| Dynamic vulcanized ethylene-propylene-diene monomer(EPDM)/ polypropylene(PP)thermoplastic elastomer is called EPDM / PP-TPV.It is an elastomer which is made by blending EPDM and PP process and dynamic vulcanization process.The elastomer has the high elasticity of rubber and can be thermoplastic at high temperature.EPDM / PP-TPV has become one of the most important elastomers in polyolefin thermoplastic elastomer.It can replace traditional crosslinked rubber in sealing strip,cable sheath material,hardware tool handle and other fields,and solve the problem that some traditional cross-linked rubber can not be reprocessed and reused.The development of this product has very important practical significance in production and environmental protection.EPDM/PP-TPV was respectively prepared by three different curing systems of 1,4-bis tertbutylperoxyisopropyl benzene(BIBP),2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane(DBPH)and hydroxymethyl phenolic resin(PF).And the effects of the amount of the main vulcanizing agent on the cross-linking density,micro-morphology,crystalline properties,mechanical properties,compression set and thermal stability of EPDM/PP-TPV were studied respectively.Scanning electron microscopy(SEM)microscopic morphology characterization results showed that the EPDM/PP-TPV prepared by the three vulcanization systems all present a "sea-island" structure with EPDM as the island and PP as the sea,and as the amount of vulcanizing agent increases,The smaller the EPDM particles and the larger the number,the particle size is less than 5 microns.DSC analysis test found that with the increase of the amount of vulcanizing agent,the crystallization temperature of TPV prepared by DBPH and PF showed an increasing trend,and the crystallinity and melting temperature showed a trend of first increasing and then decreasing.The melting temperature of TPV prepared by BIBP And the crystallization temperature both increased first and then decreased,and the degree of crystallinity also showed the same trend.It can be seen from the tensile experiment that with the increase in the amount of vulcanizing agent,the tensile strength of the TPV prepared by the three vulcanization systems all show a trend of first increasing and then decreasing,with the maximum being 6.1MPa,8.2MPa and 7.7MPa respectively,using BIBP and The elongation at break of TPV prepared by DBPH decreases with the increase of the amount of vulcanizing agent,and the minimum values are 449.2% and 403.7%,respectively.The elongation at break of TPV prepared by PF showed a trend of first decreasing and then increasing,with a minimum of 336.5%.It can be seen from the hardness analysis that the hardness of the TPV prepared by the three vulcanization systems has no obvious change.The hardness of the TPV prepared by BIBP is relatively small,floating between 76-79 A,and the hardness of the other two TPVs are both floating around 85 A.With the increase of crosslinking density,the compression permanent deformation of TPV prepared by the three vulcanization systems all showed a downward trend,with the smallest being 56.42%,50.16% and 56.19%,respectively.It can be seen from the thermal weight loss analysis that with the increase in the amount of vulcanizing agent,the thermal stability of the TPV prepared by the three vulcanization systems has been improved to varying degrees,and the thermal degradation temperature is above 230°C.On the basis of the above research,an antibacterial EPDM /PP-TPV material was prepared by melt blending with nano-Zn O as antibacterial agent,and its structure and properties were characterized.SEM photos showed that the material has obvious island structure,and nano-Zn O is uniformly dispersed in the matrix;the performance research results showed that the material has good antibacterial properties,and the antibacterial function values of Escherichia coli and Staphylococcus aureus are 5.6 and 2.0 respectively,and other properties also meet the requirements of customers. |
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