title: Cross-Linking Poly(lactic acid) Film Surface by Neutral Hyperthermal Hydrogen Molecule Bombardment.
abstract: Constructing a dense cross-linking layer on a polymer film surface is a good way to improve the water resistance of poly(lactic acid) (PLA). However, conventional plasma treatments have failed to achieve the aim as a result of the unavoidable surface damage arising from the charged species caused by the uncontrolled high energy coming from colliding ions and electrons. In this work, we report a modified plasma method called hyperthermal hydrogen-induced cross-linking (HHIC) technology to construct a dense cross-linking layer on PLA film surfaces. This method produces energy-controlled neutral hyperthermal hydrogen, which selectively cleaves C-H bonds by molecule collision from the PLA film without breaking other bonds (e.g., C-C bonds in the polymer backbone), and results in subsequent cross-linking of the carbon radicals generated from the organic molecules. The formation of a dense cross-linking layer can serve as a barrier layer to significantly improve both the hydrophobicity and water vapor barrier property of the PLA film. Because of the advantage of selective cleavage of C-H bonds by HHIC treatment, the original physical properties (e.g., mechanical strength and light transmittance) of the PLA films are well-preserved.
authors.affiliation: Faculty of Materials Science and Engineering, Kunming University of Science and Technology , Kunming, Yunnan 650093, People's Republic of China.
authors.forename: Wangli
authors.initials: W
authors.lastname: Du
authors.affiliation: Chengdu Green Energy and Green Manufacturing Technology R&D Center, Chengdu Development Center of Science and Technology, China Academy of Engineering Physics , Chengdu, Sichuan 610207, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Shao
authors.affiliation: Chengdu Green Energy and Green Manufacturing Technology R&D Center, Chengdu Development Center of Science and Technology, China Academy of Engineering Physics , Chengdu, Sichuan 610207, People's Republic of China.
authors.forename: Zhoukun
authors.initials: Z
authors.lastname: He
authors.affiliation: Chengdu Green Energy and Green Manufacturing Technology R&D Center, Chengdu Development Center of Science and Technology, China Academy of Engineering Physics , Chengdu, Sichuan 610207, People's Republic of China.
authors.forename: Changyu
authors.initials: C
authors.lastname: Tang
authors.affiliation: Chengdu Green Energy and Green Manufacturing Technology R&D Center, Chengdu Development Center of Science and Technology, China Academy of Engineering Physics , Chengdu, Sichuan 610207, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Faculty of Materials Science and Engineering, Kunming University of Science and Technology , Kunming, Yunnan 650093, People's Republic of China.
authors.forename: Tao
authors.initials: T
authors.lastname: Shen
authors.affiliation: Faculty of Materials Science and Engineering, Kunming University of Science and Technology , Kunming, Yunnan 650093, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Chengdu Green Energy and Green Manufacturing Technology R&D Center, Chengdu Development Center of Science and Technology, China Academy of Engineering Physics , Chengdu, Sichuan 610207, People's Republic of China.
authors.forename: Woon-ming
authors.initials: WM
authors.lastname: Lau
authors.affiliation: Department of Mechanical Engineering, University of New Orleans , New Orleans, Louisiana 70148, United States.
authors.forename: David
authors.initials: D
authors.lastname: Hui
mesh_terms: D002244:Carbon / Q000737:chemistry; D055598:Chemical Phenomena; D003432:Cross-Linking Reagents / Q000737:chemistry*; D018857:Food Packaging / Q000295:instrumentation; D006358:Hot Temperature; D006859:Hydrogen / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D019344:Lactic Acid / Q000737:chemistry*; D011091:Polyesters; D011108:Polymers / Q000737:chemistry*; D013227:Steam; D013499:Surface Properties
chemical_list: D003432:Cross-Linking Reagents; D011091:Polyesters; D011108:Polymers; D013227:Steam; D019344:Lactic Acid; C033616:poly(lactide); D002244:Carbon; D006859:Hydrogen
keywords: hydrophobicity; hyperthermal hydrogen; polylactic acid; surface cross-linking; water vapor barrier property