Sen'i Gakkaishi

Degradation behavior of polyester fibers was examined in compost, using polyethylene terephthalate (PET) and Ecoface® that has a modified PET structure with partly introduced hydrolyzable groups. Both (as knit articles and cloth) showed gradual decrease of the molecular weights in compost. The decrease of molecular weights of Ecoface® reached around 90% after ca. 6 months, but that of PET remained less than 50%. Although decrease of a molecular weight of PET cloth was observed, no fragmentation was found after ca. 6 months with and without inoculum of actinomycetes. Thin cloth of Ecoface® showed ca. 90% decrease in its molecular weight after 3 months and was fragmented. Even thick cloth of Ecoface® showed fragmentation after ca. 4.5 months with ca. 90% decrease of the original molecular weight. Fragmentation seemed to be caused when the decrease of a molecular weight reached over 90%. Inoculation of polyester-degrading thermophilic actinomycetes on the surface of samples seemed to promote and stabilize degradation of Ecoface® fragmented in compost.

View full abstract

Thermoplasticization of lignin was achieved by the acylation of polyfunctional lignin yielded in the course of the alkali cooking of wood tips. The kneading of acylated lignin and poly(ε-caprolactone) gave the composite film with reasonable flexibility and light blocking property which might provide several utilization ways of lignin to serve as substitution of petroleum products. The un-acylated (virgin) lignin also gave flexible, thermoplastic composites with polypropylene (PP) when maleate-modified PP co-existed.

View full abstract

Show abstractHide abstract

This study compared various sizing evaluation tests, including the Stöckigt and Cobb tests as the most popular methods, by using papers of varied basis weight and varied dose of sizing agent. Many tests, including Stöckigt, Hercules, KBB and Cobb, are severely affected by basis weight. None of these except Cobb are sufficiently sensitive to evaluate light sizing, because they measure water penetration in the Z-direction and the distance is quite small. The Klemm test, which has been used for water absorptiveness of non-sized paper, determines the absorptiveness in the X-Y direction and is sufficiently sensitive to evaluate even light sizing as an absolute sizing degree. The interconnected pore structure of paper makes the absorptiveness in the X-Y direction equivalent to that in the Z-direction. The Standard Klemm test gives the absorptiveness height for 10 min testing and is independent of basis weight. A shorter testing time than 10 min could be used but the absorptiveness height is too small to detect for heavy sizing. Further, the heading edge of water uptake is often vague, and thus the absorptiveness height can be replaced by the weight increase due to water absorption (absorptiveness weight) as a more accurate measure. Furthermore, the absorptiveness weight measured by the Klemm test which was linearly proportional to basis weight could be normalized with basis weight and specimen width (1.5 cm), and thus was indicated as absorptiveness height. This test was proposed as an absolute evaluation for sizing degree (Klemm test for sizing evaluation) in this report because it is independent of basis weight and is sensitive enough to measure sizing degree accurately even with light sizing.

View full abstract

Download PDF (1368K)

Register with J-STAGE for free!