HU Lian-chun Kyoto Institute of Technology, Center for Environmental Science, Instructor, 環境科学センター, 教務職員 (60273546)
YOSHIDA Eri Kyoto Institute of Technology, Department of Polymer Science and Engineering, As, 繊維学部, 助手 (60263175)
|Budget Amount *help
¥3,100,000 (Direct Cost : ¥3,100,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1996 : ¥2,400,000 (Direct Cost : ¥2,400,000)
When blended with Nylon 6 (Ny6) and dipped in aqueous solutions, the polymers bearing ester-linkages in their repeating unit, i.e., poly (lactic acid), PMMA etc, can significantly enhance the decomposition rate of the entire blend systems. The hydrolysis of the blends was interpreted in terms of the following 5 stage mechanism : 1) sorption of water in Ny6,2) diffusion of water to the interfacial region between both components, 3) generation of -COOH groups due to the dissociation of estet-linkages, 4) formation of protons from -COOH,and 5) Proton catalytic depolymerization of Ny6.
If this postulated mechanism is right, it is very reasonable to predict that the use of more compatible co-component polymers with ester groups in their backbone and/or pendant chains should facilitate the decomposition of the blends. In the present study Ny6-block-PLA (BP), copoly (MMA-ran-acrylamide) (CPMA) and copoly-(MMA-N,N-dimethyl acrylamide) (CPMD) were subjected to blend with Ny6 in place of PLA and
PMMA on the basis of this hypothesis.
80 parts of Ny6 and 20 parts of PLA were melt-reacted in the presence of 1wt% of anhydrous zinc acetate in a twin-screw extruder with excellent mixing efficiency to prepare BP.Various CPMA and CPMD,different in monomeric composition, were also prepared by a conventional radical polymerization. 10 parts of each copolymer, BP,CPMA,or CPMD,was melt-brended with 90 parts of Ny6 in a laboratory kneader and cast into thin films in a hot-press. Several pieces of a rectangular specimens were cut out from the films thus prepared were immersed in a known volume of distillled water or a phosphate buffer solution with pH7. The changes in molecular weight, specimen mass, as well as mechanical properties were monitored during the hydrolysis.
It was concluded that the use of all the co-component is much more effective in the hydrolysis of resultant blends than their homopolymers, evaluated from the decreasing rate of molecular weight, specimen mass, and mechanical properties. In addition, the UV-spectroscopy of immersing solution, and FT-IR and NMR analyzes for the water soluble products separated from the aqueous media gave some strong evidences which support these copolymers blended in Ny6 matrices could facilitate the entire blend system.