Junrong Yu

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Name: 于俊荣; JunRong Yu

Organization: Donghua University , China

Department: State Key Laboratory for Modification of Chemical Fibers and Polymer Materials

Title: Researcher/Professor(PhD)

TOPICS

Material Chemistry

Carbon Nanotubes

Polymer

Polyesters

Chemicals
References

Modifying the carbon fiberepoxy matrix interphase with graphite nanoplatelets

Co-reporter:Wenzhen Qin;Frederic Vautard;Lawrence T. Drzal

Polymer Composites 2016 Volume 37( Issue 5) pp:1549-1556

Publication Date(Web):

DOI:10.1002/pc.23325

In this study, a novel method consisting of coating carbon fibers (CF) with graphite nanoplatelets (GnP) is investigated for its ability to modify the mechanical properties in the interphase region. Coating the CF was achieved by immersing CF in a solution of GnP dispersed in an epoxy-based solution for a few seconds. The influence of the processing conditions on the properties of the coating (thickness, homogeneity, quality of the GnP dispersion) is reported. Interfacial adhesion and the associated failure modes were evaluated by the single fiber fragmentation test. The maximum value of interfacial shear strength (IFSS) was achieved when a relative GnP concentration of 7.9 wt% on CFs, which led to 45 and 34% improvements in IFSS in comparison with the non-coated CF and epoxy coated CF, respectively. POLYM. COMPOS., 37:1549–1556, 2016. © 2014 Society of Plastics Engineers

Poly(ε-caprolactone)-grafted polydopamine particles for biocomposites with near-infrared light triggered self-healing ability

Co-reporter:Shuqiang Xiong, Yan Wang, Jing Zhu, Junrong Yu, Zuming Hu

Polymer 2016 Volume 84() pp:328-335

Publication Date(Web):10 February 2016

DOI:10.1016/j.polymer.2016.01.005

•Poly(ε-caprolactone) were covalently grafted onto polydopamine particles by in-situ polymerization.•The modified polydopamine particles dispersed homogeneously in polymer matrix.•The mechanical properties of composites significantly improved by the incorporation of fillers.•The composites showed near-infrared light response and fast optical healing ability.Polydopamine particles (PDAPs) were used as fillers for construction of multifunctional composites with poly(ε-caprolactone) (PCL) as matrix. To improve the dispersion of PDAPs in matrix and interfacial compatibility in the composites, PCL was firstly grafted onto PDAPs by in-situ ring-opening polymerization of ε-caprolactone. The successful grafting of PCL chains on PDAPs, as evidenced by the FT-IR, elemental analysis, electron microscope and dispersion tests, has greatly improved the dispersion state and interfacial adhesion between hydrophilic PDAPs and hydrophobic PCL, thus resulted in increased degree of crystallinity, and significantly improved modulus and yield strength of PCL. The photothermal effect of PDAPs have also endowed the composites with good photothermal conversion ability. The temperature of composites could rapidly rise up to the melting temperature of polymer upon exposure to near-infrared light, and thus allowed fast optical healing and fully recovered mechanical properties of the composites upon damage based on a melting-recrystallization mechanism.

Preparation, structure and properties of boron modified high-ortho phenolic fibers

Co-reporter:Bin Chen;Yingsong Zhou;Yan Wang;Jing Zhu;Zuming Hu

Fibers and Polymers 2016 Volume 17( Issue 5) pp:678-686

Publication Date(Web):2016 May

DOI:10.1007/s12221-016-5651-4

Boron modified high-ortho phenolic fibers (o-BPFs) were prepared by melt-spinning from boron modified highortho phenolic resins (o-BPRs) with the weight-average molecular weight of 4973 g/mol, followed by being cured in a solution of formaldehyde and hydrochloric, and then heat-treated under high temperature. Gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (NMR) were used to measure the average molecular weight and ortho/para (o/p) ratio of o-BPRs. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the chemical and morphological structures of o-BPRs and o-BPFs. Thermogravimetric analysis (TGA) was employed to examine the thermal stability properties of different resins and fibers and the tensile strength of fibers was measured by a tensile tester. It was found that under proper curing and heat-treatment conditions, the tensile strength of o-BPFs reached 213.6 MPa and the char yield in N2 atmosphere at 800 °C attained 75.4 %. Compared with phenolic fibers (PFs), the decomposition temperatures at 5 % weight loss of o-BPFs in N2 and air atmospheres were increased by 156.8 °C and 219.0 °C, respectively.

Preparation of KH570-SiO2 and their modification on the MF/PVA composite membrane

Co-reporter:Yingsong Zhou;Xuexin Wang;Yan Wang;Jing Zhu

Fibers and Polymers 2015 Volume 16( Issue 8) pp:1772-1780

Publication Date(Web):2015 August

DOI:10.1007/s12221-015-5284-z

Melamine-formaldehyde/polyvinyl alcohol (MF/PVA) composite membranes modified by nano silica (SiO2) and silane coupling agent KH570 modified SiO2 (KH570-SiO2) were prepared. The surface properties and morphology of KH570-SiO2 were characterized using fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TGA), contact angle measurement instrument and X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and particle size analyzer. The morphology and properties of nanoparticles modified MF/PVA membranes were also studied with scanning electron microscopy (SEM), TGA, dynamic mechanical analysis (DMA) and tensile tester. The results show that KH570 is grafted on the surface of nano SiO2. KH570-SiO2 has better dispersion in MF/PVA resin than that of unmodified SiO2. The thermal stability, mechanical and crystallizing properties of MF/PVA membrane are increased after modified with nano SiO2. KH570-SiO2 makes MF more compatible with PVA resin, and further increases the mechanical properties and thermal stability of MF/PVA membrane.

Effect of hard segment length on the properties of poly(ether ester) elastomer prepared by one pot copolymerization of poly(ethylene glycol) and cyclic butylene terephthalate

Co-reporter:Yinhe Su;Yan Wang;Jing Zhu;Zuming Hu

Journal of Polymer Research 2015 Volume 22( Issue 10) pp:

Publication Date(Web):2015 October

DOI:10.1007/s10965-015-0840-1

A series of poly(ether ester) thermoplastic elastomer were synthesized by a novel single step of cyclic butylene terephthalate (CBT) and poly(ethylene glycol) (PEG) in the presence of stannoxane catalyst at an elevated temperature. The resultant copolymers (pCBT–PEG) based on polymerized cyclic butylene terephthalate (pCBT) as the hard segment and PEG as the soft segment were characterized by means of fourier transform infrared spectrometer (FI-IR), proton nuclear magnetic resonance (1H NMR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) testing. The influence of hard segment length on the properties of the copolymer was investigated in the case of the soft segment length remaining constant. It is found that the pCBT segment length calculated from 1H NMR spectra was decreased with the increase of PEG content. The glass transition, melting and crystallization temperatures and the degree of crystallinity of hard segments were increased with the increase of the pCBT segment length. Thermogravimetry (TG) and derivative TG (DTG) results revealed that the thermal degradation of copolymers was slower than that of the pCBT homopolymer. Mechanical properties of polymers were also reported and the stiffness of the copolymer was improved with the increase of hard segment length.

Mechanical and electrical properties of carbon fiber composites with incorporation of graphene nanoplatelets at the fiber–matrix interphase

Co-reporter:Wenzhen Qin, Frederic Vautard, Lawrence T. Drzal, Junrong Yu

Composites Part B: Engineering 2015 Volume 69() pp:335-341

Publication Date(Web):February 2015

DOI:10.1016/j.compositesb.2014.10.014

In this study, carbon fibers (CFs) were coated with graphene nanoplatelets (GnP), using a robust and continuous coating process. CFs were directly immersed in a stable GnP suspension and the coating conditions were optimized in order to obtain a high density of homogeneously and well-dispersed GnP. GnP coated CFs/epoxy composites were manufactured by a prepreg and lay-up method, and the mechanical properties and electrical conductivity of the composites were assessed. The GnP coated CFs/epoxy composites showed 52%, 7%, and 19% of increase in comparison with non-coated CFs/epoxy composites, for 90° flexural strength, 0° flexural strength and interlaminar shear strength, respectively. Meanwhile, incorporating GnP in the CF/epoxy interphase significantly improved the electrical conductivity through the thickness direction by creating a conductive path between the fibers.

Mussel-Adhesive-Inspired Fabrication of Multifunctional Silver Nanoparticle Assemblies

Co-reporter:Shuqiang Xiong, Yan Wang, Jing Zhu, Junrong Yu, and Zuming Hu

Langmuir 2015 Volume 31(Issue 19) pp:5504-5512

Publication Date(Web):April 28, 2015

DOI:10.1021/acs.langmuir.5b00820

The assembly of metal nanoparticles (NPs) has attracted a great deal of attention recently because of their collective properties that could not be exhibited by individual NPs. Here a one-step approach was reported for the fabrication of spherical silver NP assemblies (AgNAs). The formation of AgNAs simply included the stirring of silver ammonia and 3,4-dihydroxy-l-phenylalanine (DOPA) in aqueous solution at room temperature, in which DOPA acted as a reductant for AgNPs first because of its reducing ability and then directed the assembly of AgNPs into AgNAs. The AgNAs exhibited hierarchical structure with controllable sizes ranging from 180 to 610 nm by adjusting the concentrations of reagents. The two individual components, AgNPs and polyDOPA, also allowed AgNAs with multiple functions as demonstrated in this study of durable catalytic activity, high SERS sensitivity, and good antioxidant properties. The thin polyDOPA layer coated on AgNAs further offered the opportunity to modify the surface of AgNAs. The results presented here may provide a green and facile approach to designing multifunctional NP assemblies.

Preparation, morphology, and adhesive and mechanical properties of ultrahigh-molecular-weight polyethylene/SiO2 nanocomposite fibers

Co-reporter:Yi Zhang;Chengjun Zhou;Lei Chen;Zuming Hu

Polymer Composites 2010 Volume 31( Issue 4) pp:684-690

Publication Date(Web):

DOI:10.1002/pc.20847

Abstract

A simple treatment approach has been performed to achieve enhanced surface properties of ultrahigh-molecular-weight polyethylene (UHMWPE) fibers by incorporation of nano-silicon dioxide (SiO₂) in the presence of silane coupling agent during gel-spinning process. The SiO₂-treated UHMWPE (UHMWPE/SiO₂) nanocomposite fibers with different nano-SiO₂ compositions were characterized with Fourier transform infrared spectra, scanning electron microscopy, and wide-angle X-ray diffraction, and their interfacial adhesion and mechanical properties were also investigated. The nano-SiO₂ can be trapped on the surface of the fibers to form rough surface for UHMWPE/SiO₂ fibers, and diffused into the inner of fibers to induce the lower crystal sizes and higher crystallinity of polyethylene in UHMWPE/SiO₂ fibers. The resulting UHMWPE/SiO₂ fibers therefore exhibit a dramatic enhancement in the adhesive properties because of the combination of rougher surface compared with those of UHMWPE fiber and polar groups absorbed on the surface of fibers. The mechanical properties of UHMWPE/SiO₂ nanocomposite fibers are enhanced simultaneously because of the influence of nano-SiO₂ on the structure of UHMWPE crystalline regions and fibrils. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers