Sadao. Mori

Gel permeation chromatography of the cyclic monomers and oliglmers in nylon 6 and nylon 66

Abstract The cyclic monomers and oligomers in nylon 6 and nylon 66 were separated and determined by gel pearmeation chromatography. The gels used in the experiment were Sephadex G-15 and Bio-Gel P-4. The ethanol extracts of nylon 6 and nylon 66 were dissolved in 0.1 N hydrochloric acid which was used as an eluant. The effluent was introduced into a flow cell and the absorbance at 210 mμ was measured continously by means of a spectrophotometer. The method is applicable to 1–5 mg samples or less and the time needed for chromatography is less than 6 h. The presence of linear oligomers does not affect the determination of the cyclic oligomers. Linear relationships between log M and several elution values, vis . V e , V e / V t , V e / V o , K d , and V e /( V o + V i ), have been confirmed for the cyclic monomer and oligomers of nylon 6. Deviation from linearity of the elution values of the cyclic dimer of nylon 66 implies that the dimension of the dimer is contracted in a solution compared with others.

Gel permeation chromtography of the linear monomer and oligomers in polyamides

Abstract The linear monomers and oligomers in nylon 6, nylon 66, and nylon 12 were separated and determined by gel permeation chromatography using Sephadex LH-20 as the gel and 0.05 N HCl—methanol as eluant. The water—ethanol extractables of the polyamides were reacted with 2,4-dinitrofluorobenzene and the reaction solution was chromatographed. The effluent was channeled into a flow cell and the absorbance of the DNP-derivatives of the linear monomer and oligomers separated was measured continuously by a spectrophotometer in the 370 to 450 mμrange. The cyclic monomers and oligomers did not interfere with the separation and determination of the linear monomer and oligomers. Higher oligomers, up to the octamer of nylon 6, the tetramer of nylon 66, and the hexamer of nylon 12, were separated and determined. As little as 0.01 μmole of the DNP-derivatives has been determined. A linear relationship was obtained betwwen the elution volume and the logarithm of the molecular weight of monomer and oligomers from which that of the dinitrophenyl group had been subtracted.

Thin-layer chromatography of the linear oligomers of ethylene terephthalate

Abstract A method for the qualitative and quantitative analysis of the linear oligomers of the ester-diol type and ester-hydroxy acid type from ethylene terephthalate is described. As thin-layer chromatographic solvent systems, a chloroform-ethanol (9: i ) system is suitable for the separation of the oligoesters of the eser-diol type and a n -propanol-28% aqueous ammonia-water (70:25:5) system for the ester-hydroxy acid type. Oligoesters separated on the thin-layer chromatographic plate were sprayed with a hydroxylamine solution and then with a ferric perchlorate solution, so that purpose chelate complexes wee formed. Quantitative analysis was carried out by lifting the spots from the plate, reacting them again with the same two solutions, and, after filtration, measuring the absorption of the solution at 540 nm. The average recovery was 97%. The method could decrease the experimental errors caused by scraping off the spots, because visible spots were scraped and unreacted samples were again reacted with the same reagents.

Thin-layer chromatography of diamines, dicarboxylic acids and ω-amino acids application to the analysis of copolyamides

A method, which involves thin-layer chromatography and densitometry, was developed for the qualitative and quantitative analysis of the diamine dihydrochlorides, dicarboxylic acids, and ω-amino acid hydrochlorides recovered from acid hydrolysed copolyamides prepared from diamine—diacid and/or ω-amino acids (or their lactams). Two different solvent systems consisting of phenol—n-butanol—formic acid—water and phenol—formic acid—water were used. The qualitative analysis of the three homologous series was attained on the same chromatogram. For quantitative determination the method has an average relative error in accuracy of ±5%. A linear relationship between the R′M values [R′M = log(1/1.1 RF - 1)] and the solute carbon numbers was observed. The deviation from linearity for the longer chain compounds might be caused by a gradient effect. The linearity between RF values and the number of carbon atoms depended upon the experimental conditions.

Gas chromatographic separation of dibasic alkanoic acid dimethyl esters and the three isomeric phthalic acid dimethyl esters with a polyamide liquid phase

Abstract The complete gas chromatographic separation of the dimethyl esters of dibasic alkanoic acids (C3–C12) and the three isomeric phthalic acids was carried out using a fluoren-9-one and N-66/6 2-stage column. The greater degree of polarity of the stationary phases (N-66/6 ⪢ N-61 ⪢ N-12 and NGS ⪢ PEGS ⪢ PEG-6000) that was expected was in accordance with the shorter retention times of dimethyl azelate on these stationary phases. The differences in the elution order of the three isomeric phthalic acids on each stationary phase were interpreted from electronic theory and hydrogen bonding. Plotting the logarithm of the retention times of the diesters relative to adipic acid diester vs. carbon numbers on all stationary phases investigated gave the same straight lines, with negligible deviations.

Microcolumn Size-Exclusion HPLC

ABSTRACT High-resolution micro-SEC columns were prepared, using polyimide-coated fused silica tubing (0.35 mm I.D. and 50 cm in length). Packing materials were polystyrene gels used for oligomer separation and have average particle size of 5 or 6 urn. The number of theoretical plates on a 50-cm column was determined by injecting benzene as a solute. The maximum was 40,000 plates, while the average was 27,000. A total of 130,000 plates was attained by connecting five columns in series. These columns were applied to the separation of epoxy and phenol-formaldehyde resins.

Adsorption behaviour of aromatic nitro compounds on sephadex LH-20

Abstract By classifying the mechanism of adsorption of solutes to gels into two groups, viz., ionic effects (ion exchange, ion exclusion and ion adsorption) and pure adsorption (hydrogen bonding and π-bonding), and by considering the gel structure as hydrochloric acid, potassium hydroxide, or potassium chloride in methanol are adsorbed on to the gels and the surface of the gel becomes positively charged, the adsorption behaviour of dinitrophenyl derivatives on Sephadex LH-20 in methanol, 0.05 N hydrochloric acid-methanol, 0.05 N potassium hydroxide-methanol and 0.05 N potassium chloride-methanol have been explained. The solutes that have no dissociative groups interact with the gel only by pure adsorption. The solutes that have an acidic group interact with the gel by ion adsorption under the dissociation conditions for the solutes, and those that have a basic group by ion exclusion under both the dissociation and non-dissociation conditions. These behaviours are compared with those in methanol. Benzene or pyridine added to methanol are assumed to block the interaction sites of gels and hence lower Kd values for the solutes are obtained. The presence of two nitro groups and hydroxyl, carboxyl or amino groups on a benzene ring shows the potentiation effect of adsorption to the gel. The dissociative groups favour the ionic effects, which are than the sieving effect. A nitro group is assumed to be adsorbed to the gel by hydrogen bonding and this secondary effect is greater than the molecular sieving effect for low-molecular-weight compounds.

Identification of polymers based on elution from or retention in a silica gel column by HPLC.

固定相にシリカゲルを,検出器に示差屈折計を,移動相に試料ポリマーに対し良溶媒あるいは非溶媒を用いて,カラムからの試料ポリマーの溶出の有無を調べた.試料ポリマーはいずれにも良溶媒であるテトラヒドロフランに溶解し,カラムに注人した.試料ポリマーがカラムから溶出する場合には排除限界の位置に現れる.同定はポリマーがカラムから溶出するか,保持されて全く溶出しないかのいずれかによる方法であり(これをオン-オフ溶離法と定義する),保持容量の相違を利用する方法ではない.又ポリ塩化ビニルは二塩化エチレン移動相でカラムから溶出し,ポリ酢酸ビニルは保持される.メタノール移動相では逆になる.このことを利用し,これら二つのホモポリマーのブレンドと共重合体を識別することができた.

Comparison of analytical techniques for acrylonitrile-styrene copolymers and composition dependence of UV absorption coefficients.

アクリロニトリル-スチレン共重合体の組成分析を行ったところ,NMR法及び窒素分析法では互いに良く一致したが,UV法ではスチレン含有量が小さく見積もられることが分かった.組成の異なる共重合体を合成し,窒素分析法,NMR法,UV法,IR法により組成を求めた.窒素分析法及び NMR法によって求めた組成を基にして,UVスペクトルの各吸収極大波長における吸光係数を求めたところ,アクリロニトリル成分の結合と共に淡色効果を示すことが認められた.又吸収極大波長は浅色移動した.IRスペクトルでは,2240cm-1のアクリロニトリル成分の特性吸収はスチレン成分の結合と共に濃色効果が認められた.スチレン成分の特性吸収のうち1500cm-1では重合条件によって吸光係数に違いが認められた.一方1600cm-1ではその違いは認められなかったが,吸光係数が小さく,測定精度に問題があった.以上のことからこの共重合体の組成分析において,UV法とIR法を適用するのは適当でないと結論した.

Characterization on Poly(vinyl chloride)-Poly(vinyl acetate) Copolymer by Infrared Spectroscopy and Fractional Precipitation

PVCとP(VC-VAc)をテトラヒドロフラン- 水系およびテトラヒドロフラン-メタノール系により分別沈殿を行ない,各分別物のIRと粘度測定から次の事実が認められた。沈殿剤に水を用いた場合は重合度にしたがって分別されるが, メタノールを用いた場合は重合度の逆転がおこり,この場合は重合度のほかに結晶性にしたがって分別される。共重合物ではさらにその組成が分別結果に影響する。PVC のアイソタクチック構造とシンジオタクチック構造の相対量の大小と重合度との間に相関性がなく, また分別による相対量の変化は認められなかった。重合度の高い方が一般に結晶化度も高く, またメタノールを沈殿剤として用いた場合には高分子の結晶性が分別結果に影響をおよぼすことを赤外吸収スペクトルの測定結果から確かめた。共重合物の組成と重合度の間には1 % の有意水準で相関関係があり, 重合度の低いほど酢酸ビニル含量が多くなることが認められた。