湿热环境对抽油杆CF/VE拉挤复合材料的影响

研究了95℃蒸馏水环境中油田抽油杆用碳纤维/乙烯基酯树脂(CF/VE)拉挤复合材料的吸湿特性,以及材料的力学性能和动态热机械性能的变化,并观察了湿热老化前后该复合材料的表面和断口形貌。结果表明,CF/VE拉挤复合材料的吸湿行为符合菲克第二定律,材料的平衡含湿量M_m约为1.046％,水分在复合材料中的扩散系数约为2.233×10-6 mm2/s;复合材料的性能下降趋势与吸湿率的增加趋势相对应,浸泡1176 h后,弯曲强度和层间剪切强度的最终保留率分别约为49％和54％;DMTA及SEM结果表明,湿热环境导致该复合材料发生基体溶胀、塑化和界面脱粘,引起基体和界面形貌的变化,但未发生化学老化。 

EFFECTS OF HYGROTHERMAL ENVIRONMENT ON PULTRUDED CARBON FIBER/VINYLESTER RESIN COMPOSITE USED FOR SUCKER RODS

The absorption characteristics and the changes of the static mechanical properties and dynamic mechanical thermal properties of the pultruded carbon fiber/vinylester (CF/VE) composite, which is used for sucker rods in oil field, were studied during distilled water immersion at 95℃. The surface and fracture morphologies of the as-received and immersed composites were observed by using SEM. The results show that the composite obeys the second Fick's law in terms of absorption behavior, having an equilibrium moisture content of 1.046% and a diffusivity of 2.233×10-6 mm2/s. The decrease in the properties of the composite is very relative to the increase in its moisture content. After being immersed for 1176 hours, the composite has a reservation of interlaminar shear strength (ILSS) and flexural strength of 54% and 49%. The results of dynamic mechanical thermal analysis (DMTA) and SEM show that hygrothermal environment causes the swell and plasticization of the matrix, interfacial debonding and resultant microstructure changes of the matrix and interface. No chemical aging was found.