In the present work, a proposal for the recycling of ethylene vinyl acetate (EVA) foam waste from the footwear industry using twin-screw extruder was evaluated. Parameters such as antioxidant addition, number of reprocessing, temperature, rotation speed were evaluated. The recycled material was evaluated by means of gel content, scanning electron microscopy (SEM), thermogravimetry (TG) and parallel plate rheometry. From this, the 4 samples were chosen, from the 16 extruded, with a higher probability of forming homogeneous foams to be used in the manufacture of new EVA foams. The foams were evaluated using scanning electron microscopy (SEM), dynamic mechanical analysis (DMA) and physical tests of density, abrasion and permanent compression deformation (PCD). The results showed a decrease in the content of crosslinked gel by up to 13 percentage points for the recycled material with antioxidant. However, there was a possible residual crosslinking, as the crosslinking of all recycled foams was greater than reference (foam). The greatest recycled material homogeneity, observed in the SEM, occurred in the samples processed for five repetitions without antioxidant. Some foams manufactured with recycled waste presented very similar morphological aspects to the reference foam. Foam manufactures with G1 recycled waste (extruded once, at 180°C, 450 rpm, without antioxidant), presented the most uniform and spherical cells. This foam also presented the best responses for the physical tests of PCD and abrasion, even compared to foam without recycle. As well as the lower viscosities for these same samples compared to the previous processing. It was understood that the viscosity of the recycled waste directly interferes with the formation of new EVA foam. Rheometry made it possible to identify the recycling process that resulted in an ideal viscosity material for incorporation in the manufacture of new EVA foams.

在目前的工作中，评估了使用双螺杆挤出机回收制鞋业的乙烯乙酸乙烯酯（EVA）泡沫废料的建议。评价了抗氧化剂的添加，再加工次数，温度，转速等参数。通过凝胶含量，扫描电子显微镜（SEM），热重法（TG）和平行板流变法评估回收的材料。从中，从16个挤出物中选择了4个样品，形成高均质泡沫的可能性更高，可用于制造新的EVA泡沫。使用扫描电子显微镜（SEM），动态力学分析（DMA）以及密度，磨耗和永久压缩变形（PCD）的物理测试对泡沫进行评估。结果表明，含抗氧化剂的再生材料的交联凝胶含量降低了13个百分点。但是，可能存在残留的交联，因为所有回收泡沫的交联都大于参考（泡沫）。在SEM中观察到的最大回收材料均质性发生在经过五次重复处理且无抗氧化剂的样品中。用再生废料制造的某些泡沫在形态方面与参考泡沫非常相似。含有G1再生废料（在180°C，450 rpm下挤出一次，不含抗氧化剂）的泡沫制品呈现出最均匀的球形泡孔。即使与没有回收的泡沫相比，这种泡沫也对PCD和磨损的物理测试表现出最佳响应。与之前处理相比，这些相同样品的粘度更低。可以理解，回收废物的粘度直接干扰了新的EVA泡沫的形成。流变仪使人们有可能识别出回收过程，从而找到了一种理想的粘性材料，可用于制造新的EVA泡沫。