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Effect of ultrasonic irradiation on morphology and polymorphic transformation of glycine
Ultrasonics Sonochemistry ( IF 8.4 ) Pub Date : 2018-04-26
Sevgi Polat, Perviz Sayan

The polymorphic phase transformation of β-glycine to α-glycine was analyzed in the absence and presence of three different intensities of ultrasonic irradiation in a batch system at 25 °C. The experiments were performed to explore the effects of ultrasonic irradiation and its intensity on phase transformation time, morphology, storage stability, and filtration characteristics. The crystals obtained with and without ultrasound were characterized by X-ray diffraction (XRD). The XRD results showed that the ultrasound tended to reduce the transformation time. According to the scanning electron microscopy (SEM) images, the ultrasound had a significant effect on the crystal morphology. The highest ultrasound power applied yielded more rounded crystals compared to the crystals prepared in the absence of ultrasound. In addition to SEM analysis, detailed crystal shape analysis was performed and shape factors, namely the circularity, elongation, and convexity values, were determined quantitatively to get more information about the morphological changes related to the variations in the size and shape of the end products. From the morphological point of view, the circularity values of the crystals obtained under ultrasound were higher but the elongation values were smaller compared to the crystals obtained in the absence of ultrasound. It was also found that higher ultrasound decreased the length and width of the crystals, and the application of ultrasound increased the aspect ratio value from 0.483 to 0.657.



中文翻译:

超声辐射对甘氨酸形态和多态性转化的影响

在25°C的间歇系统中,在不存在和存在三种不同强度的超声辐射的情况下,分析了β-甘氨酸向α-甘氨酸的多晶型相变。进行实验以探索超声辐射及其强度对相变时间,形态,储存稳定性和过滤特性的影响。通过X射线衍射(XRD)表征在有和没有超声的情况下获得的晶体。XRD结果表明,超声倾向于减少转化时间。根据扫描电子显微镜(SEM)图像,超声对晶体形态有重大影响。与没有超声时制备的晶体相比,施加的最高超声功率产生了更多的圆形晶体。除了SEM分析外,进行了详细的晶体形状分析,并定量确定了形状因子,即圆度,伸长率和凸度值,以获取有关与最终产品的尺寸和形状变化有关的形态变化的更多信息。从形态学的观点来看,与没有超声时获得的晶体相比,在超声下获得的晶体的圆度值较高,但伸长率值较小。还发现,较高的超声减小了晶体的长度和宽度,并且超声的应用将长宽比值从0.483增加到0.657。定量确定以获得有关最终产品尺寸和形状变化的形态变化的更多信息。从形态学的观点来看,与没有超声时获得的晶体相比,在超声下获得的晶体的圆度值较高,但伸长率值较小。还发现,较高的超声减小了晶体的长度和宽度,并且超声的应用将长宽比值从0.483增加到0.657。定量确定以获得有关最终产品尺寸和形状变化的形态变化的更多信息。从形态学的观点来看,与没有超声时获得的晶体相比,在超声下获得的晶体的圆度值较高,但伸长率值较小。还发现,较高的超声减小了晶体的长度和宽度,并且超声的应用将长宽比值从0.483增加到0.657。

更新日期:2018-04-26
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