【作者】 刘卫卫；

【导师】 李齐方； 金日光；

【作者基本信息】 北京化工大学 ， 材料工程， 2012， 硕士

【摘要】 为提升国产通用碳纤维用PAN原丝的力学性能，原丝需要经过再次沸水牵伸、再次水洗及干燥致密化、再次高温高压蒸汽牵伸等工艺处理。实验结果表明：1、在实验室设备条件下，沸水牵伸、干燥致密化和高温高压蒸汽牵伸工艺分别最高能把原丝强度提高31.25%、35.6%和39%。这说明国产通用碳纤维用原丝的质量有提升的空间，可以通过再次原丝工艺流程，提高其质量。2、沸水牵伸实验中，随拉伸比的增大，纤维断裂伸长率及直径有下降的趋势，纤维的强度及结晶度先升高后降低，其转折点在12%-14%之间，之后会过牵。停留时间设定在80s比较合适，拉伸比11.59%时，纤维强度提高了31.25%，结晶度为70.08%，此时纤维直径为10.982μm，断裂伸长率为9.4%。3、水洗因使丝束增韧，与致密化起到相反的作用，不利于原丝力学性能的升级；不同温度下，随致密化时间的增加，丝束强度先增大后减小，55s时丝束强度提高最大；确定致密化时间55s时，在140-150℃温梯下丝束强度最大，约提升初始原丝的35.6%。增大温度区间，纤维的结晶度及强度都较高，并且结晶尺寸增加不多，有利于生产优质原丝。4、蒸汽介质下纤维承受的拉伸比要比干热牵伸时大，这是因为因水分子的增塑作用。因水分子的增塑作用，135℃和150℃时蒸汽牵伸的纤维强度大于干热牵伸时的强度。蒸汽介质中，135℃，15%拉伸比时，得到的原丝综合性能最好，强度为1.023GPa，是初始原丝强度的1.39倍，直径为10.813μm，并且丝束比较均匀，纤维表面良好。更多还原

【Abstract】 To enhance mechanical properties of PAN precursor using domesticgeneral carbon fiber, the PAN precursor fiber was treated again by processingssuch as boiling water stretching, water-washing and drying densification, andhigh-temperature and high-pressure steam stretching. The experimental resultsshowed as follows：1. Under conditions of the laboratory equipments, boiling waterstretching, drying densification and high-temperature high-pressure steamstretching process, could make the strength of initial precursor fibermaximally increase by31.25%,35.6%and39%. This showed that, the qualityof precursor fiber of domestic general carbon fiber could be improved throughsecond process.2. In the boiling water stretching, with the stretch ratio increased, theelongation at break and the diameter of fiber had a downward trend, and thestrength and crystallinity degree of fiber first increased and then decreased.The turning point was between12%-14%, and then over stretching occured.The residence time at80s was appropriate, and at stretch ratio11.59%, the initial precursor fiber strength increased by31.25%, and crystallinity degreewas70.08%, and the fiber diameter was10.982μm, elongation at break was9.4%.3. The water-washing, which played opposite effects against densificationbecause of toughening fiber, went against the mechanical properties upgradingof precursor fiber. Under different temperatures, the strength of fiber increasedfirst and then decreased with the increase of densification time, and the fiberstrength reached maximum at55s. When the densification time was55s, fiberstrength reached maximum0.998GPa at the140-150℃temperature gradient,and the strength of initial precursor fiber increased by about35.6%. Increasingtemperature range can make the strength and crystallinity degree of fiber arehigher, and crystallization size increase not so much, and this is beneficial tothe production of high quality silk.4. Fiber under steam medium could bear larger stretch ratio than the oneunder dry heat because of the plasticizing effect of water molecules. Due tothe plasticizing effect of water molecules, the fiber strength by steamstretching was greater than the one by dry heat stretching at135℃and150℃.In the steam medium,135℃,15%stretch ratio, the fiber of the best overallperformance could be obtained, and the fiber strength was1.023GPa,diameter was10.813μm, and the fiber tow was relatively uniform, surfacewas good.更多还原