Crystallization of Poly(-caprolactone) in Its Immiscible Blend with Polylactide: Insight into the Role of Annealing Histories
作者：Qiaolian Lv, Defeng Wu,* Hui Xie, Sheng Peng, Yang Chen, Chunjiang Xu
關鍵字：poly( -caprolactone); polylactide; blend; affinity; crystallization.
論文來源：期刊
具體來源：RSC Advances
發表時間：2016年
RSC Advances, 2016, 6(44), 37721-37730.
ABSTRACT:
Polylactide/poly(3-caprolactone) (PLA/PCL) is a very promising blend material with biodegradable characteristics and tailorable performance because of good property
complementarity between two components. However, PLA and PCL are asymmetric
thermodynamically: PLA has far higher melting point than PCL, and crystallization temperature of PCL is even lower
than glass transition temperature of PLA. But this also provides good
opportunity to control final structure and properties of PCL/PLA blends through
thermal annealing. In this work, two annealing routes were designed to control
supermolecular structure of discrete PLA phase in the PCL-rich blends, and the two systems, the blend with discrete amorphous PLA domains
and the one with discrete crystallized PLA phase, were obtained. The
interfacial property alteration and crystallization behavior of continuous PCL
phase were then studied. The results are very interesting. Relative to the
amorphous PLA phase, the crystallized PLA domains have better affinity to the
continuous PCL phase, showing stronger nucleating effect to the
crystallization of PCL and higher impeding effect on the shear flow of blend
system. But the presence of discrete PLA phase, whether in crystallized or
amorphous state, has no evident influence on the crystal structure and lamellar thickness of PCL. These effects on the
crystallization of PCL make the mechanical properties of blends very sensitive
to the annealing histories. The blend sample with the crystallized PLA domains shows higher modulus and
strength than the one with the amorphous PLA domains, and the values of modulus
and strength increase by about 130% and 43%, respectively, relative to the neat PCL. This work provides a facile and green approach to well
tailor the supermolecular structure and mechanical properties of the PCL/PLA blends
through the simple control of annealing process.
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