| As new materials developed in the 20th century, polymers has been widely used in electronic appliances, automotive and aviation, aerospace and other fields with its excellent overall performance and process ability. With the rapid development of high performance products in polymer-related industries, performance requirements are increasingly high. Many of the pure resin has been difficult to meet the needs of related industries. At the same time, the development of a new polymer is difficult due to the limited of raw materials sources. Therefore, modification of existing polymer materials is an important topic in polymer science to enhance the performance of the material or endowed with new functions in order to obtain high comprehensive performance.PET is one of the most important synthetic materials, people have began the study of application and development on PET as an engineering plastics since the 1960s. As engineering plastics, PET has many excellent properties. It can be recycled, abrasion resistance, impact resistance, formability and good resistance to creep under the load. Currently, PET has been widely used in electronic appliances, automotive and machinery industries. However, the shortcomings such as brittleness and poor impact toughness limit its widespread use as engineering plastics due to the rigidity of PET macromolecular chains.In the preparation of toughened PET engineering plastic, the most commonly used method is the incorporation of elastomers. However, there is a strong interfacial tension between the polar PET and non-polar elastomers. In order to improve the interface bonding of PET matrix and elastomer, an appropriate method must be adopted, such as the use of functionalized elastomers or adding a third substance as compatibiliter. In addition, irradiation can occur grafted or cross-linking reaction between blend components which lead to the improvement of system compatibility and irradiation compatibilization is simple compared with chemical compatibilization.In this work, PET and three kinds of elastomers (E-MA-GMA,SEBS,SEBS-g-MA) have been chosed as main materials and multi-functional monomers C was included as strengthen cross-linking agent. The composites of PET/E-MA-GMA/C, PET/SEBS/C, PET/SEBS-g-MA/C were respectively prepared with twin-screw extruder. And enhanced irradiation compatibilization was adopted to improve phase interface of elastomer and PET matrix. Mechanics, thermodynamics, gel extraction and scan electron microscope (SEM) were carried out to study the mechanical properties and structure of composite materials and their mutual relationship. Meanwhile, elastomer content, cross-linking agent content and absorbed does were investigated to study the composites performance and structural effects, and interactions between various components interface were also analyzed. In addition, study whether functional groups compatibilization and enhanced irradiation compatibilization together improve the compatibility of PET/E-MA-GMA/C and PET/SEBS-g-MA/C system.In the PET/E-MA-GMA binary system, when the addition of E-MA-GMA followed by irradiation, the impact strength of composites was improved and the maximum could be up to 66.3KJ/m2. The degree of improvement was highest when the elastomer content from 10wt% to 15wt%. When the addition of cross-linking agent C the mechanical properties of composites were further improved. In the 85/15 system with cross-linking agent C content of 1wt% and irradiated dose of 5,70kGy, the impact strength of composites were the highest, 80.1KJ/m2 and 88. KJ/m2 respectively;In the 80/20 system with cross-linking agent C content of 1wt% and irradiation dose of 5,100 kGy, the impact strength of composites were 86.3KJ/m2 and 106.8KJ/m2 respectively. The thermal mechanical analysis of blends also shows that compatibility of system has been improved by the addition of cross-linking C and the introduction of irradiation. Under this condition, there were grafting and cross-linking structures produced in the system and formed a large crossliking network, due to the role of enhanced radiation crosslinking. The gel content coincided with mechanical properties as well. In addition, SEM images also showed a large number of clear plastic deformation zone, which could absorb a lot of energy, so the impact strength was. greatly enhanced. When the crosslinking agent content was low, compatibilization effect of radiation and elastomer toughening modifier compatibilizer effect could match with each other and played to improve the system compatibility together, and its impact strength greatly increased in turn. But the tensile strength and Young's modulus of blends decreased.From the mechanical test results of the PET/SEBS/C system with the SEBS content of 20wt%, crosslinker content of 1wt%,we can see that its impact strength value was high at 50kGy, the gel content was in a moderate range as well.From the SEM photos, compared with system without irradiation or without cross-linking agent, SEBS of the radiation crosslinked system dispersed uniformly in the matrix, and the size significantly reduced, the interface was fuzzy between two phases, the interface bonding was well and the mechanical properties were corresponding enhancement. But the tensile strength and Young's modulus of blends decreased.From the mechanical properties of the PET/SEBS-g-MA system, we can know that its impact properties was improved by adding the SEBS-g-MA alone. In PET/SEBS-g-MA/C ternary complex system with SEBS-g-MA content of 20wt% and crosslinking agent content of 1wt%, its impact strength was the greatest at 10kGy. Under these conditions, the SEM images show that size of elastomer particles was small, and some holes were occurred when the particles left off. The hollowing of elastic particles led to the matrix shear yield. Elastomer particles dispersed in PET and formed sea-island structure with matrix, improved the impact properties of the composite system. And its gel content was in a suitable range as well. But the tensile strength and Young's modulus of blends decreased.Contrast to PET/SEBS and PET/SEBS-g-MA, when added elastomers alone and irradiated, the toughening effect of SEBS-g-MA slightly better than that of SEBS. When added the cross-linking agent, the toughening effect of the PET/SEBS/C system was better than that of PET/SEBS-g-MA/C system. In the same crosslinking agent that C content was 1wt%, the impact strength of the PET/SEBS-g-MA was improved lightly to the PET/SEBS system. This may be due to the Malay anhydride in the SEBS-g-MA reacts with the PET hydroxyl end first. And the reaction may affect the multi-functional monomers to promote radiation compatibilization, when the content of TMPTA was lower and irradiated. So they couldn't match well, and the interface compatibilization effect was not obvious.
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