果短扩增子引物与通用引物对无毛囊毛根分型的正确率:D8S1179为11.4%和17.1%、D21S11为3.7%和5.9%、vWA为22.2%和33.3%、THO1为9.3%和5.6%、D16S539为0和9.2%。毛根的短扩增子引物和通用引物部分STR分型出现了干扰结果的Ladder-like背景条带。结论在对无毛囊毛根检材进行通用引物和短扩增子引物PCR-STR分型时,五个STR位点分型检测的成功率有限,还需注意Ladder-like条带的干扰。

硅倍半氧烷改性聚酰亚胺(PI/Si)复合膜性能

通过在聚酰亚胺(PI)中分别添加笼型八氨基苯基硅倍半氧烷(OAPS)、笼型八苯基硅倍半氧烷(OPS)、梯形聚苯基硅倍半氧烷(PPSQ)和无机纳米SiO2,制备了4种含硅聚酰亚胺(PI/Si)复合膜.对PI/Si复合膜的相容性、力学性能、热性能和阻燃性能进行了研究.结果表明,OAPS与PI间展现出较好的相容性,PPSQ次之,而OPS,SiO2与PI的相容性较差;但相容性与复合膜的力学和热性能无明显的对应关系.SiO2可提高PI的力学性能;PI/OAPS复合膜的T g最高;OAPS,PPSQ或SiO2的加入使PI复合膜的热稳定性稍有提高,而少量OPS的加入大大降低PI膜的热稳定性.这类PI/Si复合膜的显著特点是能够大幅提高PI膜的极限氧指数,含硅化合物能够增加PI燃烧后残炭量,使残炭的形貌得到显著改善.PI/Si复合膜在燃烧过程中在表面形成一层白色含硅包裹层,起到隔热隔氧及保护内层有机物不被燃烧的作用.硅倍半氧烷对炭层形貌的改善显著,展现出比SiO2更好的阻燃性能.

利用光学显微镜研究溶剂诱导的梯形苯基聚倍半硅氧烷结晶(英文)

通过溶剂诱导结晶的方法研究了梯形苯基聚倍半硅氧烷(PPSQ)的球晶结构. 采用光学显微镜研究了溶液的浓度、溶剂的挥发时间以及温度等影响因素对梯形苯基聚倍半硅氧烷的球晶结构形貌的影响. 实验结果表明:稀释溶液浓度与提高结晶温度在改变球晶的形态方面具有相同的效果. 球晶的尺寸会随着溶液浓度的降低或者结晶温度的升高而增加. 这都归因于梯形苯基聚倍半硅氧烷在二甲苯中的溶解度的增加. 在不改变其它结晶条件的情况下,延长溶剂的挥发时间也会形成更大的球晶. 当在光学显微镜下旋转样品时球晶的结构不会发生改变,这表明球晶具有均一的晶体学取向结构. 负性球晶的特征也表明梯形苯基聚倍半硅氧烷的分子链是沿着球晶的切线方向排列. 考虑到梯形苯基聚倍半硅氧烷具有刚性的分子链,还提出了梯形苯基聚倍半硅氧烷可能的球晶结构模型.

色谱用金属柱管的脱活研究

利用苯基三乙氧基硅烷的酸催化水解缩合反应合成了具有梯形结构的聚苯基硅倍半氧烷预聚体 ,再以其2 0 %～ 30 %的丙酮溶液对气相色谱用金属柱管进行遮盖性脱活 .预聚体涂层经溶剂挥发高温老化处理后获得了能耐 4 0 0℃高温的脱活涂层 .以甲醇、乙醇、异丙醇、叔丁醇为测试物 ,内径 2mm、长 3.0m、固定相为PorapackQ的填充聚四氟乙烯柱为预分离柱串接测试柱的方法对该涂层进行了评价 .结果表明 ,经该涂层处理的不锈钢柱管在115℃时对低级醇的吸附活性与PorapackQ柱的活性相近 ,活性明显降低 .涂层结构中含有的苯环和羟基等官能基 。

聚苯基倍半硅氧烷研究进展

分别介绍了梯型、笼形聚苯基倍半硅氧烷及其共聚物的结构、性质和合成方法,重点综述了苯基倍半硅氧烷共聚物研究进展,并对苯基倍半硅氧烷材料的发展趋势进行了展望。

环梯形聚苯基硅倍半氧烷的硝化研究

为了提高环梯形聚苯基硅倍半氧烷(Cyclic Ladder Polyphenylsilsesquioxane,CL-PPSQ)在聚合物中的相容性,使用多种硝化试剂,包括发烟硝酸、HNO_3-H_2SO_4、KNO_3-H_2SO_4、HNO_3-KNO_3、CH_3COOH-KNO_3、(CH_3CO)_2O-HNO_3,在不同的条件下对其进行硝化,制备得到含硝基基团的NO_2-PPSQ。使用FTIR、元素分析、GPC、TGA、~1 H NMR等对硝化产物进行表征。结果表明:发烟硝酸、HNO_3-H_2SO_4、KNO_3-H_2SO_4对CL-PPSQ的硝化能力最强,产物中硝基数目最多,但产物分子量降低,硅氧烷链段发生断裂;而HNO_3-KNO_3和CH_3COOH-KNO_3对CL-PPSQ没有硝化能力;(CH_3CO)_2O-HNO_3硝化过程温和,硝化能力适中,制备得到分子链不断裂的硝化产物。对不同硝化试剂的硝化机理进行了分析,在发烟硝酸、HNO_3-H_2SO_4、KNO_3-H_2SO_4体系中,NO_2^+为硝化活化剂;对于(CH_3CO)_2O-HNO_3体系,CH_3COONO_2为主要的硝化活化剂。