低温氮等离子体对聚乳酸薄膜表面性能的改性  

Effect of Low-Temperature N2 Plasma Modification on the Performance of Polylactic Acid Films

作　　者：李茹[1] 杨鑫 高文静 刘乃毓 邢倩云 Ru Li;Xin Yang;Wenjing Gao;Naiyu Liu;Qianyun Xing(School of Environmental and Chemical Engineering,Xi'an Polytechnic University,Xi'an 710600,China)

机构地区：[1]西安工程大学环境与化学工程学院,陕西西安710600

出　　处：《高分子材料科学与工程》2023年第7期75-84,共10页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(11105102);陕西省科技总体创新工程计划(2011KTCL01-12)。

摘　　要：文中利用朗缪尔探针对低温氮(N2)等离子体进行了诊断,探究了电子密度随射频功率、压强、轴线距离的变化情况。利用水接触角表征了右旋聚乳酸(PDLA)改性前后亲水性变化,探究了改性PDLA膜的最佳条件。利用原子力显微镜、X射线衍射、热重分析仪、X射线光电子能谱表征了改性前后PDLA膜的表面形貌、晶体结构、热稳定性能及表面元素的变化。通过测量拉伸强度、断裂伸长率、透光率表征了改性前后PDLA膜力学性能、阻隔性能的变化。结果表明,在最佳条件下(射频功率100W、压强25Pa、改性时间180s、轴向距离10cm),PDLA膜的接触角从89.53°下降至49.96°;改性后PDLA膜的力学性能略有降低,在放电中心处拉伸强度和断裂伸长率比原膜分别降低了26.31%(横向)、24.41%(纵向)和29.41%(横向)、28.1%(纵向);热稳定性能较原膜略有增加,阻隔性能基本保持不变;随着储存时间的延长,PDLA膜的接触角不断增加,当存储30d时,样品仍保留了部分改善的亲水性。The low temperature nitrogen(N2)plasma was diagnosed using Langmuir probe to explore the variation of electron density with RF power,pressure and axial distance.The water contact angle was used to characterize the change of hydrophilicity before and after modification and to explore the optimal conditions for modified D-polylactic acid(PDLA)films.The changes in surface morphology,crystal structure,thermal stability properties and surface elements of PDLA films before and after modification were characterized through scanning electron microscopy(SEM),X-ray diffraction(XRD),thermogravimetric analysis(TGA)and X-ray photoelectron spectroscopy(XPS).The changes of mechanical properties and barrier properties of PDLA films before and after modification were characterized by measuring tensile strength,elongation at break and light transmission rate.The experimental results show that the contact angle of PDLA film is decreased from 89.53°to 49.96°under the optimal conditions(RF power 100 W,pressure 25 Pa,modification time 180 s,axial distance 10 cm);the mechanical properties of PDLA film are decreased slightly after modification,and the tensile strength and elongation at break at the center of discharge are decreased by 26.31%(transverse)24.41%(longitudinal)and 29.41%(transverse)28.1%(longitudinal);the thermal stability increases slightly compared with the original film,and the barrier properties remain basically unchanged;the contact angle of PDLA film is increased continuously with the increase of storage time.When stored for 30 d,the samples all still retain some of their improved hydrophilicity.

关 键 词：低温等离子体 聚乳酸 亲水性能 力学性能 

分 类 号：TQ323.4[化学工程—合成树脂塑料工业]