Preparation of wood powder/polypropylene composites in presence of subcritical fluids
-
摘要: 提出了一种通过亚临界流体辅助反应挤出制备木粉/聚丙烯（PP）复合材料的新型制备方法，其关键是在挤出过程中引入流体（乙醇和正丙醇），并使流体处于亚临界状态。同时，对木粉/PP复合材料进行了力学性能测试、FTIR和SEM观察。结果表明：在亚临界流体辅助反应挤出中，木粉发生了溶胀、液化等，有利于马来酸酐接枝聚丙烯渗入到木粉内部，其中酸酐基团与木粉中含有的大量羟基发生酯化反应增强，从而提高了木粉/PP复合材料的界面结合。在亚临界乙醇（190℃，（2.4±0.1） MPa，120 r/min）作用下制备的木粉/PP复合材料的力学性能（拉伸强度、弯曲强度、弯曲模量和无缺口冲击强度）与无流体时制备的木粉/PP复合材料相比，其性能得到了一定的提高，它们分别达到了23.5 MPa、52.5 MPa、4.8 GPa和5.9 kJ · m-2。Abstract: A new method has been applied to prepare the wood powder/polypropylene (PP) composites. The key procedure is to inject fluids (ethanol and propanol) during extrusion process and to make the fluid in the subcritical state at a certain temperature. Furthermore, the structures of wood powder/polypropylene composites were analyzed and observed by FTIR, SEM. Due to the hydrophilic nature, there are a large number of hydroxyls in wood powder, which can esterify with maleic anhydride grafted polypropylene (PP-g-MAH). The results show that the subcritical fluid as a swelling agent and reaction medium promotes the interfacial reaction between wood powder and PP-g-MAH, which leads to the improvement of the interface bond strength. When ethanol is at subcritical state (190℃, (2.4±0.1)MPa, 120 r/min), ethanol as a reaction media is helpful to swelling and liquefaction of wood powder. Subcritical ethanol can further promote the esterification between wood powder and PP-g-MAH as well as the dispersibility of wood powder in PP matrix. In addition, wood powder can be permeated by PP-g-MAH under the high temperature and pressure, the interfacial reaction is strengthened. The tensile strength, flexural strength, flexural modulus and non-notched impact strength of the wood powder/polypropylene composites at the reaction condition in subcritical ethanol reach 23.5 MPa, 52.5 MPa, 4.8 GPa, and 5.9 kJ · m-2, respectively, comparing with wood powder/PP composites without fluids during extrusion procession.
-
-
计量
- 文章访问数: 969
- HTML全文浏览量: 52
- PDF下载量: 872
下载:
