以酸酐改性 PVA 泡棉物性的探討

Tunghai University Institutional Repository > 工學院 > 化學工程與材料工程學系所 > 碩博士論文 > Item 310901/30787

Please use this identifier to cite or link to this item: http://140.128.103.80:8080/handle/310901/30787

Title:	以酸酐改性 PVA 泡棉物性的探討
Other Titles:	Analysis the Physical Properties of Poly (vinyl alcohol) Foam grafted by Maleic Anhydride
Authors:	許曼郁 HSU,MAN-YU
Contributors:	張有義 CHANG, YOU-IM 化學工程與材料工程學系
Keywords:	馬來酸酐;聚乙烯醇 Polyvinyl alcohol;Maleic Anhydride
Date:	2018
Issue Date:	2018-11-07T04:31:47Z (UTC)
Abstract:	本研究主要目的為改善乾式聚乙烯醇縮甲醛泡棉(PVF Foam)的柔軟性質，使用生物可降解性的水溶性高分子聚乙烯醇(PVA)為反應物，藉由聚乙烯醇高分子鏈上的羥基和馬來酸酐上的碳－碳雙鍵易發生自由基反應的特性，利用氧化引發劑過硫酸鉀在溶劑二甲基亞碸中，使馬來酸酐氧化產生自由基開環接枝(grafting)在聚乙烯醇高分子鏈上後，進行交聯改性。本研究所使用之PVA為平均聚合度為500的完全水解型，因此在PVA經過接枝反應之後，微量的馬來酸酐官能基僅取代部分羥基，在整體高分子結構中羥基仍然維持大部分數量，因此後端實驗以選擇水為溶劑，固定小麥澱粉比例為造孔劑，再利用硫酸催化甲醛進行縮醛反應製成聚乙烯醇接枝馬來酸酐縮甲醛泡棉(PVA-MA Foam)。由於微量的馬來酸酐接枝上聚乙烯醇後，高分子支鏈結構中除了含有羥基也含有能結合的酯鍵官能基，這些微量長鏈的會使高分子排列較無序，使得製成PVA-MA Foam之後整體的高分子結構中鏈與鏈的交互作用力較PVF Foam有序排列的短鏈的交互作用力小，使得接枝過後的聚乙烯醇縮甲醛泡棉結晶性較低，而本研究不僅探討PVA與MA的交聯定性分析，也將探討其整體結構與機械性質變化、保水率以及玻璃轉換溫度分析。本研究實驗結果摘要如下：1. 在比對FTIR PVF Foam和PVA-MA Foam的吸收值峰，證實PVA和MA之間確實有酯鍵的產生，使得高分子鏈結構改變。FTIR也證實添加過硫酸鉀的確有提升接枝反應的效果。NMR氫原子吸收電波頻率位移明顯變化，證實其確實受到馬來酸酐官能基的影響。2. PVA經MA接枝後大幅提升柔軟度與伸長量。在SEM分析中證實添加馬來酸酐會影響PVA-MA Foam其表面結構以及孔壁結構，壁上的細孔明顯增加，較空白PVF Foam的壁來得細；但不會影響孔洞大小與數量，對其良好的保水程度也影響不大。3. 藉由玻璃轉換溫度的變化說明添加微量的MA確實影響到其高分子鏈的運動，PVA-MA Foam由於擁有MA官能基接枝在聚乙烯醇分子鏈上，因此在與比較PVF Foam時，其高分子鏈與鏈之間的凡德爾力相互作用力較小，導致結晶性下降，玻璃轉換溫度也隨之降低。 The main purpose of this thesis is to graft Maleic Anhydride (MA) on the chains of Polyvinyl Alcohol (PVA) (which is biodegradable and water soluble as a major reactant in making PVF foams) to improve the soft properties of the corresponded foams in dry condition. In order to let the ring-opened MA molecules graft onto the hydroxyl groups existing on the polyvinyl alcohol polymer chains, since the carbon-carbon double bonds of the maleic anhydride (MA) have the characteristics of being prone to radical reaction by adding peroxides such as potassium persulfate (KPS), so it will be adopted as the initiator of the present experiment of using dimethyl sulfoxide (DMSO) served as the solvent. After grafting and extracting out by acetone, we find that maleic anhydride groups can partially replace the hydroxyl groups of PVA in the present experiment. Those modified PVA-MA molecules are then capable of acetalizing with formaldehyde to produce PVA-MA foam when wheat starches are served as the pore-forming agent. Due to the grafting of maleic anhydride grafted on polyvinyl alcohol based on the formation of ester bonds, which will arise the disordered arrangement happened within the PVF bonds after condensation, and therefore weakening the interactions between the polymer chains. As a result, the crystallinity of the present PVF-MA modified Foam becomes decrease consequently. In the present study, in addition to qualitative analysis of grafting MA on PVA, the changes of the corresponded PVF foam’s mechanical properties, water retention and glass transition temperature will be also inverstigated.This experimental results of this study are summarized as follows: 1. The oxidative grafting of MA onto PVA was verified by FTIR and NMR. In FTIR spectrum, when comparing their absorption peaks of PVA-MA foams, we confirm that the ester bond between PVA and MA do occur. Besides, we also confirm that potassium persulfate (KPS) does improve the grafting reaction. The significant shift in the frequency of the NMR hydrogen-absorbed radio waves also proves the influence of MA grafted on PVA.2. The grafting of MA on PVA significantly increases the softness and elongation. SEM analysis proves that the addition of maleic anhydride does affect the s pore wall structure of PVA-MA Foam. The number of pores existing on the pore walls of PVA-MA foam is significantly increased and pore size is smaller than that of the blank PVF Foam. PVA-MA foam still keep good level of water retention.3. The decrease of the glass transition temperature Tg shows that the grafting of MA on PVA does affect the movement of its polymer chains, which is caused by the lower Van der Waals interaction force interacted between PVF chains, and therefore resulting in a decrease in crystallinity and a decrease in the glass transition temperature of the PVA-MA modified foam.
Appears in Collections:	[化學工程與材料工程學系所] 碩博士論文

Files in This Item:

File	Size	Format
106THU00063004-001.pdf	4851Kb	Adobe PDF	623	View/Open

Loading...