Controlled crystal nucleation in the melt-crystallization of poly(l-lactide) and poly(l-lactide)/poly(d-lactide) stereocomplex
Controlled crystal nucleation in the melt-crystallization of poly(l-lactide) and poly(l-lactide)/poly(d-lactide) stereocomplex
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DOI：
10.1016/s0032-3861(03)00583-4
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发表时间：
2003-09
期刊：
影响因子：
4.6
通讯作者：
H. Urayama;T. Kanamori;K. Fukushima;Y. Kimura
中科院分区：
文献类型：
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作者：
H. Urayama;T. Kanamori;K. Fukushima;Y. Kimura
在各种无机成核剂检查，滑石粉和铝配合物的磷酸酯结合水滑石（NA）被发现是有效的熔融结晶的聚（L-丙交酯）（PLLA）和PLLA/聚（D-丙交酯）（PDLA）立体混合物，分别。NA（1.0phr/100树脂）仅能使PLLA和PDLA的晶体成核，而滑石粉不能抑制PLLA和PDLA的均相结晶。滑石粉和NA（各1.0phr）的双重使用对于提高立体复合物的结晶温度而不形成均晶是非常有效的。通过NA成核的立体复合物晶体显示出比立体复合物的单晶（230 °C）显著更低的熔融温度（207 °C），尽管记录了大的结晶热ΔHc（54 J/g）。光学显微镜研究表明，具有对称形态的球晶形成在添加NA的立体混合物中，而球晶的大小不增长在添加滑石粉的混合物中。通过熔融-结晶过程的立体复合物晶体的排他性生长将为PLLA/PDLA打开加工窗口。
Among the various inorganic nucleators examined, Talc and an aluminum complex of a phosphoric ester combined with hydrotalcite (NA) were found to be effective for the melt-crystallization of poly(l-lactide) (PLLA) and PLLA/poly(d-lactide) (PDLA) stereo mixture, respectively. NA (1.0phr (per one hundred resin)) can exclusively nucleate the stereocomplex crystals, while Talc cannot suppress the homo crystallization of PLLA and PDLA in the stereo mixture. Double use of Talc and NA (in 1.0phr each) is highly effective for enhancing the crystallization temperature of the stereo complex without forming the homo crystals. The stereocomplex crystals nucleated by NA show a significantly lower melting temperature (207 °C) than the single crystal of the stereocomplex (230 °C) in spite of recording a large heat of crystallization ΔHc(54 J/g). Photomicrographic study suggests that the spherulites with a symmetric morphology are formed in the stereo mixture added with NA while the spherulites do not grow in size in the mixture added with Talc. The exclusive growth of the stereocomplex crystals by the melt-crystallization process will open a processing window for the PLLA/PDLA.