In this paper, the production of POLYETHYLENE foam CROSSLINKED by gamm irradiation is reported. At first the behavior of POLYETHYLENE against gamma irradiation was studied. Gel-content experiments were performed to investigate the efficiency of two CROSSLINKED promoters, DCP and TMPTA. The results showed that these additives had significant effect in increasing the gel percent at low doses. But their effect was diminished at higher doses. The next phase was to determine the optimum dose and level of crosslinking promoters. To do this, rheometry experiments were performed on both CROSSLINKED and virgin POLYETHYLENE and also the states of foaming of POLYETHYLENE in different gel percents were compared together. In the next stage, compression moulding technique was selected after examining different alternatives such as direct heating in oven or extrusion. Mould temperature and residence time of sample,were determined based on the results of DSC and TGA thermographs. The results showed that increase in blowing agent from 10 to 15 phr leads to cell rupture and an increase in density and thermal conductivity. Therefore, the concentration of 10 phr of blowing agent was reported as the optimum content in which the product had minimum density and thermal conductivity. The SEM micrographs confirmed previous results. Other experiments such as tensile strength and water absorption were also performed on samples and acceptable results proved the quality of the produced foams.

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

Actuators are the controllable work-producing devices with an input of thermal, electrical or magnetizing stimuli and an output of mechanical energy. Regarding their widespread use, smart polymers have recently been used in producing actuators. Smart polymers are a group of neat or composite materials, which have inherent smartness along with self-adaptive capabilities against external stimuli. Shape memory polymers which are also a group of smart polymers, can recover their initial and permanent shape under external stimuli. In this work an actuator was made of a shape memory cross-linked POLYETHYLENE and the effects of different factors such as the content of cross-linking agent, deformation temperature, strain ratio, strain rate, type of cooling and heating rate on final shape recovery, recovery speed and the actuator behavior between 10% and 90% of final recovery were investigated. The results show that the actuator made of cross-linked POLYETHYLENE has a controllable behavior in this range.

Cross linking of high density POLYETHYLENE (HDPE) was performed via high energy electron beam (EB) irradiation. HDPE was also cross linked with dicumyl peroxide (DCP). The gel content of samples was determined by solvent extraction. The degree of cross linking was evaluated by hot set apparatus; also. In order to clarify the effect of the nature of cross linking, correlation of electrical properties such as volume resistivity, dielectric constant, and dielectric strength with the type of cross linking system was derive. It was found that, at identifical amount of gel content, electrical properties of samples prepared by two kinds of cross linking methods, differed significantly.