Effect of long chain branching on the rheological behavior, crystallization and mechanical properties of polypropylene random copolymer

Cao, Jiashun; Wen, Na; Zheng, Yang

doi:10.1007/s10118-016-1830-4

Cited by 22 publications

(28 citation statements)

References 35 publications

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“…Low silica content (0 and 5 wt%) results in a small radius of the semicircle Cole‐Cole plots. This is due to the glass transition of the “free amorphous” phase of the PEG chains that causes the existence of more linear chains . Another important finding, which is imparted from Figure (b) is that higher silica concentration exhibited relatively improved silica/matrix interfacial bonding, as indicated by the imperfect semicircular Cole‐Cole plots for the BP/Q composites.…”

Section: Resultsmentioning

confidence: 81%

Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

Fauziyah

Hilmi

Zainuri

et al. 2019

J of Applied Polymer Sci

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Polyethylene glycol (PEG)/quartz (denoted as BP/Q) composites have been investigated as candidates of phase change materials (PCMs) due to their thermomechanical properties around the glass transition temperature as well as thermal properties between 30 and 600 C. Quartz (q-SiO 2 ) powders were extracted from local sand in Tanah Laut, Pelaihari, South Kalimantan, Indonesia. The composites were prepared by dispersing q-SiO 2 powders in the PEG matrix followed by the wet mixing process. The thermal properties of the composites were characterized using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), while the thermomechanical properties were examined using a dynamic mechanical analyzer (DMA) in a three-point bending mode around the PEG glass transition temperature range (−100-50 C). The morphology and interface bonding were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). From the DSC measurement, the endothermic peak of the composites showed a shift of approximately 7-12 C toward higher temperatures than that of the pure polymer. The melting enthalpy values (ΔH m ) of the BP/Q composites covered the required PCM application range, that is, between 139 and 182 J/g. The TGA of the composites showed that thermal degradation occurs in the range of 250-450 C. We found that solid-solid PCMs (ssPCMs) were successfully fabricated with the addition of 10 and 20 wt% q-SiO 2 . From DMA characterization, the BP/Q 20 wt% composite exhibited the maximum E' and the minimum energy dissipation (E"). Its E' value was approximately 250 MPa more than that of the pure PEG. The glass transition (T g ) temperatures of PEG and BP/Q composites (5, 10, and 20 wt%) were around −24.5, −19.1, −17.1, and − 5.3 C, respectively. In addition, the E" and tan δ values decreased with q-SiO 2 filler content. Furthermore, the Cole-Cole plots of the BP/Q composites revealed a better interfacial bonding between the q-SiO 2 and the PEG matrix in the composites with higher silica content. A compact morphology was shown by the BP/Q 20 wt% composite due to high silica concentration.

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Section: Resultsmentioning

confidence: 81%

Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

Fauziyah

Hilmi

Zainuri

et al. 2019

J of Applied Polymer Sci

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“…In the literature, linear viscoelastic rheology is a very well established technique for the detection of LCB, due to the high sensitivity of the LCB structure and with its associated structure change of molecular chains [44][45][46][47][48]. The complex viscosity (η*) is very sensitive to the LCB structure and the peroxide-induced degradation of PP.…”

Section: Dynamic Rheologymentioning

confidence: 99%

Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion

et al. 2020

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Long-chain branching (LCB) is known as a suitable method to increase the melt strength behavior of linear polypropylene (PP), which is a fundamental weakness of this material. This enables the modification of various properties of PP, which can then be used—in the case of PP recyclates—as a practical “upcycling” method. In this study, the effect of five different peroxides and their effectiveness in building LCB as well as the obtained mechanical properties were studied. A single screw extruder at different temperatures (180 and 240 °C) was used, and long-chain branched polypropylene (PP-LCB) was prepared via reactive extrusion by directly mixing the peroxides. The peroxides used were dimyristyl peroxydicarbonate (PODIC C126), tert-butylperoxy isopropylcarbonate (BIC), tert-Butylperoxy 2-ethylhexyl carbonate (BEC), tert-amylperoxy 2-ethylhexylcarbonate (AEC), and dilauroyl peroxide (LP), all with a concentration of 20 mmol/kg. The influence of the temperature on the competitive prevalent reactions of degradation and branching was documented via melt mass-flow rate (MFR), rheology measurements, and gel permeation chromatography (GPC). However, via extensional rheology, strain hardening could be observed in all cases and the mechanical properties could be maintained or even improved. Particularly, PODIC C126 and LP signaled a promising possibility for LCB in this study.

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“…The most frequently used post-reaction mechanisms are irradiation 6,7 and reactive processing. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Particularly, reactive processing has aroused great interest because of its flexibility and relatively low cost as it can be implemented on an extruder, which is the most common equipment in industrial plastic processing.…”

Section: Introductionmentioning

confidence: 99%

“…The route frequently followed to obtain long-chain branched PP (PPb) from PP involves one reactive step where a polyfunctional monomer is used together with a peroxide. 1,9,11,14,16,18,[20][21][22]26 In that sense, the most frequently used peroxides are dicumyl peroxide (DCP) 14,18,21,25 and 2,5-dimethyl-2,5(tert-butyl peroxy) hexane (DBPH), 9,11,20,26 while the most chosen monomers are acrylates. 9,11,16,18,[20][21][22]26 The main drawback of the one-step procedure is that the branch density is not easily controlled.…”

Section: Introductionmentioning

confidence: 99%

“…Branching can be done directly during polymerization or by post‐reaction processing. The most frequently used post‐reaction mechanisms are irradiation and reactive processing . Particularly, reactive processing has aroused great interest because of its flexibility and relatively low cost as it can be implemented on an extruder, which is the most common equipment in industrial plastic processing.…”

Section: Introductionmentioning

confidence: 99%

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Improving melt strength of polypropylene by minimal branching and blending

Guapacha

Barbosa

Vallés

et al. 2019

J of Applied Polymer Sci

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Branched polypropylenes (PPb) with markedly improved melt strength were produced without significantly affecting the processability of the original PP. A two‐step process of functionalization with MA and crosslinking with m‐XDA was used, both by batch mixing and by extrusion. Branching degrees of ~0.06 LCB/1000 monomer units or smaller were obtained. All PPbs display clear and significant strain hardening, being the PPb obtained by extrusion the one that shows the largest melt strength. This polymer has a zero‐shear‐rate viscosity slightly smaller than that of PP while its strain‐hardening index is about 10 times higher. Moreover, the nonlinear behavior of PP at elongation begins at a time similar to its terminal relaxation time or larger, while the ratio of these times reduces significantly with branching. PP/PPb blends were prepared to extend the range of obtainable melt strength in PP. They display rheological behavior between those of the mixed polymers with slight positive deviation. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48845.

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Effect of long chain branching on the rheological behavior, crystallization and mechanical properties of polypropylene random copolymer

Cited by 22 publications

References 35 publications

Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

Influence of Different Types of Peroxides on the Long-Chain Branching of PP via Reactive Extrusion

Improving melt strength of polypropylene by minimal branching and blending

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