| Material science is an important academic in nowadays. As the fast development of technology, higher and better properties of material are required. Many single materials have already cannot meet the demands completely, and the development of new ones with applied value faces a great difficulty. So modification of existed materials is a good choice, which can raise the properties of materials to adapt application requirements. Fiber reinforced composites appeared under this background.The mechanical, thermal and other properties of polymer could be enhanced significantly. More and more polymer composites are used in production and living.Poly (ethylene terephthalate) is a milky white or light yellow polymer with high crystallinity and smooth surface. Since 40's in 20 centuries, PET has been used as terylene for more than 60 years and becomes the one with most usage in three synthetic fibers. Along with the science development and technology progress, the usage of PET has been no longer limits as fiber, but expands to more and more fields. Especially in the development of engineering plastics, because of its good comprehensive properties PET has attracted more and more concerns. But there are two shortcomings of PET when used as engineering material. The one is the poor impact strength, and the other is the slow crystallization velocity. How to improve these properties is the key problem in PET modifications. The impact property can be improved significantly when PET is modified with glass fiber, and the comprehensive properties can be enhanced further. FR530 is a typical example. Moreover, glass fiber in composites could act as nucleating agent, and increase the crystallization velocity of PET, which has been reported in literatures. However, the harm of glass fiber to respiratory system cannot be neglected. Therefore whether a environment-friendly fiber with the properties similar to glass fiber could be found is a new problem. Appearance of basalt fiber (BF) provides us with a potential opportunity. BF is produced by melting drawing from volcano extrusive rock. Its comprehensive properties equals to glass fiber. Whether or not BF could replace glass fiber to produce PET resin with high performance causes our thinking.Composites of PET reinforced by BF were prepared by melting blending with two-screw extruder in this work. And irradiation compatibilization was introduced to improve the adhesive force of matrix and fiber in order to produce PET engineering plastic with good properties. Mechanical characterization, gel extraction, scan electron microscope (SEM) were applied to research the changes of structure and mechanical properties. Differential scanning calorimetry (DSC) was used to study the isothermal and non-isothermal crystallization behavior and the influence of irradiation compatibilization on crystallization behavior, as well.Mechanical characterization showed that PET could be reinforced by BF effectively. As the increase of BF, the impact strength of composites was raised gradually. The changes of tensile and flexural properties were similar to impact properties. As the content of BF reached 30 wt%, the mechanical properties of composites were about twice as high as the ones of neat PET. Nevertheless, irradiation could not improve the mechanical properties of PET/BF binary composites any more.The additive of crosslinking accelerant A followed by irradiation led further improvement of mechanical properties of composites. However, the influence of radiation dose and A amount on properties of PET/BF/A ternary composites was not obvious. The optimum proportion of PET/BF/A was 70/30/3(wt/wt/wt), and the best dose was 30 kGy. And in this case, the properties of composites surpass the ones of imported materials of the kind, for example, FR530 and CN9030. So this work is in possession of very good application prospect.The results of gel extraction and SEM were in accordance with the changes of mechanical properties. No gel was generated after irradiation, and the improvement of interface could not be observed in SEM photographs. But the addition of A followed by irradiation, gle appeared. And the interfacial adhesive was enhanced compared with PET/BF composites, which could be seen in SEM photographs. Gel fraction reached the maximum when BF content was 30 wt%. As the increase of radiation dose and A, gel fraction hardly changed, which was coincident with changes of mechanical properties, as well.The results of isothermal crystallization dealed with Avrami equation confirmed that fiber acted as nucleator in composites. With the increase of fiber content, the crystallizating rate accelerated gradually. But the crystallization mechanism was not changed by fiber obviously. As the rise of temperature, crystallization of composite transformed to two or three dimensions. For the improvement of matrix-fiber interface adhesive, nucleation ability of composite system was enhanced, and further acceleration of crystallization appeared after the addition of A followed by irradiation.The results of non-isothermal crystallization dealed with the method of Jeziorny showed that the addition of 30 wt% BF to PET led acceleration of crystallization. When A was added, which was followed by irradiation, crystallization rate constant augmented and half-time of crystallization shortened significantly. The reason was the improvement of interface and the enhancement of nucleation ability, which was the same as isothermal crystallization.
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