SYNTHESIS AND CHARACTERIZATION OF A SOLUBLE LADDERLIKE POLYSILSESQUIOXANE CONTAINING REACTIVE ESTER GROUPS*

A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for thefirst time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. Themonomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoatewith trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp_2PtCl_2) catalyst. Combination of FTIR,~1H-NMr, ~(13)C-NMR, ~(29)Si-NMR, XRD, DSC, TGA and VPO methods was used to demonstrate that the polymer obtained hasan ordered ladderlike structure. The synthesized Ester-T may have promising applications as a precursor of advanced functional polymers.     

SYNTHESES OF THE SOLUBLE,HIGH MOLECULAR WEIGHT AND LADDERLIKE POLYPH ENYLSILSESQUIOXAN E AND COPOLYMETHYLPHENYLSILSESQUIOXANES BY PREAMMINOLYSIS METHOD

Soluble, high molecular weight (MW) and ladderlike polyphenylsilsesquioxane (LPPSQ) and its copolymers, ladderlike random and block copolymethyiphenylsilsesquioxanes(LR-PMPSQ and LB-PMPSQ)have been prepared by preamminolysis, hydrolysis and polycondensation reactions. The preparation method can be carried out easily at the temperature below 95℃with high yield of 95 %, instead of the conventional way by using high-boiling solvent and any reaction activator or by precipitation with methanol. Three kinds of ladderlike polymers have been characterized. The MW's of the polymers reached to 10~6 without noticeable gelling. The scheme for synthetic route has been proposed.     

SYNTHESIS AND CHARACTERIZATION OF A NOVEL REACTIVE OLIGOMERIC LADDERLIKE COPOLYMETHYL-AMINOPROPYL SILSESQUIOXANE

A novel ordered reactive oligomeric ladderlike copolymethyl-aminopropylsilsesquioxane (Me-AP-T), was successfully synthesized by an efficient hydrosilylation graft reaction of 1,1,1-trimethyl-N-2-propenyl-silanamine with a reactive oligomeric |adderlike copolymethyl-hydrosilsesquioxane (Me-H-T), which was prepared by “supramolecular chemistry-dictated stepwise coupling polymerization” process. FT-IR, ^1H- and ^29Si-NMR spectra show that hydrosilylation reaction proceeds completely. Moreover, ^1H-NMR spectra also indicate that both the molar ratios of ≡SiMe group to Si-H and ≡SiMe group to ≡SiPrNH2 are approximately 1:1 respectively based on the ratio of integrated resonance areas of the different groups. XRD analysis and ^29Si-NMR spectra are used for investigating the ladderlike structure of the polymers. A high Tg (128.38℃) of Me-AP-T shown in DSC measurement implies that the ordered reactive Me-AP-T macromolecules have much stiff chains.     

SYNTHESIS OF NEW HIGH MOLECULAR WEIGHT AND REACTIVE LADDERLIKE POLYSILSESQUIOXANES*

Ladderlike polychloropropylsilsesquioxane (CP-T) was first synthesized by "stepwise coupling polymerization".The molecular weight of CP-T is as high as 1.7×10~5. It is a tough, elastic reactive ladderlike polymer and has good heat-resistant and adhesive properties. CP-T can further react with many nucleophilic reagents to generate new ladderlike reactivepolysilsesquioxanes, which can be used as potential precursors in the synthesis of functional ladderlike polymers.     

ARCHITECTURE OF LADDER,TUBULAR AND SIEVE-PLATE POLYMERS PREPARED BY STEPWISE COUPLING POLYMERIZATION

"Stepwise-coupling polymerization" (SCP) is a very useful approach for preparing microstructure-controllableordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular polymers (TP), and two-dimensional sieve-plate polymers. The novel reactive LPs are important precursors of micro-structure controllable polymerssuch as "fishbone-" or "rowboat-"like mesomorphic polymers and their metal complexes as well as tubular polymers (TPs).They are full of great potential for use as advanced materials.     

SYNTHESIS OF LADDERLIKE POLYHYDROXYPROPYLSILSESQUIOXANE

Ladderlike polyhydroxypropylsilsesquioxane (HO-T) was synthesized by alcoholysis of ladderlike poly(3-propionyloxy-propyl)silsesquioxane. The HO-T was characterized by GPC, IR, NMR, DSC, TGA and X-ray diffractionmethods. Through hydrogen-bonding interaction, ladderlike polymer (HO-T) can form a supramolecular complex withsomewhat regular structure.     

Surface study of ladderlike polyepoxysiloxanes

By using the two‐liquid geometric method and the three‐liquid acid‐base method, we are the first to determine the surface tensions of ladderlike polyepoxysiloxanes by the measurement of contact angles on thin films. Three kinds of ladderlike polymers have been synthesized: A C (which has the alkyl group and the epoxy group graft to the ladderlike polysilsesquioxane chain), A C P (which has the alkyl group, phenyl group, and epoxy group graft to the ladderlike chain), and A P (which has the phenyl group and epoxy group in the ladderlike side chain). The results showed that when different liquids and different theories are chosen to determine the surface energies, there are some minor differences in the values but a similar trend is still exhibited. The surface energies of these three polymers are in the following order of γ_{SA C} < γ_{SA C P} < γ_{SA P}. Interestingly, the surface energy increases for these polymers are mainly from the nonpolar part of the polyepoxysiloxanes. XPS surface analysis indicated that the Si and O ratios of these polymers at the air‐polymer interface were in the order of A C > A C P > A P, suggesting Si atoms were more likely to migrate to the polymer surface and the bulky effect of the phenyl groups could also interfere with the migration of the Si atoms. As a result, Si and O ratio at the interface determines the order of apparent surface energy for these three polymers. Experimental data also reflect that there are differences between the ladderlike polyepoxysiloxanes and the commercially available linear polysiloxanes. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 138–147, 2000     

含偶氮咔唑生色团氧化乙烯功能单体的合成及其聚合反应研究

设计并合成了含偶氮苯生色团的环氧类功能单体和仅含咔唑环的单体,并以一定比例通过阳离子开环聚合合成了三个新的非共轭主链具有光折变生色团的聚合物,并用GPC、DSC、FT-IR、TG和UV-Vis等手段对所得聚合物进行了表征,考察了共聚单体配比对聚合物玻璃化转变温度的影响。UV-Vis谱图说明聚合物的最大吸收波长取决于生色团的种类。DSC结果显示,通过改变两个单体的配比可以有效调节共聚产物的玻璃化转变温度。TG结果显示,聚合物具有好的热稳定性,325℃左右开始分解。     

SYNTHESIS OF HIGH THERMOSTABLE SILICONE GELS CONSTRUCTED WITH LADDERLIKE POLYSILSESQUIOXANES*

Heat-resistant silicone gels were synthesized by replacing the single main chain polymethylhydrosiloxane withreactive ladderlike polyhydrosilsesquioxane copolymers. Because of the interaction between polydimethylsiloxane chainsand the ladderlike polysilsesquioxanes chains, the cyclization of the polydimethylsiloxane chains is hindered. The highthermal stability of the ladderlike polymers can improve the thermal stability of the silicone gels without sacrificing their good comprehensive properties.     

Property changes of powdery polyacrylonitrile synthesized by aqueous suspension polymerization during heat-treatment process under air atmosphere

High molecular weight powdery polyacrylonitrile (PAN) polymers were prepared by aqueous suspension polymerization employing itaconic acid (IA) as comonomer and alpha,alpha(')-azobisisobutyronitrile (AIBN) as initiator at 60 degrees C. PAN polymers obtained with different monomer ratios were characterized by EA, DSC, FTIR and XRD. It is investigated that the oxygen element content in PAN polymers increased with the increase of required IA amounts in the feed and heat-treatment temperatures. DSC curves of PAN copolymers exhibited the triplet character, owing to the exothermic cyclization and oxidative reactions during heat-treatment process. Introduction of IA in the feed relaxed exothermic reactions of PAN polymers under air atmosphere. Structure and crystallinity changes were affected by required IA amounts in the feed and enhancement of heat-treatment temperatures. The characteristic functional groups (including C[triple bond]N, C=O, CH(2)) presented in FTIR spectra of PAN polymers indicated copolymerization reaction of AN and IA. Existence of some organic groups (C-O, C=C and/or C=N) indicated formation of ladderlike structure during heat-treatment process. PAN homopolymer had the better crystallinity (mainly peak intensity and peak area around 2theta = 17 degrees) than most RT-PAN copolymers. When heat-treatment temperature is around 210 degrees C, peak intensity, peak area, L(c) and CI of HT-PAN polymers corresponding to samples 1# and 2# got maxima, while crystallinity became weak at higher heat-treatment temperatures.     

THE HYDROSILATION REACTION OF LADDERLIKE POLYALLYLSILSESQUIOXANE(ALLYL-T)AND POLYHYDROSILSESQUIOXANE(H-T)

The one plus one (1 + 1) mode of hydrosilation reaction of ladderlike cis-isotatic polyallylsilsesquioxane (Allyl-T)and polyhydrosilsesquioxane (H-T) using dicyclopentadienylplatinumdichloride (Cp_2PtCl_2) as the catalyst leads to theformation of a new polyorganosiloxane (POS). The presence of nanoscale tubular structure in the product POS waspreliminarily proved by IR, ~1H-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeationchromatography (GPC), atomic force microscopy (AFM) and molecular simulation.     

STUDY ON THE SYNTHESIS AND CHARACTERIZATION OF THE SOLUBLE, HIGH MOLECULAR WEIGHT AND LAD D ERLIKE PO LYMETH YLSILSESQ UIO XANE

A new method for the preparation of a soluble ladderlike polymethylsilsesquioxane with high molecular weight ((?)=10~5—10~6) and low molecular weight distribution (D=Mw/Mn) in common solvents instead of the formerly used toxic methylisobutylketone has been developed. The structure and macromolecular regularity were characterized by IR, X-ray diffraction, and ~(29)Si-NMR spectroscopy. The thermal property was studied by TGA and DSC.     

Solution structure and conformational dynamics of deoxyxylonucleic acids (dXNA): an orthogonal nucleic acid candidate

Orthogonal nucleic acids are chemically modified nucleic acid polymers that are unable to transfer information with natural nucleic acids and thus can be used in synthetic biology to store and transfer genetic information independently. Recently, it was proposed that xylose-DNA (dXNA) can be considered to be a potential candidate for an orthogonal system. Herein, we present the structure in solution and conformational analysis of two self-complementary, fully modified dXNA oligonucleotides, as determined by CD and NMR spectroscopy. These studies are the initial experimental proof of the structural orthogonality of dXNAs. In aqueous solution, dXNA duplexes predominantly form a linear ladderlike (type-1) structure. This is the first example of a furanose nucleic acid that adopts a ladderlike structure. In the presence of salt, an equilibrium exists between two types of duplex form. The corresponding nucleoside triphosphates (dXNTPs) were synthesized and evaluated for their ability to be incorporated into a growing DNA chain by using several natural and mutant DNA polymerases. Despite the structural orthogonality of dXNA, DNA polymerase β mutant is able to incorporate the dXNTPs, showing DNA-dependent dXNA polymerase activity.     

A novel aryl amide-bridged ladderlike polymethylsiloxane synthesized by an amido H-bonding self-assembled template

A novel soluble aryl amide-bridged ladderlike polymethylsiloxane (A-LPMS) was synthesized by stepwise coupling polymerization on the basis of amido H-bonding self-assembling template from monomer N,N'-bis(3-methyldiethoxylsilylpropyl)-[4,4'-oxybis(benzyl amide)]. The monomer was prepared in a high yield by the hydrosilylation reaction of template agent N,N'-diallyl-[4,4'-oxybis(benzyl amide)] with methyldiethoxysilane in the presence of dicyclopentadienylplatinum dichloride (Cp(2)PtCl(2)) as catalyst. A variety of techniques including (1)H NMR, (13)C NMR, (29)Si NMR, FTIR, XRD, DSC, and, especially, static and dynamic light scattering and viscosimetry were combined to confirm the presence of the ordered ladderlike structure of polymer A-LPMS.     

生物可降解聚(5-羟基乙酰丙酸-co-L-乳酸)的合成与表征(英文)

通过5-羟基乙酰丙酸(5-HLA)与L-乳酸(LLA)的熔融缩聚合成了聚(5-羟基乙酰丙酸-co-L-乳酸)(PHLL),并用凝胶渗透色谱法、X射线衍射法、核磁共振、红外光谱和差示量热扫描法对其进行表征.结果表明,由于5-HLA的羰基与LLA的羟基发生醚化反应,使得共聚产物中存在烯醚键支化结构.在较宽的共聚组成范围内共聚物呈无定形态.同时由于共聚物中5-HLA链节中的氢键作用,使得5-HLA含量的增加可将PHLL的玻璃化温度由54.6℃提高到91.4℃.PHLL在去离子水中的降解行为表明,PHLL在水性溶液中容易发生降解,其降解速度与微观结构有关;无定形的LLA链节比5-HLA链节降解速度快.     

H-BONDING SELF-ASSEMBLED TEMPLATE-CONTROLLED SYNTHESIS OF A NOVEL SOLUBLE AND REACTIVE AMIDE-BRIDGED LADDERLIKE POLYHYDROSILOXANE

A novel soluble and reactive amide-bridged ladderlike polyhydrosiloxane （ALPHS） was first synthesized by an amido H-bonding self-assembled template. ALPHS with molecular weight M^-a = 18300 has very highly ordered ladderlike structure, which was confirmed by a sharp resonance absorption peak of [-Si（H）O2/2 ] moiety with the half peak width △1/2 〈 0.5 in^29Si-NMR spectrum. Presence of the reactive Si-H groups gives ALPHS an opportunity to further derive a variety of functional polymers by versatile Si-H reactions such as hydrosilylation, condensation, and so on.     

聚芳酯聚碳酸酯液晶共聚物的合成及表征

采用聚合物改性合成方法，以聚碳酸酯和对羟基苯甲酸苯酯（ＰＰＨＢ）为原料，克服了聚碳酸酯高温下易酸解脱羧的现象，合成了链结构为（ＯｐｈＣＯ）ｘ［ＯＰｈＣ（ＣＨ３）２ＰｈＯＣＯ］ｙ的液晶聚酯碳酸酯，并借助于ＤＳＣ，１Ｈ—ＮＭＲ，ＦＴＩＲ，ＴＧＡ，热台偏光显微镜和Ｘ光衍射等手段表征了其性能．结果表明，所合成的液晶聚酯碳酸酯具有较高的对数比浓粘度；当（ＯＰｈＣＯ）结构单元含量大于或等于５５ｍｏｌ％时，聚合物能呈现出向列型液晶行为；聚合物的Ｔｇ随着（ＯＰｈＣＯ）单元的增加而变大，并且聚合物拥有较好的溶解性能和热稳定性能     

含全氟环丁烷环可溶性聚酰亚胺的合成与表征

以乙酰氨基苯酚为原料,经过BrCF2CF2Br氟烷基化、Zn催化脱卤、热环化二聚,以及水解去保护,合成了一种含全氟环丁烷环的二胺单体1,2,3,3,4,4-六氟-1,2-双[4-(氨基)苯氧基]环丁烷.用该单体分别与酯环二酐双环[2·2·1]辛烷-2,3,5,6-四羧基2,3,5,6-二酐(BHDA)、芳香性二酐3,3′,4,4′-联苯四酸二酐(BPDA)和3,3′,4,4′-二苯酮四酸二酐(BTDA)通过“一步法”制备了3种新型含全氟环丁烷环聚酰亚胺.通过粘度测试、溶解性实验、FT-IR、热失重分析(TGA)和差热扫描量热(DSC)分析等手段,对所合成的聚酰亚胺的结构与性能进行了表征.结果显示该类聚酰亚胺可溶于大多数常用极性有机溶剂,热分解温度高于480℃,其中两种聚合物玻璃化温度低于150℃,表明含全氟环丁烷环聚酰亚胺具有良好的溶解性和可加工性.     

聚丙烯酸酯型高分子侧链液晶的合成及其对聚乙烯成核结晶行为的影响

基于聚烯烃用成核剂的结构特征设计合成了两种极性基团和非极性基团交替排列的乙烯基单体,并利用自由基引发聚合,制备出相应的侧链型液晶聚合物.采用元素分析、红外光谱和核磁共振氢谱对所合成单体和聚合物的结构进行了确认.并采用热失重(TGA)和差示扫描量热仪(DSC)研究了聚合物的热稳定性和相转变温度.结果表明,所合成聚合物的起始热分解温度均在337℃以上,具有优异的热稳定性;液晶相变温度区间可达186 K,具有较宽的液晶态温度范围.热台偏光显微镜(HS-POM)研究结果表明,聚合物均呈现出纹影织构,证明所合成的聚合物均为热致向列型侧链液晶高分子.采用DSC和HS-POM研究了所合成的侧链液晶聚合物对高密度聚乙烯(HDPE)异相成核结晶行为的影响.结果表明,侧链型液晶聚合物在提高HDPE结晶温度、结晶度以及降低HDPE晶粒的尺寸及分布方面均有优异的效果,是一类HDPE有效的成核剂.     

Synthesis,characterization, and thermal properties of ladderlike polyepoxysiloxanes

Starting from trichlorosilanes and using 1,4‐phenylenediamine as a template, we have synthesized some ladderlike poly(glycidyl‐co‐alkyl/aryl)siloxanes (polyepoxysiloxanes or polyepoxies for short). The structures of copolymers were confirmed through IR, ¹H NMR, elemental analyses, and gel permeation chromatography. Curing behaviors of these polyepoxies in the absence and presence of a curing agent have been studied with DSC. It was shown that these epoxies could be cured without any curing agent. Copolymers having aromatic groups showed higher curing reactivity than those having alkyl groups. The experimental results also demonstrate that the curing reaction occurred solely via epoxy functionality, not via the condensation reaction of the hydroxy groups located at the end of polymer main chains. The thermal stability of the cured polymers was examined by thermogravimetric analysis. The results confirm that polyepoxies with aromatic groups had better thermal stability than those with alkyl groups. It was also found that polyepoxies cured with a diamine have a higher thermal stability than those cured in the absence of a curing agent. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2215–2222, 2001