Shin Tsuge

Degradation and Stabilization of Polymeric Materials. Thermal Degradation Behavior of Polymers.

高分子の熱分解反応は,一般に複雑で極めて多岐にわたっており,その化学構造はもとより,高分子の形態や加熱条件によっても大きく変化する.本稿では,いくつかの典型例を挙げながら高分子の熱分解機構を概説する.さらに,実用的な領域における高分子の熱分解の制御と安定化,およびその積極的な活用についても述べる.

Characterization of Photo-Yellowing Trigger Compounds Repressing Paper Recyclability of Eucalyptus globulus by Pyrolysis-GC/MS

Aucalyptus is a widely utilized species in tree plantation, especially intended for pulp production [1]. E. globulus is one of the fast growing species in tempertae zone with a rotation period of 8–10 years [2]. We have reported that chemithermomechanical pulp (CTMP) paper prepared from several individuals of E. globulus showed high brightness (about 70% ISO) with more than 85% pulp yield [3]. To construct an effective carbon loop, higher paper recycling rate is preferable. The degree of photo-yellowing is crucial for recycling in CTMP paper because it determines requirement amount of bleaching agents. The photo-yellowing mechanism is proposed in which the photochemical reaction of lignin in pulp may lead to the formation of quinone species via intermediates of phenoxy radicals, which are produced through photoexcitation of the carbonyl groups involved in lignin (Scheme 1) [4].

A Study of Sulfur-Bridge Structures in the Vulcanizates of EPDM Rubber by Pyrolysis-Gas Chromatography.

Sulfur-bridge structures in vulcanizates of EPDM rubber cured with sulfur tagged accelerators as 2-mercaptoben-zotiazole (MBT), tetramethylthiuram-monosulfide (TMTM) and tetramethylthiuram-disulfide (TMTD) were studied by pyrolysis gas chromatography (Py-GC) with a sulfur selective flame photometric detector(FPD). Two kinds of sulfur containing products such as C7H6S(I)(II) were typically observed on the pyrolysis gas chromatogram(pyrogtoram). These products might be assigned for 2, 4-cyclopenta[2, 3-b]thiophene and 2, 5-cyclopenta[2, 3-b]thiophene and supposed to be formed from sulfur bridges to ethylidene-norbornene residues in the polymer chain through cyclization. The vulcanization process for EPDM rubbers was discussed on the basis of relationships between the relative yield of C7H6S(I) (II) and curing times. The chemical mechanisms of formation of sulfur-bridges were also discussed on the basis of the observed pyrograms at the beginning of curing times.