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·428·                             精细化工   FINE CHEMICALS                                  第 36 卷

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            拉伸、打结、扭转等一系列的变形。考虑到离子键                             MA。对于 AAc 和 IA 体系,当—COO 含量为 25%,
                                                                                    
                                                                       3+
            的动态特点,研究了水凝胶的自愈合特性,结果如                             并且 n(Fe )∶n(—COO )=8∶1 时,水凝胶拉伸强度
                                                                                             
                                                                                 3+
            图 8d~g 所示。将制备好的 DN 水凝胶用手术刀切成                       达到最大值,当 n(Fe )∶n(—COO )<8∶1 时水凝胶
            两部分(图 8d),对接用保鲜膜裹住防止水分流失。                          交联网络结构不完善,高于 8∶1 时交联过于致密。
            放置 16 h 后可以看到虽然凝胶样条被宏观破坏,但
                                                               参考文献:
            是界面之间的接触将使水凝胶自发愈合(图 8e)。
                                      3+
            这表明凝胶体系中游离的 Fe 可以运动和迁移,从                           [1]   Vlierberghe S, Dubruel P, Schacht E. Biopolymer-based hydrogels as
                                                                   scaffolds  for  tissue  engineering  applications:  A  review[J].
            而重新交联聚合物侧链上的羧基,使凝胶具有自愈                                 Biomacromolecules, 2011, 12 (5): 1387-1408.
                   [9]
            合行为 。从图 8e 可以看出,愈合后的水凝胶可以                          [2]   Lin  C,  Metters  A.  Hydrogels  in  controlled  release  formulations:
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            承受水凝胶自身的重量;从图 8f 可以看出,愈合后                              Delivery Reviews, 2006, 58(12/13): 1379-1408.
            的水凝胶还可以承受 200 g 的砝码;进一步测试可知,                       [3]   Xie Biaoming (谢标明), Zhu Hekang (朱和康), Yang Yue (杨越), et
                                                                   al.  Synthesis  of  poly(acrylic  acid)/graphene  oxide  composite
            愈合后的水凝胶最大可承受 1.055 kg 的载荷(图 8g)
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            (对应的拉力为 10.35 N,强度为 0.13 MPa)。                         Fine Chemicals (精细化工), 2018, 35(1): 108-117.
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                      图 8    水凝胶的变形及自愈合特性                          Applied Materials & Interfaces, 2013, 5(21): 10418-10422.
            Fig. 8    Deformation and self-healing properties of hydrogel   [9]   Wei Z, He J, Liang T, et al. Autonomous self-healing of poly(acrylic
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            节羧基单体和离子种类与浓度制备了拉伸强度超过                             [12]  Li Laimming (李来明), Zeng Guangfu (曾广赋), Zhuang Wende (庄
                                      3+
            6.0 MPa 的 D-PAM-PAAc-Fe 水凝胶,该水凝胶具                      文德), et al. Infrared spectra of some rare earth propionates[J]. Acta
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            有很好的塑形性,能够承受拉伸、打结、扭转等一                             [13]  Liu  Guangdong  (刘光冬),  Li  Yuliang  (李玉良). Effect  of some
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                 (2)离子键数量显著影响水凝胶的强度。单网                             Sinica (高分子学报), 1990, 1(2): 136-141.
                                                        2+
            络水凝胶网络结构不均一,因此强度较低;而 Ca 、                          [14]  Tobolsky  A,  Carlson  D,  Indictor  N.  Rubber  elasticity  and  chain
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                              
              2+
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            Fe 、Cu 与—COO 双齿鳌合,网络结构均一性提                         [15]  Gao Tingting (高婷婷), Li Zhiying (李志英), Gao Ge (高歌), et al.
                                                3+
            高,网络尺寸减小,强度有所提高;Fe 与—COO                              Mechanical  strength  and  swelling  behavior  of  fatty  alcohol
            主要以三齿鳌合为主,水凝胶网络更均匀和致密,因                                polyoxyethylene  acrylate  hydrophobic  associated  hydrogels[J].
                                                                   Chemical  Journal  of  Chinese  Universities  (高等学校化学学报),
                     3+
            此浸泡 Fe 之后有效交联密度 v 0 增大,而交联点之                           2016, 37(9): 1744-1749.
            间的相对分子质量 M c 减小,使单网络水凝胶拉伸强                         [16]  Chattopadhyay S, Singhal R, Kulkarni P. Optimisation of conditions
                                                                   of  synthesis  of  oxidised  starch  from  corn  and  amaranth  for  use  in
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                        3+
                 (3)Fe 与羧基形成离子键存在依时性,随着                            203-212.
            离子浓度以及浸泡时间的延长,拉伸强度先增加,                             [17]  Yang  Y,  Wang  X,  Yang  F,  et al.  A  universal  soaking  strategy  to
                                                                   convert  composite  hydrogels  into  extremely  tough  and  rapidly
                       3+
            当羧基与 Fe 配位达到饱和时强度趋于恒定。                                 recoverable double-network hydrogels[J]. Advanced Materials, 2016,
                 (4)AAc 和 IA 所得 DN 水凝胶由于水凝胶中                       28(33): 7178-7184.
                                                               [18]  Hong  Ying  (洪盈).  Organic  Chemistry  (2rd)[M].  Beijing:People's
            羧基含量多,和金属离子形成离子键的数量较多,                                 Medical  Publishing  House  Press  (北京:人民卫生出版社),  1990:
            其有效交联密度 v 0 较大,因此水凝胶力学性能优于                             86-87.
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