Regulation Of ? Nucleating Agent On The Crystallization Behavior Of Thermoplastic Elastmmers

Dynamically vulcanized thermoplastic elastomer(TPV)is a kind of thermoplastic elastomer prepared by dynamic vulcanization with a small amount of plastic(20-50%)as the continuous phase matrix and a large amount of rubber(50-80%)as the dispersed phase.The products have excellent performance,and are currently receiving more and more attention,and have been widely used in various fields such as medical treatment,electronics,auto parts and so on.With the gradual deepening of applications,the requirements for performance are gradually increasing.However,the development of a new system of TPV will consume financial and material resources,and the industrialization time will be longer.Therefore,more and more attention is paid to the research on the post-processing modification of thermoplastic elastomers.However,current research mainly concentrate on adjusting the size of the rubber phase and the compatibility of the two phases,while less attention has been paid to the continuous phase of the plastic.As a continuous phase,thermoplastics generally have crystalline behavior.Therefore,the crystalline behavior of the plastic matrix can be adjusted to improve the performance of the material and broaden the application field of the material.It is of great significance to enlighten the study of ? crystal toughened polypropylene to study the influence of ? crystal form on thermoplastic elastomers.The main research of this subject is as follows:(1)By adding 0.1 wt%rare earth ? crystal nucleating agent WBG-? to two kinds of POE/PP TPV with different rubber-plastic ratios to control the crystallization behavior of the plastic phase in the system,and then introduce ?crystals into the system.The effect of ? crystal form on the mechanical properties and elasticity of TPV.Through the research of POE/PP TPV with a rubber-to-plastic ratio of 60/40,it is found that the introduction of ? crystal can improve the tensile strength and elasticity of TPV.XRD is used to test the crystallization behavior.When the relative content of ? crystals is 71%,the tensile strength of TPV is increased from 16.0MPa to 22.1MPa,the elasticity was also improved,and the hysteresis loss is reduced from 67.8%to 61.3%.We introduced ? crystal to POE/PP TPV with a rubber-to-plastic ratio of 50/50 and found the same effect.However,through the elasticity test,it is found that the hysteresis loss of TPV with a rubber-plastic ratio of 50/50 is reduced from 77.1%to 65.4%,and the degree of decrease is higher than that of POE/PP TPV with a rubber-plastic ratio of 60/40,indicating that ? crystals are in plastics.The effect of improving elasticity is more significant in the system with higher content.(2)we focused on the structural analysis of the POE/PP TPV with a rubberto-plastic ratio of 60/40.The rubber network structure was characterized by RPA and the atomic force was used for phase structure analysis.It is found that the introduction of ? crystals had an effect on the rubber network structure and phase state.The structure has no effect.The tensile infrared test of the material was carried out,and it is found that the TPV crystals containing a crystal form gradually de-orientated,and as the degree of stretching increases,the TPV crystals introduced into ? crystals gradually deform and re-orientate again,thus affecting the material.To enhance the effect.Because the ? crystal structure is loose,there is no obvious interface between adjacent spherulites,and the crystals are interspersed and interwoven together,so under lower strain,it helps to absorb and dissipate energy under stress,and then Improve the flexibility of TPV.(3)Quenching experiments were performed on two POE/PP TPVs with different rubber-plastic ratios at 125?.It was found that the relative content of? crystals can be further increased after quenching.For the rubber-plastic system of 60/40 TPV,After quenching,the tensile strength is increased to 24.4MPa,and the hysteresis loss is reduced from 67.8%to 60.3%.For the rubber-plastic system of 50/50 TPV,the elastic improvement effect is more obvious,and the hysteresis loss is reduced from 77.1%to 63.2%.Therefore,after quenching,the overall mechanical properties and elasticity of the material have been further improved.And quenching will not have any effect on the structure of the sample.