Study on Irradiation Effect of Structured and Performance Irradiated Crosslinked Polyolefin/NR Thermoplastic Elastomer Foam Materials x Wang Yazhen, Zhang Liye, 2 Duan Jingkuan 3, Du Tao 1 (1 Department of Information Materials Science and Engineering, Guilin University of Electronic Technology, Guangxi, Guilin 2, Beijing School of Life Science and Technology, University of Chemical Technology, Beijing 1000293, China, School of Chemistry and Chemical Engineering, Shanghai Jiaotong University, Shanghai. The test of gel content shows that the degree of crosslinking of the foaming system increases with the irradiation dose. Large irradiation doses (>60ky are not conducive to foaming of radiation crosslinked polyolefin/NR thermoplastic elastomer foams; as the irradiation dose increases, the apparent density and compressive properties of the material increase. SM studies show that: The increase of irradiation dose, the microscopic cell size of the material becomes smaller. DSC research shows that the increase of irradiation dose is beneficial to the improvement of heat resistance of the mixed materials. Fourier infrared spectroscopy (R) studies show that the irradiation dose affects foaming The microstructure of the material, the increase in the irradiation dose, causes degradation reactions inside the material. 2: A article number: 1001 thermoplastic elastomer has similar physical properties to ordinary vulcanizates, exhibits rubber elasticity at normal temperature, and can be plasticized at high temperature. It is a new material between rubber and plastic. In recent years, domestic and foreign scholars have extensively studied the natural rubber polyolefin blend thermoplastic elastomer. The resin part is mainly HOPEEVA and 1DPE121. The thermoplastic elastomer (TPO) has high impact strength, weather resistance, water resistance and electrical properties, and density. Small, flexible processing and low cost, it has been rapidly developed and widely used in electrical and electronic, automotive parts, building sealing, sports equipment, machinery and other fields. At present, its production technology mainly adopts three methods of reactor synthesis, dynamic vulcanization and mechanical blending. 131 However, these methods are complicated and chemically polluted. In recent years, with the advancement of people's environmental awareness, radiation technology has been widely used in the field of polymer materials. At present, extensive research on the use of radiation technology to vulcanize rubber 1451, especially the radiation crosslinking of rubber olefin thermoplastic elastomer has become a research hotspot. The radiation crosslinked thermoplastic elastomer does not need to be added with a crosslinking agent, sulfur and an accelerator, and has no pollution to the environment and high efficiency; and the irradiation is usually carried out at a normal temperature, and the crosslinking occurs in the amorphous region of the rubber and the polyolefin, and the rubber is exchanged. The crystallization zone still exists after the association, so that new properties such as heat resistance and thermal stability are high 61, and environmental pollution due to heating is also reduced. At present, the research on this aspect is mainly based on thermoplastic elastomers blended with synthetic rubber such as polyolefin and EPM neoprene, SBR butadiene rubber, etc., and there are few reports on radiation-vulcanized natural rubber olefin elastomers. In this paper, the radiation cross-linking foaming of LDE/EVA/NR elastomers was studied by radiation crosslinking method, and the effects of irradiation and irradiation on the properties of the materials were studied. The formulation was carried out, and as the gel content increased, the apparent density of the sample increased. This is because the increase in the degree of cross-linking of the system leads to an increase in the number of cross-linking points inside the foam, which increases the melt strength of the mixed material, limits the expansion of the gas inside the material, and leads to an increase in the volume fraction of the rubber and resin inside the foam. Therefore, the apparent density of the foam increases. The relationship between the 222 and the foam cell size is different from that of the crosslinked polyolefin/NR thermoplastic elastomer foamed material. As shown, (a ~ (e cells are continuous, closed-cell honeycomb-like structure; (a cell size is slightly larger than (b) (b is slightly larger than (c) (d) and (e) The cell size is the smallest. The main reason for the difference in cell size is that the irradiation doses of the four foams are different: the irradiation dose from (a to (e) is gradually increased. As mentioned above, the irradiation dose is larger, The higher the gel content of the system, ie the higher the degree of cross-linking, the greater the melt viscosity of the system, which limits the expansion of the bubbles. The pore size of the resulting material is small; however, the degree of cross-linking is too large and the gas in the melt cannot expand uniformly. The cell distribution of the material is not uniform. It indicates that the degree of cross-linking of the system has a great influence on the cell size of the radiation-crosslinked MIDPE/EVA blend foam material under certain conditions of material composition and processing. The effect of the 234 cross-linking degree on the compression set property of the foam is different from the compression set of the radiation-crosslinked polyolefin/NR thermoplastic elastomer foaming material. See Table 2 for the same material. Composition, when the irradiation dose is 50kGy, the elastic recovery rate of the thermoplastic elastomer foam (Ae is greater, the foam has the best resilience performance, followed by 40k7 ​​difference. This can be explained by the cell structure of the foam, When the irradiation dose is 30kGyt, the foam has the largest cell size, so when the external force is compressed, the probability of the cell being collapsed is large. When the external force is released, the cell is difficult to recover. The greater the degree of cross-linking, the foam The better the compression resistance is. Effect of 224 on thermal properties of foamed materials Thermal analysis curves of polyolefin/NR thermoplastic elastomer foamed materials at different irradiation doses, see ~6. As seen from the figure, for the same material composition system, with irradiation dose The increase in the melting point of the thermoplastic elastomer foaming material increases. This is because the increase in the irradiation dose increases the degree of cross-linking of the material, and the density of the cross-linked network structure inside the foam mixing system increases. As the temperature rises, more heat is necessary to overcome the cross-networking. The bondage, resulting in an increase in the melting point of the mixed system. At the same time, this also shows that the increase in the irradiation dose increases the heat resistance of the foam. 23 Influence on the microstructure of the material The effect of cross-linking degree on the microstructure of the radiation-crosslinked polyolefin/NR thermoplastic elastomer foamed material is described. It can be seen from the figure that the most obvious difference between the groups in the five sets of curves in the infrared spectrum is the change in the characteristic peaks at 3342 m-, 1688 ca 1 and 11 m-. These three characteristic peaks are attributed to hydrogen bonds and double bond ether bonds, respectively. The changes of these three characteristic peaks can be analyzed from the reaction mechanism. As the irradiation dose increases, the hydrogen bond characteristic peak gradually strengthens, reflecting the gradual increase of the hydroxyl group on the polymer molecule. This phenomenon reflects that the blend of NREVA and FE exposed to irradiation has a reduced angle solution and the degradation reaction gradually becomes apparent as the irradiation dose increases. The increase in the characteristic peaks of the double bond and the ether bond indicates that a cross-linking reaction has occurred in the PE/EVA/NR blend, indicating that the cross-linking reaction of the blend occurs after irradiation to achieve the purpose of cross-linking. It is indicated that in the process of irradiation cross-linking, accompanied by the falling angle solution of the material, the irradiation dose should be strictly controlled during the experiment. The DSC curve of the material of different radiation doses (upper page 82) is not as good as the BASF product. The reason may be that the crystal molecular integrity of the pigment is not as good as that of BASF, and the development of the crystallization process is promoted by improving the post-treatment process. Should improve product quality and performance. 3 Conclusion Through the above discussion, we can draw the following conclusions: It has reached the level of similar foreign products; and the domestic PB5:1 pigment has a certain gap in color performance with BASF. Domestic pigments have similar performance in terms of dispersing properties and processing properties compared with similar foreign products. Domestic pigments are comparable in heat resistance to foreign products, and the heat resistance of China 3 pigments needs to be improved. From the experimental results, the four indicators of color performance, dispersion performance, processing rheological properties and heat resistance basically reflect the degree of crosslinking of the main 3 conclusions of the pigment. As the irradiation dose increases, the gel content of the system increases, that is, the degree of crosslinking increases. The foaming properties, mechanical properties, cell morphology and microstructure of the material have a great influence. As the degree of crosslinking increases, the apparent density of the article increases, the size of the microscopic morphology of the cell decreases, the compressive resilience of the material increases, and the heat resistance is improved. From the microstructure of the material, the increase in the degree of crosslinking is accompanied by the crosslinking and degradation of the PE/EVA/NR material. (Finish) Positive Yarn Feeder,Yarn Feeder For Crocheting,Positive Yarn Feeders,Positive Yarn Feeding Device Changzhou Longfu Knitting Co., Ltd. , https://www.nbcircularmachine.com