通过高速挤出制备高性能PBS/PETG共混材料

Fabrication of High-performance PBS/PETG Blends by High-speed Extrusion

通过高速挤出技术制备了高性能聚丁二酸丁二醇(PBS)/聚(乙二醇-co-环己烷-1, 4-二甲醇对苯二酸酯)(PETG)共混材料,研究了不同PETG含量和不同螺杆转速对共混材料相区尺寸和性能的影响.研究发现PETG质量分数存在一个最佳用量:即为20%时,随着转速的提高PETG分散相相尺寸从最初的2.27μm逐渐降低到0.89μm.与此同时,共混材料的屈服强度从最初的26.2 MPa增加到33.4 MPa,提高了27.5%.断裂伸长率也从最初的13.3%提高到133.3%,实现了从脆性断裂到韧性断裂的转变.而当PETG的质量分数为10%或30%时,提高转速对PETG分散相的相尺寸减少不多,对共混材料力学性能有一定提升.最佳用量的存在表明高速挤出引起的相区尺寸减少是一个破碎与聚并动态平衡的过程.将不同的组成和加工的转速下获得的共混物的屈服强度与分散尺寸作图,发现它们成近似的反比关系,进一步证明PETG减小分散相相尺寸对共混材料性能提升的重要性.

Blends based on poly（butylene succinate）（PBS）and poly（ethylene glycol-co-cyclohexane-1,4-dimethanolterephthalate）（PETG）were successfully fabricated by a special twin screw extruder.Effects of PETG content and rotating speed on the dispersed size and mechanical properties of the PBS/PETG blends were investigated.The average diameter of PETG phase showed a downwards trend from 2.27μm to 0.89μm with increasing rotating speed from 150 r/min to 900 r/min for a blend with 20 wt%of PETG.Meanwhile,the yield strength of the blend was raised from 26.2 MPa to 33.4 MPa.In addition,the elongation at break was also promoted from 13.3%to 133.3%,which indicated a transformation from brittle fracture into ductile fracture as accomplished by high speed extrusion.However,the decrease of the dispersed PETG size was very limited by increasing rotating speed for the blends containing 10 wt%or 30 wt%of PETG.As a result,the yield strength and the elongation at break showed only limited increase in the obtained blends.The relationship between the size of the dispersed phase and mechanical properties of the PBS/PETG blends prepared with different components and at different rotating speeds were analyzed comprehensively.A nearly linear relationship was found between the yield strength and the diameter of the dispersed phase,disregarding the composition and rotating speed.This demonstrated again the importance of the size of the dispersed phase in determining the property of PBS/PETG blends.GPC and DSC results indicated no obvious change in molecular weight and crystallinity of PBS by increasing rotating speed,and the observed property change of the blends was well explained by the change of dispersed phase size induced by high speed rotating.It should be noted that the high speed rotating induced change in the size of the dispersed phase was thermodynamically unstable.The stability of the blends will be investigated in our future work.