POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 6
·1291-1299
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IF 2.578
Jun Jiang,Shuangqiao Yang,Linhuan Li,Shibing Bai
With the continuous development of the electronics industry, in order to meet the requirements of electronic equipment to reduce the size and increase power consumption, the development of high thermal conductivity materials is crucial. In this study, thermally conductive polylactic acid (PLA) composites were prepared by constructing graphene and alumina (Al 2 O 3 ) hybrid filler network, and it was further successfully used in additive manufacturing. Due to the synergistic effect of Al 2 O 3 and graphene, the resulting composite achieved the thermal conductivity of 2.4 Wm −1 K −1 with 70 wt% Al 2 O 3 and 1 wt% graphene, which are superior to data reported in the literature in the same filler condition. The Al 2 O 3 and graphene hybrid filler network reduced the agglomeration of graphene and the thermal contact resistance between the fillers, thereby leading a faster cooling rate. Furthermore, the obtained thermally conductive PLA composite has good thermal stability at a normal temperature. The PLA composite powder obtained by the cryogenic pulverization can be used in the laser sintering additive manufacturing process to prepare a heat conductive material with a complicated shape.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 10
·2239-2249
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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.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 11
·2676-2686
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IF 2.578
Yingying He,Xinyue Liu,Xiaojun Qi,Yupeng Guan,Shuai Li,Hongxia Liu,Li Zhou,Chun Wei,Chuanbai Yu
Both poly(methyl methacrylate) (PMMA) and polystyrene (PS) have excellent transparency, but a blend of the two typically has low mechanical properties and poor transparency owing to phase separation. Herein, oil-in-water Pickering emulsion gel technology was combined with the hot pressing process to prepare cellulose nanofibrils (CNFs) reinforced PMMA/PS binary blend composite film materials (CNFs/PMMA/PS). The CNFs/PMMA/PS composites with a pebble-shaped structure had a unique three-dimensional crosslinked network structure and endowed the composite film with better thermal stability, and excellent transparency and mechanical properties. Particularly, the derivative thermogravimetry and differential scanning calorimetry results revealed that the compatibility between the PMMA and the PS phases in the composite film is remarkably improved. The optimal tensile strength (58 MPa) and maximum strain (4.2%) were obtained when the content of CNFs was 52%, which represented approximately 3-fold and 2-fold improvements, respectively, than those of the PMMA/PS blend films. Moreover, the C-CNFs/PMMA/PS composite films maintained an excellent light transmittance of approximately 80% in the wavelength range of 600 to 800 nm. The facile preparation method is proposed to achieve an excellent dispersion of unmodified CNFs in hydrophobic and binary polymer mixture, which constitutes a new approach for using CNFs to enhance the high performance of polymer materials.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 9
·1980-1993
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IF 2.578
Yanjiao Chang,Qiang Zhou,Luping Ning,Yunhong Liang,Lei Ren,Luquan Ren
The poly- N -isopropylacrylamide intelligent hydrogel actuators with high mechanical strength and efficient temperature responses were successfully prepared via molding and three-dimensional (3D) printing. Addition of nanofibrillated cellulose (NFC) effectively improved the crosslinking density and viscosity of hydrogels, enhancing the mechanical strength and 3D printable property. Based on sufficient polymerization on interface, bilayer hydrogel actuator prepared via molding exhibited efficient bending/unbending deformations. Bending degree in poikilothermy temperature ranging from 25°C to 55°C was higher than that in constant temperature of 55°C. Inspired by the rheology regulation of NFC, 3D printing intelligent hydrogel actuators with NFC content of 10 mg/mL were polymerized efficiently by ultraviolet irradiation. Self-driven deformation characteristics of 3D printed intelligent hydrogels actuators were regulated via printing parameters including angle, width and length ratio and filling rate of the layered network structure model. The prepared hydrogel material system with molding and 3D printing ability provided material candidates for design and preparation of intelligent soft actuator and robot.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 8
·1865-1874
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IF 2.578
Lu Li,Xia Liao,Xingyue Sheng,Pan Liu,Zengheng Hao,Leilei He,Geng Qin
In this study, the hyperbranched polyester were successfully grafted onto graphene oxide (GO). The mechanical performance and curing kinetics of epoxy resin (EP), EP/ graphene oxide (EP/GO), and EP/ hyperbranched polyester grafted GO (EP/GO-B) were investigated by means of mechanical tests and differential scanning calorimetry (DSC). Results revealed that the presence of GO lowered the cure temperature and accelerated the curing of EP, and the addition of GO-B exhibited a stronger effect in accelerating the cure of EP compared with GO. Activation energies were calculated using Kissinge r approach, and Ozawa approach, respectively. Results revealed lowered activation energy after the addition of GO or GO-B at low degrees of cure, indicating that GO had a large effect on the curing reaction. The presence of GO facilitated the curing reaction, especially the initial epoxy-amine reaction. Moreover, GO-B exhibited better performance. Related mechanism was proposed.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 8
·1776-1782
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IF 2.578
Hui Yuan,Xuejun Yu,Bowei Shen,Farong Zhang,Wenxiu Jiang,Zhiquan Pan,Hong Zhou
This work describes the preparation of a novel solid acid, poly (styrene-co-allyl sulfonic acid) (St-SAA), and its activity test for extracting diosgenin from Dioscorea Zingiberensis C.H. Wright (DZW). The solid acid was synthesized by the radical polymerization of styrene and sodium allyl sulfonate in water/ethanol solution, followed by the acidification. The prepared solid acid was characterized by infrared spectrum (FTIR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), element analysis, and scanning electron microscope. The solid acid catalyst was used to extract diosgenin from DZW. It was found that the alcoholysis activity of the solid acid was higher than the hydrolysis activity of sulfuric acid with the same mass under the same conditions. Besides, the solid acid can be separated from the reaction mixture for the recycling extraction of diosgenin, and the solid acid has no loss of mass and no decrease of alcoholysis activity after repeated cycles.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 8
·1765-1775
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IF 2.578
Caixia Li,Chao Ma,Juan Li
Because of good thermal stability, nonflammability and rich structural designability, ionic liquids (ILs) have been used as flame retardants for poly(lactic acid) (PLA). However, as a small molecule, IL has the disadvantages of poor thermal stability and water resistance, and so on. In this paper, an imidazole-type poly(ionic liquid) (PIL) containing a phosphate anion was synthesized using 1-vinylimidazole, triethyl phosphate, and 1,2-divinylbenzene and marked as PDVE[DEP]. The PDVE[DEP] was used to improve the flame retardancy of PLA. The flame retardancy and thermal degradation behaviors of PLA/PDVE[DEP] composites were investigated by the limited oxygen index (LOI), UL-94 vertical burning, cone calorimetry, and thermal gravity analysis, and so on. The results showed that only 1.0 wt% PDVE[DEP] allows PLA to achieve the UL-94 V0 rating and obtain LOI value 25.6 vol%. The PDVE[DEP] improve the flame retardancy of PLA by melting-away mode. In addition, it catalyzes the transesterification of PLA and changes the degradation products.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 7
·1591-1601
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IF 2.578
Yongxia Yang,Jing Li,Yong Dong,Jide Wang,Liqin Cao
Monolithic porous copolymers with 3D structure were prepared via CO 2 -in-water high internal phase emulsions template by graft copolymerization of sodium methacrylate (MAANa) on to methyl cellulose (MC) backbone. The yielded copolymer monoliths are characterized by Fourier transform infrared spectra, scanning electron microscopy (SEM), and mechanical instrument, the swelling degree of MC- g -PMAANa monoliths with different crosslinker in diverse pH were investigated. The adsorption performance of monolith to Cu(II) were conducted to explore its adsorption capacity to heavy metal ions from the wastewater. Then, a strategy of in situ growth of metal-organic frameworks (MOFs) on MC- g -PMAANa that adsorbed with metal ions was proposed first. The X-ray powder diffraction, SEM, and Brunauer-Emmett-Teller (BET) surface area result of MC- g -PMAANa/MOFs composites indicated that the MOFs nanoparticles were grown uniformly on the monolith wall without destroying its original 3D porous structure. Compared with MOFs nanoparticle, MC- g -PMAANa/MOFs composites have advantages of easy operation and handle, which more conform to practical application. Furthermore, the antibacterial activity of MC- g -PMAANa/MOFs was evaluated by disk agar diffusion and optical density methods. In addition, MC- g -PMAANa/Cu-BTC composite was applied to dye adsorption, which has proved the underlying application of such composites in dye removal.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 8
·1744-1751
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IF 2.578
Zhongyang Wang,Ali Hasnain,Xujun Sun,Ying Han,Dongshun Liu,Xiaohua Tan,Xiang-Kui Ren,Yakai Feng
In recent years, fluorescent carbon dots (CDs) have been developed and showed potential applications in biomedical imaging and light-emitting diodes (LEDs) for their excellent fluorescent properties. However, it still remains a challenge to incorporate fluorescent CDs into the host matrix in situ to overcome their serious self-quenching. Herein, a one-pot hydrothermal method is used to prepare nano-zirconia with CDs (CDs@ZrO 2 ) nanoparticles. During the reaction, CDs and nano-zirconia are generated simultaneously and connected with silane coupling agent. The CDs@ZrO 2 nanoparticles exhibit tunable emission wavelength from 450 to 535 nm emission by regulating the content of citric acid in the feed. The quantum yield of the CDs@ZrO 2 is up to 23.8%. Furthermore, the CDs@ZrO 2 nanoparticles with regulable fluorescence emission can be used for the fluorescent material to prepare white LEDs. The prepared LED has significant white light emission with color coordinates of (0.30, 0.37) and its color rendering index (CRI) is 67.1. In summary, we have developed the solid-state CDs@ZrO 2 nanoparticles with tunable emission by a valuable strategy, that is, one-pot method, for white LEDs.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 6
·1300-1311
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IF 2.578
Jianyu Qin,Wenchao Zhang,Rongjie Yang
The ease of undesirable agglomeration and a low efficiency are two problems that restrict the application of graphite nanoplatelets (GNPs) in epoxy resins (EP). Herein, a new strategy with melamine (MEL) as the precursor to functionalize GNPs chemically, which form a bonding layer that is compatible with epoxy matrix, is reported. The MEL fragments with secondary amine groups were grafted uniformly on the GNPs surface by covalent junctions to exploit the diazonium chemistry. This behavior led to a better dispersion and a stronger interaction with the epoxy matrix and resulted in an enhanced glass transition temperature and bending strength, compared with the pure EP. When only 1 wt% functionalized GNPs (f-GNPs) was used, the Tg of the modified EP raised of about 15°C compared with pure EP, and the bending strength increased by approximately 39%. The dielectric constant of the EP with f-GNPs was impacted slightly, and the dielectric loss decreased. At 10 5 Hz, the dielectric loss of the EP with 1 wt% f-GNPs decreased by approximately 11% compared with pure EP. Therefore, diazotization modification of the GNPs is a useful approach to improve the compatibility in nanoparticle networks.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 7
·1571-1580
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IF 2.578
Xianlin Xu,Zhufeng Shao,Lei Shi,Bowen Cheng,Xuan Yin,Xupin Zhuang,Youbo Di
Effective proton conducting sites and establishing proton channels are two critical factors in developing high-performance proton exchange membranes. This study first establishes a strategy in designing effective proton conducting channels for Nafion by using solution blowing of sulfonated polyethersulfone (SPES) nanofibers containing CC3, which is an emerging porous organic cage that possesses the advantages of dissolvable organic solvents and high proton conduction from its interconnected three-dimensional pore structure. Our strategy results in SPES nanofiber networks with CC3 uniformly involved in and composite membranes with Nafion-filled interfiber voids. Benefiting from such structural features, the composite membrane exhibits high proton conductivity (0.315 S cm −1 at 80°C and 100% RH), low methanol permeability (0.69 × 10 −7 cm 2 S −1 ), excellent water absorption, thermal and dimensional stability, and single-cell performance. This study provides not only a valuable reference for the application of CC3 but also a new idea for establishment of proton transfer channels.
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高影响因子
POLYMERS FOR ADVANCED TECHNOLOGIES
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2020
·Vol. 31
·期 6
·1426-1436
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IF 2.578
Zhenqian Wei,Jun Wu,Zongru Liu,Yanan Gu,Guifang Luan,Hejing Sun,Qing Yu,Sheng Zhang,Zhongwei Wang
Three commercialized flame retardants, 1,2-bis(diphenylphosphinoyl)ethane (EDPO), 6,6-(1,2-phenethyl)bis-6H-dibenz[c,e][1,2]oxaphosphorin-6,6-dioxide (HTP-6123), and hexa-phenoxy-cyclotriphosphazene (HPCTP), were used to prepare the flame retardant diglycidyl ether of bisphenol A (DGEBA) epoxy resin (EP) under the same experimental conditions. The effects of T g , thermal stability, and water absorption properties of EP caused by the three flame retardants were investigated and compared, together with their flame retardant efficiency. Results showed that the introduction of the three flame retardants improved the flame retardant performance of EP but led to decreases in T g and decomposition temperature. EDPO showed higher flame retardant efficiency than the other two flame retardants. EP/EDPO showed higher thermal stability, better flame retardant performance, higher T g value, and lower water absorption than EP/HTP-6123 and EP/HPCTP. The study discovered that EDPO and HTP-6123 primarily act through the gas phase flame retardant mechanism, while HPCTP is primarily driven by the condensed phase mechanism.
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高影响因子
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