The effect of grafted TMPM on the radiation resistance of polypropylene

The γ‐radiation–induced graft copolymerization of 2,2,6,6‐tetramethyl‐4‐piperidinyl methacrylate (TMPM) onto polypropylene (PP) was investigated using a simultaneous‐irradiation technique. The effects of solvents, atmospheres, dose, and monomer concentration on the percent of grafting were studied. The grafted TMPM showed better thermal stability, solvent extraction resistance, and compatibility with PP than monomeric TMPM or polymeric PTMPM. The stabilizing effectiveness of grafted TMPM on the radiation resistance of PP was found to be better than that of monomeric TMPM. The combination of grafted TMPM and low molecular weight hindered amine light stabilizers showed higher stabilizing effectiveness. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2150–2157, 1999     

新型受阻胺类光稳定剂N-烯丙基四甲基哌啶醇的合成和表征

在Mg-Al水滑石(Mg-Al LDHs)催化哌啶醇和烯丙基溴反应,合成了一种新型受阻胺类光稳定剂,产物通过IR、MS、元素分析等进行了表征。     

多功能型聚合物稳定剂的研究进展

多功能化是聚合物添加剂发展的重要趋势之一,在同一分子中引入不同功能性的基团,是实现多功能化的主要途径。本文对该类稳定剂的合成和应用进行了综述,简要介绍了其中一些品种,如苯并三唑-受阻酚型、受阻胺-受阻酚型、受阻胺-二苯酮型、受阻胺-苯并三唑型、硫酯类-抗氧剂型、偶联剂-受阻酚-抗氧剂型等。     

高分子量受阻胺光稳定剂BW-10LD在聚乙烯棚膜中的应用

介绍了研制开发的新一代高分子量受阻胺光稳定剂ＢＷ－１０ＬＤ（相当于国外ＴｉｎＵ－ｖｉｎ６２２ＬＤ）。它具有优异的热稳定性，与亚磷酸酯ＰＬ－１０、ＰＬ－４４０配合用作聚乙烯棚膜的防老化体系大田应用试验效果良好。     

Online monitoring of the influence of the chemical structure of hindered amines on the hydrolysis of polycarbonate in a polycarbonate/poly(acrylonitrile–butadiene–styrene) blend by ultraviolet–visible spectroscopy

Without stabilization, polycarbonate (PC)/poly(acrylonitrile–butadiene–styrene) (ABS) blends are susceptible to a loss of mechanical properties after a few days of exposure to weathering conditions. ABS can be stabilized against terrestrial light by the use of hindered amines in combination with a UV absorber; such hindered amines cannot be used when PC is present in the polymer blend. The hydrolysis of PC is accelerated when a small amount of a hindered amine light stabilizer (HALS) is incorporated into the resin and is exposed to elevated temperatures. In this study, three different HALSs (Tinuvin 123, Tinuvin 770, and Tinuvin 765, Ciba, Basel, Switzerland) were used as UV stabilizers for PC/ABS blends, and their effects on the PC phase were observed with online ultraviolet–visible spectroscopy on extruded flat films. These stabilizers were compounded with the blends in a corotating twin‐screw extruder at 240°C. The molecular weight of the compounded samples was determined by gel permeation chromatography. The extent of degradation induced by the HALSs on the PC phase was found to be a function of its chemical structure. Tinuvin 123 with an amino ether functional group enhanced degradation in comparison with Tinuvin 770 and Tinuvin 765. Tinuvin 770, a secondary amine, was apt to be more reactive than Tinuvin 765, a tertiary amine, because less steric hindrance was experienced by the former. Accelerated aging of the compounded samples was performed. Decreased degradation was observed for the samples containing hindered amines; however, the HALSs alone were not effective in protecting the PC/ABS blends against harmful UV light. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

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。     

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     

聚甲醛、PET及PVC的抗老化配方研究进展

综述了聚甲醛(POM)、PET、PVC及其改性材料的抗老化研究的新进展。POM、PET及PVC/ABS的抗老化配方采用抗氧剂/紫外线吸收剂复配体系,而PVC及其他改性材料则采用紫外线吸收剂体系,若再加入适量的受阻胺光稳定剂,可以改善材料的抗老化效果。     

Comparison of photo-oxidative degradation of polyamide 6,6 films stabilized with HALS and CuCl2+KI mixtures

The photo-oxidative stability of polyamide 6,6 (PA 6,6) doped with a hindered amine light stabilizer (HALS) and a mixture of cupric chloride and potassium iodide was examined.Several analytical techniques were employed, in order to evaluate the correlation between chemical modifications, morphology and mechanical properties of PA 6,6 films irradiated at λ>300 nm, 90 °C, and 50% relative humidity.Infrared spectroscopy showed a build-up of carbonyl absorption in the range 1700-1780 cm⁻¹ due to primary and secondary photo-oxidation products. The increase in content of carbonyl groups was greatest in the case of the pure polymer, and it was also appreciable in the case of PA 6,6 stabilized with copper/KI system. On the other hand, the use of the HALS additive brought about a substantial increase in the amount of carboxylic acids formed.The morphology of the samples was found to have an effect on the kinetics of the accumulation of carbonyls, and it was observed that at a later stage of exposure the crystalline phase was also involved in the oxidation process.Tensile tests on films revealed a large reduction in ductility as a result of ageing for both neat polymer and HALS-doped polymer. Only a slight reduction in ductility was found for the polymer stabilized with the inorganic mixture.This study evidenced that the mixture of CuCl₂ and KI has a far better long-term stabilizing efficiency in comparison with the HALS stabilizer.     

Kinetic Study of Hindered Amine Light Stabilizer Photografting in Poly(propylene) Films under Natural Weathering and Accelerated UV Conditions: Effect of Additive Concentration

Full Paper: The objective of this work is aimed at determining the kinetics of HALS photografting in PP films as a function of the additive concentration under both natural weathering and accelerated UV conditions. The stabilizer studied had a single structure that combined HALS and a UV absorbing unit detectable at 308 nm in the UV spectrum of PP, capable of inducing a photoreaction with the polymer matrix. The kinetics of HALS photografting on PP films at various additive concentrations was determined by direct spectroscopic measurements on film samples through the absorption band of the stabilizer positioned at 308 nm in the UV spectra, which was attributed to the highly conjugated methylenic double bond. The content of free HALS was determined as a function of exposure time by UV spectroscopy for all the additive concentration ratios used. It is shown that the kinetics of HALS photografting increase with a decrease in the additive concentration ratio. The whole grafting process under conditions of natural weathering occurred in the PP film after almost 350 h of exposure, while approximately 20 h were necessary under accelerated UV conditions. Moreover, these kinetics are well described by a third order polynomial model, validated by a maximum value of the coefficient of correlation close to unity. This was also confirmed by a comparison of the time values measured at 50% of the total grafting calculated from the model with those observed experimentally. This finding was consistent with the data obtained on the free HALS content determined by UV spectroscopy.

The percentage of HALS photografting in PP films as a function of time under natural weathering, determined by UV spectroscopy.