中科院蘭州化學物理研究所先進潤滑與防護材料研發中心在形狀記憶聚合物研究方面取得新進展。
研究人員合成了系列含偶氮形狀記憶聚氨酯(azoPU)並研究了其光致異構作用。結果表明作為硬段的偶氮苯的加入,由於增加了聚氨酯的硬度及內部結合力誘導偶極-偶極作用引起的相分離的增加,能夠得到良好的機械性能、形狀固定率和形狀回復率(接近99.9%)。紫外-可見光譜表明,該聚氨酯在氯仿溶液和薄膜狀態下均能夠發生光致異構化作用。
該工作有望擴展形狀記憶聚氨酯在藥物釋放和光信息存儲等領域的應用。
由可逆相和固定相構成的形狀記憶聚氨酯(SMPU) 由於其生物相容性、生物降解和可控轉變溫度,在智能材料領域(如生物、醫藥和仿生)具有廣泛的應用前景。通過在聚合物中引入特殊功能的軟段或硬段,可設計形狀記憶聚合物使其多功能化。
該研究得到了國家自然科學基金委創新研究群體科學基金、中科院知識創新工程重要方向項目、國家重點基礎研究發展規劃的資金支持。
含偶氮苯聚氨酯的形狀記憶效應:(a)25℃下的原始形變;(b)75℃下拉伸後25℃固定的暫時形變;(c)加熱至75℃後回復到原始形變
研究結果發表在J. Mater. Chem. (J. Mater. Chem., 2010, 20, 9976–9981)。(生物谷Bioon.com)
生物谷推薦原文出處:
J. Mater. Chem. DOI: 10.1039/C0JM01944E
Shape memory polyurethanes containing azo exhibiting photoisomerization function
Yaoming Zhang, Chao Wang, Xianqiang Pei, Qihua Wang and Tingmei Wang
Abstract
A series of azobenzene-containing polyurethanes (azoPU) was synthesized. The structure of the azoPU and the synthesis process were detected by FTIR and nuclear magnetic resonance (NMR), and the transition temperature was determined by differential scanning calorimetry (DSC). Tensile and cyclic thermomechanical experiment results revealed that excellent mechanical properties, shape fixity (Rf), and shape recovery (Rr) were obtained by the addition of azo to the chain of PU. Rr and Rf of azoPU increased with the increase of hard segment (HS) content. The higher HS content enhanced interaction among polymer chains as the chances of induced dipole–dipole interaction between aromatic rings increased in the presence of azo in the main chain. The materials presented trans-cis isomerization under UV irradiation in addition to the shape memory effect. The UV-vis spectrum indicated that photoisomerization occurred both in solution and solid state. It is expected that the work may be helpful in expanding the application of shape memory PU in areas of drug release and optical data storage.