含羟酸稀土光敏剂降解PVC塑料的可降解研究

以羧酸共生稀土作为PVC塑料紫外光氧化降解的光敏剂,采用人工加速老化实验、户外曝晒实验等方法进行降解试验,并用红外光谱,紫外光谱和凝胶色谱等方法对含羟酸共生稀土光敏剂可降解PVC塑料的可降解性能进行了研究。初步探讨了羧酸共生稀土敏化PVC膜光氧化降解的作用机理。结果表明,羟酸共生稀土（如La、Ce、Pr等）对PVC分子的结构具有明显的光敏化降解作用,并具有抑制PVC在光照过程中发生交联的作用。     

羧酸稀土配合物的合成及其对LDPE膜和农膜光敏化效果的研究

合成了６种羧酸和羧酸混合稀土配合物。通过元素分析，热重－差热分析、红外光谱和紫外光谱研究了它们的组成和性质，用红外光谱法测定了含羧酸铈或羧酸共生稀土的低密度聚乙烯ＵＶ光氧化羰基指数，研究了羧酸铈和羧酸共生稀土对ＬＤＰＥ膜ＵＶ光氧化速度及其粘均分子量的影响，并探讨了它们在敏化ＬＤＰＥ膜光氧化降解方面的作用机理。     

含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解

含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解林宜超（福建省测试技术研究所福州３５０００３）近年来，许多作者先后研究并开发出含硬脂酸铈（ＣｅＳｔ３）光敏剂的可控光降解低密度聚乙烯（ＬＤＰＥ）［１，２］、高密度聚乙烯［３］、聚丙烯［４］、聚苯乙烯...     

可降解塑料与环境保护

近年来可降解塑料解决生态环境的白色污染问题受到普遍关注。推广使用可降解塑料,具有绿色环保意义。本文阐述了可降解塑料的分类、降解原理及国内外可降解塑料技术发展的现状,拟对其在我国的应用做一综述。     

稀土PVC稳定剂的作用机制研究

稀土化合物可以作为聚氯乙烯稳定剂，硬脂酸稀土是稀土复合稳定剂的重要成分。本文通过研究PVC与硬脂酸镧及其它硬脂酸盐作用前后的红外光谱，探讨了硬脂酸盐对PVC的热稳定作用机制，发现了稀土化合物对PVC的特殊稳定机制，即改变PVC的构象和抑制脱氯化氢的作用，并对稀土稳定剂独特的协同作用做出了解释。     

治理塑料废物新技术途径探讨——专论可降解塑料的研究开发

综述了可降解塑料的研究开发现状及其进展。可降解塑料的降解时控性研究,合成、加工工艺改进以及降低成本的研究, 可控光-生物降解的全面降解性研究和一次性使用塑料(包括地膜、包装材料和餐具等) 实用性研究, 仍是今后需深入探讨的重要研究课题。文中强调, 该项技术开发的首要前提是制订降解塑料及其降解性的术语定义并建立其降解性的评价试验方法。     

羧酸对复合羧酸镧热稳定剂性能的影响

以常见的一元羧酸、二元羧酸、三元羧酸和硝酸镧为原料,合成复合羧酸镧热稳定剂,采用刚果红法对产品对PVC的静态热稳定性进行表征,探讨不同羧酸之间的协同效应,进而通过转矩流变仪法对产品对PVC的动态热稳定性进行测试,并通过红外光谱对产品结构进行表征。结果表明:一元羧酸和二元羧酸之间的协同效应最好,且以硬脂酸/己二酸镧性能最佳,对PVC的动态热稳定性可达1420 s。     

含二苯甲酮结构的稀土配合物对PVC光稳定性能的影响

兼具热和光稳定性的稀土稳定剂,对降低聚氯乙烯(PVC)加工成本,提高PVC的生产效率和打开稀土稳定剂的应用领域具有重要的意义,因此,通过人工加速紫外老化实验和户外自然光老化实验,研究了2,4-二羟基二苯甲酮镧(LBP)、 2-苯甲酰苯甲酸镧(LBA)及三元复合稳定剂对PVC光稳定性能的影响。结果表明：添加含LBP和含LBA的两种三元复合稳定剂(LBP∶ZnSt₂∶PE=2∶1∶2, LBA∶ZnSt₂∶PE=1∶1∶3)的PVC片材,人工紫外老化10 d后,失重率分别为2.7%和6.2%,自然光老化35 d后,拉伸强度保留率分别为87.6%和81.8%,复合稳定剂提高PVC的光稳定性能最佳。稀土稳定剂可以吸收PVC降解产生的氯化氢,降低氯化氢的浓度,从而减弱氯化氢对PVC降解的催化作用,抑制PVC脱去HCl形成双键,防止双键在氧作用下,形成过氧化物生成羰基化合物。     

热裂解-气相色谱-质谱法鉴别生物可降解塑料

目前生物可降解塑料主要采用堆肥降解测定其生物降解性能的方法进行鉴别,其检测周期长、费用较高。材料的组成基本决定了其生物降解特性,为了快速鉴别生物可降解塑料,采用热裂解-气相色谱-质谱法(PY-GC-MS)对以聚对苯二甲酸-己二酸丁二醇酯(PBAT)与不同质量比的其他成分包括生物可降解聚乳酸(PLA)、难降解材料聚苯乙烯(PS)或聚对苯二甲酸乙二醇酯(PET)混合样的裂解特征进行了研究。结果显示,PBAT的裂解特征峰明显,未受到PLA的影响;若在PBAT中添加质量分数1%的非降解材质PS和PET也可被检出。方法用于市场上收集到的标识为可降解塑料购物袋样品的分析,结果表明,采用PY-GC-MS可以快速对可降解塑料进行初步鉴别。     

羧酸稀土配合物共聚反应的研究

通过沉淀法和直接法制备羧酸稀土配合物，与丙烯酸等单体共聚反应制备不同稀土含量的稀土有机高分子离聚物。用微量热天平(TG)、差热分析仪(DTA)等分析它的热稳定性以及玻璃化转变温度，用红外光谱分析其结构。讨论了用不同方法合成的稀土配合物对共聚反应和聚合物性能的影响。结果显示直接合成羧酸稀土配合物有利于共聚物性能的稳定和稀土含量的调节。     

Functional aspects of secondary carotenoids in Haematococcus lacustris [Girod] Rostafinski (Volvocales) IV. Protection from photodynamic damage

The function as an antioxidant seems to represent the central principle of chemopreventive activity of carotenoids against cancer initiation and promotion. The aim of this study was to clarify whether or not extrachloroplastic-accumulated secondary carotenoids (astaxanthin, canthaxanthin and echinenone) of Haematococcus lacustris [Girod] Rostafinski exhibit a similar antioxidative activity in protecting the cell of this green alga from photo-oxidative damage. In vivo experiments were performed, investigating the effect of UV radiation, artificial photosensitizers (rose bengal, toluidine blue) and copper-mediated lipid peroxidation on suspensions of flagellates which contained different amounts of secondary carotenoids. The results revealed a higher resistance of red flagellates to photo-oxidative stress. The findings are discussed with respect to the shading function of secondary carotenoids and known protective mechanisms involving quenching of reactive oxygen species and radical reactions in plant cells. A hypothesis for this functional aspect of secondary carotenoids in H. lacustris preventing injury by excessive insolation is suggested: ketocarotenoids, first accumulated in lipid vacuoles around the nucleus, might act as a physico chemical barrier, protecting particularly the genome from free radical-mediated damage.     

Effect of lubricants on the photo-oxidative degradation of solid poly(vinyl chloride)

Various commercially employed lubricants, such as low molecular weight polyethylene (Type PA-520 Wax), hydroxystearic acid (Loxiol G-21), butyl stearate (Loxiol G-32) and di-stearyl phthalate (Loxiol G-60), have been examined for their active rôle in the photo-oxidative degradation of poly(vinyl chloride) (PVC). The results show that low molecular weight polyethylene has an obvious accelerating effect on the photo-oxidative degradation of PVC, whereas other lubricants reduce the effect of photo-oxidation. None of the lubricants used has an obvious rôle in the chain scission and crosslinking of PVC.     

Photo-degradation and photo-stabilisation of the two-phase system poly(vinyl chloride)-polybutadiene

The photo-oxidative degradation of poly(vinyl chloride) (PVC)/polybutadiene (PB) blends has been studied. After uv irradiation, photo-grafting of the PVC and PB phases was observed. Photolysis of PVC accelerates cis-trans isomerisation of PB. Both phases, PVC and PB, are photo-degraded according to free radical oxidation mechanisms. The rates of these processes can be decreased by the addition of metal chelates, such as commercially produced Cyasorb uv light absorber 1084 (2,2′-thiobis(4-t-octylphenolato)-n-butylamine nickel(II)) and Cyasorb uv light absorber 2548 (cobalt dicyclohexyldithiophosphinate).     

气相色谱-负化学离子源质谱法测定聚氯乙烯塑料中的短链氯化石蜡

建立了用于聚氯乙烯(PVC)塑料中短链氯化石蜡(SCCPs)含量测定的气相色谱-负化学离子源质谱法。采用超声萃取法对PVC塑料中的SCCPs进行萃取,萃取时间为1.5 h;然后用浓硫酸法对萃取溶液进行净化处理;最后用气相色谱-质谱法在负化学电离模式、离子源温度为160 ℃、甲烷反应气流速为1.5 mL/min等条件下对样品中的SCCPs进行定性定量分析。该方法不受样品中中链氯化石蜡(MCCPs)的干扰,可对样品中的SCCPs进行准确的定量分析。分析的12批次样品均检出SCCPs,含量在0.3×10²~3.5×10⁴mg/kg范围内。依据欧盟对SCCP的限值(1%)要求,4批次样品不符合法规要求,不符合率为33.3%。可见,PVC塑料具有较高的SCCPs污染风险。     

Raman Analysis of Polymerization of APST Molecule

In this work we investigated the solidification of aminopropylsilanetriol dissolved in water (∼25%) under different conditions by Raman spectroscopy. The solidification was carried out at three different temperatures 8 °C, 23 °C and 60 °C. The influence of electromagnetic radiation on the polymerization process was also studied. Samples were held to solidify in dark and at UV (254 nm and 356nm) spectral range. In order to investigate the influence of the substrate on the resulting polymer structure, teflon, PVC, glass, brass and silica were used. Best ordered polymerized structure was achieved for samples deposited on plastics and solidified in dark, at room temperature.     

Mixing of polyvinylchloride plastics with ethylene-vinyl acetate copolymer

Rheological behavior of several types of polyvinyl chloride (PVC) plastics and ethylene — vinyl acetate copolymer (EVAC) is studied. The plots of flow obtained allows to conclude that principally is possible to create quality pigment concentrates based on EVAC for application at the colorization of PVC plastics.     

Studies on modified benzotriazoles as photostabilizers for poly(vinyl chloride)

It has been found that modified benzotriazoles: (2-(2-hydroxy-3-chlormethylacetamid-5-methylphenyl)2H-benzotriazole, 2-(2-hydroxy-3[(N,N-di-n-butyl)acetamidmethyl]-5-methyl-phenyl)2H-benzotriazole and 2-(2-hydroxy-3[(N,N-di-n-octyl)acetamidmethyl]-5-methyl-phenyl)2H-benzotriazole) have photostabilizing properties similar to those of Tinuvin P (2-(2-hydroxy-5-methylphenyl)2H-benzotriazole) for the photo-oxidative degradation of PVC under 3665 and 2537 A. The migration rate of stabilizers in a polymer matrix is decreased by introducing long chain groups. The possible mechanism of photosensitization is discussed.     

Lethal Consequences of Simulated Solar Radiation on the Nematode Caenorhabditis elegans in the Presence and Absence of Photosensitizers

Abstract— The partial destruction of the earth's protective ozone layer has raised concerns about the impact of increased UV radiation on the earth's biological systems. In this study, polychromatic light sources were employed to observe the biological responses of the soil nematode Caenorhabditis elegans to simulated solar UV. Using various filter combinations, action spectra were constructed that approximated those generated previously with monochromatic radiation. In both cases, a mutant strain ( rad-3 ) progressively lost its hypersensitivity as shorter wavelengths were filtered out. In addition, both wild type and radiation-sensitive ( rad ) mutants were irradiated with several combinations of filtered light sources in the presence and absence of two exogenous photosensitizers (ethidium bromide and bromodeoxyuridine). Treatment with either of the introduced photosensitizers increased photosensitivity to solar UV. Solar UV also induced a fluence-dependent reduction in fertility in wild-type animals. These experiments extend previous data and substantially expand our understanding of the biological responses of C. elegans to solar radiation.     

废旧高分子材料在回转窑内热解的研究：热解终温对热解产物的影响

以废旧高分子材料—ＰＥ塑料,ＰＶＣ塑料和废轮胎为试验物料,在外热式回转窑内进行了一系列热解试验。考察了热解终温对热解产物的产率及产物特性的影响。随热解终温的提高,热解气体的产率上升而半焦的产率下降;ＰＥ和ＰＶＣ的热解焦油的产率下降,而废轮胎则相反。在试验温度范围内热解气体的平均热值有一最大值;ＰＶＣ在热解过程中Ｃｌ－ＨＣｌ的转化率为５２０％～５６０％;热解终温对焦油的ＣＨ原子比、热值及族分均有一定影响;热解终温对热解半焦的热值、Ｃ和Ｈ残余率以及半焦反应活性也有一定的影响