Aniśko Joanna, Barczewski Mateusz, Piasecki Adam, Skórczewska Katarzyna, Szulc Joanna, Szostak Marek
Institute of Materials Technology, Faculty of Mechanical Engineering, Poznan University of Technology, Piotrowo 3, 61-139 Poznan, Poland.
Institute of Materials Engineering, Faculty of Materials Engineering and Technical Physics, Poznan University of Technology, Piotrowo 3, 61-138 Poznan, Poland.
Materials (Basel). 2022 Aug 26;15(17):5903. doi: 10.3390/ma15175903.
Rotational molding is a technology in which polymeric thin-walled products can be made. The newest descriptions of this technology concern the possibility of obtaining polymer composite materials. There are two main methods of incorporating fillers into a polymer matrix. Dry blending is based on mixing fillers with polymer powders before rotational molding by hand or using automatic mixers. In the melt compounding method, fillers are mixed with the polymer in the preliminary step by melt processing and then grinding or pulverization to obtain polymer powders for rotational molding. This work aimed to investigate the impact of the processing procedure on the structure and properties of biobased composites with expanded vermiculite. Produced rotomolded parts were examined using mechanical tests to assess changes in tensile, flexural, and impact properties. The most significant difference in mechanical properties was noted for samples with 10 wt% expanded vermiculite (EV). The elasticity modulus increases by almost 2 fold when the sample is prepared in a two-step process, the tensile strength is 4-fold higher, the flexural modulus is 3-fold higher, and the flexural strength is 5-fold higher. We also investigated thermomechanical properties in DMA measurement. The void volume content was also measured to control the quality of obtained parts. The porosity of dry blended samples containing more than 2 wt% EV is almost 2-fold higher. Other methods to control quality and structure were optical and scanning electron microscopy used for rotomolded parts and polymer powders. The investigations of rotomolded parts were supplemented with a complete description of used materials, including the particle size distributions of polymer powders and filler. Analysis of the thermal properties and chemical structure was also performed despite all the mechanical tests. The emerging conclusions from the research clearly show that the two-step process allows for achieving a more beneficial mechanical performance of the composites made of the biobased polymer in rotational molding technology.
滚塑成型是一种可制造聚合物薄壁产品的技术。关于这项技术的最新描述涉及获得聚合物复合材料的可能性。将填料加入聚合物基体有两种主要方法。干混法是在滚塑成型前通过手工或使用自动混合器将填料与聚合物粉末混合。在熔融共混法中，填料在初步步骤中通过熔融加工与聚合物混合，然后进行研磨或粉碎以获得用于滚塑成型的聚合物粉末。这项工作旨在研究加工工艺对含膨胀蛭石的生物基复合材料的结构和性能的影响。使用机械测试对生产的滚塑部件进行检查，以评估拉伸、弯曲和冲击性能的变化。对于含有10 wt%膨胀蛭石（EV）的样品，机械性能的差异最为显著。当样品采用两步法制备时，弹性模量几乎增加了2倍，拉伸强度提高了4倍，弯曲模量提高了3倍，弯曲强度提高了5倍。我们还在动态热机械分析（DMA）测量中研究了热机械性能。还测量了空隙体积含量以控制所得部件的质量。含有超过2 wt% EV的干混样品的孔隙率几乎高出2倍。控制质量和结构的其他方法是对滚塑部件和聚合物粉末使用光学显微镜和扫描电子显微镜。对滚塑部件的研究还补充了所用材料的完整描述，包括聚合物粉末和填料的粒度分布。尽管进行了所有机械测试，但也对热性能和化学结构进行了分析。该研究得出的新结论清楚地表明，两步法能够在滚塑成型技术中使由生物基聚合物制成的复合材料获得更有利的机械性能。
