| Engineering plastics poly(hexamethylene adipamide) (polyamide 66, PA66) exhibits excellent properties, such as a high rigidity (tensile yield stress, flexural modulus), excellent abrasion resistance, heat resistance, chemical resistance etc. It has been widely applied in machinery, electronic equipment, automobiles, and other fields. In order to reduce the cost,enlarge the using ranges and satisfy the more requirements for performance, blending and filling modification for PA66 has become a focus of researching high performance and practicality of engineering plastics.At present, polyethylene terephthalate (PET) in the packaging area is a rapid growth in consumption, due to the short shelf life of PET bottles, but also a one-time use, the consumption of waste PET that still maintain good performance was also increasing at the roughly same rate. If technical methods used properly, using rPET chips as a filling material, it can be prepared PA66-based engineering plastics(PA66/rPET) with high performance/cost, but recyced PET bottles. So it has the important economic, social significance and academic value. But generally speakig, the properties of PA66/rPET blends falls short of expections due to the interface structure of PA66 and PET and crystallization of PET based on the analysis of literature. Therefore, it is urgent to form a proper interface structure and accelerate the crystallization of rPET for preparing PA66/rPET blends with better properties than that of PA66.In order to significantly improve the toughness and maintain the rigidity or reduce the rigidity as little as possible(Tensile Yield Stress, Flexural Modulus), PA66/rPET blends of this work should have the following structural characteristics: adding rPET to PA66, reactive compatibilizing toughener(RCT) we prepared is also added at the same time. RCT has chemical reactions and chemical bonds connection with PA66 and rPET. RCT also can significantly improve the toughness and maintain the rigidity of PA66/rPET. Using a suitable reactive blending technology, RCT can concentrate in the interlayer between PA66 and rPET and form the moderate flexible interlayer with high interfacial adhesion by the effects of energy and entropy. The emergence of such structure can avoid that rigid interface induce the formation of micro-cracks of resin matrix in the interface area, transfer stress between the matrix resin and rPET. The resin matrix mainly exhibits shear yield deformation under the external forces, the good interface adhesion can effectively terminate shear deformation, crazing and absorb impact energy. In addition, in order to change the crystallization behavior and accelerate the crystallization rate of rPET in the processing, it is necessary to add a high-performance, appropriate amount of rPET nucleating agent to improving the rigidity of materials effectively.Based on the above designs, the reactive compatibilizing toughener was synthesized in the low-viscosity reaction system through the technique "grafting copolymerization, reactive blending" using PP, elastomer, containing epoxy functional groups of bridge agents and so on. PA66/RCT/rPET/Ta blends was prepared using PA66, RCT, rPET and talcum by different thermal mechanical reactive blending technology. The structure and properties of RCT and PA66/RCT/rPET/Ta composites were investigated by means of fraction extraction, IR, TEM, SEM, PLM, DSC and mechanical properties measuring. The main results and conclusions are as follows:(1) The compositions of RCT are composed of unreacted PP and elastomers, graft polymers of PP and elastomers with bridge agents, cross-linked copolymer of PP and elastomers, elastomers and elastomers by polymer bridge conjuction using bridge agents, homopolymer and copolymers of bridge agents.(2) Considering sodium benzoate, talcum, bentonite and titanium on crystallization behavior and mechanical properties of rPET, Talcum powder is the optimal nucleating agent for rPET. Talcum makes Tpcc reduce 13.6℃, Scc increases to 15.4, Tpmc increases 25℃,Smc increases to 6.1.The tensile yield stress(TYS), flexural modulus(FM) of rPET/Ta blends increases 0.24 times,0.22 times as high as those of the pure rPET respectively while thermal deformation temperature increased 3.1℃.(3) RCT, rPET and PA66 have chemical bonds through the chemical reaction between the epoxy functional group in RCT, the bottom amide groups and carboxyl groups of PA66 chains and the bottom hydroxyl groups and carboxyl groups of rPET. The moderate flexible interplay with high interfacial adhesion has been formed between the PA66 and rPET.(4) RCT has the greater degree of response with rPET than that with PA66. The mechanical properties of PA66/RCT/rPET/Ta and reactive blending technology are closely related. The blending technology of PA66 in advance reactive extrusion with some of RCT, and then with rPET,talcum powder and the remaining RCT shows the best.(5) When using the best blending process, along with the increase in RCT content, The tensile yield stress, flexural modulus of PA66/RCT/rPET/Ta blends reduce gradually while the notchod Izod impact strength increases gradually. The mechanical properties of PA66/RCT/rPET/Ta blends with ratio 66.5/5/28.5/5 of PA66/RCT/rPET/Ta shows the best. The tensile stress, flexural modulus and notchod Izod impact strength of PA66/RCT/rPET/Ta are 0.96 times,1.22 times and 1.41 times as high as those of pure PA66 respectively.(6) When using the best blending process, with the increase of RCT added, Tg of PA66 in PA66/RCT/rPET/Ta is higher than pure PA66 and the extent of increase first increases and then reduces; Tmcp increases 11.1～13.3℃and the extent of increase reduces gradually. Tg of rPET in PA66/RCT/rPET/Ta is lower than pure rPET and the extent of decrease increases gradually; Tccp reduces 26.1～28.1℃and the extent of decrease increases gradually; Tmcp increases 11.7～18.9℃and the extent of increase reduces gradually.
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