协同表面处理下聚乙烯木塑复合材料的胶结机理及其胶接耐久失效行为研究

Wood-polyethylene composites are widely used in many fields for its excellent properties with double advantages of wood and plastics, but they are hard to adhere for the polythene ingredient with low surface energy within the composites, which resulted in the poor durability for the bonded joint. In order to achieve the adhere connection of wood-polyethylene composites as well as the good durability for the bonded joint, the synergistic surface treatment of coupling agent surface coating and plasma discharge was used to treat the surface for the composites. And the effect of the synergistic effects of surface coating with various coupling agent and plasma discharge with air atmosphere on the surface properties, adhesive strength and the durability for the bonded joint in various using environment were studied by the analysis of contact angle, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) and the test for adhesive strength. Combined with the characterization of the destruction type and breaking mechanism for the bonded joint, the bonding mechanism and the behavior of adhesion endurance failure for wood-polyethylene composites based on novel synergetic surface treatment was also explored. The study for the project would helpful to establish the technique of rapid surface treatment and bonding of the wood-polyethylene composites, and the above research would also provide the scientific basis and practical methods for achieving the seamless connection of wood-polyolefin composites by cementing and expanding the application domain of wood-polyolefin composites.

聚乙烯木塑复合材料兼具木材和塑料的双重优点，在许多领域得到了广泛应用。然而其中低表面能的聚乙烯成分，导致木塑复合材料难以实现以胶接进行的无缝连接，且胶接耐久性差。为实现聚乙烯木塑复合材料具有良好胶接耐久性的胶接连接，采用偶联剂涂覆与等离子体放电相结合的协同表面处理技术对聚乙烯木塑复合材料进行表面处理，通过胶接性能测试并结合表面接触角分析、红外光谱分析、XPS光电能谱分析以及表面形貌观测等微观分析方法，研究不同偶联剂表面涂覆处理与空气气氛下等离子体处理的协同作用对聚乙烯木塑复合材料表面性质、胶接强度以及不同使用环境下胶接耐久性能的影响，结合胶接接头破坏类型及破坏机制的表征，探究协同表面处理下聚乙烯木塑复合材料的胶接机理及其胶接接头的耐久失效行为，建立聚乙烯木塑复合材料的快速表面处理与胶接连接技术，为实现聚烯烃基木塑复合制品的无缝连接，扩大其应用范围而提供科学依据和切实可行的方法。

聚乙烯木塑复合材料（PE-WPC）兼具木材和塑料的双重优点，在许多领域得到了广泛应用。然而其中低表面能的聚乙烯成分，导致PE-WPC难以实现以胶接进行的无缝连接，限制了其应用的扩展。为此，项目研究围绕PE-WPC的表面处理与胶接而展开，通过表面处理前后PE-WPC表面性质、胶接强度以及胶接耐久性能的表征，系统研究了偶联剂涂覆和射流等离子体放电等单一表面处理方法以及将偶联剂涂覆与射流等离子体放电相结合的协同表面处理方法对PE-WPC表面性质和胶接行为的影响。.使用环氧树脂做胶黏剂，未处理的PE-WPC胶接强度仅为1.34MPa；打磨处理后，胶接强度为4.28MPa，相比未处理试样明显提高；射流等离子体处理后，胶接强度增至10.83MPa；硅烷偶联剂涂覆处理后，胶接强度为11.13MPa；而经硅烷偶联剂涂覆和等离子体放电协同处理后，其胶接强度可达16.61MPa，分别比打磨处理、等离子体处理和偶联剂涂覆处理提高了171.26%、53.37% 和49.24%，体现了表面处理的协同作用效果。胶接接头的破坏形式也由未处理试样的界面破坏、单一表面处理试样的混合破坏向协同表面处理试样的材料本体破坏转变。.众多影响胶接接头耐久性的使用环境中，水环境影响最大。随着水环境下使用时间的延长，不论采用哪种方法处理，PE-WPC胶接接头的强度均会下降。相比之下，协同表面处理的胶接试样强度下降幅度最小，尤其是在沸水中浸泡300h后，胶接强度仍可达到5.59MPa，保持率达到33.65%，显示出良好的水环境耐久性。.协同表面处理既能在PE-WPC表面引入极性含氧基团，又能通过偶联剂与PE-WPC中木质成分之间的化学键连接减少了亲水羟基的数量，增加了胶接界面抵御外界环境破坏的能力，从而保证了胶接接头的胶接强度和胶接耐久性能。 .采用聚氨酯热熔胶做胶黏剂，利用多异氰酸酯涂覆和等离子体放电协同处理PE-WPC，相比打磨处理和单一多异氰酸酯涂覆处理，协同处理后其胶接强度分别提高了122.64%和28.26%，水环境下浸泡200h后的胶接强度保持率为46.73%，从而可以实现聚乙烯木塑复合材料具有良好胶接强度和耐久性能的快速表面处理与快速胶接，为实现聚烯烃基木塑复合制品的无缝连接，扩大其应用范围提供了科学依据和切实可行的方法。