Surface modification and lamination of polymers by photografting
Surface modification and lamination of polymers by photografting
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DOI：
10.1016/s0143-7496(98)00066-9
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发表时间：
1999-10-01
影响因子：
3.4
通讯作者：
Rånby, B
中科院分区：
文献类型：
--
作者：
Rånby, B
本文介绍了紫外光引发聚合物表面光接枝的实验过程：引发剂和单体气相转移的间歇过程和引发剂和单体在基底表面薄层溶液中液相转移的连续过程。接枝效率约为80%，所得接枝层非常薄（小于10 nm）。本文讨论了“表面光接枝”的机理，认为是由于引发剂二苯甲酮（BP）吸收远紫外光（约250 nm）激发到S-2态，并跃迁到“过热”的“BPS”态，将多余的能量转移到基底表面的CH基团上，形成BP三重态（T-1和T-2）。激发的CH基团和BPT 1和BPT 2状态通过夺氢反应并在衬底表面形成自由基。这些自由基将单体添加到接枝链中。“表面光接枝”是作为塑料薄膜的“光引发层压”方法而开发的。通过紫外光照射，在两层膜之间接枝一薄层引发剂和单体。形成短的线性接枝链，其通过连续的UV照射生长为支链，其最终填充两个基底膜之间的空间。链端通过加成来自二苯甲酮的酮基而终止。一些增长的链端可以通过自由基结合而终止。通过加入少量的多官能团单体，形成网络，该网络通过主价键接枝到两个膜表面。“本体表面光接枝”使层合物具有高机械强度。当功能膜接枝在两个载体膜之间时，形成具有选定的和高阻隔性能的层压材料，其对于作为包装材料的应用是有意义的。(C)1999爱思唯尔科技有限公司。保留所有权利。
This paper describes experimental processes for UV initiated "surface photografting" of polymers: the batch process with vapor-phase transfer of initiator and monomer and the continuous process with liquid-phase transfer of initiator and monomer in a thin layer of solution on the surface of the substrate. The grafting effiency is about 80% and the resulting grafted layers are very thin (less than 10 nm). The mechanism of "surface photografting" is discussed and proposed to be based on excitation of benzophenone (BP) as initiator to an S-2 state by absorption of far UV irradiation (approximate to 250 nm) and transition to a "superheated" "BPS," state, which transfers its excess energy to CH groups at the substrate surface and forms BP triplet states (T-1 and T-2). The excited CH groups and the BPT1 and BPT2 states react by hydrogen abstraction and form radicals at the substrate surface. These radicals add monomer to grafted chains. "Surface photografting" is developed as a method for "photoinitiated lamination" of plastic films. A thin layer of initiator and monomer between two films is grafted to the two him surfaces by UV irradiation. Short linear grafted chains are formed which by continued UV-irradiation grow to branched chains which eventually fill the space between the two substrate films. The chain ends are terminated by addition of ketyl radicals from the benzophenone. Some growing chain ends may terminate by radical combination. With addition of a small amount of a multifunctional monomer, a network is formed which is grafted to the two film surfaces by main valence bonds. The "bulk surface photografting" gives laminate of high mechanical strength. When a functional film is grafted between two carrier films, laminates of selected and high barrier properties are formed which are of interest for application as packageing materials. (C) 1999 Elsevier Science Ltd. All rights reserved.