Stereocomplex- and Homo-Crystallization and Phase-Transition Behavior of Relatively High-Molecular-Weight Linear One- and Two-Armed and Star-Shaped Four-Armed Poly(l-lactide)/Poly(d-lactide) Blends
Stereocomplex- and Homo-Crystallization and Phase-Transition Behavior of Relatively High-Molecular-Weight Linear One- and Two-Armed and Star-Shaped Four-Armed Poly(l-lactide)/Poly(d-lactide) Blends
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DOI：
10.1002/macp.201700286
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发表时间：
2017-08
影响因子：
2.5
通讯作者：
H. Tsuji;Yuzuru Sakamoto;Y. Arakawa
中科院分区：
文献类型：
--
作者：
H. Tsuji;Yuzuru Sakamoto;Y. Arakawa
合成了相对高分子量的直链单臂、双臂和星形四臂聚丙交酯，并研究了臂数（支化结构、共引发剂结构）、结晶温度（Tc）和数均分子量（Mn）对立体复合物（SC）和均相结晶及相变行为的多重影响。对于非等温和等温结晶，除了SC微晶，均质微晶形成在具有较高的Mn值的共混物中，与臂数无关。对于等温结晶，转变Tc的范围低于除了SC微晶，均质微晶形成取决于Mn每一个臂确定熔化温度或厚度的均质微晶。除了SC微晶之外，形成均质微晶的过渡Mn范围不受臂数的影响。高分子量干扰了单臂和双臂共混物晶体生长机制的变化，而支化结构抑制了四臂共混物晶体生长机制的变化。
Relatively high-molecular-weight linear one- and two-armed and star-shaped four-armed poly(l-lactide) and poly(d-lactide) are synthesized and the multiplicate effects of arm-number (branching architecture, coinitiator moiety), crystallization temperature (Tc), and number-average molecular weight (Mn) on stereocomplex (SC)- and homo-crystallization and phase-transition behavior are investigated. For nonisothermal and isothermal crystallization, in addition to SC crystallites, homo-crystallites are formed in the blends with higher Mn values, irrespective of arm number. For isothermal crystallization, the transition Tc ranges below which in addition to SC crystallites, homo-crystallites are formed depended on Mn per one arm-determining melting temperature or thickness of homo-crystallites. The transition Mn ranges above which in addition to SC crystallites, homo-crystallites are formed are not affected by arm number. The high molecular weight disturbs the change of crystalline growth mechanism of one- and two-armed blends, whereas the branching architecture inhibits the change of crystalline growth mechanism of four-armed blends.