不同紫外波长对热塑性淀粉塑料表面的光交联改性研究

为有效提高热塑性淀粉塑料（TPS）的力学和耐水性能，本文提出用不同波长的紫外光照的方法来实现TPS表面的光交联改性。将光引发剂2,4,6?三甲基苯甲酰基二苯基氧化膦（TPO）的乙醇溶液涂覆于TPS表面后进行紫外光照射，研究了不同紫外光波长（254、308、365 nm）对TPS交联度、力学性能、动态力学性能、耐水性和吸湿性的影响。结果表明，与254 nm和365 nm紫外光照后的样品相比，308 nm光照后TPS样品的拉伸、弯曲和冲击强度最大，分别为4.1 MPa，2.7 MPa和96.8 kJ/m²;TPS中淀粉富集区的玻璃化转变温度（T_α）、甘油富集区的玻璃化转变温度（T_β）分别达最高为-37.48 ℃和50.32 ℃，表面接触角最大为75 °，吸水性能也得到显著改善，交联度结果证实此时形成了最佳的交联结构。

Study on Surface Modification of Thermoplastic Starch Plastics through Photo?crosslinking at Different Ultraviolet Wavelengths

To improve the mechanical and water?resistant properties of thermoplastic starch plastics (TPS), a photo?crosslinking modification was conducted on the surface of TPS with 2,4,6?trimethylbenzoyldiphenyl phosphine oxide as a photoinitiator under the ultraviolet (UV) irradiation at different wavelengths. The effect of UV wavelength on the cross?linking degree, stretching performance, dynamic mechanic properties and water?resistance of modified TPS was investigated. The results indicated that the modified TPS achieved the maximum tensile strength of 4.1 MPa, flexural strength of 2.7 MPa, and impact strength of 96.8 kJ/m². The modified TPS exhibited two glass transition temperatures at -37.48 and 50.32 °C in the starch and glycerol domains, respectively. Moreover, a maximum contact angle of 75 °C was obtained for the modified TPS, and their water resistance was improved remarkably. The characterization of cross?linking degree further confirmed that the TPS gained an optimum crosslinking structure.