含铁络合物类光敏剂降解塑料性能的研究

合成了以二硫代氨基甲酸为配体的一系列铁络合物以及硬脂酸铁光敏剂。通过人工加速紫外光降解试验和自然暴露试验,研究了含光敏剂的LDPE膜的力学性能、粘均分子量、红外线吸收及羰基指数的变化,比较讨论含上述铁盐光敏剂的LDPE的光降解性能     

含FeDBC光敏剂的低密度聚乙烯膜紫外光氧化降解的研究

合成了N,N-二正丁基二硫代氨基甲酸铁(FeDBC)光敏剂,通过元素分析、热谱分析、红外(IR)光谱和紫外(UV)光谱表征了它的组成和性质。进而研究了FeDBC对UV光氧化低密度聚乙烯(LDPE)膜的物理性能、羰基指数和粘均分子量的影响,并探讨了FeDBC在敏化LDPE膜光氧降解方面的作用机理。结果表明,在LDPE膜中加入0.1％～0.3％FeDBC,即成可控寿命的LDPE农膜。     

硬脂酸铁加速LDPE膜光降解作用的研究

本文合成了硬脂酸铁(FeSt_s),用等离子体发射光谱、热分析仪、紫外光谱、红外光谱等分析手段进行了表征,研究了它对光氧化低密度聚乙烯(LDPE)薄膜羰基指数和粘均分子量的影响,并探讨了它的作用机理.结果表明:在LDPE膜中加入0.1%～0.3?St_s,即可控制可分解LDPE膜的使用寿命;羧酸铁在光解LDPE膜中的敏化活性依次递减如下:硬脂酸铁>月桂酸铁>辛酸铁;月桂酸铁和辛酸铁的光敏催化活性较低;二苯甲酮不是LDPE的有效光敏剂,能阻滞LDPE的光降解作用;高温下UV光降解LDPE膜的光降解速率高于低温下的光降解速率.     

含淀粉与光敏剂的LDPE膜可控光生物降解

研究了含超淀粉及硬脂酸铁或Ｎ,Ｎ－二正丁基二硫代氨基甲酸铁／Ｎ,Ｎ－二正丁基二硫代氨基甲酸镍光敏剂的低密度聚乙烯膜光氧化降解羰基指数,粘均分子量和真菌侵蚀（级）的变化。结果表明,只需在ＬＤＰＥ膜中添加５％－１５％淀粉和０．１％－０．３％ＦｅＳｔ３或０．０５％－０．２０％ＦｅＤＢＣ／ＮｉＤＢＣ光敏剂,在自然曝露条件下可控ＬＤＰＥ膜的使用寿命 。     

含铁光敏剂在LDPE降解地膜中的应用研究

研究了二烷基二硫代氨基甲酸铁(FeDRC)复合添加剂对LDPE地膜力学性能、羰基指数和粘均分子量的影响。结果表明、含FeDRC复合添加剂的可控光降解LDPE地膜在贮存过程中力学性能稳定,曝露后期光降解效果良好。     

光氧化降解农用地膜的研究

研究了添加光敏剂二丁基二硫代氨基甲酸铁（ＦｅＤＢＣ）、乙酰丙酮铁（ＦｅＡｃＡｃ）、苯并蒽酮（ＢＡＮ）的光氧化农用地膜的降解行为。结果表明，在双组分光敏剂的协同作用下，农用地膜的光氧化降解程度显著增加。     

含碳酸钙与光敏剂的ＬＤＰＥ膜光氧降解研究

研究了含超细碳酸钙（CaCO3)、硬脂酸铁（ＦeSt3)[或二正丁基二硫代氨基甲酸铁(FeBDC)／二正丁基二硫代氨基甲酸镍（NiDBC)光敏剂]的低密度聚乙烯（ＬＤＰＥ）膜的光氧降解碳指数（ＣＩ）和粘均相对分离子质量（Ｍη）的变化。结果表明,在ＬＤＰＥ膜中加入１０％－２０％ＣaCO3和０．１％－０．３％ＦeSt3或０．０５％－０．２０％ＦeDBC/NiDBC,在自然曝露条件下可控制ＬＤＰＥ膜的寿命。     

FeDRC复合添加剂在LDPE地膜中的光降解性能研究

叙述了二烷基二硫氨基甲酸铁(FeDRC)复合添加剂的组成,各组分的协同关系及作用,研究了它对LDPE地膜力学性能,羰基指数和粘均再子量的影响。结果表明,含FeDRC复合添加剂的LDPE地膜在贮存过程中力学性能稳定。曝露前期诱导期明显,曝露后期光降解效果良好。     

不同光敏剂对LLDPE薄膜光降解性能的影响

通过在线型低密度聚乙烯(LLDPE)中分别添加光敏剂硬脂酸铁(FeSt3),二氨基二硫代氨基甲酸铁(FeDBC)和二茂铁((C5H5)2Fe),用母料法制得光降解LLDPE薄膜。采用傅里叶红外变换光谱仪、万能材料试验机和乌氏黏度计分别测定羰基指数、力学性能和分子量,研究了在实验室紫外老化条件下,3种光敏剂及其用量对LLDPE薄膜降解程度的影响。结果表明:3种光敏剂光敏活性为FeSt3>FeDBC>(C5H5)2Fe;通过调节FeDBC或(C5H5)2Fe的添加量可以控制薄膜的降解寿命。     

可控光降解塑料光敏剂的合成及光敏化效果的研究

合成了二乙基二硫代氨甲酸铁（ＦｅＤＥＣ）、二丁基二硫代氨基甲酸铁（ＦｅＤＢＣ）、月桂酸共生稀土、硬脂酸铈和硬脂酸铁５种可控光降解塑料光敏剂。采用人工加速老化实验，户外曝晒试验，ＩＲ、ＵＶ及ＴＧ－ＤＴＡ等方法探讨了它们的光敏化效果及其光敏化作用的机理。     

Study of ultraviolet photooxidative degradation of LDPE film containing cerium carboxylate photosensitizer

The carbonyl indices (CI) of photooxidation of low-density polyethylene (LDPE) films containing cerium carboxylate (CeCar₃) with/without aromatic ketones (AK) were determined by infrared (IR) spectroscopy. The effects of these photosensitizers on the rates of ultraviolet (UV) photooxidation of LDPE films and their mechanism in sensitizing photooxidative degradation are studied. Results show that CeCar₃ can cause the accelerated photooxidative degradation of LDPE films, but CeCar₃ in combination with AK may bring about the accelerated or retarded photooxidative degradation of LDPE films to varying degrees. After UV irradiation, followed by long duration storage, LDPE films containing these photosensitizers continued storage oxidative degradation at the storage oxidative rates similar to the past, except for the Michler ketone.     

Artificial ageing of low density polyethylene film containing chemically bound UV - stabilizer

This paper deals with photostabilization of low density polyethylene films (LDPE) grafted with the UV-stabilizer 2-hydroxy-4-(3-methacryloxy-2-hydroxy-propoxy) benzophenone (HMB). The influence of grafting yield and the other grafting conditions upon photostabilization efficiency of LDPE films were then studied. The chemically bound monomer (HMB) was localized mainly near the surface of an LDPE film. The grafted LDPE film was exposed to an ultraviolet radiation source, and the degree of oxidation and other photooxidative changes were determined by transmission IR and ATR IR spectroscopy. Experimental results show that radiation grafting of a UV-stabilizer upon LDPE films is an efficient photostabilization method.     

Structure–property behavior of polyethylene exposed to different types of radiation

A detailed study was performed on unirradiated low‐ and high‐density polyethylene (LDPE and HDPE) films as well as irradiated films with different types of radiation such as ⁶⁰Co γ rays, thermal and fast neutrons, and electron beam irradiation. The structural changes of PE films were characterized by Fourier transform infrared (FTIR), Fourier transform Raman (FT–Raman), and ultraviolet (UV) spectrometric techniques. The results showed significant radiation degradation, crosslinking, and changes in the crystalline and amorphous regions. The influence of γ‐radiation on the structure of PE was found to be more prominent compared to that of thermal neutrons and electron beam irradiation. However, LDPE film was found to be more sensitive to these types of radiation in accordance with HDPE because of its lesser degree of crystallinity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 179–200, 2000     

LDPE composite films incorporating ceramic powder emitting far‐infrared radiation for advanced food‐packaging applications

A ceramic powder that emits far‐infrared radiation (FIR) was incorporated into low‐density polyethylene (LDPE) via melt‐compounding and subsequent melt‐extrusion processes. To investigate the feasibility of as‐prepared LDPE/FIR composite films for use in packaging applications, the composite films were characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, FIR emissivity and emissive power, antimicrobial activity assays, and storage tests. The physical properties and antimicrobial activities of the composite films were found to strongly correlate with the changes in the chemical and morphological structures that originate from different contents of FIR ceramic powder. A higher content of FIR ceramic powder in the LDPE/FIR composite film provided increased FIR emissivity and emission power of the composite and resulted in good antimicrobial activity. Storage tests also showed that incorporation of FIR ceramic powder into LDPE film was an effective method for maintaining the freshness of lettuce. Furthermore, the incorporation of FIR ceramic powder into LDPE films induced higher thermal stability and crystallinity and enhanced their barrier properties, which suggest these LDPE/FIR composite films are potential candidates for advanced packaging materials for the food and medical industries. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43102.     

Physicochemical properties of irradiated and loaded LDPE films with polyfunctional monomers

Polyfunctional monomers (PFMs), namely, trimethylol propane trimethacrylate (TMPTMA), trimethylol propane triacrylate, ethylene glycol dimethacrylate, and diethylene glycol diacrylate were blended with low‐density polyethylene (LDPE) and exposed to different doses of EB irradiation. Fourier transform infrared and ultraviolet and UV–vis spectroscopy of the unirradiated, irradiated, unloaded, and PFMs‐loaded LDPE films were studied under various irradiation doses up to 300 kGy. The degree of crosslinking and oxidative degradation, as measured by the spectroscopic parameters, were dependent on both the irradiation dose and the type of loaded PFMs. For all of the loaded monomers, the extent of crosslinking increased at different rates as a function of irradiation dose. TMPTMA monomer was the most efficient in enhancing the crosslinking of LDPE films compared to the other loaded monomers. However, the unloaded LDPE film showed the least extent of crosslinking. In addition, the EB‐radiation‐induced changes, such as trans‐vinylene formation, a decrease in vinyl and vinylidene unsaturation; and carbonyl double‐bond formation and change in crystallinity were correlated. The importance of these results on the prediction of the role of polyfunctional monomers in the production of crosslinked polymers is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2025–2035, 2003     

LLDPE/LDPE/TiO2复合膜的分散及光学性能

讨论了纳米TiO2在线型低密度聚乙烯（LLDPE），低密度聚乙烯（LDPE）复合体系中的分散和体系流变行为，研究了复合薄膜的光学性能。结果表明，以高流动性LDPE为基体的纳米TiO2母料，加入LLDPE，LDPE体系中后。复合体系的表观粘度有所提高。但拉伸粘度显著下降。纳米TiO2母料在LLDPE／LDPE复合体系中具有良好的分散性，复合薄膜中的纳米TiO2为一次粒子。纳米TiO2起到了异相成核剂的作用。球晶的粒子得到细化。在本研究的纳米填充范围内（质量分数不大于1.0％），复合薄膜的透光度基本不变。雾度发生了较大幅度上升，复合薄膜在紫外光区域的吸收显著增强。     

Photodegradation of low-density polyethylene with prooxidant and photocatalyst

Low-density polyethylene (LDPE) composite films with trisilver phosphate (Ag₃PO₄) and cadmium selenide (CdSe) particles as photocatalysts and manganese stearate as prooxidant were prepared. The film samples were irradiated under UV and visible light and their photodegradation were evaluated using Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. The carbonyl index of the photocatalyst containing samples was very higher than the pure irradiated LDPE and even prooxidant containing film. The morphologies of the irradiated composite films were completely changed and had many cavities and cracks. The thermal stability of the composites was very lower than the pure polyethylene. However the crystallinity of the LDPE films with photocatalysts was enhanced contrarily the LDPE film with manganese stearate. Generally the results showed that the combination of the prooxidant with photocatalyst have synergistic effect on the photodegradation of the LDPE and can be used to accelerate the degradation of the polyethylene films.     

A New Synthesized of Ferrous Ricinoleate Mixed with Maleic Dextrose Additive to Enhance Photo and Biodegradation Characteristics of LDPE

Low density polyethylene films blended (LDPE) with mixed Ferrous ricinoleate maleic dextrose additive have been exposed to accelerated UV and biotic environments. The films were accelerated UV light for 70 h before being mixed with water and municipal solid compost. The photo degraded and biodegraded LDPE films were examined by infrared spectroscopy and also to study the photodegraded film attacked by mitochondria β oxidation process of microorganism and its morphological study by SEM analysis and degree of crystallinity behaviour by XRD analysis.     

Natural weathering,artificial photo‐oxidation,and thermal aging of low density polyethylene: Grafting of acrylic acid onto aged polyethylene films

The photo‐oxidation and thermal initiation changes of commercial low density polyethylene (LDPE) films used in greenhouse covering, in the presence or absence of ultraviolet (UV) stabilizer, were monitored by infrared (IR) spectroscopy, by mechanical tests and by applying the grafting of acrylic acid onto the aged films. It was found that the resistance of PE films to UV irradiation and heat initiation as proved by tensile strength and elongation at break % was better for stabilized PE films compared with the unstabilized ones. A simple correlation was not observed between the fall in mechanical properties and the rate of film oxidation. On the other hand, an almost linear relation was obviously noticed between the degree of PE oxidation (C?O) measured by IR spectroscopy and the grafting level. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2365–2371, 2003