School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China.
School of Materials Science and Engineering, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China.
Int J Biol Macromol. 2021 Dec 15;193(Pt B):1685-1693. doi: 10.1016/j.ijbiomac.2021.10.227. Epub 2021 Nov 6.
With the increasingly serious plastic pollution, people's demand for the multi-functional biodegradable plastics is becoming more and more urgent. Inspired by the crosslinked shape memory polymers, the crosslinked starch films were synthesized by inducing the decomposition of benzophenone into free radical and depriving hydrogen on starch macromolecules under UV irradiation, in order to gain a high shape memory performance. The results showed that a three-dimensional crosslinking network between starch macromolecule chains was formed. Compared with the uncrosslinked starch films, the photo-crosslinked films not only had higher mechanical property (tensile strength increased by 154%), but also had better water resistance (water contact angle from 60° to 87°) due to the reduction of free hydroxyl groups. In addition, the stable covalent bonds serving as netpoints endow photo-crosslinked films with great improvement in shape memory property, with nearly 180° bending recovery. More importantly, the maximum shape memory fixity ratio (R) and shape memory recovery ratio (R) under stretch deformation were 96.5% and 99.8%, respectively. And the R and R could reach 94.6% and 79.8% even at higher strain. In all, the excellent shape memory performance and good degradability crosslinked starch films, which have great potential application in disposable heat-shrinkable packaging materials.
随着塑料污染的日益严重，人们对多功能可生物降解塑料的需求变得越来越迫切。受交联形状记忆聚合物的启发，通过在紫外光照射下诱导二苯甲酮分解为自由基并从淀粉大分子上剥夺氢，合成了交联淀粉薄膜，以获得高形状记忆性能。结果表明，在淀粉大分子链之间形成了三维交联网络。与未交联的淀粉薄膜相比，光交联薄膜不仅具有更高的机械性能（拉伸强度提高了 154%），而且由于游离羟基的减少，还具有更好的耐水性（水接触角从 60°变为 87°）。此外，作为网络点的稳定共价键赋予光交联薄膜在形状记忆性能方面的巨大改善，可实现近 180°的弯曲恢复。更重要的是，在拉伸变形下，最大形状记忆固定比（R）和形状记忆恢复比（R）分别达到 96.5%和 99.8%。即使在较高的应变下，R 和 R 也分别可以达到 94.6%和 79.8%。总之，交联淀粉薄膜具有优异的形状记忆性能和良好的可降解性，在一次性热收缩包装材料中具有巨大的潜在应用前景。
