In this study, samples of paraffin-graphite composite were prepared to evaluate the effects of graphite on the impact resistance and neutron attenuation of the composite. This is to address the need for novel-formulated polymers for radiation surveying robots that can withstand radiation effects while having good mechanical properties. The composite samples were made using the melt-mixing method. An Izod impact test based on the ASTM standard was carried out to measure the toughness of the composite. The results suggest that increasing the graphite content from 1 wt% to 5 wt% decreases the composite's impact resistance. 3 mm-thick samples were also examined using neutron radiography at the TRIGA Mk-II research reactor in the Malaysian Nuclear Agency. The grey values in the line profile show an increasing trend with increasing graphite content, indicating decreased thermal neutron absorption/removal. Unseen cracks were also identified in the neutron image. The shielding performance was evaluated using attenuation experiments at two different thicknesses. The results reveal that adding graphite to paraffin can improve its neutron shielding capability up to certain weight percentages. Increasing the graphite content further than 3 wt% caused an increase in neutron transmission, likely due to the buildup effect. The impact resistance of the composite is higher than that of pure paraffin. However, the resistance decreases with graphite content. Overall, the most optimal formulation in the context of this study in terms of impact resistance and neutron shielding performance was paraffin+2 wt% graphite.

中文翻译：

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石墨-石蜡复合材料的中子射线照相、抗冲击性和热中子衰减分析

在本研究中，制备了石蜡-石墨复合材料样品，以评估石墨对复合材料抗冲击性和中子衰减的影响。这是为了满足辐射测量机器人对新型聚合物的需求，这些聚合物可以承受辐射效应，同时具有良好的机械性能。复合材料样品是采用熔融混合方法制备的。进行基于 ASTM 标准的悬臂梁冲击试验来测量复合材料的韧性。结果表明，将石墨含量从 1 wt% 增加到 5 wt% 会降低复合材料的抗冲击性。还在马来西亚核机构的 TRIGA Mk-II 研究反应堆中使用中子射线照相术检查了 3 毫米厚的样品。线轮廓中的灰度值随着石墨含量的增加而呈现增加的趋势，表明热中子吸收/去除减少。中子图像中还发现了看不见的裂纹。使用两种不同厚度的衰减实验来评估屏蔽性能。结果表明，在石蜡中添加石墨达到一定重量百分比可以提高石蜡的中子屏蔽能力。将石墨含量增加超过 3 wt% 会导致中子传输增加，这可能是由于堆积效应所致。复合材料的抗冲击性能比纯石蜡高。然而，电阻随着石墨含量的增加而降低。总体而言，在本研究中，就抗冲击性和中子屏蔽性能而言，最佳配方是石蜡+2 wt%石墨。