HongXia Yan

Nonconventional fluorescent polymers without π-aromatic structure have attracted extensive interest in recent years. Hyperbranched polyesters are generally known because of their industrial applications; however, the luminescent properties of the polyester has not been reported. Herein, we synthesized a series of fully biobased aliphatic hyperbranched polyesters via a one-pot A2 + B3 esterification reaction. Intriguingly, the resultant hyperbranched polyesters carrying no conventional fluorescent units exhibited unexpected bright blue fluorescence under 365 nm UV light. It was found that the fluorescence intensity was enhanced with increasing solution concentrations and molecular weights of the polyesters. Moreover, the results suggested that the luminescence of polyesters could be controlled by solvents and metal ions. In particular, the fluorescence of the polyesters was extremely sensitive to Fe3+. More interesting is that the fluorescence of the polyesters showed an aggregation-induced enhanced emission in the mixture system. Notably, the resulting polyesters displayed a remarkably enhanced quantum yield (16.75%) as compared with that of other types of these polymers. Preliminary results demonstrate that clustering of the carbonyl groups is responsible for the unusual fluorescence in the aliphatic hyperbranched polyesters, namely, clustering-induced emission (CIE). This study provides a novel perspective for the design of biobased luminescent materials to new application areas.Keywords: Biomass materials; Blue light; Clustering-induced emission (CIE); Fluorescent hyperbranched polyester;

Ternary hybrid nanoparticles of reduced graphene oxide/graphene-like MoS2/zirconia as lubricant additives for bismaleimide composites with improved mechanical and tribological properties

Co-reporter:Zhengyan Chen, Hongxia Yan, Qing Lyu, Song Niu, Cheng Tang

Composites Part A: Applied Science and Manufacturing 2017 Volume 101(Volume 101) pp:

Publication Date(Web):1 October 2017

DOI:10.1016/j.compositesa.2017.06.008

To develop low friction coefficient and high wear resistance composites, the ternary hybrid nanoparticles consisting of reduced graphene oxide (rGO), graphene-like MoS2 and ZrO2 with active amino groups (NH2-rGO/MoS2/ZrO2) were successfully prepared through a facile and effective one-pot hydrothermal method. Subsequently, the bismaleimide (BMI) composites with different weight fraction of fillers were fabricated to enhance the mechanical and tribological properties of BMI resin. The results demonstrate that the layers of MoS2 in the filler can significantly decrease and just a little content of fillers can remarkably improve the mechanical and tribological properties of BMI resin. In particular, the average friction coefficient and volume wear rate of the BMI composite containing 0.4 wt.% NH2-rGO/MoS2/ZrO2 can reach the lowest value of 0.15 and 1.5 × 10−6 mm3/(N·m), respectively. The excellent friction-reducing and wear-resistance performances are mainly attributed to the good synergistic effect among the rGO nanosheets, graphene-like MoS2 and ZrO2.To develop low friction coefficient and high wear resistance composites, the ternary hybrid nanoparticles consisting of reduced graphene oxide (rGO), graphene-like MoS2 and ZrO2 with active amino groups (NH2-rGO/MoS2/ZrO2) were successfully prepared through a facile and effective one-pot hydrothermal method. Subsequently, the bismaleimide (BMI) composites with different weight fraction of fillers were fabricated to enhance the mechanical and tribological properties of BMI resin. The results demonstrate that the layers of MoS2 in the filler can significantly decrease and just a little content of fillers can remarkably improve the mechanical and tribological properties of BMI resin. In particular, the average friction coefficient and volume wear rate of the BMI composite containing 0.4 wt.% NH2-rGO/MoS2/ZrO2 can reach the lowest value of 0.15 and 1.5 × 10−6 mm3/(N·m), respectively. The excellent friction-reducing and wear-resistance performances are mainly attributed to the good synergistic effect among the rGO nanosheets, graphene-like MoS2 and ZrO2.Download high-res image (57KB)Download full-size image

High toughening and low friction of novel bismaleimide composites with organic functionalized serpentine@Fe3O4

Co-reporter:Xiaoli Zhi;Song Li;Song Niu;Chao Liu

Journal of Polymer Research 2017 Volume 24( Issue 2) pp:

Publication Date(Web):2017 February

DOI:10.1007/s10965-017-1192-9

A novel hybrid particles Srp@Fe3O4/OA, composed of phyllosilicate Serpentine (Srp), magnetic Fe3O4 and oleic acid (OA), has been explored via a two-step process. Then the as-prepared Srp@Fe3O4/OA particles were firstly mixed with bismaleimide resin (BMI) to constructe a series of Srp@Fe3O4/OA/BMI composites, the mechanical properties, tribological properties and thermal stability of the Srp@Fe3O4/OA/BMI composites are subsequently investigated. The characterization results indicate that the 0.3 wt% Srp@Fe3O4/OA/BMI composite shows the maximum impact strength (19.0 kJ·m−2) and minimum friction coefficient (0.21), higher 52.7% and lower 55% than those of the neat BMI resin, respectively. The significantly enhanced toughness and tribological performance of the Srp@Fe3O4/OA/BMI composites are mainly due to the increase of the free volume and the uniformly distribution of Srp@Fe3O4/OA, as well as the good interfacial adhesion between BMI matrix and Srp@Fe3O4/OA particles.

A multifunctional silicon-containing hyperbranched epoxy: controlled synthesis, toughening bismaleimide and fluorescent properties

Co-reporter:Song Niu, Hongxia Yan, Song Li, Cheng Tang, Zhengyan Chen, Xiaoli Zhi and Peilun Xu

Journal of Materials Chemistry A 2016 vol. 4(Issue 28) pp:6881-6893

Publication Date(Web):27 Jun 2016

DOI:10.1039/C6TC02546C

A novel silicon-containing hyperbranched epoxy (SHBEp) has been explored via a one-pot A2 + B3 polycondensation reaction using (3-glycidyloxypropyl)trimethoxysilane (A-187) and excess neopentyl glycol (NPG) under solvent-free and catalyst-free conditions. We investigate for the first time bismaleimide (BMI) toughening effect using the fabricated polymer, and a series of SHBEp/BMI thermosets are then constructed, and then their mechanical properties like impact strength, flexural strength, and thermal stability are studied; meanwhile the toughening effect of SHBEp and conventional epoxy resin E51 is also compared. The results indicate that a proper addition of SHBEp (8 wt%) can significantly improve the toughness and thermal performance of thermosets compared to E51 with the same content. It is, therefore, revealed that the polymer is promising to act as an effective BMI toughener. Unexpectedly, a bright blue photoluminescence is observed when the SHBEp is excited under 365 nm UV light, and its average fluorescence lifetime and absolute fluorescence quantum yield are 4.30 ns and 4.61% respectively. It is demonstrated by our primary investigation that the epoxide and hydroxyl groups simultaneously help the light emission. Thus, the SHBEp bearing unconventional chromophores is also particularly expected to be a new light-emitting material.

Unanticipated bright blue fluorescence produced from novel hyperbranched polysiloxanes carrying unconjugated carbon–carbon double bonds and hydroxyl groups

Co-reporter:Song Niu, Hongxia Yan, Zhengyan Chen, Song Li, Peilun Xu and Xiaoli Zhi

Polymer Chemistry 2016 vol. 7(Issue 22) pp:3747-3755

Publication Date(Web):03 May 2016

DOI:10.1039/C6PY00654J

One-pot polycondensation reaction of triethoxyvinylsilane (A-151) with excessive neopentyl glycol (NPG) is employed as an efficient and facile methodology for the synthesis of novel hyperbranched polysiloxanes contemporaneously bearing plenty of unconjugated carbon–carbon double bonds and hydroxyl groups (HPUHs). Interestingly, the obtained HPUHs obviously without containing conventional chromophores exhibit conspicuous ultraviolet absorbency and bright blue photoluminescence when irradiated by a UV lamp with 365 nm wavelength. The excitation and emission intensities of the as-prepared polymers progressively grow along with raising their molecular weights and concentrations, and even the brightest blue glow in the solid state is observed, suggesting the emission intensity is molecular-weight and concentration-dependent. The preliminary investigation indicates that both the carbon–carbon double bond and the hydroxyl group are very important in the formation of blue-luminescent species. Thus, this work opens a new route to design new light-emitting materials.

Enhanced tribological properties of aligned reduced graphene oxide-Fe3O4@polyphosphazene/bismaleimides composites

Co-reporter:Chao Liu, Hongxia Yan, Qing Lv, Song Li, Song Niu

Carbon 2016 Volume 102() pp:145-153

Publication Date(Web):June 2016

DOI:10.1016/j.carbon.2016.02.021

By taking advantage of design and construction of strong graphene–matrix interfaces, a ternary nanoparticle (GNS-Fe3O4@PZM) consisting of graphene, Fe3O4 nanoparticles and highly cross-linked polyphosphazene has been synthesized via a two-stage process consisting of co-precipitation and precipitation polymerization. And then the bismaleimide (BMI) matrix composites with aligned GNS-Fe3O4@PZM are fabricated under a magnetic field to take full advantage of the tribological properties of graphene. Characterization results reveal that the 0.8 wt% aligned GNS-Fe3O4@PZM/BMI composite has the lowest friction coefficient and volume wear rate compared with non-aligned GNS-Fe3O4@PZM/BMI and aligned GNS-Fe3O4/BMI composites under all the test conditions. In addition, the aligned GNS-Fe3O4@PZM/BMI also shows superior mechanical properties and thermal stability. The excellent properties of aligned GNS-Fe3O4@PZM/BMI result from uniformly distribution and parallel alignment of graphene in the BMI matrix, as well as good interface interaction between GNS-Fe3O4@PZM and BMI matrix.

Water-Soluble Blue Fluorescence-Emitting Hyperbranched Polysiloxanes Simultaneously Containing Hydroxyl and Primary Amine Groups

Co-reporter:Song Niu;Zhengyan Chen;Lingxia Yuan;Tianye Liu;Chao Liu

Macromolecular Rapid Communications 2016 Volume 37( Issue 2) pp:136-142

Publication Date(Web):

DOI:10.1002/marc.201500572

Nanosheets of MoS2 and reduced graphene oxide as hybrid fillers improved the mechanical and tribological properties of bismaleimide composites

Co-reporter:Zhengyan Chen, Hongxia Yan, Tianye Liu, Song Niu

Composites Science and Technology 2016 Volume 125() pp:47-54

Publication Date(Web):23 March 2016

DOI:10.1016/j.compscitech.2016.01.020

The hybrid nanoparticles composed of reduced graphene oxide and MoS2 nanosheets with active amino groups (NH2-rGO/MoS2) were fabricated by a facile and effective method. Then the bismaleimide (BMI) composites filled with the as-prepared NH2-rGO/MoS2 nanoparticles were obtained by a casting method. The microstructure and morphology of NH2-rGO/MoS2 nanoparticles, the mechanical properties, thermal property and tribological properties of NH2-rGO/MoS2/BMI composites were investigated. The results show that the interlaminar distance of MoS2 nanosheets in the hybrid nanoparticles is 0.71 nm, which is much larger than that of bulk MoS2 (0.62 nm); and the NH2-rGO/MoS2/BMI composites possess better friction-reducing and anti-wear performances (the friction coefficient and volume wear rate are about 0.2 and 2.9 × 10−6 mm3/(N·m), respectively) compared to the neat BMI resin. This is mainly attributed to the enhanced toughness of the nanoparticles, good interfacial adhesion between NH2-rGO/MoS2 and BMI matrix as well as the synergistic effect between rGO and MoS2 nanosheets.

Effect of functionalized graphene oxide with hyperbranched POSS polymer on mechanical and dielectric properties of cyanate ester composites

Co-reporter:Mengmeng Zhang, Hongxia Yan, Lingxia Yuan and Chao Liu

RSC Advances 2016 vol. 6(Issue 45) pp:38887-38896

Publication Date(Web):13 Apr 2016

DOI:10.1039/C6RA01053A

In this paper, a hyperbranched silsesquioxane polymer grafted graphene oxide (HPP-GO) was fabricated successfully. Hexamethylenediamine was firstly grafted onto the graphene oxide sheets. Then chloropropyl silsesquioxane and hexamethylenediamine were repeatedly grafted onto the hexamethylenediamine coated graphene oxide, which was confirmed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectra, X-ray diffraction and transmission electron spectroscopy. Subsequently, the HPP-GO was incorporated into dicyclopentadiene bisphenol dicyanate ester (DCPDCE) to prepare composites. The effects of HPP-GO on the mechanical, dynamic mechanical, dielectric and thermal properties of DCPDCE resin were investigated systematically. Results show that the appropriate content of HPP-GO can enhance the mechanical properties including impact and flexural strengths of DCPDCE resin. When HPP-GO content is 0.6 wt%, the corresponding composite exhibits higher storage modulus, glass transition temperature and onset degradation temperature values than pure DCPDCE resin. In addition, the dielectric constant and loss of HPP-GO/DCPDCE composites are decreased with the increasing content of HPP-GO. These attractive properties of HPP-GO/DCPDCE composites suggest that the method proposed herein is effective to prepare high-performance graphene oxide/polymer composites.

Bright Blue Photoluminescence Emitted from the Novel Hyperbranched Polysiloxane-Containing Unconventional Chromogens

Co-reporter:Song Niu;Song Li;Peilun Xu;Xiaoli Zhi;Tingting Li

Macromolecular Chemistry and Physics 2016 Volume 217( Issue 10) pp:1185-1190

Publication Date(Web):

DOI:10.1002/macp.201500537

A Derivative of s-Triazine Modified Reduced Graphene Oxide with the Function of UV-absorbing

Co-reporter:Tianye Liu;Zhengyan Chen;Peilun Xu ;Shikun Su

Chinese Journal of Chemistry 2016 Volume 34( Issue 1) pp:123-128

Publication Date(Web):

DOI:10.1002/cjoc.201500506

Abstract

A new s-triazine derivative modified graphene composite, in which 2,4,6-tri(2,4-dihydroxyphenyl)-1,3,5-triazine (TDTA) was attached onto reduced graphene oxide (rGO) via the noncovalent functionalization approach, named TDTA/rGO, was reported. And the TDTA was synthesized via a Friedel-Crafts reaction. FTIR and NMR spectroscopic characterizations were carried out to confirm the synthesis of TDTA. UV-Vis, XPS and TEM revealed that TDTA molecules were successfully loaded onto graphene sheets by π-π stacking, and the composite is found to improve greatly the dispersity of rGO in DMF and to be a good UV-absorber.

Phosphorus-containing flame-retardant bismaleimide resin with high mechanical properties

Co-reporter:Song Li;Shuyao Feng;Xu Li

Polymer Bulletin 2016 Volume 73( Issue 12) pp:3547-3557

Publication Date(Web):2016 December

DOI:10.1007/s00289-016-1692-5

Novel flame-retardant bismaleimides-based composites (P-DBA/DBE/BMIs) with excellent mechanical properties and processibility were developed by phenylphosphonic dichloride (PPD), diallyl bisphenol A (DBA), diallyl bisphenol A ether (DBE) and bismaleimide. In this system, PPD acts as a reactive flame retardant, which endows bismaleimide with excellent flame retardancy and thermal stability; DBE can improve the processibility of bismaleimide resin, and rearrange into DBA to react with bismaleimides at high temperature. Compared to the impact and flexural strength of conventional bismaleimide resin modified only by 42.86 wt% DBA, those of P-DBA/DBE/BMIs with 1.00 wt% PPD, 7.14 wt% DBE and 35.72 wt% DBA, respectively, increased 31.92 and 63.36 %. Furthermore, the thermal stability was improved markedly, and the flame-retarding UL-94 rating was increased from V-1 to V-0.

Novel phosphorus-containing polyhedral oligomeric silsesquioxane designed for high-performance flame-retardant bismaleimide resins

Co-reporter:Song Li;Cheng Tang;Song Niu;Yuan Jia

Journal of Polymer Research 2016 Volume 23( Issue 11) pp:

Publication Date(Web):2016 November

DOI:10.1007/s10965-016-1133-z

A novel phosphorus-containing polyhedral oligomeric silsesquioxane (P-POSS) was developed, and incorporated into O, O′-diallylbisphenol A-modified bismaleimide (DBMI) to prepare slightly foaming flame-retardant materials (P-POSS/DBMI). The curing reaction, mechanical properties, thermal stability and flame retardancy of P-POSS/DBMI were systematically studied. The result of dynamic FTIR confirmed that the P-POSS could participate in the curing reaction of DBMI. In addition, it was proved that the material with a very low content of the P-POSS exhibited remarkably improved thermal stability and flame retardancy. When 6.0 wt.% P-POSS was introduced into DBMI matrix, char yield at 800 °C increased by ~31.5 %, meanwhile UL-94 V-0 rating and 35.4 LOI (limiting oxide index) were also obtained. And compared with DBMI, the flexural strength and impact strength of 6.0 wt.% P-POSS/DBMI were enhanced 42.3 % and 30.8 %, respectively. Interestingly, the impact strength of 2.0 wt.% P-POSS/DBMI increased to 30.5 kJ/m2, about 136 % higher than that of DBMI.

Synthesis of a novel phosphorus-containing benzoxazine-monomer and its polymer alloys based on bismaleimides

Co-reporter:Song Li;Hong-xia Yan;Yuan Jia;Tian-ye Liu

Journal of Polymer Research 2016 Volume 23( Issue 9) pp:

Publication Date(Web):2016 September

DOI:10.1007/s10965-016-1030-5

To improve the flame resistance properties and thermal properties of bismaleimides (BMI) resin, a reactive phosphorus-contained benzoxazine monomer (PBOZ) was synthesized based on a phosphorus-containing compound 10-(2, 5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(ODOPB), and its chemical structure was characterized by infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). The novel PBOZ monomer was then used to blend with BMI (PBOZ-BMI), and the flame resistance of PBOZ-BMI resin was evaluated by the vertical flame test and the limited oxygen index (LOI) test. The results showed that the PBOZ-BMI exhibits better flame resistance. The thermal properties of cured PBOZ-BMI resins were investigated by differential scanning calorimeter (DSC) and thermogravimetry (TG). DSC results showed that the curing temperatures of PBOZ-BMI resins decreased with suitable content of PBOZ in comparison with BMI. The TGA result showed that the onset decomposition temperatures and the char yields also increased with the suitable addition of PBOZ. These conclusions can further confirms that the flame resistance of PBOZ-BMI enhanced as its thermal properties increase.

Synthesis of functionalized GO for improving the dielectric properties of bismaleimide-triazine resin

Co-reporter:Lihua Bai;Lingxia Yuan;Chao Liu

Journal of Polymer Research 2016 Volume 23( Issue 8) pp:

Publication Date(Web):2016 August

DOI:10.1007/s10965-016-1071-9

A type of functionalized graphene oxide (GO), named GO-POSS-BPA, was synthesized by nucleophilic substitution reaction with chloropropyl polyhedral oligomeric silsesquioxanes (POSS) and bisphenol A (BPA). Subsequently, the GO-POSS-BPA was added into bismaleimide-triazine (BT) resin to improve dielectric properties of bismaleimide-triazine resin. The structure of GO-POSS-BPA was characterized by Fourier-transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopic (TEM). The effects of GO-POSS-BPA on the dielectric, mechanical, thermal and water resistant properties of BT resin were investigated systematically. The results show that, GO-POSS-BPA decreased the dielectric constant and dielectric loss of BT resin over the testing frequency from 10 to 50 MHz, also enhanced the stability of dielectric constant. Meanwhile, the appropriate content of GO-POSS-BPA can enhance the impact and flexural strengths of BT resin to a certain extent. In addition, GO-POSS-BPA can also enhance the thermal stability and moisture resistance of BT resin.

Mechanical properties of cyanate ester composites modified by ESi

Co-reporter:Qian Li;Xiang-Ting Wang;Hong-Xia Yan

Polymer Bulletin 2016 Volume 73( Issue 8) pp:2343-2352

Publication Date(Web):2016 August

DOI:10.1007/s00289-016-1611-9

In this study, bisphenol A dicyanate ester (BCE) was modified with epoxy group silane (ESi) to improve the impact strength of neat resin specimens. The ESi/BCE composites were shown to have better impact strength and flexural strength properties than un-modified samples. When the value of Tg was not significantly changed, in comparison to the neat BCE, the impact and flexural strength of modified resins increased by 43.5 and 31.7 %, respectively. ESi reinforced the toughness of the BCE, which was confirmed by scanning electronic microscopy. Mechanical properties were improved primarily due to epoxy group reactions in ESi and cyanate groups in BCE, confirmed by FTIR.

Enhanced tribological properties of bismaleimides filled with aligned graphene nanosheets coated with Fe3O4 nanorods

Co-reporter:Chao Liu, Hongxia Yan, Zhengyan Chen, Lingxia Yuan and Tianye Liu

Journal of Materials Chemistry A 2015 vol. 3(Issue 19) pp:10559-10565

Publication Date(Web):02 Apr 2015

DOI:10.1039/C5TA00797F

Hybrid particles composed of reduced graphene oxide sheets (GNSs) coated with Fe3O4 nanorods (GNS–Fe3O4) were synthesized through a facile coprecipitation route. Bismaleimide (BMI) composites were then prepared with the aligned GNS–Fe3O4 hybrid particles by a casting method, and the effect of the GNS–Fe3O4 hybrid particles on the mechanical and tribological properties of the composites was investigated. It was found that the BMI composites with the aligned GNS–Fe3O4 exhibited thermal stability, as well as excellent mechanical and tribological properties, such as friction coefficients as low as 0.07 with 0.6 wt% GNS–Fe3O4. This is mainly due to the fact that the aligned GNS–Fe3O4, with its layered structure, can effectively reduce the friction coefficient due to the good synergy between the graphene and Fe3O4 during the wear process. The obtained results indicate that the magnetic alignment of GNS–Fe3O4 is an effective method for greatly improving the friction and wear properties of resin-based composites.

Novel Hyperbranched Polysiloxanes Containing Acetoacetyl Groups Synthesized Through Transesterification Reaction

Co-reporter:Song Niu

Macromolecular Rapid Communications 2015 Volume 36( Issue 8) pp:739-743

Publication Date(Web):

DOI:10.1002/marc.201400585

Synthesis and characterization of a phosphorus-containing flame retardant with double bonds and its application in bismaleimide resins

Co-reporter:Song Li, Hongxia Yan, Shuyao Feng and Song Niu

RSC Advances 2015 vol. 5(Issue 123) pp:101480-101486

Publication Date(Web):12 Nov 2015

DOI:10.1039/C5RA15946F

A novel phosphorus-containing flame retardant, bis(4-(allyloxy)phenyl)phenylphosphonate (APP) has been synthesized. The structure of APP has been systemically characterized using Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR and 31P NMR). Subsequently, APP was added into bismaleimide (BMI) resin to prepare flame retardant materials, coded as P-DBMI resin. The effects of APP content on the mechanical properties of the P-DBMI resins have been studied. In addition, thermogravimetric kinetics, UL-94 tests, limited oxygen index (LOI), scanning electron microscopy and residual analysis were carried out to reveal the thermal properties and flame retardancy of P-DBMI resin. The results indicate that P-DBMI resin with good mechanical properties, thermal stability and flame retardancy were obtained.

Improved mechanical and tribological properties of bismaleimide composites by surface-functionalized reduced graphene oxide and MoS2 coated with cyclotriphosphazene polymer

Co-reporter:Zhengyan Chen, Hongxia Yan, Tianye Liu, Song Niu and Jiayi Ma

RSC Advances 2015 vol. 5(Issue 118) pp:97883-97890

Publication Date(Web):03 Nov 2015

DOI:10.1039/C5RA19101G

Surface-functionalized reduced graphene oxide and MoS2 hybrid nanosheets (rGO/MoS2) were obtained with a poly-(cyclotriphosphazene-co-4,4′-diaminodiphenylmethane) (PZD) polymer coating by a one-pot noncovalent method. The PZD/rGO/MoS2 hybrid nanoparticles were then chosen as fillers to improve the mechanical and tribological properties of bismaleimide (BMI) resin. The results showed that suitable addition of PZD/rGO/MoS2 could greatly enhance not only the mechanical and tribological properties but also the thermal stability. A low friction coefficient of 0.06 and volume wear rate of 1.80 × 10−6 mm3 (N m)−1 with 0.4 wt% PZD/rGO/MoS2 were obtained. This is mainly attributed to the unique layered structure of PZD/rGO/MoS2 hybrid nanoparticles, the enhanced toughness of the composites, good interfacial adhesion and compatibility between PZD/rGO/MoS2 and the BMI matrix, as well as the synergistic effect between nanosheets of rGO and MoS2.

Hyperbranched polysiloxane grafted graphene for improved tribological performance of bismaleimide composites

Co-reporter:Hongxia Yan, Song Li, Yuan Jia and Xiao Yan Ma

RSC Advances 2015 vol. 5(Issue 17) pp:12578-12582

Publication Date(Web):05 Jan 2015

DOI:10.1039/C4RA13134G

Hyperbranched polysilane (HBPSi) grafted reduced graphene oxide (rGO), marked as HBPSi-rGO, was synthesized by the reaction of hydrosilylation. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) indicated that the surface of graphene had been successfully functionalized. Subsequently, HBPSi-rGO was incorporated into the bismaleimides (BMI) resin to prepare composites so as to improve its performance. The tribological, mechanical and thermal properties of the composites were studied systematically. Results show that the addition of the appropriate content of HBPSi-rGO can enhance the mechanical properties including the impact and flexural strengths of the BMI resin. In addition, the thermal stability of HBPSi-rGO/BMI nanocomposites is also superior to that of the pure BMI resin. It is worth noting that when the content of HBPSi-rGO is 0.6 wt%, the frictional coefficient and the wear rate is decreased by 44.6% and 77.4%, respectively compared to those of the neat BMI. Scanning electron microscopy (SEM) reveals that wear mechanism of neat BMI is mainly fatigue wear, but it turns mainly adhesive wear after the incorporation of HBPSi-rGO. The main reason can be that the interface adhesion was enhanced due to the reaction of nucleophilic addition between HBPSi-rGO and BMI matrix.

Preparation and characterization of POSS-SiO2/cyanate ester composites with high performance

Co-reporter:Mengmeng Zhang;Chao Liu ;Junping Zhang

Polymer Composites 2015 Volume 36( Issue 10) pp:1840-1848

Publication Date(Web):

DOI:10.1002/pc.23091

In this article, a hybrid filler based on polyhedral oligomeric silsesquioxane and silica, coded as POSS-SiO₂, has been successfully synthesized. The structure of POSS-SiO₂ was studied by Fourier-transform infrared spectra, X-ray diffraction, and scanning electron microscopy. Then the POSS-SiO₂ was compounded with dicyclopentadiene bisphenol dicyanate ester (DCPDCE) resin to prepare composites. The effects of POSS-SiO₂ on the curing reaction, mechanical, thermal, dielectric and tribological properties of DCPDCE resin were investigated systematically. Results of differential scanning calorimetry show that the addition of POSS-SiO₂ can facilitate the curing reaction of DCPDCE and decrease the curing temperature of DCPDCE. Compared with pure DCPDCE resin, the impact and flexural strengths of the composites materials are improved markedly with up to 72 and 52% increasing magnitude, respectively. Meanwhile, the POSS-SiO₂/DCPDCE systems exhibit lower dielectric constant and loss than pure DCPDCE resin over the testing frequency from 10 to 60 MHz. In addition, the thermal stability and tribological properties of POSS-SiO₂/DCPDCE composites are also superior to that of pure DCPDCE resin. POLYM. COMPOS., 36:1840–1848, 2015. © 2014 Society of Plastics Engineers

Hyperbranched polytriazine grafted reduced graphene oxide and its application

Co-reporter:Chao Liu;Lingxia Yuan;Zhengyan Chen ;Mengmeng Zhang

Journal of Polymer Science Part A: Polymer Chemistry 2015 Volume 53( Issue 18) pp:2132-2140

Publication Date(Web):

DOI:10.1002/pola.27661

ABSTRACT

In this article, cyanuric chloride (CC) and hexamethylenediamine (HMD) as raw material, the grafting of hyperbranched polytriazine onto reduced graphene oxide surface (HBP-RGO) was achieved by the repeated nucleophilic substitution between chlorine groups of CC and amino groups of HMD, respectively. The Fourier transform infrared, X-ray photoelectron spectroscopic, Raman, transmission electron microscopic, thermogravimetric, and atomic force microscopic analysis showed that HBP-RGO had been successfully prepared and the HBP had a dendritic structure on the surface of RGO. And then, the HBP-RGO was added into polystyrene (PS) and the HBP-RGO/PS composite was prepared by solution mixing. The micro-morphology, thermal stability, and electrical conductivity of RGO/PS and HBP-RGO/PS composites were characterized and compared. The scanning electron microscopic analysis showed that the HBP-RGO can uniformly disperse in PS. Meanwhile, the HBP-RGO/PS composite showed good thermal stability and electrical conductivity, the percolation threshold of the composites is low as 0.32 vol %. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2132–2140

Effect of functionalized graphene oxide with a hyperbranched cyclotriphosphazene polymer on mechanical and thermal properties of cyanate ester composites

Co-reporter:Mengmeng Zhang, Hongxia Yan, Xiaowei Yang and Chao Liu

RSC Advances 2014 vol. 4(Issue 86) pp:45930-45938

Publication Date(Web):17 Sep 2014

DOI:10.1039/C4RA06411A

In this paper, graphene oxide (GO) was functionalized with a hyperbranched cyclotriphosphazene polymer, which was synthesized by the repeated reactions of hexachlorotriphosphazene with hexamethylenediamine. Subsequently, the resultant functionalized GO was incorporated into dicyclopentadiene bisphenol dicyanate ester (DCPDCE) to prepare composites. Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron spectroscopy were employed to examine the surface functionalization of GO. The effects of functionalized GO on the curing reactivity, mechanical, dielectric, thermal and water resistent properties of DCPDCE resin were investigated systematically. Results show that the addition of modified GO can facilitate the curing reaction of DCPDCE. Meanwhile, the appropriate content of modified GO can enhance the mechanical properties including impact and flexural strengths of DCPDCE resin. When modified GO content is 0.6 wt%, the corresponding composite exhibits slightly higher dielectric constant but lower dielectric loss than pure DCPDCE resin over the testing frequency from 10 to 60 MHz. In addition, the thermal stability and moisture resistance of modified GO/DCPDCE nanocomposties are also superior to that of pure DCPDCE resin.

Improvement of interfacial adhesion between PBO fibers and cyanate ester matrix

Co-reporter:Hongxia Yan;Shuyao Feng;Zijun Zhang ;Sihai Hu

Journal of Applied Polymer Science 2014 Volume 131( Issue 9) pp:

Publication Date(Web):

DOI:10.1002/app.40204

ABSTRACT

Poly(p-phenylene benzobisoxazole) (PBO) fibers were activated by the horseradish peroxidases (HRP) and then treated by 3-Glycidoxypropyltrimethoxysilane (KH-560) to improve the wettability and the interfacial adhesion between PBO fibers and cyanate ester matrix. The chemical compositions of PBO fibers were characterized and analyzed by FTIR and XPS. Surface morphologies of PBO fibers were examined by SEM. The wettability of PBO fibers was evaluated by the dynamic contact angle analysis test. The mechanical properties were evaluated by tensile strength and interfacial shear strength, respectively. The results demonstrated that hydroxyl groups and epoxy groups were introduced onto the surface of PBO fibers during the treatments. These treatments can effectively improve the wettability and adhesion of PBO fibers. The surface free energy of PBO fibers was increased from 31.1 mN/m to 55.2 mN/m, and the interfacial adhesion between PBO fiber and cyanate ester resin was improved to 10.77 MPa. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40204.

Improved mechanical and tribological properties of benzoxazine-bismaleimides resin by surface-functionalized carbon nanotubes

Co-reporter:Yuan Jia;Hong-xia Yan;Lei Ma;Jun-Ping Zhang

Journal of Polymer Research 2014 Volume 21( Issue 7) pp:

Publication Date(Web):2014 July

DOI:10.1007/s10965-014-0499-z

Surface-functionalized multiwall carbon nanotubes (ESi-MWCNTs) were obtained from hydrolysis of γ-(2,3-epoxypropoxy) propytrimethoxysilane to graft hyperbranched polysiloxane on the surface of multiwall carbon nanotubes (MWCNTs). The ESi-MWCNTs were then chosen as fillers to improve the mechanical and tribological properties of benzoxazine-bismaleimides (BOZ-BMI) resin. The influence of ESi-MWCNTs content on the mechanical and tribological properties of BOZ-BMI resin was researched. The results showed that suitable addition of ESi-MWCNTs can largely enhance the mechanical properties and decrease the frictional coefficient and wear rate of BOZ-BMI resin dramatically. The improvement of mechanical properties is due to the chemical reaction between BOZ-BMI and ESi-MWCNTs, which based on the analysis from fourier transform infrared (FTIR). The wear mechanism of the BOZ-BMI resin was converted from adhesive wear to abrasive wear after the addition of ESi-MWCNTs, observed from the wear surface of the materials by scanning electron microscopy (SEM). The thermogravimetric analysis (TGA) shows that the BOZ-BMI composite with 0.4 wt% ESi-MWCNTs exhibits the better thermal resistance, thus can inhibit the adhesive wear during the wear effective, which is correspond the tribological properties of composites.

The tribological properties of benzoxazine-bismaleimides composites with functionalized nano-SiO2

Co-reporter:Hong-Xia Yan;Yuan Jia;Mei-Li Li ;Ting-Ting Li

Journal of Applied Polymer Science 2013 Volume 129( Issue 6) pp:3150-3155

Publication Date(Web):

DOI:10.1002/app.39031

Abstract

To improve the tribological properties of benzoxazine (BOZ) resin, bismaleimides (BMI) resin is chosen as organic phase, hyperbranched polysilane functionalized SiO₂ nanoparticles (HBPSi-SiO₂) are chosen as inorganic modifiers to prepare HBPSi-SiO₂/BOZ-BMI composites using high shear and ultrasonic processes. The effect of content of HBPSi-SiO₂ on the mechanical properties and tribological properties of the composites are investigated. The results show that suitable addition of HBPSi-SiO₂ can largely enhance the impact strength, reduce the friction coefficient, and wear rate of BOZ-BMI resin. Scanning electron microscopy is employed to research the wearing mechanism of materials. The severe wear of the BOZ pure resin is owing to fatigue wear, and the moderate wear of BOZ-BMI resin is attributed to adhesive wear. While, the mild wear of the composites with HBPSi-SiO₂ is due to abrasive wear. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Nano-Si3N4/epoxidized silane/cyanate ester composites for electronic packaging

Co-reporter:Hongxia Yan;Mengmeng Zhang;Chao Liu;Junping Zhang

Polymer Bulletin 2013 Volume 70( Issue 11) pp:2923-2933

Publication Date(Web):2013 November

DOI:10.1007/s00289-013-0997-x

A novel kind of high performance composite of nano-Si3N4/epoxidized silane/cyanate ester (nano-Si3N4/ESi/BCE) has been developed. The mechanical, thermal and dielectric properties of the composite were investigated. The impact and flexural strength values of the nano-Si3N4/ESi/BCE system are 15.7 kJ/m2 and 114.2 MPa, respectively, which are increased by about 56 and 21 % compared with those of pure BCE resin, respectively. The glass transition temperature of the nano-Si3N4/ESi/BCE system is 278.7 °C, which is nearly 30 °C higher than that of pure BCE resin. In addition, nano-Si3N4/ESi/BCE system also exhibits lower and more stable dielectric loss than pure BCE resin over the testing frequency from 10 to 50 MHz. All these improvements of properties are closely correlated to the synergistic effects between nano-Si3N4 and ESi in the BCE matrix. The novel nano-Si3N4/ESi/BCE system with the outstanding integrated properties shows great potentialities to be applied in the field of electronic packaging.

Effects of novel polyhedral oligomeric silsesquioxane containing hydroxyl group and epoxy group on the dicyclopentadiene bisphenol dicyanate ester composites

Co-reporter:Cheng Tang, Hongxia Yan, Song Li, Lihua Bai, Qing Lv

Polymer Testing (May 2017) Volume 59() pp:316-327

Publication Date(Web):May 2017

DOI:10.1016/j.polymertesting.2017.02.014

Novel silicone-based polymer containing active methylene designed for the removal of indoor formaldehyde

Co-reporter:Song Niu, Hongxia Yan

Journal of Hazardous Materials (28 April 2015) Volume 287() pp:259-267

Publication Date(Web):28 April 2015

DOI:10.1016/j.jhazmat.2015.01.064

•A novel silicone-based polymer with active methylene was explored.•Surface tension of liquid paints could be lowered using the polymer.•The polymer was easy to migrate toward the air-coating interface.•Free HCHO could effectively be removed using the polymer.•A lights on HCHO reduction without complicated preparation procedure was shielded.Indoor air pollution is caused inevitably due to complicated home decoration, in which formaldehyde is one of the most typical pollutants. It will be a convenient, economical and effective strategy to remove indoor formaldehyde if imparting a feature of formaldehyde removal to decorative coatings. We have successfully explored a novel silicone-based polymer containing active methylene used as a formaldehyde absorbent in coatings via a straightforward transesterification process using inexpensive and easily available chemicals. The polymer has been characterized by 13C NMR, FTIR, GC and GPC. Formaldehyde removal capacity of the coating films containing different contents of the polymer has been investigated. The results indicated that coatings incorporating 4 wt% of the polymer could make the coating films exhibit significant improvement on formaldehyde removal including purificatory performance (>85%) and durability of purificatory effect (>60%), compared to those consisting of absorbents without any silicon, and improve yellowing resistance performance, while other properties, such as gloss, adhesion, pencil hardness, flexibility and impact resistance, were kept almost unaffected. The chemical absorption process of the silicone-based polymer filled in interior decorative coatings is demonstrated as a promising technology to purify indoor formaldehyde and thus can reduce the harm to individuals.Download full-size image

Enhanced tribological properties of bismaleimides filled with aligned graphene nanosheets coated with Fe3O4 nanorods

Co-reporter:Chao Liu, Hongxia Yan, Zhengyan Chen, Lingxia Yuan and Tianye Liu

Journal of Materials Chemistry A 2015 - vol. 3(Issue 19) pp:NaN10565-10565

Publication Date(Web):2015/04/02

DOI:10.1039/C5TA00797F

A multifunctional silicon-containing hyperbranched epoxy: controlled synthesis, toughening bismaleimide and fluorescent properties

Co-reporter:Song Niu, Hongxia Yan, Song Li, Cheng Tang, Zhengyan Chen, Xiaoli Zhi and Peilun Xu

Journal of Materials Chemistry A 2016 - vol. 4(Issue 28) pp:NaN6893-6893

Publication Date(Web):2016/06/27

DOI:10.1039/C6TC02546C