Article
Polymer Science
Sascha Stanic, Thomas Koch, Klaus Schmid, Simone Knaus, Vasiliki-Maria Archodoulaki
Summary: Blending LCB-PP and L-PP can increase the molecular weight and distribution of the polymer, improve melt strength, and enhance mechanical properties. Especially when using recycled polypropylene, this method demonstrates the potential for upcycling.
Article
Polymer Science
Chuangbi Chen, Mehdihasan I. Shekh, Shuming Cui, Florian J. Stadler
Summary: Blends of long-chain branched metallocene-catalyzed high-density polyethylenes (LCB-mHDPE) with varying concentrations of high and low molecular LCB-mHDPE were studied for their rheological behavior, revealing differences in molar mass and distribution. The high molecular LCB-mHDPE in the blends exhibited more pronounced long-chain branching behavior compared to the base materials, with thermorheological analysis indicating increased activation energies corresponding to peak functions. This suggests that details of thermorheological complexity can be used to estimate molar mass distribution in polyethylenes.
Article
Polymer Science
Menglong Xu, Jiawei Lu, Jinchuan Zhao, Linfeng Wei, Tao Liu, Ling Zhao, Chul B. Park
Summary: In this study, a series of long-chain branched polyamide 6 samples (LCB PA6s) with well-defined branch length were successfully fabricated via reactive extrusion using various linear PA6s as reactive materials. The GPC-rheology method was used to demonstrate the existence of LCB topological structure and quantitatively determine the relative branch length for three LCB PA6s. Rheological characterization showed that increasing branch length resulted in enhanced elastic response and melt strength of PA6s. Additionally, the melt foamability of these LCB PA6s was verified through batch foaming experiments with supercritical CO2 as the blowing agent, showing potential for large-scale production via continuous extrusion foaming process.
Article
Chemistry, Physical
Ning-kai Shu, Zhi-cheng Xu, Qing-tao Gong, Wang-jing Ma, Lei Zhang, Lu Zhang
Summary: This study investigates the adsorption and dilational rheological properties of branched cationic surfactant at the air-water interface in the presence of NaCl. The results show that the addition of NaCl influences the nature of the film and dilational viscosity, with a more significant impact at higher NaCl concentrations. Overall, the presence of electrolyte transforms the elastic adsorption film into a viscoelastic one.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Polymer Science
Ho Suk Ji, Geunyeop Park, Hyun Wook Jung
Summary: This study investigates the structural and rheological properties of controlled-rheology polypropylenes (CR-PPs) using pilot-scale twin-screw reactive extrusion. The effects of peroxide content and extrusion conditions on CR-PPs are prioritized. It is found that a small peroxide content gradually increases the melt index and narrows the molecular weight distribution of CR-PPs, resulting in favorable properties for the fiber spinning process. However, the mechanical properties of CR-PPs are slightly degraded due to unsaturated chain ends generated during the reactive extrusion. The study confirms that CR-PPs can be successfully applied to the melt-spinning process for staple fiber production, ensuring a more stable spinning process window.
Article
Materials Science, Multidisciplinary
Laongdaw Techawinyutham, Jiratti Tengsuthiwat, Rapeeporn Srisuk, Wiroj Techawinyutham, Sanjay Mavinkere Rangappa, Suchart Siengchin
Summary: Blending recycled PETG, LDPE, and HDPE can improve the properties of plastic wastes and reduce waste in plastic processing plants. LDPE/PETG blends show better impact resistance and flexibility, while HDPE/PETG blends enhance mechanical properties.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Biochemistry & Molecular Biology
Deyin Wang, Xiaohui Wen, Dong Zhang, Jiajun Tang
Summary: In this study, the effect of arms and shear flow on the dynamical and structural properties of the comb long-chain branched (LCB) polymer with dense arms was investigated using hybrid multi-particle collision dynamics (MPCD) and molecular dynamics (MD) methods. The results show that the LCB polymer undergoes periodic stretched-folded-stretched state transition and rotation, with the arms playing a role in stabilizing the polymer's motion. The impact induced by random and fast motions of arms and backbone decreases as the shear rate increases. The length of the arms and the conformational distribution are found to be important factors affecting the rotation period of the LCB polymer. The structural properties analysis reveals that the changes in gyration of the LCB polymer are in accordance with its rolling behavior, and the resistance to configuration expansion against the imposed flow field is stronger for the comb polymer with shorter arms. Additionally, with increasing arm length, the comb polymer transitions from linear-polymer-like to capsule-like behavior in shear flow.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Mechanics
Helmut Muenstedt
Summary: It has been shown that mechanical pretreatments of long-chain branched polymers can alter their rheological properties, with chain alignment potentially playing a role in this effect. However, the specific mechanism behind this phenomenon is not yet fully understood.
JOURNAL OF RHEOLOGY
(2021)
Article
Polymer Science
Violette Bourg, Rudy Valette, Nicolas Le Moigne, Patrick Ienny, Valerie Guillard, Anne Bergeret
Summary: The rheological behavior of linear and branched polybutylene succinate blends were investigated under different processing conditions, revealing that a higher level of branching in the blend leads to increased relaxation time and improved strain hardening during uniaxial elongation. The 50/50 wt% blend exhibited similar behavior to linear polybutylene succinate under extensional flow, indicating potential benefits for processing.
Article
Chemistry, Applied
Yue Cheng, Kexin Liang, Yifan Chen, Wei Gao, Xuemin Kang, Tianze Li, Bo Cui
Summary: This study focuses on the molecular structure changes of corn starch (CS) gels caused by different treatment temperatures and their effects on CS gel rheological and 3D printing properties. The increase in leached amylose content and short linear chains of CS increase with increasing treatment temperature, while the contents of long linear chains decrease, which influences the rheological and 3D printing properties of starch. The molecular structural changes caused by starch gelatinization are critical to its ideal rheological properties for 3D printing.
FOOD HYDROCOLLOIDS
(2023)
Article
Polymer Science
Guifa Xu, Yangke Xiao, Wen-Jun Wang, Bo-Geng Li, Pingwei Liu
Summary: This study blends CPOEs with PE-Ms to investigate the structure-activity relationship of CPOEs. The results show that the effect of LCBes on material performance is related to their chain conformation and the number of entanglements. This research provides insights into macromolecular engineering in polymer and can facilitate the development of higher-performance CPOEs or other grafted polymers.
Article
Biochemistry & Molecular Biology
Yesmine Fourati, Quim Tarres, Marc Delgado-Aguilar, Pere Mutje, Sami Boufi
Summary: In this study, the mechanical performance of PBAT/TPS blends was enhanced by incorporating cellulose nanofibrils (CNFs), with optimal performance achieved at 8 wt% of CNFs. The addition of CNFs resulted in a more uniform distribution of TPS nodules within the PBAT matrix, leading to improvements in material properties.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Multidisciplinary Sciences
Yu Zhu, Hanqiu Jiang, Weiwei Wu, Xiao-Qin Xu, Xu-Qing Wang, Wei-Jian Li, Wei-Tao Xu, GengXin Liu, Yubin Ke, Wei Wang, Hai-Bo Yang
Summary: This article presents a novel type of polymer, rotaxane-branched dendronized polymers, with tunable thermal and rheological properties. These polymers have reversible thickness modulation ability and can serve as attractive platforms for the construction of smart polymeric materials.
NATURE COMMUNICATIONS
(2023)
Article
Polymer Science
Tao Liu, Weidang Duan, Jialin Zhang, Qiuping Li, Jian Xu, Jie Wang, Yongchun Qin, Rong Chang
Summary: This study evaluated the effects of the source and admixture of aged asphalt on the rheological properties of reclaimed asphalt binders. Relative viscosity, relative rutting factor, and relative fatigue factor were used as evaluation indicators. The results showed that the viscosity, rutting factor, and fatigue factor of the reclaimed asphalt binder increased with the addition of aged asphalt, but the effect of the source and admixture of aged asphalt could not be assessed. Additionally, the relative viscosity and relative rutting factor decreased linearly with increasing temperature under high-temperature conditions, while the relative fatigue factor increased linearly with increasing temperature under medium-temperature conditions. These findings suggest that the evaluation method used in this study can assess the effects of virgin asphalt and aged asphalt on the rheological properties of the reclaimed asphalt binders.
Article
Polymer Science
Ruixue Niu, Zhening Zheng, Xuedong Lv, Benqiao He, Sheng Chen, Jiaying Zhang, Yanhong Ji, Yi Liu, Liuchun Zheng
Summary: The introduction of pentaerythritol as a branching agent in the synthesis of poly(butylene dodecanedioate) (PBD) can improve the melt strength and blow-molding properties of the polymer. The introduction of a small amount of pentaerythritol generates branching and crosslinking structures, leading to improved impact strength and tensile modulus. The PER-branched PBDs also exhibited enhanced crystallization ability and shear-thickening behavior.
