Ryozo Sakata

Infra-red spectra of polyethers: I. Polyalkylene oxides☆

Abstract Infra-red spectra of polypropylene oxide, polybutadiene monoxide and polystyrene oxide have been studied. 1. (1) Polypropylene oxide Detailed assignments of the infra-red absorptions of this polymer in the region of 3300–650 cm −1 have been made with the help of polarized spectra of oriented samples. These assignments suggest that the major differences between the infra-red spectra of amorphous and crystalline samples of polypropylene oxide are due to rotational isomerism. It is proposed that trans and gauche forms exist in the amorphous portion of the polymer and that the trans form exists in the crystalline portion of the polymer. 2. (2) Polybutadiene monoxide The bands assigned to the open chain C-O-C stretching mode and the two bands assigned to the CH 2 and CH out-of-plane deformation modes of the vinyl group were observed and it is suggested that the polymer results from successive opening of the epoxy-ring. Polarized infra-red spectra suggest that the polymer possesses a compressed trans zigzag configuration. 3. (3) Polystyrene oxide The infra-red dichroism of the 697 and 755 cm −1 bands is perpendicular, and consequently the plane of the benzene ring may be nearly parallel to the direction of orientation. The shape and intensity of some bands are similar to those of crystalline isotactic polystyrene. Consequently the molecular structure of polystyrene oxide may be helical.

Polymerization of Propylene Oxide by Diethylzinc-α,β-Unsaturated Ketone Systems

Abstract Propylene oxide was polymerized by a catalyst consisting of diethylzinc and α,β -unsaturated ketones. Ten α,β -unsaturated ketones and some other related compounds were examined. All methyl ketones were effective. α,β -Unsaturated phenyl ketones were effective except for a α,β-disubstituted derivative. α,β-Unsaturated carbonyl compounds other than ketones were practically ineffective. The initial step of the catalyst formation is considered to be the reaction of diethylzinc and α,β-unsaturated ketone which is either the conjugate addition to the α,β-unsaturated group or the hydrogen abstraction from the methyl group next to the carbonyl group. The conjugate addition gives the catalyst having larger activity and better stability at high temperature.

Polymerization of Alkylene Oxides

A review of catalysts for the high polymerization of alkylene oxides was given, from which it was deduced that a metal-oxygen bond was an essential element of active species in most cases.Then, two catalytic systems which were found in our laboratory were discussed. First, the active species of the system of diethylzinc and water was mentioned, and the reaction mechanism was suggested. The second system consists of an organometallic compound and an acidic oxide such as alumina or silica-alumina. These systems induce anionic polymerization of alkylene oxide and it can be assumed that adsorption of monomer on metal of the metal-oxygen bond plays an influential role both in activation of monomer and in controlling the stereoregularity.

Polymerization of Propylene Oxide and Vinyl Compounds with Diethylzinc in the Presence of Cocatalysts

次のような2 成分系触媒を用いて, 弾性固体のポリプロピレンオキシドが得られた。ジエチル亜鉛- 酸素, ジエチル亜鉛-水,ジエチル亜鉛-メタノール,ジエチル亜鉛-エタノール。得られた重合物中には結晶性重合物が含まれている。酸素,メタノール,エタノールを1成分とする触媒では,亜鉛アルコキシドが重要な役割を演じているものと思われる。ジエチル亜鉛- 水系での触媒活性成分は黄色の固体であって, 次のような構造が重要な役割を演じているものと思われる。C2H5-Zn-O-Zn-およびC2H5O-Zn-O-Zn-。この黄色固体をn-へキサンに溶かして得られる触媒溶液は外観上完全に透明であるが,不均一系である。これらの触媒によりビニル化合物も重合するが,ビニル重合はラジカル機構で,プロピレンオキシドの重合はイオン機構で進行すると思われる。

Vinyl Polymerization with Diethyl Cadmium as Initiator

ジエチルカドミウムには数種のビニルモノマーの室温重合を開始する能力があり,その連鎖生長段階はラジカル反応であることが明らかになった。この重合反応は酸素あるいは遷移金属酸化物の共存によって加速される。また,メタクリル酸メチルの重合において,キノン類あるいはフェノール類がすぐれた助触媒作用を示すことが見出され,特にカテコール,レゾルシン,ヒドロキノン,ピロガロールなどを助触媒として使用すると,生成ポリマーの分子量はいちじるしく大であった。ジエチルカドミウム- 四塩化チタン触媒系を用いた場合には, 極性モノマーの重合速度はジエチルカドミウム単独触媒の時よりも低下するが,スチレン,ブタジエンなどのごとき非極性モノマーの重合は加速された。この触媒系を用いて得たポリスチレンには, 1ないし2%のアイソタクチックポリマーの含まれていることが認められた。