脂肪二胺桥联受阻酚的桥联基与抗氧化性能的关系研究

以系列脂肪二胺为桥联基,3-(3,5-二叔丁基-4-羟基苯基)丙酸甲酯为原料,合成了系列脂肪二胺桥联受阻酚。采用傅里叶变换红外光谱和核磁共振氢谱对合成的系列受阻酚进行了结构表征,研究了脂肪二胺桥联受阻酚的桥联基与其在聚烯烃树脂中抗氧化性能和耐热氧化性能的关系。结果表明,脂肪二胺桥联受阻酚在2种聚烯烃材料中均具有良好的加工性能、耐热氧化性能和抗氧化性能,且随着桥联基碳数的增加,抗氧化性能、耐热氧化性能、加工稳定性和力学性能均增强;合成的抗氧剂1098的性能略优于市售抗氧剂1098的性能;脂肪二胺桥联受阻酚在线形低密度聚乙烯(PE-LLD)中的抗氧化性能优于聚丙烯(PP)。     

后过渡金属催化剂催化乙烯制备超支化聚乙烯新进展

后过渡金属催化剂的出现改写了超支化聚烯烃的合成历史,其不仅可以催化乙烯聚合成超支化聚乙烯,还可以实现对聚乙烯产品拓扑结构的控制以及相对分子质量的裁剪。本文沿着镍系以及钯系两大类后过渡金属催化剂的路线综述了近年来合成超支化聚乙烯的研究进展,重点对控制聚乙烯拓扑结构的方法及影响因素进行了详细的综述,并对超支化聚乙烯在高分子加工助剂及润滑油改进剂等领域的应用现状进行了介绍,这为进一步研究超支化聚乙烯在材料加工助剂等方面的应用提供了新的思路。     

两亲性超支化聚合物研究进展

介绍了两亲性超支化聚合物的合成方法,利用长链烷基和聚乙二醇对超支化聚合物端基接枝改性;或者对超支化聚合物改性引入活性位点,再利用其引发乙烯基单体,通过自由基聚合、开环聚合得到两亲性超支化聚合物。阐述了不同结构的两亲性超支化聚合物在溶液中的独特性质,如核壳型单分子胶束以及不同胶束形态的聚集体。详细介绍了两亲性超支化聚合物在药物输送载体、材料改性以及染料分子的封装等领域的应用现状,指出采用新的改性技术、聚合技术制备具有特殊性能的两亲性超支化聚合物以及探索其在生物医药领域的研究为今后的主要发展方向。     

超支化聚乙烯新材料的研究进展

由于具有与传统聚乙烯不同的拓扑结构,超支化聚乙烯表现出许多独特的物理性能。从聚烯烃弹性体、合成润滑油及纳米材料分散剂3个方面,对超支化聚乙烯新材料的合成及应用研究进展进行了综述,并分析了发展超支化聚乙烯新材料的优势及存在的问题。     

超支化大分子桥联水杨醛亚胺钴催化剂催化乙烯低聚

以1.0代（1.0G）超支化大分子、水杨醛和CoCl₂·6H₂O为原料,依次经过希夫碱反应和络合反应合成了3种具有不同烷基链长度的新型超支化大分子桥联水杨醛亚胺钴催化剂。对目标产物的结构进行FT-IR、UV、MS及TG表征,考察了溶剂种类、助催化剂种类、反应温度、反应压力、Al/Co摩尔比等条件对超支化大分子桥联水杨醛亚胺钴催化剂催化乙烯低聚性能的影响。结果表明,超支化大分子桥联水杨醛亚胺钴催化剂催化乙烯低聚表现出良好的催化活性和高碳烯烃（C₁₀₊）的选择性。催化活性随反应温度和Al/Co摩尔比增加先增加后下降,随反应压力增加而增加。以甲苯为溶剂,在一氯二乙基铝（DEAC）活化下,当反应温度为25℃、反应压力为0.5 MPa、Al/Co摩尔比为500时,催化活性可达1.87×10⁵ g·（mol Co）^-1·h^-1,聚合产物中高碳烯烃的含量高达42.90%。     

超支化聚乙烯的应用进展

超支化聚乙烯(HBPE)是一种可通过钯二亚胺催化剂催化乙烯链行走聚合(CWP)而大批量合成的聚合物,具有不同寻常的溶液和固态性质。近年来,HBPE作为一种新生材料,其应用前景不断被挖掘。该文总结HBPE在独特聚烯烃材料构造、药物载体、塑料加工、润滑油和纳米材料等领域的应用进展,以期对致力于HBPE应用开发的研究者们有所帮助。     

超支化型抗静电剂的合成及其在煤矿PVC阻燃输送带中的应用

合成了一种含有长链烷基的端羟基超支化聚合物,并通过两种方法（外部涂覆法和内部掺加法）将其作为PVC阻燃输送带的抗静电剂,测试了输送带的表面电阻。结果表明,在较低的质量分数下,即可使PVC阻燃输送带的表面电阻降至期望值（107数量级）,达到了理想的抗静电要求。含有超支化型抗静电剂的PVC阻燃输送带经过多次水洗和较长的存储时间,依然保持优良的抗静电性能。经计算,超支化型抗静电剂的生产成本低廉,适合大规模工业生产。     

多乙烯多胺桥联受阻酚类抗氧剂的合成及其清除DPPH·性能

以二乙烯三胺和三乙烯四胺为桥联基，β-(3,5-二叔丁基-4-羟基苯基)丙酰氯为抗氧化功能基团，通过酰胺化缩合反应合成了两类具有不同对位桥联基团的受阻酚类抗氧剂。采用傅里叶红外光谱和核磁共振氢谱证实了合成的多乙烯多胺桥联受阻酚类抗氧剂的化学结构。DPPH法研究了多乙烯多胺桥联受阻酚类抗氧剂清除自由基的性能，并探索了酚羟基个数和对位桥联基结构对受阻酚类抗氧剂清除自由基性能的影响。结果表明，多乙烯多胺桥联受阻酚类抗氧剂具有良好的清除DPPH·能力，且随着抗氧剂分子中酚羟基个数的增加，清除DPPH·的活性增加，分子中含有4个酚羟基的三乙烯四胺受阻酚类抗氧剂的抗氧化效率（AE）达到2.65×10^-2 L/(mol·s)。对位桥联基结构对受阻酚类抗氧剂清除DPPH·能力有较大影响，季戊四醇为桥联基的受阻酚类抗氧剂1010清除DPPH·能力最强，其抗氧化效率（AE）为3.08×10^-2L/(mol·s)；乙二胺为核的1.0代树枝状受阻酚类抗氧剂清除DPPH·能力最弱，其抗氧化效率（AE）为2.60×10^-2 L/(mol·s)。     

端基对超支化聚合物改性UHMWPE性能的影响

以3种不同端基的超支化聚酯(HBP)分别对超高相对分子质量聚乙烯(UHMWPE)进行共混改性,研究了HBP的端基类型和用量对UHMWPE/HBP共混物力学性能和流变性能的影响。结果表明:随着端羟基超支化聚酯HBP-OH、端苯基超支化聚酯HBP-Bz及端十六烷基超支化聚酯HBP-C16加入量的增大,UHMWPE/HBP共混物的拉伸强度不断降低,断裂伸长率呈现先增大后减小的趋势。在UHMWPE中加入HBP-C16后,共混物的复数黏度呈现上升的趋势。HBP-OH和HBP-Bz的加入量增大能增强UHMWPE大分子链的活动能力,改善了UHMWPE的加工流动性能。     

支化及超支化聚乙烯研究进展

综述了支化及超支化聚乙烯的制备方法及功能化改性研究进展,重点介绍了后过渡金属催化剂催化乙烯"链行走"制备超支化聚乙烯的研究进展,同时介绍了功能性超支化聚乙烯的应用,并展望了其发展前景。     

Polymer processing and characterization of LLDPE films loaded with α‐tocopherol,quercetin, and their cyclodextrin inclusion complexes

Natural antioxidant additives were compounded into linear low‐density polyethylene (LLDPE) using a twin‐screw counter‐rotating mixer and compression molded into films. Manufactured LLDPE films contained 2715 mg kg^?1 α‐tocopherol in its free and β‐cyclodextrin complexed form and 1950 mg kg^?1 quercetin in its free and γ‐cyclodextrin complexed form. Both cyclodextrin complexes were loaded into films at 1.5% by weight. These natural antioxidants were incorporated into LLDPE resins with two different catalyst types, Ziegler‐Natta and metallocene. Films were characterized by optical microscopy, oxidation induction time (OIT), oxygen transmission rate, contact angle analysis, and atomic force microscopy (AFM). All antioxidant additives increased the oxidative stability of LLDPE as measured by increased OIT, particularly quercetin. Natural antioxidants and their cyclodextrin inclusion complexes may provide a dual function in packaging to protect the polymer from oxidative degradation during melt processing and to delay the onset of oxidation of the packaged food during storage. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

抗氧剂对PMMA树脂的热稳定作用

采用连续本体法合成了纯聚甲基丙烯酸甲酯（PMMA）树脂,将不同种类的抗氧剂与PMMA树脂进行熔融共混,在空气气氛中采用热失重法测试了PMMA树脂的热稳定性。考察了抗氧剂种类、用量及复配比例等因素对PMMA树脂热稳定性的影响。实验结果表明,分别加入抗氧剂1076、抗氧剂2246、抗氧剂245和抗氧剂1010等主抗氧剂可以显著提高PMMA树脂的热稳定性,辅助抗氧剂（抗氧剂168）可以提高PMMA树脂的起始热分解温度,改变抗氧剂1010与抗氧剂168的复配比例时,抗氧剂1010用量越多,PMMA树脂的热稳定性越好。抗氧剂总量为2.5 ‰（质量分数,下同）,抗氧剂1010与抗氧剂168的比例为3：1时,PMMA树脂的热稳定性显著提高。     

Determination of the nature and content of antioxidant and antioxidant synergist in polyethylene and crosslinked polyethylene used in cables

It is shown that polyethylene and crossllnked polyethylene resins used for cable applications contain an antioxidant synergist in addition to an antioxidant. Their nature and content have been determined by a combination of ultraviolet and Fourier transform infrared spectroscopy and neutron activation analysis measurements. The results thus obtained suggest that part of the antioxidant compound is grafted to polymer chains during crosslinking.     

Evaluating the processability of film blowing resins

A key factor that limits the production rate in film blowing is bubble instability. Although processing conditions play an important role, it is well known that some resins are more resistant to instabilities than others. It is clear that long‐chain branching enhances stability, but it is not currently possible to model the process with sufficient accuracy to establish a quantitative relationship between rheological properties and blown film processability. It would thus be useful to be able to compare the processabilities of film resins by means of a laboratory measurement. We compared two laboratory tests that may be helpful in evaluating the ability of a resin to resist instabilities in the film blowing process. One of these was a film resin tester designed to simulate some aspects of the film blowing process, and the other was an extensional rheometer. We used a set of polyethylene resins that had been used previously in an extensive study of blown film stability. The extensional rheometer clearly shows the superiority of low‐density polyethylene but is not able to distinguish among polymers of other types. The melt tester, on the other hand, is sensitive to differences among linear polymers. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

MCS树脂的结构与性能

将甲基丙烯酸甲酯(MMA)苯乙烯(St)在氯化聚乙烯(CPE)存在下进行悬浮溶胀接枝共聚,获得MCS树脂。本文着重考察了MCS树脂的结构与性能。结果表明,连续相的透光性、橡胶相CPE的含量、两相折光指数的匹配都显著地影响MCS树脂的透明性;接枝可以改善MCS的抗冲强度,适当提高接枝率有利于MCS抗冲强度的进一步提高,但不利于其加工流动性;塑料相分子量的降低虽降低了MCS的抗冲强度,但可改善其加工流动性。     

Effect of tall oil fatty acids content on the properties of novel hyperbranched alkyd resins

Hyperbranched alkyd resins (HBRA) were synthesized by modification of hydroxylated hyperbranched polyester (HBP1‐4) with tall oil fatty acids (TOFA). The core is a hydroxylated hyperbranched polyester of fourth generation with OH groups in the periphery (18), which is endcapped with tall oil fatty acids. The occurrence of these reactions, HBP1‐4 and TOFA, was determined by making use of acid value, nuclear magnetic resonance, and hydroxyl values. The effects of TOFA and HBP1‐4 on properties of the HBRA resins were investigated by vapor pressure osmometry, differential scanning calorimetry, thermogravimetric analysis, friction resistance, and hardness. The resins with higher modification percentage (HBRA4) presented the best thermal and hydrolytic stability, but lower friction resistance and hardness. All HBRA resins presented amorphous characteristics, OH groups, and double bonds in the periphery. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

一种新型巯基胺型羧酸螯合树脂的制备与表征

以环硫氯丙烷和多乙烯多胺为原料,通过交联反应合成巯基胺型树脂(PA树脂).然后用氯乙酸对PA树脂进行改性,合成巯基胺型羧酸螯合树脂(PAC树脂),并通过傅里叶红外光谱仪(FTIR)和热重分析仪(TG)对其结构和热稳定性进行表征.研究溶胀时间、介质中含水量、物料比对反应的影响,获得了较佳的工艺条件.结果表明:以三乙烯四胺为原料合成的PAC3树脂的弱酸交换容量最高,达到3.53 mmol/g.     

Effects of type of polymerization catalyst system on the degradation of polyethylenes in the melt state. Part 1: Unstabilized polyethylenes (including metallocene types)

Several polyethylene resins namely, high‐density polyethylene (HDPE) (Phillips metal oxide catalyst) and linear low‐density polyethylenes (LLDPE) (formed by using Ziegler‐Natta and metallocene catalyst technologies), were used in order to acquire insight into the effect of different polymerization catalyst systems on the production of degradation products during melt processing. Infrared spectroscopy, color measurement, hydroperoxide determination, and melt flow rate measurement were used to monitor the degradation as a function of the number of passes through a twin‐screw extruder. The metallocene PEs were shown to exhibit superior melt stability relative to Phillips HDPE. The latter showed high levels of hydroperoxide formation. The superior thermo‐oxidative stability of the metallocene PEs was attributed to low levels of metallic catalyst residues, together with low vinyl unsaturation content. In all of the PEs examined, the rate of crosslinking was greater than that of chain scission. IR spectroscopy indicated that crosslinking (most prevalent in the Phillips HDPE) proceeded via the addition of macroradicals to vinyl unsaturation. The Ziegler‐Natta LLDPE showed an intermediate tendency for crosslinking but notable formation of trans‐vinylidene and the most noticeable color development. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers     

Rheology-processing-property relationships in tubular blown film extrusion. II. Low-pressure low-density polyethylene

An experimental investigation was undertaken to establish rheology-processing-property relationships in the tubular blown film extrusion of low-pressure low-density polyethylene (LP-LDPE). For the study, three commercial LP-LDPE resins, each from a different resin manufacturer, were used in producing tubular films, by employing the apparatus described in Paper I of this series. Both molecular and rheological characterizations of the resin were conducted, enabling us to interpret the tubular film blowing characteristics of the resins. Correlations were obtained between the processing variables (namely, blowup and takeup ratios) and the tensile properties of the films. The tubular film blowing characteristics of LP-LDPE and HP-LDPE resins are compared. Differences in the rheological properties (namely, elongational viscosity) of the two types of resin are used in explaining the experimentally observed differences in their tubular film blowability.