Highly Reinforced Poly(lactic acid) Foam Fabricated by Formation of a Heat-Resistant Oriented Stereocomplex Crystalline Structure
Highly Reinforced Poly(lactic acid) Foam Fabricated by Formation of a Heat-Resistant Oriented Stereocomplex Crystalline Structure
复制标题
DOI：
10.1021/acssuschemeng.1c04862
复制
发表时间：
2021-09
影响因子：
8.4
通讯作者：
Ruiguang Li;Xiaowen Zhao;P. Coates;Fin Caton-Rose;L. Ye
中科院分区：
文献类型：
--
作者：
Ruiguang Li;Xiaowen Zhao;P. Coates;Fin Caton-Rose;L. Ye
Avoiding disorientation of oriented poly(l-lactide) (PLLA) during foaming remains challenging for preparing highly reinforced PLLA foams with an oriented structure. By utilizing the melting-temperature difference of stereocomplex (SC)/homo-crystallite (HC) crystals, PLLA/poly(d-lactide) (PDLA) blend foams with an oriented crystalline structure were prepared via solid-phase hot drawing and the supercritical CO2foaming technology. Incorporating both SC crystals and molecular orientation promoted PLLA crystallization, and highly oriented HC/SC crystals formed after drawing. By subsequent foaming, HC crystals mainly formed. For the oriented pure PLLA sample, serious disorientation occurred after foaming, while for the oriented PLLA/PDLA blend foam, with increasing PDLA content, orientation retention of the HC/SC crystal increased sharply to 70.4/87.8%. Much more fibrillar structures formed on the cell wall of foams, indicating that forming the SC crystal was significant to maintain the orientation structure of PLLA during foaming. By increasing the PDLA content and draw ratio, the dissolved CO2amount increased, while CO2escape was hindered, resulting in a dense cell structure. Highly oriented PLLA/PDLA foams exhibited superior heat resistance and mechanical strength.
