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Study on Preparation and Properties of In-Situ-Compatibilized PP/POE Blends

Author: RenXingLin
Tutor: WangBiaoBing
School: University of North
Course: Materials Science
Keywords: Polypropylene The ethylene/1-butene - octene copolymer Situ compatibilization Toughening Morphology Crystallization kinetics Rheological behavior
CLC: TQ325.14
Type: Master's thesis
Year: 2008
Downloads: 139
Quote: 1
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Abstract


In order to overcome the shortcomings of polypropylene low temperature brittleness, meet the requirements for use of the automobile bumpers, the subject of a new polyolefin elastomer POE as toughening material, the use of in situ compatibilization technology in order to improve the mechanical properties of polypropylene. Dicumyl peroxide (DCP) as crosslinker, trimethylolpropane triacrylate (TMPTA) crosslinker was prepared in the mixer in order to assist the PP / POE blend. Using DSC, capillary rheometer, polarized light microscopy and scanning electron microscopy (SEM) to study the mechanical properties of PP / POE blends, phase crystallization kinetics and rheological behavior. The mechanical properties of the study results show that: in situ compatibilization technology can significantly improve the impact properties of polypropylene matrix. At room temperature and low-temperature impact strength maximum reach 52.03KJ / m ~ 2 and 37.29KJ / m ~ 2, compared with pure PP were increased by 11.74 times and 16.28 times, respectively. With the increase in the DCP content dispersed phase POE particle size becomes smaller, more uniform dispersion, the two-phase interface structure also gradually clear interface consists of two phases to a homogeneous fuzzy interface structural transformation, two-phase interfacial adhesion enhancement. Isothermal crystallization study results show that: the Avrami equation good description isothermal crystallization behavior of the PP / POE blends. The POE join can play the role of heterogeneous nucleation, increase the nucleation rate of crystallization of PP. PP and PP / POE blends crystal growth for the coexistence of two-dimensional the discotic growth and three-dimensional spherulite growth. Hoffman-Weeks Theoretical derived simple blending equilibrium melting point lower than that of pure PP situ compatibilization system balance is higher than the melting point of pure PP and simple blending and in situ compatibilizer perpendicular to the direction of the molecular chain folding free energy σ_e than pure PP. The nonisothermal crystallization research results show that: the Ozawa theory does not apply to the description of the PP / POE blends nonisothermal crystallization process, while the modified Avrami equation and Mo can handle this process well. POE join the nucleation rate of crystallization of the blends, but did not change the the PP matrix nucleation and crystal growth law, are instantaneous nucleation and three dimensional growth. The data obtained show that by the Hoffman-Lauritzen theory and its corollaries Poe added and in situ compatibilizer reduced the perpendicular to the chain direction of the folding free energy and the corresponding crystallization temperature the crystallization activation energy. The polarizing microscope results show that: the addition of POE blends the increase in the number of spherulites, particle size decreases. The research results show that the rheological behavior: PP / POE simple blending and in situ compatibilization system of non-Newtonian index is less than 1, pseudoplastic. In the same shear rate, with the increase of the DCP content, PP / POE blend of the shear stress gradually decreased, indicating that DCP added refined POE dispersed phase phase domains. Situ compatibilization system activation energy of viscous flow than the simple blend is low, indicating that the melt viscosity of the former is less sensitivity to temperature changes than the latter. However, as the shear rate increases, the activation energy of viscous flow tends to decrease, indicating that the elevated processing temperatures favor the processing performance of the system at low shear rates, appropriate.

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CLC: > Industrial Technology > Chemical Industry > Synthetic resins and plastics industry > Polymer resin and plastic > Polyolefin plastic > Polypropylene
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