Exploring the Effects of MXene on Nonisothermal Crystallization and Melting Behavior of β-Nucleated Isotactic Polypropylene

Abstract

In this study, one of the commonly used MXene (Ti3C2Tx) and β nucleated isotactic polypropylene (β-iPP)/MXene composites of different compositions were fabricated. The effects of MXene on non-isothermal crystallization and polymorphic behavior of β-iPP/MXene composites were comparatively studied. The non-isothermal crystallization kinetics indicates that for all samples, the lower cooling rates promote composites to crystallize at higher temperatures. When MXene and β-Nucleating agent (β-NA) are added separately, the crystallization temperature of composites shifts towards higher temperatures at all cooling rates. When MXene and β-NA are added simultaneously, the composite shows different cooling rate dependence, and the effects of improving crystallization temperatures is more obvious under rapid cooling. The activation energy of four samples iPP, iPP/MXene, iPP/β-NA, and iPP/MXene/β-NA were −167.5, −185.5, −233.8, and −218.1 kJ/mol respectively, which agree with the variation tendency of crystallization temperatures. The polymorphic behavior analysis obtained from Differential Scanning calorimetry (DSC) is affected by two factors: the ability to form β-crystals and the thermal stability of β-crystals. Because β-crystals tend to recrystallize to α-crystals below a critical temperature, to eliminate the effect of β-α recrystallization, the melting curves at end temperatures Tend = 50 °C and Tend = 100 °C are comparatively studied. The results show that more thermally unstable β-crystals would participate in β-α recrystallization with higher cooling rates. Moreover, thermal stability of β-crystals is improved by adding MXene. To further verify these findings, samples of three different thermal conditions were synthesized and analyzed by DSC, X-Ray Diffraction (XRD), and Polarized Light Optical Microscopy (PLOM), and the results were consistent with the above findings. New understandings of synthesizing β-iPP/MXene composites with adjustable morphologies and polymorphic behavior were proposed.

Aromatic Amide-Based Hindered Amine Derivative as an Efficient Nucleation Agent for Polypropylene within Antiaging and Rechargeable Antibacterial Performances

“…As shown in Figure e, the XRD patterns of neat PP show five main characteristic diffraction peaks at around 13.87, 16.62, 18.21, 20.80, and 21.52°, corresponding to the crystal planes (110), (040), (130), (111), and (131) of PP. They are the typical diffraction peaks of PP crystalline in α form . Around 2θ = 16.2°, a characteristic diffraction peak of the β-crystalline phase (300) was observed .…”

“…They are the typical diffraction peaks of PP crystalline in α form. 34 Around 2θ = 16.2°, a characteristic diffraction peak of the β-crystalline phase (300) was observed. 11 Furthermore, the intensity of the βcrystal peak increased with the NBT content, indicating that NBT can induce the formation of partially β-crystallized polypropylene.…”

Enhancing Crystallization and Toughness of Wood Flour/Polypropylene Composites via Matrix Crystalline Modification: A Comparative Study of Two β-Nucleating Agents

“…The detailed non-isothermal crystallization kinetic parameters for WF/PP, WF/ PP-TMB 0.3 and WF/PP-WBG 0.3 are listed in Table 1. The value of n strongly depends on the nucleation and crystal growth, and k represents the crystallization rate [38]. Values of n for the three samples at all cooling rates varied between 2.49 and 3.42, which was attributed to a heterogeneous nucleation followed by three-dimensional growth of crystallites [39,40].…”

β-Nucleated Polypropylene: Preparation, Nucleating Efficiency, Composite, and Future Prospects

“…Synergistic materials with β-nucleating agents include MWNTs [ 151 ]; illite [ 56 ]; calcium sulfate whiskers [ 152 ]; nano-silica particles [ 153 , 154 ]; the PA66 used in sandwich-assembly interlayer PP [ 155 ]; TPE/calcium carbonate [ 156 ]; the polyhedral oligomeric silesquioxane (POSS) amide group hydrogen bond reaction [ 157 ]; hydrotalcite (HT) [ 158 ]; and even new nanomaterials such as Mxene [ 159 ]. β-nucleating agents can maintain better performances in the system via their synergistic effect with different materials.…”