聚驱井解堵降解剂的优选及性能评价

以过硫酸胺、高锰酸钾和过氧化氢为解堵降解剂,对聚合物PAM溶液进行降粘性能评价。结果表明,过硫酸铵的降粘效果最好,高锰酸钾次之,过氧化氢最差。从经济上综合考虑,建议油田选用过硫酸铵作为降解剂,配制解堵剂进行解堵工作。     

Aging of packaging films in the marine environment

The present article examines the aging behavior in the marine environment of some representative flexible plastic packaging films including supermarket plastic bags made of low‐density polyethylene (LDPE), polyethylene terephthalate (PET) films, polyamide–polyethylene (PAPE) films and films made of a material under the commercial name Mater‐Bi®. The effect of aging was studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, and tension including creep‐recovery tests. The polyethylene films were not hydrolytically degraded during aging in seawater, and the polyethylene chains did not undergo any substantial chain scission. The PET films after exposure for 8 months in seawater did not suffer any substantial degradation, and the PET chains were plasticized by the absorbed water. After prolonged exposure to seawater (12 months), the PET films started to degrade. The PAPE film underwent extensive chemical and structural changes during aging in seawater as result of plasticization and hydrolysis of the polyamide (PA) component in combination with an eventual loosening of the tie layer. Mater‐Bi® film underwent a severe deterioration during aging in seawater due to the hydrolysis of the starch and polycaprolactone components. All films exhibited a marked degradation of their tensile properties after exposure to accelerating aging conditions under UV radiation. POLYM. ENG. SCI., 59:E432–E441, 2019. © 2019 Society of Plastics Engineers     

Degradation assessment of LDPE multilayer films used as a greenhouse cover: Natural and artificial aging impacts

This article focuses on the assessment and understanding of the mechanism of natural and artificial aging processes of a triple‐layer film made of low‐density polyethylene (LDPE) used as greenhouse cover. The film material contains color dye and ultraviolet–A (UV–A) and infrared (IR) stabilizers and antioxidant. The combined effect of temperature variations and UV–A radiations, of the natural and artificial aging, on the physical properties (free surface energy and yellow color measurements), mechanical behavior (tensile tests), thermal stability (TGA and DSC analysis), and structural stability (FTIR analysis) was investigated. The natural aging was conducted on a greenhouse, located in northern Algeria, over a period of 7 months. However, the artificial aging was performed at four different agricultural greenhouse simulating conditions of temperature and UV–A radiation (namely, at 40°C, 40°C with UV–A, 50°C, and 50°C with UV–A) for periods of aging up to 5486 h (7.6 months). The results revealed that, the maximum loss of the yellow color additives occurs at 2981 h under the natural aging process and at 2440, 1096, 1340, and 121 h under the four artificial aging conditions, respectively. There was an observed increase in the films free surface energy and a significant degradation in the mechanical properties with aging time. This can be correlated with the film material structural changes. The natural aging of the film in North Africa is almost equivalent to artificial aging at 40°C. The concurrent effect of temperature and UV–A radiations induced polymer chains scission leading to faster degradation in the film material and consequently a reduction in its durability and service lifetime. The results show also that the measured parameters are directly related to the limit of use criterion for evaluating the lifespan of agricultural greenhouse LDPE covers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Degradation of low density polyethylene during extrusion. III. Volatile compounds in extruded films creating off‐flavor

This study was aimed at finding a correlation between the experienced off‐flavor in packaged foods and the presence of specific degradation products in PE packaging films. The possibility to trap degradation products by chemical reactions with scavengers, that is, zeolites and maleic anhydride grafted LLDPE, were investigated. This trapping would prevent the degradation products from migrating to the polymer film surface and further into food in contact with the film. This work concludes that off‐flavor in water packed in LDPE‐films depends on extrusion temperature and the content of oxidation products in the polymer film. At lower extrusion temperatures, reactive additives to the LDPE material could control the release of off‐flavor giving components. Adsorbents, such as zeolites, which are able to adsorb degradation products, are effective also at higher extrusion temperatures. The amount of oxidized degradation products in the films correlated well to the perceived off‐flavor in the packed water. The presence of aldehydes and ketones have a clear impact on the off‐flavor. The best correlation between off‐flavor and oxidized components were found for C₇? C₉ ketones, and aldehydes in the range of C₅ to C₈. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 847–858, 2005     

Characterization of surface phenomena: probing early stage degradation of low‐density polyethylene films

Photo‐oxidative degradation of polyethylene triggers significant deterioration in the polymer properties. Much interest is aimed at characterizing and possibly predicting photo‐oxidative damages, at early stages, prior to the occurrence of profound changes in mechanical properties. Herein, we study the degradation of low‐density polyethylene (LDPE) films, focusing on surface deterioration processes. Thin films of various molecular weights are exposed to accelerated weathering while their chemical, mechanical and morphological characteristics are monitored throughout by apparent contact angle (CA) measurements, Fourier‐transform infrared spectroscopy (FTIR), tensile test, and electron microscopy. A significant decrease in the films' CA during degradation is observed. CA is highly sensitive to two simultaneous phenomena with opposing effect: nanoscale surface roughening and composition changes. We found the latter (specifically the evolution of polar groups) to be the dominant parameter affecting the CA behavior. Consequently, simple CA measurements coincide well with conventional FTIR analysis, and are more sensitive to changes occurring at early stages of degradation. The deterioration in the mechanical properties is also characterized and is found to present poor sensitivity and high variability at these early aging stages. Thus, simple CA measurements could potentially be used as a qualitative indicator for evaluating the aging impact on LDPE. POLYM. ENG. SCI., 59:E129–E137, 2019. © 2018 Society of Plastics Engineers     

Manganese stearate initiated photo‐oxidative and thermo‐oxidative degradation of LDPE,LLDPE and their blends

This study is an attempt to investigate the effect of a representative pro‐oxidant (manganese stearate) on the degradation behavior of 70 ± 5 μ thickness films of LDPE, LLDPE and their blends. Films were prepared by film blowing technique in the presence of varying quantities of manganese stearate (0.5–1% w/w) and subsequently subjected to accelerated degradative tests: xenon arc exposure and air‐oven exposure (at 70°C). The physico–chemical changes induced as a result of aging were followed by monitoring the mechanical properties (Tensile strength and Elongation at break), carbonyl index (CI), morphology (SEM), melt flow index (MFI), oxygen content (Elemental analysis), and DSC crystallinity. The results indicate that the degradative effect of pro‐oxidant is more pronounced in LDPE than LLDPE and blends, due to the presence of larger number of weak branches in the former. The degradation was also found to be proportional to the concentration of the pro‐oxidant. Flynn‐Wall‐Ozawa iso‐conversion technique was used to determine the kinetic parameters of degradation, which were used to determine the effect of the pro‐oxidant on the theoretical lifetime of the polymer. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Physicomechanical,optical, barrier,and wide angle X‐ray scattering studies of filled low density polyethylene films

Series of low density polyethylene (LDPE) films filled with different fillers such as silica, mica, soya protein isolate, potassium permanganate, and alumina were processed using a single screw extruder. The filled LDPE films were characterized for physicomechanical properties like tensile strength, percentage elongation at break, and tear strength, optical properties like percent transmission and haze. The barrier properties such as water vapor transmission rate and oxygen transmission rate of the filled LDPE films have also been reported. Microcrystalline parameters such as crystal size (〈N〉) and lattice distortion (g) of the filled LDPE films obtained using wide angle X‐Ray scattering method have been reported. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2781–2789, 2006     

Surface modification of LDPE film by chemical processes with Ni2+ and ammonium persulfate

Chemical modification of the surface of low-density polyethylene (LDPE) film was performed with an aqueous solution of ammoniacal ammonium persulfate in the presence of Ni²⁺ ions, where the polar groups were generated on the surface of the LDPE film. The surface of the LDPE film was modified chemically with an ammoniacal solution of ammonium persulfate (1.1M) and Ni(SO₄)₂ (0.02M) heated at about 70°C for 3 h. The morphologies of the surfaces were studied with scanning electron microscopy and infrared spectroscopy; electron spectroscopy for chemical analysis revealed the introduction of polar groups on the surface, which improved printability and adhesion properties. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 406–415, 2001     

Structure–property relationships of composite films

Coextruded multifilms of varying chemical composition and structure were studied by the dynamic mechanical technique. The films studied were two- and three-ply combinations of a polyimide (Kapton) and fluorinated ethylene–propylene copolymer (FEP) and four other two-ply polyethylene and modified polyethylene composites: low-density polyethylene (LDPE)–ionomer, rubber-modified high-density polyethylene (HDPE)–ionomer; ethylene–vinyl acetate (EVA) copolymer–LDPE, and EVA-modified HDPE–LDPE. The mechanical spectra of individual film components were also obtained at 110 Hz between ?120° and 120°C (220°C for the Kapton–FEP system). Mechanical relaxations were examined to determine the degree of interaction between adjacent films and correlate them with tensile and ultimate properties of the composite.     

Degradation of low density polyethylene during extrusion. IV. Off‐flavor compounds in extruded films of stabilized LDPE

This study was aimed at finding a correlation between the experienced off‐flavor in packed foods and the presence of specific degradation products in LDPE packaging films. The possibility to trap degradation products by chemical reactions with scavengers, i.e., a zeolite additive or antioxidants, was investigated This would prevent degradation products from migrating to the polymer film surface and further into food in contact with the film. It was found that off‐flavor noted in water packed in LDPE films depended on extrusion temperature and exposure time for the melt to oxygen, that is, the parameters that influence the contents of oxidation products that are able to migrate from the polymer film. It was also found that adsorption of oxidative degradation products in a zeolite additive or protection of LDPE by using antioxidants could prevent off‐flavor in the packed product (water). However, the antioxidant should be selected with regard to extrusion temperature because thermal instability in the additive might jeopardize the intended effect. Multifunctional antioxidants seem to provide improved protection, the most effective one evaluated in this work being Irganox E201, i.e., vitamin E. Concentrations of oxidized degradation products are well correlated to the perceived off‐flavor in the packed water. The highest correlation between off‐flavor and oxidized components was found for ketones in the range of C₇ to C₉ and aldehydes in the range of C₆ to C₉. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 583–595, 2005     

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     

Use of silica from rice husk ash as an antiblocking agent in low‐density polyethylene film

In packaging applications, blocking is always found in low‐density polyethylene (LDPE) films. Practically, such problems can be solved by incorporation of antiblocking agents, for example, silica and talc. The objective of this research was to explore the possibility of using silica from rice husk ash (RHA silica) as an antiblocking agent in LDPE film. Properties of RHA silica were compared with commercial silica, Sylo‐1. The appropriate amount of silica to be used as an antiblocking agent in LDPE film was also investigated. The results indicate that RHA silica has a smaller particle size and a higher specific surface area but a higher bulk density than those of Sylo‐1 silica. In the plastic film industry, 500–1000 ppm of silica is added in LDPE films as an antiblocking agent. It was also found that LDPE film with 2000–3000 ppm RHA silica showed similar properties to LDPE film filled with commercial silica in terms of its blocking behavior, mechanical strength, and film clarity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 848–852, 2003     

Effect of pro‐oxidants on biodegradation of polyethylene (LDPE) by indigenous fungal isolate,Aspergillus oryzae

Proxidant additives represent a promising solution to the problem of the environment contamination with polyethylene film litter. Pro‐oxidants accelerate photo‐ and thermo‐oxidation and consequent polymer chain cleavage rendering the product apparently more susceptible to biodegradation. In the present study, fungal strain, Aspergillus oryzae isolated from HDPE film (buried in soil for 3 months) utilized abiotically treated polyethylene (LDPE) as a sole carbon source and degraded it. Treatment with pro‐oxidant, manganese stearate followed by UV irradiation and incubation with A. oryzae resulted in maximum decrease in percentage of elongation and tensile strength by 62 and 51%, respectively, compared with other pro‐oxidant treated LDPE films which showed 45% (titanium stearate), 40% (iron stearate), and 39% (cobalt stearate) decrease in tensile strength. Fourier transform infrared (FTIR) analysis of proxidant treated LDPE films revealed generation of more number of carbonyl and carboxylic groups (1630–1840 cm⁻¹ and 1220–1340 cm⁻¹) compared with UV treated film. When these films were incubated with A. oryzae for 3 months complete degradation of carbonyl and carboxylic groups was achieved. Scanning electron microscopy of untreated and treated LDPE films also revealed that polymer has undergone degradation after abiotic and biotic treatments. This concludes proxidant treatment before UV irradiation accelerated photo‐oxidation of LDPE, caused functional groups to be generated in the polyethylene film and this resulted in biodegradation due to the consumption of carbonyl and carboxylic groups by A. oryzae which was evident by reduction in carbonyl peaks. Among the pro‐oxidants, manganese stearate treatment caused maximum degradation of polyethylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface modification of low‐density polyethylene (LDPE) film and improvement of adhesion between evaporated copper metal film and LDPE

To improve the interfacial adhesion between evaporated copper film and low‐density polyethylene (LDPE) film, the surface of LDPE films was modified by treating with chromic acid [K₂Cr₂O₇/H₂O/H₂SO₄ (4.4/7.1/88.5)]/oxygen plasma. Chromic‐acid‐etched LDPE was exposed to oxygen plasma to achieve a higher content of polar groups on the LDPE surface. We investigated the effect of the treatment time of chromic acid in the range of 1–60 min at 70°C and oxygen plasma in the range of 30–90 sec on the extent of polar groups created on the LDPE. We also investigated the surface topography of and water contact angle on the LDPE film surface, mechanical properties of the LDPE film, and adhesion strength of the evaporated copper metal film to the LDPE film surface. IR and electron spectroscopy for chemical analysis revealed the introduction of polar groups on the modified LDPE film surface, which exhibited an improved contact angle and copper/LDPE adhesion. The number of polar groups and the surface roughness increased with increasing treatment time of chromic acid/plasma. Water contact angle significantly decreased with increasing treatment time of chromic acid/plasma. Combination treatment of oxygen plasma with chromic acid drastically decreased the contact angle. When the treatment times of chromic acid and oxygen plasma were greater than 10 min and 30 sec, respectively, the contact angle was below 20°. With an increasing treatment time of chromic acid, the tensile strength of the LDPE film decreased, and the film color changed after about 10 min and then became blackened after 30 min. With the scratch test, the adhesion between copper and LDPE was found to increase with an increasing treatment time of chromic acid/oxygen plasma. From these results, we found that the optimum treatment times with chromic acid and oxygen plasma were near 30 min and 30 sec, respectively. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1677–1690, 2001     

Thermal and microwave‐assisted oxidative degradation of poly(ethylene oxide)

The kinetics of the thermal and microwave‐assisted oxidative degradation of poly(ethylene oxide) were determined with potassium persulfate as the oxidizing agent. Gel permeation chromatography was used to determine the variation of the molecular weight with time. The degradation was studied as a function of the temperature and persulfate concentration, and it was found that the degradation rate increased with the temperature and concentration of persulfate. Continuous distribution kinetics were used to determine the rate coefficients for the degradation process, and the activation energies were obtained. The results indicated that the microwave‐assisted process had a lower activation energy of 10.3 kcal/mol, whereas that of the thermal degradation was 25.2 kcal/mol. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 2090–2096, 2005     

Surface photografting polymerization of vinyl acetate,maleic anhydride,and their charge‐transfer complex. IV. Maleic anhydride

In general, it has been accepted that maleic anhydride (MAH) cannot be homopolymerized under normal conditions. However, MAH can be grafted onto substrates under UV irradiation rather easily. In this study, the photografting polymerization of MAH was examined with low‐density polyethylene (LDPE) film as a substrate. The initiating performances of different photoinitiators, including benzophenone (BP), Irgacure 651, and benzoyl peroxide (BPO), were examined. The effects of some principal factors, such as the temperature, solvent, and UV intensity, on the grafting polymerization of MAH were also investigated. The results show that MAH can be smoothly grafted onto LDPE film by UV radiation. Enhancing the intensity of UV radiation and elevating the irradiation temperature facilitate the grafting polymerization of MAH. Among BP, Irgacure 651, and BPO, Irgacure 651 can initiate the polymerization of more MAH, but BP is more effective for the initiation of surface grafting polymerization. Solvents of MAH also have a great influence on the grafting polymerization; some of them even seem to take part in the reaction. The occurrence of photografting polymerization was verified with Fourier transform infrared and electron spectroscopy for chemical analysis spectra. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 87: 2318–2325, 2003     

Optimization of adhesive joints of low density polyethylene (LDPE) composite laminates with polyolefin foam using corona discharge plasma

In this work, surface modification of low density polyethylene (LDPE) film has been carried out to optimize adhesive joints with polyolefin foam for uses in technological applications. LDPE films were modified in a continuous way using corona discharge plasma with different powers, ranging from 200 to 600 W and several film advance rates in the 5–20 m min^?1 range. Changes in surface wettability have been studied with contact angle measurements and subsequent solid surface energy calculation. A polyurethane adhesive was used to join the LDPE film to a polyethylene foam. Mechanical performance of the adhesive joints has been determined by T‐peel tests and also the aging effects of several hydrothermal conditions have been studied to evaluate the usefulness of these laminate composites in technological applications. Results show that corona discharge powers between 400 and 600 W are suitable in terms of wettability improvement; on other hand, a slight decrease in surface wettability as the film advance rate increases is detected but the overall changes as a consequence of the film advance rate in the 5–20 m min^?1 range are small if compared to changes derived from working powers in the 200–600 W range. Adhesive joints offer excellent mechanical performance and good durability in hydrothermal conditions thus being appropriate for technical applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Photoactive nanocoating for controlling microbial proliferation on polymeric surfaces

A novel antimicrobial polymeric surface coating involving photo-activated generation of the well-known microbiocidal agent hydrogen peroxide was investigated. Modified poly(ethylene imine) (PEI) polymers were prepared containing anthraquinone (AQ) moieties attached covalently to the amino functional groups of the PEI chains. These AQ-modified PEI polymers were applied from solution to the surface of corona-treated low-density polyethylene (LDPE) films. Photoreduction of the PEI-bound anthraquinone derivatives occurred on exposure to low energy UV light, resulting in efficient production of hydrogen peroxide from the coated film on exposure to air.     

Interpenetrating polymer networks based on polyol modified castor oil polyurethane and poly(2‐ethoxyethyl methacrylate): Synthesis,chemical, mechanical,thermal properties,and morphology

Interpenetrating polymer networks (IPNs) of glycerol modified castor oil polyurethane (GC‐PU) and poly(2‐ethoxyethyl methacrylate) poly(2‐EOEMA) were synthesized using benzoyl peroxide as initiator and ethylene glycol dimethacrylate (EGDM) as crosslinker. GC‐PU/poly (2‐EOEMA) interpenetrating polymer networks were obtained by transfer molding. The novel GC‐PU/poly (2‐EOEMA) IPNs are found to be tough films. These IPNs are characterized in terms of their resistance to chemical reagents thermal behavior (DSC, TGA) and mechanical behavior, including tensile strength, Young's modulus, shore A hardness, and elongation. The morphological behavior was studied by scanning electron microscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1029–1034, 2004     

反相乳液聚合法制备P（AA-AMPS）高吸水树脂的合成及其性能结构研究

文章以2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、丙烯酸（从）为共聚功能单体,过硫酸钾（KPS）,过氧化苯甲酰（BPO）为引发剂,聚乙二醇双丙烯酸酯（PEGDA）（Mw=700）为交联剂,以Span-60,Triton X-100为复配乳化剂,通过反相乳液聚合法制备两性离子型高吸水树脂,研究了SAP的合成条件,详细探讨了聚合过程中各种因素对SAP性能的影响,SAP结构与性能的关系等.