Blends of polypropylene resins with a liquid crystalline polymer. I. Isothermal crystallization

Marinelli, Alessandra Lucas; Bretas, Rosário Elida Suman

doi:10.1002/app.11386

Cited by 44 publications

(25 citation statements)

References 34 publications

(44 reference statements)

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“…Thermograms were recorded with the heating rate of 10 °C/min from a range of 30° to 200 °C using differential scanning calorimeter apparatus (DSC, Netzsch DSC200). The crystallinity degree of nano-composite samples from DSC was estimated using W c = ∆H f /∆H°, where ∆H f is the heat of fusion obtained after integrating the area under the melting curve, and ∆H°=209 J/g is the reference heat of fusion for 100% crystalline polypropylene in the first run 18 .…”

Section: Characterization Of Pp/tio 2 Nano-composite Samplesmentioning

confidence: 99%

Photocatalytic degradation of polypropylene/TiO2 nano-composites

et al. 2014

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In this research, we have investigated the photocatalytic degradation of carbon-coated TiO 2 nanoparticles in polypropylene-based nano-composites. For this purpose, polypropylene-based nano-composites were prepared using carbon-coated TiO 2 nanoparticles and commercially available TiO 2 nanoparticles (Degussa, P25). Our results from SEM, FTIR, and tensile tests showed that the photocatalytic property of TiO 2 causes chain scission reactions, crosslinking and consequently photocatalytic degradation of polypropylene that affects the mechanical properties of exposed nano-composites. We have observed that with greater carbon content of the TiO 2 nano-powders, there is less photocatalytic degradation.

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Section: Characterization Of Pp/tio 2 Nano-composite Samplesmentioning

confidence: 99%

Photocatalytic degradation of polypropylene/TiO2 nano-composites

et al. 2014

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“…Also, the percentage crystallinity is calculated based on equation (7). The reference for 100 per cent crystalline polypropylene was 209 J/g [25].…”

Section: Injection Moulding Experiments Resultsmentioning

confidence: 99%

Evaluating the use of functionally graded materials inserts produced by selective laser melting on the injection moulding of plastics parts

Beal

Erasenthiran

Ahrens

et al. 2007

Proceedings of the Institution of Mechanical Engineers, Part B:

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The demand for productivity and shape complexity on the injection moulding industry necessitates new research to improve tool design, material, and manufacturing. A research field is the development of functionally graded materials (FGMs) to build injection moulds. For example, moulds built with the FGMs technique can have distinctive regions with higher heat conduction. Higher rates of heat transfers from thicker regions of the injected part can be useful to produce better and cheaper injection moulded polymer parts. It is possible to obtain moulds with differential conductivity by adding locally, during the fabrication of the mould, copper to the mould base material such as tool steel. In this work, an investigation into the effect of FGM copper (Cu)-tool steel mould insert over polymer injected parts is presented. The work is divided in two parts: a numerical thermal analysis comparison between Cu-tool steel graded and tool steel inserts and an injection moulding experiment with comparisons between mould surface temperature and degree of crystallinity of polypropylene parts. The numerical model was used to compare different behaviour of the mould heat transfer according to the mould insert material. Thereafter, a bolster was built to hold FGMs and tool steel inserts obtained by a selective laser fusion process. Polypropylene was injected over the inserts to compare with the numeric results. To observe the effect of the cooling rate in the polypropylene parts using the graded inserts, the degree of crystallinity of the parts was measured by differential scanning calorimetry (DSC) test. The temperature of the mould was also evaluated during the injection cycles. The results showed that the graded Cu-tool steel inserts tested had lower capacity to store heat energy. As Cu was added to the tool steel, the mixture proved to transfer heat more efficiently but it had less capacity to absorb heat.

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“…Reinforcing effects have been observed in PET/Vectra blends processed at conditions of high extensional flow such extrusion or spinning with high draw ratios. 3,[17][18][19][20][21][22] The application of a specific compatibilizer can improve the adhesion between the phases and consequently enhance the mechanical properties.…”

Section: A950mentioning

confidence: 99%

“…The compatibilizer agent proved efficient for both PET/LCP systems. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] have attempted to achieve composite-like materials by reinforcing a thermoplastic with a thermotropic liquid crystalline polymer (LCP). Most of the physical and mechanical properties of these composites and their processability behavior are partially or totally dependent on the degree of the molecular orientation, which results of the melt processing and relaxation effects.…”

Section: A950mentioning

confidence: 99%

Molecular orientation of extruded PET/LCP blend films. Part I: Polarized infrared spectroscopy

Branciforti

Silva

Bretas

2006

J of Applied Polymer Sci

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The polarized infrared (IR) spectroscopy technique was used to evaluate the surface uniaxial molecular orientation of films of poly(ethylene terephthalate) (PET), two thermotropic liquid crystalline polymers (LCPs), Vectra 1 A950 and Rodrun 1 LC5000, and their blends obtained by extrusion. The molecular orientation of the LCP and of the crystalline and amorphous PET phases in the draw direction was evaluated along the transverse section of the films and as a function of the blend composition. A compatibilizer agent was used to improve the interfacial adhesion between the PET and LCPs. The results showed that the surface molecular orientation of both LCPs was very high along the draw direction. However, when blended, the orientation of the LCP phase decreased drastically, it was dependent of its content and varied along the transverse section of the extruded films. The maximum orientation was observed in the blend with 5 wt % LCP content and at the position where the shear rate was maxima. The LCP Vectra 1 A950 showed higher orientation than the Rodrun 1 LC5000, as a pure material and as blended. For the PET phases, an alignment of the amorphous phase in the draw direction due to the presence of LCP and compatibilizer agent was observed. The crystalline phase of PET, however, showed no significant orientation in the draw direction. The compatibilizer agent proved efficient for both PET/LCP systems.

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Blends of polypropylene resins with a liquid crystalline polymer. I. Isothermal crystallization

Cited by 44 publications

References 34 publications

Photocatalytic degradation of polypropylene/TiO2 nano-composites

Photocatalytic degradation of polypropylene/TiO2 nano-composites

Evaluating the use of functionally graded materials inserts produced by selective laser melting on the injection moulding of plastics parts

Molecular orientation of extruded PET/LCP blend films. Part I: Polarized infrared spectroscopy

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