基于双硫键的自修复聚氨酯研究进展

归纳了基于双硫键的自修复聚氨酯的制备方法、自修复机理和过程以及相应的表征手段;总结了双硫键自修复聚氨酯在自修复效率、相关结构和力学性能等方面的研究状况,展望了其发展前景,指出了其研究方向。     

一种基于动态双硫键的自修复聚氨酯弹性体的制备与性能

以聚丙二醇(PPG)、异佛尔酮二异氰酸酯(IPDI)和含硫扩链剂胱氨酸二甲酯(CDE)为原料,固定摩尔比为1∶3∶2,采用预聚体法制备含硫自修复聚氨酯弹性体(SPU),对SPU进行红外光谱测试、拉曼光谱测试、力学性能和自修复性能测试、划痕修复观察和DSC测试。结果表明,SPU为非晶结构,微相分离程度低;切割50%深度后,通过拉伸强度测试得出其在60℃的自修复效率达到89.8%,原因是动态双硫键的交换反应和分子链的高运动能力(硬段玻璃化转变温度<60℃)。     

基于双硫键自修复高分子材料研究进展

自修复高分子材料是一种采用仿生思想制备的高分子材料,即当基体受损时能够在一定条件下实现自我修复。自修复高分子材料可分为外援型和本征型两种,本文重点介绍基于双硫键本征型自修复高分子材料的研究进展。综述了近年来国内外制备双硫键自修复高分子材料的方法及其修复机理,并对未来研究及发展进行了展望。     

双硫键和双硒键在自修复聚氨酯脲弹性体中的应用

为解决自修复聚氨酯脲(PUU)弹性体兼具高修复效率和优异力学性能的问题,提出在PUU弹性体主链引入动态双硫键或双硒键。以聚碳酸酯二醇(PCDL)为软段,异佛尔酮二异氰酸酯(IPDI)为硬段,分别以胱胺(CY)、硒代胱胺(SeCY)和1,6-己二胺(HDA)为扩链剂,通过溶液法制备3种PUU弹性体,即含动态双硫键的PUU试样(SPU)、含动态双硒键的PUU试样(SePU)和对照组PUU试样(CPU)。通过红外、X射线衍射、拉伸测试、光学显微、热分析等对3种试样的结构和性能进行表征。结果表明,SPU的力学性能和自修复性能达到较好的平衡,拉伸强度和断裂伸长率分别达到53.1 MPa和400.5%,80℃修复12 h后的自修复效率分别为87.2%和75.7%;SePU具有最优的自修复性能,80℃修复12 h后的自修复效率达到98.9%和95.3%。     

基于酚-氨基甲酸酯键的自修复聚氨酯的制备及其热降解性能

为制备既具有良好力学性能,又具有自修复性能的聚氨酯材料,以不同比例的异佛尔酮二异氰酸酯和聚四氢呋喃二醇为原料制备了异氰酸酯基封端的聚氨酯预聚体,随后以不同用量的对苯二酚为扩链剂,制备了两种含有“酚-氨基甲酸酯键”的聚氨酯材料(BPPU)。利用凝胶渗透色谱(GPC)、傅里叶变换红外光谱(FTIR)、热重仪(TG)、万能力学试验机等分析手段对制备的自修复聚氨酯进行了分析表征。结果表明,增大异氰酸酯基与聚四氢呋喃二醇羟基的物质的量比(R值)不仅有助于制备分子量更大的自修复聚氨酯,而且有助于提升聚氨酯的拉伸强度和耐热性,此外,两种含有“酚-氨基甲酸酯键”的聚氨酯均表现出了优异的自修复性能,而且当R=4.0时BPPU的自修复效率达到了93.8%,且两种BPPU在经历自修复历程后,其红外光谱的峰形和峰位置几乎没有变化。     

双硫键本征型自修复聚合物的研究进展

聚合物材料已应用于工业生产的各个领域,成为生产、生活中不可缺少的部分,然而聚合物材料会产生微损伤将直接缩短使用寿命及降低材料的性能。具有自诊断、自修复型功能聚合物材料,其包括包埋型和本征型两种自修复机理。基于双硫键自修复聚合物具有多次自修复功能,文章主要综述了国内外基于双硫键本征型自修复聚合物研究进展。     

基于双硫键和氢键协效的高性能自修复聚氨酯脲的研制

为解决自修复弹性体同时具有优异的力学性能和自修复性能的矛盾,首先将原料胱氨酸（CYS）进行甲酯化得到含双硫键的二胺扩链剂胱氨酸二甲酯（CDE）,然后以聚四氢呋喃醚二醇（PTMG）为软段,异佛尔酮二异氰酸酯（IPDI）和CDE为硬段,固定摩尔比为1∶3∶2,采用两步法制备了自修复聚氨酯脲（SH-PUU）弹性体,并对SH-PUU进行了红外光谱测试、拉曼光谱测试、力学性能测试、自修复性能测试、划痕修复微观形貌观察、应力松弛和动态力学性能测试。实验结果表明：SH-PUU的软段和硬段的玻璃化转变温度分别为-38.5℃和77.6℃,微相分离程度较高,SH-PUU具有良好的力学性能,拉伸强度为13.6MPa,断裂伸长率达531.3%;同时SH-PUU具有高效的自修复能力,试样在经过80℃修复2h后,基于拉伸强度的自修复效率达到97.1%,SH-PUU的力学性能和自修复性能达到较好的平衡。SH-PUU的高自修复能力是由动态双硫键和氢键协效增强引起的,其通过加热方式的自修复机理为：SH-PUU中的动态双硫键在80℃发生可逆交换反应,SH-PUU中的氢键在低于100℃时会重新形成。     

双动态键自修复聚氨酯研究进展

聚氨酯(PUR)因其优异的综合性能被广泛应用于各个领域,为延长PUR的使用寿命,可修复PUR成为研究热点。简述了可修复PUR的发展历程,介绍了基于二硫键、氢键、D-A键、硼酸酯键、π-π堆积作用的PUR的自修复机理,并列举出了含这5种动态键的可自修复PUR材料的合成方式及性能标准。指出了含有单一动态键的PUR存在着修复性能与力学性能间的矛盾,及通过多种动态键协同以求实现矛盾平衡的应用。相比单一动态键型PUR,这类PUR材料内多种动态键存在相互协同作用,可进一步提高材料的综合性能。对未来的研究方向如降低修复温度、降低成本等方面提出展望。     

高性能自修复水性聚氨酯制备及性能

首先将自制的5-(2-羟乙基)-6-甲基-2-氨基脲嘧啶(UPy)作为扩链剂与聚四氢呋喃(PTMG)、异佛尔酮二异氰酸酯(IPDI)进行预聚,然后将预聚物与亲水性扩链剂2,2-二羟甲基丙酸(DMPA)反应进行扩链,利用"丙酮法"制备了一种高性能自修复水性聚氨酯材料.通过傅里叶变换红外光谱、核磁共振氢谱对制备的材料进行结...     

基于超分子相互作用的自愈合聚氨酯材料

聚氨酯材料由于其固有的氢键结构被认为是一种理想的自愈合材料。将超分子化学体系引入到聚氨酯中,可以获得性能更加出色的自愈合材料。这些基于超分子相互作用的自愈合聚氨酯材料在受损后能够恢复其大部分物理和化学性质,具有优异的性能。该文首先从不同类型的愈合机理出发,综述了近年来基于超分子相互作用的自愈合聚氨酯材料,包括氢键结合体系、基于芳香基的π-π堆积体系、链段侧链中含有离子基团并彼此形成交联点的离子交联聚合物体系、金属离子与配体进行配位引起材料交联的金属配体相互作用体系、大环分子与特定大小的分子形成包合物的主客互动体系。然后展望了自愈合聚氨酯未来发展优势。     

本征型自愈合聚氨酯及其相关复合材料的研究进展

综述了近年来本征型自愈合聚氨酯材料的研究进展,包括共价和非共价化学自愈合聚氨酯,以及负载有纳米填充物的相关复合材料的应用.归纳了这些先进材料的发展进程以及赋予其自愈合特性的不同方法,介绍了自愈合聚氨酯领域的潜在应用、挑战和未来的发展前景.     

基于动态共价键的可自愈合聚合物凝胶

简要介绍了动态共价键既具有普通共价键的高强度和稳定性,又能像分子间作用力（如氢键）那样可逆地断裂和重组的特点,以及基于动态共价键构筑智能凝胶材料的优势。综述了多种动态共价键,如芳香基苯并呋喃酮二聚体（diarylbibenzo furanone,DABBF）、三硫酯（trithiocarbonate,TTC）、芳基硼酸酯、酰腙键（acylhydrazone bond）、双硫键（disulfide bond）等的结构及其动态化学,以及应用它们合成聚合物凝胶的方法、凝胶的自愈合机理和性能。提出了发现和采用多种动态共价键构筑可自愈合聚合物凝胶的趋势,为此须解决多种动态共价键的相容性、凝胶自愈合机理与性能的光谱表征等问题,并加强应用研究。     

Effect of chain extender on microphase structure and performance of self-healing polyurethane and poly(urethane-urea)

In this work, four aliphatic chain extenders, hexanediol (HDO), hexane diamine (HDA), cystamine (CY), and cystine dimethyl ester (CDE), were chosen to synthesize four kinds of polyurethane and poly(urethane-urea)s (PUs), respectively. HDO extended polyurethanes, HDA extended poly(urethane-urea), CY extended poly(urethane-urea), and CDE extended poly(urethane-urea) were denoted as OPU, APU, CPU, and SPU, respectively. The effect of chain extender type on microphase structure and performance of four PUs was investigated. Our research showed that mechanical strength increased in the following order: OPU < SPU < CPU < APU, and self-healing performance increased in the opposite direction. This result is attributed to the increasing degree of microphase separation: OPU < SPU < CPU < APU. The optimal sample SPU has not only excellent mechanical properties (tensile strength of 27.1 MPa and elongation at break of 397.7%), but also exhibits superior self-healing performance (self-healing efficiencies of 95.3% and 93.5% based on tensile strength and elongation at break). The moderate degree of microphase separation between the soft segments and the hard segments, the introduction of disulfide bonds and low degree of hydrogen bonding are responsible for preparing a polyurethane or poly(urethane-urea) system with high mechanical strength and excellent self-healing performance simultaneously. This work provides useful information for us to develop self-healing polyurethane or poly(urethane-urea) materials in the future.     

聚N异丙基丙烯酰胺/黏土纳米复合自修复水凝胶的制备及性能

以N异丙基丙烯酰胺(PNIPA)为单体,纳米黏土硅酸镁锂(LXG)为交联剂,通过原位聚合反应制备了一种具有自修复功能的高分子/纳米黏土复合水凝胶。探讨了单体和黏土配比、单体与分散剂配比等参数对水凝胶成胶性能的影响。重点对该复合水凝胶自修复机理及性能进行评价。结果表明,当单体与黏土比例为1.5~2：1,单体与分散剂比例为1：10时水凝胶成胶性能良好;水凝胶的溶胀性能随黏土含量的增加而下降,最大溶胀率为12.8 g/g;合成的水凝胶在室温下无需任何修复剂,24 h即可实现损伤断面的良好修复,自修复效率最高为43.1 %。     

自修复涂料的研制

本文研制的自修复涂料系统含有许多特点,硅氧烷单体自修复剂HOPDMA-PDES按相分离分散在介质中,而同时催化剂在微胶束中,HOPDMA与PDES不会发生反应,只有当催化剂从微胶束中破壳而出与自修复剂完全混合并固化后,自修复剂才完成任务。     

Hidden Relationships between N-Glycosylation and Disulfide Bonds in Individual Proteins

N-Glycosylation (NG) and disulfide bonds (DBs) are two prevalent co/post-translational modifications (PTMs) that are often conserved and coexist in membrane and secreted proteins involved in a large number of diseases. Both in the past and in recent times, the enzymes and chaperones regulating these PTMs have been constantly discovered to directly interact with each other or colocalize in the ER. However, beyond a few model proteins, how such cooperation affects N-glycan modification and disulfide bonding at selective sites in individual proteins is largely unknown. Here, we reviewed the literature to discover the current status in understanding the relationships between NG and DBs in individual proteins. Our results showed that more than 2700 human proteins carry both PTMs, and fewer than 2% of them have been investigated in the associations between NG and DBs. We summarized both these proteins with the reported relationships in the two PTMs and the tools used to discover the relationships. We hope that, by exposing this largely understudied field, more investigations can be encouraged to unveil the hidden relationships of NG and DBs in the majority of membranes and secreted proteins for pathophysiological understanding and biotherapeutic development.     

Self-healing polyurethane based on a substance supplement and dynamic chemistry: Repair mechanisms and applications

This review systematically summarizes the repair mechanisms and applications of self-healing polyurethane (SHPU) materials aiming at energy conservation and safety under different repair methods. As of now, the repair methods that have emerged can be divided into two categories: substance landfill and bond repair. In terms of the repair mechanisms for both, the former involves the release of healing agents from micro-carriers (microcapsules, hollow fibers, and microvascular) to fill the damaged area upon external impact. In contrast, bond repair combines physical and chemical changes triggered by light, heat, and other factors. To achieve efficient self-healing in this mode, both the reorganization of broken chemical bonds and the high mobility of chain segments are crucial. Reversible covalent bonds and supramolecular interactions, as two branches of aforementioned reversible chemical bonds, share the responsibility for maintaining efficient self-healing despite infinite cycling. Additionally, multiple synergistic crosslinked networks, special nanomaterials, and microphase separation are often used to solve the problem of incompatible healing efficiency and mechanical strength in bond repair. When the perspective is focused on the application, this gradually improved SHPU with strong potential and comprehensive performance has provided raw materials for many fields related to human development, such as road, architecture, healthcare, and electronic.