INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Dequan Han,Huhu Tian,Lantao Liu,Luya Cao,Hongzhang Cao,Xiaoli Yu
The prevalent use of disposable plastic tableware presents notable environmental and health risks. An alternative, polylactic acid (PLA), often does not meet usage requirements due to its low crystallization rate. This research introduces an amide-based nucleating agent, BRE-T-100, developed through a straightforward method to enhance the heat resistance and crystallization rate of PLA. This study systematically investigates the impact of BRE-T-100 and other nucleating agents on the properties of PLA composites. The incorporation of 0.8 % BRE-T-100 increases the crystallization temperature of PLA from 109.6 °C to 131.9 °C. Further, the total crystallization time of PLA composites at 120 °C is reduced to <60 s, while maintaining good transparency. BRE-T-100 exhibits superior comprehensive properties compared to talcum, TMC-200, and TMC-300 and is nearly on par with LAK-301. Its application as a nucleating agent in PLA-based disposable tableware shows promise.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL AND EXPERIMENTAL BOTANY
·
2012
·
IF 2.985
Ai-Hua Dai,Yong-Xin Nie,Bin Yu,Qian Li,Ling-Yun Lu,Ji-Gang Bai
To investigate the physiological mechanism of heat stress mitigated by exogenous cinnamic acid (CA), seedlings of a cucumber cultivar ( Cucumis sativus cv. Jinchun no. 4) were pretreated with CA for 2 d and then were exposed to normal (25/18 °C) and elevated (42/38 °C) temperatures for 3 d. 50 μM CA was chosen since it improved growth more than other CA concentrations under heat stress. At 2 d, supply of 50 μM CA elevated the activities of antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), guaiacol peroxidase (GPX, EC 1.11.1.7), glutathione peroxidase (GSH-Px, EC 1.11.1.9), ascorbate peroxidase (APX, EC 1.11.1.11), monodehydroascorbate reductase (MDHAR, EC 1.6.5.4), dehydroascorbate reductase (DHAR, EC 1.8.5.1) and glutathione reductase (GR, EC 1.6.4.2) in cucumber leaves, and it also increased the contents of reduced glutathione (GSH) and ascorbate (AsA). When the CA-pretreated cucumber seedlings have been exposed to heat stress, their antioxidant activities were changed further and were higher than heat treatment alone. Compared to heat treatment, the combination of CA pretreatment and heat also increased relative water content (RWC) of leaves, enhanced levels of proline and soluble sugars, elevated contents of CA and vanillic acid (VA) in leaves, and decreased levels of malonaldehyde (MDA), superoxide radical (O 2 − ) and hydrogen peroxide (H 2 O 2 ), while it resulted in 8.33% of leaf edges being dried up. Meantime, heat had adverse effects on plant growth, RWC, CA and VA contents in leaves, and it as well increased the levels of MDA, O 2 − and H 2 O 2 and made the dried leaf edges to be 79.17%. We conclude that pretreatment with 50 μM CA elevates CA and VA contents in leaves, enhances antioxidant activities under heat stress and decreases lipid peroxidation to some extent, accompanying with increasing proline and soluble sugar levels in heat-stressed leaves, thus the pretreatment enhances heat tolerance of cucumber seedlings.
研究领域:
植物生理学
·
园艺学
✓ 已验证
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2021
·
IF 8.528
Ku Ren,Qinqin Xia,Yongzhuang Liu,Wanke Cheng,Ying Zhu,Yang Liu,Haipeng Yu
Wood is a common-sense thermostable construction material, but the decrease in its structural stability and mechanical strength due to the degradation of lignin and hemicelluloses limits its practical applications in extreme environments. Here, we synthesize a high-performance wood/polyimide composite via the partial substitution of lignin and hemicellulose with super thermostable polyimide . This method involves the rapid partial removal of lignin and hemicellulose in only 3 min using microwave-assisted deep eutectic solvent (DES) pretreatment and subsequent impregnation of polyimide into the pretreated wood. The microwave-assisted DES pretreatment greatly reduced the processing time for lignin and hemicellulose extraction, while preserving the natural cellular scaffold of wood and opening more channels for polyimide infiltration . The obtained wood/polyimide composite showed a 17% improved Young's modulus and a 63% higher dynamic storage modulus than natural wood. The temperature of the first maximum decomposition rate of the wood/polyimide composite significantly increased to 290 °C due to the infiltration of the thermostable polyimide. Furthermore, the wood/polyimide composite exhibited a smoke suppression property (33% decrease), and the time to produce smoke was delayed by 200 s. Our work provides a rapid pretreatment method for wood and a substitution compositing method to produce wood-framed polyimide composites with excellent thermostability.
研究领域:
材料科学
·
林业工程
✓ 已验证
DOI
高影响因子
ADVANCED ENGINEERING MATERIALS
·
2021
·Vol. 24
·期 3
·2100940
·
IF 3.862
Liubo Liang,Botao Jiang,Tonghua Wu,Youmei Ma,Shuling Zhang,Guibin Wang
Glass fiber/poly(ether ether ketone) (GF/PEEK) composite foams with improved compressive strength and heat resistance can be successfully prepared using a simple and environmentally friendly supercritical carbon dioxide (sc-CO 2 ) foaming technology. The cell morphologies of the foams can be controlled by adjusting the GF content and foaming parameters, including the saturation temperature, saturation time, saturation pressure, and depressurization rate. With a foam density of 0.55 g cm −3 , the PEEK-based composite foam having 30% GF content has a 10% compressive strength of 11.07 MPa, and its density varies negligibly up to 330.0 °C. The GF/PEEK composite foams having high GF contents show significantly better properties than those having low GF contents as a result of the supporting and strengthening effect of the GF in the PEEK cell walls. The GF/PEEK composite foams also show good corrosion resistance. As a result of these properties, the GF/PEEK composite foams are promising high-performance materials for use in extreme environments.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2021
·Vol. 139
·期 17
·52041
·
IF 3.125
Zhiyuan Song,Jie Wang,Qian Tao,Yang Yu,Hui Zhang,Chuanqun Hu,Hongyu Cen,Xuan Zheng,Tao Hu,Chonggang Wu
Zn-salt poly(styrene– ran –cinnamic acid) (SCA–Zn) ionomers were successfully synthesized via the melt neutralization of poly(styrene– ran –cinnamic acid) (SCA), which has a comparable molecular weight ( = 217,000) to commercial polystyrene (PS), with different mass fractions of ZnO (0.62, 1.6, and 3.9 wt.%) and the successful synthesis was confirmed by Fourier transform infrared spectroscopy. The mechanical properties, heat resistance, and processibility of the PS, SCA, and SCA–Zn samples were characterized. Compared to SCA, the three SCA–Zn ionomers exhibited significantly higher α cN values, with the ionomers containing 1.6 and 3.9 wt.% ZnO were 11.4% and 68.6% higher than that of SCA, respectively. Compared to commercial PS, SCA–Zn also exhibited significant improvements in heat resistance (glass transition temperature and vicat softening temperature both improved by about 20 °C) and impact toughness ( α cN values of the ionomers containing 1.6 and 3.9 wt.% ZnO were 69.6% and 156.5% higher than that of PS), while the processability of SCA–Zn was not significantly worse than that of PS. This method efficiently improves both the toughness and heat resistance of PS, providing an efficient way to expand the market application of styrenic resins.
研究领域:
高分子材料
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2017
·Vol. 9
·期 7
·296
·
IF 3.364
Caili Dai,Zhongliang Xu,Yining Wu,Chenwei Zou,Xuepeng Wu,Tao Wang,Xu Guo,Mingwei Zhao
Water-soluble polymers are widely used in oilfields. The rheological behaviors of these polymers in high-salinity solution are very important for stimulation of high-salinity reservoirs. In this work, a novel thermal-resistant and shear-stable amphoteric polyacrylamide (PASD), prepared from acrylamide (AM), sodium styrene sulfonate (SSS), and acryloxyethyl trimethylammonium chloride (DAC) monomers, was prepared by free-radical polymerization in high-salinity solution. The amphoteric polyacrylamide was characterized by Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance spectroscopy (1H NMR), elemental analysis, thermogravimetric analysis (TG), and scanning electron microscopy (SEM). The amphoteric polyacrylamide exhibited excellent salinity tolerance. The slow increase in apparent viscosity of the polymer with increase in salinity was interesting. The amphoteric polyacrylamide showed perfect temperature resistance in high-salinity solution. The viscosity retention reached 38.9% at 120 °C and was restored to 87.8% of its initial viscosity when temperature was decreased to room temperature. The retention ratio of apparent viscosity reached 49.7% at 170 s−1and could still retain it at 25.8% at 1000 s−1. All these results demonstrated that PASD had excellent thermal-resistance and shear-stability in high-salinity solution. We expect that this work could provide a new strategy to design polymers with excellent salinity-tolerance, thermal-resistance, and shear-stability performances.Keywords:amphoteric polyacrylamide;high-salinity solution;thermal-resistance;shear-stability
研究领域:
化学工程
·
石油工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2024
·
IF 15.8
He Ji,Shouhua Feng,Ming Yang
Polymer fibers that combine high toughness and heat resistance are hard to achieve, which, however, hold tremendous promise in demanding applications such as aerospace and military. This prohibitive design task exists due to the opposing property dependencies on chain dynamics because traditional heat-resistant materials with rigid molecular structures typically lack the mechanism of energy dissipation. Aramid nanofibers have received great attention as high-performance nanoscale building units due to their intriguing mechanical and thermal properties, but their distinct structural features are yet to be fully captured. We show that aramid nanofibers form nanoscale crimps during the removal of water, which primarily resides at the defect planes of pleated sheets, where the folding can occur. The precise control of such a structural relaxation can be realized by exerting axial loadings on hydrogel fibers, which allows the emergence of aramid fibers with varying angles of crimps. These crimped fibers integrate high toughness with heat resistance, thanks to the extensible nature of nanoscale crimps with rigid molecular structures of poly(p-phenylene terephthalamide), promising as a template for stable stretchable electronics. The tensile strength/modulus (392–944 MPa/11–29 GPa), stretchability (25–163%), and toughness (154–445 MJ/cm3) are achieved according to the degree of crimping. Intriguingly, a toughness of around 430 MJ/m3 can be maintained after calcination below the relaxation temperature (259 °C) for 50 h. Even after calcination at 300 °C for 10 h, a toughness of 310 MJ/m3 is kept, outperforming existing polymer materials. Our multiscale design strategy based on water-bearing aramid nanofibers provides a potent pathway for tackling the challenge for achieving conflicting property combinations.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2018
·Vol. 136
·期 14
·47310
·
IF 1.901
Xiaoyong Zhang,Jinmei He,Lipei Yue,Yongping Bai,Huihui Liu
The development of adhesive tapes that can be applied at high temperature is a major challenge for pressure-sensitive adhesives (PSAs). To date, the heat resistance of PSAs has not been investigated in sufficient details. In this study, based on the relationship between curing structures and properties, a series of acrylic PSAs with excellent heat resistance were prepared. Commercial zirconium acetylacetonate (ZrACA), desmodur L75 (L75), and N , N , N ′, N ′-tetrakis(2,3-epoxypropyl)- m -xylene-α,α′-diamine (GA240) were employed as heat-curing agents. Trimethylolpropane triacrylate (TMPTA) was used as ultraviolet (UV)-curing agent to form semi-interpenetration polymer network structures after UV exposure. The influences of different curing agents on the thermal stability, adhesion performance, gel fraction, and viscoelastic of PSAs were explored. The results showed that the PSAs cured by L75, GA240, and TMPTA exhibited excellent heat resistance. Especially, when the content of L75 was 1.0 wt %, the PSAs could be peeled off substrate without residues on substrate surface after treatment at 170 °C for 4 h, while the nonmodified acrylic PSAs possessed residues after treatment from 110 °C. The cured PSAs adhesive performance was evaluated showing maximum 180° peel strength of 16.7 N/25 mm comparable to current PSAs. These resulting PSAs showed high heat resistance and they are suitable for a broad range of special fields. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47310.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2022
·Vol. 15
·期 1
·141
·
IF 4.967
Jinman Zhou,Xianyuan Liu,Xiaojiang He,Haoxin Wang,Dongli Ma,Xianyong Lu
Flame-retardant, thermal insulation, mechanically robust, and comprehensive protection against extreme environmental threats aerogels are highly desirable for protective equipment. Herein, inspired by the core (organic)-shell (inorganic) structure of lobster antenna, fire-retardant and mechanically robust aramid fibers@silica nanocomposite aerogels with core-shell structures are fabricated via the sol-gel-film transformation and chemical vapor deposition process. The thickness of silica coating can be well-defined and controlled by the CVD time. Aramid fibers@silica nanocomposite aerogels show high heat resistance (530 °C), low thermal conductivity of 0.030 W·m−1·K−1, high tensile strength of 7.5 MPa and good flexibility. More importantly, aramid fibers@silica aerogels have high flame retardancy with limiting oxygen index 36.5. In addition, this material fabricated by the simple preparation process is believed to have potential application value in the field of aerospace or high-temperature thermal protection.Keywords:aramid nanofibers;bionic structure;silica;heat resistance;flame retardancy
研究领域:
材料科学
·
仿生学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Gang Wu,Congjin Hu,Junyi Cui,Si-Chong Chen,Yu-Zhong Wang
Despite considerable success in design and preparation of superhydrophobic particles, a facile and low-cost approach to develop multifunctional particles, especially microcapsules with the integrated performances of intrinsically long-lasting and highly stable superhydrophobicity and other passive/active functionalities, remains extremely challenging and is still in its infancy. Herein, we report a microcapsule (MC) with a micro/nano-hierarchical shell and a phase change material (PCM) core by a low-cost one-pot method. The resulting microcapsules (MCs) possess concurrent features of superhydrophobicity and thermal energy storage. Against thermal attack up to approximately 240 °C, the microstructure of MCs is nearly intact to avoid an obvious leakage of encapsulated PCM at high temperature, and meanwhile superhydrophobicity of MCs is enhanced unexpectedly to a static contact angle (CA) of 167.4 ± 0.3° and slide angle (SA) of 5 ± 0.5°. After conventional storage of 80 days, MCs still show a good superhydrophobicity with a nearly constant CA and slightly increasing SA. In addition, encapsulated PCM has high enthalpy up to 176 J/g, nearly unchanged Tm, Tom, and Tos, and negligible change (less than 0.1%) of normalized melting and solidified enthalpies over 100 melting/solidification cycles, indicating high latent heat, low effect of shell on thermal diffusion, and excellent durability during phase transition cycling, respectively. An isothermal stage at around 28 and 26 °C being close to human comfort temperature appears separately in heating-up and cooling-down processes of the epoxy matrix with embedded MCs, revealing a good temperature-regulated property of MCs. Accordingly, the MCs as a promising candidate with all-in-one features of superhydrophobicity, temperature-regulated properties, thermal-resistance, and durability would stimulate wide applications in self-cleaning/energy-saving smart buildings and facilities.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2021
·
IF 9.078
Ting Gu,De-xiang Sun,Xiao-dong Qi,Jing-hui Yang,Cheng-shou Zhao,Yan-zhou Lei,Yong Wang
The wide application of the biodegradable polymers is the developing direction of the next generation microelectronic devices and electronic packaging because it can greatly reduce the risk of plastic pollution. However, most of biodegradable polymers have low thermal conductivity and low heat resistance. Synchronously improving the thermal conductivity and heat resistance of the biodegradable polymers without sacrificing the other performances is still great challenging. In this work, a novel method was proposed to highly efficiently improve the thermal properties of the poly( l -lactic acid) (PLLA) composites. To achieve this goal, hydroxylated graphene nanoplatelets were obtained by wet ball milling technology, and then ring-opening polymerization of lactide was initiated, and poly( d -lactic acid) (PDLA) and PLLA molecular chains were grafted on the hydroxylated graphene nanoplatelets to obtain the PDLA-graft-graphene nanoplatelets (G-g-PDLA) and PLLA-graft-graphene nanoplatelets (G-g-PLLA), respectively. Finally, the PLLA/G-g-PDLA and PLLA/G-g-PLLA composites were fabricated through melt compounding processing. The results showed that the PDLA molecular chains on the graphene nanoplatelets promoted the formation of the stereocomplex crystallites at the interface. Compared with the pure PLLA and PLLA/G-g-PLLA composites, the PLLA/G-g-PDLA composites exhibited higher thermal conductivity, largely enhanced heat distortion temperature, and better mechanical properties at high environmental temperature. For example, at G-g-PDLA content of 5 wt %, the composite sample showed the thermal conductivity of 1.12 W m −1 K −1 and heat distortion temperature of 200 °C, which were 387 % and 65 °C higher than those of the pure PLLA, respectively. Morphological and microstructural characterizations were carried out and the mechanisms based on SCs formation at the interface were proposed. This work lights up the route for the application of the PLLA in the next generation microelectronic devices.
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
POLYMER DEGRADATION AND STABILITY
·
2021
·
IF 5.03
Zilong Zhang,Xiaohan Li,Ying Bao,Wei Wei,Xiaojie Li,Xiaoya Liu
Development of new allyl compounds to modify bismaleimide (BMI) resins for improving the toughness while maintaining a high thermal performance and flame retardancy is still urgent. In this study, we synthesized the allyl ether of resveratrol (AER), a bio-based allyl compound, to modify BMI resin. A series of BMI/AER resins (BA resins) were prepared by changing the molar ratio of BMI to AER. Compared with 2,2′-diallyl bisphenol A (DBA) modified BMI resins (BD resins), which has been widely used in industry, BA resins can be cured at a lower temperature. Although the toughness of cured BA resins was slightly inferior than that of cured BD resins, the cured BA resins exhibited much superior thermal performance and flame retardancy to the cured BD resins. For the BA-0.8 resin with a molar ratio of imide to allyl groups of 1:0.8, the glass transition temperature, thermal decomposition temperature of 5% weight loss, and char yield of the cured product were as high as 388 °C, 415 °C, and 48.6%, respectively. Meanwhile, the UL-94 and limit oxygen index (LOI) tests revealed an excellent flame retardancy of the cured BA-0.8 resin with V-0 level and LOI of 37.7%. The remarkable properties were attributed to AER with the tri-functionality and stiffness conjugated stilbene backbone giving the cured resins higher crosslinking density, chain rigidity and thermostability compared with DBA. This work provides a novel insight into the development of high-performance bismaleimide-based thermosetting resins with excellent halogen-free and phosphorus-free intrinsic flame retardancy.
研究领域:
材料科学
·
化学工程
✓ 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）