Search

Poly-α-deuteroacrylonitrile and poly-α,β,β-trideuteroacrylonitrile were synthesized. α-Deuteroacrylonitrile was prepared by the deuterium exchange reaction of acrylonitrile with D2O in the presence of CaO. α,β,β-Trideuteroacrylonitrile was prepared by the addition reaction of C2D2 and DCN. The infrared spectra of polyacrylonitrile, the deuterated polyacrylonitriles, and the intermediate products of the syntheses were measured in the 4000–400 cm.-1 region and discussed. The polarized spectra of the oriented polymer samples were also measured. The bands of PAN in the CH stretching region exhibit reasonable shifts in the spectra of the deuterated polymers, while the C≡N stretching band shows no appreciable shift. The bands in the region lower than 1400 cm.-1 exhibit complicated behavior in deuteration. The calculation of the normal vibrations of polyacrylonitrile has been made, assuming a syndiotactic planar zigzag chain as a most simple model for calculation. The assignments of the bands are discussed.

重合条件の異なる16種類のポリアクリロニトリル (PAN), およびポリ-α-重水素化アクリロニトリル (PAN-αd1) について, NaCNSの重水溶液を溶媒として高分解能核磁気共鳴スペクトルを測定した。PANのメチレン基プロトンの共鳴スペクトルはSyndiotactic部分とIsotactic部分とによる二つのTripletの重なりと考えられ, それらの面積強度を別々に算出することによって各試料の立体規則性を推定することができた。ラジカル重合および常温のアニオン重合でつくったPANは約75%のSyndiotactic部分を含み, 低温アニオン重合, 固相放射線重合, Mg分子線法および尿素包接化合物の放射線重合により得たPANではSyndiotactic部分がやや少ないが, いずれも顕著な立体特異性は示していない。

Kinetic Studies on Transesterification Reactions between Poly (ethylene terephthalate) and Poly(ethylene sebacate)

A valence force field for nitriles based on the force field obtained for hydrocarbons is found to give very good agreement with the observed bands for several mono- and di-nitrile molecules. The average deviation between observed and calculated frequencies for the 238 assigned frequencies is 0.98%. This is a significant improvement over the results obtained previously with a Urey-Bradley force field.

High-resolution nuclear magnetic resonance (NMR) spectra of several kinds of polyesters were measured. Proton signals due to heterolinkages could be observed in some copolyesters, and the average sequence length and the degree of randomness in the copolyester were calculated from the intensities of their signals. A process in the transesterification reaction between two kinds of homopolyester was pursued with the NMR spectra. Random copolyester is formed by the ordinary molten-state copolycondensation and also during the transesterification reaction between two kinds of homopolyester.

ポリアクリロニトリル〓, (PAN) とその3種の重水素化物, -〓-(PAN-αd1), -〓-(PAN-βd2) および-〓-(PAN-d3) を合成し, それらの赤外スペクトルを4000～200cm-1の波数領域について測定した。PANのC-H伸縮振動に基く3個の吸収帯およびCH2はさみ振動による吸収帯は重水素化により予想される波数に移動し帰属が可能である。しかし, その他の1400cm-1以下に見られる吸収帯は重水素化物のスペクトルとの比較のみでは帰属が困難である。PANおよび3種の重水素化PANについて, Urey-Bradley力場を用い, GF行列法による基準振動の計算を行なった。分子構造は計算のために最も簡単であり, かつ可能性のあるモデルとしてシンジオタクチック平面ジグザグ鎖を仮定した。計算の結果は実測値との間に比較的よい一致が見られ, 各吸収帯の帰属を推定することができた。

種々の縮合系3ポリマーにっいて, NMR測定で結合の変わり目が検出できるかどうかを検討し次のことが明らかになった。1) 同種系コポリマー (コポリ手ステルなど) では, 注目しているユニットに結合している他のユニットが芳香族と飽和脂肪族の組み合わせのときに検出できるが, そのしやすさはコポリエステル> コポリアミド> コポリウレタン> コポリウレアである。2) 異種系コポリマー (コポリウレタンーカーボネート, コポリアミドーウレア, コポリアミドーウレタン, コポリウレアーウレタン, コポリエステルーウレタン, コポリエステルーアミド) の場合は, 注目しているユニットに結合している他のユニットの芳香族, 飽和脂肪族の差のほかに結合の種類によっても異なり一般的なことはいえない。3) 溶融法で得られたポリ (ネオペンチルテレフタレートーコセバケート) はほぼランダムに近く, 界面重縮合法で得られたコポリウレタンーカーボネートは多少ブロック性を有する。

Polarized infrared spectra of polyacrylonitrile, poly‐α‐deuteroacrylonitrile, poly‐β,β‐dideuteroacrylonitrile and poly‐α,β,β‐trideuteroacylonitrile have been measured in the region from 4000 to 200 cm—1. β,β‐dideuteroacrylonitrile was prepared by the hydrogen re‐exchange reaction of α,β,β‐trideuteroacrylonitrile with H2O in the presence of CaO. The calculations of the normal vibrations of polyacrylonitrile and these three polydeuteroacrylonitriles have been made, assuming a syndiotactic planar zigzag chain as the most simple model for calculation. The calculation was made by the use of the GF‐matrix method with the Urey—Bradley force field. The results show fairly good agreement between the observed and calculated frequencies. The assignments of the bands are given and discussed.

Gelation of poly(ethylene terephthalate) by heating at 263°–300°C was investigated. Under nitrogen flow, crosslinks were scarcely formed. However in air, degradation and crosslinking were common, and these were accelerated by purging gaseous and sublimable degradation products out of the system with a stream of air. The main component of the sublimate was terephthalic acid. Infusible and insoluble gel was treated with methanol at 260°C, and then the methanolysis products were separated into two parts. The methanol-insoluble part exhibited a polyene structure with ester groups, and the methanol-soluble part contained dimethyl terephthalate, ethylene glycol, and some 1,2,4-butanetriol. To clarify the relation between the crosslinking and the formation of vinyl ester groups, the degradation of vinyl methyl terephthalate was studied. Thermoxidative degradation of linear polyesters other than poly(ethylene terephthalate) was also studied. Poly(ethylene isophthalate) and poly(ethylene sebacate) were easily gelated. However, poly(trimethylene terephthalate) and poly(neopentyl terephthalate) were scarcely gelated. The primary reaction leading to crosslinking is assumed as follows. At first, the random scission of polyester chain may take place forming carboxylic acids, vinyl esters, aldehydes, etc. After accumulation of vinyl esters to some extent, vinyl polymerization of the esters takes place and network structures are formed.

配列の良いポリアクリロニトリルフィルムの赤外二色性を測定し, 先にKrimmらが報告したスペクトルと比較して, 吸収帯の分れ方や二色性について二, 三の異なる点を見出した。また, 吸着水にも赤外二色性が認められる。