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Zhang W.,Fujian Normal University | Lin J.,Fujian Normal University | Wang Y.,Fujian Normal University | Lin W.,Quanzhou Sansheng Rubber and Plastic Foamed Shoes Materials Co. | Zhang H.,Fujian Normal University
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2010

The authors studied the effects of co-crosslinker trimethylolpropane trimethacrylate(TMPTMA) and triallyl-isocyanurate(TAIC) on mechanical properties of the expanded polypropylene(EPP) initiated by dicumyl peroxide. The results show that the introduction of either TAIC or TMPTMA can improve the cross linking degree of PP effectively. However, the EPP cross linked with TAIC gains an increment of 18.67% in gel fraction compared to the EPP cross linked with TMPTMA and furthermore, the former has the advantage over the latter in such mechanical properties as hardness, tensile strength, tear strength and compression set at ambient and high temperature. Source


Zhang W.,Fujian Normal University | Lin J.,Fujian Normal University | Wang Y.,Quanzhou Sansheng Rubber and Plastic Foamed Shoes Materials Co. | Lin W.,Quanzhou Sansheng Rubber and Plastic Foamed Shoes Materials Co. | Zhang H.,Fujian Normal University
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2011

The expanded polypropylene material was prepared by a one-step chemical cross-linking and compression molding method, using dicumyl peroxide (DCP) as initiator, triallyl-isocyanurate (TAIC) as assist cross-linker, and azodicarbonamide (AC) as foamer. The results indicate that excellent mechanical performance of expanded polypropylene (EPP) with density between 190 g/cm3 and 240 g/cm3 is prepared under the following condition, the content of DCP in the range of 1.2 phr~1.4 phr, plastic temperature 130°C~140°C, plastic time 10 minutes~15 minutes, molding temperature 150°C~160°C and molding time 25 minutes~30 minutes, respectively. The observation of polarization microscope shows that the foamed PP has fine and uniform foams structure when the content of DCP is 1.4 phr. Source


Zhang W.,Fujian Normal University | Zhang W.,Fujian Key Laboratory of Polymer Materials | Yang L.,Fujian Normal University | Yang L.,Fujian Key Laboratory of Polymer Materials | And 4 more authors.
Journal of Applied Polymer Science | Year: 2013

1,6-Hexanediol diacrylate (HDDA), pentaerythrithyl tetramethacrylate (PETMA), and triallyl-isocyanurate (TAIC) were used as representative monomers to modify polypropylene (PP) in the presence of dicumyl peroxide (DCP) in a mixer. Fourier transformed infrared spectroscopy (FTIR) results confirmed that all the three polyfunctional monomers have been grafted on PP backbone. The shape of torque curves suggested the occurrence of grafting and/or crosslinking structure. The rheological behaviors of HDDA modified PP showed the highest G′ and lowest tan δ at low frequency, shear-thinning shifted to lower frequency in η*-ω plot, as well as more deviation from semicircle characteristic of linear PP at high viscosity in Cole-Cole plot. And, the improvement of the mechanical properties followed the order as below: TAIC < PETMA < HDDA. Meanwhile, the foamability of the modified PP samples was also investigated. The cellular structure and morphology of the obtained foams were observed by scanning electron microscopy (SEM), and the results indicated that the foamability of the three modified PPs followed the same order, demonstrating HDDA modified PP foam possessed the highest cell density and expansion ratio, and the most well-defined closed cell structure and uniformly cellular morphology. © 2013 Wiley Periodicals, Inc. Source


Zhang W.,Fujian Normal University | Zhang W.,Fujian Key Laboratory of Polymer Materials | Yang L.,Fujian Normal University | Yang L.,Fujian Key Laboratory of Polymer Materials | And 6 more authors.
Polymer Engineering and Science | Year: 2013

In this work, zinc N,N-dimethyldithiocarbamate (ZDMC) was used to mediate the melt modification of polypropylene (PP) with 1,6-hexanediol diacrylate (HDDA) in an internal mixer in the presence of dicumyl peroxide (DCP). Fourier transformed infrared spectroscopy analysis revealed that HDDA was directly grafted onto PP backbone. The dependence of torque on processing time indicated that the presence of ZDMC restrained the degradation of PP, and the end-torque value increased with the addition of ZDMC. Dynamic rheological measurement indicated that the modified PP possessed higher G' and lower tan δ at low frequency, displaying an increase in η* and disappearance of Newtonian plateau in η*-ω plot, as well as larger radius of semicircle in Cole-Cole plot. All the rheological characterizations, together with the decreased gel content with the increase of ZDMC, confirmed the formation of long-chain branching. Subsequently, the foamability of the modified samples was investigated by one-step compression-molding process. The cellular structure and morphology of the obtained foams were observed by scanning electron microscopy, and the results showed that the addition of ZDMC decreased the cell size, increased the cell density, and brought about well-defined closed cell structure. Copyright © 2012 Society of Plastics Engineers. Source

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