Xinxin Li

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Name: 李欣欣; Li, XinXin

Organization: East China University of Science and Technology , China

Department: School of Materials Science and Engineering

Title: Associate Professor(PhD)

TOPICS

Polymer

Polyimide PEEK

Chemicals
References

Graphene/MWNT/Poly(p-phenylenebenzobisoxazole) Multiphase Nanocomposite via Solution Prepolymerization with Superior Microwave Absorption Properties and Thermal Stability

Co-reporter:Jiasong HuaYanxiao Li, Xiaoyun Liu, Xinxin Li, Shaoliang Lin, Jinlou Gu, Zhong-Kai Cui, Qixin Zhuang

The Journal of Physical Chemistry C 2017 Volume 121(Issue 2) pp:

Publication Date(Web):December 27, 2016

DOI:10.1021/acs.jpcc.6b11925

This paper demonstrates both the high-performance microwave absorption properties and the superior thermal stability of graphene/multiwalled carbon nanotubes (MWNTs)/poly(p-phenylenebenzobisoxazole) (PBO) composites synthesized via in situ polymerization of functionalized PBO precursor with graphene oxide/MWNTs nanocomposites, followed by high-temperature calcination. The incorporation of three-dimensional graphene/MWNTs network significantly improved the reflection loss of PBO composites (−50.17 dB at 12.58 GHz) by over 20 times than that of pure PBO (−2.33 dB at 12.58 GHz) with a sample thickness of only 2.6 mm. The effect of graphene/MWNTs content on the microwave absorption performance was also investigated. The graphene/MWNTs/PBO composite shows great promise as a microwave absorber in high-temperature environments.

Synthesis, self-assembly and pH sensitivity of a novel fluorinated triphilic block copolymer

Co-reporter:Xin-xin Li 李欣欣;Xiao Huo;Hui-jiao Han

Chinese Journal of Polymer Science 2017 Volume 35( Issue 11) pp:1363-1372

Publication Date(Web):25 August 2017

DOI:10.1007/s10118-017-1963-0

A novel fluorinated triblock copolymer incorporating 2-ethylhexyl methacrylate (EHMA), tert-butyl methacrylate (tBMA) and 1H,1H,2H,2H-perfluorodecyl acrylate (FA) (PEHMA-b-PtBMA-b-PFA) was first synthesized using three successive reversible addition fragmentation chain transfer (RAFT) polymerization and the subsequent hydrolyzing at acidic condition. The as-fabricated triblock copolymer exhibited an interesting morphology evolution from the multi-compartment rod-like structure to spherical structure along with the addition of a selective solution. At the same time, a visible phase separation domain could be seen in the core area due to the existence of fluorocarbon segments. Furthermore, the self-assembly behavior of the triphilic copolymer at different pH was also verified by transmission electron microscopy, as well as the dynamic light scattering. These stimuli-responsive multi-compartment nanostructures may have potential applications in drug delivery.

Fabrication of ordered honeycomb amphiphobic films with extremely low fluorine content

Co-reporter:Fei Gao, Wei Wang, Xinxin Li, Lei Li, Jiaping Lin, Shaoliang Lin

Journal of Colloid and Interface Science 2016 Volume 468() pp:70-77

Publication Date(Web):15 April 2016

DOI:10.1016/j.jcis.2016.01.035

•The honeycomb films of fluorinated copolymers are fabricated by breath figure technique.•The influence of preparation conditions on the film surface features is investigated in details.•Wetting behavior including hydrophobic property and wetting state of the films is explored.•A facile approach to fabricate amphiphobic honeycomb film with extremely low fluorine content is presented.A series of poly(methyl methacrylate)-block-poly(perfluoroalkyl ethyl acrylate) (PMMA-b-PFAEA) with various fluorine content were employed to fabricate honeycomb ordered films via breath figure strategy. The influences of temperature, concentration, relative humidity, fluorine content on the morphology of porous films were investigated. Wetting behavior including hydrophobic property and wetting state of the films was studied. High surface roughness from the porous structure and low surface free energy from the increasing PFAEA fraction led to the enhancement of hydrophobicity. Additionally, fabrication of porous films by the mixture of PMMA and PMMA-b-PFAEA was investigated. Ordered porous film with excellent hydrophobicity and oleophobicity was obtained with only 7 wt% of PMMA-b-PFAEA by simultaneous processes of breath figure mechanism and phase separation. This work facilitates our further comprehension of the mechanism of breath figure and contributes to the fabrication of porous film from fluorinated copolymers. Meanwhile, it opens a new route to prepare films possessing excellent hydrophobicity and oleophobicity with extremely low fluorine content.

Improvement of the interfacial shear strength of poly(p-phenylene benzobisoxazole) fiber/epoxy resin composite via a novel surface coating agent

Co-reporter:Rongbiao Liu;Zhewen Han;Weifeng Li;Qixin Zhuang

Polymer Composites 2016 Volume 37( Issue 4) pp:1198-1205

Publication Date(Web):

DOI:10.1002/pc.23284

Poly(p-phenylene benzobisoxazole) (PBO) fiber with a smooth surface exhibits limited interfacial interaction with resin matrix. One of the effective strategies to improve the adhesion between the fiber and resin matrix is through surface modification of the fiber. In this study, we have proposed a novel surface treatment agent based on phosphoester cross-linked castor oil (PCCO) for effective surface treatment of PBO fibers. The surface treatment agent was prepared by a simple cross-linking reaction between hydroxy phosphorylated castor oil (PCO) and epoxy resin, with alcohol as the solvent at 65°C. Once the PBO fiber was treated with this agent, the interfacial adhesion between the PBO fiber and the epoxy resin could then be improved. Systematic analyses suggest that the surface treatment with (PCO + epoxy)/alcohol solution improves the interaction of the PBO fiber with the epoxy resin matrix. The PCCO coated onto the surface of PBO fiber acts as a coupling agent, improving the interfacial shear strength (IFSS) of the PBO fiber/epoxy resin composite. Results indicate a 156% increase in IFSS without compromising the mechanical properties of the fiber. POLYM. COMPOS., 37:1198–1205, 2016. © 2014 Society of Plastics Engineers

Preparation and characterization of STRG/PI composite films with optimized dielectric and mechanical properties

Co-reporter:Pengtu Zhang, Jianjie He, Zhong-Kai Cui, Xinxin Li, Xiaoyun Liu, Shuo Zhang, Qixin Zhuang, Zhewen Han

Polymer 2015 Volume 65() pp:262-269

Publication Date(Web):18 May 2015

DOI:10.1016/j.polymer.2015.04.015

•Solvothermally reduced graphene oxide/PI composite films were fabricated.•Dielectric constant of the composite containing 1 wt% STRG was measured to be 71.•Structure and morphology of the composite films was investigated.•Mechanical and thermal properties of the composites were optimized.Polymer-based high dielectric composites have attracted considerable research attention due to their unique advantages in electronic applications. Polyimide (PI) is a class of high-performance polymers with improved heat-resistance and mechanical properties owing to its aromatic and heteroatomic functionalities, yielding an ideal material for high-temperature applications. In this paper, STRG (solvothermally reduced graphene oxide) was prepared and introduced into PI matrix by solution blending, and the dielectric, mechanical and thermal properties of these STRG/PI composites were studied. The STRG/PI composite (1 wt%) witnessed a significant increase by a factor of 23 in dielectric constant (71 at 103 Hz), compared to neat PI. In addition, the tensile strength of STRG/PI composites was improved by 105%. This study demonstrated a promising strategic approach to fabricate STRG/PI composites with enhanced dielectric and mechanical properties, serving potential candidates for high-temperature and high-dielectric applications.

Synthesis and self-assembly of a novel fluorinated triphilic block copolymer

Co-reporter:Xinxin Li, Yanhua Yang, Guojun Li and Shaoliang Lin

Polymer Chemistry 2014 vol. 5(Issue 15) pp:4553-4560

Publication Date(Web):22 Apr 2014

DOI:10.1039/C4PY00308J

A novel fluorinated diblock tercopolymer was synthesized by the reversible addition fragmentation chain transfer method, incorporating methacrylic acid, methyl methacrylate, and perfluoroalkyl ethyl methylacrylate blocks as hydrophilic, lipophilic, and fluorophilic units, respectively. Depending upon the specific triphilic balance, under control solution conditions, the block copolymer self-assembled in dimethylformamide/water dispersions induced an evolution from spheres to wormlike structures, and finally to novel nail-shaped structures, as verified by transmission electron microscopy and dynamic light scattering. The control mechanism is explained in terms of the effect of each property on the forces that govern the formation of any given morphology, namely the core-chain stretching, strong incompatibility between the lipophilic blocks and the fluorophilic blocks, and interfacial tension.

The tribological properties of poly(p-phenylene benzobisoxazole) pulp reinforced friction materials

Co-reporter:Rongbiao Liu;Xiaoyun Liu;Benben Shen ;Zhewen Han

Journal of Applied Polymer Science 2013 Volume 130( Issue 6) pp:4032-4039

Publication Date(Web):

DOI:10.1002/app.39672

ABSTRACT

Automotive friction materials reinforced by home-made poly (p-phenylene benzobisoxazole) (PBO) pulp (fibrillated organic fibers) were prepared through compression molding. The friction and wear behaviors of the obtained composite materials were evaluated using a constant rotating speed type friction tester. The PBO pulp content and the testing loads showed clear influence on the tribological properties of the composites. Friction stability, wear rate, and morphology of sliding surfaces were carefully examined to investigate the effect of the pulp ingredient in the friction materials. Scanning electron microscopy was employed to study the morphology of the surface and wear particles. The significant wear reduction was achieved when the mass fraction of PBO pulp was 3%. Wear rates of the composites with 3% PBO pulp were measured over a load range from 0.3 to 1 MPa at different temperatures. The results pointed to two facts: (1) the wear rate of the friction material increased linearly with load at low temperature (below 200°C); (2) wear status varied with the testing loads at high temperature (above 250°C). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4032–4039, 2013