Daorong Dai

Synthesis and Characterization of Novel Alcohol-Soluble Ladderlike Poly(silsesquioxane)s Containing Side-Chain Hydroxy Groups

Two novel kinds of alcohol-soluble ladder-like poly(silsesquioxane)s containing side-chain hydroxy groups (OH-T 1 and OH-T 2 ) were prepared successfully for the first time by hydrolysis of ladderlike poly(silses-quioxane)s with side-chain ester groups (Ester-T 1 and Ester-T 2 ), which were synthesized by stepwise coupling polymerization. A variety of characterization methods including FT-IR, 1 H NMR, 13 C NMR, 29 Si NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vapor pressure osmometry (VPO), gel permeation chromatography (GPC), and X-ray diffraction (XRD) were combined to demonstrate that the obtained alcohol-soluble polymers have ladderlike structures, although some structural defects still existed.

A glance at the relation of stepwise coupling polymerization to supramolecular chemistry

Abstract A relationship between supramolecular chemistry and stepwise coupling polymerization (SCP) found by our group is briefly described. By SCP reaction a series of new kinds of microstructure-controlled polymers and their corresponding supramolecular inclusions such as: (1) reactive ladder-like polysiloxanes (LPS); (2) liquid crystalline ladder-like polysiloxanes and their metal complexes including fishbone-like LCPs (FBLCPs) and their metal complexes (M-FBLCPs) and rowboat-like LCPs (RBLCPs); (3) tubular polymers (TPs) and their supramolecular inclusions (TPIs) and (4) sieve-plate-like network polymers (SNPs) and their supramolecular clathrates (SNPC) have been successfully prepared. It is reasonably stated that SCP is a supramolecular interaction-aided reaction and moreover, SCP is an effective method to generate new supramolecules.

Synthesis and characterization of ladder-like copolymethyl-epoxysilsesquioxane

Abstract A new kind of copolymethyl-epoxysilsesquioxane (CPMES) was synthesized for the first time by hydrosilation reaction of allyl glycidyl ether (AGE) with the ladder-like polymethylhydrosilsesquioxane (Me-H-T) in the presence of dicyclopentadienylplatinum dichloride (Cp2PtCl2) as catalyst. The graft polymer was characterized by infrared spectroscopy (IR), 1H-NMR, 29Si-NMR, X-ray diffraction (XRD), gel-permeation chromatography (GPC), vapour pressure osmometry (VPO), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicate that CPMES possesses good solubility in organic solvents, and a greatly improved thermostability compared with polymethyl-epoxysiloxane with a single backbone.

Synthesis and characterization of two novel functional ladder-like polysilsesquioxanes for nonlinear optical response

Abstract Two novel functional ladder-like polysilsesquioxanes with double-chain macromolecular backbones and nonlinear optical (NLO) chromophore-containing side chains for NLO applications (NLO-T 1 and NLO-T 2 ) were synthesized successfully for the first time via the introduction of the NLO chromophores to the side chains of the ladderlike polychloropropylsilsesquioxane (Cl-T 1 ) and ladderlike poly(4-chloromethylphenyl)ethylsilsesquioxane (Cl-T 2 ), respectively, by an etherification reaction. The obtained polymers were characterized by FTIR, 1 H NMR, 13 C NMR, 29 Si NMR, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), vapour pressure osmometry (VPO), fluorescence spectroscopy and second-harmonic generation (SHG) measurements. The poled thin films of the above two ladder-like NLO polymers showed d 33 coefficients of 9.2 and 9.6 pm V −1 , respectively. Compared with the corresponding single main chain polymers, the poled thin films of the synthesized ladder-like NLO polymers demonstrated a much higher thermal stability of SHG.

Synthesis and characterization of novel reactive ladder‐like polysilsesquioxanes with side‐chain ester groups (Ester‐Ts)

Two kinds of structure-ordered reactive ladder-like polysilsesquioxanes with different side-chain ester groups (Ester-Ts) have been synthesized successfully by a new route – stepwise coupling polymerization – with three steps including preaminolysis, hydrolysis and polycondensation. Two monomers, 2-trichlorosilylethyl acetate (M1) and 3-trichlorosilylpropyl propionate (M2), were first synthesized by hydrosilylation with dicyclopentadienylplatinum (II) chloride (Cp2PtCl2) as a catalyst. Monomer and polymer structures were characterized by FTIR, 1H NMR, 13C NMR, 29Si NMR, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vapour pressure osmometry (VPO). Characterization data indicate that these two polymers have ordered ladder-like structures. © 2000 Society of Chemical Industry

Nonlinear optical polymer films based on sol-gel derived polysilsesquioxane with pendant chromophoric subunits embedded in size-matched pores

Two new hybrid nonlinear optical (NLO) polymeric films have been fabricated from the corresponding monomers, α, ω-bis(trimethoxysilyl)-1,4-dipropoxybenzenes bearing one or two moieties of pendant groups of N-(4)-nitrophenol-(L)-prolinol (NPP) on the spacer respectively by molecular design and “in-situ poling and sol-gel” process. These films are of enhanced thermal stability, extended temporal stability and higher second harmonic generation (SHG) susceptibilities. Their d33 values are 2.0 × 10−8 esu and 3.2 × 10−8 esu., respectively. These properties can be ascribed to the molecule-level embedment of NPP moieties in size-matched pore of the polysilsesquioxanes and fixation of the orientation of the poled chromophore given by the pore formed after the alignment of NPP moieties. The structures and morphologies of the two polymeric films investigated by XRD, FT-IR, DSC, TGA, AFM, etc. show a close correlation with the SHG properties.

Preparation of a new ladderlike oligosilsesquioxane with lateral aryl ester group

Abstract A new soluble ladder-like polysilsesquioxane with polar lateral aryl ester group, which has good adhesion properties and could be potential precursors of advanced functional materials such as catalyst carriers, polymeric solid electrolytes and microelectronic packaging materials etc., was successfully synthesized by stepwise coupling polymerization (SCP) method. The monomer used, methyl 4-trichlorosilylpropoxybenzoate, was synthesized by hydrosilylation reaction catalyzed by dicyclopentadienylplatinum(II) dichloride (Cp 2 PtCl 2 ). The titled polymer was characterized by 1 H NMR, 29 Si NMR, FTIR, X-ray diffraction (XRD) and gel permeation chromatography (GPC). The characterization data demonstrate that the polymer possesses a typical ladder-like structure.