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-poly(NIPAM-
-HEMA) graft copolymersQuynh, T. M.*; Yoneyama, Masaru*; Maki, Yasuyuki*; Nagasawa, Naotsugu; Dobashi, Toshiaki*
Key Engineering Materials, 459, p.51 - 56, 2010/12
Times Cited Count：3 Percentile：81.92(Engineering, Electrical & Electronic)Different poly(
-isopropylacrylamide-
-hydroxyethyl methacrylate) copolymers [P(NIPAM--HEMA)] were synthesized from -isopropylacrylamide (NIPA) and hydroxyethyl methacrylate (HEMA) monomers by both radical and radiation polymerizations for comparison. PLLA-
-P(NIPAM--HEMA) graft copolymers were synthesized from L-lactide and respective P(NIPAM--HEMA) copolymers by ring opening polymerization. Both NMR and FTIR analyses demonstrated the PLLA chains have been grafted on to the P(NIPAM--HEMA) backbone. These graft copolymers revealed the cloud point temperature higher than that of PNIPAM homopolymer as determined by optical transmittance. The graft copolymers self-assembled into micelles with regularly spherical structures as observed by atomic force microscopy (AFM). The properties of these graft copolymers are interesting for the drug delivery system.
Quynh, T. M.*; Mitomo, Hiroshi*; Nagasawa, Naotsugu; Wada, Yuki; Yoshii, Fumio; Tamada, Masao
European Polymer Journal, 43(5), p.1779 - 1785, 2007/05
Times Cited Count：115 Percentile：95(Polymer Science)Crosslinked materials derived from poly(lactide) (PLA) have been produced by radiation modification in the presence of a suitable crosslinker (triallyl isocyanurate: TAIC). The crosslinking structure introduced in PLA films has not only much improved the heat stability but also their mechanical properties. The properties of crosslinked samples are governed by crosslinking density and these improvement seemed to increase with radiation dose. This implied that the three dimensional networks have been introduced in material by radiation and the crosslinking density depended on the structure and length of PLA chains. Biodegradability of PLA was also determined by an enzymatic degradation test and burying in compost at 55 
C. Differing with PLLA, PDLA was insignificantly degraded by 
. The degradation rate of PLA in compost was postponed with the introduction of crosslinks.
Nagasawa, Naotsugu; Kaneda, Ayako*; Matsuzaki, Tomoaki*; Kanazawa, Shinichi*; Yagi, Toshiaki; Tran, M. Q.*; Mitomo, Hiroshi*; Yoshii, Fumio; Tamada, Masao; Quynh, T. M.*
JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 53, 2007/02
Poly(L-lactic acid), PLA was irradiated using electron beams (EB) in the presence of polyfunctional monomers (PFM) as crosslinking agent. Among the PFMs, triallyl isocyanurate (TAIC) at 3% concentration was found to be the most effective for crosslinking of PLA by irradiation technique. The crosslinked PLA obtained has heat resistance higher than 200C. From this fact, the crosslinked PLA is applied on heat-shrinkable tube, cup and plate. The shrinkable tube has several advantages such as high heat resistance and transparency. It is therefore proven that crosslinking technology is beneficial to expanding the application of PLA.
Nagasawa, Naotsugu; Yagi, Toshiaki; Kanazawa, Shinichi*; Quynh, T. M.*; Mitomo, Hiroshi*; Yoshii, Fumio; Tamada, Masao
no journal, ,
no abstracts in English
Quynh, T. M.*; Nagasawa, Naotsugu; Nagai, Daisuke*; Yagi, Toshiaki; Tamada, Masao; Mitomo, Hiroshi*
no journal, ,
no abstracts in English
