Impregnation of thermoplastic resin in jute fiber mat

Impregnation rate of thermoplastic resin(polypropylene)in jute fiber mat and influence of relative factors on impregnation were studied,aiming to develop the continuous melt impregnation technique and to investigate the effect of impregnation rate and temperature on processing conditions and mechanical properties of natural fiber mat-reinforced thermoplastics.Influence of pressure on porosity of fiber mat and effect of melt viscosity on impregnation rate were also investigated.The modified capillary rheometer was used as apparatus and experimental data were analyzed based on the one-dimension Darcy’s law.Results showed that at a given pressure,the impregnation rate is inversely proportional to melt viscosity and jute fiber mat has higher porosity than glass fiber mat.The architecture,compressibility,permeability and fiber diameter of jute fiber mat were compared with those of glass fiber mat and their effects on impregnation were discussed further.It could be seen that the average diameter of jute fiber is much bigger;the porosity of jute fiber mat is significantly higher and inner bundle impregnation does not exist in jute fiber mat.Therefore,it is not difficult to understand why the impregnation rate in jute fiber mat is 3.5 times higher and permeability is 14 times greater.Kozeny constants of jute and glass fiber mats calculated based on the capillary model are 2950 and 442,respectively.

热塑性树脂浸渍黄麻纤维毡的研究

研究了热塑性树脂PP(聚丙烯)浸渍黄麻纤维毡的速率及相关因素,以解决天然纤维毡增强热塑性复合材料中连续熔融浸渍,考察了浸渍速率、温度等参数对其加工成型及力学性能的影响。用改装的毛细管流变仪作为实验装置,以一维Darcy定律处理实验数据,研究了压力对毡体空隙率以及熔体粘度对浸渍速率的影响。结果显示,相同的压力下,浸渍速率和熔体粘度成反比,麻纤维毡的压缩空隙率都要高于玻璃纤维毡。通过对纤维毡体结构、可压缩性、纤维直径以及毡体渗透率进行对比,进一步讨论了纤维毡浸渍速率的影响因素。表明麻纤维平均直径远大于玻璃纤维,纤维堆叠产生的空隙明显大于玻璃纤维且在麻纤维毡中不存在玻璃纤维毡中的束内浸渍,麻毡的浸渍速率约为玻纤毡的3.5倍,平均渗透率K约为玻纤毡的14倍。运用毛细管模型计算了两种毡体的Kozeny常数,其值分别为2950和442。

黄麻纤维毡的表面处理及其增强复合材料的力学性能

用3种不同的化学处理剂,碱、KMnO4和A-151硅烷偶联剂分别对黄麻纤维针刺毡表面进行处理,采用真空辅助树脂传递模塑法制备黄麻纤维毡增强乙烯基酯树脂复合材料。借助动态接触角分析了黄麻纤维的表面能变化,并通过SEM观察了纤维表面和复合材料的拉伸断裂面。研究结果表明:经表面处理后,黄麻纤维表面能有所降低,纤维表面的微观结构发生变化,纤维与树脂的界面相容性得到改善,综合力学性能提高。经A-151硅烷偶联剂处理后,复合材料的力学性能提高最为显著,拉伸强度和弯曲强度分别提高了51.38%和77.46%。

黄麻纤维毡增强复合材料的力学性能研究

文章对黄麻纤维进行表面处理,并制作纯黄麻纤维以及与碳纤维混杂的针刺毡;采用真空辅助树脂传递模塑法制备黄麻纤维毡增强乙烯基树脂复合材料,并测试其力学性能。结果表明:碱处理和双氧水处理后黄麻纤维表面杂质被去除,复合材料的界面性能得到改善,综合力学性能得到提高;黄麻/碳纤维混杂增强复合材料的拉伸性能提高更为显著,拉伸强度和拉伸模量比未处理纤维毡增强复合材料分别增加了146.2%和43.6%,但其弯曲性能却低于其他两种处理后的黄麻增强复合材料。

黄麻/碳混杂增强复合材料力学性能的理论预测与测试

采用碳纤维单向铺层于黄麻纤维针刺毡中,并制作相同纤维体积含量的黄麻纤维针刺毡,通过真空辅助树脂传递法分别制备了黄麻/碳混杂针刺毡、黄麻针刺毡、单向碳纤维毡增强乙烯基酯树脂复合材料,建立了黄麻/碳单向混杂增强复合材料拉伸与弯曲的数学模型,进行理论与实测值的比较,并分析了复合材料的力学性能。结果表明:黄麻/碳混杂增强复合材料力学性能的理论值与实测值存在一定的吻合性,在实际工程应用中可通过预测来制定混杂纤维针刺毡中黄麻纤维与碳纤维的混用比;单向碳纤维的加入有效地提高了复合材料的拉伸性能,复合材料的拉伸强度和拉伸模量比未加入碳纤维之前分别提高了107.20%和30.99%,但复合材料的弯曲模式没有太大的改变。