RAFT聚合制备两亲性嵌段共聚物及其应用研究

研究用两亲性嵌段共聚物和纳米二氧化硅制备超疏水表面.采用可逆加成-断裂链转移聚合法(RAFT)合成了两亲性嵌段共聚物聚甲基丙烯酸叔丁酯-b-聚(4-乙烯基吡啶),用红外光谱,核磁共振,凝胶渗透色谱对聚合物进行了表征,将嵌段共聚物接枝到纳米二氧化硅上,形成一个有机无机杂化材料,通过调节pH值来控制杂化材料在水中的聚集行为,构筑了微纳双重结构的粗糙表面.该表面为超疏水表面,对水接触角达151°,滚动角5°.扫描电镜分析表面形貌表明:具有微纳双重结构的类似荷叶表面是形成超疏水的根本原因.     

高强度PAM/PVA互穿网络水凝胶的合成

以聚丙烯酰胺(PAM)为基体,聚乙烯醇(PVA)为增强体,采用两步水溶液聚合法合成具有较高机械强度的PAM/PVA互穿网络水凝胶.研究PVA、交联剂用量对PAM/PVA互穿网络水凝胶拉伸强度及伸长率的影响,探讨水凝胶的应力松弛及析出PVA对水凝胶的增韧机理.实验表明,制备的互穿网络水凝胶具有较高的机械强度和韧性,最高拉伸强度为2.4 MPa,伸长率为3 000%.最后,采用傅里叶红外光谱(FTIR)、扫描电子显微镜(SEM)及X-射线衍射(XRD),对PAM/PVA互穿网络水凝胶的结构与形貌进行表征.     

杂臂星型苯乙烯-丁二烯共聚物的结构与性能

采用自制的含碳锡键和聚二烯烃臂的多官能团大分子有机锂作为引发剂,四氢呋喃为结构调节剂,环己烷为溶剂,阴离子聚合法合成了杂臂星型苯乙烯-丁二烯共聚物;依据多官能团大分子引发剂中二烯烃的不同,所合成的共聚物分别为PI-Sn-(SBR)3和PB-Sn-(SBR)3。用GPC1、H-NMR和DSC分析了杂臂星型共聚物的结构,并研究了硫化胶的物理机械性能和动态力学性能。结果表明,杂臂星型共聚物中聚二烯烃臂中1,4结构质量分数约为90%;苯乙烯-丁二烯共聚臂中1,2-PB质量分数约为45%。DMTA测试表明杂臂星型共聚物在保持低滚动阻力的同时具有更好的抗湿滑性和低温性。两种共聚物都满足高性能轮胎胎面胶的要求。     

水性丙烯酸酯共聚物药物包衣材料合成的研究

该文介绍了将教师的科研成果转化为学生实验项目的教学实践方法,将教师从事科研工作取得的科研成果转化成了开放性实验——药物包衣用丙烯酸酯共聚物薄膜材料的乳液聚合反应及其包衣技术。使学生了解到了一种新型的涂料,同时也是一种新型的功能高分子材料。由于该实验来源于教师的科研和生活实践,提高了学生的实验兴趣,收到了良好的实验效果。     

Investigation on Mechanical Properties of CMSLDS/Acrylate Copolymeric Blending Films for Warp Sizing

Carboxymethyl starch with lower degree of substitution was blended with acrylate copolymer for revealing the relation between mechanical properties and chemical structure of blending film.Effects of carboxymethylation of starch,acrylate constituent units of acrylate copolymers,and copolymer content of the film on the properties were investigated.The mechanical properties were evaluated in terms of tensile strength,breaking elongation,abrasion resistance,and flex-fatigue resistance.Film morphology was examined with X-ray diffraction (XRD),scanning electron microscopy (SEM),and atomic force microscope (AFM).It was found that the properties depended on the degree of substitution of carboxymethyl starch,chemical structure of acrylate units,and content of acrylate copolymer.Phase-separation of the two ingredients occurred within film matrix and the separation was decreased after starch carboxymethylation.Breaking elongation and flex-fatigue resistance of the film reached maximums when acrylate copolymer content was 50%.Excessively increasing the content of acrylate copolymer reduced the film properties.     

PEG/AA/AM水凝胶的制备及性能研究

以聚乙二醇(PEG)、丙烯酸(AA)、丙烯酰胺(AM)为原料,N,N′-亚甲基双丙烯酰胺(MBA)为交联剂,采用辉光放电等离子体引发聚合技术在水溶液中一步制得了聚乙二醇/丙烯酸/丙烯酰胺(PEG/AA/AM)水凝胶.考察了放电电压、放电时间、交联剂用量、聚乙二醇含量对凝胶吸水倍率的影响,并用红外光谱(FT-IR)表征了凝胶的结构,用紫外可见分光光度计(UV)研究了水凝胶对结晶紫的脱色行为.结果表明,在最佳的合成条件下,所得水凝胶的最大吸水倍率达到240 g.g-1,PEG/AA/AM水凝胶具有pH敏感性,180 min时对浓度为200 mg.L-1的结晶紫的脱色率可达到94%.     

Novel enzymatically crosslinked chitosan hydrogels with free-radical-scavenging property and promoted cellular behaviors under hyperglycemia

The impairment of regenerative processes induced by high blood-glucose level (hyperglycemia) and excessive reactive oxygen species (ROS) contributes to the diabetic complication progression and development. In this study, an injectable, in situ crosslinkable chitosan hydrogel with ROS-scavenging capability was developed by conjugating gallic acid onto the chitosan backbone (CGA). We hypothesized that gallic acid serves as both antioxidant and crosslinking moieties to form hydrogel in situ by means of enzymatic crosslinking with horseradish peroxidase (HRP). The rapid gelation (from 30 s) was observed by vial tilting. The mechanical properties and microstructures of CGA hydrogels can be well controlled by varying the concentrations of H₂O₂. The ROS-scavenging ability of these CGA hydrogels was demonstrated against DPPH radical, hydroxyl radical, and total reducing power. Notably, in an in vitro hyperglycemia environment, CGA hydrogels significantly improved the proliferation and migration of human dermal fibroblast cells, which are closely related to diabetic wound healing. These results suggest that CGA hydrogels have potential as advanced materials for the treatment of diabetes-related diseases via attenuating the excessive ROS production and improving cellular behaviors.     

高强度物理-化学混杂双网络水凝胶的制备及性质

以聚乙烯醇（polyvinyl alcohol, PVA）和丙烯酰胺（acrylamide, AM）为原料, 采用“一锅煮”及紫外辐照结合冷冻 解冻两步聚合法制备聚乙烯醇/聚丙烯酰胺(PVA/PAM)混杂双网络水凝胶, 并对水凝胶的力学性能、 溶胀性能、 失水性能以及自愈合性进行测试和分析. 结果表明, PVA/PAM混杂双网络水凝胶具有较高的力学强度, 其拉伸强度为428 kPa, 失水速率和单网络水凝胶相比较慢, 具有一定的自愈合性.     

Preparation of Chitosan-g-PAMPS in H2O/scCO2 Inverse Emulsion

Chitosan(CS)was successfully modified in supercritical carbon dioxide(scCO2)by grafting method to enhance its water solubility.In this work,a three-arm star-like fluorinated polymer was synthesized by atom transfer radical polymerization(ATRP)method and applied as a surfactant in supercritical carbon dioxide(scCO2).Then 2-acrylamido-2-methyl propane sulfonic acid(AMPS)was grafted onto CS(CS-g-PAMPS)in H2O/scCO2inverse emulsion.The effects of mass ratio of water and surfactants(R w/s)and pressure of scCO2on the grafting reaction were investigated.The grafting rate,particle size,and dispersity in water of CS-g-PAMPS varied greatly as R w/s and pressure of scCO2changed.It could be found that the value of R w/s at 12 and the pressure of scCO2at 30 MPa were the optimum conditions for the grafting reaction.CS-g-PAMPS prepared in this reaction system has higher grafting rate,smaller particle sizes,and better dispersity in water than those prepared via conventional methods.     

AA／AMPS／DMDAAC三元共聚物阻垢分散剂的合成与性能研究

以丙烯酸（AA）、2-丙烯酰胺-2-甲基丙磺酸（AMPS）、二甲基二烯丙基氯化胺（DMDAAC）等为单体,亚硫酸氢钠一过硫酸铵为引发剂,采用水溶液聚合法,合成AA／AMPs／DMDAAc三元共聚物阻垢分散剂．研究结果表明,溶液中总单体质量分数为30％,引发剂质量分数为8％（占单体含量）,实验在弱碱性环境中进行,90℃下反应5h得到的共聚物有良好的阻垢分散性能．