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-controllable ordered 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 polymers such 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 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 ladderlike copolymethyl-hydrosilsesquioxane(Me-H-T),which was prepared by“supramolecular chemistry-dictated stepwise coupling polymerization”process.FT-IR,~1H-and ^(29)Si-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≡SiPrNH_2 are approximately 1:1 respectively based on the ratio of integrated resonance areas of the different groups.XRD analysis and ^(29)Si-NMR spectra are used for investigating the ladderlike structure of the polymers.A high T_g(128.38℃)of Me-AP-T shown in DSC measurement implies that the ordered reactive Me-AP-T macromolecules have much stiff chains.

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 CHARACTERIZATION OF A SOLUBLE LADDERLIKE POLYSILSESQUIOXANE CONTAINING REACTIVE ESTER GROUPS

A novel soluble ladderlike polysilsesquioxane containing reactive ester groups (Ester-T) was synthesized for the first time by stepwise coupling polymerization including preammonolysis, controlled hydrolysis and polycondensation. The monomer, 3-trichlorosilylpropoxy 4-acetoxybenzoate (M), was synthesized by hydrosilylation of allyloxy 4-acetoxybenzoate with trichlorosilane in the presence of dicyclopentadienylplatinum (II) chloride (Cp2PtCl2) catalyst. Combination of FTIR, H-1-NMR, C-13-NMR, Si-29-NMR, XRD, DSC, TGA and VPO methods was used to demonstrate that the polymer obtained has an ordered ladderlike structure. The synthesized Ester-T may have promising applications as a precursor of advanced functional polymers.

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 x 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 reactive polysilsesquioxanes, which can be used as potential precursors in the synthesis of functional ladderlike polymers.

H-bonding template-directed synthesis of a complete m-PDA-bridged ladder polyhydrosiloxane (OLPHS)

A highly ordered m-phenylenediimino-bridged ladder polyhydrosiloxane （abbr. OLPHS） with Mn = 1.24 × 10^4 was synthesized stoichiometric hydrolysis and dehydrochlorination condensation reaction between Si-Cl and Si-OH bonds. The complete ladder structure of OLPHS has been confirmed by the following three data. Two characteristic Bragg＇s peaks representing the ladder width （w = 0.94 nm） and ladder thickness （t = 0.42 nm） were observed in XRD analysis, which are consistent with those calculated by molecular simulation. The very sharp absorption with a small half-peak width （w1/2 = 0.5 ppm） for [（-HN）HSiO2/2]n moiety of OLPHS in ^29Si NMR spectrum indicated presence of the complete ladder structure. As collateral evidence, a higher glass transition temperature （Tg = 105 ℃） is also recorded in the DSC measurement, implying the high stiffness of ladder chain of OLPHS.

H-Bonding Self-assembled Template-directed Synthesis of a Reactive Amide-bridged Ladder Polyvinylsiloxane

A novel, reactive amide-bridged ladder polyvinylsiloxane （abbr. LP） with Mn= 2.4×10^4 was synthesized for the first time by means of aryl amide H-bonding self-assembled template. The regularity of LP was characterized by the XRD, ^29Si NMR and DSC methods. XRD analysis demonstrated the ladder width w = 9.09A and the ladder thickness t = 3.89A, respectively, which are approximately consistent with the molecular simulation-calculated ones： w＇= 10.60A and t＇= 3.06A. ^29Si NMR displayed a resonance peak with small half peak width, △1/2 - 4 ppm, for the moiety [=Si（Vi）O2/2-]n of LP. Besides, as a collateral evidence, DSC measurement revealed a high glass transition temperature Tg = 225℃, suggesting high stiffness of the ladder main chain of LP.