本文選題：環(huán)氧樹脂　切入點：2-丙烯酰胺基-2-甲基丙磺酸　出處：《中南大學(xué)》2005年碩士論文

【摘要】：化學(xué)改性法制得的環(huán)氧樹脂乳液不含小分子表面活性劑,具備自乳化結(jié)構(gòu),且分散相粒子的尺寸很小,可以達(dá)到納米級,因此備受關(guān)注。文獻(xiàn)報導(dǎo)的制備陰離子水性環(huán)氧樹脂的改性劑主要是丙烯酸類單體。羧基被引入到環(huán)氧樹脂分子鏈中,再中和成鹽使樹脂獲得水分散性。這種途徑得到的環(huán)氧樹脂乳液在弱堿性條件才能穩(wěn)定,當(dāng)pH值改變時乳液體系容易結(jié)塊與凝膠,不利于儲存與使用。 本研究以丙烯酰胺基-2-甲基丙磺酸(AMPS)為水性單體,對環(huán)氧樹脂進(jìn)行改性。此共聚物不需中和,就能獲得良好的水分散性。設(shè)計出了AMPS改性環(huán)氧樹脂的反應(yīng)路線,通過正交實驗和對比實驗,對反應(yīng)物配比、聚合溫度和引發(fā)劑用量等反應(yīng)條件進(jìn)行了優(yōu)化,并探討了影響反應(yīng)穩(wěn)定性的因素。由于AMPS的高聚合活性,須采用一些較為特殊的單體滴加方法,以保證共聚反應(yīng)的穩(wěn)定進(jìn)行。結(jié)果發(fā)現(xiàn),原料配比環(huán)氧樹脂:AMPS(摩爾比)為1:2,反應(yīng)溫度為110℃,引發(fā)劑用量為1.5%時得到的高聚物收率可達(dá)69.1%。測試了反應(yīng)過程中特性粘數(shù)[η]、體系酸值及高聚物的收率隨反應(yīng)時間的變化規(guī)律。利用紅外光譜表征了共聚物的結(jié)構(gòu),并對所得乳液的各項穩(wěn)定性進(jìn)行了測試,對聚合反應(yīng)的表觀性質(zhì)進(jìn)行了描述。 從反應(yīng)體系的酸值隨反應(yīng)時間下降推測,除了在BPO引發(fā)劑作用下AMPS與環(huán)氧樹脂主鏈上的接枝反應(yīng)之外,還有AMPS的磺酸基團(tuán)與環(huán)氧樹脂的環(huán)氧基的擴(kuò)鏈反應(yīng)發(fā)生。于是本論文中進(jìn)行了三個平行實驗,探討反應(yīng)的機(jī)理。結(jié)果發(fā)現(xiàn),整個實驗中接枝反應(yīng)和環(huán)氧基的開環(huán)反應(yīng)同時進(jìn)行,二者在反應(yīng)的前期和后期分別居于主導(dǎo)地位。從測定高聚物的DSC和TG曲線,有兩個玻璃化溫度,證實了對反應(yīng)機(jī)理的推斷。以反應(yīng)體系中環(huán)氧樹脂的濃度變化為對象,用微商法求出了AMPS與環(huán)氧樹脂反應(yīng)的總反應(yīng)和接枝反應(yīng)的活化能和速率常數(shù),發(fā)現(xiàn)環(huán)氧樹脂分子鏈上的鏈自由基產(chǎn)生速率是控制接枝與擴(kuò)鏈反應(yīng)進(jìn)行的關(guān)鍵。 聚合物乳液的粒徑分布和聚合時間有關(guān)。隨著時間的延長,聚合物乳液的粒徑先減小后增大,且分布變寬,原因是反應(yīng)后期主要發(fā)生的是開環(huán)反應(yīng),消耗了體系中磺酸基,生成了疏水性的磺酸酯基,使AMPS改性環(huán)氧樹脂的水分散性下降。研究中還發(fā)現(xiàn)乳液的粒徑與AMPS的用量有密切關(guān)系,隨著AMPS量的增加,產(chǎn)物水分散體的
[Abstract]:The epoxy emulsion prepared by chemical modification does not contain small molecular surfactants and has self-emulsifying structure, and the size of dispersed particles is very small, which can reach nanometer level. The main modifier for the preparation of anionic waterborne epoxy resin is acrylic monomers. The carboxyl group is introduced into the molecular chain of epoxy resin. The epoxy resin emulsion obtained by neutralization and salt formation can only be stabilized under weak alkaline conditions. When pH value is changed, the emulsion system is easy to agglomerate and gel, which is not conducive to storage and use. In this study, epoxy resin was modified with acrylamide (2-methylpropanesulfonic acid) as waterborne monomer. The copolymers could obtain good water dispersion without neutralization. The reaction route of AMPS modified epoxy resin was designed. By orthogonal and comparative experiments, the reaction conditions such as the ratio of reactants, polymerization temperature and initiator dosage were optimized, and the factors affecting the stability of the reaction were discussed. Some special monomer dropping methods were used to ensure the stability of the copolymerization. It was found that the molar ratio of epoxy resin to epoxy resin was 1: 2 and the reaction temperature was 110 鈩，

本文編號：1668129