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. Issue 20 (2nd August 2017)

• Record Type: Journal Article
• Authors: Tsuji, Hideto; Sakamoto, Yuzuru; Arakawa, Yuki
• Is Part Of: Macromolecular chemistry and physics. Volume 218:Issue 20(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-08-02
• Subjects: branched polymer -- phase transition -- poly(lactic acid) -- stereocomplex crystallization -- stereo‐specific polymers; Polymers -- Periodicals; Polymerization -- Periodicals; Synthetic products -- Periodicals; Macromolecules -- Periodicals; 547.7
• DOI: 10.1002/macp.201700286
• Languages: English
• ISSNs: 1022-1352

Abstract

Abstract: 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 ( T c ), and number‐average molecular weight ( M n ) 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 M n values, irrespective of arm number. For isothermal crystallization, the transition T c ranges below which in addition to SC crystallites, homo‐crystallites are formed depended on M n per one arm‐determining melting temperature or thickness of homo‐crystallites. The transition M n 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. Abstract : For isothermal crystallization, the transition crystallization temperature ranges below which in addition to stereocomplex crystallites, homo‐crystallites are formed depended on number‐average mole­­cular weight (Mn ) per one arm‐determining melting temperature or thickness of homo‐crystallites. The transition Mn ranges above which in addition to stereocomplex crystallites, homo‐crystallites are formed are not affected by arm number.