本文關(guān)鍵詞： 氯氧鎂水泥 磷酸 聚合物 耐水性 復(fù)合改性　出處：《江蘇大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：氯氧鎂水泥(MOC)屬于氣硬性膠凝材料,具有早強(qiáng)、高強(qiáng)、快凝、耐磨、耐腐蝕、防火抗凍、粘結(jié)力強(qiáng)、低堿、加工性能好等一系列優(yōu)點(diǎn),但同時(shí)也存在不耐水、易吸潮返鹵、變形、吸水后強(qiáng)度嚴(yán)重下降等許多缺陷。所以氯氧鎂水泥在工程應(yīng)用方面具有很大的局限性,目前主要用于制備地板材料、包裝材料、裝飾材料等非承重材料,以及耐火制品、磨具磨料、代木制品等。為解決氯氧鎂水泥耐水性差的問題,本論文提出利用磷酸與高分子聚合物復(fù)合改善氯氧鎂水泥耐水性的方法,以水化產(chǎn)物表面形成的磷酸鎂和耐水聚合物膜層的結(jié)構(gòu)與形成機(jī)理為研究對(duì)象,結(jié)合XRD、SEM和FTIR等微觀測(cè)試方法,研究磷酸-MOC、聚合物-MOC和磷酸-聚合物-MOC體系的耐水機(jī)制,初步探討磷酸、聚合物復(fù)合改性的改性機(jī)理,為氯氧鎂水泥耐水性的有效改善和廣泛應(yīng)用提供理論依據(jù)和技術(shù)支撐。本論文主要得出以下研究結(jié)論:(1)磷酸可顯著提高氯氧鎂水泥的耐水性,但存在緩凝作用,磷酸摻量一般選擇為1%。通過磷酸溶液處理空白試樣表面的方法,發(fā)現(xiàn)表面生成的MgHPO_4·3H_2O可促進(jìn)試樣耐水性的提高,這是由于[PO_4]~(3-)與Mg~(2+)生成的難溶性磷酸鹽附著在晶相表面,阻止或抑制水化產(chǎn)物的水解,從而提高耐水性。(2)單摻苯丙乳液不能改善氯氧鎂水泥的耐水性,甚至使耐水性變差,這是由于苯丙乳液中的低聚物不能自發(fā)吸附在水化產(chǎn)物晶相表面,無法形成有效的耐水保護(hù)膜。但是復(fù)摻磷酸鈉與苯丙乳液可有效提高氯氧鎂水泥的耐水性,當(dāng)復(fù)摻1%磷酸鈉與8%苯丙乳液時(shí)軟化系數(shù)可達(dá)到0.93。在磷酸根離子([PO_4]~(3-))存在的條件下,[PO_4]~(3-)與Mg~(2+)相結(jié)合吸附在水化產(chǎn)物表面,使表面呈現(xiàn)出極強(qiáng)的負(fù)電性,誘導(dǎo)體系中的膠體顆粒遷移并吸附到水化產(chǎn)物表面上,形成均勻穩(wěn)定的耐水薄膜,從而提高氯氧鎂水泥的耐水性能。(3)常溫固化的熱固性樹脂可在一定程度上提高水泥的耐水性,且復(fù)摻磷酸與樹脂效果更佳。本實(shí)驗(yàn)研究了不飽和聚酯樹脂、乙烯基樹脂、氨基樹脂,發(fā)現(xiàn)氨基樹脂的改性效果最佳,且液態(tài)氨基樹脂的改性效果要優(yōu)于粉狀氨基樹脂,當(dāng)復(fù)摻1%磷酸與10%氨基樹脂時(shí),水泥的7d軟化系數(shù)能達(dá)到1左右。當(dāng)磷酸存在時(shí),氨基樹脂易在水化產(chǎn)物表面形成防水膜層,對(duì)5相晶體的保護(hù)效果較好。
[Abstract]:Magnesium oxychloride cement (MOC) is a kind of gas-hard cementing material. It has a series of advantages, such as early strength, high strength, quick solidification, wear resistance, corrosion resistance, fire resistance, strong adhesion, low alkali, good processability, etc. So magnesium oxychloride cement has great limitations in engineering application. At present, it is mainly used in the preparation of floor materials, packaging materials, decorative materials and other non-load-bearing materials, as well as refractory products. In order to solve the problem of poor water resistance of magnesium oxychloride cement, a method of improving water resistance of magnesium oxychloride cement with phosphoric acid and polymer was put forward. The structure and formation mechanism of magnesium phosphate and water-resistant polymer coatings formed on the surface of hydrated products were studied. The mechanism of water resistance of phosphoric acid (Phosphoric acid), polymer (MOC) and phosphoric acid-polymer-MOC (PPO-MOC) systems was studied by means of XRD-SEM and FTIR. The modification mechanism of phosphoric acid and polymer composite modification was discussed. The main conclusions of this paper are as follows: 1) Phosphoric acid can significantly improve the water resistance of magnesium oxychloride cement, but it has retarding effect. The content of phosphoric acid is generally chosen as 1. By treating the surface of blank sample with phosphoric acid solution, it is found that MgHPO_4 路3H _ 2O generated on the surface can improve the water resistance of the sample, which is due to the adhesion of insoluble phosphate formed by [PO_4] / Mg~(2) to the surface of crystalline phase. The water resistance of magnesium oxychloride cement can not be improved by preventing or inhibiting the hydrolysis of hydration products, thereby improving the water resistance of magnesium oxychloride cement. This is because the oligomer in the styrene-acrylic emulsion can not be spontaneously adsorbed on the crystalline surface of the hydration product and can not form an effective water-resistant protective film, but the co-doped sodium phosphate and styrene-acrylic emulsion can effectively improve the water resistance of magnesium oxychloride cement. When mixed with 1% sodium phosphate and 8% styrene-acrylic emulsion, the softening coefficient can reach 0.93. Under the condition of the presence of [PO_4] ([PO_4] ~ (3-O)), [PO_4] ~ (3) and Mg~(2) are adsorbed on the surface of the hydration product, which makes the surface of the hydrated product exhibit very strong negative electric properties. The colloidal particles in the system were induced to migrate and adsorbed onto the surface of the hydration products to form a uniform and stable water resistant film, thus improving the water resistance of magnesium oxychloride cement. 3) the thermosetting resin cured at room temperature could improve the water resistance of the cement to a certain extent. In this experiment, unsaturated polyester resin, vinyl resin and amino resin were studied. It was found that the modification effect of amino resin was the best, and the modification effect of liquid amino resin was better than that of powder amino resin. When mixed with 1% phosphoric acid and 10% amino resin, the softening coefficient of cement can reach about 1 in 7 days. In the presence of phosphoric acid, the amino resin can easily form a waterproof film on the surface of the hydrated product, and the protective effect of the 5-phase crystal is better.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ172.1

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