天然石膏改性及填充树脂的实验研究

发布时间：2018-02-25 18:11

本文关键词： 天然二水石膏硬脂酸表面改性聚苯乙烯(PS) 聚甲基丙烯酸甲酯(PMMA)　出处：《武汉工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：天然石膏是我国储量大且分布广泛的优势非金属矿产之一,广泛应用于塑料、橡胶、涂料和纸张等行业,但天然石膏作为填料使用时,存在与高分子相容性不足的缺点,需要通过表面改性改善天然石膏在有机高分子基材的分散性。本课题针对硬脂酸表面改性天然二水石膏(GY)及改性天然二水石膏(MGY)的应用展开了相关的实验研究。采用活化指数确定硬脂酸改性GY的最佳体系,应用傅立叶红外光谱(FT-IR)、扫描电镜(SEM)、X射线衍射(XRD)、接触角、相容性分析等多种手段对MGY进行表征。并通过溶液共混法,以MGY为填料,聚苯乙烯(PS)、聚甲基丙烯酸甲酯(PMMA)为基质,制备MGY-PS、MGY-PMMA复合材料。针对MGY-PS复合材料,利用SEM考察了MGY在PS中的分散性及其对PS基材的影响,并通过机械性能、热稳定性的测量综合评价其物理性能。而对于MGY-PMMA复合材料主要进行力学性能、热稳定性能及透光率的测定。得到的主要结论如下:1.使用硬脂酸改性GY时,最佳的改性体系为改性剂用量6%,改性温度60 oC,改性时间40 min,改性pH 7。该情况下得到的MGY,活化指数达到100%,为最佳。2.硬脂酸改性GY粉体时,硬脂酸根通过取代GY颗粒表面羟基,破坏GY颗粒团聚体的表面层稳定性,从而达到改性的效果。而经过改性后得到的MGY,其热稳定性提高,表面接触角由35.64°增加到87.47°,与液体石蜡有较好的相容性。3.在PS高分子体系中,复合材料的阻燃性能会因MGY粉体的添加而得到较大程度的提高,在MGY的填充量为20%时,能将易燃的PS高分子材料转变为可燃材料,在MGY的填充量为50%时,会得到难燃的MGY-PS复合材料;在PS高分子体系中,填料的添加,使得复合材料的机械性较纯PS有较大程度的提高。当填料与树脂的质量比为1:5时,GY-PS复合材料的拉伸强度较纯PS体系得到4%的增加量,而断裂伸长率得到8%的增加;而同等填充率的情况下,MGY对复合材料机械性能的促进作用更为明显,MGY-PS复合体系的拉伸强度较纯PS体系增加6%,断裂伸长率为纯PS体系的110%。4.在PMMA高分子体系中,添加MGY粉体能在一定程度上提高PMMA材料的热稳定性,但MGY的添加量会严重影响复合材料的透光率,在填充量在1%下时,复合材料的透光率能保持在80%以上;在PMMA高分子体系中,MGY对PMMA机械强度的促进作用较为明显。当MGY的填充量为2%时,MGY-PMMA复合体系的拉伸强度较纯PMMA体系增加28%,断裂伸长率增大至纯PMMA体系的118%。
[Abstract]:Natural gypsum is one of the most abundant and widely distributed non-metallic minerals in China. It is widely used in plastics, rubber, coatings and paper industries. However, when used as filler, natural gypsum has the disadvantage of insufficient compatibility with polymer. It is necessary to improve the dispersion of natural gypsum in organic polymer substrate by surface modification. In this paper, the application of stearic acid surface modified natural gypsum (GY) and modified natural gypsum dihydrate (MGY) were studied. The optimum system of stearic acid modified GY was determined by activation index. The MGY was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), contact angle, compatibility analysis and so on. The MGY was characterized by solution blending, using MGY as the filler, polystyrene (PS) and poly (methyl methacrylate) (PMMA) as the matrix. MGY-PSN MGY-PMMA composites were prepared. For MGY-PS composites, the dispersion of MGY in PS and its influence on PS substrate were investigated by SEM. The mechanical properties, thermal stability and transmittance of MGY-PMMA composites were measured. The main conclusions are as follows: 1.When stearic acid was used to modify GY, The optimum modification system is the dosage of modifier 6, modification temperature 60 OC, modification time 40 min, modification pH 7. The activation index of MGY obtained under this condition is 100. 2. When stearic acid modifies GY powder, stearic acid radical replaces the surface hydroxyl of GY particles. The stability of the surface layer of the agglomerates of GY particles was destroyed and the effect of modification was achieved. However, the thermal stability of the modified MGY was improved, the contact angle of the surface was increased from 35.64 掳to 87.47 掳, and the surface contact angle was increased from 35.64 掳to 87.47 掳, which had good compatibility with liquid paraffin. The flame retardancy of the composites can be greatly improved by the addition of MGY powder. When the content of MGY is 20, the flammable PS polymer can be changed into combustible material, and when the content of MGY is 50, In PS polymer system, the addition of filler, When the mass ratio of filler to resin is 1: 5, the tensile strength of GY-PS composite is 4% higher than that of pure PS system, and the elongation at break is 8%. The tensile strength of MGY-PS composite system is 6% higher than that of pure PS system, and the elongation at break is 110. 4% of pure PS system. In PMMA polymer system, the tensile strength of MGY-PS composite system is more obvious than that of pure PS system, and the tensile strength of MGY-PS composite system is more obvious than that of pure PS system, and the elongation at break is 110. 4% of pure PS system. The addition of MGY powder can improve the thermal stability of PMMA material to some extent, but the content of MGY will seriously affect the transmittance of the composite. When the content of MGY is 1%, the transmittance of the composite can be kept above 80%. The effect of MGY on the mechanical strength of PMMA is obvious in PMMA polymer system. When the filling amount of MGY is 2, the tensile strength of MGY-PMMA composite system increases by 28% and the elongation at break increases to 118% of pure PMMA system.
【学位授予单位】：武汉工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ177.37

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