| As a Chinese unique nylon, nylon 1010 has good abrasion resistance, self lubrication and low temperature properties, but it has low notched impact strength due to its low crack propagation energy. In this work, ethylene-vinyl acetate copolymers (EVA) and its maleated version (EVA-g-MAH) were chosen as impact modifiers to toughen nylon 1010 through melt blending, and nylon 1010 blends with high notched impact strength were obtained. The related toughening mechanism was systematically investigated, and the interparticle distance (ID) model was used to reveal the relationship between the notched impact strength and morphology of nylon 1010 blends.Firstly, ethylene-vinyl acetate rubber with 40 wt% VA content (EVM 400) was used as impact modifier for nylon 1010 and its toughening effect was investigated. The notched impact strength of nylon 1010/EVM 400 blends increased with increasing EVM 400 content. A brittle-ductile transition (BDT) was observed when the EVM 400 content increased from 40 phr (per hundred nylon 1010) to 80 phr, and the notched impact strength increased from 22.8 kJ/m2 to 62.3 kJ/m2. For nylon 1010/EVM 400 (100/20) blend, the notched impact strength increased significantly after the addition of EVA-g-MAH, and a BDT was also observed when EVA-g-MAH content increased from 2.5 phr to 5 phr. Scanning electron microscope showed EVA-g-MAH significantly improved the dispersion of EVM 400 in nylon 1010 matrix, and the number average diameter (dn) of EVM 400 particles decreased significantly with increasing EVA-g-MAH content. The ID model showed that a sharp BDT was observed for nylon 1010/EVM 400 and nylon 1010/EVM 400/EVA-g-MAH blends when the interparticle distance was about 0.2μm, independent of the addition of EVA-g-MAH. Then, the impact modifiers used were expanded to a series of EVA with different VA content and Mooney viscosity. The VA content and Mooney viscosity of EVA significantly affected the notched impact strength of nylon 1010/EVA/EVA-g-MAH (80/15/5) blends. The nylon 1010/EVA/EVA-g-MAH (80/15/5) blends with high notched impact strength (over 60 kJ/m2) were obtained when the VA content ranged from 28 wt% to 60 wt%. The effect of VA content on the notched impact strength of nylon 1010/EVA/EVA-g-MAH (80/15/5) blends was related to the glass transition temperature (Tg) and crystallinity of EVA. For nylon1010/EVA/EVA-g-MAH (80/15/5) blends with EVA with the same VA content, high viscosity of EVA usually led to low notched impact strength due to the serious aggregation of EVA in nylon 1010 matrix. A relationship between the notched impact strength and morphology of nylon 1010/EVA/EVA-g-MAH (80/15/5) blends was generally in agreement with the ID model.The impact modifiers used were further expanded to different elastomers, and the toughening effects of different elastomers on nylon 1010 were compared. Ethylene-1-octene copolymer (POE), styrene-ethylene-butadiene-styrene block copolymer (SEBS), EVM and also their corresponding maleated versions (POE-g-MAH, SEBS-g-MAH, and EVA-g-MAH) were melt blended with nylon 1010. The elastomer type significantly affected the notched impact strength of nylon 1010/elastomer/maleated elastomer blends. EVM had the best toughening effect on nylon 1010 in the absence of maleated elastomers were added. Among all the nylon 1010/elastomer/maleated elastomer blends, nylon 1010/SEBS-g- MAH (80/20) blend had the highest notched impact strength at room temperature, and nylon 1010/POE-g-MAH (80/20) blend had the best low temperature toughness. The modified essential work of fracture (EWF) was used to characterize the fracture behavior of nylon 1010/elastomer/maleated elastomer blends. The limited fracture energy (u0) of the blends increased with increasing dn when the dn was below 1μm and decreased sharply when dn was over 1μm, while the dissipative energy density (ud) increased with decreasing dn. The energy consumed in the outer plastic zone was the main part of dissipated energy during the fracture process, and the shear yielding of nylon 1010 matrix was the main toughening mechanism.Although the notched impact strength of nylon 1010 could be significantly increased by blending nylon 1010 with suitable elatomers, the stiffness of nylon 1010 decreased obviously due to the addition of elastomers. A good trade-off between stiffness and toughness was obtained by the combination of POE-g-MAH and glass fiber (GF). The yield strength, flexural strength and modulus almost linearly increased with increasing GF content. The modified EWF model was used to characterize the fracture behavior of nylon 1010/POE-g-MAH/GF composites. For nylon 1010/POE-g-MAH/GF composites, with increasing GF content, ud gradually decreased and u0 reached the maximum value at the GF content of 10 wt%. The critical stress intensity factor of nylon 1010/GF composites increased with increasing GF content, suggesting GF could enhance the crack resistance of nylon 1010. POE-g-MAH and GF significantly increased the toughness and stiffness of nylon 1010, and decreased the water absorption ratio of nylon 1010.The effect of Polyhedral Oligomeric Silsesquioxane (POSS) on the thermal stability of nylon 1010 was also investigated. POSS increased the integral procedure decomposition temperature and char yield at 800 oC of nylon 1010. The Doyle-Ozawa and Friedman methods were used to characterize the non-isothermal decomposition kinetics of nylon 1010 and its composites in nitrogen. The non-isothermal decomposition of nylon 1010 in nitrogen was first order reaction. POSS significantly increased the activation energy of nylon 1010 but had little effect on the reaction order. The lifetime of nylon 1010 and nylon 1010/POSS composites decreased with increasing temperature. POSS significantly prolonged the lifetime of nylon 1010, especially at relatively low temperatures. TG coupled FTIR showed the non-isothermal decomposition products of nylon 1010 were polyamide oligomers, and POSS did not change the formulation of the decomposition products.Finally, the reaction between EVM and nylon 1010 during melt blending was also investigated. Nylon 1010/EVM 8939 (VA content, 90 wt%) (50/50) blends were prepared at different mixing temperatures. Both the tensile strength and the elongation at break of nylon 1010/EVM 8939 (50/50) blends went through maximum values with increasing mixing temperature. p-toluenesulfonic acid (TsOH) significantly decreased the tensile strength and elongation at break of nylon 1010/EVM 8939 (50/50) blends, while triphenyl phosphate obviously increased the elongation at break of nylon 1010/EVM 8939 (50/50) blends. An obvious reaction was observed between EVM and TsOH during melting mixing at elevated temperature. The related reaction mechanism was further studied and could be interpreted as follows: EVM was hydrolyzed in the existence of TsOH, and then the hydrolyzation product was intra-molecule dehydrated to form conjugated double bonds. Such conjugated double bonds contributed many excellent properties to EVM materials, which has potential application in future.The innovations of this dissertation are list as follows:(1) The impact modification of nylon 1010 had not been widely investigated. In this work, ethylene-vinyl acetate rubber with 40 wt% VA content (EVM 400) was firstly used as impact modifier to toughen nylon 1010, and nylon 1010/EVM 400 blends with high notched impact strength (over 50 kJ/m2) were successfully prepared. The relationship between the morphology and the notched impact strength of nylon 1010/EVM 400 blends was revealed by the interpaticle distance (ID) model, and the critical ID for EVM 400 toughened nylon 1010 was around 0.2μm, which has not been reported before.(2) The impact modifiers used were further expanded to a series of ethylene-vinyl acetate copolymer (EVA) with different VA content (0 ~ 90 wt%) and Mooney viscosity. Nylon 1010 with high notched impact strength (over 50 kJ/m2) was prepared when the VA content of EVA ranged from 28 wt% ~ 60 wt%. The toughening effects of EVA with different VA content on nylon 1010 were further related to the glass transition temperature and crystallinity of EVA.(3) Maleated ethylene-1-ocetene copolymers (POE-g-MAH) and glass fiber (GF) were used to modify nylon 1010. After the addition of POE-g-MAH and GF, the notched impact strength and the yield strength of nylon 1010 significantly increased, while the water absorption ratio of nylon 1010 obviously decreased. Nylon 1010 composites with good comprehensive properties were successfully prepared. The modified essential work of fracture and linear elastic fracture machanics were used to investigate the fracture behavior of nylon 1010 composites. The effect of GF content on the fracture parameters was investigated.(4) Polyhedral Oligomeric Silsesquioxane (POSS) was firstly used to enhance the thermal stability of nylon 1010. The non-isothermal decomposition kinetics of nylon 1010 and nylon 1010/POSS composites in nitrogen were investigated. POSS significantly increased the activation energy but had little effect on the reaction order.(5) Exploring research was carried out on the reaction between EVM and nylon 1010. The reaction between EVM and TsOH during melt mixing was also invesigated, and related reaction mechanisms were studied in terms of NMR, TGA-FTIR and etc. The reaction between EVM and TsOH contributed EVM many excellent properties such as increased solvent resistance, glass transition temperature, mechanical properties and decreased volume resistivity, which has potential application in future.
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