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Wang Z.,Qingdao University of Science and Technology | Cheng X.,Qingdao University of Science and Technology | Zhao J.,Key Laboratory of Rubber Plastics
Materials Chemistry and Physics | Year: 2011

Thermoplastic vulcanizates (TPVs) based on polyethylene-octene elastomer (POE)/ethylene-propylene diene copolymer (EPDM) blends were prepared by dynamic vulcanization, the effects of the EPDM incorporation on mechanical, dynamic mechanical and morphological properties of the TPVs were investigated systemically. Experimental results indicate that compared with pure POE, the improvement of mechanical properties of POE/EPDM blends was achieved; the tensile strength and tearing strength reached the maximum at an EPDM content of 20 wt.%. It is interesting to note that the tensile set at break was decreased almost linearly with increasing EPDM loading, decreasing from 190% (at 0 phr EPDM) to 55% (at 30 wt.% EPDM), indicating the relatively large permanent deformation of POE is improved remarkably by the incorporation with EPDM. Phase contrast microscopy studies show that the vulcanized EPDM particles were uniformly dispersed in the POE matrix. RPA results show that the elastic modulus increased with increasing frequency, moreover, it is noteworthy that the storage modulus of dynamically vulcanized POE/EPDM blends was higher than that of pure POE, however, the storage modulus decreased with increasing EPDM content, the incorporation of EPDM had almost no influence on the tan δ. © 2010 Elsevier B.V. All rights reserved.


Wang Z.,Qingdao University of Science and Technology | Zhang Y.,Qingdao University of Science and Technology | Du F.,Qingdao University of Science and Technology | Wang X.,Key Laboratory of Rubber Plastics
Materials Chemistry and Physics | Year: 2012

Thermoplastic elastomer (TPE) based on high impact polystyrene (HIPS)/ethylene-vinyl acetate copolymer (EVA)/waste ground rubber tire (WGRT) powder composites were prepared by melt-compounding, and the composites were compatibilized by styrene-butadiene-styrene block copolymer (SBS). The effects of SBS compatibilizer on mechanical properties and morphological properties of the composites were investigated systemically. Experimental results indicate that SBS had a good compatibilization effect on the HIPS/EVA/WGRT composites. Compared with HIPS/EVA/WGRT composites, the tensile strength and the elongation at break went through maximum values at a compatibilizer resin content of 12 phr, which were improved by 145% and 1280%, respectively. Morphology study shows that the interface interaction was strong in the HIPS/EVA/WGRT composites compatibilized by SBS, which contributed to the significantly improved mechanical properties. Payne effect could be found in the strain sweep of HIPS/EVA/SBS/WGRT composites, which was related to the variation of interface interaction. The increasing dosage of SBS compatibilizer in the HIPS/EVA/WGRT composites weaken the Payne effect and led to the slow decrease of storage modulus. © 2012 Elsevier B.V. All rights reserved.


Wang Z.,Qingdao University of Science and Technology | Wang X.,Key Laboratory of Rubber Plastics
Journal of Thermoplastic Composite Materials | Year: 2011

Organically modified montmorillonite (OMMT) nanoparticles were obtained by hydrothermal reaction and then styrene-butadiene-styrene tri-block copolymer (SBS)/exfoliated montmorillonite nanocomposites were prepared by melt-compounding. The morphology of the OMMT nanoparticles was observed by field-emission scanning electron microscopy. The exfoliated OMMT nanoparticles consisted of several parallel MMT layers and presented disordered and floccule morphology. Mechanical tests showed that the tensile stress, elongation at break, and tearing strength were improved with increasing OMMT content, whereas the tensile strength at break slightly decreased. The relatively strong interface interaction between SBS and OMMT resulted in the improvement of the mechanical properties of SBS/OMMT nanocomposites. © The Author(s), 2011.


Hu J.,Key Laboratory of Rubber Plastics | Sun P.,CAS Institute of Chemistry | Jiang X.,Key Laboratory of Rubber Plastics | Zhu W.,CAS Institute of Chemistry | Zhang K.,CAS Institute of Chemistry
Science China Chemistry | Year: 2016

In the present study, we synthesized well-defined tadpole-shaped polystyrene (PS) via the combination of atom transfer radical polymerization (ATRP) and UV-induced strain promoted azide-alkyne cycloaddtion (SPAAC) reaction. A di-bromo ATRP initiator (Br-ini-Br) containing cyclopropenone-masked dibenzocyclooctyne group was used to prepare the linear PS with a cyclopropenone-masked dibenzocyclooctyne in the middle of the chain and bromo groups at both ends (Br-PS-Br). Then we used the single electron transfer-nitroxide radical coupling (SET-NRC) reaction to transfer the bromo end groups to azide groups (N3-PS-N3). After UV irradiation, the dibenzocyclooctyne group was quantitatively released, and intramolecularly reacted with alternative azide end group to produce the tadpole-shaped PS based on SPAAC reaction. © 2016 Science China Press and Springer-Verlag Berlin Heidelberg


Wang Y.,Key Laboratory of Rubber Plastics | Wang Y.,Qingdao Technological University | Wang Y.,Qingdao University of Science and Technology | Jow J.,Dow Chemical Company | And 4 more authors.
Fire Safety Journal | Year: 2012

In this paper, an unsteady upward burning model for polymers under UL94 vertical test conditions was developed. With this model the simulated mass loss rate of polymethylmethacrylate agreed with experimental data to a certain extent initially, and was over-predicted later but still in the same magnitude as experimental data. It was found that the edge effect was important, and the calculated maximum local mass flux of volatiles increased dramatically at the ignition time to exceed the range of reported critical mass fluxes for ignition. Sensitivity analyses showed that the activation energy and the pre-exponential factor were two most important material parameters. Increasing the char yield shows a significant reduction in the peak mass loss rate (PMLR) but only a slight increase in the ignition time (t ig) and a slight reduction in the afterflame time (t af). Increasing the density or the heat capacity increases t ig and reduces both PMLR and t af. Increasing the thermal conductivity increases t ig and decreases t af but has very little effect on PMLR. Increasing the sample thickness reduces both PMLR and t af but affects t ig less significantly than material properties. Increasing the heat feedback increases both PMLR and t af but has very little effect on t ig. © 2012 Elsevier Ltd.

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