测氧法研究受阻酚抗氧剂的抗氧化活性及反应动力学

采用测氧法考察了4种市售受阻酚抗氧剂的抗氧化活性,同时对其清除ROO·反应进行了动力学分析。结果表明:4种受阻酚抗氧剂对ROO·均具有良好的清除作用,并且抗氧化活性随着酚羟基浓度增加而增大。在同等的酚羟基浓度下,抗氧剂的抑制速率常数kinh值从大到小的顺序为抗氧剂1098、抗氧剂BHT、抗氧剂1010、抗氧剂1076。抗氧剂的抗氧化活性与功能基团的个数和对位取代基的供电性密切相关,酚胺复合型抗氧剂体现出更高的抗氧化活性。     

浅谈受阻酚抗氧剂ky-586工业化生产的技术要点

本文从提高收率和产品质量出发,阐述了ky - 583工业化生产的技术要点。     

非对称型受阻酚抗氧剂KY—586的合成

以邻甲酚、异丁烯、丙烯酸甲酯、二缩三乙二醇为原料,通过烷基化反应、加成反应、酯交换反应合成非对称型受阻酚抗氧剂KY－586,研究了合成的工艺条件及产品的表征。     

受阻酚类润滑油抗氧剂的性能研究

用旋转氧弹法和加压差示扫描量热法考察了受阻酚类抗氧剂在基础油中的抗氧化性能。结果表明,大分子量的单酚抗氧剂和双酚结构的抗氧剂具有优异的抗氧化性能;计算所得抗氧剂在基础油中的氧化活化能数据对抗氧剂的应用有借鉴作用。     

非对称型受阻酚抗氧剂ky-586结晶的研究

主要介绍非对称型受阻酚抗氧剂ky-586在结晶过程中的影响因素.     

非对称型受阻酚类抗氧剂的研究新进展

非对称型受阻酚类抗氧剂以其特殊的结构显著提高了聚合物的抗氧化效率,新型非对称型受阻酚的探索与开发代表了当今世界聚合物抗氧化领域的一大发展趋势。简述了非对称型受阻酚类抗氧剂的结构特性及抗氧化机理,重点介绍了几种典型的半受阻酚类抗氧剂的合成及应用,指出了非对称型受阻酚类抗氧剂的研究方向。     

高相对分子质量受阻酚抗氧剂KY-1330的合成与应用

介绍了高相对分子质量受阻酚抗氧剂KY-1330的特点、合成及应用。着重介绍了该抗氧剂在国内的研发、生产及应用情况。对现有的合成工艺路线进行了比较,认为2,6-二叔丁基苯酚加入多聚甲醛,再与均三甲苯缩合的二步法更适合于国内。     

受阻酚抗氧剂对NBR/WCB共混胶耐热老化性能的影响

研究了抗氧剂2-叔丁基-6-(3-特丁基-2-羟基-5-甲基苯基)-4-甲基苯酚丙烯酸酯(简称GM)、抗氧剂264和抗氧剂2246对NBR/WCB共混胶的硫化特性、力学性能和耐热老化性能的影响,并通过TG分析表征NBR/WCB共混胶的耐热稳定性。结果表明,与抗氧剂264和抗氧剂2246相比,抗氧剂GM对NBR/WCB共混胶具有防止焦烧、加快硫化速度和软化胶料的作用。添加抗氧剂GM的共混胶比加入抗氧剂264和2246的共混胶具有更优异的耐热老化性能。TG分析表明,在3种抗氧剂中,加入抗氧剂GM的NBR/WCB共混胶的耐热稳定性最高。     

国产抗氧剂在聚乙烯农膜中的应用

目前我国农业塑料薄膜的生产量,地膜和棚膜的覆盖面积已居世界首位,并持续高速发展。农用塑料薄膜以其生产使用的树脂原料不同一般可分为聚氯乙烯农膜和聚乙烯农膜两类。农业的发展以及人们环保意识和观念的提高,对聚乙烯农膜提出了更高的要求,同时促进了聚乙烯农膜所用助剂,特别是国产抗氧剂的科研、生产和应用研究。本文着重探讨和论述了国产抗氧剂在聚乙烯农膜中的应用。     

MgAlON复合材料的抗氧化性分析

实验原料为电熔镁铝尖晶石、高纯电熔镁砂、登封轻烧铝矾土、Al-Al2O3-MgO混合细粉;少量助烧剂.将原料混练均匀,压制成型放入高温氮化炉烧成,将烧成后试样分为粉料和块状进行抗氧化性实验.测定了试样的氧化增重率、TG-DTA曲线、氧化后试样的表观特征、氧化前后试样的物理性能.试验结果表明:相同工艺条件下制备的MgAlON结合尖晶石复合材料的抗氧化性优于MgAlON结合MgO复合材料的抗氧化性;同种骨料的试样,矾土基MgAlON复合材料试样的抗氧化性优于氧化铝基MgAlON复合材料试样的抗氧化性;MgAlON结合尖晶石复合材料经等温氧化后,其常温力学性能无明显降低.     

Grafting of poly(acrylic acid) onto poly(amidoamine)-functionalized graphene oxide via surface-mediated reversible addition-fragmentation chain transfer polymerization

Graphene oxide was modified with third-generation poly(amidoamine) (PAMAM) to obtain dendrimer-grafted GO (DGO) with high content of functional groups. DGO's amine groups were conjugated with S-(thiobenzoyl)thioglycolic acid as proved by XPS and poly(acrylic acid) was grafted onto surface via RAFT polymerization (DGO@PAA). FT-IR results approved the synthesis of samples whereas TGA revealed 40.3% grafting of PAA. XRD patterns showed that with further modification, d-spacing increased. According to Raman spectra, modification resulted in more disordered structure whereas DGO@PAA showed a high value of I_D/I_G. Morphological studies were performed by SEM and TEM that showed a polymeric layer covered the surface of nanosheets.     

八角茴香中莽草酸提取工艺及抗氧化性研究

通过回流提取法、超声提取法、微波提取法对八角茴香中莽草酸的提取工艺进行优化。经过单因素与正交试验获得最佳提取工艺为微波提取方法下提取时间4 min、微波功率400 W、料液比1：20（g/mL）,莽草酸得率4.92％。用DPPH自由基捕获分光光度法对提取液莽草酸进行了研究,发现其对自由基清除率可达到12.71％,具有一定的抗氧化性。     

Synthesis and characterization of poly(methyl methacrylate) star polymers

Star-branched poly(methyl methacrylate)s (PMMA) were synthesized by linking ‘living’ arms (produced by anionic polymerzation) with ethylene glycol dimethacrylate. Stars having arm molecular weights of 10000 and 40000 and between 4.9 and 18.7 branches were produced. The polymers were characterized using light scattering, size exclusion chromatography, and viscometry. It was found that well-defined PMMA stars were obtained only at the higher (40000) arm molecular weight. The stars prepared using the lower molecular weight (c. 10000) arms contained very high molecular weight gel components.     

Synthesis and antioxidant activities in polyolefin of dendritic antioxidants with hindered phenolic groups and tertiary amine

Two novel primary antioxidants with dendritic structure and hindered phenolic groups were synthesized using 3‐(3,5‐diter‐butyl‐4‐hydroxyphenyl) propionic acid as raw material and dendritic poly(amidoamine) (PAMAM) as linker in chloroform. The antioxidant activities of the dendritic antioxidants were evaluated in polyolefin by melt flow index (MFI), yellowness index (Y.I.), and oxidation induction time (OIT). The dendritic antioxidants had excellent processing property and oxidation resistance behavior in polyolefin. At the same weighed amount of antioxidant, the MFI and Y.I. values of mulitiple‐extruded polyethylene (PE) stabilized with the dendritic antioxidants were smaller than those of the commercial antioxidants, as well as the OIT values of polyethylene (PE) stabilized with the dendritic antioxidants were larger. Applying to polypropylene, the antioxidant ability of the second‐generation dendritic antioxidant (G2.0 dendritic antioxidant) with larger molecular weight was superior to the commercial antioxidants and that of the first‐generation dendritic antioxidant (G1.0 dendritic antioxidant) was equal to the commercial antioxidants. The dendritic antioxidants can prevent polyolefin from breaking of macromolecular chain in processing and had stabilizing effect in polyolefin in service life by donating H‐atoms and electron to free radicals. The dendritic antioxidants combined with Irgafos 168 had improvement of antioxidant activities of the dendritic antioxidants in polyolefin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Glass-Reduced SiAlONs with Improved Creep and Oxidation Resistance

Ceramics containing α-SiAlON with improved high-temperature properties such as thermal stability and creep and oxidation resistance were synthesized. The influence of starting composition on the amount of residual grain-boundary phase has been explored. Results have been interpreted in terms of compatibility phase relationships in the Si₃N₄–AlN–Al₂O₃–Re₂O₃ system and transient evolutions.     

Upgrading the adhesion properties of a fast‐curing epoxy using hydrophilic/hydrophobic hyperbranched poly(amidoamine)s

A homologous series of hyperbranched polymers (HBPs) was prepared following a well‐defined method and their formation in a polymeric form bearing different extents of branching with amine functional groups at the terminals was verified using different techniques such as Fourier Transform Infrared, ¹H Nuclear Magnetic Resonance, Differential Scanning Calorimetry, and Gel Permeation Chromatography. Toughening of a commercially available fast cure epoxy was aimed through reactive blending with the formed HBPs that exhibit variation in polarity and branching according to the relevant synthesis strategy employed for each polymer. The mechanical properties (impact resistance, pull‐off adhesion, and bending) of the resulting coating films pertaining to each epoxy formulation after adhering to metal substrates revealed obvious progress in their performance with respect to a control sample that was hardened exclusively in absence of any HBP. The results were explained on the light of the ability of this class of materials to impose flexibility and dilute the intensive crosslink density associated frequently with the rapid curing of epoxy systems. The extent of gained enhancement for each formulation was accounted for by the molecular architecture of the HBPs, their degrees of branching, polarity, and relative reactive contents of primary amino groups in each case. In addition, the influence of these parameters on a proper wetting over the substrate and morphology of the films in each case was also studied using scanning electron microscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

酯端基型聚酰胺胺树形高分子对聚(3-羟基丁酸戊酸共聚酯)结晶性能的影响

采用不同比例G3.5酯端基类型的聚酰胺胺(PAMAM)树形高分子氯仿溶液与聚(3-羟基丁酸酯-co-3-羟基戊酸酯)(PHBV)树脂氯仿溶液进行共混并流延成膜,采用差示扫描量热分析、偏光显微镜以及拉伸和直角撕裂等方式对制备的PHBV/PAMAM复合膜进行表征。结果表明,随着PAMAM树形高分子的加入,PHBV/PAMAM复合膜的玻璃化转变温度（Tg）越来越明显,初步表明其韧性增强; G3.5 PAMAM树形高分子的加入,可使PHBV的结晶度由61.70 %先下降至24.02 %,并逐渐下降,最后至结晶消失; PAMAM树形高分子的加入可使PHBV的直角撕裂强度大幅度提高,最高可由8.90 kN/m提高到22.10 kN/m;当PAMAM树形高分子含量为2.0份时,增韧效果最好。