Journal of Macromolecular Science Part A-Pure and Applied Chemistry
·
2021
·
IF 2.168
Yanyang Gao,Wanqiu Liu,Liuyan Tang,Yanan Zhu,Jinqing Qu
As the laws about emission of volatile organic compounds (VOCs) become more and more stringent, low VOC content coatings, such as high solid polyurethane coating, gradually attract great attention. Herein, a series of star-shaped hydroxyl polyesters (SHPs) were synthesized by methyl hexahydrophthalic anhydride (MHHPA), diisopropanolamine (DIPA), and monoglycidyl ether. The number of their average molecular weights is ranged from 913 to 1390 with 1.55–1.75 of PDI. The viscosities of SHPs are low to 1060 mPa·s. The molecular structures of SHPs were characterized by Fourier transform infrared (FTIR) and 1H nuclear magnetic resonance (1H NMR) spectroscopies. The high-solid two-component polyurethane coatings (2 K-PU) from SHP-3 have a 65% of the solid contents and exhibit 20 mPa·s of the applied viscosity with 310 g/L of VOC contents. Moreover, the polyurethane film displays high coating hardness up to 2H, as well as excellent chemical resistance and good thermal stability.
研究领域:
高分子科学
·
材料工程
·
涂料技术
·
环境化学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2012
·Vol. 129
·期 3
·1131-1142
·
IF 1.289
Shitong Ren,Hefei Chang,Lijuan He,Xiaofei Dang,Yanyan Fang,Liaoyun Zhang,Huayi Li,Youliang Hu,Yuan Lin
A series of star block polymers with a hyperbranched core and 26 arms are successfully synthesized by atom transfer radical polymerization of styrene (St), and poly(ethylene glycol) methyl ether methacrylate from a hyperbranched polystyrene (HBPS) multifunctional initiator. All-solid polymer electrolytes composed of these multiarm star polymers and lithium salts are prepared. The influences of polyoxyethylene (PEO) side-chain length, PEO content, lithium salt concentration and type, and the structure of polymer on ionic conductivity are systematically investigated. The resulting polymer electrolyte with the longest PEO side chains exhibits the best ionic conductive properties. The maximum conductivity is 0.8 × 10 −4 S cm −1 at 25°C with EO/Li = 30. All the prepared multiarm star block polymers possess good thermal stability. The mechanical property is greatly improved owing to the existence of polystyrene blocks in the multiarm star polymer molecules, and flexible films can be obtained by solution-casting technique. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
研究领域:
材料科学
·
高分子化学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Jialin Li,Shanshan Zhou,Hao Pang,Yuewen Huang,Bin Wang
Star-shaped superplasticizers exhibited excellent dispersion performance on cement paste , but the molecular structure remained poorly controlled. This study develops three star-shaped block superplasticizers via atom transfer radical polymerization to investigate their effects on fluidity and early hydration in the Portland cement system. The three star-shaped block superplasticizers with acid to ether monomer ratio of 28, 36 and 100, are marked as SPCE-1, SPCE-2 and SPCE-3 respectively. Fluidity test shows that SPCE-1 and SPCE-3 with higher hydrodynamic radius exhibit better initial fluidizing effect than SPCE-2. Besides, there is competitive adsorption of SPCEs between the clinker phase and nano-ettringite in pore solution. SPCE-1 behaves best in fluidity retention due to the increase of adsorption amount over hydration time. A dispersion mechanism based on the extended-DLVO theory was proposed that SPCEs reduce hydrophobic interaction between cement grains and prevent agglomeration between cement grains and air bubbles.
✓ 已验证
产品关联
DOI
高影响因子
Processes
·
2023
·Vol. 11
·期 12
·3429
·
IF 3.5
Fan Shu,Weilin Chen,Gang Liu
Quantum dots (QDs) are emerging as promising candidates for innovative memristive materials, owing to their distinct surface, quantum size, and edge effects. Recent research has focused on tailoring QDs with specific organic molecules to fine-tune charge transfer states between the host and grafted species, as well as enhancing their dispersibility and processability. Violet phosphorus (VP), a newly discovered two-dimensional phosphorus allotrope, offers excellent carrier dynamics, predictable modifiability, and superior oxidation resistance, making it a promising contender in this domain. In this study, we synthesized a rich azobenzene-containing star-shaped polymer diazonium salt (AzoSPD) to functionalize violet phosphorus quantum dots (VPQDs), with the dual objectives of enhancing organic dispersibility and introducing photo-switching capabilities. The synthesized AzoSPD–VPQDs exhibit intramolecular charge transfer characteristics under electrical stimuli of ambient conditions, displaying significant non-volatile rewriteable memory properties and a substantial switching ratio exceeding 2 × 103. Furthermore, the high resistance state (HRS) current can be enhanced by nearly 40 times under 465 nm illumination, enabling optoelectronic information sensing and storage within a single device. This work not only provides insights into enhancing the optoelectronic properties of QDs through functional organic molecular modification but also represents a pioneering exploration of the potential applications of VPQDs in novel memristors.Keywords:violet phosphorus quantum dots;star-shape polymer diazonium salt;memristor;charge transfer mechanism;photoelectric regulation
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD COMPOSITION AND ANALYSIS
·
2021
·
IF 4.556
Wei Jia,Yinghuan Yang,Shuxing Liu,Lin Shi
Irradiation technology has been shown to be a possible preservation technology used to prolong the shelf life and provide microbial decontamination of spices. In this study, the molecular mechanisms of the irradiation-induced accumulation of polyphenols in star anise were explored using metabolomics combined with ultra-high-performance liquid chromatography quadrupole-Orbitrap (UHPLC-Q-Orbitrap) high-resolution mass spectrometry. Fifty-six star anise samples from different areas processed with 2–10 kGy doses of irradiation were compared. The effect of post irradiation storage times ranging from 0 to 70 days was also evaluated. A total of 161 metabolites with variable importance on projection greater than 1 were characterized, and significant differences in flavonoid content in star anise were observed after irradiation. Absolute quantification was used for the quantification of distinctive compounds, and the limit of quantitation of the components was 1.90–6.53 μg/kg. The flavonoid content was stable on the 28th day of storage. The average content of flavonoids increased by 2–9 times due to the breaking of glycoside bonds in star anise by irradiation. C 15 H 11 O 7 + m/z 303.13045 and C 3 H 3 O 2 + m/z 71.01276 were defined as the characteristic fragments of flavonoids according to the mechanism of fragmentation. Checking the extraction ion chromatogram (EIC) characteristic fragments allows straightforward screening of untargeted flavonoids.
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2021
·Vol. 79
·期 6
·4219-4231
·
IF 2.87
Zhang Na,Wu Yansong,Li Yuying,Chen Liduo,Zhang Mingshui,Wang Jun
A novel star iminopyridyl ligand was synthesized in modest yield with 1.0 G star macromolecule and pyridine-2-carboxaldehyde as the raw materials. Reactions of the star iminopyridyl ligand with Fe(II), Co(II) and Ni(II) salts afforded metal complexes (Cat-Fe, Cat-Co and Cat-Ni) in good yields. The compounds were characterized by FT-IR, 1 H NMR, 13 C NMR, UV–Vis, ESI–MS and ICP-MS. In the presence of methylalumoxane (MAO), the iron, cobalt and nickel complexes have demonstrated higher ethylene oligomerization activity (up to 4.28 × 10 5 g/(mol Co h)), affording C 4 as the major product as well as C 6 , C 8 and C 10-18 oligomers. The catalytic activity was quite sensitive to the kind of species. The nature of solvent and co-catalyst significantly affected both the catalytic activity and product distribution. Moreover, the effect of oligomerization parameters (reaction temperature, [Al]/[Co] molar ratio, ethylene pressure) on the catalytic activity and the product distribution was investigated.
✓ 已验证
产品关联
DOI
高影响因子
EUROPEAN POLYMER JOURNAL
·
2020
·
IF 3.862
Pengli Zhang,Yanfang Zhao,Rentong Yu,Jianhe Liao
Six-arm star polycaprolactone with core of cyclotriphosphazene ( s -PCL) was synthesized via ring-opening polymerization and characterized by NMR and GPC . Epoxy thermosets incorporating 10–40 wt % of this copolymer were cured with 4,4′-methylenebis(2-chloroaniline) (MOCA) and 4,4′-diaminodiphenyl sulfone (DDS), respectively. In these thermosets, intermolecular specific interactions had a significant impact on their morphologies. Specifically, no discernable macroscopic phase separation was found in FESEM images of MOCA-cured epoxy resins . However, for the DDS-cured system, s -PCL was partially miscible with the epoxy thermosets, as evidenced with FTIR and DMA. This is may be owning to enriched concentration of hydroxyl groups in the s -PCL favored the miscibility between PCL subchains of carbonyl and the epoxy matrix. Dispersed phase, further confirmed by XRD to be amorphous , with a diameter of 0.34–0.44 μm could be observed ( s -PCL’ content ≤ 20 wt %) in this system. Nevertheless, crystallization of PCL could not be suppressed completely ( s -PCL’ content > 30 wt %). Besides, epoxy thermosets containing crystalline PCL were found to be more resistant to thermal degradation but sensitive to alkaline degradation (10% NaOH aqueous solution) according to TGA and FESEM results. This work presented here is a meaningful report on the presence of alkaline-labile crosslinking points through the whole networks.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2019
·Vol. 136
·期 18
·47458
·
IF 2.188
Xuelian Wei,Huan Hu,Xian Li,Qiang Yin,Li Fan,Yawen Huang,Junxiao Yang
With the development of ultralarge-scale integrated circuits, polymers with low dielectric constant and high thermal stability have aroused great interest. We prepared two novel bridged siloxane-based benzocyclobutene (BCB) star-shaped monomers, tetrakis[dimethyl siloxy-4-(1′,1′-dimethyl-1′-ethyl silicon)-benzocyclobutene] (TDSDES-BCB) and tetrakis(hexamethyl siloxane vinyl-benzocyclobutene) (THSV-BCB), and the corresponding resins were obtained by curing. The structures of TDSDES-BCB and THSV-BCB were confirmed by 1 H-NMR, 13 C-NMR, and 29 Si-NMR spectra and time-of-flight mass spectrometry analysis. The curing behavior of these monomers was investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The dielectric constant of cured TDSDES-BCB is only 2.43 at 10 MHz (that of THSV-BCB is 2.46). In addition, these resins display high thermal stability: the 5 wt % weight loss temperature of cured TDSDES-BCB is about 467 °C (454 °C for THSV-BCB resin). The excellent low dielectric property is attributable to the free volume created by the star-shaped structure and crosslinked network structure of BCB after curing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47458.
✓ 已验证
产品关联
DOI
高影响因子
DRUG DEVELOPMENT AND INDUSTRIAL PHARMACY
·
2019
·
IF 2.367
Jieqiong Lv,Runcheng Liang,Zihua Xia,Yong Li,Zhufen Lv,Dongzhi Hou,Liping Yu,Gang Chen,Yi Liu,Fan Yang
Purpose: A series of β-CD amphiphilic star-shaped copolymers with exceptional characteristics were synthesized and their potential as carriers for micelles drug delivery was investigated.Methods: A series of amphiphilic copolymers based on β-CD were synthesized by introducing poly (acrylic acid)-co-poly(methyl methacrylate)-poly (vinyl pyrrolidone) or poly (acrylic acid)-co-poly(methyl methacrylate)-co-poly(monoacylated-β-CD)-poly (vinyl pyrrolidone) blocks to the primary hydroxyl group positions of β-CD. The micellization behavior of the copolymers, the synthesis conditions, characteristics, drug release in vitro and tissue distribution of vinpocetine (VP) micelles in vivo were investigated.Results: Around 60 types of β-CD amphiphilic star-shaped copolymers were successfully synthesized and the critical micelle concentration ranged from 9.80 × 10−4 to 5.24 × 10−2g/L. The particle size, drug loading and entrapment efficiency of VP-loaded β-CD-P4 micelles prepared with optimal formulation were about 65 nm, 21.44 ± 0.14%, and 49.05 ± 0.36%, respectively. The particles had good sphericity. The cumulative release rates at 72 h of VP-loaded β-CD-P4 micelles in pH 1.0, pH 4.5, pH 6.5, or pH 7.4 media were 93%, 69%, 49%, and 43%, respectively. And, the lung targeting efficiency of VP-loaded β-CD-P4 micelles was 8.98 times higher than that of VP injection.Conclusion: The VP-loaded β-CD-P4 micelles exhibited controlled-release property, pH-induced feature and lung targeting capacity compared with VP injection, suggesting that the β-CD-P4 copolymers are an excellent candidate for micelles drug delivery.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 10
·1716
·
IF 3.164
Feng Guo,Guiying Li,Songmei Ma,Hengquan Zhou,Xinyi Chen
A temperature, glutathione (GSH), and H2O2multi-responsive composite nanocarrier (MSN-SS-Fc@β-CD-PNIPAM) based on β-cyclodextrin-poly(N-isopropylacrylamide) (β-CD-PNIPAM) star polymer capped ferrocene modified mesoporous silica nanoparticles (MSN-SS-Fc) was successfully prepared. The surface of the mesoporous silica was first modified by ferrocene (Fc) via a disulfide bond (–SS–) to form an oxidizing and reducing site and then complexed with a β-CD-PNIPAM star shaped polymer through host–guest interactions as a nano-valve to provide temperature responsive characteristics. The structure and properties of the complex nanoparticles were studied by FTIR, TGA, EDS, Zeta potential, and elemental analysis. Doxorubicin (DOX) and Naproxen (NAP), as model drugs, were loaded into nanocarriers to assess drug loading and release behaviour. The release of drugs from nanocarriers was enhanced with an increase of the GSH, H2O2concentration, or temperatures of the solution. The kinetics of the release process were studied using different models. This nanocarrier presents successful multi-stimuli responsive drug delivery in optimal stimuli and provides potential applications for clinical treatment.Keywords:disulfide bond;ferrocene;multi-responsive;nanocarrier;MSNs
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 28
·15604-15612
·
IF 2.936
Na Xu,Xiaobei Huang,Guangfu Yin,Meijiao Bu,Ximing Pu,Xianchun Chen,Xiaoming Liao,Zhongbing Huang
In contrast with traditional chemotherapy, controlled drug delivery systems provide many advantages. Herein, a thermosensitive star polymer pompon with a core–arm structure was synthesized using a grafting-on method as a thermo-responsive controlled release drug carrier. Single-chain cyclized/knotted poly tetra(ethylene glycol) diacrylate (polyTEGDA) was used as the hydrophobic core, and thermosensitive linear poly(N-isopropylacrylamide-co-N-methylolacrylamide) (poly(NIPAM-co-NMA)) was selected as the hydrophilic arm. Below or above its lower critical solution temperature (LCST), the linear poly(NIPAM-co-NMA) grafted onto the polyTEGDA core adopted a stretched or curled status, respectively, then the drug could be loaded in or extruded out. The LCST of star polyTEGDA-b-poly(NIPAM-co-NMA) was adjusted to slightly above body temperature (37 °C). The antitumor drug doxorubicin (DOX) was successfully loaded into the pompons with a high loading capacity of 19.45%. The cumulative release of DOX from loaded pompons in vitro for 72 hours was 71% and 20.7% at 42 °C and 37 °C, respectively, indicating that the excellent temperature-controlled release characteristics result from the unique thermo-responsive extrusion effect. Moreover, DOX loaded polyTEGDA-b-poly(NIPAM-co-NMA) pompons achieved better antitumor ability against ovarian carcinoma SKOV3 cells at 42 °C compared with that at 37 °C. These results suggest that star polyTEGDA-b-poly(NIPAM-co-NMA) pompons have considerable promise as thermo-responsive controlled drug delivery carriers.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2016
·Vol. 35
·期 1
·54-65
·
IF 1.811
Chen Qi-jing,An Ze-sheng
A series of well-defined core cross-linked star (CCS) polymeric ionic liquids (PILs) were synthesized via a three-step approach. First, the styrenic imidazole-based CCS polymer (S-PVBnIm) was prepared by the RAFT-mediated heterogeneous polymerization in a water/ethanol solution, followed by the quaternization of S-PVBnIm with bromoalkanes and anion exchange. The CCS polymers were characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The obtained CCS polymers were used as the effective emulsifiers for oil-in-water high internal phase emulsions (HIPEs). Multiple oils with different polarity including n -dodecane, undecanol, toluene and octanol were emulsified using 0.5 wt% S-PVBnIm aqueous solution under the acidic condition to form HIPEs with long-term stabilities. The excellent emulsification properties of CCS PILs were demonstrated by HIPE formation for a variety of oils. The properties of HIPEs in terms of emulsion type and oil droplet size were characterized by the confocal laser scanning microscopy (CLSM). The intriguing capability of CCS PILs to stabilize HIPEs of various oils holds great potentials for the practical applications.
✓ 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）