Motoyasu Sugiura

An infrared spectroscopic study of the migration of a plasticiser in poly(vinyl chloride) resins

Abstract Migration of a plasticiser, di-2-ethylhexylphthalate (DOP), in vinyl chloride resins containing stabilisers, di- n -butyl-tin-dilaurate and di- n -butyl-tin-maleate (DBTM) under heat, accelerated weathering (SWM), outdoor exposure or warm water immersion was investigated mainly by depth analysis using Fourier-transform infrared spectroscopy. In the case of heating, the DBTM inhibited the evaporation of DOP from the surface. Electron probe micro-analysis and scanning electron microscopy indicated that the concentration of the deteriorated DBTM near the surface formed a barrier layer against the evaporation of DOP. Under the other conditions, migration of the DOP was different from that of heating, and the DBTM did not affect the evaporation of DOP. Under SWM, the evaporation of DOP was observed only from the exposed side, while it was observed from both sides under outdoor exposure. Moreover, the depth profiles of DOP in the samples exposed outdoors were similar to that of the immersed samples, which suggested that the plasticiser was extracted by water such as rainfall and dew, during the outdoor exposure.

Attenuated Total Reflection Surface-Enhanced Infrared Absorption Microspectroscopy for Identification of Small Thin Layers on Material Surfaces

Attenuated total reflection surface-enhanced infrared absorption microspectroscopy (micro-ATR-SEIRA) was developed for the identification of sub-mm size and nm-thick layers on material surfaces by using gold island films deposited on the surface of micro-ATR crystals. A thin layer of triphenyl phosphate (TPP) on a poly(tetrafluoroethylene) (PTFE) membrane filter was used to evaluate the enhancement of the absorption bands. Three types of crystals: diamond, silicon, and germanium, were evaluated. Diamond gave the greatest enhancement with a 12 nm thick gold island film. The enhancement factor was 200 times compared to bare diamond crystal, whereas it was 10 times for germanium crystal. This variation of enhancement factor according to crystal types was presumed to be due to the morphology of the gold films on the crystals. We also obtained an enhanced ATR map over an area of approximately 2 × 6 mm for a thin layer (approximately 1 nm thick) of di-2-ethylhexylphthalate on PTFE using gold-coated hexagonal silicon micro-ATR crystals. This micro-ATR-SEIRA technique has major potential for analyzing small and thin substances on material surfaces.

Distribution analysis of functional groups in polymers by derivatization-electron probe X-ray microanalysis

Abstract A new analytical method referred to as derivatization-electron probe X-ray microanalysis (XMA) has been developed to determine the distribution of 0.1% order functional groups in polymers with μm level lateral resolution. The fundamental performance of XMA in analyzing derivatized polymers has been investigated. The results showed that the detection limit for the concentration of Br in a brominated epoxy resin was 0.05% and the lateral resolution was 3 μm. Also, the optimal reaction conditions that make it possible to derivatize selectively the vinyl groups, the carboxyl groups and the carbonyl groups have been found. These conditions are the key to this method. In addition, the depth profile of the vinyl groups in amine-degraded poly (vinyl chloride) has been analyzed using this method. Since the depth profiles agreed well with those obtained by micro-IR spectroscopy, the reliability of the distribution measurement of functional groups by this method was confirmed. By this method, the sensitivity was 30 times higher, and the lateral resolution was 4 times higher than those obtained by the micro-IR spectroscopy. The actual applications to the depth analysis of degraded Nylon-6 and ethylene–carbon monoxide copolymer have proved that this method is useful for the characterization of polymers and the study of polymer degradation.

Analysis of crosslinked structure of unsaturated polyester resin.

不飽和ポリエステル樹脂 (UP) の架橋構造を解析する方法を確立した. 硬化したUPを加水分解した時に得られるビニルー酸共重合体は, 樹脂の架橋点をそのまま残している. この点に着目して, 共重合体の共重合比から“平均架橋鎖長 (Nv) ”を, また, 共重合比と収量とから“平均架橋点間主鎖長 (NE) ”を, それぞれ求めた. 一方, 共重合比と収量とを精度良く求めるための加水分解条件を, 組成既知の樹脂を用いて検討した. その結果, テフロン密封分解容器を用いて, 樹脂を2NKOHとともに150℃×20h加熱するのが最も良いことが分かった. この条件を用いることにより, 樹脂の架橋構造が変動係数3%以内の精度で求められた. さらに, 本法を硬化条件と構造との関係の解析, 及び熱処理による構造変化の解析に応用し, いずれの場合にも架橋構造の変化が明瞭に評価できることを確認した.