以高分子分散劑作為奈米粉體濕式分散研磨、界面改質及合成的研究

Abstract

高分子分散劑，具有一錨接基（anchoring group）與一樹脂相容鏈（binder compatible chain），可應用於奈米粒子之濕式分散與界面改質。本研究實驗結果證實，利用此分散劑亦可形成一微乳液系統，並用以合成奈米粒子。 本研究據此特性，首先對奈米ZnO粒子作濕式分散研究，並完成了30wt%固含量的水性奈米ZnO漿料的分散，其粒徑分佈D(90)=130nm，穩定期已達三年之久。另以含分散劑之水溶液，合成奈米氧化鐵（magnetite），此氧化鐵具獨立（isolated）分散與超順磁之特性，且由於經過界面修飾，因此可以直接加樹脂而合成塗料，作為抗紫外線塗層之用；以及作為ELISA(酵素免疫分析法，Enzyme-linked immunoassay)生化檢驗之磁性載體（奈米免疫磁珠）之用。此外，本法亦適用於奈米銀之合成。 本研究亦利用奈米ZnO分散液及奈米銀，加入PU後形成抗菌漿料。經SGS實驗證實，抗菌效果相當好，此主要歸因於優異的分散性，所產生巨大的反應比表面積。另亦針對TiO2光觸媒作濕式分散，之後進行超親水之研究。實驗結果顯示，由於均勻的分散，使PET光觸媒塗層具高的穿透度（86%），以及極佳的超親水性（接觸角為3度）。 因此，利用高分子分散劑，不僅可以分散奈米粒子，亦可以形成微乳液系統，進而合成具表面修飾的奈米粒子。此法的優點為簡便、經濟，且具產品實用性。

Polymeric dispersants that comprise of an anchoring group and a binder-compatible chain, exhibiting steric hindrance, can be used in the wet grinding, dispersing and surface modification of nano-sized particles. Polymeric dispersant can also form a microemulsion system and nano-sized particles then synthesized. This work studies the dispersion of nano-sized ZnO in water. Wet dispersion with an appropriate amount of dispersant yields a good suspension with concentrated fill with a high solid content （30wt%）. The particle size distribution is given by D(90)=127nm and the suspension herein has remained stable for at least three years. Nano-sized magnetite particles were synthesized from a low-concentration solution of dispersant, which was identified as a microemulsion system by evaluating the surface tension and particle size distribution, indicating that the magnetite nanoparticles not only had an isolated suspension state and exhibited superparamagnetic behavior, but also achieved surface modification. Surface modification enables an anti-UV coating to be formed by the direct addition of PU resin. The magnetite nanoparticles can also be the immuno-magnetic beads if coated with COOH functional groups, becoming ELISA（enzyme-linked immunoassay）carriers. The sensitivity in Hp antibody detection is similar to that of expensive commercially available immuno-magnetic beads, called Dynabeads M450. Furthermore, this low-concentration dispersant solution can be used to prepare stable colloidal nano-sized silver. The antibacterial property of nano-sized ZnO and silver was evaluated. Antiseptic was made by mixing a suitable amount with PU and these two colloids. The rate of reduction of bacteria by this antiseptic was excellent, because of the good suspension of these nano-sized particles, resulting in a large reactive surface area. The superhydrophilic characteristic of nano-TiO2 was also investigated. Wet dispersion yielded a good suspension of TiO2, which coated the PET film. Its transmittance in the visible region was high and it exhibited superhydrophilicity （with a contact angle of 3 degree） because of the quality of the suspension. In summary, a dispersant can’t be used only to obtain a good suspension of nanoparticles（top down） but also to prepare nanometer- scale particles（bottom up）.