1,2,2,6,6-五甲基哌啶醇光稳定作用的研究

本文研究了1,2,2,6,6-五甲基哌啶醇在异辛烷溶液中的光稳定作用。实验结果表明:五甲基哌啶醇具有和四甲基哌啶醇基本相同,而此四甲基哌啶醇氮氧自由基略优的光稳定效率;五甲基哌啶醇和四甲基哌啶醇一样,在光稳定作用过程中产生氮氧自由基,并且氮氧自由基浓度变化经历了一个最大值,但其积累的速度及达到的浓度极大值均比四甲基哌啶醇的场合为低。实验还发现,五甲基哌啶醇在光稳定过程中产生一个稳定中间产物——N-氧化-1,2,2,6,6-五甲基哌啶醇。据此,提出了五甲基哌啶醇首先转化为N-氧化物,进而转化为氮氧自由基的两步作用机理。     

2,2,6,6-四甲基哌啶醇复合物的XPS研究

近年来,四甲基哌啶醇化合物(Ⅰ)(TMP)作为光稳剂被人们广泛研究,而这类化合物中的2,2,6,6位的四个取代甲基的存在正是其哌啶醇氮氧自由基(Ⅱ)稳定存在的重要原因。     

1,2,2,6,6-五甲基哌啶醇与紫外吸收剂和猝灭剂在对聚丙烯膜光稳定作用中并用效应的研究

<正> 最近的研究发现,五甲基哌啶醇与四甲基哌啶醇的光稳定机理有一定的不同。我们还观察到2,2,6,6-四甲基哌啶醇与2-羟基-4-辛氧基二苯甲酮(UV-531)同时添加到聚丙烯膜中具有明显的协同效应。本实验探讨了1,2,2,6,6-五甲基哌啶醇(PMP)与几种紫外吸收剂及猝灭剂的并用效应,并比较四甲基哌啶醇及五甲基哌啶醇与紫外吸收剂并用效应的差别。     

乙烯系单体自由基聚合的阻聚效应——ⅩⅣ.4-甲基丙烯酰氧基-2,2,6,6-四甲基哌啶-1-氧自由基低聚物的合成及对丙烯酸阻聚的研究

研究了数均分子量10~3～5×10~3的聚甲基丙烯酸甲酯的制备及其在甲醇镁存在下和2,2,6,6-四甲基-4-羟基哌啶-1-氧自由基(TMHPO·)间的酯交换反应,合成了聚-4-甲基丙烯酰氧基-2,2,6,6-四甲基哌啶-1-氧自由基(PMTMPO·)低聚物。同时观察了4-甲基丙烯酰氧基2,2,6,6-四甲基哌啶的调聚反应,同样制得PMTMPO·低聚物。利用IR、EPR和TGA技术对PMTMPO·进行了表征。评价了PMTMPO·对AIBN引发的丙烯酸(AA)自由基聚合的影响,表明PMTMPO·对AA有良好的阻聚功效。     

乙烯系单体自由基聚合的阻聚效应——ⅩⅣ.4-甲基丙烯酰氧基-2,2,6,6-四甲基哌啶-1-氧自由基低聚物的合成及对丙烯酸阻聚的研究

 研究了数均分子量10³～5×10³的聚甲基丙烯酸甲酯的制备及其在甲醇镁存在下和2,2,6,6-四甲基-4-羟基哌啶-1-氧自由基(TMHPO·)间的酯交换反应,合成了聚-4-甲基丙烯酰氧基-2,2,6,6-四甲基哌啶-1-氧自由基(PMTMPO·)低聚物。同时观察了4-甲基丙烯酰氧基2,2,6,6-四甲基哌啶的调聚反应,同样制得PMTMPO·低聚物。利用IR、EPR和TGA技术对PMTMPO·进行了表征。评价了PMTMPO·对AIBN引发的丙烯酸(AA)自由基聚合的影响,表明PMTMPO·对AA有良好的阻聚功效。     

4-(甲基丙烯酸)2,2,6,6-四甲基哌啶醇酯的合成

合成4-(甲基丙烯酸)2,2,6,6-四甲基哌啶醇酯的方法,在文献上报导甚少,T.Kurosaki 用甲基丙烯酰氯和2,2,6,6-四甲基哌啶醇在苯溶液里,在三乙胺存在下进行反应制得,产率只有27%。     

甲基丙烯酸正丁酯正相微乳液可控/“活性”光聚合动力学研究

以末端含溴原子的光引发剂2-溴异丁酰氧基-2-甲基-1-苯基甲酮(HMPP-Br)为引发剂,2,2,6,6-四甲基哌啶-1-氧自由基(TEMPO)和2,2,6,6-四甲基哌啶醇(TMP)为调控剂,采用光聚合方法研究了甲基丙烯酸正丁酯(n-BMA)/十二烷基硫酸钠(SDS)/水/正丁醇 O/W型正相微乳液体系的光聚合反应动力学.结果表明,改性后的引发剂具有一定的引发活性,且聚合微乳液体系较稳定,聚合反应获得了良好的ln[M]₀/[M]与时间、数均分子量与转化率之间的线性动力学关系,制备了分子量分布较窄的Poly(n-BMA)均聚物.     

新型受阻胺光稳定剂3-（2，2，6，6-四甲基哌啶4-氨基）丙酸十二酯的合成

建立了受阻胺光稳定剂3-(2,2,6,6-四甲基哌啶-4-氨基)丙酸十二酯的合成工艺.以2,2,6,6-四甲基-4-哌啶胺、丙烯酸甲酯为原料,经M ichael加成,生成的3-(2,2,6,6-四甲基哌啶-4-氨基)丙酸甲酯再与十二醇进行酯交换反应制得.并对所涉及的酯交换反应的工艺参数进行了优化.实验结果表明,四异丙基钛酸酯催化剂的催化效果最好;在3-(2,2,6,6-四甲基哌啶-4-氨基)丙酸甲酯与十二醇的摩尔比为1∶1.10,四异丙基钛酸酯催化剂的用量为反应物总质量的0.30%,反应温度180℃,反应时间8 h的条件下,酯交换反应收率为90.6%.该工艺总收率为86.3%.目标产物及中间体的结构通过MS进行了表征.     

用四甲基哌啶醇氮氧自由基化合物降低丙纶纺丝温度的研究

聚丙烯树脂中加入万分之几的2,2,6,6-四甲基哌啶醇氮氧自由基,可改善流动性能,使纺丝温度自330°降低至280°,得断裂强度为5克/(代糸)的聚丙烯长丝。     

基于四氮配体的铜配合物/TEMPO催化的苄醇与烯丙基醇的氧化反应

发展了非血红素类四氮配体的铜配合物和2,2,6,6-四甲基哌啶-氮-氧自由基(TEMPO)相结合的催化体系,应用于分子氧参与的伯醇氧化反应.该体系具有条件温和、高效、高选择性、无需任何助剂和底物(包括苄醇、烯丙基醇和含杂原子伯醇)使用性强等优点.此外,利用高分辨质谱和紫外-光谱等对反应活性中间体进行了初步探讨.     

2,2,6,6-四甲基哌啶醇和2-羟基-4-辛氧基二苯甲酮对聚丙烯膜光稳定作用的协同效应

<正> 受阻胺(2,2,6,6-四甲基哌啶的衍生物)是近年来发展起来的一类新型高效光稳定剂,它和其它稳定剂并用时的稳定效果和作用机理,是重要的研究课题.Allen研究了Tinuvin 770(癸二酸双(2,2,6,6-四甲基哌啶)酯)和一系列抗氧剂同时添加到聚丙烯膜中时的效应,指出其中许多抗氧剂和Tin.770都有显著的反协同效应;他的研究还表明,     

Extraction of polypropylene additives and their analysis by HPLC

Summary The polypropylene additives were extracted by dissolution-precipitation and Soxhlet. The Soxhlet method was adapted for the extraction of phosphorous antioxidants. The RP HPLC method with quaternary gradient elution separated five chemical groups of additives: lower molecular mass di-tert-butyl phenol (D.T.B.P.), hindered amine light stabilizers (Tinuvin 326), hindered phenolic antioxidants (Irganox 1010) and phosphorous antioxidants (Irgafos 168 and Ultranox 626) with their degradation products.     

HALS和抗氧剂对PE辐射致色的影响

聚乙烯;稳定剂;HALS和抗氧剂对PE辐射致色的影响     

Effect of stabilizers on the preparation of poly(ethylene terephthalate)

Previous investigators have indicated that stabilizers will block the transesterification catalyst in the preparation of PET by the DMT process. This was not the case when triphenyl phosphate (TPP) or Irganox 1010 was used as the stabilizer and manganous acetate as the catalyst. Stabilizers in this study included TPP, trimethyl phosphate (TMP), tetraethylammonium hydroxide (TEAOH), Irganox 1010, and Irganox 1222. Their effect on the properties of PET made by the TPA process was investigated. It was observed that TPP and TMP greatly reduced the carboxyl content of PET and that the others had little or no effect. All stabilizers lowered the diethylene glycol content of PET. The rate of polycondensation was slightly increased when a small amount of Irganox 1010, Irganox 1222, or TMP was added. Proper concentration of stabilizer should be chosen to obtain good stability and low diethylene glycol content. Among the five stabilizers studied TPP was the best with respect to carboxyl and diethylene glycol content and thermal stability. The concentration of TPP should be kept under 0.04% by weight of PET.     

ANTIOXIDANT DEPLETION AND OIT VALUES OF HIGH IMPACT PP STRANDS

The service life of a polyolefin product depends to large extent on the type and amount of the antioxidants added. During the manufacturing,storage and use of the product the antioxidants are depleted by physical processes and chemical degradation,and this impairs its long-term performance.The initial and in-use oxidation stability is often characterized and monitored by the measurement of the oxidative induction time(OIT),and service life predictions are based on the rate of decrease of the OIT value.To...     

Kinetic Evaluation of Reactivity of Phenolic Derivatives as Antioxidants for Polypropylene

Reactivity of commercial phenols as antioxidants for plastics, especially polypropylene, was examined under kinetic considerations. Inhibitive rate constants, k_inh, were found to decrease in the order: SWP ? Topanol CA ? BMP > Ionox 330 > Irganox 1076 > Irganox 1010, while numbers n′ of free radicals trapped by the phenolic moiety decreased in the order: Irganox 1076 > Irganox 1010 ? Ionox 330 > BMP ? Topanol CA > SWP (the structures of these antioxidants are given in the text). In practical use of phenols for polypropylene, it was found that effective phenols are not those having higher values of of k_inh., but n′ values nearly two. The effect of substituents, especially para substituents, of phenols on their activities was elucidated.     

Irradiation of Polyethylene in Presence of Several Additives as Studied by Chemiluminescence

Abstract

The protecting effect against radiation induced oxidation of poly-ethylene provided by several additives, namely pyrene, Irganox 1222 and Irganox 1010 has been investigated by mean of FTIR spectroscopy and chemiluminescence (CL) technique. Pyrene appears to be more effective and more stable to irradiation than phenolic antioxidants. Thus, about half of initial pyrene seems to remain unchanged after an exposure of the material to γ⁶⁰Co rays at 240 kGy (dose rate 1 kGy/h) in presence of air. Under the same conditions, about 90% of initial Irganox 1010 seems to be consumed as indicate a comparison of induction oxidation times of initial and irradiated material. The stabilizing effect of the residues resulted by pyrolysis at 850°C in inert atmosphere of several polymers, such as polyacrylonitrile, polyvinylchloride and methyl cellulose is discussed as well.     

The effects of gamma irradiation on the fate of hindered phenol antioxidants in food contact polymers. Analytical and 14C-labelling studies

The extractable levels of two hindered phenol antioxidants (Irganox 1076 and Irganox 1010) present in PVC, polyethylene and polypropylene, have been monitored by HPLC techniques following progressive exposure of the polymers to ⁶⁰Co γ radiation. There is a gradual diminution in the extractable levels of each antioxidant as irradiation progresses as a result of transformation of the antioxidants in the oxidation reactions ensuing during irradiation. Experiments involving the use of a ¹⁴C-labelled sample of Irganox 1076 in polyolefins have provided evidence of covalent binding of antioxidant degradation products to the polymer following gamma irradiation. However, there is also evidence of the formation of extractable degradation products, the identity of which is as yet unknown.     

Photo-stabilization of styrene-butadiene copolymer: The effect of 2,2′-thiodiethylbis-[3-(3,5-di-tert-butyl-4-hydroxy-phenyl)propionate] on the photo-sensitized oxidation of styrene-butadiene copolymer

The effect of 2,2′-thiodiethylbis-[3-(3,5-di-tert-butyl-4-hydroxy-phenyl) propionate] (Irganox 1035) on the 9-methylanthracene sensitized photo-oxidation of styrene-butadiene copolymer (SBR) has been examined. It was found that the photo-oxidation of SBR is considerably inhibited by the Irganox. Irganox was found to be able to quench singlet oxygen as well as to scavenge alkoxyl radicals.