HALS研发进展及其在PVC中的应用

介绍了近年来受阻胺类光稳定剂(HALS)新产品的研究开发情况,高分子量化受阻胺、多功能化受阻胺、低碱性化受阻胺和反应型受阻胺等不断出现;应用研究取得新进展,对PVC体系中有较好稳定的作用。     

受阻胺类光稳定剂的发展

详细介绍了受阻胺类光稳定剂（HALS）的作用机理及国内外发展现状，指出应向高分子量化发展，开发低碱性HALS及反应键合型HALS。     

Polymer bound HALS-expectations and possibilities

The work confronts the traditional opinion on the physical aspects of the HALS efficiency with the available experimental reality. The results indicate that the generally accepted importance of additive's migration may need to be reconsidered. Based on the experimental evidence, three empirical requirements for an effective stabiliser are formulated: high solubility, minimal diffusion, high homogeneity of distribution of active species. Chemical grafting of a low molecular stabiliser is suggested to meet the defined empirical requirements. The results achieved with the polymer bound HALS (PBH) prepared by reactive processing technology confirm the expectations. The stabilisation efficiency of PBH significantly outperforms the conventional low molecular and oligomeric stabilisers.     

各类稳定剂对聚乙烯薄膜光氧老化的稳定作用

研究了不同光稳定剂和抗氧剂及其配合使用、光稳定剂含量对聚乙烯薄膜耐光氧老化性的影响。结果表明：在各类光稳定剂中、受阻胺类稳定剂的效果最好;紫外线吸收剂与受阻胺配合使用可使膜的耐老化性有所提高;各类抗氧剂对聚乙烯膜的耐光氧老化性没有不利影响;光稳定剂含量增加,薄膜耐老化寿命提高。     

聚合物抗氧剂结构与抗氧性能关系

介绍了胺类、酚类、亚磷酸酯类、硫类及天然抗氧剂的结构与抗氧性能的关系,及各个官能团在抗氧剂中的作用,并展望了国内外抗氧剂的发展。     

受阻胺类光稳定剂改性文物保护材料B72

为了提高B72文物保护材料的耐光性能,采用HALS-622等6种受阻胺光稳定剂对丙烯酸类文物保护材料B72进行改性。结果表明,HALS-5060稳定剂在添加后及老化过程中颜色明显变黄,不宜用作B72改性材料。高相对分子质量(简称分子量,以下同)受阻胺HALS-622、HALS-944比低分子量受阻胺HALS-480、HALS-508和HALS-292稳定效果好,尤其是低碱性的HALS-622受阻胺。因此,采用高分子量、低碱性的受阻胺改性B72是延长其使用寿命、对文物进行有效保护的新途径。     

受阻胺光稳定剂的生产与研究进展

介绍了国内外受阻胺光稳定剂（HALS）的生产状况,包括HALS的主要系列、品种、产量和需求情况。阐述了HALS的研究现状与发展趋势,指出该领域正向高相对分子质量化、多功能化、低碱化反应性方向发展,并提出了国内HALS产业发展的一些建议。     

Effect of hindered piperidine light stabilizer molecular structure and UV‐absorber addition on the oxidation of HDPE. Part 1: Long‐term thermal and photo‐oxidation studies

This series of papers explores the effect of structural characteristics of 2,2,6,6‐tetramethylpiperidine‐based hindered amine light stabilizers (HALS) on the long‐term (40 months) thermal (110°C in air) and photo‐stabilization (Microscal unit wavelength >300 nm) performance characteristics of high‐density polyethylene formulations. Possible synergism with a triazine functional UV absorber is also explored. Under thermal degradation (measured by carbonyl index) the polymeric HALS performed best, mainly because of reduced volatilization. Additionally, >N‐methyl HALS generally showed superior performance under thermal degradation. There was no synergism between an N‐CH₃ polymeric HALS and the UV1164 triazine additive. However, the equivalent N‐H polymeric HALS interacted in a complex manner with UV1164, giving synergism and antagonism, depending on HALS/UV1164 ratio. Strong synergism was evident with the monomeric HALS when the total stabilizer level was 0.2% w/w. Reduction in the overall stabilizer level to 0.05% w/w eliminated the synergism. The UV1164 alone led to rapid and intense yellowing; however, the rate and intensity of yellowing reduced dramatically upon combination with HALS, particularly when the UV1164 level was above 0.1% w/w. When the formulation was under UV attack, the molar mass and the type of N‐substitution had no influence on stabilization performance because of the relatively low temperature of testing (leading to reduced volatilization), and the similarly effective UV‐stabilization routes for N‐methyl HALS and N‐H HALS. Under UV attack, yellowing reached a maximum and then decreased to approximately the initial level, while HALS/UV1164 combinations generally showed weak antagonism. J. Vinyl Addit. Technol. 10:79–87, 2004. © 2004 Society of Plastics Engineers.     

加氢润滑油基础油光稳定剂的研制

应用正交试验设计的方法,研究了自制的紫外辐射吸收剂、受阻胺类光稳定剂及抗氧剂对兰州石化总厂生产的125N加氢润滑油基础油抗光氧化降解性能的影响.发现以上各种添加剂均能提高加氢润滑油基础油抗光氧化降解的能力.在相同的辐射剂量下,添加四甲基受阻胺类光稳定剂的加氢基础油抗光氧化降解的能力优于添加五甲基受阻胺类光稳定剂;添加苯并三唑型紫外辐射吸收剂比添加二苯甲酮型紫外吸收剂的加氢基础油抗光氧化降解的能力强;紫外辐射吸收剂与受阻胺类光稳定剂之间以及紫外辐射吸收剂与抗氧剂之间均存在协同作用.并且发现,四甲基受阻胺类光稳定剂与酚类抗氧剂之间存在协同作用,而五甲基受阻胺类光稳定剂与酚类抗氧剂之间存在反协同作用.评价结果表明:添加自制的高效无灰复合型光稳定剂1.5g·L-1可使兰州炼油化工总厂生产的125N加氢润滑油基础油保持良好的光稳定性,其透光率、色度均优于添加2 g·L-1目前最好的有机镍盐配合物型光稳定剂.     

Factors influencing the adsorption of stabilizers onto carbon black: Flow microcalorimetry studies

The surface activity of various kinds of carbon black toward phenolic antioxidants and hindered amine light stabilizers (HALS) was examined by using flow microcalorimetry (FMC). Phenolic hydroxyl and ester groups were found to be the moieties responsible for the adsorption activity of primary phenolic antioxidants onto the carbon black surfaces. Furthermore, a difference in the degree of phenolic hydroxyl hindrance by alkyl groups was found to be the main factor affecting the adsorption activity of the phenol group. A difference in the degree of substitution of the piperidine amine, as well as the number and type of functionality per molecule, are important factors that were found to influence the adsorption activity of HALS. Data from adsorption studies using model compounds, some of which represented functional portions of the stabilizer molecules, reflected behavior sin ilar to that observed with the stabilizers. In addition, these latter results showed that FMC analysis can yield potentially useful information beyond that given by the usual parameters such as BET surface area, I₂, DBP, and CTAB adsorption values. Differences in the behavior between types of carbon black were evident and showed that the specific surface area is not the most important factor in the adsorption/desorption activity, but also the chemical nature of the surface. From the activity observed for model compounds, it was deduced that the presence of secondary and tertiary amine in the backbone and branch structures also has an important role in the adsorption activity of polymeric HALS. In general, the observed quantities can be related to the values of adsorption/desorption energy and to the molar mass of the probe.     

受阻胺光稳定剂的研究进展

综述了国内外受阻胺光稳定荆（HALS）的研究现状与发展趋势,指出该领域正向高相对分子质量化、多功能化、低碱化、反应性方向发展。并提出了国内HALS产业发展的一些建议。     

聚甲醛耐光稳定性研究进展

综述了聚甲醛光氧老化特性和光稳定剂研究开发现状,指出了聚甲醛光稳定剂未来发展趋势。聚甲醛对抗紫外光稳定性较差,容易发生降解与氧化,添加光稳定剂有助于提高聚甲醛耐光稳定性。常用的聚甲醛光稳定剂主要包括紫外光屏蔽剂、紫外光吸收剂和受阻胺类光稳定剂等三大类,对光稳定剂的研究方向主要包括高相对分子质量化、聚合物键合化、多功能化、受阻胺低碱性化等方面。     

Chemiluminescence study of thermal and photostability of polyethylene

The oxidation stability of low density polyethylene to UV light has been studied in the presence of various types of antioxidants (hindered phenols, HALS and synthetic N-alkylamines). A chemiluminescence procedure has been applied. Kinetic parameters of oxidation are obtained from isothermal measurements at 180 °C. The synergistic effect of antioxidant couples is examined and a stabilisation order is determined. © 1999 Society of Chemical Industry     

Organophosphorus antioxidants action mechanisms and new trends

Phosphite and phosphonite esters can act as antioxidants by three basic mechanisms depending on their structure, the nature of the substrate to be stabilized and the reaction conditions. All phosph(on)ites are hydroperoxide-decomposing secondary antioxidants. Their efficiency in hydroperoxide reduction decreases in the order phosphonites > alkylphosphites > arylphosphites > hindered arylphosphites. Five-membered cyclic phosphites are capable of decomposing hydroperoxides catalytically due to the formation of acidic hydrogen phosphates by hydrolysis and peroxidolysis in the course of reaction. Hindered aryl phosphites can act as chain-breaking primary antioxidants being substituted by alkoxyl radicals and releasing hindered aryloxyl radicals which terminate the radical chain oxidation. At ambient temperatures, the chain-breaking antioxidant activity of aryl phosphites is lower than that of hindered phenols, because the rate of their reaction with peroxyl radicals and their stoichiometric inhibition factors are lower than those of phenols. In oxidizing media at medium temperatures, however, hydrolysis of aryl phosph(on)ites takes place giving hydrogen phosph(on)ites and phenols which are effective chain-breaking antioxidants. 2,2,6,6-Tetramethyl- and 1,2,2,6,6-Pentamethylpiperidinyl phosphites and phosphonites (HALS-phosph(on)ites) surpass many common phosphites, phenols and HALS compounds as stabilizers in the thermo- and photo-oxidation of polymers. Their superior efficiency is probably due to an intramolecular synergistic action of the HALS and the phosph(on)ite moieties of their molecules.     

Synergistic profiles of chain‐breaking antioxidants with phosphites and hindered amine light stabilizers in styrene–ethylene–butadiene–styrene (SEBS) block copolymer

The photostabilization of poly(styrene‐b‐ethylene‐co‐butylene‐b‐styrene) (SEBS) by phosphite/p‐hydroxybenzoate antioxidants and hindered phenol/hindered amine light stabilizers (HALS) was studied by using a variety of spectroscopic methods, including FTIR, UV, and luminescence spectroscopy coupled with crosslinking and hydroperoxide analysis. The results were compared with those obtained for hindered phenols and their combinations with phosphite antioxidants. All the stabilizing packages stabilized the SEBS in terms of the inhibition of discoloration and the formation of hydroperoxides, acetophenone, and oxidation products, as well as chain scission and disaggregation of the styrene units. Although phosphite/p‐hydroxybenzoate combinations appeared to reduce the formation of oxidation products, they did not show any remarkable enhancement in long‐term stabilization with respect to phenolic/phosphite antioxidants. On the other hand, strong synergistic profiles were found with the HALS. Mobility and diffusion impediments in the polymeric material appeared to play an important role in the stabilizing activity of the HALS. J. VINYL. ADDIT. TECHNOL. 12:8–13, 2006. © 2006 Society of Plastics Engineers     

受阻胺光稳定剂和抗氧剂并用对聚合物紫外光稳定性的影响

阐述了受阻胺稳定剂(HALS)和抗氧剂的分类和作用机理,重点介绍了受阻胺类光稳定剂和抗氧剂并用对聚合物紫外光降解中的影响。当受阻胺类光稳定剂和抗氧剂并用时,既有协同效应,又有对抗效应,也有加和效应。这依赖于受阻胺类光稳定剂和抗氧剂的种类。同时介绍受阻胺光稳定剂发展的趋势。     

耐药型受阻胺光稳定剂的发展

介绍了耐药型受阻胺光稳定剂（HALS）的发展。针对低pKa值HALS,含缚酸剂的HALS,以及N-烷基化和N-烷氧基化HALS,详细叙述了典型品种的性能特点,并报道了耐药型受阻胺光稳定剂的最新研究成果。     

Study of natural aging of industrial low density polyethylene by X-ray photoelectron spectroscopy

Abstract

X-ray photoelectron spectroscopy (XPS) was used to study the natural outside aging of industrial low density polyethylene (LDPE) under the influence of one year round weather. Two types of LDPE were studied. The first type was LDPE without additives and the second type was doped with 4% of hindered amine light stabilisers (HALS). Unstabilised and 4% HALS stabilised LDPE samples underwent an oxidation of the polymeric matrix, by the production of C–O, C=O and O=C–O groups. These chemical functions were observed in high resolution XPS spectra around C1s and O1s peaks. From these results, it was then possible to propose mechanisms of natural aging of LDPE in such conditions. On the other hand, there is no clear evidence that HALS could be effective in natural aging for the polymer surfaces with exposure to the elements.     

Theoretical and experimental assessment of UV resistance of high-density polyethylene: Screening and optimization of hindered amine light stabilizers

Hindered amine light stabilizers (HALS) are widely used chemical stabilizers for preventing polymer degradation. In this study, the effects of type of HALS and its content in high-density polyethylene (HDPE) over the stabilization process are investigated employing density functional theory (DFT) and experimental approach. The electrophilicity index of four types of commercial HALS are compared by DFT to select the most effective one. Besides, the HDPE sample containing a phenolic antioxidant and different contents of the selected HALS are experimentally exposed to UV irradiation. The effect of HALS content on the changes in chain microstructure and molecular weight of HDPE are evaluated using gel permeation chromatography and frequency sweep rheometry. In the absence of HALS, HDPE suffers degradation and the phenolic antioxidant causes chain scission. However, by adding HALS, the chain branching and crosslinking mechanisms are predominant. The results of FTIR, DSC, and tensile analyses follow similar trends, revealing that the best stabilization performance corresponds to adding 600 ppm HALS to HDPE.     

Synergistic efficiency of combined HALS–UV absorber polymerizable stabilizers

The influence of combined 2,2,6,6‐tetra methylpiperidine ? 2‐hydroxyphenyl‐benzotriazole [1,3,5]triazine polymerizable stabilizers on the photostability of their copolymers with methyl methacrylate as well as the interaction of the photoreactive HALS and UV absorber fragments in the combined molecules have been studied. Chemical bonding of the stabilizers in the polymer was confirmed spectrophotometrically. The participation of the combined stabilizers in the polymerization did not affect considerably the molecular weight and the molecular weight distribution of the copolymers. A significant stabilizing effect against photodegradation was determined. Strong synergistic interaction between different HALS and UV absorber fragment in the combined stabilizers was established. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2408–2415, 2006