开放醇水体系制备磷石膏基无水石膏晶须及在丁腈橡胶中的应用探索

以磷石膏(PG)为原料,通过开放体系醇水热法制备半水硫酸钙(HH)晶须,研究了晶形控制剂十六烷基三甲基溴化铵(CTAB)对晶须形貌和物相的影响。结果表明,加入0.05 wt%CTAB时,得到的HH晶须呈纤维状,表面光滑,长径比高达43。将HH进行通过煅烧制备无水硫酸钙(AH)晶须,研究了煅烧温度对晶须物相和形貌的影响。研究发现HH晶须在600℃下煅烧2 h后,晶须由HH完全转化为AH,且晶须形貌未发生改变。研究了不同表面改性剂对晶须表面疏水性能的影响,研究发现用硅酸钠-硬脂酸(无机-有机)双重改性AH晶须,晶须表面由亲水性转变为疏水性。研究了改性后的AH晶须对丁腈橡胶密封衬垫性能的影响,研究发现密封衬垫横向拉伸强度略低于标准值,AH晶须不能替代RS4021矿物纤维。

Preparation of Phosphogypsum-Based Anhydrite Whiskers by Open Alcoholic Water System and its Application in Nitrile Rubber

In this paper,phosphogypsum(PG)is used as raw material to prepare calcium sulfate hemihydrate(HH)whiskers by open system alcohol hydrothermal method.The effect of crystal form control agent cetyltrimethylammonium bromide(CTAB)on whisker morphology and phase was studied.The results show that when 0.05 wt%CTAB is added,the obtained HH whiskers are fibrous,the surface is smooth,and the aspect ratio is as high as 43.HH was prepared by calcination to prepare anhydrous calcium sulfate(AH)whiskers,and the effects of calcination temperature on whisker phase and morphology were studied.It was found that after the HH whisker was calcined at 600℃for 2 h,the whiskers were completely converted from HH to AH,and the whisker morphology did not change.The effects of different surface modifiers on the hydrophobic properties of whisker surface were studied.It was found that AH whiskers were doublemodified with sodium silicate-stearic acid(inorganic-organic),and the whisker surface changed from hydrophilic to hydrophobic.The effect of modified AH whiskers on the properties of nitrile rubber gaskets was studied.It was found that the transverse tensile strength of the gaskets was slightly lower than the standard value,and AH whiskers could not replace RS4021 mineral fibers.