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Pure PP (pure + pp)

Distribution by Scientific Domains
Polymers and Materials Science83%

Selected Abstracts

Rheological, morphological, mechanical, and barrier properties of PP/EVOH blends

ADVANCES IN POLYMER TECHNOLOGY, Issue 3 2001
Jong Ho Yeo
Using the biaxially oriented film process, polypropylene (PP)/ethylene-vinyl alcohol copolymer (EVOH) blends with an improved barrier property could be obtained by generating a laminar structure of the dispersed phase in the matrix phase. This laminar morphology, induced by biaxial orientation, was found to result in a significant increase in the oxygen barrier property of PP/EVOH (85/15) blends by about 10 times relative to the pure PP. In this study, compatibility in the PP/EVOH blend system was evaluated by investigating the influence of compatibilizer on the rheological, morphological, and mechanical properties of the blends. In addition, the effects of compatibilizer content, draw ratio, and draw temperature on the oxygen permeability and morphology of biaxially drawn blend films were also studied. It was revealed that an optimum amount of compatibilizer, maleic anhydride grafted PP, should be used to improve the barrier property of the PP/EVOH blends with a well-developed laminar structure. The draw ratio and draw temperature had a significant influence on the permeability of the blends. The blend films exhibited a more pronounced laminar structure when the blends were stretched biaxially under processing conditions of higher draw ratio and draw temperature, resulting in higher barrier properties. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 191,201, 2001 [source]

Preparation and properties of dynamically cured PP/MAH- g -EVA/epoxy blends

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2009
Xueliang Jiang
Abstract A method concerning with the simultaneous reinforcing and toughening of polypropylene (PP) was reported. Dynamical cure of the epoxy resin with 2-ethylene-4-methane-imidazole (EMI-2,4) was successfully applied in the PP/maleic anhydride-grafted ethylene-vinyl acetate copolymer (MAH- g -EVA), and the obtained blends named as dynamically cured PP/MAH- g -EVA/epoxy blends. The stiffness and toughness of the blends are in a good balance, and the smaller size of epoxy particle in the PP/MAH- g -EVA/epoxy blends shows that MAH- g -EVA was also used as a compatibilizer. The structure of the dynamically cured PP/MAH- g -EVA/epoxy blends is the embedding of the epoxy particles by the MAH- g -EVA. The cured epoxy particles as organic filler increases the stiffness of the PP/MAH- g -EVA blends, and the improvement in the toughness is attributed to the embedded structure. The tensile strength and flexural modulus of the blends increase with increasing the epoxy resin content, and the impact strength reaches a maximum of 258 J/m at the epoxy resin content of 10 wt %. DSC analysis shows that the epoxy particles in the dynamically cured PP/MAH- g -EVA/epoxy blends could have contained embedded MAH- g -EVA, decreasing the nucleating effect of the epoxy resin. Thermogravimetric results show the addition of epoxy resin could improve the thermal stability of PP, the dynamically cured PP/MAH- g -EVA/epoxy stability compared with the pure PP. Wide-angle x-ray diffraction analysis shows that the dynamical cure and compatibilization do not disturb the crystalline structure of PP in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source]

Ultrasonically Initiated Grafting of Maleic Anhydride onto Poly(propylene)

MACROMOLECULAR REACTION ENGINEERING, Issue 1 2007
Xiumin Tan
Abstract This paper presents the studies on the grafting of MAH onto PP performed in solution by means of ultrasonic initiation. The effect of sonic intensity and monomer concentration on the amount of grafted MAH was investigated. It was found that grafting reaction could be initiated by ultrasound at ambient temperatures in the absence of an initiator. The quantity of product grafted was found to be 1.35%. It has been shown that optimum conditions for grafting are reached at an ultrasonic intensity of 300 W and a MAH concentration of 30%. PP- g -MAH is characterized by FTIR and XRD. DSC shows that the crystallinity of PP- g -MAH is lower than that of pure PP. [source]

Effects of stearic acid on the interface and performance of polypropylene/superfine down powder composites

POLYMER COMPOSITES, Issue 12 2009
Xin Liu
To manufacture the hygroscopic sheets available for functional application, superfine down powder (SDP) and stearic acid modified superfine down powder (MSDP) were, respectively, blended and extruded with polypropylene (PP) to produce composite pellets, and the extruded pellets were hot-pressed into composite sheets. The chemical reaction between SDP and stearic acid was characterized using the attenuated total reflection attachment on the Fourier transform infrared. PP/MSDP composites showed more uniform powder dispersion in PP matrix, higher compatibility, and better mechanical properties than that of PP/SDP composites, which showed an evident decrease in tensile strength and elongation at break compared with pure PP. It was worth noting that the Young's modulus of PP/SDP composites was higher than that of pure PP, but lower than that of PP/MSDP composites. The addition of SDP led to a large increase in water absorption of PP/SDP composites. However, the water absorption of PP/MSDP composites decreased slightly compared with that of PP/SDP composites. Furthermore, the effects of SDP and MSDP on the microstructural and thermal properties of different composites were also investigated, respectively. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers [source]

Effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/,-nucleating agent system

POLYMER COMPOSITES, Issue 12 2008
Zhiping Lv
The effect of zeolite 5A on the crystalline behavior of polypropylene (PP) in PP/,-nucleating agent system was investigated with X-ray diffractometer (XRD), differential scanning calorimeter (DSC), and polarized light microscope (PLM) in this study. Zeolite 5A has less effect on crystalline phase of PP/,-nucleating agent than does n -CaCO3, which is ascribed to the stronger surficial polarity and better dispersibility of zeolite 5A. The data of DSC indicated that the crystallization peak temperature of PP increases by 8.3°C in the presence of zeolite 5A, and n -CaCO3 increases 5.7°C in PP/TMB-5 system, relative to pure PP. And the initial crystallization temperature (Tc0) and the relative crystallinity (Xc) of PP is much more dramatically raised in the presence of zeolite 5A than CaCO3. The efficiency of zeolite 5A in reducing the spherulites size of PP was seen clearly from the PLM photographs. The mechanical testing results showed that the flexural strength and impact strength of PP/,-nucleating agent system increased in the presence of zeolite 5A. POLYM. COMPOS., 2008. © Society of Plastics Engineers [source]

Melt strength of calcium carbonate filled polypropylene melts

POLYMER INTERNATIONAL, Issue 12 2002
Nhol Kao
Abstract This paper investigates the extensional rheology (through melt strength measurement) of calcium carbonate (CaCO3) filled polypropylene (PP) melts. Different concentrations of CaCO3 filled PP were produced by mixing two master batches of pure PP and 70,wt% CaCO3 filled PP in required proportions in a counter-rotating twin-screw extruder. It was found that the melt strength of the CaCO3,PP melts was independent of CaCO3 concentrations up to 25,vol%. Further increase in CaCO3 concentration led to a severe reduction of melt strength. © 2002 Society of Chemical Industry [source]