Laboratory of Polymeric and Composite Materials, Materia Nova Materials R&D Center & UMONS Innovation Center, 3 Avenue Copernic, 7000 Mons, Belgium.
Laboratory of Polymeric and Composite Materials, Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons (UMONS), Place du Parc 20, 7000 Mons, Belgium.
Int J Mol Sci. 2023 Aug 10;24(16):12659. doi: 10.3390/ijms241612659.
To develop novel mineral-filled composites and assess their enhanced properties (stiffness, a good balance between mechanical strength and impact resistance, greater temperature stability), a high-impact polypropylene copolymer (PPc) matrix containing an elastomeric discrete phase was melt mixed with natural CaSO β-anhydrite II (AII) produced from gypsum rocks. First, in a prior investigation, the PPc composites filled with AII (without any modification) displayed enhanced stiffness, which is correlated with the relative content of the filler. The tensile and impact strengths dramatically decreased, especially at high filling (40 wt.%). Therefore, two key methods were considered to tune up their properties: (a) the ionomeric modification of PPc composites by reactive extrusion (REx) with zinc diacrylate (ZA), and (b) the melt mixing of PPc with AII surface modified with ethylenebis(stearamide) (EBS), which is a multifunctional processing/dispersant additive. The properties of composites produced with twin-screw extruders (TSEs) were deeply assessed in terms of morphology, mechanical, and thermal performance, including characterizations under dynamic mechanical solicitations at low and high temperatures. Two categories of products with distinct properties are obtained. The ionomeric modification by Rex (evaluated by FTIR) led to composites characterized by remarkable thermal stability, a higher temperature of crystallization, stronger interfacial interactions, and therefore noticeable mechanical properties (high tensile strength (i.e., 28 MPa), increased stiffness, moderate (3.3 kJ/m) to good (5.0 kJ/m) impact resistance) as well as advanced heat deflection temperature (HDT). On the other hand, the surface modification of AII with EBS facilitated the dispersion and debonding of microparticles, leading to composites revealing improved ductility (strain at break from 50% to 260%) and enhanced impact properties (4.3-5.3 kJ/m), even at high filling. Characterized by notable mechanical and thermal performances, high whiteness, and a good processing ability, these new PPc-AII composites may be tailored to meet the requirements of end-use applications, ranging from packaging to automotive components.
为了开发新型填充矿物复合材料并评估其增强性能（刚性、机械强度与抗冲击性之间的良好平衡、更高的温度稳定性），采用高抗冲共聚聚丙烯（PPc）基体与天然无水石膏 II（AII）（由石膏岩生产）进行熔融共混，其中基体含有弹性离散相。首先，在先前的研究中，填充 AII 的 PPc 复合材料（未经任何改性）显示出增强的刚性，这与填料的相对含量有关。拉伸强度和冲击强度显著降低，特别是在高填充量（40wt.%）时。因此，考虑了两种关键方法来调整它们的性能：（a）通过用锌二丙烯酸酯（ZA）进行反应挤出（REx）对 PPc 复合材料进行离聚物改性，和（b）通过熔融共混将 PPc 与经乙撑双硬脂酰胺（EBS）表面改性的 AII 混合，EBS 是一种多功能加工/分散添加剂。使用双螺杆挤出机（TSE）对复合材料的性能进行了深入评估，包括形态、机械和热性能，包括在低温和高温下进行动态力学刺激下的特性。获得了两类具有不同性能的产品。Rex 的离聚物改性（通过 FTIR 评估）导致复合材料具有显著的热稳定性、更高的结晶温度、更强的界面相互作用，因此具有显著的机械性能（高拉伸强度（即 28MPa）、增加的刚性、中等（3.3kJ/m）到良好（5.0kJ/m）的抗冲击性）以及先进的热变形温度（HDT）。另一方面，AII 用 EBS 进行表面改性促进了微粒子的分散和脱粘，导致复合材料显示出改善的延展性（断裂伸长率从 50%提高到 260%）和增强的冲击性能（4.3-5.3kJ/m），即使在高填充量下也是如此。这些新型 PPc-AII 复合材料具有显著的机械和热性能、高白度和良好的加工能力，可根据包装到汽车零部件等最终用途应用的要求进行定制。
