Producers and consumers of patch crops notice to more supply with an favonible quality of this crops to market, recently. there for, it is necessary to find appropriate ways of producing plants with a high quality degree for supplying more revenue for producers and responding consumer demands. In current survey, the economic influence of Polyethylene mulches application as a new technology on cucumber cultivation has analyzed then, a survey research with simple random sampling of cucumber producers in Isfahan province as survey society was used for this subject. Price information of degree of cucumber were collected from Isfahan vegetable and fruit organization in harvest period. In order to determination of these mulches effect on yield, an experiment split plot design used in four blocks r with superdaminous cucumber hybrids in Kaboutar-Abad station during 2000-2001. main factors were soil cover in three levels including block Polyethylene mulch(BPM), transparent Polyethylene mulch(TPM) and no Polyethylene mulch(NPM). sub plots were sowing methods in two levels involve of unilateral plots(UP) and bilateral plots(BP). The information of first and second degrees of fruit yield in above factors was registered. according to economic analysis, the priority of treatments were:1- tpm in bp 4- npm in bp2- tpm in up 5- bpm in up3- bpm in bp 6- npm in up

Polyethylene terephthalate (PET), one of the thermoplastic polymers, is encountered with arduous problems in its recycling. After recycling, its mechanical properties drop dramatically and therefore it cannot be used to produce the products as virgin PET does. Polyethylene is a thermoplastic polymer which can be easily recycled using the conventional recycling processes. The decreased mechanical properties of virgin Polyethylene due to the environmental factors can be improved by reinforcing fillers. In this paper, we studied the effects of adding recycled Polyethylene terephthalate (rPET) as a filler, in various amounts with different sizes, on the physical and mechanical properties of recycled Polyethylene. Composite samples were prepared using an internal mixer at temperature 185oC, well below rPET melting point (250oC), and characterized by their mechanical properties. To improve the compatibility between different components, PE grafted with maleic anhydride was added as a coupling agent in all the compositions under study. The mechanical properties of the prepared samples were performed using the tensile strength, impact strength, surface hardness and melt flow index (MFI) tests. To check the dispersity of the Polyethylene terephthalate powder in the Polyethylene matrix, light microscopy was used. The results showed that the addition of rPET improved the tensile energy, tensile modulus and surface hardness of the composites while reduced the melt flow index, elongation-at-yield, tensile strength and fracture energy of impact test. We could conclude that with increasing rPET percentage in the recycled Polyethylene matrix, the composite became brittle, in other words it decreased the plastic behavior of recycled Polyethylene. Decreasing particle size led to higher surface contacts, increased the mechanical properties and made the composite more brittle. The light microscopy micrographs of the samples showed a good distribution of small rPET particles in the Polyethylene matrix.

Background and Aim: Over there past few years, the use of fiber reinforced composites has increased in dentistry. The type of fiber used for reinforcement plays an important role in the structural strength of composites. This in vitro study compares the fracture resistance of posterior reinforced composite inlay bridges with two different fiber types.Materials & Methods: This experimental, in vitro study was performed on 20 FRC bridges which replaced maxillary second premolars. The abutment teeth were prepared with proximal box design and the samples were divided in to two groups of 10 (n=10). For the first group Polyethylene fiber reinforced composites (Fiber span/ NSI/ Australia) were used directly. In second group pre impregnated glass fiber (INTERLIG/ Angelus/ Brazil) were applied the same. After thermo cycling process (5000 cycles, 5°c / 55°c, dwell time 30s, interval 2s) fracture testing was performed in a universal testing machine (Zwick/ Roell/ Germany, 1 mm/ min) applying direct vertical force to the center of the pontic. The One Sample Kolmogorov Smirnov Test showed a normal distribution. Data analysis was done using independent sample T-test.Results: The mean fracture strength and the standard deviation of the FRC Inlay Bridge was 469 ± 247 N for Polyethylene fiber group and 541 ± 206 N for glass fiber group. The result of Independent Sample Test was not statistically significant (P=0.491). The most failure mode observed, was crack and fracture on the surface of FPDs in distal part of the pontics. Frameworks remained with no damage in all samples. There was no stateside difference between two groups of FPDs.Conclusion: Direct application of each fiber reinforced composite (glass or Polyethylene fiber) with the same architecture (Braided) of fibers is comparable in posterior region of maxilla so the structural design of the fiber is more important than the fiber type itself, in fracture resistance of FPDs.

High-density Polyethylene (HDPE)/linear low-density Polyethylene (LLDPE) blends have been designed by varying the HDPE: LLDPE ratio. The ratio of 70: 30 showed the best combination of tensile properties (19. 53 MPa), melt flow index (MFI) (1. 75 g/10 min) and hardness properties (Shore D 46. 5), and its tensile strength and hardness was greater than those of plain LLDPE, whereas its MFI was greater than that of a plain HDPE. Hence, with the same composition, the composites were made by addition of silica with a ratio of 10–, 40%. Incorporation of silica acts as a reinforcement into the system and improves the structural rigidity and 30% incorporation showed the best performance in terms of tensile (23. 69 MPa), and hardness (Shore D 48) but slightly less MFI (0. 85 g/10 min) of the composites. Incorporating coconut shell charcoal (CSC) not only improves the system’, s performance but also utilizes its waste and properties are measured as tensile strength (22. 33 MPa), maintaining the hardness properties and slight reduction in MFI (0. 77 g/10 min). All blends and composites were processed through extrusion and palletization followed by compression molding. Plain silica, CSC as well as the selected blends and composites were evaluated by FTIR, XRD, and SEM analyses. Hence, the synergistic effect of silica and CSC in the HDPE-LLDPE blend is studied and such a composite can be suitable in automotive applications.

In the present study, the thermal oxidation behaviour of high-density Polyethylene (HDPE) containing each of two types of oxidized Polyethylene (OPE), one prepared using 500 ppm of iron (III) stearate as pro-oxidant and the other without the pro-oxidant, was investigated. Fourier-transform infrared spectroscopy (FTIR) showed that the carbonyl index of the HDPE increased from 1.03 to 6.37 upon the addition of 5.0 wt.% of OPE containing the pro-oxidant after 100 h of thermo-oxidative aging at 90°C. Moreover, it was observed that the rate of changes in retained tensile strength and retained elongation-at-break of the HDPE during the thermal oxidation increased in the presence of 5.0 wt.% of each type of OPE, especially, the one containing iron (III) stearate, which was consistent with the obtained data from gel content measurements. Lastly, the evolution in crystallinity of the film samples was monitored by density measurements as well as differential scanning calorimetry (DSC). It was revealed that the crystallinity of the tested films during thermo-oxidative degradation grows faster in the presence of OPE. Overall, the findings indicated that the utilization of OPE containing trace amounts of iron (III) stearate can accelerate the thermal oxidation of HDPE films and facilitate entering the final biodegradation stage, while resolving the need to use high concentrations of harmful heavy metal salts.

Monolithic aerogels of high molecular weight Polyethylene (Mw=3×106- 6×106 g/mol) have been prepared by solvent extraction with supercritical carbon dioxide from thermoreversible gels prepared in decalin. These low density and highly porous aerogels present an apparent porosity up to 90%. The aerogel morphology observed by scanning electron microscopy (SEM) is characterized by spherulitic structures being interconnected by fibers. The X-ray diffraction experiments show that PE aerogels are highly crystalline with a degree of crystallinity of c.a.80% and PE chains being packed into the typical orthorombic unit cell. The combined SEM and N2 sorption investigations show that PE aerogels are essentially macroporous with a small amount of mesopores. The oil-sorption performance of Polyethylene aerogels has been also evaluated in this study in order to assess a possible use of these materials for oil spillage recovery and results show that aerogel macropores allow a very fast sorption kinetics with a 100% oil weight uptake obtained in less than 1 min.

Effect of the blends of different Polyethylenes (LDPE=low-density Polyethylene, LLDPE=linear low density Polyethylene and HDPE=high density Polyethylene) and rubbers (PBR= polybutadine rubber, SBR=styrene butadiene random copolymer, NR=natural rubber and SEBS=styrene-ethylene-butylene-styrene block copolymer) on bitumen properties was investigated. PBR-PE blends form a physical network in bitumen medium, whereas their SBR, NR and SEBS counterparts do not. The properties of the resulting bituminous blends are comparable with those of SEBS blends. LLDPE shows a higher rate of effectiveness on bitumen properties as compared with other Polyethylenes. SBR blends show a better elastic recovery and film forming properties. Addition of heavy vacuum slops (HVS) oil into the ternary blends of rubber-PE-Bitumen results in rubber inclusions volumes. The rubber swelling increases as HVS oil concentration increases. HVS oil concentration could be adjusted depending on the designed performance grade (PG). SBR-PE blends found to be the most effective blends on bitumen properties.