POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 31
·期 10
·2239-2249
·
IF 2.578
Qiling Zong,Ailing Xu,Kun Chai,Yanhua Zhang,Yongming Song
Green and renewable foaming poly(lactic acid) (PLA) represents one of the promising developments in PLA materials. This study is the first to use the lignin graft PLA copolymer (LG-g-PLA) to improve the foamability of PLA as a biobased nucleating agent. This agent was synthesized via ring-opening polymerization of lignin and lactide. The effects of LG-g-PLA on cell nucleation induced by the crystallization, rheological behavior, and foamability of PLA were evaluated. Results indicated that LG-g-PLA can improve the crystallization rate and crystallinity of PLA, and play a significant nucleation role in the microcellular foam processing of PLA. LG-g-PLA improved the foam morphology of PLA, obtaining a reduced and uniform cell size as well as increased expansion ratio and cell density. With the addition of 3 wt% LG-g-PLA content, the PLA/LG-g-PLA foams increased the compressive strength 1.6 times than that of neat PLA foams. The improved foaming properties of PLA via a biobased nucleating agent show potential for the production and application of green biodegradable foams.
研究领域:
材料科学
·
生物工程
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2014
·Vol. 71
·期 6
·1331-1347
·
IF 1.491
Yuan Mingwei,He Zhengguo,Li Hongli,Jiang Lin,Yuan Minglong
Ring-opening polymerization of l -lactic acid O -carboxyanhydride was catalyzed by 4-dimethylaminopyridine in the presence of polyols pentaerythritol (PER) or dipentaerythritol (DPE). A high yield and relatively high molecular weight of 4- or 6-arm star PLA were obtained. The reaction was observed to be conducted easily and controllably. NMR analysis revealed that the end of the star PLA chain is a hydroxyl group and the central core is a PER or DPE group. The crystallinity of star PLA is lower than that of linear PLA. The crystallinity of 4-arm star PLA is lower than that of 6-arm PLA. Compared with that of 4-arm star PLA, the molecular arrangement of 6-arm star PLA may be relatively more regular.
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
ADVANCED POWDER TECHNOLOGY
·
2021
·
IF 4.833
Yue Xu,Yong Qiu,Chentao Yan,Lubin Liu,Miaojun Xu,Baoti Xu,Bin Li
In engineering application area, it has always been a challenge to simultaneously improve flame-retardant performance and crystallization rate of polylactic acid (PLA) biomaterials, thus restricting their extensive application. In this work, a multifunctional additive (4,4′-(phenylphosphoryl)bis(piperazine-4,1-diyl))bis(diphenylphosphine oxide) (PDPO) was successfully synthesized and used to fabricate flame retardant PLA biocomposites. The crystallization behavior, fire safety, mechanical properties and flame retardant mechanisms of PLA biocomposites were studied in detail. The results indicated that PDPO notably improved the crystallization rate and crystallinity of PLA biocomposites. When 4 wt% PDPO was incorporated, PLA/PDPO biocomposites successfully passed UL-94V-0 grade and their LOI values were improved from 19.0% of pure PLA to 29.4%. The introduction of PDPO promoted the premature degradation and carbonization of PLA substrate, and inhibited the transesterification of the PLA during thermal pyrolysis process. Besides, PDPO decomposed and produced the Ph and PO , which efficiently exerted the free radical trapping effect in vapor phase. Therefore, the spread of fire for PLA/PDPO was declined and even self-extinguished. Meanwhile, the low addition of PDPO presented little effect on the mechanical properties of PLA composites. This flame retardant PLA biocomposites showed broad application prospects in emerging fields such as electronic devices, automobiles, and 3D printing materials.
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
Advanced Energy and Sustainability Research
·
2021
·Vol. 3
·期 1
·2100146
·
IF 0
Deyu Liu,Xiuyu Chen,Yuepeng Qiao,Yang Zhou,Yongbo Kuang
Oxide-based photoelectrodes for solar water splitting have gained growing attention because of their decent stability and cost-effectiveness. Particularly, α-SnWO 4 has been regarded as a potential next-generation light absorbing material due to the predicted favorable bandgap of 1.9 eV. Herein, the investigation and amelioration of the crystallinity as a performance dominating factor to the α-SnWO 4 -based photoanode are demonstrated. The improvement is attributed to a unique crystallization process induced by the formation of oxygen vacancies in the reductive atmosphere at 500 °C. The sample exhibits notably enhanced visible-light absorption and an improved charge transport property. Electrochemical measurements reveal a cathodic shift of the flat-band potential, corresponding to the impacted band position. The photocurrent is enhanced from 0.03 to 0.42 mA cm −2 (AM1.5, 1.23 V RHE ). Such a new treatment can be used as an effective tool for developing α-SnWO 4 into efficient photoelectrocatalytic (PEC) materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
Catalysts
·
2020
·Vol. 10
·期 12
·1480
·
IF 3.52
Wei Guo,Libin Yang,Jinghao Lu,Peng Gao,Wenjing Li,Zhiying Feng
To effectively improve photocatalytic activity, the morphology and crystallinity of semiconductor photocatalysts must be precisely controlled during the formation process. Self-aligned Nb2O5nanotube arrays have been successfully fabricated using the electrochemical anodization method. A novel growth mechanism of Nb2O5nanotubes has been proposed. Starting from the initial oxidation process, the “multi-point” corrosion of fluoride ions is a key factor in the formation of nanotube arrays. The inner diameter and wall thickness of the nanotubes present a gradually increasing trend with increased dissociative fluorine ion concentration and water content in the electrolyte. With dehydroxylation and lattice recombination, the increased crystallinity of Nb2O5represents a reduction of lattice defects, which effectively facilitates the separation and suppresses the recombination of photo-generated carriers to enhance their catalytic degradation activity.Keywords:Nb2O5;nanotube;growth mechanism;crystalline;photocatalysis
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2025
·
IF 5.1
Panpan Yang,Yifei Wu,Kunxin Wang,Sheng Lu,Yuemiao Zhang,Junxi Wan,Kun Wu,Jun Shi
In order to investigate the influence of intermolecular interactions on polymer crystallization, a series of liquid crystal polyesters with high thermal conductivity (B-LCPs) were synthesized. These were synthesized using biphenyl diols and various dicarboxylic acids as raw materials, employing a “one pot” melt polycondensation method. The λ value of B-LCP4 reaches 0.462 W (m K)−1, marking an enhancement of 135.8% in comparison to that of B-LCP3, which is 2.3 times greater than that of traditional thermoplastics. The diffraction peak of B-LCP4 at 2θ = 27.4° indicates the formation of a π–π stacking structure and crystallinity around 58%. B-LCP4 exhibited significant melting peaks and weak cold crystallization during the second heating scan, which indicates the crystal phase becomes more integrated and regular. Furthermore, the T5%, Tmax and residual carbon at 800 °C of B-LCP4 were 387.7 °C, 422.2 °C and 15.4%, respectively. The augmented thermal stability of B-LCP4 is ascribed to the delocalization of π-electrons along the backbone, which facilitates a planar conformation. The findings indicate that the π–π stacking interaction can enhance the crystallinity of polymers, subsequently improving their thermal conductivity.
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
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Qi You,Jun Zhu,Luomeng Chao,Hai Zhang,Sihua Ha
Controlling the crystallization of gallium oxide (Ga 2 O 3 ) crystal as well as intrinsic defects (oxygen vacancies) are crucial steps in obtaining high-quality material and elucidating how defects affect semiconductor properties . Gallium oxide hydroxide (GaOOH) was firstly synthesized via the reaction of gallium nitrate (Ga(NO 3 ) 3 ) with different alkalis (Urea, NH 3 ·H 2 O, Na 2 CO 3 and NaOH) using the precipitation technique. Then, Ga 2 O 3 powder was obtained by adding carbon powder as reducing agent at the calcination stage. The β-Ga 2 O 3 powder prepared by NH 3 ·H 2 O were found to have the best crystallization as analyzed by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Meanwhile, the photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS) results combined with the first-principles calculation indicate that the Ga 2 O 3 powder made by NH 3 ·H 2 O also has the least intrinsic oxygen vacancies .
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Xuan Fei,Yingjie Wang,Penglei Guo,Jinggang Wang,Guyue Wang,Guangming Lu,Weiwei Zhao,Xiaoqing Liu
Polyethylene terephthalate (PET) is one of the most widely used polymers for beverage packaging and fibers, with antimony-based catalysts currently dominating its synthesis. However, concerns about potential safety hazards associated with antimony leaching necessitate the development of environmentally benign catalysts free from heavy metals. In this work, we report the first-time utilization of Ti3C2Tx MXene as a polycondensation catalyst of PET. The intrinsic viscosity of Ti3C2Tx MXene-catalyzed PET could reach 0.78 dL/g within 2.1 h, which demonstrated a superior catalytic efficiency compared to antimony trioxide (Sb2O3). Moreover, Ti3C2Tx MXene exhibited a satisfactory performance not only in PET synthesis but also in the production of polypropylene terephthalate (PPT) and polybutylene terephthalate (PBT), thereby confirming its universality in polyester catalysis. The catalytic activity of Ti3C2Tx MXene in polycondensation reactions was attributed to the presence of strong Lewis acid sites, as supported by surface examinations and computational studies. Notably, Ti3C2Tx MXene-catalyzed PET exhibited satisfied crystallizability, as confirmed by the short crystallization half-time of only 6.9 s at 185 °C, signifying a high crystallization rate. This work highlights the potential applications of this thriving 2D material in polyester catalysis and, more importantly, provides a new perspective for the exploration and design of efficient and environmentally friendly catalyst/nucleation agents for polyester synthesis.
研究领域:
材料科学
·
催化化学
·
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
Jinli Zhao,Juan Li,Qingbai Chen,Mengwei Yang,Yongkang Li,Hong Li,Yuzhong Zhang,Jianyou Wang
The influence of crystallization behavior on membrane structure and performance has been extensively studied in many membrane fields. Some studies of proton exchange membranes used in fuel cells have involved the influence of crystallization. However, crystallization of ion exchange membranes (IEMs) used in electrodialysis (ED) has been rarely studied. Co-ion leakage in ED process is adverse, but there have been few mechanism studies regarding how co-ions cross IEM surfaces on the concentration chamber side and migrate into the dilution chamber to reduce current efficiency. Polyvinylidene fluoride is a kind of good crystalline material. In this study, sodium dodecyl benzene sulfonate was introduced as the functional material , with polyvinylpyrrolidone (PVP) as the hydrophilizing agent. They were blended to prepare cation exchange membranes (CEMs). Amorphous PVP was used to regulate membrane crystallization behavior. The results showed that, when the ion exchange capacity is basically equal, surface roughness of the prepared crystalline CEMs was low and the structure dense. The ED efficiency significantly surpassed amorphous CEMs. The co-ion leakage of amorphous CEMs was greater than those of crystalline CEMs due to the rough and non-dense surfaces of amorphous CEMs. However, after densification modification, although surface resistance increased, co-ion leakage was effectively suppressed. Combining simulation and theoretical analysis, it was presumed that dense membrane surfaces on the concentrated chamber side was very important for suppressing co-ion leakage. This study on the influence and mechanism of crystallinity and co-ion leakage was helpful for optimizing CEM mass transfer and improving current efficiency.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
GIANT
·
2024
·
IF 5.4
Hanxu Zhu,Han Hu,Qingyang Luan,Chen Lin,Juanfang Xu,Jinggang Wang,Wu Bin Ying,Jin Zhu
Improving the heat resistance of bio-based and biodegradable polyesters is of great significance to extend their applications. Herein, N,N’-trans-1,4-cyclohexane-bis(pyrrolidone-4-methyl carboxylate) (T-CBPMC) was prepared through efficient Michael-addition reaction between dimethyl itaconate and trans-1,4-cyclohexanediamine. The obtained T-CBPMC was copolymerized into aliphatic poly(butylene succinate) (PBS), and a series of PBSPs copolymers with T-CBPMC (BP) molar percentages between 41−80 mol % and weight average molecular weight ( M w ) values ranging between 5.77*10 4 and 6.67*10 4 g/mol were prepared. BP units efficiently facilitated the melting temperature (203-251 °C) and isothermal-crystallization rate (t 1/2 < 20 s) of PBSPs, endowing the highest heat resistance among commercial biodegradable polyesters, which helps maintain stable in pasteurization, high-temperature disinfection, and microwave environments. Moreover, these copolymers displayed remarkable mechanical, gas barrier properties and degradability. PBSP40-PBSP60 obtained high elastic modulus (335–872 MPa) and tensile strength (24.7–31.5 MPa), and good toughness simultaneously. Multiple-ring structures and large steric hindrance of BP units resulted in superior O 2 barrier performance than that of non-degradable PET films. Importantly, the PBSP copolyesters showed obvious degradation in water environments and relatively better enzymatic degradation. It was interesting to find that even with 70 % of the BP units, the PBSP copolyesters still retained hydrolysis ability. The resulting PBSP copolyesters open the way for alternative candidates of biodegradable packaging materials with rapid crystallization, high heat-resistance and gas barrier.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Polymer Chemistry
·
2024
·Vol. 15
·期 25
·2590-2597
·
IF 4.1
Huixuan Xu,Weigang Sun,Zhonglin Wei,Jungang Cao,Dapeng Liang,Yingjie Lin,Haifeng Duan
Herein, we provide details of the synthesis and characterization of a novel 2-carbon-extended diol derived from isomannide, 2,2′-((3S,3aR,6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl)bis(ethan-1-ol) and the corresponding semi-aromatic copolyester (PIeT) based on it and dimethyl terephthalate. This new polyester (PIeT) has a weight-average molecular weight of about 40 000 g mol−1. The NMR analysis showed that the isohexide unit was retained under applied conditions. DSC and WAXD analyses demonstrated that the polyester is semicrystalline.
研究领域:
材料科学
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CLAY SCIENCE
·
2021
·
IF 5.467
Dinghui Chen,Dawei Luo,Weijun Zhen,Ling Zhao
In the work, organic saponite (OSAP) was modified with dioctadecyl dimethyl ammonium chloride and saponite by intercalation reaction. Moreover, functionalized OSAP (FOSAP) was prepared with OSAP, BASF chain extender Joncryl ® ADR 4468 and p -phenylenediamine. The optimum reaction conditions of FOSAP were optimized by orthogonal experiment. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) results demonstrated that saponite had been successfully modified. Moreover, FOSAP/poly (lactic acid) (PLA) nanocomposites were prepared by melting intercalation with PLA and FOSAP. The mechanical properties, rheological behavior and crystallization properties of FOSAP/PLA nanocomposites were investigated. Mechanical properties showed that the impact strength and elongation at break of FOSAP/PLA nanocomposites reached 13.21 KJ/m 2 and 71.47%, respectively, when the amount of FOSAP in PLA was 0.3 wt%. In addition, the Cole-Cole curve showed that FOSAP had strong interfacial compatibility with PLA. Furthermore, the crystallization behaviors of PLA before and after modification during isothermal crystallization at 150 °C were investigated by Rheonaut technology for simultaneous rheology and FTIR, which demonstrated that FOSAP effectively promoted the crystallization of PLA and increased the storage modulus . Avrami equation showed that FOSAP changed the nucleation growing mode and significantly accelerated the crystallization rate of PLA, therefore the comprehensive performance of PLA was improved.
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
危险品化学品经营许可证（带存储）