SYNOPSISThe biodegradation of several polymers that had been buried under soil for over 32 years was examined. No evidence of biodegradation was found for polystyrene, polyvinylchloride, and urea formaldehyde resin. A remarkable degradation was indicated for low density polyethylene thin films which were directly in contact with soil. Severely degraded parts of the film is characterized by whitening. Many small holes were recognized on the surface of the whitened part. The whitened part is specific for the growth of hyphae. FT-IR spectra of the whitened part showed a characteristic band in the vicinity of 1640 cm-' which was assigned to the stretching vibration of C=C bond. Although the part which was not in contact with soil was clear, it also showed evidence of degradation from the presence of carbonyl band in FT-IR. It was suggested that the degradation of the clear part is due to the usual thermo-oxidative process, while the degradation of the whitened part is due to the biotic process. 0

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The cesium fluoride (CsF)-assisted cross-coupling reaction of (1-fluorovinyl)methyldiphenylsilane (1) with aryl halides and aryl triflates was examined. The reaction with aryl iodides smoothly proceeded to afford the corresponding (1-fluorovinyl)arenes in the presence of a catalytic amount of CuI and Pd(PPh(3))(4) in aprotic polar solvents such as DMF, DMI, DMA, and NMP in good yields. A variety of functional groups (nitro, ester, ketone, and ether) on the aromatic rings can be tolerated under these mild conditions. Aryl iodides are superior to aryl bromides as the coupling reaction partner. The cross-coupling reaction of 1 with aryl triflates instead of aryl halides was also accomplished in the presence of tetrabutylammonium iodide (n-Bu(4)NI) as the additive under similar conditions.

ABSTRACT:The molecular weight reduction of low-density polyethylene (LDPE) buried under bioactive soil for 32-37 years was examined by GPC. Microscope IR spectra of the surface of the degraded sample showed the characteristic feature of biodegradation, while the inner part of the sample was almost unchanged. The number average molecular weight (M n ) of the surface was reduced to almost one-half of the inner part. Moreover, a low-molecular-weight component around a molecular weight of 10 3 was recognized for degraded samples. SEM observation suggested that the formation of the lowmolecular-weight components is the result of erosion due to enzymatic reaction. The results give evidence for the biodegradation of high-molecular-weight LDPE.