MACROMOLECULES
·
2019
·
IF 5.997
Yuming Chen,Peng Liang,Zhen Yue,Wei Li,Chuanding Dong,Binbo Jiang,Jingdai Wang,Yongrong Yang
Chain entanglement was very important for adjusting the processability and mechanical property of nascent ultrahigh molecular weight polyethylene (UHMWPE). So far, it is still a mystery to unravel the formation mechanism of entanglements when the ethylene polymerization is conducted by the heterogeneous catalysts. In this study, a series of weakly entangled UHMWPE was synthesized by the polyhedral oligomeric silsesquioxane/MgCl2 nanoaggregates modified Ziegler–Natta catalysts. The structure of nanoaggregates was evaluated by X-ray photoelectron spectroscopy, density functional theory simulations, and scanning probe microscope experiments, where the coordination strategy of MgCl2 and hydroxyl of POSS was investigated. These nanoaggregates presented extremely low activity on ethylene polymerization and were proved to serve as isolators for separating the active sites and growing chains. The entanglement density of nascent UHMWPE (reflected by the value of initial storage modulus G′(t=0)) was exponentially decayed with the polymerization activity of increased numbers of nanoaggregates. Importantly, this exponentially decayed effect contributed by increased numbers of POSS/MgCl2 isolators offset the rapid power function increment of entanglements upon rising the temperature, which was the essential reason for the successful synthesis of weakly entangled UHMWPE even at 85 °C. Finally, we have proposed the dependence and sensitivity of G′(t=0) (i.e., indicating the initial entanglement density of nascent polymers) on the polymerization activity, which was able to trace the formation of entanglements during polymerization through the POSS modified heterogeneous catalyst.
研究领域:
材料科学
·
高分子化学
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产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2021
·
IF 3.423
Min Huang,Huan Shi,Ning Wei,Chunhui Luo,Faliang Luo
Polyvinyl alcohol (PVA) hydrogels have drawn enormous attention but are severely limited on account of poor mechanical properties at subzero temperatures. Here, we propose a simple method to tackle this problem by incorporating chain entanglements of PVA chains and coordination bonds between Al 3+ ions and –OH groups via air-drying and soaking in Al 2 (SO 4 ) 3 solution. The multiple dynamic interactions worked in tandem to achieve outstanding mechanical performance (41.0 MPa of fracture stress and 49.9 MJ/m 3 of toughness). Meanwhile, the introduction of ions endowed the PVA hydrogel with excellent anti-freezing property (36.9 MPa of fracture stress and 51.4 MJ/m 3 of toughness at −20 ℃), superior to most anti-freezing gels at subzero temperatures. The facile synthesis and superior properties might expand the application of PVA hydrogels.
研究领域:
材料科学
·
生物材料
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Min Jiang,Bo-Wen Liu,Feng-Ming He,Qin Zhang,Ao Wang,De-Ming Guo,Hai-Bo Zhao,Li Chen,Yu-Zhong Wang
Although conventional chemical copolymerization method has shown favorable results in improving certain performance of polymers, simultaneous improvement of overall properties is hardly achieved. Here, we reported a feasible method to fabricate high-performance polymers with great overall properties by simultaneously tailoring their chemical constitution and topological conformation. We designed and synthesized a novel functional monomer with a sidechain caged structure based on phosphorus chemistry, and prepared the corresponding aliphatic polyamide as a typical representative of thermoplastic synthetic polymers. The incorporation of a sidechain caged structure enhanced the chain entanglement of the resultant polyamide, thus improved the mechanical strength by 39% and largely enhanced the heat resistance. The great processability was basically uninfluenced due to the easy dissociation of the entanglement during processing, enabling the potentially wide application fields as both fibers and engineering plastics. Furthermore, based on the free radical scavenging effect of the phosphorus-based monomer, the flame retardancy of the resultant polyamide was significantly improved. In sight of these findings, this work provides a novel method for fabricating high-performance polymers for various applications.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULAR CHEMISTRY AND PHYSICS
·
2016
·Vol. 217
·期 19
·2139-2144
·
IF 2.495
Xiuyin Zhang,Chuanzhuang Zhao,Nanping Xiang,Wei Li
Physical interaction between the microgel and the hydrogel matrix is a key issue in the rational design of microgel reinforced hydrogels. A pentaerythritol-crosslinked poly(acrylic acid) (PAAc) microgel, named Carbopol, is composited with polyacrylamide (PAAm) hydrogel. The toughness of the hydrogel is significantly improved by constructing an interpenetrating network of Carbopol and PAAm. Chain entanglements within the composited hydrogel result in a strain-hardening phenomenon and an efficient stress transfer from the PAAm matrix to the sacrificing network of Carbopol. Hydrogen bonds between PAAc and PAAm can be formed in an acidic environment, which function as reversible sacrificing bonds and further improve the stretchability of the hydrogel.
研究领域:
材料科学
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生物材料
✓ 已验证
产品关联
DOI
高影响因子
ENERGY AND BUILDINGS
·
2025
·
IF 7.1
Ranran Wu,Ziyu Wang,Junfang Chang,Sui Wang,Jie Mao
The development of thermochromic hydrogels for smart windows faces challenges in balancing optical performance, durability, and environmental adaptability. Traditional chemically crosslinked hydrogels suffer from low transmittance and structural instability during phase transitions. Herein, we propose a physical chain-entangled thermochromic hydrogel (PNA) via a one-pot synthesis of polyvinyl alcohol (PVA), poly(N-isopropylacrylamide) (PNIPAM), and polyacrylic acid (PAA). PVA provides a network framework for the temperature-sensitive phase transition of PNIPAM, enabling a rapid (5 s) switch of the hydrogel from a highly transparent state ( T lum ≈ 95 %) to an opaque state ( T lum < 20 %). By modulating PAA content, the lower critical solution temperature (LCST) is precisely tuned to 25 °C, aligning with human thermal comfort. Unlike traditional chemically cross-linked hydrogels, this physical chain-entangled hydrogel has a uniform pore structure, ensuring that the light transmittance of the hydrogel is independent of its thickness. This PNA smart window has demonstrated outstanding stability in long-term cycle tests (heating–cooling/ultraviolet aging), with a reduction in light transmittance of less than 5 %. DSC analysis and transmittance analysis show that this smart window has good frost resistance under sub-zero climate conditions (−20 °C freezing point). In the practical application simulation of PNA smart windows, it has reduced the box temperature by 10 °C compared with ordinary glass, demonstrating outstanding application potential in the field of energy-saving building materials.
研究领域:
材料科学
·
能源技术
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2023
·
IF 5.5
Gang Liu,Ronald G. Larson,Lei Li,Huan Luo,Xi He,Yanhua Niu,Guangxian Li
Polymerized ionic liquids (PILs) poly[1-(4-vinylbenzyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide] (P[VBMIM][TFSI]) covering a wide range of molecular weights are synthesized using reversible addition–fragmentation chain-transfer (RAFT) polymerization. The dependence of zero-shear viscosity on weight-average molecular weight (η0 ∼ Mwα) shows two power-law regimes corresponding to disentangled and entangled regimes with α = 1.1 ± 0.1 and 3.6 ± 0.4, as is typical for neutral entangled polymers. The entanglement molecular weight (Me,calc = 1.8 × 105 g/mol) of P[VBMIM][TFSI] estimated from the packing length p = 8.6 Å and Kuhn length b = 20 Å is consistent with the experimental result (Me,rheo = 1.6 × 105 g/mol) and is much higher than the most conventional uncharged polymers due to the bulkiness of the monomers. For entangled PIL samples, reversible strain-induced disentanglement is observed under large-amplitude oscillatory shear (LAOS) and strong strain hardening in extensional flow. The chain entanglement in high-molecular-weight P[VBMIM][TFSI] brings significant improvement in the mechanical strength and robust recoverability under cyclic stretch over that of the lower-molecular-weight, unentangled PILs, making high-molecular-weight P[VBMIM][TFSI] processable for high-performance electrolytes.
研究领域:
材料科学
·
高分子化学
·
流变学
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产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Huashuai Cui,Zetian Zhang,Qing Huang
The increasing concerns over pollution from non-degradable plastics are prompting a quest for sustainable alternatives. Polyglycolic acid (PGA), known for its good biocompatibility and high mechanical strength, faces limited applications due to its uncontrollable degradation rate. This article introduces an effective approach to enhance the shelf life of PGA by constructing a novel “ stereo-lock ” structure. Stereocomplex polylactic acid (ScPLA) is first disassembled and fixed to the amorphous region of PGA by melt spinning. Later, an annealing process enhances molecular chain mobility, leading to the reformation of ScPLA and the locking of entangled PGA amorphous molecular chains, resulting in the formation of “ stereo-lock ” configurations. Thus, molecular chain density in the amorphous area increases, which reduces the accessibility of water to ester bonds and is conducive to improving the degradation resistance of PGA. As a result, compared to pure PGA, the rate of degradation of the monofilament possessing “ stereo-lock ” structure is noticeably slower. Specifically, by the seventh day of the accelerated degradation tests, the weight loss of the PGA monofilament dropped from 61.4 % to 48.4 % in the monofilament with “ stereo-lock ”. Furthermore, the formation mechanism of the “ stereo-lock ” was confirmed through a series of investigations and analyses. The structure-property relationship between molecular chain entanglement and degradation properties of PGA was studied systematically in this study, which also offers fresh perspectives on how to control the degradation characteristics of other polymers.
研究领域:
材料科学
·
生物医学工程
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2024
·
IF 8.4
Jiandang Xue,John C. Douglin,Tong Huang,Haifei Jiang,Junfeng Zhang,Yan Yin,Dario R. Dekel,Michael D. Guiver
Poly(arylene piperidinium) (PAP) anion-exchange membranes (AEMs) are attractive platform materials currently used for anion-exchange membrane fuel cells (AEMFCs) and chain branching modifications on PAP polymer structures have recently drawn much attention for effectively regulating the membrane properties. To better understand the influence and interplay of the polymer chain entanglement and free-volume effect from various branched architectures, herein, lightly end-branched EB-PTP/TPB AEMs, using poly( p -terphenyl dimethylpiperidinium) (PTP) as the polymer backbone and bulky rigid 1,3,5-triphenylbenzene (TPB) as the branching agent, are designed and compared to previously reported random-branched RB-PTP/TPB and linear-chain PTP membranes. Intrinsic viscosity, bulk density and positron annihilation lifetime spectroscopy suggest a lesser extent of chain entanglement, but more evident free-volume elements for end-branched EB-PTP/TPB, particularly for higher branched EB-PTP/TPB-1% containing 1 mol% of TPB branching agent, compared with the random-branched RB-PTP/TPB that exhibits a more predominant chain entanglement effect. EB-PTP/TPB AEMs with increased free volume exhibit faster water sorption kinetics and slightly higher ion conductivity, but the concurrent high water sorption levels are disadvantageous to high-temperature ion transport, alkaline stability and water balance management. Even so, EB-PTP/TPB AEMs still show sufficient mechanical robustness, restricted swelling and higher alkaline stability than linear-chain PTP membranes, aided by the considerable extent of chain entanglement. This work reveals branched architecture–AEM property relationships and provides valuable insights towards branched architecture design.
研究领域:
材料科学
·
能源科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Shuyao Ye,Jincheng Dai,Wei Li,Yao Yang,Zhengliang Huang,Jingdai Wang,Yongrong Yang
The reduction in the entangled state of the nascent ultrahigh-molecular-weight polyethylene (UHMWPE) is of fundamental importance to enhance its processability and mechanical properties. However, it remains a challenge to retard the formation of entanglements during polymerization above 60 °C because the chain propagation rate is notably higher than the chain crystallization rate. Herein, we present a feasible method for synthesizing the weakly entangled polyethylene via nitrogen microbubble-assisted polymerization. The mass transfer of ethylene inside the growing polyethylene particles is found to dominate the chain propagation process, which is influenced by the nitrogen bubble size. The contact/interval time (10–3 s) between the microbubbles and the particles, observed by a high-speed camera, appears several orders less than the chain propagation time. Consequently, such frequent contact/separation instantly blocks/recovers the reactant transfer on the solvent–particle interphase, causing an intermittent “dormancy effect” to retard the chain propagation and facilitate the chain crystallization. Therefore, the less entangled polyethylene is synthesized at a relatively high activity.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today
·
2025
·
IF 22
Xianmei Huang,Weiqiang Chen,Xuan Zhou,Dhandapani Kuzhandaivel,Shuqiang Peng,Longhui Zheng,Herfried Lammer,Xiaohong Ding,Zixiang Weng,Lixin Wu
Vat photopolymerization (VPP) elastomers often suffer from poor tear resistance due to the limited ability of entangled polymer chain segments formed by free radical curing to guide crack propagation. While elastomers prepared through photo-thermal dual-curing mechanisms with highly entangled polymer chains have improved tensile properties, their permanent radical‑derived crosslinks restrict toughness optimization. Here, ureidopyrimidinone (UPy) moieties were incorporated in dynamic polyurethane acrylate, introducing quadruple hydrogen bonds as sacrificial physical crosslinking points to achieve full molecular chain extension. This strategy avoids permanent radical-derived chemical crosslinks by incorporating UPy-based reversible interactions, leading to dual improvements in crack propagation guidance and tensile performance. Unlike conventional methods relying on monomer to reduce viscosity for vat photopolymerization compatibility, the hydrogen bond-rich high-viscosity oligomer developed in this work supports direct monomer-free printing through linear scan-based vat photopolymerization (LSVP) system. Corresponding results demonstrate that 3D-printed parts achieved a tensile strength of 40.31 MPa, elongation at break of 992 %, and crucially, fracture energy reaching 189.42 kJ m −2 , which comparable to thermoplastic polyurethane. Moreover, the synergistic effect of chain entanglement and reversible bonding imparts thermoplastic-like self-healing and recyclability. This work offers a new strategy for developing photopolymerizable elastomers with integrated strength, tear resistance, and reprocessability, advancing their potential in flexible electronics and functional 3D printing.
研究领域:
高分子材料
·
生物医学工程
·
柔性电子
·
功能3D打印
·
再生医学
·
组织工程
·
材料科学
·
生物力学
✓ 已验证
产品关联
DOI
高影响因子
Bioactive Materials
·
2025
·
IF 20.3
Wenzhong Cao,Xianchi Zhou,Wenbin Dai,Zihao Zhu,Zuolong Liu,Kexin Chen,Yu Yan,Hengshuai Bao,Jian Ji,Peng Zhang
Hydrogel coatings have become indispensable for advanced interventional devices owing to their exceptional lubricity, antithrombogenicity, and antibacterial performance. However, clinical adoption has been hindered by the risk of polymer embolism resulting from coating delamination in vascular systems. Herein, we report an embolism-free hydrogel coating strategy based on chain-entanglement-mediated topological gelation to address this limitation. Through an interface-regulated polymerization process, we fabricate a robust zwitterionic hydrogel coating stabilized by interfacial interlinking and enhanced polymer chain entanglement. This design delivers outstanding long-term antimicrobial and antithrombogenic properties and achieves high toughness, ultra-low friction, and wear resistance. Notably, the chain-entangled topological hydrogel exhibits a unique fail-safe mechanism: upon detachment, it undergoes spontaneous aqueous dissolution rather than forming hazardous debris. This approach can potentially reduce life-threatening complications in interventional therapies by eliminating the risk of polymer-induced embolism.
研究领域:
生物材料
·
介入医学
·
表面工程
·
心血管器械
·
抗凝血
·
感染控制
·
高分子科学
·
转化医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CELLULOSE
·
2016
·Vol. 24
·期 2
·863-870
·
IF 3.195
Chen Haizhen,Chen Jing,Teng Na,Na Haining,Zhu Jin
Residual ethanol was used as an activation agent to control the status of corn cellulose (CN cellulose) solution and thereby the morphology of CN cellulose fibers after electrospinning. A suitable amount of ethanol could combine with the CN cellulose chains to reduce their ionic absorbance, improving the migration ability of ions in the cellulose– N , N -dimethylacetamide (DMAc)/LiCl–ethanol system. As a result, the entanglement of the molecular chains of CN cellulose in solution was reduced. Excess ethanol reduced the migration ability of ions and enhanced the strong entanglement of CN cellulose in solution. By thus adjusting the status of the CN cellulose solution, the fiber morphology and diameter distribution after electrospinning could be controlled. Based on the experimental results, this approach represents an important and effective approach using ethanol as an activation and adjusting agent for CN cellulose to achieve formation of high-quality electrospun fibers.
研究领域:
高分子科学
·
材料科学
·
纤维工程
·
生物材料
·
纳米技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）