SYNTHESIS AND REDOX GELATION OF DISULFIDE-MODIFIED POLYOXAZOLINE
SYNTHESIS AND REDOX GELATION OF DISULFIDE-MODIFIED POLYOXAZOLINE
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DOI：
10.1021/ma00057a001
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发表时间：
1993-03-01
期刊：
影响因子：
5.5
通讯作者：
SAEGUSA, T
中科院分区：
文献类型：
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作者：
CHUJO, Y;SADA, K;SAEGUSA, T
通过巯基保护的聚（N-乙酰基乙烯亚胺）（PAEI）（蒽-SS-改性的PAEI）的还原-氧化或通过部分水解的PAEI与双官能二硫化合物的交联反应制备具有二硫桥的聚恶唑啉水凝胶。作为二硫化物交联剂，二硫代二-2，1 '-乙二基二异氰酸酯/1，8-二氮杂双环[5.4.0]十一碳-7-烯或3，3'-二硫代丙酸/二环己基碳二亚胺给出了良好的结果。巯基保护的PAEI经还原得到巯基修饰的PAEI，其易于被空气氧化形成网络。这些基于高度亲水性PAEI的凝胶是稳定的，并且作为水凝胶在水中溶胀。制备了一系列具有不同量的官能团的PAEI，并通过还原-氧化进行交联反应。在水中的溶胀度的增加与预聚物中的取代度的降低。通过用还原剂如连二亚硫酸钠、硼氢化钠或三苯基膦处理，二硫化物桥接的PAEI凝胶变得可溶以形成线性聚合物。凝胶的这种增溶作用是由交联点处二硫桥的还原裂解引起的。这种从水凝胶到可溶性聚合物的相互转化可以被认为是一种新型的氧化还原可逆的水凝胶系统，其通过二硫化物和硫醇基团之间的可逆转化。
A polyoxazoline hydrogel having a disulfide bridge was prepared by the reduction-oxidation of thiol-protected poly(N-acetylethylenimine) (PAEI) (anthracene-SS-modified PAEI) or by the cross-linking reaction of the partially hydrolyzed PAEI with bifunctional disulfide compounds. As a disulfide cross-linking agent, dithiodi-2,1'-ethanediyl diisocyanate/1,8-diazabicyclo[5.4.0] undec-7-ene or 3,3'-dithiopropanoic acid/dicyclohexylcarbodiimide gave good results. The reduction of thiol-protected PAEI produced the thiol-modified PAEI, which was susceptible to air oxidation to form the networks. These gels based on highly hydrophilic PAEI were stable and swollen in water as a hydrogel. A series of PAEIs having varying amounts of the functional groups were prepared and subjected to cross-linking reactions by reduction-oxidation. The degree of swelling in water increased with a decrease of the degree of substitution in the prepolymer. The disulfide-bridged PAEI gel became soluble to form the linear polymer by the treatment with reducing agents such as sodium hydrosulfite, sodium borohydride, or triphenylphosphine. This solubilization of gel was caused by the reductive cleavage of the disulfide bridge at the cross-linking points. This interconversion from a hydrogel to a soluble polymer can be regarded as a novel redox-reversible hydrogel system by means of reversible conversion between disulfide and thiol groups.