Epoxidized Trans-1,4-poly Isoprene: New Synthetic Methodology And The Property Of The Resulting Polymer

Trans-polyisoprene(TPI)is a crystalline material at room temperature,exhibiting high modulus and high tensile strength properties.Applying it to a tire could reduce the rolling resistance of the tire,but its wet skid resistance decreases as well.Studies have shown that the appropriate epoxidation of TPI can not only maintain TPI low rolling resistance performance,but also enhance its properties,such as wet skid resistance,adhesiveness,oil resistance,air tightness,abrasion resistance and other properties.The traditional epoxidation method mainly used the peroxide acid as the epoxidation system.In the acidic condition,the epoxy group will undergo some side reactions such as over oxidation,chain scission and furan ring formation,which maybe affect the mechanical properties of the ETPI.In order to overcome the above problems,a weak base epoxidation agent made in laboratory was used to replace peroxy acid used in traditional methods under weak alkaline conditions.In this work,relationship between epoxy degree and mechanical properties was explored.Results showed that the addition of appropriate amount of ethyl acetate or chloroform to the reaction system could improve the degree of epoxidation.Epoxy degree as high as 32% in ethyl acetate and 51% in chloroform could be obtained,respectively.Compared with the traditional method(using the peroxide or acetic acid as the oxidant),the new synthetic method greatly suppressed the side reactions such as over oxidation,chain scission and furan ring formation,which in turn greatly improved the mechanical properties of the resulting ETPT.The crystallization properties of ETPI were tested by DSC and XRD.The results show that the crystallinity of ETPI products will decrease with the increase of epoxy degree.Mechanical tests show that the raw ETPI prepared via this novel method possesses a tensile strength over 20 MPa,almost 7 fold stronger than that of ETPI prepared using traditional method.Improved wet-skid resistance was observed with the increase of epoxy degree for that of ETPI prepared via the new method.At the same time,rolling resistance was hardly changed.Oil resistance tests explored that the oil resistance of ETPI was significantly increased when the epoxy degree was greater than 15%.Studies on the properties of the blend of ETPI and NR have discovered that the addition of a small amount of ETPI can improve the processability and aging resistance of NR,but maybe the fatigue resistance and wear resistance are deteriorated.The application of ETPI in flat tire,compared to the original production formula can improve the rubber modulus,tensile strength and tear strength,and aging resistance performance will be enhanced,but the heat is much higher than the original production,.