PLA表面温敏性互穿网络水凝胶的UV接枝及其透湿性

为制备一种温度响应型智能调湿织物,采用丙烯酸间苯二酚二缩水甘油酯在聚乳酸(PLA)非织造布表面通过热处理引入不饱和双键,在紫外光照射下引发聚丙烯酰胺/聚(N-异丙基丙烯酰胺)(PAAM/PNIPAAM)互穿网络水凝胶体系接枝于PLA非织造布表面。分析接枝后织物的化学结构、形貌,探究PNIPAAM用量在不同温度下对织物透湿性的影响。结果表明,PLA非织造布表面不饱和双键预处理-紫外光接枝两步法可以成功实现温敏性互穿网络水凝胶与PLA非织造布的接枝,所构建的织物表面具有丰富的孔隙结构,互穿网络中PNIPAAM质量分数为4.5%、AAM质量分数为10%时,接枝织物在24℃下的透湿量为1731 g/(m²·d),在38℃下的透湿量高达3601 g/(m²·d),赋予PLA非织造布温度可控的智能透湿性能,将其应用于伤口敷料领域可在低温低透湿性时保持伤口湿润、高温高透湿性时降低创面温度。     

天然纤维素均相接枝聚N-异丙基丙烯酰胺及其温敏性研究

利用基于电子转移再生活性种的原子转移自由基聚合(AGET ATRP)将单体N-异丙基丙烯酰胺(NIPAAM)接枝到天然纤维素上制得纤维素接枝聚N-异丙基丙烯酰胺(cell-PNIPAAM)。FT-IR、1H-NMR和13C-NMR分析表明,成功合成了cell-PNIPAAM;凝胶渗透色谱分析表明,接枝率随反应体系中N,N-二甲基甲酰胺（DMF）体积比的减小而增大,该聚合物分子质量的多分散性在2.0左右,表明聚合反应在一定程度上是可控的;热重分析显示,聚合物的热稳定性相比于天然纤维素略为提高;TEM图片显示,聚合物在高于其最低临界相转变温度(约为34℃)时,聚合物与水相分离并呈球形结构,平均直径约为40 nm。     

温敏棉织物的制备及其性能分析

研究接枝棉纤维织物的制备方法及织物性能.采用溶液自由基引发接枝的方法,将N-异丙基丙烯酰胺接枝聚合到棉纤维织物上.借助FTIR对接枝样进行了结构分析,并提出了相应的引发接枝机理;用DSC微观测定了接技聚合棉织物的温敏性,发现较低临界溶解温度接近35℃;使用自制水通量装置对其温敏性进行了宏观表征,认为接枝增重率达到一定程度,30℃与40℃的水通量变化明显.     

纤维素纳米纤维接枝聚水凝胶的制备及其结构性能的研究

将聚N-异丙基丙烯酰胺(PNIPAM)接枝到纤维素纳米纤维上,通过增大凝胶比表面积、缩小体积尺寸提高温度响应速度。PNIPAM接枝的最佳反应条件为:反应温度40℃、纤维素纳米纤维膜和N-异丙基丙烯酰胺质量比m(N)∶m(C)=15.5∶1、引发剂浓度10.5 mmol/L、反应时间3 h。扫描电子显微镜表明,纤维表面经NIPAM接枝处理后,纤维间出现粘结现象且表面粗糙。红外光谱和X射线光电子能谱表明,PNIPAM成功接枝在纤维素纤维上。差热扫描表明,PNIPAM-g-Cell接枝率为30%时,水凝胶的LCST显著提高。去溶胀动力学表明,接枝率越高,PNIPAM-g-Cell水凝胶越敏感;PNIPAM-g-Cel扩散信号强度比值越大,扩散程度越大。     

氨基硅油整理法在温敏纺织品制备中的应用

温敏纺织品作为智能纺织品的重要组成部分,可响应环境温度的变化而调节自身的性能,在调温调湿、抗浸储水、生物医用等领域具有良好的应用前景。然而,如何将温敏聚合物高效温和地接枝到纺织品上是温敏纺织品制备过程中的难题。介绍了一种简单易行、普适性强的接枝方法,采用氨基硅油整理法在织物表面引入高活性的反应基团氨基,再通过原子转移自由基聚合(ATRP)技术接枝温敏高分子链。经由氨基硅油整理的棉织物柔顺性提高,水洗稳定性良好,红外和接触角等实验结果均证明温敏性单体N-异丙基丙烯酰胺(NIPAAm)被成功接枝聚合到织物表面,且接枝率高达41.2%。所得织物具有良好的温敏性能,可通过改变温度实现织物表面亲/疏水性的可逆转变。     

SAH阴离子天然高分子改性絮凝剂的合成及应用

本文研究了以玉米淀粉为基材,与丙烯腈(聚丙烯酰胺的降解回收料)进行接枝共聚,经水解制得弱阴离子型絮凝剂,并进一步羟甲基化和磺化,从而合成强阴离子型天然高分子改性絮凝剂-SAH.在探讨接枝共聚反应机理的基础上,重点阐明了引发剂浓度、原料投料比、反应温度、反应时间等对接枝率和接枝效率的影响.把SAH应用于印染废水及造纸厂污水的处理、COD去除率和浊度去除率都达到90%以上,取得了良好的絮凝效果.     

天然高分子改性聚丙烯酰胺的研究

聚丙烯酰胺能与一些天然高分子进行接枝共聚和交联 ,从而赋予它新的结构和使用性能 ,在石油工业、造纸工业、矿业、水处理等领域具有广阔的应用前景。本文综述了用淀粉、纤维素、壳聚糖这三种天然高分子改性丙烯酰胺的研究和应用情况     

H2O2-H2A引发的PNIPAAm接枝棉纤维的制备与功能性研究

以双氧水-抗坏血酸(H₂O₂-H₂A)为引发剂，水为溶剂，通过溶液自由基接枝聚合反应引发棉纤维接枝聚N-异丙基丙烯酰胺(PNIPAAm)。红外分析表明，PNIPAAm已成功接枝到棉纤维上。研究单体浓度固定时引发剂浓度对棉纤维接枝率的影响，测量不同温度下水滴在接枝棉表面的瞬时接触角，结果表明在最低临界溶液温度(LCST)左右接枝棉具有温敏亲/疏水性。在不同温度下对接枝棉进行滴水试验，即将水滴加到接枝棉上观察其完全吸收的时间，不同温度下的浸润时间差值越大，接枝棉温敏吸水性越强，当引发剂溶度为0.06 mol/L时，接枝棉的温敏吸水性最强。     

SAH阴离子天然高分子改性絮凝剂的合成及应用

本文研究了以玉米淀粉为基材，与丙烯腈(聚丙烯酰胺的降解回收料)进行接枝共聚，经水解制得弱图离子型絮凝剂，并进一步羟甲基化和磺化，从而合成强阴离子型天然高分子改性絮凝剂-SAH．在探讨接枝共聚反应机理的基础上，重点阐明了引发剂浓度、原料投料比、反应温度、反应时间等对接枝率和接枝效率的影响，把SAH应用于印染废水及造纸厂污水的处理、COD去除率和浊度去除率都达到90％以上，取得了良好的絮凝效果。     

涤纶纺织品的低温等离子体温敏改性

为制备具有温敏效应的智能型涤纶纺织品,运用低温等离子体引发涤纶织物接枝聚合N-异丙基丙烯酰胺(NIPAAm)凝胶.通过对织物的水通时间、纤维化学结构以及干湿状态织物表面形态的测试,表征了改性前后织物结构及性能的变化,并探讨了改性后织物增重率和"开关效应"的关系.结果表明:NIPAAm已被引入涤纶织物表面;经接枝聚合后的...     

等离子体处理亚麻接枝混合单体的研究

采用介质阻挡放电低温等离子体对亚麻织物进行处理,引发接枝改性,采用混合丙烯酸和苯乙烯为接枝单体来减少均聚产物,以提高接枝率,改善亚麻织物的染色性能。确定了最佳工艺条件:等离子体处理时间为4 min,处理频率为3 kHz,处理电压为13 kV,接枝温度为60℃。采用红外光谱和X射线衍射对接枝共聚物进行表征,同时对反应机制进行了探讨。结果表明,亚麻大分子上接枝了丙烯酸和苯乙烯的混合单体,接枝亚麻对阳离子染料的上染率有所提高。     

一种高分子阳离子活性染料的合成及应用性能研究

以聚乙烯亚胺(PEI)为高分子骨架,2-(1-蒽醌基氨基)-4,6-二氯-1,3,5-三嗪为染料母体,通过化学接枝,合成了高分子染料,再对聚乙烯亚胺高分子上的氮进行季铵化,得到高分子阳离子活性染料.通过红外光谱表征合成的高分子阳离子活性染料的结构,并在无盐染色工艺条件下对棉织物、羊毛进行浸染,结果显示具有较高的上染百分率和固色率,摩擦牢度较好.     

A Comparative Study of Natural Antimicrobial Delivery Systems for Microbial Safety and Quality of Fresh‐Cut Lettuce

Nanoencapsulation can provide a means to effectively deliver antimicrobial compounds and enhance the safety of fresh produce. However, to date there are no studies which directly compares how different nanoencapsulation systems affect fresh produce safety and quality. This study compared the effects on quality and safety of fresh‐cut lettuce treated with free and nanoencapsulated natural antimicrobial, cinnamon bark extract (CBE). A challenge study compared antimicrobial efficacy of 3 different nanoencapsulated CBE systems. The most effective antimicrobial treatment against Listeria monocytogenes was chitosan‐co‐poly‐N‐isopropylacrylamide (chitosan‐PNIPAAM) encapsulated CBE, with a reduction on bacterial load up to 2 log₁₀ CFU/g (P < 0.05) compared to the other encapsulation systems when fresh‐cut lettuce was stored at 5 °C and 10 °C for 15 d. Subsequently, chitosan‐PNIPAAM‐CBE nanoparticles (20, 40, and 80 mg/mL) were compared to a control and free CBE (400, 800, and 1600 μg/mL) for its effects on fresh‐cut lettuce quality over 15 d at 5 °C. By the 10th day, the most effective antimicrobial concentration was 80 mg/mL for chitosan‐PNIPAAM‐CBE, up to 2 log₁₀ CFU/g reduction (P < 0.05), compared with the other treatments. There was no significant difference between control and treated samples up to day 10 for the quality attributes evaluated. Chitosan‐PNIPAAM‐CBE nanoparticles effectively inhibited spoilage microorganisms’ growth and extended fresh‐cut lettuce shelf‐life. Overall, nanoencapsulation provided a method to effectively deliver essential oil and enhanced produce safety, while creating little to no detrimental quality changes on the fresh‐cut lettuce.     

互穿聚合物网络温敏凝胶对棉织物液态水分传递的影响

为使高分子凝胶在纺织品改性中得到更好的应用,采用互穿聚合物网络（IPN）方法,制备了一种IPN 壳聚糖/聚Ｎ?异丙基丙烯酰胺温敏凝胶;并以戊二醛为交联剂,IPN 凝胶为改性剂,采用二浸二轧法获得改性棉织物,以提高棉织物的液态水分传递能力。研究了不同质量增加率对改性棉织物的透湿性以及液态水分传递能力的影响。结果表明：IPN 凝胶牢固附着在棉纤维表面,且改性棉织物的低临界溶解温度为34.45℃;温度高于低临界溶解温度时,高质量增加率的改性棉织物透湿性显著提高;改性棉织物对液态水分具有较强的单向传递能力,高质量增加率的改性棉织物液态水分传递能力较好;IPN凝胶可显著改善棉织物的透湿和液态水分传递能力。     

Enhancement reactivity of Bombyx mori silk fibroins via genipin-mediated grafting of a tyrosine-rich polypeptide

Bombyx mori silk fibroin has potential applications in the biomedical field owing to its satisfactory biocompatibility. In the present work, a tyrosine-rich polypeptide (P) with the sequence of GKGYGGYGK was grafted onto fibroin molecules using a natural cross-linking agent of genipin (GP), aiming at improving the reactivity of the fibroin-based materials. Incubation of the polypeptide-grafted fibroin membrane was subsequently carried out, with a mushroom tyrosinase (MT) and a model functional macromolecule of ε-poly-l-lysine (ε-PL). The changes in the structure and composition of the silk fibroin before and after polypeptide grafting were examined by means of size exclusion chromatography and amino acid analysis. The results indicated that the polypeptide was covalently bonded to fibroin chains and evidently promoted the succeeding enzymatic coupling of ε-PL with fibroins, resulting in a higher content of ε-PL compared to the control. The obtained antibacterial activities against S. aureus and E. coli for the fibroin membrane treated with GP/P and MT/ε-PL was more satisfactory than others. Cytotoxicity testing reveals that polypeptide grafting did less impact on the biocompatibility of silk fibroins. The present work provides a novel method to improve the reactivity of silk fibroins and it can be utilized for bio-functionalization of silk fibroin.     

高能辐射接枝在纺织品改性方面的研究进展

高能辐射接枝技术因高效率、节能环保等优异的性能受到科学研究者越来越多的关注,并已被广泛用于各种材料的改性加工。介绍了高能辐射的种类、高能辐射接枝技术的作用原理和在纺织品应用中的加工方法,并对纺织品接枝改性中常用的几种高能辐射接枝处理及其研究进展进行了详细介绍。认为高能辐射接枝具有可在室温(或低温)下进行、接枝条件还可以随辐射源和聚合系统的条件而广泛地变化、高能辐射处理相对均匀、处理效率高、污染少等优点。     

制酒行业中的高分子

天然高分子、合成高分子以及改性高分子广泛应用于制酒行业，高分子材料在制酒原料、饮料酒组分及产品后处理等方面对制酒过程和产品质量都有影响。制酒行业中应用的天然高分子有淀粉、纤维素、半纤维素及蛋白质等；合成与改性高分子材料应用于酒类产品的包装及贮存、产品的分析及纯化、生产污水的处理等。     

Water–water and water–macromolecule interactions in food dehydration and the effects of the pore structures of food on the energetics of the interactions

A molecular dynamics (MD) modeling and simulations approach has been rationally built and developed to study porous food systems constructed with amylose and dextran chains. The findings from our MD studies indicate that the presence of food macromolecules decreases the energetics of the water–water interactions for the nearby water molecules in the pore space, but provides additional water–macromolecule interactions that can significantly outweigh the partial loss of water–water interactions to make the adjacent water molecules strongly bound to the food macromolecules so that the water activity and water removal rate are decreased as dehydration proceeds and, thus, the dehydration energy requirement would be increased. The effects of pore structures are greater in systems with higher densities of food macromolecules, smaller in size pores, and stronger water–macromolecule interactions. Dehydration of food materials can thus be reasonably expected to start from the largest pores and from the middle of the pores, and to have non-uniform water removal rates and non-planar water–vapor interfaces inside individual pores as well as across sections of the food materials. The food porous structures are found to have good pore connectivity for water molecules. As dehydration proceeds, water content and the support from water–water and water–macromolecule interactions both decrease, causing the food porous structures to adopt more compact conformations and their main body to decrease in size. Dehydration in general also reduces pore sizes and the number of pore openings, increases the water–macromolecule interactions, and leads to the reduction of the overall thermal conductivity of the system, so that more energy (heat), longer times, and/or greater temperature gradients are needed in order to further dehydrate the porous materials. Our thermodynamic analysis also shows that the average minimum entropy requirement for food dehydration is greater when the water–macromolecule interactions are stronger and the food macromolecular density is higher. The importance of the physicochemical affinity of food molecules for water and of the compatibility of the resultant porous structures with water configurational structures in determining food properties and food processing through the water–macromolecule interactions, is clearly and fundamentally verified by the results and discussion presented in this work.     

相变调温纺织品制备方法的研究进展

为明晰制备工艺对调温纺织品性能的影响,综述了相变调温纺织品的2种制备方法:即在中空纤维中填充相变材料或将相变材料加入纺丝液制备相变纤维,再经织造形成相变织物;或者通过直接填充、表面整理、表面接枝改性等直接复合方式获得相变织物。分析认为:中空纤维填充法对选用的纤维材料要求较高;直接填充法工艺简单、操作方便,但会使纺织品舒适性变差;微胶囊纺丝和微胶囊表面整理的方法已实现工业化,但所得纺织品的焓值较低;静电纺丝法不易实现大规模工业化;表面接枝法能够实现相变材料与纺织品的耐久性结合,但工艺复杂繁琐;最后对相变材料的调温纺织品未来的发展方向进行了展望。