| A series of PA6-PEG segmented copolymer was synthetized by anionic polymerization, with the aprolactam and polyethylene glycol (PEG) as the main raw material in the paper. The synthesis process route, the structure and effects of the feed ratio on thermal performance, crystalline properties, mechanical properties and water absorption of the copolymer were focused on.The structure of the polyamide copolymer was studied. IR spectra of the product showed that a new ester linkage appeared and -OH group of polyether disappeared, which indicated that the product was a segmented copolymer linked by ester group.Researches on the synthesis process showed that the optimal reaction conditions were temperature:around 160℃; vacuumizing time to effectively remove water:60 min every step; co-catalyst:1.5mol%. The study on differential scanning calorimetry showed that The melting point declines regularly when the PEG mass percentage was less than 20%, however it had big volatility when the percentage was more than 20%, which could indicate that the caprolactam/PEG ratio was not the decisive factor of the melting point. The melting point of the copolymer reduced with the lower relative molecular mass of PEG when the caprolactam/PEG ratio was the same. With the increase of the PEG mass percentage, the tensile strength decreased accordingly while the breaking elongation, the response rate, and the water absorption increased first, and then decreased. Through the analysis by XRD, the resulted could be got that it was easier to get thermodynamically unsteady y polymorph products by anionic polymerization. |
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