Comparative study on the effects of galbanic acid, galbanic ferric salt and tetrabromo galbanic acid on photo-oxidative degradation of linear low density (LLDPE) films

e-Polymers ◽  
2012 ◽  
Vol 12 (1) ◽  
Author(s):  
Marjan Shahmir ◽  
Homa Asempour
Keyword(s):  
Oxidation Rate ◽  
Degradation Rate ◽  
Catalytic Effect ◽  
Oxidative Degradation ◽  
Optimum Concentration ◽  
Elongation At Break ◽  
Photo Oxidation ◽  
Ferric Salt ◽  
Galbanic Acid ◽  
Additive Molecule

AbstractGalbanic acid (GA) is known as an effective photo-sensitizing agent in polyethylene. This paper reports the comparative studies on photo-oxidative degradation of LLDPE films in the presence of varying amounts of galbanic ferric salt (Fe-GA), tetrabromo galbanic acid (Br-GA), GA at the optimum concentration of 0.2% (w/w) and the pure polymer film, exposed to Ultra-Vitalux sun lamp. The degradation rate was monitored through the changes in mechanical properties (retained elongation at break and retained tensile strength) and also carbonyl index. The results obtained revealed that Fe-GA efficiency in enhancing oxidation rate of polymer upon UV exposure is remarkably much more than of GA. In contrast, Br-GA is responsible for initiating photo-oxidation of the polymer and has negligible effects on the rate of degradation. Based on the results obtained, it was proposed that the photo-activity of GA in the polymer arises from the C=C bond present in the side group attached to aromatic lacton rings of additive molecule, probably through its reaction with singlet oxygen and subsequent generation of hydroperoxide. This mechanism in combination with catalytic effect of iron (III) accounted for the higher effect of Fe-GA in accelerating photo-oxidation rate of the polymer

Study on the effect of galbanic acid on photo-oxidative degradation of linear low density polyethylene (LLDPE) films

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Reza Jahanmardi ◽  
Homa Assempour
Keyword(s):  
Oxidative Degradation ◽  
Low Density Polyethylene ◽  
Coumarin Derivatives ◽  
Linear Low Density Polyethylene ◽  
Prooxidant Activity ◽  
Neat Polymer ◽  
Carbonyl Index ◽  
Photo Oxidation ◽  
Time Periods ◽  
Galbanic Acid

AbstractPhoto-oxidative degradation of LLDPE films (~ 250 μm thick) containing varying amounts of galbanic acid (a type of coumarin derivatives) was investigated by exposing the films to an artificial sunlight (emitted by 300 W OSRAM Ultra- Vitalux lamps) at 40°C for extended time periods. Photo-oxidative degradation of the neat polymer film and the LLDPE films containing benzophenone (an active photo-initiator for PE) and coumarin alone were also studied under similar conditions for comparison. The rate of photo-oxidation was assessed by measuring tensile properties, gel content, carbonyl index, molecular weight and density. It was shown that galbanic acid was highly effective in accelerating photo-oxidation of LLDPE films and an outstanding acceleration of photo-oxidation was observed for the film containing 0.2 wt % of galbanic acid in comparison with the film containing the same amount of benzophenone. However, the film containing coumarin did not exhibit considerable difference in behaviour in photo-oxidation relative to the neat LLDPE film during the exposure time. On the basis of the obtained results, the prooxidant activity of galbanic acid was described in terms of activity of the functional groups existing in the substituted moiety of its molecules.

Photo-Oxidative Degradation of Metallocene Linear Low-Density Polyethylene

2009 ◽  
Vol 610-613 ◽  
pp. 243-247 ◽  
Author(s):  
Fu Chen Bai ◽  
Chun Xiao Zhang ◽  
Xi Yao Zhang ◽  
Jian Liu ◽  
Wei Tian
Keyword(s):  
Oxidative Degradation ◽  
Metallocene Catalyst ◽  
Low Density ◽  
Linear Low Density Polyethylene ◽  
Elongation At Break ◽  
Photo Oxidation ◽  
Chemical Structures ◽  
Natta Catalyst ◽  
Physical And Chemical ◽  
Ziegler Natta Catalyst

Films of linear-low density polyethylenes, made from metallocene catalyst and Ziegler-Natta catalyst , were exposed to accelerate photo-oxidation conditions. The investigations were focused on the changes of the physical and chemical structures and elongation at break occurring in the photo-oxidation process. The results showed that ethylene-hexene m-LLDPE was more favorer to photo-oxidize than ethylene-octene LLDPE. The other two ethylene-ocetene m-LLDPEs were comparable to LLDPE with the same comonomer. The oxidation rate of LDPE is slower than those of all the LLDPEs.

Plasma degradation of Cationic Blue dye with contact glow discharge electrolysis

2010 ◽  
Vol 62 (7) ◽  
pp. 1457-1463 ◽  
Author(s):  
Jin Xing-long ◽  
Wang Xiao-yan ◽  
Wang Qing-feng ◽  
Yue Jun-jie ◽  
Cai Ya-qi
Keyword(s):  
Glow Discharge ◽  
Rate Constants ◽  
Degradation Rate ◽  
Catalytic Effect ◽  
Oxidative Degradation ◽  
Blue Dye ◽  
Experimental Conditions ◽  
Contact Glow Discharge Electrolysis ◽  
Degradation Rates ◽  
Glow Discharge Electrolysis

Contact glow discharge electrolysis (CGDE) of Cationic Blue SD-GTL (CB) was investigated by determining degradation rates and rate constants under different voltages, pH, temperature and initial concentrations. The results indicated that 500 V was the optimum voltage for CGDE of CB under experimental conditions. The effect of pH was not appreciable. Fe2 +  and Fe3 +  had a remarkable catalytic effect on the degradation of CB. The degradation rate was up to 99.7% after 3 minutes CGDE treatment when the concentration of Fe2 +  was 20.0 mg/L. And when the concentration of Fe3 +  was 5.0 mg/L, the degradation rate was only 68.6% after 10 minutes CGDE treatment. The reaction mechanisms were also well illustrated by relative reactions and their rate constants. It had been demonstrated that CB underwent oxidative degradation in CGDE.

The Photo-Oxidation of Polypropylene Monofilaments

1977 ◽  
Vol 47 (6) ◽  
pp. 423-428 ◽  
Author(s):  
A. Garton ◽  
D. J. Carlsson ◽  
P. Z. Sturgeon ◽  
D. M. Wiles
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Uv Irradiation ◽  
Oxidation Product ◽  
Uv Exposure ◽  
Thin Surface Layer ◽  
Elongation At Break ◽  
Photo Oxidation ◽  
Oriented Samples ◽  
Oriented Polypropylene

The elongation-at-break of highly-oriented polypropylene monofilaments is much less affected by photo-oxidation build-up than undrawn or partially-oriented filaments. This appears to result from the very poor lateral cohesion of the fibril bundles in the highly-oriented filament, limiting restructuring and cracking to a thin surface layer. For less-oriented samples photo-oxidation-induced restructuring of the surface layer results in deep cracks that can propagate under stress, greatly embrittling the sample. Areas of filaments cold drawn by, for example, bending or stretching deteriorate very rapidly on uv irradiation as a result of strain-induced chromophore formation, and fracture occurs first at these points. Oxidation-product levels (either hydroperoxide or carbonyl) are shown to be an unreliable index of the extent of deterioration of mechanical properties resulting from uv exposure.

The Oxidative Aging of a Compounded Natural Rubber Vulcanizate

1978 ◽  
Vol 51 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. A. Pett ◽  
R. J. Tabar
Keyword(s):  
Natural Rubber ◽  
Reaction Rate ◽  
Oxidative Degradation ◽  
Accelerated Aging ◽  
Zero Order ◽  
Elongation At Break ◽  
Oxidative Aging ◽  
Zero Order Reaction ◽  
The Impact

Abstract For the type of natural rubber compound used in the impact absorbing bumper system, it has been shown that an apparent zero order reaction rate is valid for the degradation of tensile strength, elongation at break and tear strength during oven aging. The zero order rate applies to aging times beyond an induction period and prior to the onset of hardening. Since the rates follow the Arrhenius equation for rate-temperature dependence, accelerated aging can be readily applied to the prediction of long term changes in properties (within the temperature range of 82–171°C). The magnitude of the activation energy determined from losses in mechanical properties indicates the dominance of oxidative degradation as the mechanism of the losses in properties.

scholarly journals Photodegradation of EDTA and NTA in the UV / H2O2 Process

1995 ◽  
Vol 50 (12) ◽  
pp. 1845-1853 ◽  
Author(s):  
Martin Sörensen ◽  
Fritz H. Frimmel
Keyword(s):  
Hydroxyl Radicals ◽  
Degradation Rate ◽  
Catalytic Effect ◽  
Advanced Oxidation Process ◽  
Strong Increase ◽  
Radical Scavenger ◽  
Photochemical Degradation ◽  
Uv Degradation ◽  
Degradation Rates ◽  
Grade Steel

The influence of H2O2 on the UV degradation of the broadly used aminopolycarboxylates EDTA and NTA in aqueous solution was investigated. The photochemical degradation in the UV /H2O2 process was compared with classical oxidative treatment of potable water. The German drinking water regulation (Trinkwasserverordnung) was the orientation for all experiments. The Advanced Oxidation Process (AOP) turned out to be superior to the classical oxidation processes. The photochemical degradation of EDTA and NTA by UV irradiation could be significantly stimulated in the presence of H2O2. There was a strong increase in the degradation rate and a decrease in the quantum yield of the aminopolycarboxylates. Experiments with butyl chloride as radical scavenger proved the photolytically generated hydroxyl radicals to be responsible for the increase in the degradation rates.The effect of increasing the degradation rate at higher concentrations of H2O2 was limited, because the steady-state concentrations of the hydroxyl radicals as reactive species, did not increase at the same rate as the initial concentration of H2O2.Low amounts of iron dissolved from the high-grade steel photoreactor walls had a significant catalytic effect on the degradation.

Effect of the TiO2 Crystallite Size, TiO2 Polymorph and Test Conditions on the Photo-Oxidation Rate of Aqueous Methylene Blue

2014 ◽  
Vol 58 (2-3) ◽  
pp. 85-102 ◽  
Author(s):  
Wan-Ting Chen ◽  
Andrew Chan ◽  
Vedran Jovic ◽  
Dongxiao Sun-Waterhouse ◽  
Kei-ichiro Murai ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Crystallite Size ◽  
Oxidation Rate ◽  
Photo Oxidation ◽  
Test Conditions

scholarly journals Synthesis and Characterization of Biodegradable Polyester/Polyether WPU As The Environmental Protection Coating

2021 ◽  
Author(s):  
Guangfeng Wu ◽  
Xin Song ◽  
ZhiHui Yang ◽  
Ying Chun Li ◽  
HuiXuan Zhang
Keyword(s):  
Thermal Stability ◽  
Contact Angle ◽  
Water Contact Angle ◽  
Degradation Rate ◽  
Soft Segment ◽  
Buffer Solution ◽  
Water Contact ◽  
Elongation At Break ◽  
Protection Coating

Abstract Polyester diol PCL and PBA, polyether diol PTMG and polycarbonate diol PCDL were used as components of WPU soft segment, respectively. Polyether PTMG-WPU has the worst hydrolytic property and the highest thermal stability. The maximum degradation rate temperature Tmax is 407.8°C, the water contact angle reaches 89.5°. Traditional polyester PCL-WPU shows the strongest hydrolysis performance, the smallest water contact angle, only 71.7°, the water absorption rate of 72 hours at room temperature is as high as 26.7%. However, the thermal stability of PCL-WPU is lower, the soft segment Tg is -52.3°C, and Tmax is only 333.7°C, but the mechanical propertie of which is the best, the tensile strength is 58.3 MPa, and the elongation at break reaches 857.9%. The most important thing is that the structure of polyester PCL-WPU is more easily destroyed by lipase and water molecules. The acidic products produced after hydrolysis will further promote the degradation of polyester. Therefore, compared with other WPUs, PCL -WPU has the best biodegradability and the most obvious degradation effect under the same conditions. The degradation rate of PTMG-WPU after 30 days of degradation in 0.6% lipase PBS buffer solution and soil was only 4.2% and 2.3%, while the highest degradation rate of traditional polyester PCL-WPU reached 41.7% and 32.0%, respectively. In addition, polycarbonate PCDL-WPU has the highest hardness, reaching 95.5 HD. But its other performances are lower than PCl-WPU.

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