Investigation of the detection limit for the determination,by pyrolysis-capillary GC,of the thickness of ultra thin PMMA layers coated on to PET film

The determination of nanometer thick layers of poly(methyl methacrylate) coated on to the surface of poly(ethylene terephthalate) film has been investigated by high resolution pyrolysis gas chromatography without sample pretreatment or modification of the instrumentation used. A good linear relationship was observed between the quantity of the characteristic pyrolysate and the thickness of the poly(methyl methacrylate) layer; the detection limit was sufficient to enable the quantitation of poly(methyl methacrylate)-to-poly(ethylene terephthalate) film thickness ratios of 1:20000 in composite materials.     

Some factors related to social mobility in Japan

This paper summarizes some hitherto unpublished findings on factors affecting or resulting from social mobility, based on data obtained from the Social Stratification and Social Mobility Survey conducted in 1955 by the Research Committee of the Japan Sociological Society.¹⁾ Section I is concerned with factors related to inter-generation occupational mobility, Section II with inter-generation educational mobility, and Section III with occupational mobility within the individual’s lifetime. In additon, in Section IV relations between social mobility and respondent’s attitudes will be dealt with.     

Spectrophotometric determination of boron in plants after separation as trimethyl borate by microdiffusion

A sensitive and precise method based on microdiffusion is proposed for the determination of traces of boron in plants. A sealed digestion bomb is used; the powdered sample is dissolved in ZnCl₂/AlCl₃ solution containing methanol in the teflon vessel and the trimethyl borate formed is collected in sodium hydroxide pellets. The boron, as an ion-associate of the 2,6-dihydroxybenzoic acid complex and malachite green, is extracted into chlorobenzene. At 629 nm, Beer's law is obeyed for the range 0.05–0.5 μg of boron. The accuracy of the proposed method was confirmed by analyzing the Orchard Leaves and Pepperbush standards.     

Synthesis and Characterization of Photocrosslinkable Biodegradable Polymers Derived from 4‐Hydroxycinnamic Acid

A novel series of photocrosslinkable biodegradable polymers was prepared by a high‐temperature solution polycondensation from a dichloride of 4,4′‐(adipoyldioxy)dicinnamic acid (CAC) and alkane diols of various methylene lengths (HO(CH₂)_nOH; n = 6–10) or poly(ethylene glycol)s (PEG) of various molecular weights . The CAC was synthesized by the condensation of adipoyl chloride and 4‐hydroxycinnamic acid. The chemical structures and properties of these polymers were characterized by elemental analysis, ultraviolet‐visible spectroscopy (UV‐VIS), Fourier transform infrared spectroscopy (FT‐IR), ¹H NMR spectroscopy, differential scanning calorimertry (DSC), and thermogravimetry (TG). All polymers had a high molecular weight and good solubility in organic solvents. DSC showed that T_m values of CACn (134–180 °C) were much higher than those of CACEm (25–56 °C). The CACE200 degraded very rapidly in the buffer solutions (pH 7.2) of Ps. Cepacia or Rh. delemar lipase at 37 °C, while CACn resisted the hydrolysis by these lipases during the test period. The ultraviolet light irradiation (λ ≥ 280 nm) caused the photocrosslinking reaction by an intermolecular dimerization at ambient temperature without a photosensitizer, as examined by UV‐VIS, FT‐IR spectroscopy, and gel formation. The gels prepared from CACEm (m ≈ 1 000) were swollen in water and showed characteristic properties of a hydrogel. The irradiation time and the molecular weight of PEGs controlled the degree of swelling of these hydrogels. The CACE8 300 gel irradiated for 20 min showed the largest degree of swelling of 10.5.

Weight loss of a CACE200 film as a function of time in a phosphate buffer solution containing no lipase (□), Ps. cepacia lipase (?), or Rh. delemar lipase (○) at 37 °C.