Wang Xinting, Price Erik J, Wnek Gary E, Olah Andrew, Baer Eric
Center for Layered Polymeric Systems (CLiPS), Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.
Polymers (Basel). 2022 Sep 16;14(18):3872. doi: 10.3390/polym14183872.
Continuous tapes of polypropylene (PP) and high-density polyethylene (HDPE) were produced using a novel multiplication co-extrusion process. The structure of the PP/HDPE tapes consists of co-continuous PP and HDPE domains aligned in the extrusion direction, forming a fiber-like composite structure with individual domain thicknesses of 200-500 nm. This unique structure created a significantly large contact interface between the polymer domains. AFM images suggest strong interfacial interactions between incompatible PP and HDPE domains. Orientation at 130 °C was possible due to the enhanced adhesion arising from epitaxial crystallization and the large interfacial area. The modulus, tensile strength, and orientation factor of the oriented composite tapes increased as the draw ratio increased. The existence of two independent shish kabab-like morphologies in the oriented tapes at different draw ratios was indicated by the appearance of two melting peaks for each material. After one-step orientation at 130 °C to a draw ratio of 25, the moduli of the oriented tapes increased to approximately 10 GPa, and the tensile strength increased to approximately 540 MPa. These oriented tapes are stiffer and stronger than commercial tapes and do not fibrillate during the orientation process indicating some interfacial interaction between the domains.
采用一种新型的倍增共挤出工艺制备了聚丙烯（PP）和高密度聚乙烯（HDPE）的连续带材。PP/HDPE带材的结构由沿挤出方向排列的共连续PP和HDPE区域组成，形成了一种纤维状复合结构，单个区域厚度为200 - 500纳米。这种独特的结构在聚合物区域之间形成了显著大的接触界面。原子力显微镜图像表明不相容的PP和HDPE区域之间存在强烈的界面相互作用。由于外延结晶产生的增强粘附力和大的界面面积，在130°C下进行取向是可行的。取向复合带材的模量、拉伸强度和取向因子随着拉伸比的增加而增加。每种材料出现两个熔融峰表明在不同拉伸比的取向带材中存在两种独立的串晶状形态。在130°C下一步取向至拉伸比为25后，取向带材的模量增加到约10 GPa，拉伸强度增加到约540 MPa。这些取向带材比商业带材更硬更强，并且在取向过程中不会原纤化，这表明区域之间存在一些界面相互作用。
