Article
Polymer Science
Jiugeng Cheng, Zhenxing Zhong, Yuan Lin, Zhaohui Su, Chunyu Zhang, Xuequan Zhang
Summary: This work investigates the miscibility behavior of high molecular weight isotactic poly(1-butene) and isotactic polypropylene blends using AFM-IR technique. It is found that the two polymers partially miscible under certain conditions, and the content of polypropylene in each phase can be determined using a quantitative analysis method. The phase separation kinetics and phase diagram of the blends were studied, suggesting a lower critical solution temperature-type phase behavior of PB/PP blends.
Article
Polymer Science
Hao Wu, Ying Zhao, Xia Dong, Lili Su, Kezhi Wang, Dujin Wang
Summary: This study systematically investigated the microstructural evolution of iPP film samples and found that both unstabilized and stabilized iPP exhibit chemi-crystallization, with a lower extent in stabilized iPP. The loss of amorphous region induced by UV light etching was identified as another probable factor contributing to the increased crystallinity.
POLYMER DEGRADATION AND STABILITY
(2021)
Article
Polymer Science
Przemyslaw Sowinski, Sivanjineyulu Veluri, Ewa Piorkowska
Summary: This study prepared nanocomposites of isotactic polypropylene with fibrillated PTFE and investigated their crystallization behavior and resulting structure under high pressure. It was found that the addition of fibrillated PTFE increased the crystallization peak temperature of polypropylene and formed a fine-grain structure. This suggests that fibrillated PTFE can promote the crystallization of polypropylene under high pressure.
Article
Polymer Science
Ziwei Lai, Nan Zheng, Ziying Liang, Yuanjie Wang, Hui Niu, Ming-Sheng Ji, Bo Ni, Xiang Huang, Xing Ouyang, Xiaoguang Li, Bernard Lotz, Yan Cao
Summary: The research demonstrates the presence of three-dimensional helical chain assembly in isotactic polypropylene under 2D confinement, with integrated assembly observed in both alpha- and gamma-phase crystals. Additionally, two unit-cell orientations of the gamma-phase crystal are shown under cylindrical confinement. The formation mechanism for the radial gamma-phase crystals is explained by the kinetic favorability of alignment with the rod long axis.
Article
Polymer Science
Karen Van Kets, Justien Jacques, Laurens Delva, Kim Ragaert
Summary: The study evaluates the thermal and morphological stabilization of three compatibilizers during the mechanical recycling of polymer blends. The results show that although the degradation of the blends is low during multiple processing, the core stability depends on the initial stability of all components. The thermal stability of the matrix-based grafted compatibilized blend is the most favorable across the five extrusions.
JOURNAL OF APPLIED POLYMER SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Aboulfazl Barati, Pixiang Wang, Shaoyang Liu, Erfan Dashtimoghadam
Summary: Plastics were developed to change our world for the better, but plastic pollution has become a serious global environmental crisis. This work presents an in-depth analysis of the non-isothermal crystallization kinetics of recycled polyethylene terephthalate (rPET) and recycled polypropylene (rPP) blends. The study investigates the effect of pyromellitic dianhydride (PMDA) on crystallization kinetics and phase morphology of the blends. The findings have significance for the recycling/upcycling of thermoplastics through non-isothermal fabrication processes.
Article
Polymer Science
Liyuan Liu, Ying Zhao, Chunbo Zhang, Zhiyuan Dong, Kezhi Wang, Dujin Wang
Summary: The research investigated the impact of the morphological characteristics of N,N'-dicyclohexylterephthalamide (DCHT) on the polymorphic composition of isotactic polypropylene (iPP), showing that small-sized DCHT crystals have a greater influence on the formation of beta-crystals.
Article
Polymer Science
Felix A. Wenzel, Hannes Welz, Kasper P. van der Zwan, Sebastian Staeter, Klaus Kreger, Richard Hildner, Juergen Senker, Hans-Werner Schmidt
Summary: This article presents a method to control the solid-state morphology of semiconducting polymers by using supramolecular nucleating agents, which achieve high nucleation efficiencies. These agents have highly regularly arranged donor-acceptor interactions, do not induce trap states, and are beneficial for film stability.
Article
Polymer Science
E. Raghuram, Ajay Singh Panwar
Summary: Using molecular dynamics simulations, this study investigated chiral transitions in an isolated isotactic polypropylene chain on a nucleating agent substrate during the early stages of ordering. The results showed that selective stabilization of helical segments was more efficient when selecting helices from extended-coil conformations compared to coiled segments.
Article
Materials Science, Characterization & Testing
Qiang Wang, Shiqi Xie, Zhe Hua, Hui Niu
Summary: 4-Furfuryloxymethylstyrene (S-f) grafted isotactic polypropylene (iPP-g-S-f) was prepared by melt grafting reaction. The crystallization temperature of iPP after grafting increased and the crystallization rate was accelerated, resulting in smaller crystal morphology. The introduction of a small amount of S-f groups reduced the surface free energy of the crystals.
Article
Polymer Science
Enrico Carmeli, Gottfried Kandioller, Markus Gahleitner, Alejandro J. Muller, Davide Tranchida, Dario Cavallo
Summary: The crystallization kinetics of PE/PP blends under processing-relevant cooling conditions were investigated, revealing an inversion point in the crystallization order of the two polymers that can be tuned by employing different types of PP. The validity of the results shown by CCC diagrams was confirmed through ex situ morphological and wide-angle X-ray diffraction experiments, demonstrating the importance of knowing and controlling the type of components in blends obtained from recycling.
Article
Chemistry, Multidisciplinary
Laszlo Jozsef Varga, Akos Gorbe, Tamas Barany
Summary: In this study, four different grades of amorphous poly-alpha-olefin (APAO) were used to increase the toughness of drawn polypropylene (PP) tapes. The presence of APAOs facilitated the movement of PP molecules, reducing the work of drawing and increasing the melting enthalpy of the drawn specimens. The APAO with the highest molecular weight and low crystallinity level showed the greatest improvement in both tensile strength and strain-at-break, and this blend was used to produce continuously drawn tapes on a stretching line, exhibiting improved toughness.
Article
Crystallography
Xingyuan Diao, Xiaonan Chen, Shihao Deng, Hongwei Bai
Summary: In this study, trace amounts of epoxy-functionalized small-molecule modifiers were introduced into enantiomeric blends during reactive melt-blending to enhance the formation of stereocomplex-type polylactide (SC-PLA). The results showed that the in situ generation of multi-arm stereo-block PLA copolymers significantly improved SC formation, even with only 0.5 wt% modifiers. The unique copolymers acted as compatibilizers, suppressing the separation of the alternately arranged PLLA/PDLA chain segments in the molten state. Furthermore, the generation of these copolymers did not significantly increase the melt viscosity of the blends, suggesting new opportunities for high-throughput processing of SC-PLA materials.
Article
Polymer Science
Liyuan Liu, Wenhong Yang, Xinyan Chen, Ying Zhao, Xia Dong, Alejandro J. Mueller, Dujin Wang
Summary: We investigated the epitaxial crystallization of S-nucleated isotactic polypropylene with minor topographic modification at the interface caused by the inclusion of an ethylene comonomer. Experimental results showed that the amount of ethylene comonomer reduced the fraction of S-crystal (KS) due to the decreased S-nucleation ability and growth rate of the S-crystal. Molecular mechanics simulation revealed that the topographic modification weakened the intermolecular interactions, affecting the epitaxial nucleation and growth kinetics. This study provides insights into the control of polymorphism through the design of nucleation and growth interfaces.
Article
Materials Science, Characterization & Testing
Xiang Liu, Lin Zou, Baobao Chang, Honghui Shi, Qingqing Yang, Kaichang Cheng, Taolin Li, Konrad Schneider, Gert Heinrich, Chuntai Liu, Changyu Shen
Summary: The crystallization behavior of oriented isotactic polypropylene during solid-state stretching was studied using in-situ wide-angle X-ray scattering. Results indicated that stretching induced crystallization is influenced by the stretching direction, Hencky strain, and amorphous phase orientation. The high Pearson correlation coefficient suggests that the crystallization process originates from the orientation of the chain network during stretching.
