Mechanism of Low‐Temperature Brittle–Ductile Transition of Polypropylene/Low‐Density Polyethylene Blend Foam under Compressive Stress Caused by Cell Stretching

Abstract

To enhance the low‐temperature toughness of polypropylene/low density polyethylene (PP/LDPE) blend, which is a crucial blend for polyolefin material with wide applications in frigid regions, the PP/LDPE blend foam with stretched cells is fabricated via a facile injection foaming together with open‐mold stretching process. During the open‐mold stretching, the relatively miscible PP and LDPE chains are debonded, and then the stretched and oriented cells structure with lots of tiny interphase cavities between the PP and LDPE phases and the fine lamellae are formed in the foam system. Such interphase cavities provide an adequate movement space for the frozen PP and LDPE chains and lamellae, and effectively relaxed and transferred stress, which greatly promote the uniform compressive behavior accompanied by the completely compacted cells at −25 °C. Moreover, the compressive fracture surface changes from relatively flat and smooth for the stretched PP foam to obvious yield folds and deformation for the stretched blend foam, and the compressive strain of stretched PP/LDPE blend foam is highly enhanced by a roughly 31%, 53%, and 44% increase than that of PP, PP/LDPE, and stretched PP foam samples, respectively, achieving the low‐temperature brittle–ductile transition for PP.

Trial Manufacture and Performance Research of Hydraulic Oil Tank for Three Kinds of Non-Metallic Materials

“…After the test, the HOT of the XLPE and PA materials did not show any obvious damage, while the PP HOT was smashed, as depicted in Figure 13. This is due to the relatively poor flexibility of the molecular chains of the PP material, which exhibits inferior low-temperature toughness compared to XLPE and PA materials, making the PP material-based HOT less resistant to low temperatures and unsuitable for use under such conditions [23].…”

Effects of Friction Stir Welding on the Mechanical Behaviors of Extrusion-Based Additive Manufactured Polymer Parts

“…Furthermore, the tensile fractured surfaces of the welding workpieces were also observed after gold was sprayed directly. For the sample preparation method, one can refer to our previous research on injection molding samples [ 37 , 38 , 39 , 40 , 41 , 42 ].…”

Hybrid reinforced effect of long carbon fiber and short glass fiber on polycarbonate foams

“…For example, by creating a microporous structure during the processing operations, PC foams can be advantageous for many structuralize and/or functionalize applications such as thermal insulation, sound absorption, separation media, and so forth. However, the cellular structure was inevitably influenced and even decided by the foaming processing, resulting in different properties of the foamed part 18–21 . Similar to other polymers, PC foams can generally be fabricated via the three most popular foaming operations, that is, batch, extrusion, and injection molding foaming operations, and meanwhile, a blowing agent, which possibly involves physical blowing agents (supercritical CO 2 , nitrogen, and water) and chemical blowing agents, is used for releasing gas and generating the porous structure.…”