CONSTRUCTION AND BUILDING MATERIALS
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2025
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IF 8
Yan Li,Yongcai Tian,Yuyao Zhong,Xiangrui Zeng,Wenqian Zhao,Longxiang Zhang,Haoyuan Song,Yuwei Liang,Ming Yan,Shiji Jiang,Jun Xie
This study reports the green synthesis of ammonium polyphosphate-grafted lignin (APP@Lig) without organic solvents. The synthesis employed ammonium dihydrogen phosphate, urea, and phosphoric acid through nucleophilic substitution and polycondensation. Piperazine pyrophosphate (PAPP) and APP@Lig were mixed at a 3:1 mass ratio and added to a high-density polyethylene (HDPE)/polyolefin elastomer (POE) composite system (PEPO) as flame retardants. With 30 wt% total flame retardant content, the composite achieved a UL-94 V-0 rating and a limiting oxygen index (LOI) of 28.9 %. Cone calorimetry confirmed that the addition of APP@Lig reduced heat release significantly. Compared with pure PEPO, the composite showed 36.3 % lower total heat release (THR) and 82.9 % lower peak heat release rate (pHRR). The peak CO₂ release rate also decreased by 0.4 g·s⁻¹ . In addition, the fire performance index (FPI) increased by 76.5 % compared with the system containing only 30 % PAPP, indicating improved fire safety. The composite showed excellent UV resistance (UPF 44.31) due to lignin’s aromatic structures and phenolic hydroxyl groups. Overall, this work introduces a practical strategy for combining inorganic and bio-based flame retardants to enhance both flame retardancy and weather resistance in HDPE-based composites.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2024
·
IF 3.8
Kezhen Qian,Wenmin Tian,Zixu Yang,Jing Xu,Huihua Pan,Lijie Yin,Dezhen Chen
The catalytic upcycling of end-of-life polyethylene by using hierarchical zeolites has garnered attention. Fine-tuning these zeolites’ micromesoporous structure and acidity is crucial for process efficiency, which requires a comprehensive understanding of their impact on polyethylene cracking. The impact of the mesoporosity and acidity of aggregated hierarchical HZSM-5 zeolites on high-density polyethylene (HDPE) vapor cracking was studied. The results indicated that the hierarchical structure enhanced accessibility to internal acid sites, facilitating monomolecular cracking and aromatization. Intercrystalline mesopores additionally heightened the alkylated aromatic yields. The Si/Al ratio shows a positive correlation toward the C5+ aliphatic hydrocarbon cracking, which boosts the formation of C2–C4 olefins and BTEX (benzene, toluene, ethylbenzene, and xylene). However, the presence of mesopores also yielded more heavy aromatics, thus increasing the risk of coking. The role of acid sites spatial distribution was investigated by poisoning the acid sites in micropores via pre-coking. The results indicated that the cracking of HDPE vapor occurred on the external acid of the zeolite, followed by the subsequent C5+ aliphatic hydrocarbon cracking on the mesopore and micropore to form aromatics and C1–C4 products. The formation of BTEX mainly occurred in the micropore, while the heavier aromatics and other alkylated benzenes were formed in the mesopore. The results of this study highlighted the importance of a proper hierarchical structure and acid site distribution in zeolites for effective and stable polyolefin cracking.
研究领域:
化学工程
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催化材料
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ACS Applied Polymer Materials
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2022
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IF 4.855
Yuming Chen,Wei Li,Letian Zhang,Chunlin Ye,Gan Tao,Congjing Ren,Binbo Jiang,Jingdai Wang,Yongrong Yang
In this study, tailored polyethylene reactor blends with the in situ embedding of a weakly entangled ultra-high-molecular-weight polyethylene (UHMWPE) were synthesized by the polyhedral oligomeric silsesquioxane modified Ziegler–Natta (ZN) catalysts using a two-stage cascade polymerization technique. Holistic improvement of strength/stiffness/toughness was realized by the common injection modeling owing to the enhanced formation of an orientated structure which was verified by the patterns of two-dimensional (2D) small-angle X-ray scattering and 2D wide-angle X-ray diffraction, as well as the fracture morphology. 30 wt % of the less entangled UHMWPE was successfully incorporated into the high-density polyethylene (HDPE) matrix to achieve a synchronously increased tensile strength (52.4 MPa, +97.7%), Young’s modulus (604.2 MPa, +43.6%), and impact resistance (74.4 kJ/m2, +675%), compared with those of the benchmarked HDPE. However, dissipation of a shish-kebab structure was pronounced in the depth direction of the HDPE spline reinforced with the disentangled UHMWPE. This dissipation was proved to partially sacrifice the strength and stiffness. Importantly, the impact strength is greatly enhanced (+140%) due to the cocrystallization effect of the disentangled linear UHMWPE chains with the HDPE matrix. The HDPE matrix reinforced with the weakly entangled UHMWPE presents wider gradient distribution and orientation degree distribution of oriented structures (including shish-kebab and stacked lamella) along the depth direction. Thus, the balance of strength/stiffness/toughness was synergistically improved with the wider gradient distribution of oriented structures. This in situ polymerization method with the weakly entangled UHMWPE offers a promising routine for achieving the high-performance polyethylene commodity.
研究领域:
材料科学
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聚合物工程
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2014
·Vol. 52
·期 22
·3205-3212
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IF 3.245
Zhixian Xu,Suyun Jie,Bo-Geng Li
Well-defined diblock copolymers of linear polyethylene (PE) and poly(dimethylsiloxane) (PDMS) have been synthesized through a facile route combining the thiol-ene click chemistry of vinyl-terminated polyethylene (PE-ene) and the sequential esterification reaction. The resulting diblock copolymers are characterized by 1 H NMR, FT-IR, DSC, TGA, and TEM. In addition, the PE- b -PDMS diblock copolymers have been evaluated as compatibilizers in the blends of high-density polyethylene (HDPE) and silicone oil. The morphological analysis and mechanical properties demonstrate that the compatibilized blends with low loading concentration of PE- b -PDMS display significant improvements in modulus of elasticity and elongation at break as compared to the uncompatibilized binary blends. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52 , 3205–3212
研究领域:
高分子化学
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材料科学
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Catalysis Science & Technology
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2026
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IF 4.2
Jianyi Liu,Jialei Liu,Yang Yang,Jianhao Guo,Xiaofeng Xue,Ning Zhao,Yibin Zhan,Tiedong Xie,Boping Liu,Yulong Jin
Support modification is a simple but effective method to promote olefin polymerization catalysts, which is often correlated with enhanced acidity. Here, following this rule, the bimetallic catalyst CrOx/VOx/silica for UHMWPE/HDPE in-reactor blends was modified by alumina, sulfate, and alumina/sulfate. All modified catalysts were promoted notably, with ethylene polymerization activities about twice that of the unmodified one. Similarly, NH3-TPD and FTIR-pyridine confirmed their enhanced acidity. Theoretical studies emphasized the importance of Lewis acidic Al³⁺ site, which induced geometric and electronic rearrangement of the active site, thus reducing steric hindrance and improving LUMO reactivity. Sulfation further strengthened Al³⁺ acidity, exacerbating rearrangement and lowering the insertion barrier. Contrary to expectations, the alumina/sulfate-modified catalyst—with much stronger Brønsted and Lewis acidity—was only moderately promoted. XPS, DRS UV-vis, elemental analysis, and DFT results indicate that, while modification improves metal center electron deficiency and facilitates ethylene insertion, stronger acidity also weakens the anchoring of Cr(VI) and V(V) active precursors and promotes inactive Cr(III) and V(III) species. This effect was more pronounced for the superacidic alumina/sulfate modifier, partially counteracting its promotional effect.
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POLYMERS FOR ADVANCED TECHNOLOGIES
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2022
·Vol. 33
·期 10
·3125-3136
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IF 3.348
Bin Yang,Shun Wang,Mengya Ding,Chengjun Wang,Cheng Lv,Yang Wang,Yuqing Yang,Nuo Zhang,Zhiqiang Shi,Jiasheng Qian,Ru Xia,Yirong Fang
In this study, HDPE/UHMWPE microporous films were prepared by blending UHMWPE and HDPE with DOP as the diluent via thermally-induced phase separation (TIPS) method. Morphological studies showed that the phase separation mode of the mixed systems was hardly changed in the presence of UHMWPE. Both average pore size and porosity of the blend films increased firstly and then decreased with increasing UHMWPE content. When UHMWPE content reached 1.5 wt%, both porosity and average pore size of the film reached their maximum values (with a porosity of 84.8% and an average pore size of 0.79 μm). The addition of UHMWPE was found to not only enhance the thermal stability of the HDPE/UHMWPE blend films, but also greatly reduce their thermal shrinkage rate as well as the closed cell temperature, which made the diaphragms containing UHMWPE have good prospect for the application in lithium-ion batteries (LIBs).
研究领域:
材料科学
·
能源科学
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