生物可分解聚乳酸(PLA)係由可再生之資源聚合而成，聚乳酸是一種直鏈脂肪族的熱塑性聚酯?(aliphatic polyester)，使用後可由自然界之細菌、黴菌、藻?等微生物的作用，能逐漸分解成二氧化碳與水，?會對生活環境造成衝擊。而聚乳酸已經與多?之?同成分化合物結合，如?米添加劑，增韌劑，阻燃劑，可塑劑，及其他高分子等，藉以改進聚乳酸物性，特別在電子產業，?經常需要抗靜電或抗電磁幅射之低阻抗聚乳酸複材。本研究將基於上一期計畫之成果，已成功製備膨脹石墨聚丙烯?米複材，因此本計畫將針對石墨片直接進?氧化還原改質，以化學方法製備有機化石墨烯，並以融熔混?法製備石墨烯填充聚乳酸?米複材。而主要目的在探討改質後之?米石墨烯，能否均勻分散於高分子基材中，因為分散性對增進複材的傳導及機械等性質，有決定性的影響。分散均勻的複合材?，可以將其視為一?續體，在承受形變時添加劑及其界面能夠吸收部份應?，進而提升複材的物性及機械性質。然而添加劑的分散?況除?取決於添加劑本身的物性以及藉表面處?改善和基材間的界面性質，亦需要藉由混?設備?達到均勻混?的目的，增強複材的物性。本計畫將製備熱塑性高分子材?聚乳酸/石墨烯之?米複合材?，以馬?酐接枝聚乳酸(PLAgMA)為相容劑，分別探討?同配方之複材，使用塑譜儀雙?桿等熔融混?方式製備實驗試片，探討石墨烯之分散均勻性，及其與機械性質、導熱性質與導電性質的關?性。而本計畫在一?內分成?階段進?，第一階段為石墨片之氧化還原及層插改質，以化學方法有機化石墨烯，並檢定無機石墨烯處?前後之結構及其表面性質變化，另外亦以融熔方式進?聚乳酸接枝及胺化反應。第二階段以融熔混?法製備聚乳酸/石墨烯之?米複材，決定塑譜儀基本之操作條件與混?分散之觀察，並決定?同條件對混?機構之影響，同時研究?同相容劑對複材內黏土分散之影響，並檢定複材樣品及其?變、導熱、與介電及導電等性質。 Polylactide (PLA), a renewable, sustainable, biodegradable, and eco-friendly thermoplastic polyester, is of increasing interest from industry and academia, because it has attractive properties comparable with petroleum-based polyolefins. Therefore, PLA is currently considered as a promising polymer for various end-use applications. In some cases, a low electrical resistivity of PLA is required for the electrostatic and/or electromagnetic dissipation of advanced applications. The current project will be based on the previous research results, where we have successfully prepared the polypropylene/expanded graphite nanocomposites. The major goal is to modify the graphite stacks through oxidation and reduction; and the chemical treatment instead of thermal shock expansion is employed to produce organically modified graphene. The modified graphene will be used to prepare the polylactide/graphene nanocomposite via melt blending. The main theme is to study the dispersion degree of nanographene in the polymer matrix, which is of paramount importance in improving the conductive and mechanical properties of composites. Composites with good dispersion can be deemed as a continuum such that the filler and the interphase can absorb part of the stress due to external load, and hence enhance the physical properties. The dispersion of filler depends on the particle characteristics and the surface treatment which may change the interfacial properties between filler and matrix. The compounding procedure is also important in determining the dispersion of filler. There are many kinds of compounding machines. The plasticorder internal compounder can operate under different conditions for compounding different composite systems according to either the distributive mechanism or the dispersive mechanism. Therefore such machine has the great flexibility. The research plan will be conducted in two stages within one year. The first stage will be the oxidation and reduction of graphite oxide with a suitable intercalant, and the preparation of maleic anhydride grafted PLA via reactive b lending. The second stage will prepare the polylactide/graphene nanocomposite via melt blending with optimum operating conditions. The influence of compatibilizers will be studied. The rheological properties, the thermal and the dielectric behaviors will also be investigated.
