Papers by Keyword: Polyethylene (PE)

Abstract: In this paper, ultrahigh molecular weight polyethylene (UHMWPE) superfine fiber was fabricated by flash-spinning method using UHMWPE as the fiber-forming polymer, 1, 2-dichloroethane as the main solvent. Use central composite design principle, the four factors which mainly influenced the properties of the fiber: spinning temperature, spinning pressure, spinning solution concentration，room temperature were designed for the experiments on the basis of single factor experiment. It can be seen from the results that the predict value are very close to the actual value, the sequence that the factor impact on the overall property of the fiber is: spinning solution concentration>spinning temperature>spinning pressure>room temperature. The optimum condition obtained is: spinning temperature is 196.6 °C, spinning pressure is 12.7MPa, spinning solution concentration is 6.3%, at room temperature 15.1 °C, and the overall property of the fiber was 92.9 under these conditions. Spinning fiber under the optimum condition use 5L autoclave, and the overall performance of the fiber had an average of 91.2. So it is feasible that using this method to optimized the flash spinning process.

Abstract: Low density polyethylene and linear low density polyethylene (LDPE/LLDPE (60wt.%/40wt.%))as basic materials, intumescent flame retardant ammonium polyphosphate (APP) was added into them to obtain fire retardant systems. The molding parameters, fire retardant properties, mechanical properties and processing properties of samples were examined. It was showed the rotational speed of main screw was 28-34rad/min. when samples were molded, cylinder temperature was 185-195°C, mold temperature was 85-115°C, preheating time was 5-10min and filling time was 8-21s. APP had good fire retardant and smoking suppression functions. Adding 30% (wt.%) APP can obtain grade of FV-0. With APP content increasing, the mechanical and processing properties of materials decreased.

Abstract: Linear low density polyethylene (LLDPE) was chemically modified with grafting maleic anhydride (MAH) monomer on its backbone by melting blending. Nano-particles SiO2 was modified by cationic surfactant hexadecyl trimethyl ammonium bromide (CTAB) and anionic surfactant sulfosalicylic acid (SSA) and added to PE coating respectively. Measurement of membrane potential showed that the coating containing modified SiO2 nano-particles had characteristic of ion selectivity. The properties of the different coatings were investigated according to relative industrial standards. Experimental results indicated that PE coating with ion selectivity had better performances, such as adhesion strength, cathodic disbonding and anti-corrosion, than those of coating without ion selectivity. Crystal structure of the coatings before and after alkali corrosion was characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). Structure of the coating without ion selectivity was damaged by NaOH alkali solution, causing mechanical properties being decreased. And the structure of the ion selective coatings was not affected.

Abstract: After entering the soil, the degradation products of polyethylene film have a series of influences on ecological environment of the soil. The influences of the molecular weight and the cumulative amount of degraded polyethylene, soil type and soil depth burying polyethylene on the concentration of CO₂ in the soil were investigated through the orthogonal test L₉(3⁴) . Collection and testing of CO₂ were conducted by gas collector underground and the infrared detector of the Automatic Monitoring System of Soil. The change of CO₂ in the soil at a growth cycle of maize was detected continuously by online monitor. The experimental data was analyzed using DPS data processing system. The results show that the impact of soil depth burying polyethylene on CO₂ concentration increase with the increase of burying time, and the molecular weight of polyethylene has a decreasing impact on CO₂ concentration with the increase of burying time. In the former period of the maize growth, the CO₂ concentration is higher in the clay than in the sand and loam. But in the later growth stage the CO₂ concentration in the loam are more abundant than other two soils.

Abstract: In order to resolve the soil polluted problem which were brought by polyethylene, the study focus on the effects of different molecular weight polyethylene powders to soil, and discuss the molecular weight change of polyethylene. This study made use of four kinds of molecular weight polyethylene powders as materials, added them into the soil of potted soybean to test efficient N content, efficient P content, efficient K content in every development period of soybean, and test the molecular weight of four kinds of polyethylene after the whole development periods of soybean. The Important findings in this study were that there are no significant differences among the efficient N content, efficient P content, efficient K of control group and every experimental group, the molecular weight of polyethylene are nearly no change. it means that the different molecular weight polyethylene powders have no effect to soil.

Abstract: A simple injection molding process was proposed for manufacturing polyethylene (PE) biofilm carrier composited with various powder additives including hydroxyapatite (HAP), starch, bagasse, activated carbon(AC) and magnetic powder(MP) as slow-released nutrients in wastewater biological treatment. The powders were also responsible for improving the hydrophilicity and biomass affinity of the carrier. Pre-attachment between powders and PE particle may achieve great improvement in flow ability of particle-powder mixture during injection molding process. The slow release rate of nutrients (mainly water-soluble starch) from the modified carrier to wastewater can be controlled by the amount of bagasse and activated carbon supplemented in the carrier. The contact angle of a water droplet on the polyethylene surface decreased from 80° to 59° after modification, and the period of biofilm formation on the modified carrier with acclimated sludge reduced from 7 days (on PE carrier without additives) to 4 days. The amount of attached biomass on the modified carrier was also found about twice as that on the common PE carrier. The strength performance test demonstrated the capability of long-term operation for the modified carrier in practical application.

Abstract: Electrofusion joint is used widely for PE pipes; the quality of the joint influences the safety of gas distribution system. Proven and reliable NDT technology of the joint is immature. The attenuation of ultrasound in PE is higher than for metals. Defects Include voids, cracks, bad fusion interfaces, dislocations of heating wires, could find be ultrasonic phased array testing. Examination time, surface of specimen, transducer, calibration block, resolution, examination range and couplant are recommend.

Abstract: Calcium carbonate (CaCO3) is one of the most useful and versatile materials known to man. In this research, eggshell as a natural composite bioceramics was used to modify and improve the mechanical properties of an existing polyethylene which is widely used to manufacture daily goods by small medium industries in Malaysia. Chicken eggshell containing 95% Calcium Carbonate is highly potential to be used as bio-filler to improve poly-based matrix in improving their performance behavior. PE was chosen for this project to modify its virgin mechanical properties by reinforcing eggshell/calcium carbonate and later investigate its character to improve the current product’s performance. Tensile, creep and flexural tests were carried out to characterize the developed PE-CaCO3 composites. Eggshells which were prepared into hundreds of microns and furnace dried at 90oC continuously for eight hours to improve the bonding capability. They were then particulated into polyethylene matrix accordingly as per the designed weight ratios, 10%, 20%, 30% and 40%. From the result, it was learnt that the ES filler has improved mechanical properties of virgin PE as far as 5% to 9% depending on the filler weight ratio. Therefore, ES which was a burden for disposal and being environmental threat can now be used for the betterment of PE product performance.

Abstract: A kind of hyper-dispersant(MA) was synthesized as compatibilizer between PE/OMMT composite. when the weight ratio of PE/OMMT/MA was 100:2:0.5,the composites had outstanding machine performances. SEM micrograph indicated that the PE/OMMT/MA composites mixed uniformly compared to PE/OMMT composites, and TEM test showed that PE had entered into layers of montmorillonite to form intercalated composites.

Abstract: Nanocomposite made of clay minerals and polyolefin goes through several steps. During these steps materials will have changes especially in the structure and properties. Then the final material will be of both new structure and properties. These main steps in the manufacturing process will include the stages of preparation of the material components and mixing. The structures of the materials are well characterized at each step. Then, we can understand how the processing steps will affect the structures and mechanism for producing the final nanocomposite material. The results include characterization by SEM, TEM, XRD and EDAX chemical analysis. During the processing, the energy will be changed for both of the initial materials and the final product in addition to the materials properties which will depend on the energy changes. The analysis includes the methods of calculations of energy changes. Then, design suggestions are developed for energy control to produce nanocomposite with certain energy level to carry certain amount of loads. Therefore, the study will provide possibility for pre-control of the lifetime of the produced materials.