以乳化聚合法合成高固含量之生質乳膠顆粒

Abstract

在近年來，全球碳排放和極端天氣等環境問題愈發嚴重，因此研究利用可再生的生物質材料替代石化產品變得非常重要。聚衣康酸（poly(itaconic acid)）因其單體衣康酸（itaconic acid）可通過木質纖維素植物發酵大規模生產而備受關注。在本研究中，我們採用簡單的一步驟乳液聚合方法合成了核殼型乳膠顆粒，並且成功利用硫酸鉀水性起始劑（KPS）以及市售非離子型反應型乳化劑（ER-10）來合成高固含量（50wt%）的乳液。在乾燥後的產品中，含有40wt%的聚衣康酸材料也足以用作綠色塗料。我們還發現，衣康酸可作為助乳化劑，協同促進高固體含量和生質核殼型奈米顆粒的合成。此研究還探討了乳化聚合的最適配方條件，包括起始劑用量和加入時間的影響，以及衣康酸用量對聚合轉化率的影響。 為了增加乳液的生質含量，在本研究中我們引入了高生質含量的單體，包括二丁基己烯二酸酯（DBIA）和月桂基丙烯酸酯（LA）。同時，我們發現添加反應性較強之甲基丙烯酸甲酯（MMA）及其用量是成功和呈穩定乳膠顆粒之關鍵。過多的MMA會導致反應過快且易固化，但因為生質單體DBIA的反應性較差，若是沒有反應性單體的加入，反應將無法聚合。在這項研究中，我們成功地合成了一種固含量為50wt%的乳液，其中生質含量超過50％，並使乳液顆粒呈現梯度結構。透過改變實驗方法，使得衣康酸（IA）與其他油相單體之間共聚合反應更加均勻，這樣的改變導致乳液內部形成梯度結構。總結來說，這項研究成功地利用引入DBIA和LA單體以及反應性單體MMA組分，配製出高生質含量和高固含量的乳液。

Recently, research into replacing petrochemicals with renewable biomass materials has gained tremendous importance due to growing environmental concerns such as global carbon emissions and extreme weather conditions. Poly(itaconic acid) (PIA) has therefore received a lot of attention because its monomer, itaconic acid (IA), is a renewable chemical and can be produced on a large scale by fermentation from lignocellulosic plants. In this study, we synthesize core/shell latex nanoparticles with PIA as the shell and petrochemical poly(methyl methacrylate)-co-poly(butyl acrylate) (poly(MMA/BA)) as the core using a simple one-pot emulsion polymerization method. A high total solids content of a 50 wt% emulsion solution suitable for commercial use and a high biomass content of 40 wt% PIA in the dried coated product sufficient to be used as green material can be achieved through the use of an aqueous initiator of potassium persulfate (KPS) and a commercially available nonionic reactive emulsifier of ER-10. IA was found to act as a co-emulsifier, synergistically facilitating the synthesis of the high solids and biomass core/shell nanoparticles. Advances in optimizing the emulsion synthesis process are also reported, including the effects of initiator level and timing, and IA level to improve polymerization conversion. The core/shell nanoparticles could prove useful in future coatings and the ion absorption industry. In an effort to pursue eco-friendly and greener products, the emulsion formulation was modified by introducing high biomass monomers. Specifically, dibutyl itaconate (DBIA) and lauryl acrylate (LA) were incorporated into the emulsion formulation as monomers with a high bio-based content. Alongside these additions, the amount of reactive monomer methyl methacrylate (MMA) was considered an essential comonomer for the study. Too much MMA will significantly increase the polymerization rate too fast to cause coagulation. However, the reaction cannot proceed without the reactive monomer of MMA due to the insufficient reactivity of DBIA monomer. The successful synthesis of a 50wt% emulsion was achieved, featuring both high solids content and a bio-based content exceeding 50%. Unlike petroleum-based emulsions that exhibit a distinct core-shell structure, the bio-based emulsions demonstrated a gradient structure poly(DBIA/LA/MMA/IA). This gradient structure emerged as a result of modifications in the experimental procedure, specifically the improved combination effect between itaconic acid (IA) and other oil phase monomers. This enhanced combination effect led to the formation of a gradient structure within the emulsion. Overall, this study highlights the successful formulation of a high bio-based content emulsion with a gradient structure, achieved through the introduction of DBIA and LA monomers alongside the essential MMA component.