Samyn Pieter, Vonck Leo, Stanssens Dirk, Abbeele Henk Van den
Faculty for Environment and Natural Resources, Chair for Bio-Based Materials Engineering, University of Freiburg, 79085 Freiburg, Germany.
Topchim N.V., 2160 Wommelgem, Belgium.
J Nanosci Nanotechnol. 2018 May 1;18(5):3639-3653. doi: 10.1166/jnn.2018.14671.
The encapsulation of vegetable oils within an aqueous dispersion of polymer nanoparticles provides an alternative route to create functional paper coatings from renewable resources, by combining the presentation of hydrophobic moieties together with variations in roughness at the paper surface. The effects of two selected vegetable oil types, i.e., castor oil and hydrogenated castor oil (wax), are compared in terms of nanoparticle synthesis, coating hydrophobicity and surface gloss. The nanoparticles were synthesized by adding 50 wt.-% oil during imidization of poly(styrene-co-maleic anhydride) with ammonium hydroxide. From evaluation of the thermal properties, the nanoparticles have a high glass transition temperature that is suppressed in presence of oil. The nanoparticles with hydrogenated castor oil have higher imide content and better thermal stability compared to castor oil, in parallel with lower chemical reactivity of the hydrogenated oil and less interference with the imidization reaction. After deposition as a coating on paper, the physical coating properties are discussed in parallel with the coating chemistry and morphology or roughness at different scale lengths. The nanoparticle coatings with hydrogenated oil provides a multi-scale roughness with an open, porous nanoparticles structures and presentation of some amount free oil augmenting hydrophobicity towards a water contact angle of 128° (static contact angle) or 138° (advancing contact angle). The differences in surface coverage of coated papers in terms of imide and oil contents are confirmed by chemical Raman mapping. The differences in surface roughness are confirmed by non-contact profilometry, laser interferometry and atomic force microscopy.
将植物油封装在聚合物纳米颗粒的水分散体中，通过将疏水部分的呈现与纸张表面粗糙度的变化相结合，为从可再生资源制备功能性纸张涂层提供了一条替代途径。比较了两种选定植物油（即蓖麻油和氢化蓖麻油（蜡））在纳米颗粒合成、涂层疏水性和表面光泽方面的影响。纳米颗粒是在聚（苯乙烯 - 马来酸酐）与氢氧化铵酰亚胺化过程中加入50 wt.-%的油合成的。通过对热性能的评估，纳米颗粒具有高玻璃化转变温度，在油存在下该温度会受到抑制。与蓖麻油相比，含氢化蓖麻油的纳米颗粒具有更高的酰亚胺含量和更好的热稳定性，同时氢化油的化学反应性较低，对酰亚胺化反应的干扰较小。作为涂层沉积在纸张上后，结合涂层化学以及不同尺度长度下的形态或粗糙度来讨论物理涂层性能。含氢化油的纳米颗粒涂层具有多尺度粗糙度，具有开放的多孔纳米颗粒结构，并且一定量游离油的存在使水接触角增大至128°（静态接触角）或138°（前进接触角）。通过化学拉曼映射证实了涂布纸在酰亚胺和油含量方面表面覆盖率的差异。通过非接触轮廓仪、激光干涉仪和原子力显微镜证实了表面粗糙度的差异。
