Reactive & Functional Polymers 39 (1999) 1–7

Synthesis and characterization of reactive ladderlikepolyallylsilsesquioxane and polyvinylsilsesquioxane

*Ze Li, Xinyu Cao, Hui Xu, Ping Xie, Ming Cao, Rongben ZhangPolymer Chemistry Laboratory, Chinese Academy of Sciences and China Petrochemical Corporation, Institute of Chemistry,

Chinese Academy of Sciences, Beijing 100080, China

Received 3 April 1997; received in revised form 13 August 1997; accepted 7 October 1997

Abstract

Ordered reactive ladderlike polyallylsilsesquioxane (hereafter referred to as Allyl-T) and polyvinylsilsesquioxane(hereafter Vi-T) were synthesized via stepwise coupling polymerization. During this reaction, coupling agent p-phenyl-enediamine (PDA) is supposed to act as a template which enables silane molecules to self-assemble through stronghydrogen-bonding interaction between Si–OH groups and N–H groups. The structure of the polymers was characterized by

1 13 29IR, X-ray diffraction, DSC, GPC, H-NMR, C-NMR and Si-NMR. The data show that the two polymers have orderedladderlike molecular structure. Hence, the stepwise coupling polymerization is suitable to synthesize ladderlike poly-silsesquioxanes (LPSs) containing grafted reactive vinyl-terminated groups. 1999 Elsevier Science B.V. All rightsreserved.

Keywords: Ladderlike polysilsesquioxane; Stepwise coupling polymerization

1. Introduction Suminoe et al. [4] prepared ladderlike poly-methylsilsesquioxane (Me-T) by hydrolysis of

Since Brown et al. [1] first reported the methyltrichlorosilane followed by consecutivesynthesis of the high molecular weight tractable condensation of the hydrolyzate. Yamazaki et al.ladderlike polyphenylsilsesquioxane (Ph-T) by [5] tried to synthesize reactive Vi-T by the sameequilibration polymerization in 1960, many method as that reported by Brown et al. [1] andpolymer chemists around the world have been obtained unfortunately only a gel. Saito et al.interested in this kind of special polymer. Frye [6] and Ito et al. [7] patented the preparation ofand Klosowski [2] pointed out that the polymer Allyl-T and Vi-T without describing any con-synthesized by equilibration polymerization vincing structural characterization. In recentdoes not have a highly ordered ladderlike years, Chinese chemists [8–14] have also madestructure and that there are many structural extensive studies on structural characterizationdefects such as branches in the polymer. An- and physical properties of Ph-T.drianov et al. [3] obtained Ph-T by equilibration In order to synthesize reactive ladderlikepolymerization of octa(phenylsilsesquioxane). polymers, our group has gradually developed a

new polymerization method, called ‘stepwise*Corresponding author. coupling polymerization’. It involves pre-

1381-5148/99/$ – see front matter 1999 Elsevier Science B.V. All rights reserved.PI I : S1381-5148( 97 )00148-X

2 Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7

aminolysis of trichlorosilane, followed by hy- 2.3. Synthesisdrolysis and polycondensation (see Section 3.1).

2.3.1. Preparation of allyltrichlorosilaneRecently, we have synthesized a series of alkyl-(CH =CHCH SiCl )or aryl-substituted ladderlike polysilsesquiox- 2 2 3

Referring to Ref. [18], a solution of 122.4 ganes, Me-T [15] and Ph-T [16], and especially,(1.6 mol) of CH =CHCH Cl and 38.4 g (1.76reactive polyhydridosilsesquioxane (H-T) [17] 2 2

mol) of HSiCl was slowly dropped into a 2000by this method. 3

ml three-necked flask charged with 500–800 mlBecause vinyl and allyl groups are reactiveof ether, 161.1 g (1.6 mol) of triethylamine andgroups that can be further functionalized by8.0 g (0.08 mol) of cuprous chloride, Cu Cl , athydrosilylation reaction, oxidation or condensa- 2 2

5–108C. Then the reaction system was stirredtion reactions, and thermo- or photo-crosslink-for 4 h at ca. 248C. The target product, aing as well, a variety of functional polymerscolourless liquid, was obtained, b.p. 116–1188C,such as organic / inorganic hybrid materials,in 58% yield.microscopically controllable supramolecules

and low decay second harmonic generation2.3.2. Synthesis of Allyl-Tnonlinear optical (SHG-NLO) polymers can be

A solution of 50 ml of acetone and 5.4 gprepared from Vi-T or Allyl-T used as pre-(0.05 mol) of PDA was added dropwise into acursors or starting reagents. The preparation of250-ml three-necked flask containing 50 ml ofVi-T and Allyl-T, therefore, is very importanttoluene and 8.8 g (0.05 mol) ofand promising for new advanced materials. ThisCH =CHCH SiCl at ca. 2 108C, and in turn,paper deals with the synthesis of Vi-T and 2 2 3

the reaction solution was stirred for 30 min atAllyl-T by stepwise coupling polymerizationlow temperature (25 to 2 108C), then 15 ml ofand their detailed structural characterization.acetone, 4 g (0.05 mol) of pyridine and 1.4 g(0.078 mol) of water was dropped into the flaskat 2 108C. After that, the reaction system was2. Experimentalstirred for an additional 5 h at ca. 208C. Thefinal prepolymer solution was washed with2.1. Materialswater until neutral and dried with anhydrous

All the reaction reagents and solvents are Na SO overnight. The polycondensation pro-2 4

commercially available and of analytical grade cess was carried out in presence of severalexcept for allyltrichlorosilane, which was pre- drops of triethylamine as catalyst and the re-pared as shown below. action solution was stirred for about 3 days at

308C, then the polymer solution was washedwith water until neutral and dried with anhydr-2.2. Techniquesous Na SO again. After the polymer was dried2 4

in vacuum oven at room temperature, a solidThe X-ray diffraction analysis was recordedfilm was obtained in 60% yield and the averageon a Rigaku DMAX/38 diffractometer (Japan).

51 13 29 molecular weight is higher than 9 3 10 Dalton.H-NMR, C-NMR and Si-NMR spectra werecarried out on a Varian Unity 200 (USA). TheIR measurement was performed with a Specord 2.3.3. Synthesis of Vi-T75-IR (Carl Zeiss, Jena, Germany). The DSC A solution of 5.4 g (0.05 mol) of PDA and 50experiment was made on a thermal analysis ml of acetone was added dropwise into a 250-instrument, Perking Elmer model PE-4 (USA). ml three-necked flask containing 8.1 g (0.05The GPC was measured on a LC-4A instrument mol) of vinyltrichlorosilane and 50 ml of(Shimadzu, Japan) with polystyrene as standard. toluene under 2 58C. The reaction system was

Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7 3

stirred for 30 min at below 08C. Then, 1.4 ml tion reaction with hydrochloride in such con-(0.077 mol) of water, 4.0 g (0.05 mol) of dition. The second reason is that allyl–siliconpyridine and 15 ml of acetone were dropped bond is very sensitive to hydrolysis at acidicinto the flask at 2 58C and further stirring at ca. media.258C was continued for a few hours. Water was Furthermore, the concentration of the reactionadded to the flask until the precipitated amine solution should be relatively low in preparationsalt was dissolved, the organic layer was sepa- of Vi-T, meanwhile, it should be relatively highrated, and washed with water until neutral, it in preparation of Allyl-T due to lower silanol’swas dried with anhydrous Na SO overnight. activity of Allyl-T than that of Vi-T.2 4

After the acetone was distilled out condensation The preparation condition mentioned above isreaction was carried out using triethylamine as rather mild compared to the method of Brown etcatalyst, the solution was stirred at about 308C al. [1] that strong alkali (KOH) and highfor 24 h. Finally, a pale–yellow polymer with temperature (2508C) are needed and so de-

5M 5 9 3 10 Dalton was obtained in 76% composition of alkenyl–silicon bond, especiallyw

yield. allyl–silicon bond can readily occur. The step-wise coupling polymerization reaction, there-fore, is more suitable to prepare reactive LPSs.

3. Results and discussions3.2. Characterization of Vi-T and Allyl-T

3.1. Synthesis of Vi-T and Allyl-TThe characterization data of IR, NMR, DSC,

It is supposed that in the synthetic route of GPC and X-ray diffraction are listed in Table 1.Vi-T and Allyl-T as shown in Scheme 1, the IR spectra of the Allyl-T and Vi-T demon-key point is the template effect of coupling strate that the polymers contain Si–OH,agent, PDA. For example, the first step is that .C=C,, Si–O–Si and Si–C bonds.

1PDA reacts with trichlorosilane to form inter- In the H-NMR spectrum of Vi-T, there ismediate A in which the p-phenylenediamine- one peak representing –CH=CH group, which2

bridged spacer can act as a template making can be split into two groups of sub-peaks byadjacent molecules to self-assemble side by side computer simulation. One group of peaks repre-through interactions of hydrogen-bonding of sents –CH= and the other one represents =CH2] ]amino group (N–H? ? ?N) to form ordered align- with the ratio of area of 1 : 2. In the spectrum ofment as B. Then, via following hydrolysis the Allyl-T, there are three groups of peaks repre-H-bonding-associated oligomeric silanols such senting =CH–, =CH , –CH –, respectively.2 2] ] ]as C, D, E and F are subjected to further And the ratio of area is 1 : 2 : 2.

13condensation to form an ordered LPS. Obvious- In the C-NMR spectrum of Vi-T, there arely, the high regularity of polymers mainly two peaks representing =CH– and –CH –,2] ]results from template effect of PDA and H- respectively. Meanwhile, three peaks represent-bonding-controlled self-assembly of the silanes ing –CH=, =CH and –CH respectively can be2 2] ] ]concerned. Therefore, it is possible to prepare observed from the spectrum of Allyl-T.

29ladderlike polymers with higher regularity if In the Si-NMR spectra of Vi-T and Allyl-Tmore suitable templating agent can be found. shown in Figs. 1 and 2, there are two groups of

On the other hand, it is necessary to add peaks. The large peak (b ) represents the perfectstoichiometric pyridine into the reaction solu- Si-atom of –SiO unit in the double chain3 / 2

tion to absorb hydrochloride produced in the while the small peaks (a) represent the defec-process of hydrolysis. The first reason is that tive Si-atom connected with at least one hy-vinyl and allyl groups can easily undergo addi- droxy group. It can be estimated that the

4 Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7

Scheme 1. The proposed reaction route of synthesis of Allyl-T (R=Allyl) and Vi-T (R=Vinyl) by precoupling, hydrolysis andpolycondensation.

Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7 5

Table 1Characterization data of Allyl-T and Vi-T

Items Vi-T Allyl-T

Appearance Pale–yellow solid film Similar to Vi-TSolubility Soluble in toluene, tetrahydrofuran, and chloroform etc. Similar to Vi-T

5 5M by GPC 9310 .9310w21IR (cm ) 3460 (–OH) 3460 (–OH)

3060 (n ) 3070 (n ).C=C–H .C=C–H

1600 (n ) 1630 (n ).C=C, .C=C,

1125 (Si–O–Si) 1100|1050 (Si–O–Si)765 (Si–C) 750 (Si–C)

1H-NMR (d in ppm) 5.95 (–CH=CH ) 1.62 (–CH CH=CH )2 2 2]4.95 (–CH CH=CH )2 2]5.78 (–CH CH=CH )2 2]13C-NMR (d in ppm) 130.1 (–CH=CH ) 20.1 (–CH CH=CH )2 2 2] ]

136.1 (–CH=CH ) 115.4 (–CH CH=CH )2 2 2] ]132.1 (–CH CH=CH )2 2]29Si-NMR (d in ppm) 286.2 Vi–SiO 277.3 Allyl–SiO3 / 2 3 / 2

277.0 Vi–SiO(OH) 268.2 Allyl–SiO(OH)29Regularity (R) [R 5 A /(A 1 A )] by Si-NMR 80.70% 83.62%b b a

˚Distance (A) /2u (8) by X-ray diffraction 9.3 /9.6 and 3.99/22.3 11.2 /7.88 and 4.2 /21DSC Almost horizontal T 5 1298Cg

29Fig. 1. Si-NMR spectrum of Allyl-T.

regularity, R, of Vi-T and Allyl-T are 80.70% polymerization is suitable to synthesize theand 83.62% respectively, through calculation ordered LPSs, especially the reactive LPSs.the ratio of the peak area [R 5 A /(A 1 A )]. X-ray diffraction patterns of Vi-T and Allyl-Tb b a

The results indicate that the stepwise coupling shown in Figs. 3 and 4 give two peaks respec-

6 Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7

29Fig. 2. Si-NMR spectrum of Vi-T.

both Allyl-T and Vi-T possess an orderedstructure.

The DSC curve of Vi-T featuring an almosthorizontal line without T in the range of 50–g

3008C demonstrates the great rigidity of theladderlike macromolecular backbone. Mean-while, the DSC curve of Allyl-T with a mildglass transition demonstrates comparatively lowrigidity of the polymer generated by bulkyAllyl-group.

Fig. 3. X-ray diffraction pattern of Allyl-T. 4. Conclusions

(1) Two kinds of reactive ordered LPSs (Vi-T and Allyl-T) were successfully synthesized bystepwise coupling polymerization. The goodregularity of polymers is reasonably attributedto the template effect of p-phenylenediamine.

(2) The ladderlike structure and good regu-larity of such polymers were proved by a seriesof characterization methods.

(3) Stepwise coupling polymerization, due toits mild reaction condition which may avoid

Fig. 4. X-ray diffraction pattern of Vi-T.decomposing the reactive organofunctionalgroups, is particularly suitable to prepare reac-

tively. Referring to the work of Brown et al. [1] tive LPSs.and Shi et al. [10], the first sharp peak repre-sents the plane-to-plane distance which corre-sponds to the chain-to-chain distance. The sec- Acknowledgementsond diffusing peak covers a wide range ofdiffraction angle which represents the thickness The authors express thanks to Beijingof the molecular chains. These results indicate Zhongguanchun Associated Centre of Analysis

Z. Li et al. / Reactive & Functional Polymers 39 (1999) 1 –7 7

[8] Zhang Xinsheng, Chen Suming, Shi Lianghe, Chinese J.and Measurements for providing instrumentalPolym. Sci. 5(2) (1987) 162.facilities. The project was supported by the [9] Zhang Xinsheng, Shi Lianghe, Chinese J. Polym. Sci. 5(3)

NSFC (No. 59483001). (1987) 197.[10] Shi Lianghe, Zhang Xinsheng, Shi Yuandong, Ye Meiling, Li

Dingcai, Chinese J. Polym. Sci. 5(4) (1987) 359.[11] Huang Chaoran, Xu Guanzhi, Zhang Xinsheng, Shi Lianghe,References

Chinese J. Polym. Sci. 5(4) (1987) 347.[12] Fang Zhengping, Li De, Qin Anwei, Yu Tongyin, Chinese J.

[1] J.F. Brown Jr., J.H. Vogt Jr., A. Katchman, J.W. Eustance, Polym. Sci. 5(4) (1987) 332.K.M. Kiser, K.W. Krantz, J. Am. Chem. Soc. 82 (1960) [13] Fang Zhengping, Qin Anwei, Yu Tongyin, Chinese J. Polym.6194. Sci. 5(4) (1987) 340.

[2] C.L. Frye, J.M. Klosowski, J. Am. Chem. Soc. 93 (1971) [14] Zhang Xinsheng, Shi Lianghe, Huang Chaoran, Chinese J.4599. Polym. Sci. 5(4) (1987) 353.

[3] K.A. Andrianov, G.A. Krakov, F.F. Suschentsova, V.A. [15] Xie Zusho, He Zhiqun, Dai Daorong, Zhang Rongben,Miagkov, Vysokomolek. Soidin. 7 (1965) 1477. Chinese J. Polym. Sci. 7(2) (1989) 183.

[4] T. Suminoe, Y. Matsumura, O. Tomomitsu, Japanese Patent [16] Xie Zusho, Dai Daorong, Zhang Rongben, Chinese J. Polym.Kokoku-S-60-17214, 1985 (Kokai-S-53-88099, 1978). Sci. 9(3) (1991) 265.

[5] N. Yamazaki, S. Nakahama, J. Goto, T. Nagawa, A. Hirao, [17] Xie Zusho, Jin Shunzi, Wan Youzhi, Zhang Rongben,Contemp. Top. Polym. Sci. 4 (1984) 105. Chinese J. Polym. Sci. 10(9) (1992) 361.

[6] K. Saito, S. Fukuyama, S. Shiba, Y. Kawasaki, Japanese [18] N. Furuya, T. Sukawa, J. Organometal. Chem. 96 (1975)Patent Kokai-S-63-6544, 1988. C1-C3.

[7] T. Ito, Y. Yamashita, R. Kawatsu, H. Jimbo, Japanese PatentKokoku-H-5-16457, 1993 (Kokai-S-62-283128, 1987).