改性聚脲涂料的制备及其在发泡聚丙烯中的应用

Preparation and Performance of Modified Polyurea Coatings for Surface Coating of EPP Products

摘要:

涂层能够提高发泡聚丙烯（EPP）制品的表面强度，延长其使用使命。然而，对于未经表面改性EPP材料，开发具有高附着力的涂层仍是一个挑战。本文以氨化聚丙烯（PP-g-NH2）为改性剂和交联剂，采用预聚体法将亲水单体二羟甲基丙酸（DMPA）引入聚脲分子链制备了PP-g-NH2改性水性聚脲（WPUA），改善了聚脲涂料对EPP基体粘结性差的问题。傅里叶变换红外光谱（FT-IR）表明PP-g-NH2被成功地引入到WPUA的分子链中。研究PP-g-NH2含量(PP-g-NH2质量占改性WPUA原料总质量的百分比，下同)对WPUA的粘附力、接触角、耐溶剂性、机械性能和热稳定性的影响。结果表明：当PP-g-NH2含量达到1.5%时，涂膜性能最佳，吸水率及接触角达到14.52%、84.85°，优于EPP性能；拉伸强度和断裂伸长率分别为30.6 MPa、233.7%；热分解温度提高20 ℃，对EPP的附着力达到0.89MPa，相比未改性聚脲提升65%。

Abstract:

The surface strength of expanded polypropylene (EPP) products can be improved and their service life extended through the application of coatings. However, developing coatings with high adhesion to unmodified EPP materials remains a challenge. In this study, polypropylene-grafted-amine (PP-g-NH2) was used as a modifier and crosslinking agent, and a waterborne polyurea (WPUA) was prepared by introducing hydrophilic monomer dimethylolpropionic acid (DMPA) into the polyurea molecular chain using a prepolymer method. The aim was to improve the poor adhesion of the polyurea coating to the foamed polypropylene (EPP) substrate. Fourier transform infrared spectroscopy (FT-IR) confirmed the successful incorporation of PP-g-NH2 into the WPUA molecular chain.The effect of PP-g-NH2 content (mass percentage of PP-g-NH2 relative to the total mass of modified WPUA raw materials) on the adhesion, contact angle, solvent resistance, mechanical properties, and thermal stability of WPUA was investigated. The study found that introducing a 1.5% mass fraction of PP-g-NH2 into the system resulted in enhanced membrane properties. The modified membranes exhibited a water absorption capacity of 14.52% and a contact angle of 84.85°, outperforming unmodified EPP. Additionally, the modified membranes showed improved tensile strength (30.6 MPa) and elongation at breakage (233.7%). Furthermore, the thermal decomposition temperature of the modified membranes increased by 20℃and the adhesion to EPP reached 0.89 MPa, representing a 65% improvement compared to unmodified polyurea.