Shi-Ai Xu

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Name: 徐世爱; Xu, ShiAi

Organization: East China University of Science and Technology , China

Department: School of Materials Science and Engineering

Title: Professor(PhD)

TOPICS

Polymer

Polyimide Polybenzimidazoles

Chemicals
References

Effect of inorganic–organic surface modification of calcium sulfate whiskers on mechanical and thermal properties of calcium sulfate whisker/poly(vinyl chloride) composites

Co-reporter:Yunhua Lu;Nan Jiang;Xingwei Li;Shiai Xu

RSC Advances (2011-Present) 2017 vol. 7(Issue 73) pp:46486-46498

Publication Date(Web):2017/09/26

DOI:10.1039/C7RA09193A

Coupling agents are traditionally used to improve the interfacial adhesion between inorganic fillers and a polymer matrix; however, the application of this method is somewhat limited by the number of hydroxyl groups on the surface of inorganic fillers. In this study, a layer of calcium hydroxide (Ca(OH)2) was coated on the surfaces of calcium sulfate whiskers (CSW) through hydroxylation modification using sodium hydroxide (NaOH) to increase the hydroxyl groups of the CSW, and then a polyether titanate coupling agent synthesized in our lab was used to modify Ca(OH)2 coated CSW in order to improve their compatibility with poly(vinyl chloride) (PVC). The chemical structure and surface properties of the modified CSW were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA). Then, CSW/PVC and modified CSW/PVC composites were prepared via a two-roll mill, and the effects of the inorganic–organic surface modification of CSW on their mechanical and thermal properties were evaluated. The results show that hydroxylation modification can further improve the compatibility and the interfacial adhesion between CSW and the PVC matrix, which results in better mechanical and thermal properties.

Titanium conversion coatings on the aluminum foil AA 8021 used for lithium–ion battery package

Co-reporter:Xu-Feng Xia, Ying-Ying Gu, Shi-Ai Xu

Applied Surface Science 2017 Volume 419(Volume 419) pp:

Publication Date(Web):15 October 2017

DOI:10.1016/j.apsusc.2017.03.040

•An environment-friendly Ti conversion coating was prepared on the Al foil.•The wettability of Ti conversion coating was investigated by contact angle test.•Ti treatment can significantly improve the corrosion resistance and peeling strength of Al/P composites.In this study, an environment-friendly titanium (Ti) conversion coating was successfully deposited on the aluminum foil AA 8021 in the solution containing hexafluorotitanic acid (H2TiF6), and its morphology, composition, growth process, hydrophilicity and corrosion resistance were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), X-ray photoelectric spectroscopy (XPS), contact-angle measurements (CAM) and salt spray exposure. The peeling strength between the Ti treated Al foil and the modified polypropylene (PP) film (PP grafted with maleic anhydride, PP-g-MAH) (Al/PP-g-MAH) was measured by T-peeling test. The results show that the Ti conversion coating is a multi-component coating composed primarily of metal oxides (TiO2 and Al2O3) and metal fluoride (AlF3). Ti treated Al foil shows better corrosion resistance than untreated and alkali-cleaned Al foils. The peeling strength of PP-g-MAH film with Ti treated Al foils is approximately 30 times higher than that with untreated Al foils. Thus, Ti treatment is a promising approach to improve the corrosion resistance and peeling strength of aluminum/polymer composite film (Al/P) used in the lithium–ion battery package.Download high-res image (87KB)Download full-size image

Synthesis of new polyether titanate coupling agents with different polyethyleneglycol segment lengths and their compatibilization in calcium sulfate whisker/poly(vinyl chloride) composites

Co-reporter:Yunhua Lu;Weipeng Zhang;Xingwei Li;Shiai Xu

RSC Advances (2011-Present) 2017 vol. 7(Issue 50) pp:31628-31640

Publication Date(Web):2017/06/16

DOI:10.1039/C7RA03692B

Six new polyether titanate coupling agents with different polyethyleneglycol (PEG) segment lengths were prepared in this study and were then used to modify calcium sulfate whiskers (CSWs) in order to improve the compatibility between CSWs and poly(vinyl chloride) (PVC). The chemical structure of these coupling agents was characterized by FTIR, Raman, 1H NMR and 31P NMR, and the surface properties of CSWs modified by the coupling agents (mCSWs) were characterized by FTIR, SEM-EDS and XPS. Then, CSW/PVC and mCSW/PVC composites were prepared using a two-roll mill, and their mechanical and thermal properties were characterized to investigate the effects of the PEG segment length of the coupling agents on the performance and compatibility of the composites. The results show that the new coupling agents can significantly improve the compatibility and the interfacial adhesion between CSWs and the PVC matrix, which results in a significant improvement of the comprehensive performance of mCSW/PVC composites. PEG4000 shows the best modification effect on CSWs. Finally, the underlying mechanisms are discussed.

Curing kinetics of epoxy cured by cardanol-based phenalkamines synthesized from different polyethylenepolyamines by Mannich reaction

Co-reporter:Junhui Zhang;Shiai Xu

Iranian Polymer Journal 2017 Volume 26( Issue 7) pp:499-509

Publication Date(Web):06 June 2017

DOI:10.1007/s13726-017-0538-9

Phenalkamines with different structures are expected to affect the curing reaction of epoxy, yet the exact mechanism remains to be elucidated. In this study, four cardanol-based phenalkamines (named PK1, PK2, PK3, and PK4, respectively), synthesized from ethylenediamine, diethylenetriamine, triethylenetetramine, and pentaethylenehexamine, were used as curing agents in diglycidyl ether of bisphenol A (DGEBA) epoxy system. The phenalkamines were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, and time-of-flight secondary ion mass spectrometry. The curing behaviors and kinetics were investigated by non-isothermal differential scanning calorimetry, and the activation energies of the reactions (Eα) were determined using Kissinger–Akahira–Sunose (KAS) and Starink methods. The results indicate a similar curing mechanism for all four phenalkamines. All Eα values remain almost constant in the range of 0.05 ≤ α ≤ 0.6, and increase dramatically after α > 0.6 due to greater viscosity of the reaction systems. The diffusion of reactive groups plays an increasingly important role in determining the curing kinetics. In addition, DGEBA/PK1 and DGEBA/PK2 have lower initial Eα values than DGEBA/PK3 and DGEBA/PK4, because PK1 and PK2 have lower viscosity than PK3 and PK4. When α is high, DGEBA/PK1 and DGEBA/PK2 have higher Eα values than DGEBA/PK3 and DGEBA/PK4, because more tertiary amine groups can be formed in the reactions between the epoxy and secondary amine groups in the DGEBA/PK3 and DGEBA/PK4 systems, which catalyze the curing reaction and it thus lowers energetic barrier.

Phosphoric acid-doped organic-inorganic cross-linked sulfonated poly(imide-benzimidazole) for high temperature proton exchange membrane fuel cells

Co-reporter:Zhouying Yue, Yang-Ben Cai, Shiai Xu

International Journal of Hydrogen Energy 2016 Volume 41(Issue 24) pp:10421-10429

Publication Date(Web):29 June 2016

DOI:10.1016/j.ijhydene.2015.10.057

•Organic-inorganic cross-linked membranes are synthesized.•KH560 is used as a cross-linker and a PA-absorbing site.•Cross-linked membranes are PA-doped.•The resulted membranes have good mechanical strength and chemical stability.•The resulted membranes have high proton conductivity.Silane-cross-linked sulfonated poly(imide benzimidazole) (CSiSPIBI) membranes were prepared using γ-(2,3-epoxypropoxy) propyltrimethoxysilane (KH560) as a cross-linker, and the cross-linked structure was characterized using Fourier transform infrared spectroscopy and solubility test. The resulted cross-linked membranes were further doped with phosphoric acid (PA) by means of the acid–base interaction with the alkaline imidazole ring and the electrostatic interaction with siloxane. The results show that PA-doped CSiSPIBI membranes have high proton conductivity due to the formation of a new proton transport pathway between PA and sulfonic acid. Under high temperature and low humidity conditions, the proton conductivity of PA-doped sulfonated membranes is one to two orders of magnitude higher than that of non-PA-doped membranes and PA-doped non-sulfonated membranes. The silane-cross-linked membranes display improved chemical stability and mechanical strength, especially the oxidative stability. The complete dissolution time in Fenton's reagent increases from 510 min for the sulfonated polyimide/polybenzimidazole blend membrane to 1450 min for the silane-cross-linked membrane.

Facile synthesis of mesoporous melamine-formaldehyde spheres for carbon dioxide capture

Co-reporter:Zhongfei Lv, Dandan Zhao and Shiai Xu

RSC Advances 2016 vol. 6(Issue 64) pp:59619-59623

Publication Date(Web):15 Jun 2016

DOI:10.1039/C6RA09508A

Greenhouse effect and excessive carbon dioxide (CO2) emissions have caused widespread public concern in recent years. Tremendous efforts have been made towards CO2 capture promoting the development of numerous sorbents. In this study, mesoporous melamine-formaldehyde spheres (MMFSs) with high surface area (298 m2 g−1), uniform pore sizes (3.0 nm) and high nitrogen content (∼45%) have been successfully synthesized using Pluronic F127 and sodium dodecyl sulfonate (SDS) as the templates, glycol as the organic co-solvent, and melamine (M) and paraformaldehyde (PFA) as the precursors, respectively. These MMFSs are highly effective in capturing CO2, with the maximum adsorption capacity of 48.0 mg g−1 at 273 K for CO2. Moreover, the CO2/N2 selectivity at 298 K reaches 24.3, which is attributed to the high N content allowing for high binding affinity with CO2 and the well-defined mesopores (3.0 nm). This approach suggests a new direction in designing CO2 sorbents with excellent selectivity.

Preparation of a Crosslinked Chitosan Coated Calcium Sulfate Whisker and Its Reinforcement in Polyvinyl Chloride

Co-reporter:Jiayang Cui, Yangben Cai, Wenjin Yuan, Zhongfei Lv, Shiai Xu

Journal of Materials Science & Technology 2016 Volume 32(Issue 8) pp:745-752

Publication Date(Web):August 2016

DOI:10.1016/j.jmst.2016.06.006

A calcium sulfate whisker (CSW) coated with glutaraldehyde crosslinked chitosan (GACS) was prepared to reinforce polyvinyl chloride (PVC) in this study. The results show that the optimum concentration of both chitosan (CS) and glutaraldehyde (GA) is 0.05 wt%. The tensile strength, impact strength, flexural modulus and vicat softening temperature of the PVC composite with 12 wt% of modified CSW are increased by 17.5%, 40.4%, 0.8% and 3.8% compared with those of the PVC composite with 12 wt% of unmodified CSW, and by 2.9%, 42.4%, 27.1% and 6.8% compared with those of pure PVC, respectively. The dynamic mechanical analysis results indicate that the modified CSW/PVC composite exhibits much higher storage modulus and glass transition temperature than those of unmodified CSW/PVC composite and pure PVC. In addition, the modified CSW/PVC composite also demonstrates good thermal properties with a high rapidest decomposition temperature (Trpd) and char residue. The scanning electron microscopy images of tensile-fractured surfaces show that the modified CSW has a strong interfacial adhesion with PVC matrix.

Proton conducting sulfonated poly (imide-benzimidazole) with tunable density of covalent/ionic cross-linking for fuel cell membranes

Co-reporter:Zhouying Yue, Yang-Ben Cai, Shiai Xu

Journal of Power Sources 2015 Volume 286() pp:571-579

Publication Date(Web):15 July 2015

DOI:10.1016/j.jpowsour.2015.04.030

•SPIBI with more cross-linking sites in repeating unit are synthesized.•CBr-ySPIBI-x membranes are prepared by SPIBI and a new cross-linker.•Covalent cross-linked membranes show enough cross-linking degree under high sulfonation level.•Membranes have good chemical and oxidative stability, and mechanical properties.Ionic cross-linked sulfonated polyimides containing bis-benzimidazole rings have been prepared from 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTDA), 6,6′-bis[2-(4-aminophenyl)benzimidazole] (BAPBI) and 3,3′-bis(4-sulfophenoxy)- benzidine (BSPOB). A new cross-linker, 4,4′-bibromomethenyl diphenyl ether, is used to induce covalent cross-linking between halogen and imidazole groups in SPIBI chains via a facile thermally activated reaction. The resulted covalent and ionic cross-linked membranes show an improved resistance to hydrolytic attack in deionized water at 80 °C (more than two months) and free radical attack in Fenton's solution (more than 690 min) as compared to non-cross-linked SPIBIs (less than two days and 270 min, respectively). Cross-linking also results in a reduction in proton conductivity due to the blockage of a hydrophilic channel. However, all the prepared CBr-ySPIBI-x membranes show a proton conductivity higher than 10−2 S cm−1 under hydrous condition. This could be attributed to the fact that more cross-linking sites are contained in each repeating unit, which ensures enough cross-linking degree at high sulfonation level. All these results suggest that CBr-ySPIBI-x membranes have a great potential for applications in the proton exchange membrane fuel cells.

Magnetically recoverable mesoporous melamine–formaldehyde nanoparticles as an efficient adsorbent for hexavalent chromium removal

Co-reporter:Zhongfei Lv, Dandan Zhao, Changsheng Liang, Jiayang Cui, Yangben Cai and Shiai Xu

RSC Advances 2015 vol. 5(Issue 102) pp:83788-83794

Publication Date(Web):25 Sep 2015

DOI:10.1039/C5RA14439F

Functional porous nanoparticles have been considered as potential adsorbents for chromium (Cr) removal due to their unique properties such as high surface area, nanosized structure and specific affinity for heavy metal ions. Among these adsorbents, magnetic supports are one of the most efficient adsorbents for their unique advantages of easy separation under external magnetic fields. In this study, magnetic mesoporous melamine–formaldehyde (MMMF) nanoparticles with high surface area (393 m2 g−1), uniform pore sizes (6.9 nm), and relatively high saturation magnetization (4.3 emu per g) have been prepared. These MMMF nanoparticles are highly effective in removing toxic hexavalent chromium (Cr(VI)) from water within 5 to 10 min. More importantly, they can be easily regenerated by a simple basic treatment (0.1 M NaOH) and reused at least five times. The effects of initial Cr(VI) concentration, temperature and pH on the adsorption properties of MMMF are also investigated. The superior adsorption properties of MMMF make them an attractive adsorbent for water quality purification and improvement.

A facile route for the synthesis of mesoporous melamine-formaldehyde resins for hexavalent chromium removal

Co-reporter:Zhongfei Lv, Changsheng Liang, Jiayang Cui, Yanan Zhang and Shiai Xu

RSC Advances 2015 vol. 5(Issue 24) pp:18213-18217

Publication Date(Web):03 Feb 2015

DOI:10.1039/C4RA16866F

A highly mesoporous melamine-formaldehyde resin (MMF) has been successfully synthesized through a facile route. It shows a relatively high surface area (317 m2 g−1), uniform pore sizes (8.0 nm), enhanced adsorption capacity (66.65 mg g−1) and selectivity for hexavalent chromium.

Curing kinetics of nanostructured epoxy blends toughened with epoxidized carboxyl-terminated liquid rubber

Co-reporter:Kai Zhao, Juan Wang, Xiaoxue Song, Changsheng Liang, Shiai Xu

Thermochimica Acta 2015 Volume 605() pp:8-15

Publication Date(Web):10 April 2015

DOI:10.1016/j.tca.2015.02.007

•Epoxidized liquid rubber is used to toughen epoxy resin.•Curing kinetics is studied by dynamic DSC method under non-isothermal conditions.•Málek method is used to determine the most suitable kinetic model.The curing kinetics of epoxy resin/rubber blends containing different contents of epoxidized carboxyl-terminated butadiene acrylonitrile (ECTBN) with different epoxidation degrees is studied using non-isothermal differential scanning calorimetry (DSC) at different heating rates. Kissinger method is used to calculate the apparent activation energies, and Málek method is used to determine the most suitable kinetic model characterizing the curing process. The results show that the curing reaction is catalyzed by the hydroxyl and carboxyl groups in ECTBNs, whereas hindered by the viscosity increment owing to addition of rubber. Within the chemical reaction control stage, the curing process could be well described by the two-parameter autocatalytic kinetic model of Šesták–Berggren, and the simulated curves calculated by Šesták–Berggren model show a good agreement with that experimentally determined.

Compatibilization of polypropylene/recycled polyethylene terephthalate blends with maleic anhydride grafted polypropylene in the presence of diallyl phthalate

Co-reporter:Yeling Zhu;Changsheng Liang;Yang Bo;Shiai Xu

Journal of Polymer Research 2015 Volume 22( Issue 3) pp:

Publication Date(Web):2015 March

DOI:10.1007/s10965-014-0591-4

Bi-functional co-agent, diallyl phthalate (DAP), −assisted melting free-radical grafting of maleic anhydride (MAH) on polypropylene (PP) is carried out by reactive extrusion. The PP/recycled polyethylene terephthalate (rPET) blends with and without PP-g-MAH/DAP (PP grafted with both MAH and DAP) are conducted on a twin-screw extruder. It reveals that the introduction of DAP can significantly enhance the grafting degree of MAH and decrease the chain scission of PP. The maximum extent of MAH grafting (1.5 wt.%) is obtained when DCP and MAH contents are 0.5 and 6.0 wt.%, respectively, and the DAP/MAH molar ratio is 0.3. Besides, differential scanning calorimetry (DSC) analysis shows that the crystallization temperature of grafted PP is higher than that of pure PP due to the nucleation of grafted groups. Fourier transform infrared spectroscopy (FTIR) analysis proves that chemical reactions take place between PP-g-MAH/DAP and rPET. In particular, scanning electron microscopy (SEM) observations demonstrate that, the PP/rPET blends compatibilized with PP-g-MAH/DAP show enhanced adhesion at the interface comparing with the binary PP/rPET blend, which is also proved by DSC measurements, dynamic mechanical analysis (DMA) and mechanical properties.

A novel surface modification for calcium sulfate whisker used for reinforcement of poly(vinyl chloride)

Co-reporter:Wenjin Yuan;Jiayang Cui;Yangben Cai;Shiai Xu

Journal of Polymer Research 2015 Volume 22( Issue 9) pp:

Publication Date(Web):2015 September

DOI:10.1007/s10965-015-0813-4

A novel technique is developed in this study to modify the surface of calcium sulfate whisker (CSW) for the preparation of high-performance CSW/poly(vinyl chloride) (PVC) composites. The CSW coated with poly(vinyl alcohol) (PVA) and then cross-linked by glutaraldehyde is used to strengthen PVC, and the surface morphology and mechanical properties of CSW/PVC composites are investigated. It shows that the mechanical properties of the cross-linked PVA modified CSW/PVC (cPVA@CSW/PVC) composites are significantly improved, their yield strength, breaking strength, tensile modulus and elongation at break are 65.7 MPa, 53.5 MPa, 1772 MPa and 225 %, with an increase of 7.2, 13.1, 7.6 and 8.2 % as compared with that of the unmodified CSW/PVC composites, respectively. The improvement in the mechanical properties can be attributed to the strong interfacial adhesion between cPVA@CSW and PVC matrix, because the modified CSW has abundant hydroxyl groups that can produce a strong interaction with PVC. This method is simple and inexpensive, and can be applied in large scale.

Morphology and properties of nanostructured epoxy blends toughened with epoxidized carboxyl-terminated liquid rubber

Co-reporter:Kai Zhao;Xiao-Xue Song;Chang-Sheng Liang;Juan Wang

Iranian Polymer Journal 2015 Volume 24( Issue 5) pp:425-435

Publication Date(Web):2015 May

DOI:10.1007/s13726-015-0334-3

A liquid carboxyl-terminated butadiene acrylonitrile (CTBN) rubber was epoxidized using hydrogen peroxide and formic acid, and the epoxidized CTBN (ECTBN) rubbers with different degrees of epoxidation were used to toughen the epoxy resin. The effects of epoxidation degree on the morphology and mechanical and thermal properties of the ECTBN/epoxy blends were then investigated. It was shown that the CTBN particles dispersed in the matrix in micro-scale, presenting sea–island structure, and the blends were opaque, whereas the ECTBN particles dispersed in nano-scale in the ECTBN/epoxy blends, forming nanostructure, and the blends presented good transparency. The glass transition temperatures of the blends decreased with rubber content or epoxidation degree. The mechanical properties of the ECTBN/epoxy blends and the traditional CTBN/epoxy blends were measured and compared, and better balanced properties were observed for the ECTBN/epoxy blends. After the addition of ECTBN, the impact strength and the tensile strength of the blends increased 2.3 and 1.6 times, respectively, and elongation-at-break was about 4 times that of the neat epoxy resin. In particular, the Young’s modulus improved or at least retained after the addition of ECTBN, being considerably higher than that of the CTBN-modified blends. Based on the morphology observations by SEM and TEM, the toughening mechanisms were discussed, and the excellent optical and mechanical properties of the ECTBN-modified blends could be attributed to the nanostructure formation and strong interfacial interactions.

Protection of aluminium foil AA8021 by molybdate-based conversion coatings

Co-reporter:Chang-Sheng Liang, Zhong-Fei Lv, Ye-Ling Zhu, Shi-Ai Xu, Hong Wang

Applied Surface Science 2014 Volume 288() pp:497-502

Publication Date(Web):1 January 2014

DOI:10.1016/j.apsusc.2013.10.060

Highlights

•: An environment-friendly molybdate-based coating for aluminium was developed.
•: The method is a highly effective and environment-friendly alternative to chromate coatings.
•: The method is very suitable for continuous processing.
•: The coating was mainly composed of MoO₃, (MoO₃)_x(P₂O₅)_y and Al₂(MoO₄)₃.
•: The corrosion resistance was investigated by EIS and potentiodynamic polarization.

Mechanical and thermal properties of novel rubber-toughened epoxy blend prepared by in situ pre-crosslinking

Co-reporter:Heng-Shi Zhou;Xiao-Xue Song

Journal of Applied Polymer Science 2014 Volume 131( Issue 22) pp:

Publication Date(Web):

DOI:10.1002/app.41110

ABSTRACT

A novel method is used for preparing liquid rubber-toughened epoxy blend, in which an initiator was added to the liquid rubber–epoxy mixture to initiate crosslinking reaction of liquid rubber, and then curing agent was added to form the thermoset. Two epoxy blends with carboxyl-terminated butadiene-acrylonitrile copolymers were prepared using traditional and novel methods respectively. Results indicated that the novel rubber-toughened epoxy blend exhibited much better mechanical properties than its traditional counterpart. The morphologies of the blends were explored by transmission electron microscopy (TEM), it was revealed that the use of the novel method formed a local interpenetrating network structure in the blend, which substantially improved the interfacial adhesion. The impact fracture surfaces of the two blends were observed by scanning electron microscopy (SEM) to explore the toughening mechanism, it was found that crack pinning was the major toughening mechanism for the novel rubber-toughened epoxy blend. Dynamic mechanical analysis (DMA) was applied to determine the T_g values of the blends, which were found to be close. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41110.

A new method to prepare rubber toughened epoxy with high modulus and high impact strength

Co-reporter:Hengshi Zhou, Shiai Xu

Materials Letters 2014 Volume 121() pp:238-240

Publication Date(Web):15 April 2014

DOI:10.1016/j.matlet.2014.01.160

•A novel method for preparing liquid rubber/epoxy composites is first reported.•The new composites possess higher yield strength and Young's modulus.•The new composites exhibit higher impact strength.Although epoxy resins can be substantially toughened by addition of a reactive liquid rubber, the improvement in toughness is inevitably accompanied by a significant loss in elastic modulus and yield strength. This paper presents a novel route for preparing the liquid rubber/epoxy composites with high yield strength, Young׳s modulus and impact strength. By this new method, the epoxy composites with different grades of carboxyl terminated butadiene acrylonitrile copolymer (CTBN) and cured by different curing agents were prepared, and their mechanical properties were characterized. It is found that no matter what grades of CTBN, also regardless of curing agents, the composites prepared by the new method always exhibit much higher impact strength, yield strength and Young׳s modulus than the corresponding traditional composites, proving the new method to be somewhat universal. Especially, some CTBN/epoxy composites exhibit even higher yield strength and Young׳s modulus than that of pure epoxy.

Synthesis and curing kinetics of cardanol-based curing agents for epoxy resin by in situ depolymerization of paraformaldehyde

Co-reporter:Yuan Liu;Juan Wang ;Shiai Xu

Journal of Polymer Science Part A: Polymer Chemistry 2014 Volume 52( Issue 4) pp:472-480

Publication Date(Web):

DOI:10.1002/pola.27018

ABSTRACT

Three novel cardanol-based phenalkamines with good stability have been successfully prepared by Mannich reaction using phenolic compounds with paraformaldehyde and hexamethylenediamine (or its mixture with other amines). The structure of the prepared phenalkamines has been analyzed using liquid chromatography-mass spectrometry, nuclear magnetic resonance, and Fourier transform infrared spectroscopy. The curing kinetics of the prepared epoxy resin/phenalkamine systems has been investigated using differential scanning calorimetry (DSC), and determined by Kissinger, Flynn–Wall–Ozawa, and Crane methods. Furthermore, the thermal properties of the cured materials have been evaluated using DSC and thermogravimetric analysis, and the mechanical properties of the cured materials have been analyzed systematically. The results demonstrate that the phenalkamine 1 (PAA1) had a lower reactivity and better toughness than phenalkamine 2 (PAA2) and phenalkamine 3 (PAA3). In addition, PAA1 is a solid curing agent, while PAA2 and PAA3 are liquid curing agents, which were more convenient for practical usage. Results indicate that the properties of the prepared phenalkamines strongly depend on the structures. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 472–480

Molybdate-based conversion treatment for improving the peeling strength between aluminum foil and polypropylene grafted with glycidyl methacrylate

Co-reporter:Chang-Sheng Liang, Zhong-Fei Lv, Ye-Ling Zhu, Shi-Ai Xu

Surface and Coatings Technology 2014 Volume 249() pp:1-5

Publication Date(Web):25 June 2014

DOI:10.1016/j.surfcoat.2014.03.038

•An environment friendly molybdate-based coating for aluminum was developed.•The T-peeling strength of the molybdate treated foil increased about 10 times.•The surface morphology of the Al foil after peeling was observed by SEM.•The foil surfaces were characterized by SEM, AFM, EDS and contact angle.This paper describes an environment-friendly treatment for aluminum (Al) foil that can greatly improve the adhesion strength between foil with the polymer film to a similar extent as the traditional chromate–phosphate treatment. Al foil was treated with different methods, after which a modified polypropylene (PP) film (PP grafted with glycidyl methacrylate, PP-g-GMA) was directly joined with the treated Al foil by hot pressing. The T-peeling strengths of the Al/PP-g-GMA composites were measured, and the peeling strength of molybdate-treated foil was found to be approximately 10 times greater than that of untreated foil. The surface morphologies of the Al foils were observed by scanning electron microscopy and atomic force microscope, their chemical compositions were characterized by energy-dispersive spectroscopy. The hydrophilicities and surface energies of the treated Al foils were further evaluated by contact-angle measurements.

Effect of surface pre-treatment on the hydrophilicity and adhesive properties of multilayered laminate used for lithium battery packaging

Co-reporter:F. Xia, S.A. Xu

Applied Surface Science 2013 Volume 268() pp:337-342

Publication Date(Web):1 March 2013

DOI:10.1016/j.apsusc.2012.12.091

Abstract

The surface of aluminum foil was treated using silane coupling agent and chromate–phosphate conversion solution respectively, then a flexible laminate consisting of five layers was prepared using polypropylene film as inner sealant layer and epoxy resin as adhesive between polypropylene film and aluminum foil. The surface morphology and composition of the foil after treatment were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and the hydrophilicity of the foil was evaluated by contact angle measurement (CAM). The adhesive strength between the aluminum foil and polypropylene film, and the heat sealing strength of polypropylene film were measured by tensile tester, their dependences on the surface treatments were further investigated. It can be concluded that the adhesive strength and heat sealing strength depend on not only the hydrophilicity, but also the morphology of the foil surface. The rough and porous surface of the treated foil can enhance both the adhesive strength and heat sealing strength.

Synergism effect between modified carbon black and organic ultraviolet absorber in polymer matrix for ultraviolet protection

Co-reporter:Q. F. Shi;J. Y. Gao;D. D. Zhao;S. A. Xu

Journal of Applied Polymer Science 2010 Volume 116( Issue 5) pp:2566-2572

Publication Date(Web):

DOI:10.1002/app.31775

Abstract

Modified carbon black (MCB) was obtained by oxidization and hydroxymethylation reactions with conductive carbon black (CB); in the MCB, some hydroxyl groups were introduced on the surface of the CB particles. CB, MCB, and a kind of organic ultraviolet absorber (UA) were used as UV antidotes, and binary composites and ternary composites were prepared by solvent casting with polystyrene, styrene–butadiene–styrene triblock copolymer, and poly(methyl methacrylate) as the matrix, respectively. In the binary composites, only one kind of UV antidote was used, whereas in the ternary composites, the organic and inorganic UAs were combined. The ultraviolet–visible absorption spectra of the composites were investigated extensively, and it was found that no synergism occurred when CB was combined with the organic absorber; on the other hand, an obvious synergism effect emerged when MCB was combined with the organic absorber in the same matrix, which was attributed to the formation of hydrogen bonds between MCB and UA. The interaction between MCB and UA was studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Effect of ultrasonic separation on the structure and properties of diallyl phthalate prepolymer

Co-reporter:Shi-Ai Xu, Ming He, Qing-Feng Shi, Guo-Cheng Jin, Jun-Qi Yao, Ruo-Bing Yu, Chi-Fei Wu

Ultrasonics Sonochemistry 2008 Volume 15(Issue 4) pp:364-369

Publication Date(Web):April 2008

DOI:10.1016/j.ultsonch.2007.07.012

Preparation and characterization of poly(methyl methacrylate) and poly(maleic anhydride-co-diallyl phthalate) grafted carbon black through γ-ray irradiation

Co-reporter:Yang Bo, Jiayang Cui, Yangben Cai, Shiai Xu

Radiation Physics and Chemistry (February 2016) Volume 119() pp:236-246

Publication Date(Web):1 February 2016

DOI:10.1016/j.radphyschem.2015.11.005

•The influence of monomer activity on the grafting of CB was investigated.•Methyl methacrylate was grafted onto CB surface through γ-ray irradiation.•Diallyl phthalate was used to assist grafting of maleic anhydride onto CB surface.•The grafted CBs have smaller size and better dispersibility.In this study, the grafting polymerization of methyl methacrylate (MMA) monomer and maleic anhydride/diallyl phthalate (MAH/DAP) co-monomer onto the surface of carbon black (CB) were carried out at room temperature and normal pressure by γ-ray irradiation. The surface chemistry of grafted CBs were characterized by infrared spectroscopy (IR), thermo-gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The results show that there are some remanent polymers on the surface of modified CBs after extract for 48 h, indicating that poly(methyl methacrylate) (PMMA) and poly(MAH-co-DAP) have been successfully grafted onto the surface of CB without using initiator due to the high energy of γ-ray irradiation. Dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the grafted CBs have smaller average aggregate size and better dispersibility than that of CB in absolute ethanol. In addition, it was found that the amount of oxygen groups and the irradiation doses/dose rates have little effect on the grafting degree of CB.

Mechanical Properties and Interfacial Interaction of Modified Calcium Sulfate Whisker/Poly(Vinyl Chloride) Composites

Co-reporter:Wenjin Yuan, Jiayang Cui, Shiai Xu

Journal of Materials Science & Technology (December 2016) Volume 32(Issue 12) pp:

Publication Date(Web):1 December 2016

DOI:10.1016/j.jmst.2016.05.016

Calcium sulfate whiskers (CSWs) modified with glutaraldehyde-crosslinked poly(vinyl alcohol) (PVA) or traditional surface modifiers, including silane coupling agent, titanate coupling agent and stearic acid, were used to strengthen poly(vinyl chloride) (PVC), and the morphologies, mechanical and heat resistant properties of the resulting composites were compared. The results clearly show that glutaraldehyde cross-linked PVA modified CSW/PVC composite (cPVA@CSW/PVC) has the strongest interfacial interaction, good and stable mechanical and heat resistant properties. Nielsen's modified Kerner's equation for Young's modulus is better than other models examined for the CSW/PVC composites. The half debonding angle θ of cPVA@CSW/PVC composite is lower than that of other composites except silane coupling agent modified CSW/PVC composites, indicating a very strong interfacial adhesion between cPVA@CSW and PVC. In general, cross-linked PVA is effective and environmentally friendly in modifying inorganic fillers.