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Tago, Takanori; Nagasawa, Naotsugu; Tamada, Masao; Kudo, Hisaaki*; Katsumura, Yosuke*
no journal, ,
no abstracts in English
Tago, Takanori; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Kudo, Hisaaki*; Katsumura, Yosuke*
no journal, ,
no abstracts in English
Tago, Takanori; Nagasawa, Naotsugu; Taguchi, Mitsumasa; Tamada, Masao; Kudo, Hisaaki*; Katsumura, Yosuke*
no journal, ,
Poly (L-lactic acid) (PLA) derived from corn starch is now widespread with a potential to replace the conventional petroleum-derived plastics. The PLA has, however, the less thermal stability above around 60
C and impact resistance at room temperature than the conventional plastics. In this study, to improve the above-mentioned two properties of PLA, we investigated a new combination method of blending with polyamide11 (PA11) having high impact resistance, which is derived from castor oil, and then crosslinking. PLA/PA11(50/50wt%) blend with 3 phr of crosslinker irradiated to 100 kGy was formed about 80% of gel content. This sample demonstrated very little deformation above the grass transition-temperature of PLA, the melting-temperature of PLA and PA11 (ca.175C and 185C, respectively) by thermal-mechanical analysis. The impact value of crosslinked PLA/PA11 blend is 4.8 kJ/m
. This value showed higher about 2.5 times of original PLA. Therefore, the applications of bioplastics will be expanded.
Tago, Takanori; Nagasawa, Naotsugu; Kudo, Hisaaki*; Taguchi, Mitsumasa; Katsumura, Yosuke*
no journal, ,
Poly (L-lactic acid)(PLA) is a hard and transparent bioplastic and now widespread with a potential to replace the conventional petroleum-derived plastics. The PLA crosslinked to improve the thermal property by irradiating with triallyl isocyanurate (TAIC). The impact resistance, however, is nearly un-improved. To improve the above-mentioned two properties of PLA, we investigated a new combination method of blending of PLA with polyamide11 (PA11) having high impact resistance, which is produced from castor oil, and then crosslinking with TAIC by radiation. The crosslinking structures were formed in irradiated PLA/PA11 blends with TAIC. The gel content of PLA/PA11 blends increased with increasing the mixing ratio of PA11 and absorbed dose. At the dose of 100 kGy and more, the network was formed about 80% in the PLA / PA11 blends. The thermal properties of the blends were evaluated from the deformation at the melting-temperature (
) by the thermo-mechanical analysis. The blends with high gel contents (
80%) demonstrated very little deformation above the of PA11 around 185C. The improvement of the impact property was indicated by the Charpy impact testing. The blends (50/50wt%) irradiated with 100 kGy showed the higher impact resistance about 2.5 times of original PLA. Therefore, the applications of bioplastic will be expanded by the combination method of blending and radiation-induced crosslinking.
Nagasawa, Naotsugu; Tago, Takanori*; Kudo, Hisaaki*; Tamada, Masao; Katsumura, Yosuke; Taguchi, Mitsumasa
no journal, ,
Polyamide11, (PA11) or Nylon 11 is one of polyamide bioplastics derived from castor beans oil. PA11 has excellent properties such as superior thermal resistance, chemical resistance, good flexibility and good impact resistance. Radiation-induced crosslinking is an effective method to improve the thermal stability of polymers. It was found that poly(L-lactic acid) (PLLA) which is other bioplatic derived from renewable resources such as sugar or corn starch, has improved the heat resistance property by radiation-induced crosslinking with triallyl isocyanurate (TAIC). PA11 is a most promising candidate for blending material of PLLA to improve the brittleness and lack of flexibility of the PLLA. In this study, to improve the above-mentioned two properties of PLLA, we investigated radiation-induced crosslinking of PA11 with TAIC in order to obtain a basic knowledge about production of blend material of PLLA and PA11. The crosslinking structures were formed in irradiated PA11 without and with TAIC. The gel content of PA11 increased with the absorbed dose and additive concentration of TAIC. The gel fraction of PA11 without TAIC is about 9.7% at irradiation dose of 200 kGy, 39.9% at 300 kGy, 60.3% at 500 kGy, respectively, and saturated to 76.2% at even higher than 750 kGy. Although no gelation was observed below 190 kGy. For TAIC added PA11, the gel content increased significantly at the lower dose of 200 kGy. The network was formed about 85% in 3 phr (per hundred resin) TAIC added PA11 samples at the dose of 10 kGy. The thermal properties of the samples were evaluated from the deformation at the Tm evaluated by the thermo-mechanical analysis. The TAIC added PA11 with high gel contents ( 80%) by irradiation demonstrated very little deformation above the Tm of PA11 around 185 C. Therefore, the applications of bioplastic will be expected expanding by the radiation-induced crosslinking.