【摘要】：近年來,高分子材料由于其優(yōu)越的綜合性能和相對(duì)較簡(jiǎn)便的加工成型工藝,得到了迅速發(fā)展,而作為五大合成樹脂之一的聚乙烯也存在廣泛的應(yīng)用。但是聚乙烯也存在著耐熱性能差,性脆且耐沖擊性差等缺點(diǎn),通過添加無機(jī)物填充劑對(duì)其進(jìn)行改性是提升性能的一種重要途徑。將磷酸制備過程中得到的α-半水磷石膏晶須填充于聚乙烯中,既可以保留聚乙烯材料的主要特性,又能通過晶須的增強(qiáng)、增韌等優(yōu)勢(shì)改善材料的性能,同時(shí)可以降低材料的成本。本文采用硝酸法酸解磷礦聯(lián)產(chǎn)制備α-半水磷石膏晶須,考察磷酸濃度、硫酸濃度和攪拌速率對(duì)晶須長(zhǎng)徑比的影響;采用五種常規(guī)改性劑對(duì)所得晶須表面進(jìn)行改性處理,研究改性工藝及不同改性劑用量對(duì)晶須改性效果的影響,優(yōu)選出合適的處理工藝和配比;將處理后的α-半水磷石膏晶須填充的聚乙烯材料中半水磷石膏晶須填充的聚乙烯材料中,研究不同填量和不同長(zhǎng)徑比的α-半水磷石膏晶須對(duì)聚乙烯復(fù)合材料性能的影響。結(jié)果如下:(1)當(dāng)磷酸濃度不低于29%時(shí),得到的磷石膏主要成分是α-CaSO_4·0.5H_2O;(2)在90℃溫度下,當(dāng)磷酸濃度為33%,硫酸濃度為39.2%,攪拌速率為400r/min時(shí),得到的α-半水磷石膏晶須長(zhǎng)徑比最大為45;當(dāng)磷酸濃度為37%,硫酸濃度為58.8%,攪拌速率為200r/min時(shí),得到的α-半水磷石膏晶須長(zhǎng)徑比最小為8;(3)在改性溫度為60℃,改性時(shí)間為60min,乙醇用量為α-半水磷石膏晶須的5倍的最佳改性工藝條件下,改性劑為硬脂酸,且用量為5%時(shí),α-半水磷石膏晶須的改性效果最佳;(4)當(dāng)α-半水磷石膏晶須填充量為5份時(shí),聚乙烯復(fù)合材料力學(xué)性能最佳,結(jié)晶度最高,拉伸強(qiáng)度最大為25.0MPa,彎曲強(qiáng)度最大為44.0MPa。原因是此時(shí)晶須均勻分布在基體中,對(duì)聚乙烯材料結(jié)晶有一定誘導(dǎo)作用,結(jié)晶度有所提高;(5)當(dāng)填料含量均為5份,α-半水磷石膏晶須長(zhǎng)徑比為45時(shí)聚乙烯復(fù)合材料的力學(xué)性能比長(zhǎng)徑比為15的要好,且拉伸強(qiáng)度提高4.28%,彎曲強(qiáng)度提高3.41%,沖擊強(qiáng)度提高3.98%。
[Abstract]:In recent years, polymer materials have been developed rapidly because of their superior comprehensive properties and relatively simple processing and molding technology. Polyethylene, one of the five synthetic resins, has also been widely used. However, polyethylene also has some disadvantages, such as poor heat resistance, brittleness and poor impact resistance. It is an important way to improve the properties of polyethylene by adding inorganic filler. The 偽 -hemihydrate gypsum whisker obtained in the preparation of phosphoric acid can not only retain the main properties of polyethylene, but also improve the properties of the material by strengthening and toughening the whisker. At the same time, the cost of materials can be reduced. In this paper, 偽 -hemihydrate phosphogypsum whiskers were prepared by acidolysis of phosphate rock by nitric acid method. The effects of phosphoric acid concentration, sulfuric acid concentration and stirring rate on the aspect ratio of 偽 -hemihydrate gypsum whisker were investigated. The surface of the whisker was modified by five kinds of conventional modifiers. The effects of modification technology and the amount of modifier on the modification effect of whisker were studied. The effect of 偽 -hemihydrate gypsum whisker on the properties of polyethylene composites was studied in the polyethylene materials filled with 偽 -hemihydrate gypsum whiskers with different dosages and different aspect ratios of 偽 -hemihydrate gypsum whiskers. The results are as follows: (1) when phosphoric acid concentration is not less than 29%, the main component of phosphogypsum obtained is 偽-CaSO_4 0.5H _ 2O; (2) at 90 鈩，

本文編號(hào)：2327186