Vapor phase infiltration of zinc oxide into thin films of cis -polyisoprene rubber
Vapor phase infiltration of zinc oxide into thin films of cis -polyisoprene rubber
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氧化锌气相渗透顺式聚异戊二烯橡胶薄膜
DOI：
10.1039/d0ma00304b
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发表时间：
2020
影响因子：
5
通讯作者：
Losego, Mark D.
中科院分区：
文献类型：
--
作者：
Pilz, Julian;Coclite, Anna Maria;Losego, Mark D.
弹性体是一类重要的聚合物，具有多种用途。通常，在弹性体的聚合物基质中添加添加剂以促进硫化或增强物理或化学性能。本研究采用气相渗透法将天然橡胶中未硫化的顺式聚异戊二烯转化为有机/无机杂化材料。具体地说，我们研究了二乙基锌(DEZ)和水的单循环渗透形成渗透的氧化锌物种。有趣的是，顺式聚异戊二烯的低温预热对渗透过程有很大的影响，包括扩散系数、最大溶解度和化学反应活性。我们将这些效应归因于薄膜松弛和氧化的共同作用。与热处理无关，所有渗透过程都显示出一致的氧化锌负载，而与DEZ和水剂量之间的清洗时间无关，这表明在DEZ前体和顺式聚异戊二烯聚合物之间存在强结合的中间态。根据Fick定律和气相吸附平衡，提高浸渗过程温度加速了扩散，降低了最大溶解度。得到的有机-无机杂化薄膜在甲苯中表现出更强的耐溶性能，甲苯是纯聚合物的良好溶剂。
Elastomers are an important class of polymers for many applications. Often, additives are added to the polymer matrix of elastomers to promote vulcanization or enhance physical or chemical properties. In this study, vapor phase infiltration (VPI) is investigated for transforming unvulcanized cis-polyisoprene (from natural rubber) into an organic/inorganic hybrid material. Specifically, we examine single-cycle infiltration with diethylzinc (DEZ) and water to form infiltrated zinc oxide species. Interestingly, low-temperature pre-heating of the cis-polyisoprene acutely affects the processes of infiltration, including diffusivity, maximum solubility, and chemical reactivity. We attribute these effects to a combination of film relaxation and oxidation. Independent of thermal pre-treatments, all infiltration processes exhibited consistent zinc oxide loading irrespective of purge time between the DEZ and water doses, indicating the presence of a strongly bound intermediate state between the DEZ precursor and the cis-polyisoprene polymer. Increasing infiltration process temperature accelerates diffusion and lowers the maximum solubility, in accordance with Fick's law and gas phase sorption equilibrium. Resulting organic–inorganic hybrid films show enhanced resistance to dissolution in toluene, a good solvent for the pure polymer.