Zhang Jiuyang, Li Tuoqi, Mannion Alexander M, Schneiderman Deborah K, Hillmyer Marc A, Bates Frank S
Department of Chemical Engineering and Materials Science and ‡Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States.
Department of Chemical Engineering and Materials Science and Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States.
ACS Macro Lett. 2016 Mar 15;5(3):407-412. doi: 10.1021/acsmacrolett.6b00091. Epub 2016 Mar 4.
Fully sustainable poly[HPMC--(PMVL--PLLA)] graft block copolymer thermoplastics were prepared from hydroxypropyl methylcellulose (HPMC), β-methyl-δ-valerolactone (MVL), and l-lactide (LLA) using a facile two-step sequential addition approach. In these materials, rubbery PMVL functions as a bridge between the semirigid HPMC backbone and the hard PLLA end blocks. This specific arrangement facilitates PLLA crystallization, which induces microphase separation and physical cross-linking. By changing the backbone molar mass or side chain composition, these thermoplastic materials can be easily tailored to access either plastic or elastomeric behavior. Moreover, the graft block architecture can be utilized to overcome the processing limitations inherent to linear block polymers. Good control over molar mass and composition enables the deliberate design of HPMC--(PMVL--PLLA) samples that are incapable of microphase separation in the melt state. These materials are characterized by relatively low zero shear viscosities in the melt state, an indication of easy processability. The simple and scalable synthetic procedure, use of inexpensive and renewable precursors, and exceptional rheological and mechanical properties make HPMC--(PMVL--PLLA) polymers attractive for a broad range of applications.
采用简便的两步顺序添加法，由羟丙基甲基纤维素（HPMC）、β-甲基-δ-戊内酯（MVL）和L-丙交酯（LLA）制备了完全可持续的聚[HPMC-(PMVL-PLLA)]接枝嵌段共聚物热塑性塑料。在这些材料中，橡胶状的PMVL充当半刚性HPMC主链与硬PLLA端嵌段之间的桥梁。这种特殊排列促进了PLLA结晶，进而引发微相分离和物理交联。通过改变主链摩尔质量或侧链组成，这些热塑性材料可以轻松调整以实现塑性或弹性行为。此外，接枝嵌段结构可用于克服线性嵌段聚合物固有的加工限制。对摩尔质量和组成的良好控制能够精心设计在熔融状态下不会发生微相分离的HPMC-(PMVL-PLLA)样品。这些材料的特点是在熔融状态下具有相对较低的零剪切粘度，这表明其易于加工。简单且可扩展的合成方法、使用廉价且可再生的前体以及出色的流变学和机械性能，使得HPMC-(PMVL-PLLA)聚合物在广泛的应用中具有吸引力。
